1014-00004 · Hawthorne Vega & Cruz LLP · Expert Reports & Materials

ashford-appendix-b-doe-analysis.docx DOCUMENT Litigation

80 / 168 ← → ✕

Contract analysis Extract to table

ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL

UNITED STATES DISTRICT COURT EASTERN DISTRICT OF TEXAS MARSHALL DIVISION

OPTIWAVE SEMICONDUCTOR CORP.,

Plaintiff,

LUMICORE TECHNOLOGIES, INC.,

Defendant.

Case No. 2:24-cv-00319-JRG

Hon. James R. Gilstrap

EXPERT REPORT OF DR. CAROLINE ASHFORD

APPENDIX B: DOCTRINE OF EQUIVALENTS ANALYSIS

Prepared for: Calderwood & Harkness LLP Counsel for Plaintiff Optiwave Semiconductor Corp.

Prepared by: Dr. Caroline Ashford Professor of Electrical Engineering & Photonics Northfield Institute of Technology Evanston, Illinois

Date: DRAFT — for finalization by June 15, 2025 filing deadline

STATUS: DRAFT — ATTORNEY WORK PRODUCT / PRIVILEGED AND CONFIDENTIAL

RELATED DOCUMENTS: Expert Report of Dr. Caroline Ashford — Infringement (main report); Appendix A: Claim Charts; P.R. 3-1 Infringement Contentions served September 16, 2024; Benchmark Semiconductor Analysis, LLC teardown reports (December 12, 2022; June 2023; February 2024); Lumicore design files produced in discovery (designated Highly Confidential — Source Code).

Right-click to update Table of Contents

I. INTRODUCTION AND SCOPE

I.A. Purpose of This Appendix

1. I, Dr. Caroline Ashford, have been retained by Calderwood & Harkness LLP, counsel for Plaintiff Optiwave Semiconductor Corp. ("OWS" or "Plaintiff"), to provide expert opinions on matters of infringement relating to certain United States patents owned by OWS and asserted against Lumicore Technologies, Inc. ("Lumicore" or "Defendant") in this action. This Appendix B constitutes a component of my Expert Report and is submitted in connection with Plaintiff's case-in-chief.

2. The purpose of this Appendix is to set forth my detailed analysis under the doctrine of equivalents ("DOE") for specific claim limitations in three asserted claims where literal infringement may be contested by Defendant. Specifically, this Appendix addresses the following claims and limitations:

(a) Claim 3 of U.S. Patent No. 10,891,193 (the "'193 Patent"), titled "High-Bandwidth Coherent Optical Transceiver Integrated on Silicon Substrate" — the "coherent detection module" limitation;

(b) Claim 7 of U.S. Patent No. 10,891,193 (the "'193 Patent") — the "coherent detection module" limitation as recited in the context of Claim 7's additional dependent limitations; and

(c) Claim 12 of U.S. Patent No. 11,402,015 (the "'015 Patent"), titled "Polarization-Diverse Grating Coupler for Silicon Photonic Transceivers" — the "two-dimensional sub-wavelength grating" limitation.

3. This Appendix supplements the literal-infringement analysis set forth in my main Expert Report and in Appendix A (Claim Charts). For each of the three claim limitations identified above, the main Expert Report and Appendix A present detailed literal-infringement contentions. This Appendix provides an alternative and additional analysis under the doctrine of equivalents in the event that the Court or jury determines that Lumicore's accused products do not literally satisfy one or more of these specific limitations.

4. For each DOE contention presented in this Appendix, I apply the function-way-result test as required under the doctrine of equivalents, demonstrating that the accused elements in Lumicore's products perform substantially the same function, in substantially the same way, to achieve substantially the same result as the corresponding claim limitations of the '193 and '015 Patents. I further address the applicability of prosecution history estoppel, the all-limitations rule, and potential ensnarement of the prior art, and I explain why none of these doctrines bars a finding of infringement under the doctrine of equivalents.

5. The specific accused products to which each DOE contention applies are as follows:

(a) The LumiLink 400G-ZR+ transceiver module (launched Q3 2022; Lumicore product number LL-400-ZRP-01) — accused of infringing Claims 3 and 7 of the '193 Patent under the doctrine of equivalents;

(b) The LumiLink 800G-DR8 transceiver module (launched Q1 2023; Lumicore product number LL-800-DR8-02) — accused of infringing Claims 3 and 7 of the '193 Patent and Claim 12 of the '015 Patent under the doctrine of equivalents; and

(c) The LumiEdge 1600G-LR transceiver module (launched Q4 2023; Lumicore product number LE-1600-LR-03) — accused of infringing Claims 3 and 7 of the '193 Patent and Claim 12 of the '015 Patent under the doctrine of equivalents.

6. Each of these products has been the subject of third-party teardown analysis by Benchmark Semiconductor Analysis, LLC, the results of which I have reviewed in detail and upon which I rely, in part, in forming my opinions. The analysis presented in this Appendix is further supported by Lumicore's own design files and RTL schematics produced in discovery, deposition testimony of Lumicore's Chief Technology Officer and other witnesses, the patent specifications and prosecution histories, and the technical literature in the field of silicon photonics.

I.B. Qualifications and Basis for Opinions

7. My qualifications to render the opinions set forth in this Appendix are summarized below. A complete curriculum vitae is attached to my main Expert Report as Exhibit 1 thereto, and my full qualifications statement appears at Section II of the main Expert Report.

8. I am a tenured Professor of Electrical Engineering & Photonics at the Northfield Institute of Technology in Evanston, Illinois, where I have held a faculty appointment since 2008. I hold a Ph.D. in Electrical Engineering from the Massachusetts Institute of Technology (2005), with a doctoral thesis on "Integrated Coherent Receivers on Silicon-on-Insulator Platforms," and an M.S. in Electrical Engineering from Stanford University (2001). My research and teaching focus on silicon photonics, optical transceiver design, and photonic integrated circuits ("PICs"). I have published over 120 peer-reviewed journal articles and conference papers in these fields, hold 14 United States patents as named inventor, and have served as an associate editor for the IEEE Journal of Selected Topics in Quantum Electronics and Optics Express. I have testified as an expert witness in seven prior patent litigation matters involving silicon photonic and optical communications technologies.

9. In formulating the opinions expressed in this Appendix, I have applied the perspective of a person of ordinary skill in the art ("POSITA"). Consistent with the definition I set forth in my main Expert Report and in my claim construction declaration filed on November 15, 2024, I define a POSITA as an individual possessing a Master of Science or Doctor of Philosophy degree in electrical engineering, photonics, applied physics, or a closely related discipline, with at least three years of professional experience in the design, fabrication, testing, or characterization of silicon-photonic integrated circuits, including experience with coherent optical transceiver architectures and/or grating coupler design. I understand that this POSITA definition is consistent with the definition proposed by OWS in the Joint Claim Construction Statement filed October 28, 2024.

10. In preparing this Appendix, I have reviewed and considered the following categories of materials, among others:

(a) Benchmark Semiconductor Analysis, LLC teardown reports:

(i) Report dated December 12, 2022, prepared by Kevin Ng, for the LumiLink 400G-ZR+ transceiver module (Bates Nos. OWS-BENCH-00001–00187); (ii) Report dated June 2023, prepared by Kevin Ng, for the LumiLink 800G-DR8 transceiver module (Bates Nos. OWS-BENCH-00188–00412); (iii) Report dated February 2024, prepared by Kevin Ng, for the LumiEdge 1600G-LR transceiver module (Bates Nos. OWS-BENCH-00413–00679);

(b) Lumicore design files and RTL schematics produced in discovery, including photonic-IC layout files and mask data, designated Highly Confidential — Source Code under the three-tier protective order entered by the Court on August 22, 2024 (Bates Nos. LMC-SC-000001–LMC-SC-048372);

(i) Dr. Sandra Michaud, Chief Technology Officer of Lumicore Technologies, Inc. (deposed November 19, 2024); (ii) Dr. Jian-Wei Huang, Chief Technology Officer of Optiwave Semiconductor Corp. (deposed November 5, 2024); (iii) Kevin Ng, Senior Analyst, Benchmark Semiconductor Analysis, LLC (deposed January 7, 2025);

(d) U.S. Patent No. 10,891,193 (the '193 Patent), including the specification, claims, prosecution history, and all cited references;

(e) U.S. Patent No. 11,402,015 (the '015 Patent), including the specification, claims, prosecution history, and all cited references;

(f) Provisional Application No. 62/499,117, filed April 7, 2017, which is the common priority document for both the '193 and '015 Patents;

(g) Prior art cited in Lumicore's P.R. 3-3 invalidity contentions, served October 14, 2024, comprising 23 prior-art references including patents, published patent applications, technical papers, and standards documents;

(h) Relevant technical literature and IEEE standards, including publications relating to coherent detection architectures, silicon-photonic integration methods, grating coupler design, and sub-wavelength photonic structures, as cited throughout this Appendix; and

(i) Lumicore product datasheets and marketing materials for the LumiLink 400G-ZR+, LumiLink 800G-DR8, and LumiEdge 1600G-LR, obtained through both public sources and document production in this litigation.

11. A complete list of all materials reviewed in connection with both my main Expert Report and this Appendix is set forth in Exhibit 2 to the main Expert Report. I reserve the right to supplement that list and the opinions herein in light of any additional materials produced or made available subsequent to the date of this Appendix.

I.C. Summary of DOE Contentions

12. The following table summarizes the three doctrine of equivalents contentions presented in this Appendix:

13. It is important to emphasize that literal infringement is also asserted for each of these claims and accused products, as set forth in my main Expert Report and Appendix A. The doctrine of equivalents analysis in this Appendix provides an alternative basis for a finding of infringement in the event that the trier of fact determines that Lumicore's accused products do not literally satisfy one or more of the specific claim limitations identified above. The DOE contentions and the literal-infringement contentions are not mutually exclusive; they are presented in the alternative consistent with established patent litigation practice.

14. The structure of this Appendix is as follows: Section II sets forth the governing legal framework for the doctrine of equivalents analysis; Sections III, IV, and V present the detailed DOE analysis for each of the three contentions; Section VI provides summary comparison tables and cross-references to annotated teardown photographs and design file excerpts; Section VII addresses anticipated counterarguments from Lumicore and its expert; and Section VIII states my conclusions.

II. LEGAL FRAMEWORK FOR DOCTRINE OF EQUIVALENTS ANALYSIS

15. In preparing this Appendix, I have been instructed by counsel on the relevant legal principles governing the doctrine of equivalents. The following summary reflects my understanding of those principles as applied to the analysis herein.

II.A. The Function-Way-Result Test

16. Under the doctrine of equivalents, a product or process that does not literally infringe a patent claim may nonetheless be found to infringe if, as to each limitation of the claim, the accused element performs substantially the same function, in substantially the same way, to achieve substantially the same result as the corresponding claim limitation. See Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605, 608 (1950); Warner-Jenkinson Co. v. Harborline Enterprises Davis Chem. Co., 520 U.S. 17, 39–40 (1997). This tripartite test — commonly known as the "function-way-result" test — is the principal analytical framework I have employed throughout this Appendix.

17. Critically, the doctrine of equivalents is applied on an element-by-element basis, not to the claim as a whole. Warner-Jenkinson, 520 U.S. at 29. For each of the three DOE contentions in this Appendix, I have identified the specific claim limitation at issue and the specific corresponding element in Lumicore's accused products, and I have performed the function-way-result analysis with respect to that individual limitation. All other limitations of the asserted claims are met literally, as set forth in Appendix A.

18. The relevant time frame for the equivalence inquiry is the time of infringement, not the time the patent was issued. See Warner-Jenkinson, 520 U.S. at 37. For purposes of this Appendix, the relevant time frames are as follows:

(a) For the LumiLink 400G-ZR+: Q3 2022 through the present, corresponding to the period from the product's commercial launch through the date of this report;

(b) For the LumiLink 800G-DR8: Q1 2023 through the present; and

19. As I explain in the detailed analyses below, the equivalence between the claimed elements and Lumicore's accused elements existed at the time each product was launched and continues through the present. The structural variations employed by Lumicore were well understood in the silicon photonics field at the time of infringement as interchangeable approaches to the same technological objectives achieved by the patented inventions.

II.B. Prosecution History Estoppel Considerations

20. I understand that the doctrine of prosecution history estoppel may limit the scope of equivalents available to a patentee where the patentee narrowed a claim during prosecution to overcome a prior-art rejection. See Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002). Where a claim has been narrowed by amendment for reasons relating to patentability, there is a presumption that the patentee has surrendered the territory between the original claim scope and the amended claim scope. Id. at 740. However, this presumption may be rebutted if the patentee demonstrates that:

(a) the equivalent was unforeseeable at the time of the amendment;

(b) the rationale underlying the amendment bears only a tangential relation to the equivalent in question; or

(c) there is some other reason suggesting that the patentee could not reasonably be expected to have described the insubstantial substitute in question.

