ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL NOT FOR DISCLOSURE OUTSIDE COUNSEL TEAM AND CLIENT WITHOUT PRIOR AUTHORIZATION
BENCHMARK TEARDOWN REPORT SUMMARY
LumiLink 400G-ZR+ Coherent Optical Transceiver Module
Supporting Exhibit to P.R. 3-1 Infringement Contentions
September 12, 2024
DESIGNATION: ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL This memorandum was prepared at the direction of counsel in anticipation of litigation and is protected by the attorney work-product doctrine. This document contains the mental impressions, conclusions, opinions, and legal theories of counsel for Optiwave Semiconductor Corp. It is not to be disclosed to any person or entity outside the attorney-client relationship without the express written authorization of Calderwood & Harkness LLP.
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I. EXECUTIVE SUMMARY
A. Purpose
This memorandum summarizes and annotates the teardown and reverse-engineering report prepared by Benchmark Semiconductor Analysis, LLC ("Benchmark") on the Lumicore Technologies, Inc. ("Lumicore") LumiLink 400G-ZR+ coherent optical transceiver module (the "Accused Product" or "400G-ZR+"). The underlying Benchmark report, dated December 12, 2022, was prepared by Kevin Ng, Lead Engineer at Benchmark, and constitutes a comprehensive physical teardown and reverse-engineering analysis of the 400G-ZR+ module. The purpose of this summary is to distill the factual findings of the Benchmark report and to provide a structured cross-reference of those findings to the claim limitations of the asserted patents in this matter, in support of Optiwave Semiconductor Corp.'s ("OWS" or "Plaintiff") Patent Rule 3-1 Infringement Contentions to be served on Lumicore on September 16, 2024.
This summary is cross-referenced to the claim limitations of three of the four asserted patents in this litigation, specifically: U.S. Patent No. 10,234,847 (the "'847 Patent"), U.S. Patent No. 10,891,193 (the "'193 Patent"), and U.S. Patent No. 9,678,562 (the "'562 Patent"). Together, these three patents address core silicon-photonic technologies relating to waveguide multiplexing, coherent transceiver integration, and thermal management of photonic integrated circuits, respectively.
It should be noted that the LumiLink 400G-ZR+ module is not accused of infringing U.S. Patent No. 11,402,015 (the "'015 Patent"), which issued on August 2, 2022, and whose claims are asserted exclusively against the LumiLink 800G-DR8 and LumiEdge 1600G-LR products. The '015 Patent pertains to polarization-diverse grating coupler structures that are the subject of separate teardown report summaries addressing those accused products. Accordingly, the discussion herein is confined to the '847, '193, and '562 Patents as they relate to the 400G-ZR+ module.
B. Background of Retention
The chain of events leading to the Benchmark teardown engagement began in the fall of 2022, shortly after Lumicore's commercial launch of the LumiLink 400G-ZR+ module during the third quarter of that year. OWS's internal engineering team, led by Dr. Nikolai Petrov, Vice President of Engineering, Photonics Division, identified potential infringement of OWS's patent portfolio in approximately October 2022. Dr. Petrov's team conducted a preliminary technical review of the 400G-ZR+ product based on Lumicore's publicly available datasheets, marketing materials, and technical white papers. This initial review flagged structural and functional characteristics of the 400G-ZR+ that appeared to correspond to several claims in the OWS patent portfolio.
The matter was promptly referred to Rebecca Tanaka, General Counsel of OWS, who engaged Calderwood & Harkness LLP for a more detailed infringement analysis. Following preliminary discussions with the litigation team, it was determined that a full physical teardown and reverse-engineering of the 400G-ZR+ module would be necessary to confirm the presence of the accused structures and to develop the technical record needed to support infringement contentions.
In November 2022, OWS retained Benchmark Semiconductor Analysis, LLC to perform a full physical teardown and reverse engineering of the LumiLink 400G-ZR+ module. Benchmark is a recognized semiconductor analysis firm specializing in reverse engineering, failure analysis, and competitive benchmarking of integrated circuits and photonic devices. Benchmark's lead engineer for this engagement was Kevin Ng, who has over fifteen years of experience in semiconductor reverse engineering and has previously performed teardown analyses that have been relied upon in patent-infringement litigation.
Benchmark delivered the completed teardown report on December 12, 2022. The report, comprising over 340 pages of analysis, images, measurements, and technical narrative, confirmed the presence of accused waveguide multiplexer structures, coherent transceiver architecture, and thermal management micro-channels matching the technologies claimed in the '847, '193, and '562 Patents. The Benchmark report has served as the technical foundation for all subsequent infringement analysis in this matter.
C. Key Findings (Summary)
The key physical and analytical findings from the Benchmark teardown report, as they relate to the asserted patents and the 400G-ZR+ module, are summarized as follows:
'847 Patent — Multi-Channel Silicon Photonic Waveguide Multiplexer. The LumiLink 400G-ZR+ module incorporates a multi-channel silicon photonic waveguide multiplexer structure fabricated on a silicon-on-insulator (SOI) substrate. The multiplexer structure, identified through scanning electron microscopy (SEM) and focused ion beam (FIB) cross-sectioning, combines multiple optical signals of different wavelengths onto a single output waveguide. The structural characteristics and performance parameters of this multiplexer correspond to the claims of the '847 Patent, including the low-insertion-loss design principles described in the patent specification.
'193 Patent — Coherent Optical Transceiver Integrated on Silicon Substrate. The module includes a coherent optical transceiver architecture — comprising modulator, local oscillator interface, balanced photodetector pairs, and in-phase/quadrature (I/Q) signal-processing components — that is integrated on a silicon photonic integrated circuit (PIC) substrate. This architecture is consistent with the high-bandwidth coherent optical transceiver described in the '193 Patent. The integration of these components on a single silicon substrate using CMOS-compatible fabrication processes directly corresponds to the architectural claims of the '193 Patent.
'562 Patent — Embedded Micro-Channel Heat-Sink Structures. The module utilizes embedded micro-channel heat-sink structures for thermal management of the photonic integrated circuit. FIB cross-sections and SEM imaging revealed micro-channels with hydraulic diameters ranging from approximately 60 µm to 170 µm, positioned beneath high-power-density regions of the PIC. These structures are consistent with the embedded micro-channel heat-sink methodology described in the '562 Patent, which was originally assigned to Solara Optics, Inc. and acquired by OWS pursuant to an asset purchase agreement dated June 15, 2018 for $34.5 million.
Revenue Context. According to Lumicore's segment disclosures and financial filings, fiscal year 2023 revenue for the LumiLink 400G-ZR+ was approximately $94.8 million. This figure is relevant to both the damages analysis and the willful-infringement arguments, as Lumicore continued to generate substantial revenue from this product after receiving actual notice of the asserted patents.
II. PRODUCT IDENTIFICATION AND SAMPLE ACQUISITION
A. Product Description
The accused product at issue in this teardown report summary is the LumiCore Technologies LumiLink 400G-ZR+ Coherent Optical Transceiver Module. The relevant product details