Festo, 535 U.S. at 740–41.

21. Both the '193 Patent and the '015 Patent contain limitations that were narrowed during prosecution, and prosecution history estoppel is therefore a relevant consideration for each of the three DOE contentions in this Appendix. My analysis addresses estoppel as follows:

22. Regarding the '193 Patent: During prosecution, the "coherent detection module" limitation at issue in Claims 3 and 7 was narrowed in a response filed to overcome a rejection under 35 U.S.C. § 102 based on Takahashi et al., "Dense WDM Silicon Photonic MUX," IEEE Photonics Technology Letters (March 2014). As I explain in detail in Sections III.D and IV.D below, the Festo presumption does not bar the DOE contentions asserted here because the narrowing amendment bears only a tangential relation to the equivalent at issue. The amendment was directed to distinguishing a non-coherent (direct-detection) receiver architecture disclosed in Takahashi; the structural variation in Lumicore's products concerns only the integration methodology of the local oscillator within a coherent receiver — a wholly separate technological characteristic that was not implicated by the Takahashi reference or the amendment made to overcome it. I understand that Calderwood & Harkness conducted a detailed prosecution history estoppel analysis for the '193 Patent, memorialized in an internal memorandum dated October 10, 2024, and I have reviewed that analysis in forming my opinions.

23. Regarding the '015 Patent: Claim 12's "two-dimensional sub-wavelength grating" limitation was subject to a narrowing amendment during prosecution to overcome a rejection under 35 U.S.C. § 103 combining U.S. Patent No. 8,412,007 (Bergmann, issued April 2, 2013) with PCT/EP2015/071234 (Simonsen, published September 17, 2015). As I explain in detail in Section V.D below, the Festo tangential-relation exception applies because the amendment was directed to distinguishing prior-art grating structures that either lacked sub-wavelength features entirely (Bergmann) or lacked two-dimensional structuring (Simonsen), whereas Lumicore's accused grating structure does possess two-dimensional sub-wavelength features but differs only in the specific geometric profile and apodization of those features. I understand that Calderwood & Harkness's internal prosecution history estoppel analysis for the '015 Patent, dated October 12, 2024, reached the same conclusion.

II.C. All-Limitations Rule

24. I further understand that the doctrine of equivalents must be applied in a manner that does not vitiate any claim limitation. See Brilliant Instruments, Inc. v. GuideTech, LLC, 707 F.3d 1342, 1347 (Fed. Cir. 2013). The all-limitations rule requires that the DOE analysis preserve meaningful content for every limitation of the asserted claim; a finding of equivalence cannot effectively read a limitation out of the claim. The question is whether the accused element is sufficiently similar to the claimed element that the limitation retains structural and functional significance, or whether the equivalence is so broad as to render the limitation meaningless.

25. For each of the three DOE contentions in this Appendix, I have confirmed that the analysis does not vitiate any claim limitation. In each case, the accused equivalent element in Lumicore's products is structurally and functionally distinct from the prior art, possesses the core technological characteristics of the claimed element, and differs from the claimed element only in a specific, narrow structural variation. Meaningful scope remains for each claim limitation because structures that lack the core technological character of the claimed element — for example, non-coherent receivers (for the "coherent detection module" limitation) or gratings that lack two-dimensional sub-wavelength features (for the "two-dimensional sub-wavelength grating" limitation) — remain outside the scope of even the equivalents asserted here.

III. DOE ANALYSIS — '193 PATENT, CLAIM 3: "COHERENT DETECTION MODULE" LIMITATION

III.A. Claim Language and Context

III.A.1. Full Text of Claim 3

26. U.S. Patent No. 10,891,193, titled "High-Bandwidth Coherent Optical Transceiver Integrated on Silicon Substrate," was filed on April 7, 2017, and issued on January 12, 2021. The '193 Patent claims priority to Provisional Application No. 62/499,117, filed April 7, 2017, which is a common priority document shared with the '015 Patent also asserted in this action. The named inventors are Dr. Jian-Wei Huang and Dr. Priya Ramanathan, both of whom are affiliated with OWS.

27. Claim 3 of the '193 Patent depends from Claim 1. The full text of the relevant claims is reproduced below and is also attached as Exhibit B-1 to this Appendix:

28. Claim 1 recites:

"An optical transceiver, comprising:

a silicon substrate;

a transmitter module integrated on the silicon substrate, the transmitter module comprising a laser source optically coupled to at least one Mach-Zehnder modulator configured to modulate an optical carrier signal with electrical data signals at a data rate of at least 100 Gbps per wavelength;

a receiver module integrated on the silicon substrate, the receiver module comprising a coherent detection module configured to recover phase and amplitude information from an incoming coherent optical signal;

a wavelength-division multiplexing element integrated on the silicon substrate; and

a control circuit electrically coupled to the transmitter module and the receiver module."

29. Claim 3 recites:

"The optical transceiver of claim 1, wherein the coherent detection module comprises:

a local oscillator source integrated on the silicon substrate and configured to generate a reference optical signal;

a 90-degree optical hybrid coupler configured to mix the incoming coherent optical signal with the reference optical signal to produce at least four mixed optical output signals representing in-phase and quadrature components of the incoming coherent optical signal;

at least two pairs of balanced photodetectors, each pair configured to detect a respective in-phase or quadrature component of the mixed optical output signals; and

a transimpedance amplifier array electrically coupled to the balanced photodetectors."

30. The limitation at issue for purposes of this DOE analysis is the "coherent detection module" as a whole as recited in Claim 3 — that is, the combination of the local oscillator source, the 90-degree optical hybrid coupler, the balanced photodetectors, and the transimpedance amplifier array, all of which are recited as components of the coherent detection module and are required to be "integrated on the silicon substrate."

III.A.2. Specification Support for "Coherent Detection Module"

31. The '193 Patent specification provides extensive disclosure of the "coherent detection module" and its constituent components. As described in the specification at column 7, lines 14–58, and column 8, lines 1–35, and as illustrated in Figures 3A through 3D, the coherent detection module is an integrated optical receiver component designed to recover both phase and amplitude information from an incoming coherent optical signal. The specification explains that this is accomplished through local-oscillator mixing, in which the incoming signal is combined with a locally generated reference signal in a 90-degree optical hybrid coupler, followed by balanced photodetection of the resulting mixed signals and subsequent digital signal processing ("DSP") to recover the transmitted data.

32. Figure 3A of the '193 Patent depicts the overall coherent detection module architecture, showing the local oscillator laser source (element 310), the 90-degree optical hybrid coupler (element 320), the two pairs of balanced photodetectors (elements 330a/330b and 330c/330d), and the transimpedance amplifier array (element 340), all fabricated on a silicon-on-insulator ("SOI") substrate. Figure 3B provides a more detailed schematic of the 90-degree optical hybrid coupler, showing its internal 2×4 multimode interference ("MMI") coupler structure. Figure 3C shows an SEM cross-section of the integrated local oscillator laser source, implemented as a III-V gain region heterogeneously integrated onto the silicon waveguide layer using a wafer-bonding approach. Figure 3D provides the detected signal constellation diagram demonstrating recovery of 16-QAM modulated data.

33. The specification further explains at column 8, lines 12–35, that the monolithic integration of all coherent detection module components on the silicon substrate provides advantages in terms of reduced optical path lengths, improved phase stability between the signal and local oscillator arms, lower power consumption, and reduced manufacturing cost compared to discrete-component coherent receiver assemblies. The specification specifically states: "By integrating the local oscillator source, the optical hybrid, and the balanced photodetectors on a single silicon substrate, the coherent detection module of the present invention achieves unprecedented levels of phase stability and compactness, enabling deployment of coherent technology in pluggable transceiver form factors for the first time." ('193 Patent, col. 8, ll. 22–30.)

34. With respect to the prosecution history narrowing, the prosecution of the '193 Patent proceeded as follows. As originally filed, Claim 1 recited a "receiver module" without specifying the type of detection employed. The examiner issued a non-final Office Action on March 12, 2019, rejecting Claims 1–10 under 35 U.S.C. § 102(a)(1) as anticipated by Takahashi et al., "Dense WDM Silicon Photonic MUX," IEEE Photonics Technology Letters, Vol. 26, No. 6, pp. 610–613 (March 2014). The Takahashi reference disclosed a silicon-photonic receiver module with a wavelength-division multiplexing element, but the receiver in Takahashi employed direct detection using PIN photodiodes, not coherent detection. In the applicant's response filed September 10, 2019, Claim 1 was amended to specify that the receiver module comprises "a coherent detection module configured to recover phase and amplitude information from an incoming coherent optical signal," thereby distinguishing the claim over Takahashi's direct-detection architecture. Dependent Claim 3, which further specifies the components of the coherent detection module, was added by amendment in the same response.

35. Critically, the amendment that introduced the "coherent detection module" limitation was directed exclusively to distinguishing the fundamental detection methodology — coherent detection versus direct detection — and not to any particular integration approach for the components of the coherent detection module. The applicant's remarks filed with the September 10, 2019 amendment stated: "Takahashi's receiver employs PIN photodiodes for direct detection without any local-oscillator mixing. In contrast, amended Claim 1 now requires a 'coherent detection module configured to recover phase and amplitude information from an incoming signal optical signal,' which requires local-oscillator mixing and is fundamentally distinct from Takahashi's direct-detection approach." (Ex. B-3 at 12.) At no point during prosecution did the applicant discuss, distinguish, or disclaim any particular integration approach for the local oscillator or any other coherent detection module component.

III.A.3. Claim Construction Context

36. The parties filed a Joint Claim Construction Statement pursuant to Patent Rule 4-3 on October 28, 2024, identifying 14 disputed claim terms across the '193 and '015 Patents. The term "coherent detection module" was not among the disputed terms; accordingly, neither party has proposed a construction that departs from its plain and ordinary meaning as understood by a POSITA.

37. However, the related term "integrated on a silicon substrate," which appears in Claim 1 (from which Claim 3 depends) and qualifies the receiver module and its coherent detection module, is a disputed claim construction term. OWS proposes that "integrated on a silicon substrate" means "formed on or within a silicon-based wafer using semiconductor fabrication processes," which would encompass both monolithic integration and heterogeneous or hybrid integration techniques commonly used in silicon photonics (including, e.g., III-V semiconductor bonding, micro-transfer printing, and flip-chip bonding onto a silicon interposer). Lumicore proposes a narrower construction: "monolithically fabricated on a single silicon die without hybrid bonding or heterogeneous integration." Under Lumicore's proposed construction, a coherent detection module that includes a separately fabricated indium phosphide (InP) local oscillator attached to the silicon photonic chip via hybrid bonding would not be "integrated on a silicon substrate."

38. The Markman hearing on claim construction is scheduled for March 14, 2025, before Judge Gilstrap. The Court's claim construction order has not yet issued as of the date of this Appendix. My DOE analysis is presented in a manner that addresses both possible construction outcomes. If the Court adopts OWS's proposed construction of "integrated on a silicon substrate," my opinion is that Lumicore's products literally satisfy the "coherent detection module" limitation, as set forth in the main Expert Report and Appendix A. If the Court adopts Lumicore's proposed construction, the DOE analysis in this Section III (and Section IV for Claim 7) provides an alternative basis for infringement, as the structural difference between the claimed and accused elements would relate only to the integration methodology of the local oscillator.

III.B. The Accused Element in Lumicore's Products

III.B.1. Technical Description of Lumicore's Detection Architecture

39. Based on my review of the Benchmark Semiconductor Analysis, LLC teardown reports, Lumicore's design files and RTL schematics produced in discovery, and the deposition testimony of Dr. Sandra Michaud, I have determined the following with respect to the coherent detection architecture employed in the accused Lumicore products.

40. LumiLink 400G-ZR+ (LL-400-ZRP-01). Kevin Ng's December 12, 2022 teardown report for the LumiLink 400G-ZR+ (OWS-BENCH-00001–00187) identified the coherent receiver subsystem as comprising the following components: (a) a silicon photonic integrated circuit ("Si-PIC") fabricated on an SOI substrate, containing waveguide routing, a 90-degree optical hybrid coupler implemented as a 2×4 MMI structure, and two pairs of germanium (Ge) balanced photodetectors monolithically integrated on the silicon die; (b) a separate indium phosphide (InP) distributed-feedback ("DFB") laser die functioning as the local oscillator source, micro-transfer-printed and bonded onto the surface of the Si-PIC using a gold-tin (AuSn) eutectic bonding process; and (c) a transimpedance amplifier ("TIA") array implemented as a separate SiGe BiCMOS integrated circuit, wire-bonded to the Si-PIC. The SEM images in the Benchmark report (OWS-BENCH-00067–00083) clearly show the InP DFB laser die bonded to the silicon photonic chip surface, with optical coupling achieved through an evanescent coupling structure fabricated in the silicon waveguide layer beneath the InP die.

41. LumiLink 800G-DR8 (LL-800-DR8-02). Kevin Ng's June 2023 teardown report for the LumiLink 800G-DR8 (OWS-BENCH-00188–00412) confirmed that the 800G product employs the same fundamental coherent detection architecture as the LumiLink 400G-ZR+, with the following specific features: the Si-PIC contains eight parallel coherent receiver channels (compared to four in the 400G-ZR+ module), each channel comprising a 90-degree optical hybrid coupler and paired balanced Ge photodetectors; the local oscillator is again a separate InP DFB laser die bonded to the Si-PIC; and the TIA array is a 65nm CMOS IC, representing a process node upgrade from the SiGe BiCMOS TIA used in the 400G-ZR+. The SEM and optical micrograph data in the Benchmark report (OWS-BENCH-00245–00278) show the same hybrid-integration approach for the local oscillator.

42. LumiEdge 1600G-LR (LE-1600-LR-03). Kevin Ng's February 2024 teardown report for the LumiEdge 1600G-LR (OWS-BENCH-00413–00679) confirmed that this newest product employs a similar but evolved version of the hybrid-integrated coherent detection architecture. Specifically, the LumiEdge module features sixteen parallel coherent receiver channels on the Si-PIC, a higher-power InP tunable laser as the local oscillator (also hybrid-bonded to the Si-PIC), an advanced 2×4 MMI hybrid coupler design optimized for the 1600G data rate, and a 7nm FinFET CMOS TIA. The local oscillator integration approach — hybrid bonding of a separate InP laser die onto the silicon photonic chip — is consistent across all three products.

43. At deposition, Dr. Sandra Michaud, Lumicore's Chief Technology Officer, described the LumiLink/LumiEdge detection architecture and provided testimony relevant to this analysis. When asked about the function of the coherent detection module in the LumiLink 400G-ZR+, Dr. Michaud testified: "The coherent receiver in our LumiLink product performs coherent detection. It mixes the incoming signal with a local oscillator reference and uses balanced photodetectors to recover the in-phase and quadrature components. That's standard coherent detection." (Michaud Dep. Tr. 142:8–14.) When asked about the integration of the local oscillator, Dr. Michaud testified: "We chose to use a separately fabricated InP laser that is bonded to our silicon PIC. This is a hybrid integration approach. We considered monolithic approaches but determined that the InP DFB laser provided superior performance for our application in terms of linewidth and output power." (Michaud Dep. Tr. 148:3–11.)

44. Dr. Michaud further confirmed that the hybrid-integration approach for the local oscillator was a design choice motivated by performance optimization, not by any fundamental difference in the detection methodology: "Whether the LO is monolithic or hybrid-bonded, the detection scheme is the same. You're mixing signal with LO in a 90-degree hybrid and detecting with balanced photodetectors. The integration method doesn't change the coherent detection principle." (Michaud Dep. Tr. 151:17–23.)

III.B.2. Identification of the Non-Literal Element

45. The specific element in Lumicore's products that may not literally satisfy the "coherent detection module" limitation of Claim 3 — under Lumicore's proposed claim construction — is the local oscillator source. Claim 3 recites "a local oscillator source integrated on the silicon substrate and configured to generate a reference optical signal." The '193 Patent specification describes an embodiment in which the local oscillator laser is heterogeneously integrated onto the SOI substrate through a wafer-bonding process, with the III-V gain region formed directly on the silicon waveguide layer.

46. Lumicore's products employ a local oscillator source that is fabricated as a separate InP DFB laser die and subsequently bonded to the surface of the silicon photonic chip using a micro-transfer-printing and AuSn eutectic bonding process. If the Court adopts Lumicore's proposed construction of "integrated on a silicon substrate" — which would require monolithic fabrication on a single silicon die without hybrid bonding or heterogeneous integration — then Lumicore's local oscillator would not literally satisfy this sub-element of the "coherent detection module" limitation.

47. However, it is my opinion that even under Lumicore's proposed construction, the structural difference between the claimed and accused elements is insubstantial. The fundamental architecture of Lumicore's coherent detection module — local oscillator mixing, 90-degree optical hybrid coupling, balanced photodetection, and TIA amplification — is structurally and functionally the same as the claimed coherent detection module. The only difference is the specific integration method used to place the local oscillator laser on the silicon substrate: the patent specification primarily describes heterogeneous wafer bonding (in which the III-V material is bonded at the wafer level and then processed into laser structures on the silicon), while Lumicore uses micro-transfer printing of pre-fabricated InP laser dies (in which the InP laser is fabricated separately and then transferred and bonded to the silicon at the die level). Both approaches result in an InP-based local oscillator laser physically located on and optically coupled to the silicon photonic substrate.

III.C. Function-Way-Result Analysis

III.C.1. Substantially the Same Function

48. The claimed "coherent detection module" of Claim 3 functions to recover phase and amplitude information from an incoming coherent optical signal for high-bandwidth data reception. Specifically, the coherent detection module generates a local oscillator reference signal, mixes the incoming signal with the reference signal in a 90-degree optical hybrid to produce in-phase (I) and quadrature (Q) components, detects those components using balanced photodetectors, and amplifies the resulting electrical signals for subsequent digital signal processing. The fundamental function is the coherent reception of optical data at high bandwidths (100 Gbps or more per wavelength) with preservation of both phase and amplitude information — capabilities that are absent in direct-detection receiver architectures.

49. Lumicore's accused detection architecture in the LumiLink 400G-ZR+, LumiLink 800G-DR8, and LumiEdge 1600G-LR performs substantially the same function. Each product's coherent detection module generates a local oscillator reference signal (using the InP DFB laser), mixes the incoming signal with the reference signal in a 90-degree optical hybrid coupler, detects the I and Q components using balanced Ge photodetectors, and amplifies the resulting electrical signals through a TIA array. The function is identical: Coherent reception of optical data with phase and amplitude recovery.

50. This functional identity is confirmed by multiple sources of evidence:

(a) Lumicore product datasheets. The datasheets for all three accused products describe their receiver subsystems as performing "coherent detection" with "phase and amplitude recovery" for "100G/200G/400G" (LumiLink 400G-ZR+), "800G" (LumiLink 800G-DR8), and "1600G" (LumiEdge 1600G-LR) data rates, respectively. The datasheets specifically reference "intradyne coherent reception" and "digital coherent processing."

(b) Dr. Michaud's deposition testimony. As quoted in paragraph 43 above, Dr. Michaud confirmed that the coherent receiver "performs coherent detection" by "mix[ing] the incoming signal with a local oscillator reference and us[ing] balanced photodetectors to recover the in-phase and quadrature components." (Michaud Dep. Tr. 142:8–14.)

(c) Benchmark teardown data. The Benchmark teardown reports for each product characterized the receiver subsystem as a "coherent intradyne receiver" performing "phase-diverse balanced detection." (OWS-BENCH-00089; OWS-BENCH-00256; OWS-BENCH-00498.)

51. A POSITA would readily understand that the function of Lumicore's coherent detection module is substantially the same as the function of the claimed coherent detection module in Claim 3 of the '193 Patent. There is no meaningful functional difference.

III.C.2. Substantially the Same Way

52. The claimed coherent detection module achieves its function through the following mechanism: a local oscillator source integrated on the silicon substrate generates a reference optical signal; a 90-degree optical hybrid coupler mixes the incoming coherent optical signal with the reference signal to produce at least four mixed optical output signals representing the I and Q components; balanced photodetectors detect the mixed signals; and a TIA array amplifies the resulting photocurrents. The critical aspect of the "way" in which the claimed element operates is the combination of intradyne local-oscillator mixing with balanced photodetection on a silicon photonic platform.

53. Lumicore's accused products achieve the same function through the same core mechanism. The InP DFB local oscillator generates a reference optical signal that is coupled into the silicon waveguide layer through an evanescent coupling structure. The reference signal is then combined with the incoming signal in a 90-degree optical hybrid coupler (implemented as a 2×4 MMI structure, the same structure described in the '193 Patent specification). Balanced Ge photodetectors — monolithically integrated on the Si-PIC in all three products — detect the mixed I and Q optical signals. A TIA array amplifies the resulting photocurrents. The signal processing chain — local oscillator mixing, balanced detection, and transimpedance amplification — is functionally and mechanistically identical.

54. The sole difference in the "way" relates to the integration approach for the local oscillator source: the '193 Patent specification describes heterogeneous wafer-level bonding of III-V material onto the SOI substrate, followed by lithographic patterning and processing of the laser structures; Lumicore uses micro-transfer printing of pre-fabricated InP DFB laser dies, followed by die-level bonding to the Si-PIC surface. Both approaches result in an InP-based laser physically situated on and optically coupled to the silicon photonic substrate. Both achieve optical coupling between the local oscillator output and the silicon waveguide through evanescent coupling structures. Both utilize the same wavelength stabilization and power control techniques. The difference is analogous to the difference between building a laser structure in situ on the silicon chip versus building it separately and then placing it on the silicon chip — the end result, in terms of the "way" the coherent detection is performed, is the same.

55. A POSITA at the time of infringement (Q3 2022 through the present) would understand these as interchangeable approaches to coherent detection on silicon photonic platforms. The literature is replete with publications recognizing that hybrid integration (die bonding) and heterogeneous integration (wafer bonding) are alternative and functionally equivalent methods for placing III-V laser sources on silicon photonic substrates. See, e.g., T. Komljenovic et al., "Heterogeneous Silicon Photonic Integrated Circuits," J. Lightwave Technol., Vol. 34, No. 1, pp. 20–35 (Jan. 2016); G. Roelkens et al., "III-V-on-Silicon Integration for Coherent Transceivers," IEEE J. Sel. Topics Quantum Electron., Vol. 24, No. 1, Art. 6100112 (Jan./Feb. 2018). Both approaches are recognized in the industry as delivering comparable coherent detection performance when implemented on silicon photonic platforms.

56. Supporting evidence from the Benchmark teardown data confirms the mechanistic equivalence. Kevin Ng's teardown reports for all three accused products include optical signal path analyses (OWS-BENCH-00091–00098; OWS-BENCH-00259–00267; OWS-BENCH-00502–00511) demonstrating that the signal flow through Lumicore's coherent detection module — from local oscillator output through the 90-degree hybrid to the balanced photodetectors — follows the same path topology as described in the '193 Patent specification.

57. In his January 7, 2025 deposition, Kevin Ng confirmed: "The optical signal path in the Lumicore receiver is essentially the same as what you'd see in a standard intradyne coherent receiver architecture. The LO light enters a 90-degree hybrid, mixes with the signal, and balanced photodetectors measure the output. The only unique aspect is how the LO laser is attached to the PIC." (Ng Dep. Tr. 87:5–12.)

58. Accordingly, it is my opinion that Lumicore's accused coherent detection module achieves its function in substantially the same way as the claimed coherent detection module of Claim 3.

III.C.3. Substantially the Same Result

59. The claimed coherent detection module yields high-bandwidth coherent signal recovery with specified performance characteristics, including bit-error rate ("BER"), signal-to-noise ratio ("SNR"), and bandwidth sufficient for 100 Gbps or greater per-wavelength data reception with advanced modulation formats (e.g., DP-QPSK, DP-16QAM). The '193 Patent specification describes performance metrics achievable with the claimed coherent detection module architecture, including BER below 10⁻¹⁵ after forward error correction ("FEC") and an electrical signal bandwidth of at least 35 GHz per photodetector pair. (See '193 Patent, col. 9, ll. 4–22.)

60. Lumicore's coherent detection module in each accused product yields substantially the same result:

(a) LumiLink 400G-ZR+: The Benchmark teardown report measured receiver sensitivity of −24 dBm at a pre-FEC BER of 4.2 × 10⁻³ for 400G DP-16QAM, with post-FEC BER below 10⁻¹⁵. The electrical bandwidth per photodetector pair was measured at approximately 38 GHz. (OWS-BENCH-00102–00107.) The Lumicore product datasheet specifies receiver sensitivity of −23 dBm and post-FEC BER below 10⁻¹⁵, consistent with the measured performance.

(b) LumiLink 800G-DR8: The Benchmark teardown report measured receiver sensitivity of −20 dBm at pre-FEC BER of 2.4 × 10⁻² for 800G operation (eight parallel 100G channels), with post-FEC BER below 10⁻¹⁵. The per-channel electrical bandwidth was approximately 36 GHz. (OWS-BENCH-00270–00278.)

(c) LumiEdge 1600G-LR: The Benchmark teardown report measured receiver sensitivity of −18 dBm at pre-FEC BER of 1.8 × 10⁻² for 1600G operation, with post-FEC BER below 10⁻¹⁵. The per-channel electrical bandwidth was approximately 42 GHz, reflecting the advanced 7nm CMOS TIA design. (OWS-BENCH-00515–00527.)

61. These performance metrics fall within the same operational envelope described in the '193 Patent specification for the claimed coherent detection module. The BER, SNR, and bandwidth performance of Lumicore's detection modules is comparable to — and in some respects superior to — the performance of the embodiments described in the patent specification. This is consistent with the expectation that incremental improvements in semiconductor process technology over time would improve performance while maintaining the same fundamental detection architecture.

62. The Lumicore specification sheets for all three products further confirm that the coherent detection results are substantially the same as those achieved by the claimed invention. The specifications describe "Coherent reception with phase and amplitude recovery," "support for DP-QPSK and DP-16QAM modulation formats," and "pluggable form factor deployment" — each of which corresponds to the results described in the '193 Patent specification as achievable with the claimed coherent detection module.

63. Accordingly, it is my opinion that Lumicore's accused coherent detection module achieves substantially the same result as the claimed coherent detection module of Claim 3.

III.D. Prosecution History Estoppel — Inapplicability

III.D.1. Nature of the Prosecution Amendment

64. As described in paragraph 34 above, during prosecution of the '193 Patent, the "coherent detection module" limitation was added to Claim 1 (and dependent Claim 3 was simultaneously added) in a response filed September 10, 2019, to overcome a § 102 rejection based on Takahashi et al. The Takahashi reference disclosed a silicon-photonic receiver module employing direct detection with PIN photodiodes for wavelength-demultiplexed intensity-modulated optical signals. Takahashi's receiver did not employ any local oscillator, did not include a 90-degree optical hybrid coupler, and did not perform coherent detection in any form.

65. The applicant's amendment distinguished the claim from Takahashi by requiring a "coherent detection module configured to recover phase and amplitude information from an incoming coherent optical signal." The applicant's arguments in the September 10, 2019 response were entirely directed to the fundamental distinction between coherent detection and direct detection:

"Takahashi discloses a receiver module with PIN photodiodes for direct detection of intensity-modulated signals. Takahashi does not disclose, teach, or suggest a coherent detection module that recovers phase and amplitude information from a coherent optical signal. Direct detection, as practiced in Takahashi, inherently discards the phase information of the optical signal. In contrast, the amended claims require coherent detection, which preserves and recovers both phase and amplitude information. Accordingly, Takahashi fails to anticipate the amended claims."

(Exhibit B-3, Applicant's Response dated September 10, 2019, at pp. 11–13.)

66. The amendment was not directed to, did not discuss, and did not distinguish any particular integration approach for the local oscillator source or any other component of the coherent detection module. The prosecution history contains no discussion of monolithic versus hybrid integration methods, no discussion of wafer-level versus die-level bonding, and no discussion of the physical arrangement of the local oscillator relative to the silicon substrate. The entirety of the prosecution distinction was between coherent and non-coherent detection.

III.D.2. Tangential Relation Exception Under *Festo*

67. Under Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002), when a claim is narrowed by amendment for reasons related to patentability, there is a presumption that the patentee surrendered the territory between the original claim and the amended claim. However, this presumption may be rebutted where "the rationale underlying the amendment [bears] no more than a tangential relation to the equivalent in question." Id. at 740; see also Insituform Techs., Inc. v. CAT Contracting, Inc., 385 F.3d 1360, 1370 (Fed. Cir. 2004).

68. The equivalent at issue in this analysis is the integration method of the local oscillator source within a coherent detection module. Specifically, the question is whether a coherent detection module with a hybrid-bonded InP local oscillator (Lumicore's approach) is equivalent to a coherent detection module with a monolithically integrated or heterogeneously bonded local oscillator (as described in the patent specification).

69. The rationale for the prosecution amendment — distinguishing coherent detection from direct detection — bears only a tangential relation to the equivalent in question. The amendment was made to overcome a reference (Takahashi) that disclosed a fundamentally different detection paradigm — direct detection — that does not employ any local oscillator at all, regardless of how such a local oscillator might be integrated. The amendment said nothing about the integration method of the local oscillator because Takahashi's receiver did not have a local oscillator. The narrowing was in the dimension of detection methodology (coherent vs. direct), not in the dimension of integration methodology (monolithic vs. hybrid).

70. A POSITA would not have foreseen that the amendment to require "coherent detection" would surrender coverage of hybrid-integrated coherent receivers. At the time of the amendment (September 2019), hybrid integration of III-V lasers onto silicon photonic chips was a well-known and widely practiced technique for building coherent receivers. A POSITA would have understood the amendment as directed to requiring any form of coherent detection — as opposed to direct detection — without regard to the specific integration approach used for the local oscillator. The concept of hybrid-bonded InP local oscillators on silicon photonic platforms was commercially available and extensively published in the literature by September 2019. See, e.g., Harborview Industries's commercial silicon photonic coherent transceivers, which employed hybrid-bonded InP lasers as of 2018; Ashbury & Co.'s (now Cisco's) hybrid silicon laser platform; and numerous academic publications on die-bonded III-V-on-silicon integration.

71. Accordingly, the Festo tangential-relation exception is satisfied, and prosecution history estoppel does not bar the DOE contention for the "coherent detection module" limitation of Claim 3.

III.D.3. No Vitiation of the Limitation

72. The DOE contention presented here does not vitiate the "coherent detection module" limitation of Claim 3. The claim limitation requires a coherent detection module with specific structural features: a local oscillator source, a 90-degree optical hybrid coupler, balanced photodetectors, and a TIA array, all integrated on a silicon substrate. Lumicore's accused element is still a coherent detection module with all of these structural features — it merely implements the local oscillator integration in a structurally non-identical manner (die-level hybrid bonding rather than wafer-level heterogeneous integration).

73. Meaningful scope remains for the "coherent detection module" limitation even when the doctrine of equivalents is applied as I have described. Non-coherent receivers (such as Takahashi's direct-detection receiver) fall outside the scope of both the literal claim and the equivalents asserted here. Receiver architectures that lack a local oscillator, that do not employ balanced photodetection, or that do not use a 90-degree optical hybrid also remain outside the scope. Entirely different detection paradigms — such as self-coherent detection, Kramers-Kronig receivers, or Stokes-vector receivers — would likewise not be captured by the equivalents analysis. The limitation thus retains meaningful content; it is not vitiated by the narrow structural equivalence at issue.

IV. DOE ANALYSIS — '193 PATENT, CLAIM 7: "COHERENT DETECTION MODULE" LIMITATION

IV.A. Claim Language and Context

IV.A.1. Full Text of Claim 7

74. Claim 7 of U.S. Patent No. 10,891,193 depends from Claim 3, which in turn depends from Claim 1. The full text of Claim 7 is reproduced below and is also attached as Exhibit B-1:

75. Claim 7 recites:

"The optical transceiver of claim 3, wherein the coherent detection module further comprises:

a polarization beam splitter integrated on the silicon substrate and configured to separate incoming light into transverse-electric (TE) and transverse-magnetic (TM) polarization components;

a polarization rotator configured to rotate the TM polarization component to a TE polarization; and

dual 90-degree optical hybrid couplers, each configured to independently process a respective polarization component using the local oscillator source,

whereby the coherent detection module is configured for polarization-diverse coherent reception of a dual-polarization optical signal."

76. Because Claim 7 depends from Claim 3 (which depends from Claim 1), Claim 7 includes all limitations of Claims 1 and 3 in addition to the limitations it recites independently. The "coherent detection module" element at issue in this Section IV is the same core element as in the Claim 3 analysis (Section III), but with the additional structural and functional requirements imposed by Claim 7's dependent limitations — specifically, the polarization beam splitter, the polarization rotator, and the dual 90-degree optical hybrid couplers configured for polarization-diverse coherent reception.

IV.A.2. Differences Between Claim 7 and Claim 3

77. Claim 7 adds three specific limitations to the coherent detection module beyond those recited in Claim 3:

(a) A polarization beam splitter integrated on the silicon substrate that separates incoming light into TE and TM polarization components;

(b) A polarization rotator that converts the TM component to TE polarization, enabling both polarization components to be processed in the TE mode by the silicon waveguide structures (which are optimized for TE-mode propagation); and

(c) Dual 90-degree optical hybrid couplers, each independently processing one of the two polarization components using the same local oscillator source, enabling full polarization-diverse coherent reception.

78. These additional limitations define a polarization-diversity receiver architecture, which is the standard architecture for receiving dual-polarization modulation formats such as DP-QPSK and DP-16QAM. The significance of these additional limitations for the DOE analysis is that they impose further structural and functional specificity on the coherent detection module, and the DOE analysis must address whether the accused products satisfy these additional requirements (literally or under DOE) in addition to the core "coherent detection module" limitation analyzed in Section III.

79. For purposes of this Appendix, I note that the additional limitations recited in Claim 7 — the polarization beam splitter, polarization rotator, and dual optical hybrid couplers — are met literally by all three accused Lumicore products, as set forth in the main Expert Report and Appendix A (Claim Charts). The DOE analysis in this Section IV is directed to the same non-literal element identified in Section III — the integration method of the local oscillator source — as that element is the only element of Claim 7 for which DOE is required.

IV.B. The Accused Element in Lumicore's Products

80. The accused products for Claim 7 are the same as for Claim 3: the LumiLink 400G-ZR+, LumiLink 800G-DR8, and LumiEdge 1600G-LR. The description of Lumicore's coherent detection architecture set forth in Section III.B above applies in full to the Claim 7 analysis and is incorporated here by reference.

81. With respect to the additional limitations unique to Claim 7, the Benchmark teardown data confirms that each accused product includes the following components:

(a) Polarization beam splitter: The Benchmark teardown reports identified an on-chip polarization beam splitter in each product's Si-PIC, fabricated as a directional coupler-based PBS in the silicon waveguide layer. (OWS-BENCH-00085 (400G-ZR+); OWS-BENCH-00249 (800G-DR8); OWS-BENCH-00492 (1600G-LR).)

(b) Polarization rotator: Each product includes a silicon waveguide polarization rotator (a mode-evolution-based TM-to-TE converter) positioned after the PBS and before the optical hybrid for the TM channel. (OWS-BENCH-00086 (400G-ZR+); OWS-BENCH-00250 (800G-DR8); OWS-BENCH-00493 (1600G-LR).)

(c) Dual 90-degree optical hybrid couplers: Each product includes two 90-degree optical hybrid couplers (2×4 MMI structures), one processing the TE polarization component and one processing the rotated TM→TE component, both utilizing the same local oscillator source split by an on-chip power splitter. (OWS-BENCH-00087–00088 (400G-ZR+); OWS-BENCH-00251–00252 (800G-DR8); OWS-BENCH-00494–00495 (1600G-LR).)

82. These components literally satisfy the corresponding limitations of Claim 7. The only non-literal element remains the local oscillator integration method, as described in Section III.B.2.

IV.C. Function-Way-Result Analysis

IV.C.1. Substantially the Same Function

83. The core function of the coherent detection module as recited in Claim 7 is the same as in Claim 3 — recovery of phase and amplitude information from an incoming signal optical signal — with the additional function of performing this recovery in a polarization-diverse manner. Specifically, Claim 7's coherent detection module functions to: (i) separate the incoming dual-polarization signal into its TE and TM components; (ii) rotate the TM component to TE; (iii) independently process both polarization components through separate coherent detection channels using a shared local oscillator; and (iv) thereby enable polarization-diverse coherent reception of a DP-QPSK or DP-16QAM optical signal.

84. Lumicore's accused coherent detection module performs substantially the same function. Each accused product's detection module separates the incoming signal into TE and TM polarization components, rotates TM to TE, independently processes both components through dual optical hybrid couplers with a shared local oscillator, and achieves polarization-diverse coherent reception. The additional function specified by Claim 7 — polarization-diverse coherent reception — is identical in Lumicore's products.

85. Evidence supporting this conclusion includes: the Lumicore product datasheets for all three accused products, which specify "dual-polarization coherent reception" and support for "DP-QPSK" and "DP-16QAM" modulation formats; Dr. Michaud's deposition testimony, in which she confirmed that the LumiLink and LumiEdge receivers "receive and process both polarization components simultaneously using polarization-diversity architecture" (Michaud Dep. Tr. 156:4–9); and the Benchmark teardown reports, which identified and characterized all polarization-diversity components in each product.

IV.C.2. Substantially the Same Way

86. The "way" in which Claim 7's coherent detection module achieves polarization-diverse coherent reception is through the specific combination of an on-chip polarization beam splitter, polarization rotator, and dual optical hybrid couplers sharing a common local oscillator on a silicon photonic substrate. Lumicore's products employ the same mechanism: the same types of on-chip polarization management components (PBS and rotator) and dual optical hybrid couplers sharing a common local oscillator, all on a silicon photonic substrate.

ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL
UNITED STATES DISTRICT COURT EASTERN DISTRICT OF TEXAS MARSHALL DIVISION
OPTIWAVE SEMICONDUCTOR CORP.,
Plaintiff,
v.
LUMICORE TECHNOLOGIES, INC.,
Defendant.
Case No. 2:24-cv-00319-JRG
Hon. James R. Gilstrap
EXPERT REPORT OF DR. CAROLINE ASHFORD
APPENDIX B: DOCTRINE OF EQUIVALENTS ANALYSIS
Prepared for: Calderwood & Harkness LLP Counsel for Plaintiff Optiwave Semiconductor Corp.
Prepared by: Dr. Caroline Ashford Professor of Electrical Engineering & Photonics Northfield Institute of Technology Evanston, Illinois
Date: DRAFT — for finalization by June 15, 2025 filing deadline
STATUS: DRAFT — ATTORNEY WORK PRODUCT / PRIVILEGED AND CONFIDENTIAL
RELATED DOCUMENTS: Expert Report of Dr. Caroline Ashford — Infringement (main report); Appendix A: Claim Charts; P.R. 3-1 Infringement Contentions served September 16, 2024; Benchmark Semiconductor Analysis, LLC teardown reports (December 12, 2022; June 2023; February 2024); Lumicore design files produced in discovery (designated Highly Confidential — Source Code).
Right-click to update Table of Contents
I. INTRODUCTION AND SCOPE
I.A. Purpose of This Appendix
1.  I, Dr. Caroline Ashford, have been retained by Calderwood & Harkness LLP, counsel for Plaintiff Optiwave Semiconductor Corp. ("OWS" or "Plaintiff"), to provide expert opinions on matters of infringement relating to certain United States patents owned by OWS and asserted against Lumicore Technologies, Inc. ("Lumicore" or "Defendant") in this action. This Appendix B constitutes a component of my Expert Report and is submitted in connection with Plaintiff's case-in-chief.
2.  The purpose of this Appendix is to set forth my detailed analysis under the doctrine of equivalents ("DOE") for specific claim limitations in three asserted claims where literal infringement may be contested by Defendant. Specifically, this Appendix addresses the following claims and limitations:
(a) Claim 3 of U.S. Patent No. 10,891,193 (the "'193 Patent"), titled "High-Bandwidth Coherent Optical Transceiver Integrated on Silicon Substrate" — the "coherent detection module" limitation;
(b) Claim 7 of U.S. Patent No. 10,891,193 (the "'193 Patent") — the "coherent detection module" limitation as recited in the context of Claim 7's additional dependent limitations; and
(c) Claim 12 of U.S. Patent No. 11,402,015 (the "'015 Patent"), titled "Polarization-Diverse Grating Coupler for Silicon Photonic Transceivers" — the "two-dimensional sub-wavelength grating" limitation.
3.  This Appendix supplements the literal-infringement analysis set forth in my main Expert Report and in Appendix A (Claim Charts). For each of the three claim limitations identified above, the main Expert Report and Appendix A present detailed literal-infringement contentions. This Appendix provides an alternative and additional analysis under the doctrine of equivalents in the event that the Court or jury determines that Lumicore's accused products do not literally satisfy one or more of these specific limitations.
4.  For each DOE contention presented in this Appendix, I apply the function-way-result test as required under the doctrine of equivalents, demonstrating that the accused elements in Lumicore's products perform substantially the same function, in substantially the same way, to achieve substantially the same result as the corresponding claim limitations of the '193 and '015 Patents. I further address the applicability of prosecution history estoppel, the all-limitations rule, and potential ensnarement of the prior art, and I explain why none of these doctrines bars a finding of infringement under the doctrine of equivalents.
5.  The specific accused products to which each DOE contention applies are as follows:
(a) The LumiLink 400G-ZR+ transceiver module (launched Q3 2022; Lumicore product number LL-400-ZRP-01) — accused of infringing Claims 3 and 7 of the '193 Patent under the doctrine of equivalents;
(b) The LumiLink 800G-DR8 transceiver module (launched Q1 2023; Lumicore product number LL-800-DR8-02) — accused of infringing Claims 3 and 7 of the '193 Patent and Claim 12 of the '015 Patent under the doctrine of equivalents; and
(c) The LumiEdge 1600G-LR transceiver module (launched Q4 2023; Lumicore product number LE-1600-LR-03) — accused of infringing Claims 3 and 7 of the '193 Patent and Claim 12 of the '015 Patent under the doctrine of equivalents.
6.  Each of these products has been the subject of third-party teardown analysis by Benchmark Semiconductor Analysis, LLC, the results of which I have reviewed in detail and upon which I rely, in part, in forming my opinions. The analysis presented in this Appendix is further supported by Lumicore's own design files and RTL schematics produced in discovery, deposition testimony of Lumicore's Chief Technology Officer and other witnesses, the patent specifications and prosecution histories, and the technical literature in the field of silicon photonics.
I.B. Qualifications and Basis for Opinions
7.  My qualifications to render the opinions set forth in this Appendix are summarized below. A complete curriculum vitae is attached to my main Expert Report as Exhibit 1 thereto, and my full qualifications statement appears at Section II of the main Expert Report.
8.  I am a tenured Professor of Electrical Engineering & Photonics at the Northfield Institute of Technology in Evanston, Illinois, where I have held a faculty appointment since 2008. I hold a Ph.D. in Electrical Engineering from the Massachusetts Institute of Technology (2005), with a doctoral thesis on "Integrated Coherent Receivers on Silicon-on-Insulator Platforms," and an M.S. in Electrical Engineering from Stanford University (2001). My research and teaching focus on silicon photonics, optical transceiver design, and photonic integrated circuits ("PICs"). I have published over 120 peer-reviewed journal articles and conference papers in these fields, hold 14 United States patents as named inventor, and have served as an associate editor for the IEEE Journal of Selected Topics in Quantum Electronics and Optics Express. I have testified as an expert witness in seven prior patent litigation matters involving silicon photonic and optical communications technologies.
9.  In formulating the opinions expressed in this Appendix, I have applied the perspective of a person of ordinary skill in the art ("POSITA"). Consistent with the definition I set forth in my main Expert Report and in my claim construction declaration filed on November 15, 2024, I define a POSITA as an individual possessing a Master of Science or Doctor of Philosophy degree in electrical engineering, photonics, applied physics, or a closely related discipline, with at least three years of professional experience in the design, fabrication, testing, or characterization of silicon-photonic integrated circuits, including experience with coherent optical transceiver architectures and/or grating coupler design. I understand that this POSITA definition is consistent with the definition proposed by OWS in the Joint Claim Construction Statement filed October 28, 2024.
10.  In preparing this Appendix, I have reviewed and considered the following categories of materials, among others:
(a) Benchmark Semiconductor Analysis, LLC teardown reports:
(i) Report dated December 12, 2022, prepared by Kevin Ng, for the LumiLink 400G-ZR+ transceiver module (Bates Nos. OWS-BENCH-00001–00187); (ii) Report dated June 2023, prepared by Kevin Ng, for the LumiLink 800G-DR8 transceiver module (Bates Nos. OWS-BENCH-00188–00412); (iii) Report dated February 2024, prepared by Kevin Ng, for the LumiEdge 1600G-LR transceiver module (Bates Nos. OWS-BENCH-00413–00679);
(b) Lumicore design files and RTL schematics produced in discovery, including photonic-IC layout files and mask data, designated Highly Confidential — Source Code under the three-tier protective order entered by the Court on August 22, 2024 (Bates Nos. LMC-SC-000001–LMC-SC-048372);
(c) Deposition transcripts:
(i) Dr. Sandra Michaud, Chief Technology Officer of Lumicore Technologies, Inc. (deposed November 19, 2024); (ii) Dr. Jian-Wei Huang, Chief Technology Officer of Optiwave Semiconductor Corp. (deposed November 5, 2024); (iii) Kevin Ng, Senior Analyst, Benchmark Semiconductor Analysis, LLC (deposed January 7, 2025);
(d) U.S. Patent No. 10,891,193 (the '193 Patent), including the specification, claims, prosecution history, and all cited references;
(e) U.S. Patent No. 11,402,015 (the '015 Patent), including the specification, claims, prosecution history, and all cited references;
(f) Provisional Application No. 62/499,117, filed April 7, 2017, which is the common priority document for both the '193 and '015 Patents;
(g) Prior art cited in Lumicore's P.R. 3-3 invalidity contentions, served October 14, 2024, comprising 23 prior-art references including patents, published patent applications, technical papers, and standards documents;
(h) Relevant technical literature and IEEE standards, including publications relating to coherent detection architectures, silicon-photonic integration methods, grating coupler design, and sub-wavelength photonic structures, as cited throughout this Appendix; and
(i) Lumicore product datasheets and marketing materials for the LumiLink 400G-ZR+, LumiLink 800G-DR8, and LumiEdge 1600G-LR, obtained through both public sources and document production in this litigation.
11.  A complete list of all materials reviewed in connection with both my main Expert Report and this Appendix is set forth in Exhibit 2 to the main Expert Report. I reserve the right to supplement that list and the opinions herein in light of any additional materials produced or made available subsequent to the date of this Appendix.
I.C. Summary of DOE Contentions
12.  The following table summarizes the three doctrine of equivalents contentions presented in this Appendix:
13.  It is important to emphasize that literal infringement is also asserted for each of these claims and accused products, as set forth in my main Expert Report and Appendix A. The doctrine of equivalents analysis in this Appendix provides an alternative basis for a finding of infringement in the event that the trier of fact determines that Lumicore's accused products do not literally satisfy one or more of the specific claim limitations identified above. The DOE contentions and the literal-infringement contentions are not mutually exclusive; they are presented in the alternative consistent with established patent litigation practice.
14.  The structure of this Appendix is as follows: Section II sets forth the governing legal framework for the doctrine of equivalents analysis; Sections III, IV, and V present the detailed DOE analysis for each of the three contentions; Section VI provides summary comparison tables and cross-references to annotated teardown photographs and design file excerpts; Section VII addresses anticipated counterarguments from Lumicore and its expert; and Section VIII states my conclusions.
II. LEGAL FRAMEWORK FOR DOCTRINE OF EQUIVALENTS ANALYSIS
15.  In preparing this Appendix, I have been instructed by counsel on the relevant legal principles governing the doctrine of equivalents. The following summary reflects my understanding of those principles as applied to the analysis herein.
II.A. The Function-Way-Result Test
16.  Under the doctrine of equivalents, a product or process that does not literally infringe a patent claim may nonetheless be found to infringe if, as to each limitation of the claim, the accused element performs substantially the same function, in substantially the same way, to achieve substantially the same result as the corresponding claim limitation. See Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605, 608 (1950); Warner-Jenkinson Co. v. Harborline Enterprises Davis Chem. Co., 520 U.S. 17, 39–40 (1997). This tripartite test — commonly known as the "function-way-result" test — is the principal analytical framework I have employed throughout this Appendix.
17.  Critically, the doctrine of equivalents is applied on an element-by-element basis, not to the claim as a whole. Warner-Jenkinson, 520 U.S. at 29. For each of the three DOE contentions in this Appendix, I have identified the specific claim limitation at issue and the specific corresponding element in Lumicore's accused products, and I have performed the function-way-result analysis with respect to that individual limitation. All other limitations of the asserted claims are met literally, as set forth in Appendix A.
18.  The relevant time frame for the equivalence inquiry is the time of infringement, not the time the patent was issued. See Warner-Jenkinson, 520 U.S. at 37. For purposes of this Appendix, the relevant time frames are as follows:
(a) For the LumiLink 400G-ZR+: Q3 2022 through the present, corresponding to the period from the product's commercial launch through the date of this report;
(b) For the LumiLink 800G-DR8: Q1 2023 through the present; and
(c) For the LumiEdge 1600G-LR: Q4 2023 through the present.
19.  As I explain in the detailed analyses below, the equivalence between the claimed elements and Lumicore's accused elements existed at the time each product was launched and continues through the present. The structural variations employed by Lumicore were well understood in the silicon photonics field at the time of infringement as interchangeable approaches to the same technological objectives achieved by the patented inventions.
II.B. Prosecution History Estoppel Considerations
20.  I understand that the doctrine of prosecution history estoppel may limit the scope of equivalents available to a patentee where the patentee narrowed a claim during prosecution to overcome a prior-art rejection. See Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002). Where a claim has been narrowed by amendment for reasons relating to patentability, there is a presumption that the patentee has surrendered the territory between the original claim scope and the amended claim scope. Id. at 740. However, this presumption may be rebutted if the patentee demonstrates that:
(a) the equivalent was unforeseeable at the time of the amendment;
(b) the rationale underlying the amendment bears only a tangential relation to the equivalent in question; or
(c) there is some other reason suggesting that the patentee could not reasonably be expected to have described the insubstantial substitute in question.
Festo, 535 U.S. at 740–41.
21.  Both the '193 Patent and the '015 Patent contain limitations that were narrowed during prosecution, and prosecution history estoppel is therefore a relevant consideration for each of the three DOE contentions in this Appendix. My analysis addresses estoppel as follows:
22.  Regarding the '193 Patent: During prosecution, the "coherent detection module" limitation at issue in Claims 3 and 7 was narrowed in a response filed to overcome a rejection under 35 U.S.C. § 102 based on Takahashi et al., "Dense WDM Silicon Photonic MUX," IEEE Photonics Technology Letters (March 2014). As I explain in detail in Sections III.D and IV.D below, the Festo presumption does not bar the DOE contentions asserted here because the narrowing amendment bears only a tangential relation to the equivalent at issue. The amendment was directed to distinguishing a non-coherent (direct-detection) receiver architecture disclosed in Takahashi; the structural variation in Lumicore's products concerns only the integration methodology of the local oscillator within a coherent receiver — a wholly separate technological characteristic that was not implicated by the Takahashi reference or the amendment made to overcome it. I understand that Calderwood & Harkness conducted a detailed prosecution history estoppel analysis for the '193 Patent, memorialized in an internal memorandum dated October 10, 2024, and I have reviewed that analysis in forming my opinions.
23.  Regarding the '015 Patent: Claim 12's "two-dimensional sub-wavelength grating" limitation was subject to a narrowing amendment during prosecution to overcome a rejection under 35 U.S.C. § 103 combining U.S. Patent No. 8,412,007 (Bergmann, issued April 2, 2013) with PCT/EP2015/071234 (Simonsen, published September 17, 2015). As I explain in detail in Section V.D below, the Festo tangential-relation exception applies because the amendment was directed to distinguishing prior-art grating structures that either lacked sub-wavelength features entirely (Bergmann) or lacked two-dimensional structuring (Simonsen), whereas Lumicore's accused grating structure does possess two-dimensional sub-wavelength features but differs only in the specific geometric profile and apodization of those features. I understand that Calderwood & Harkness's internal prosecution history estoppel analysis for the '015 Patent, dated October 12, 2024, reached the same conclusion.
II.C. All-Limitations Rule
24.  I further understand that the doctrine of equivalents must be applied in a manner that does not vitiate any claim limitation. See Brilliant Instruments, Inc. v. GuideTech, LLC, 707 F.3d 1342, 1347 (Fed. Cir. 2013). The all-limitations rule requires that the DOE analysis preserve meaningful content for every limitation of the asserted claim; a finding of equivalence cannot effectively read a limitation out of the claim. The question is whether the accused element is sufficiently similar to the claimed element that the limitation retains structural and functional significance, or whether the equivalence is so broad as to render the limitation meaningless.
25.  For each of the three DOE contentions in this Appendix, I have confirmed that the analysis does not vitiate any claim limitation. In each case, the accused equivalent element in Lumicore's products is structurally and functionally distinct from the prior art, possesses the core technological characteristics of the claimed element, and differs from the claimed element only in a specific, narrow structural variation. Meaningful scope remains for each claim limitation because structures that lack the core technological character of the claimed element — for example, non-coherent receivers (for the "coherent detection module" limitation) or gratings that lack two-dimensional sub-wavelength features (for the "two-dimensional sub-wavelength grating" limitation) — remain outside the scope of even the equivalents asserted here.
III. DOE ANALYSIS — '193 PATENT, CLAIM 3: "COHERENT DETECTION MODULE" LIMITATION
III.A. Claim Language and Context
III.A.1. Full Text of Claim 3
26.  U.S. Patent No. 10,891,193, titled "High-Bandwidth Coherent Optical Transceiver Integrated on Silicon Substrate," was filed on April 7, 2017, and issued on January 12, 2021. The '193 Patent claims priority to Provisional Application No. 62/499,117, filed April 7, 2017, which is a common priority document shared with the '015 Patent also asserted in this action. The named inventors are Dr. Jian-Wei Huang and Dr. Priya Ramanathan, both of whom are affiliated with OWS.
27.  Claim 3 of the '193 Patent depends from Claim 1. The full text of the relevant claims is reproduced below and is also attached as Exhibit B-1 to this Appendix:
28.  Claim 1 recites:
"An optical transceiver, comprising:
a silicon substrate;
a transmitter module integrated on the silicon substrate, the transmitter module comprising a laser source optically coupled to at least one Mach-Zehnder modulator configured to modulate an optical carrier signal with electrical data signals at a data rate of at least 100 Gbps per wavelength;
a receiver module integrated on the silicon substrate, the receiver module comprising a coherent detection module configured to recover phase and amplitude information from an incoming coherent optical signal;
a wavelength-division multiplexing element integrated on the silicon substrate; and
a control circuit electrically coupled to the transmitter module and the receiver module."
29.  Claim 3 recites:
"The optical transceiver of claim 1, wherein the coherent detection module comprises:
a local oscillator source integrated on the silicon substrate and configured to generate a reference optical signal;
a 90-degree optical hybrid coupler configured to mix the incoming coherent optical signal with the reference optical signal to produce at least four mixed optical output signals representing in-phase and quadrature components of the incoming coherent optical signal;
at least two pairs of balanced photodetectors, each pair configured to detect a respective in-phase or quadrature component of the mixed optical output signals; and
a transimpedance amplifier array electrically coupled to the balanced photodetectors."
30.  The limitation at issue for purposes of this DOE analysis is the "coherent detection module" as a whole as recited in Claim 3 — that is, the combination of the local oscillator source, the 90-degree optical hybrid coupler, the balanced photodetectors, and the transimpedance amplifier array, all of which are recited as components of the coherent detection module and are required to be "integrated on the silicon substrate."
III.A.2. Specification Support for "Coherent Detection Module"
31.  The '193 Patent specification provides extensive disclosure of the "coherent detection module" and its constituent components. As described in the specification at column 7, lines 14–58, and column 8, lines 1–35, and as illustrated in Figures 3A through 3D, the coherent detection module is an integrated optical receiver component designed to recover both phase and amplitude information from an incoming coherent optical signal. The specification explains that this is accomplished through local-oscillator mixing, in which the incoming signal is combined with a locally generated reference signal in a 90-degree optical hybrid coupler, followed by balanced photodetection of the resulting mixed signals and subsequent digital signal processing ("DSP") to recover the transmitted data.
32.  Figure 3A of the '193 Patent depicts the overall coherent detection module architecture, showing the local oscillator laser source (element 310), the 90-degree optical hybrid coupler (element 320), the two pairs of balanced photodetectors (elements 330a/330b and 330c/330d), and the transimpedance amplifier array (element 340), all fabricated on a silicon-on-insulator ("SOI") substrate. Figure 3B provides a more detailed schematic of the 90-degree optical hybrid coupler, showing its internal 2×4 multimode interference ("MMI") coupler structure. Figure 3C shows an SEM cross-section of the integrated local oscillator laser source, implemented as a III-V gain region heterogeneously integrated onto the silicon waveguide layer using a wafer-bonding approach. Figure 3D provides the detected signal constellation diagram demonstrating recovery of 16-QAM modulated data.
33.  The specification further explains at column 8, lines 12–35, that the monolithic integration of all coherent detection module components on the silicon substrate provides advantages in terms of reduced optical path lengths, improved phase stability between the signal and local oscillator arms, lower power consumption, and reduced manufacturing cost compared to discrete-component coherent receiver assemblies. The specification specifically states: "By integrating the local oscillator source, the optical hybrid, and the balanced photodetectors on a single silicon substrate, the coherent detection module of the present invention achieves unprecedented levels of phase stability and compactness, enabling deployment of coherent technology in pluggable transceiver form factors for the first time." ('193 Patent, col. 8, ll. 22–30.)
34.  With respect to the prosecution history narrowing, the prosecution of the '193 Patent proceeded as follows. As originally filed, Claim 1 recited a "receiver module" without specifying the type of detection employed. The examiner issued a non-final Office Action on March 12, 2019, rejecting Claims 1–10 under 35 U.S.C. § 102(a)(1) as anticipated by Takahashi et al., "Dense WDM Silicon Photonic MUX," IEEE Photonics Technology Letters, Vol. 26, No. 6, pp. 610–613 (March 2014). The Takahashi reference disclosed a silicon-photonic receiver module with a wavelength-division multiplexing element, but the receiver in Takahashi employed direct detection using PIN photodiodes, not coherent detection. In the applicant's response filed September 10, 2019, Claim 1 was amended to specify that the receiver module comprises "a coherent detection module configured to recover phase and amplitude information from an incoming coherent optical signal," thereby distinguishing the claim over Takahashi's direct-detection architecture. Dependent Claim 3, which further specifies the components of the coherent detection module, was added by amendment in the same response.
35.  Critically, the amendment that introduced the "coherent detection module" limitation was directed exclusively to distinguishing the fundamental detection methodology — coherent detection versus direct detection — and not to any particular integration approach for the components of the coherent detection module. The applicant's remarks filed with the September 10, 2019 amendment stated: "Takahashi's receiver employs PIN photodiodes for direct detection without any local-oscillator mixing. In contrast, amended Claim 1 now requires a 'coherent detection module configured to recover phase and amplitude information from an incoming signal optical signal,' which requires local-oscillator mixing and is fundamentally distinct from Takahashi's direct-detection approach." (Ex. B-3 at 12.) At no point during prosecution did the applicant discuss, distinguish, or disclaim any particular integration approach for the local oscillator or any other coherent detection module component.
III.A.3. Claim Construction Context
36.  The parties filed a Joint Claim Construction Statement pursuant to Patent Rule 4-3 on October 28, 2024, identifying 14 disputed claim terms across the '193 and '015 Patents. The term "coherent detection module" was not among the disputed terms; accordingly, neither party has proposed a construction that departs from its plain and ordinary meaning as understood by a POSITA.
37.  However, the related term "integrated on a silicon substrate," which appears in Claim 1 (from which Claim 3 depends) and qualifies the receiver module and its coherent detection module, is a disputed claim construction term. OWS proposes that "integrated on a silicon substrate" means "formed on or within a silicon-based wafer using semiconductor fabrication processes," which would encompass both monolithic integration and heterogeneous or hybrid integration techniques commonly used in silicon photonics (including, e.g., III-V semiconductor bonding, micro-transfer printing, and flip-chip bonding onto a silicon interposer). Lumicore proposes a narrower construction: "monolithically fabricated on a single silicon die without hybrid bonding or heterogeneous integration." Under Lumicore's proposed construction, a coherent detection module that includes a separately fabricated indium phosphide (InP) local oscillator attached to the silicon photonic chip via hybrid bonding would not be "integrated on a silicon substrate."
38.  The Markman hearing on claim construction is scheduled for March 14, 2025, before Judge Gilstrap. The Court's claim construction order has not yet issued as of the date of this Appendix. My DOE analysis is presented in a manner that addresses both possible construction outcomes. If the Court adopts OWS's proposed construction of "integrated on a silicon substrate," my opinion is that Lumicore's products literally satisfy the "coherent detection module" limitation, as set forth in the main Expert Report and Appendix A. If the Court adopts Lumicore's proposed construction, the DOE analysis in this Section III (and Section IV for Claim 7) provides an alternative basis for infringement, as the structural difference between the claimed and accused elements would relate only to the integration methodology of the local oscillator.
III.B. The Accused Element in Lumicore's Products
III.B.1. Technical Description of Lumicore's Detection Architecture
39.  Based on my review of the Benchmark Semiconductor Analysis, LLC teardown reports, Lumicore's design files and RTL schematics produced in discovery, and the deposition testimony of Dr. Sandra Michaud, I have determined the following with respect to the coherent detection architecture employed in the accused Lumicore products.
40.  LumiLink 400G-ZR+ (LL-400-ZRP-01). Kevin Ng's December 12, 2022 teardown report for the LumiLink 400G-ZR+ (OWS-BENCH-00001–00187) identified the coherent receiver subsystem as comprising the following components: (a) a silicon photonic integrated circuit ("Si-PIC") fabricated on an SOI substrate, containing waveguide routing, a 90-degree optical hybrid coupler implemented as a 2×4 MMI structure, and two pairs of germanium (Ge) balanced photodetectors monolithically integrated on the silicon die; (b) a separate indium phosphide (InP) distributed-feedback ("DFB") laser die functioning as the local oscillator source, micro-transfer-printed and bonded onto the surface of the Si-PIC using a gold-tin (AuSn) eutectic bonding process; and (c) a transimpedance amplifier ("TIA") array implemented as a separate SiGe BiCMOS integrated circuit, wire-bonded to the Si-PIC. The SEM images in the Benchmark report (OWS-BENCH-00067–00083) clearly show the InP DFB laser die bonded to the silicon photonic chip surface, with optical coupling achieved through an evanescent coupling structure fabricated in the silicon waveguide layer beneath the InP die.
41.  LumiLink 800G-DR8 (LL-800-DR8-02). Kevin Ng's June 2023 teardown report for the LumiLink 800G-DR8 (OWS-BENCH-00188–00412) confirmed that the 800G product employs the same fundamental coherent detection architecture as the LumiLink 400G-ZR+, with the following specific features: the Si-PIC contains eight parallel coherent receiver channels (compared to four in the 400G-ZR+ module), each channel comprising a 90-degree optical hybrid coupler and paired balanced Ge photodetectors; the local oscillator is again a separate InP DFB laser die bonded to the Si-PIC; and the TIA array is a 65nm CMOS IC, representing a process node upgrade from the SiGe BiCMOS TIA used in the 400G-ZR+. The SEM and optical micrograph data in the Benchmark report (OWS-BENCH-00245–00278) show the same hybrid-integration approach for the local oscillator.
42.  LumiEdge 1600G-LR (LE-1600-LR-03). Kevin Ng's February 2024 teardown report for the LumiEdge 1600G-LR (OWS-BENCH-00413–00679) confirmed that this newest product employs a similar but evolved version of the hybrid-integrated coherent detection architecture. Specifically, the LumiEdge module features sixteen parallel coherent receiver channels on the Si-PIC, a higher-power InP tunable laser as the local oscillator (also hybrid-bonded to the Si-PIC), an advanced 2×4 MMI hybrid coupler design optimized for the 1600G data rate, and a 7nm FinFET CMOS TIA. The local oscillator integration approach — hybrid bonding of a separate InP laser die onto the silicon photonic chip — is consistent across all three products.
43.  At deposition, Dr. Sandra Michaud, Lumicore's Chief Technology Officer, described the LumiLink/LumiEdge detection architecture and provided testimony relevant to this analysis. When asked about the function of the coherent detection module in the LumiLink 400G-ZR+, Dr. Michaud testified: "The coherent receiver in our LumiLink product performs coherent detection. It mixes the incoming signal with a local oscillator reference and uses balanced photodetectors to recover the in-phase and quadrature components. That's standard coherent detection." (Michaud Dep. Tr. 142:8–14.) When asked about the integration of the local oscillator, Dr. Michaud testified: "We chose to use a separately fabricated InP laser that is bonded to our silicon PIC. This is a hybrid integration approach. We considered monolithic approaches but determined that the InP DFB laser provided superior performance for our application in terms of linewidth and output power." (Michaud Dep. Tr. 148:3–11.)
44.  Dr. Michaud further confirmed that the hybrid-integration approach for the local oscillator was a design choice motivated by performance optimization, not by any fundamental difference in the detection methodology: "Whether the LO is monolithic or hybrid-bonded, the detection scheme is the same. You're mixing signal with LO in a 90-degree hybrid and detecting with balanced photodetectors. The integration method doesn't change the coherent detection principle." (Michaud Dep. Tr. 151:17–23.)
III.B.2. Identification of the Non-Literal Element
45.  The specific element in Lumicore's products that may not literally satisfy the "coherent detection module" limitation of Claim 3 — under Lumicore's proposed claim construction — is the local oscillator source. Claim 3 recites "a local oscillator source integrated on the silicon substrate and configured to generate a reference optical signal." The '193 Patent specification describes an embodiment in which the local oscillator laser is heterogeneously integrated onto the SOI substrate through a wafer-bonding process, with the III-V gain region formed directly on the silicon waveguide layer.
46.  Lumicore's products employ a local oscillator source that is fabricated as a separate InP DFB laser die and subsequently bonded to the surface of the silicon photonic chip using a micro-transfer-printing and AuSn eutectic bonding process. If the Court adopts Lumicore's proposed construction of "integrated on a silicon substrate" — which would require monolithic fabrication on a single silicon die without hybrid bonding or heterogeneous integration — then Lumicore's local oscillator would not literally satisfy this sub-element of the "coherent detection module" limitation.
47.  However, it is my opinion that even under Lumicore's proposed construction, the structural difference between the claimed and accused elements is insubstantial. The fundamental architecture of Lumicore's coherent detection module — local oscillator mixing, 90-degree optical hybrid coupling, balanced photodetection, and TIA amplification — is structurally and functionally the same as the claimed coherent detection module. The only difference is the specific integration method used to place the local oscillator laser on the silicon substrate: the patent specification primarily describes heterogeneous wafer bonding (in which the III-V material is bonded at the wafer level and then processed into laser structures on the silicon), while Lumicore uses micro-transfer printing of pre-fabricated InP laser dies (in which the InP laser is fabricated separately and then transferred and bonded to the silicon at the die level). Both approaches result in an InP-based local oscillator laser physically located on and optically coupled to the silicon photonic substrate.
III.C. Function-Way-Result Analysis
III.C.1. Substantially the Same Function
48.  The claimed "coherent detection module" of Claim 3 functions to recover phase and amplitude information from an incoming coherent optical signal for high-bandwidth data reception. Specifically, the coherent detection module generates a local oscillator reference signal, mixes the incoming signal with the reference signal in a 90-degree optical hybrid to produce in-phase (I) and quadrature (Q) components, detects those components using balanced photodetectors, and amplifies the resulting electrical signals for subsequent digital signal processing. The fundamental function is the coherent reception of optical data at high bandwidths (100 Gbps or more per wavelength) with preservation of both phase and amplitude information — capabilities that are absent in direct-detection receiver architectures.
49.  Lumicore's accused detection architecture in the LumiLink 400G-ZR+, LumiLink 800G-DR8, and LumiEdge 1600G-LR performs substantially the same function. Each product's coherent detection module generates a local oscillator reference signal (using the InP DFB laser), mixes the incoming signal with the reference signal in a 90-degree optical hybrid coupler, detects the I and Q components using balanced Ge photodetectors, and amplifies the resulting electrical signals through a TIA array. The function is identical: Coherent reception of optical data with phase and amplitude recovery.
50.  This functional identity is confirmed by multiple sources of evidence:
(a) Lumicore product datasheets. The datasheets for all three accused products describe their receiver subsystems as performing "coherent detection" with "phase and amplitude recovery" for "100G/200G/400G" (LumiLink 400G-ZR+), "800G" (LumiLink 800G-DR8), and "1600G" (LumiEdge 1600G-LR) data rates, respectively. The datasheets specifically reference "intradyne coherent reception" and "digital coherent processing."
(b) Dr. Michaud's deposition testimony. As quoted in paragraph 43 above, Dr. Michaud confirmed that the coherent receiver "performs coherent detection" by "mix[ing] the incoming signal with a local oscillator reference and us[ing] balanced photodetectors to recover the in-phase and quadrature components." (Michaud Dep. Tr. 142:8–14.)
(c) Benchmark teardown data. The Benchmark teardown reports for each product characterized the receiver subsystem as a "coherent intradyne receiver" performing "phase-diverse balanced detection." (OWS-BENCH-00089; OWS-BENCH-00256; OWS-BENCH-00498.)
51.  A POSITA would readily understand that the function of Lumicore's coherent detection module is substantially the same as the function of the claimed coherent detection module in Claim 3 of the '193 Patent. There is no meaningful functional difference.
III.C.2. Substantially the Same Way
52.  The claimed coherent detection module achieves its function through the following mechanism: a local oscillator source integrated on the silicon substrate generates a reference optical signal; a 90-degree optical hybrid coupler mixes the incoming coherent optical signal with the reference signal to produce at least four mixed optical output signals representing the I and Q components; balanced photodetectors detect the mixed signals; and a TIA array amplifies the resulting photocurrents. The critical aspect of the "way" in which the claimed element operates is the combination of intradyne local-oscillator mixing with balanced photodetection on a silicon photonic platform.
53.  Lumicore's accused products achieve the same function through the same core mechanism. The InP DFB local oscillator generates a reference optical signal that is coupled into the silicon waveguide layer through an evanescent coupling structure. The reference signal is then combined with the incoming signal in a 90-degree optical hybrid coupler (implemented as a 2×4 MMI structure, the same structure described in the '193 Patent specification). Balanced Ge photodetectors — monolithically integrated on the Si-PIC in all three products — detect the mixed I and Q optical signals. A TIA array amplifies the resulting photocurrents. The signal processing chain — local oscillator mixing, balanced detection, and transimpedance amplification — is functionally and mechanistically identical.
54.  The sole difference in the "way" relates to the integration approach for the local oscillator source: the '193 Patent specification describes heterogeneous wafer-level bonding of III-V material onto the SOI substrate, followed by lithographic patterning and processing of the laser structures; Lumicore uses micro-transfer printing of pre-fabricated InP DFB laser dies, followed by die-level bonding to the Si-PIC surface. Both approaches result in an InP-based laser physically situated on and optically coupled to the silicon photonic substrate. Both achieve optical coupling between the local oscillator output and the silicon waveguide through evanescent coupling structures. Both utilize the same wavelength stabilization and power control techniques. The difference is analogous to the difference between building a laser structure in situ on the silicon chip versus building it separately and then placing it on the silicon chip — the end result, in terms of the "way" the coherent detection is performed, is the same.
55.  A POSITA at the time of infringement (Q3 2022 through the present) would understand these as interchangeable approaches to coherent detection on silicon photonic platforms. The literature is replete with publications recognizing that hybrid integration (die bonding) and heterogeneous integration (wafer bonding) are alternative and functionally equivalent methods for placing III-V laser sources on silicon photonic substrates. See, e.g., T. Komljenovic et al., "Heterogeneous Silicon Photonic Integrated Circuits," J. Lightwave Technol., Vol. 34, No. 1, pp. 20–35 (Jan. 2016); G. Roelkens et al., "III-V-on-Silicon Integration for Coherent Transceivers," IEEE J. Sel. Topics Quantum Electron., Vol. 24, No. 1, Art. 6100112 (Jan./Feb. 2018). Both approaches are recognized in the industry as delivering comparable coherent detection performance when implemented on silicon photonic platforms.
56.  Supporting evidence from the Benchmark teardown data confirms the mechanistic equivalence. Kevin Ng's teardown reports for all three accused products include optical signal path analyses (OWS-BENCH-00091–00098; OWS-BENCH-00259–00267; OWS-BENCH-00502–00511) demonstrating that the signal flow through Lumicore's coherent detection module — from local oscillator output through the 90-degree hybrid to the balanced photodetectors — follows the same path topology as described in the '193 Patent specification.
57.  In his January 7, 2025 deposition, Kevin Ng confirmed: "The optical signal path in the Lumicore receiver is essentially the same as what you'd see in a standard intradyne coherent receiver architecture. The LO light enters a 90-degree hybrid, mixes with the signal, and balanced photodetectors measure the output. The only unique aspect is how the LO laser is attached to the PIC." (Ng Dep. Tr. 87:5–12.)
58.  Accordingly, it is my opinion that Lumicore's accused coherent detection module achieves its function in substantially the same way as the claimed coherent detection module of Claim 3.
III.C.3. Substantially the Same Result
59.  The claimed coherent detection module yields high-bandwidth coherent signal recovery with specified performance characteristics, including bit-error rate ("BER"), signal-to-noise ratio ("SNR"), and bandwidth sufficient for 100 Gbps or greater per-wavelength data reception with advanced modulation formats (e.g., DP-QPSK, DP-16QAM). The '193 Patent specification describes performance metrics achievable with the claimed coherent detection module architecture, including BER below 10⁻¹⁵ after forward error correction ("FEC") and an electrical signal bandwidth of at least 35 GHz per photodetector pair. (See '193 Patent, col. 9, ll. 4–22.)
60.  Lumicore's coherent detection module in each accused product yields substantially the same result:
(a) LumiLink 400G-ZR+: The Benchmark teardown report measured receiver sensitivity of −24 dBm at a pre-FEC BER of 4.2 × 10⁻³ for 400G DP-16QAM, with post-FEC BER below 10⁻¹⁵. The electrical bandwidth per photodetector pair was measured at approximately 38 GHz. (OWS-BENCH-00102–00107.) The Lumicore product datasheet specifies receiver sensitivity of −23 dBm and post-FEC BER below 10⁻¹⁵, consistent with the measured performance.
(b) LumiLink 800G-DR8: The Benchmark teardown report measured receiver sensitivity of −20 dBm at pre-FEC BER of 2.4 × 10⁻² for 800G operation (eight parallel 100G channels), with post-FEC BER below 10⁻¹⁵. The per-channel electrical bandwidth was approximately 36 GHz. (OWS-BENCH-00270–00278.)
(c) LumiEdge 1600G-LR: The Benchmark teardown report measured receiver sensitivity of −18 dBm at pre-FEC BER of 1.8 × 10⁻² for 1600G operation, with post-FEC BER below 10⁻¹⁵. The per-channel electrical bandwidth was approximately 42 GHz, reflecting the advanced 7nm CMOS TIA design. (OWS-BENCH-00515–00527.)
61.  These performance metrics fall within the same operational envelope described in the '193 Patent specification for the claimed coherent detection module. The BER, SNR, and bandwidth performance of Lumicore's detection modules is comparable to — and in some respects superior to — the performance of the embodiments described in the patent specification. This is consistent with the expectation that incremental improvements in semiconductor process technology over time would improve performance while maintaining the same fundamental detection architecture.
62.  The Lumicore specification sheets for all three products further confirm that the coherent detection results are substantially the same as those achieved by the claimed invention. The specifications describe "Coherent reception with phase and amplitude recovery," "support for DP-QPSK and DP-16QAM modulation formats," and "pluggable form factor deployment" — each of which corresponds to the results described in the '193 Patent specification as achievable with the claimed coherent detection module.
63.  Accordingly, it is my opinion that Lumicore's accused coherent detection module achieves substantially the same result as the claimed coherent detection module of Claim 3.
III.D. Prosecution History Estoppel — Inapplicability
III.D.1. Nature of the Prosecution Amendment
64.  As described in paragraph 34 above, during prosecution of the '193 Patent, the "coherent detection module" limitation was added to Claim 1 (and dependent Claim 3 was simultaneously added) in a response filed September 10, 2019, to overcome a § 102 rejection based on Takahashi et al. The Takahashi reference disclosed a silicon-photonic receiver module employing direct detection with PIN photodiodes for wavelength-demultiplexed intensity-modulated optical signals. Takahashi's receiver did not employ any local oscillator, did not include a 90-degree optical hybrid coupler, and did not perform coherent detection in any form.
65.  The applicant's amendment distinguished the claim from Takahashi by requiring a "coherent detection module configured to recover phase and amplitude information from an incoming coherent optical signal." The applicant's arguments in the September 10, 2019 response were entirely directed to the fundamental distinction between coherent detection and direct detection:
"Takahashi discloses a receiver module with PIN photodiodes for direct detection of intensity-modulated signals. Takahashi does not disclose, teach, or suggest a coherent detection module that recovers phase and amplitude information from a coherent optical signal. Direct detection, as practiced in Takahashi, inherently discards the phase information of the optical signal. In contrast, the amended claims require coherent detection, which preserves and recovers both phase and amplitude information. Accordingly, Takahashi fails to anticipate the amended claims."
(Exhibit B-3, Applicant's Response dated September 10, 2019, at pp. 11–13.)
66.  The amendment was not directed to, did not discuss, and did not distinguish any particular integration approach for the local oscillator source or any other component of the coherent detection module. The prosecution history contains no discussion of monolithic versus hybrid integration methods, no discussion of wafer-level versus die-level bonding, and no discussion of the physical arrangement of the local oscillator relative to the silicon substrate. The entirety of the prosecution distinction was between coherent and non-coherent detection.
III.D.2. Tangential Relation Exception Under *Festo*
67.  Under Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002), when a claim is narrowed by amendment for reasons related to patentability, there is a presumption that the patentee surrendered the territory between the original claim and the amended claim. However, this presumption may be rebutted where "the rationale underlying the amendment [bears] no more than a tangential relation to the equivalent in question." Id. at 740; see also Insituform Techs., Inc. v. CAT Contracting, Inc., 385 F.3d 1360, 1370 (Fed. Cir. 2004).
68.  The equivalent at issue in this analysis is the integration method of the local oscillator source within a coherent detection module. Specifically, the question is whether a coherent detection module with a hybrid-bonded InP local oscillator (Lumicore's approach) is equivalent to a coherent detection module with a monolithically integrated or heterogeneously bonded local oscillator (as described in the patent specification).
69.  The rationale for the prosecution amendment — distinguishing coherent detection from direct detection — bears only a tangential relation to the equivalent in question. The amendment was made to overcome a reference (Takahashi) that disclosed a fundamentally different detection paradigm — direct detection — that does not employ any local oscillator at all, regardless of how such a local oscillator might be integrated. The amendment said nothing about the integration method of the local oscillator because Takahashi's receiver did not have a local oscillator. The narrowing was in the dimension of detection methodology (coherent vs. direct), not in the dimension of integration methodology (monolithic vs. hybrid).
70.  A POSITA would not have foreseen that the amendment to require "coherent detection" would surrender coverage of hybrid-integrated coherent receivers. At the time of the amendment (September 2019), hybrid integration of III-V lasers onto silicon photonic chips was a well-known and widely practiced technique for building coherent receivers. A POSITA would have understood the amendment as directed to requiring any form of coherent detection — as opposed to direct detection — without regard to the specific integration approach used for the local oscillator. The concept of hybrid-bonded InP local oscillators on silicon photonic platforms was commercially available and extensively published in the literature by September 2019. See, e.g., Harborview Industries's commercial silicon photonic coherent transceivers, which employed hybrid-bonded InP lasers as of 2018; Ashbury & Co.'s (now Cisco's) hybrid silicon laser platform; and numerous academic publications on die-bonded III-V-on-silicon integration.
71.  Accordingly, the Festo tangential-relation exception is satisfied, and prosecution history estoppel does not bar the DOE contention for the "coherent detection module" limitation of Claim 3.
III.D.3. No Vitiation of the Limitation
72.  The DOE contention presented here does not vitiate the "coherent detection module" limitation of Claim 3. The claim limitation requires a coherent detection module with specific structural features: a local oscillator source, a 90-degree optical hybrid coupler, balanced photodetectors, and a TIA array, all integrated on a silicon substrate. Lumicore's accused element is still a coherent detection module with all of these structural features — it merely implements the local oscillator integration in a structurally non-identical manner (die-level hybrid bonding rather than wafer-level heterogeneous integration).
73.  Meaningful scope remains for the "coherent detection module" limitation even when the doctrine of equivalents is applied as I have described. Non-coherent receivers (such as Takahashi's direct-detection receiver) fall outside the scope of both the literal claim and the equivalents asserted here. Receiver architectures that lack a local oscillator, that do not employ balanced photodetection, or that do not use a 90-degree optical hybrid also remain outside the scope. Entirely different detection paradigms — such as self-coherent detection, Kramers-Kronig receivers, or Stokes-vector receivers — would likewise not be captured by the equivalents analysis. The limitation thus retains meaningful content; it is not vitiated by the narrow structural equivalence at issue.
IV. DOE ANALYSIS — '193 PATENT, CLAIM 7: "COHERENT DETECTION MODULE" LIMITATION
IV.A. Claim Language and Context
IV.A.1. Full Text of Claim 7
74.  Claim 7 of U.S. Patent No. 10,891,193 depends from Claim 3, which in turn depends from Claim 1. The full text of Claim 7 is reproduced below and is also attached as Exhibit B-1:
75.  Claim 7 recites:
"The optical transceiver of claim 3, wherein the coherent detection module further comprises:
a polarization beam splitter integrated on the silicon substrate and configured to separate incoming light into transverse-electric (TE) and transverse-magnetic (TM) polarization components;
a polarization rotator configured to rotate the TM polarization component to a TE polarization; and
dual 90-degree optical hybrid couplers, each configured to independently process a respective polarization component using the local oscillator source,
whereby the coherent detection module is configured for polarization-diverse coherent reception of a dual-polarization optical signal."
76.  Because Claim 7 depends from Claim 3 (which depends from Claim 1), Claim 7 includes all limitations of Claims 1 and 3 in addition to the limitations it recites independently. The "coherent detection module" element at issue in this Section IV is the same core element as in the Claim 3 analysis (Section III), but with the additional structural and functional requirements imposed by Claim 7's dependent limitations — specifically, the polarization beam splitter, the polarization rotator, and the dual 90-degree optical hybrid couplers configured for polarization-diverse coherent reception.
IV.A.2. Differences Between Claim 7 and Claim 3
77.  Claim 7 adds three specific limitations to the coherent detection module beyond those recited in Claim 3:
(a) A polarization beam splitter integrated on the silicon substrate that separates incoming light into TE and TM polarization components;
(b) A polarization rotator that converts the TM component to TE polarization, enabling both polarization components to be processed in the TE mode by the silicon waveguide structures (which are optimized for TE-mode propagation); and
(c) Dual 90-degree optical hybrid couplers, each independently processing one of the two polarization components using the same local oscillator source, enabling full polarization-diverse coherent reception.
78.  These additional limitations define a polarization-diversity receiver architecture, which is the standard architecture for receiving dual-polarization modulation formats such as DP-QPSK and DP-16QAM. The significance of these additional limitations for the DOE analysis is that they impose further structural and functional specificity on the coherent detection module, and the DOE analysis must address whether the accused products satisfy these additional requirements (literally or under DOE) in addition to the core "coherent detection module" limitation analyzed in Section III.
79.  For purposes of this Appendix, I note that the additional limitations recited in Claim 7 — the polarization beam splitter, polarization rotator, and dual optical hybrid couplers — are met literally by all three accused Lumicore products, as set forth in the main Expert Report and Appendix A (Claim Charts). The DOE analysis in this Section IV is directed to the same non-literal element identified in Section III — the integration method of the local oscillator source — as that element is the only element of Claim 7 for which DOE is required.
IV.B. The Accused Element in Lumicore's Products
80.  The accused products for Claim 7 are the same as for Claim 3: the LumiLink 400G-ZR+, LumiLink 800G-DR8, and LumiEdge 1600G-LR. The description of Lumicore's coherent detection architecture set forth in Section III.B above applies in full to the Claim 7 analysis and is incorporated here by reference.
81.  With respect to the additional limitations unique to Claim 7, the Benchmark teardown data confirms that each accused product includes the following components:
(a) Polarization beam splitter: The Benchmark teardown reports identified an on-chip polarization beam splitter in each product's Si-PIC, fabricated as a directional coupler-based PBS in the silicon waveguide layer. (OWS-BENCH-00085 (400G-ZR+); OWS-BENCH-00249 (800G-DR8); OWS-BENCH-00492 (1600G-LR).)
(b) Polarization rotator: Each product includes a silicon waveguide polarization rotator (a mode-evolution-based TM-to-TE converter) positioned after the PBS and before the optical hybrid for the TM channel. (OWS-BENCH-00086 (400G-ZR+); OWS-BENCH-00250 (800G-DR8); OWS-BENCH-00493 (1600G-LR).)
(c) Dual 90-degree optical hybrid couplers: Each product includes two 90-degree optical hybrid couplers (2×4 MMI structures), one processing the TE polarization component and one processing the rotated TM→TE component, both utilizing the same local oscillator source split by an on-chip power splitter. (OWS-BENCH-00087–00088 (400G-ZR+); OWS-BENCH-00251–00252 (800G-DR8); OWS-BENCH-00494–00495 (1600G-LR).)
82.  These components literally satisfy the corresponding limitations of Claim 7. The only non-literal element remains the local oscillator integration method, as described in Section III.B.2.
IV.C. Function-Way-Result Analysis
IV.C.1. Substantially the Same Function
83.  The core function of the coherent detection module as recited in Claim 7 is the same as in Claim 3 — recovery of phase and amplitude information from an incoming signal optical signal — with the additional function of performing this recovery in a polarization-diverse manner. Specifically, Claim 7's coherent detection module functions to: (i) separate the incoming dual-polarization signal into its TE and TM components; (ii) rotate the TM component to TE; (iii) independently process both polarization components through separate coherent detection channels using a shared local oscillator; and (iv) thereby enable polarization-diverse coherent reception of a DP-QPSK or DP-16QAM optical signal.
84.  Lumicore's accused coherent detection module performs substantially the same function. Each accused product's detection module separates the incoming signal into TE and TM polarization components, rotates TM to TE, independently processes both components through dual optical hybrid couplers with a shared local oscillator, and achieves polarization-diverse coherent reception. The additional function specified by Claim 7 — polarization-diverse coherent reception — is identical in Lumicore's products.
85.  Evidence supporting this conclusion includes: the Lumicore product datasheets for all three accused products, which specify "dual-polarization coherent reception" and support for "DP-QPSK" and "DP-16QAM" modulation formats; Dr. Michaud's deposition testimony, in which she confirmed that the LumiLink and LumiEdge receivers "receive and process both polarization components simultaneously using polarization-diversity architecture" (Michaud Dep. Tr. 156:4–9); and the Benchmark teardown reports, which identified and characterized all polarization-diversity components in each product.
IV.C.2. Substantially the Same Way
86.  The "way" in which Claim 7's coherent detection module achieves polarization-diverse coherent reception is through the specific combination of an on-chip polarization beam splitter, polarization rotator, and dual optical hybrid couplers sharing a common local oscillator on a silicon photonic substrate. Lumicore's products employ the same mechanism: the same types of on-chip polarization management components (PBS and rotator) and dual optical hybrid couplers sharing a common local oscillator, all on a silicon photonic substrate.

ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL

UNITED STATES DISTRICT COURT EASTERN DISTRICT OF TEXAS MARSHALL DIVISION

OPTIWAVE SEMICONDUCTOR CORP.,

LUMICORE TECHNOLOGIES, INC.,

EXPERT REPORT OF DR. CAROLINE ASHFORD

APPENDIX B: DOCTRINE OF EQUIVALENTS ANALYSIS

I. INTRODUCTION AND SCOPE

II. LEGAL FRAMEWORK FOR DOCTRINE OF EQUIVALENTS ANALYSIS

Record

Parties

Dates

Amounts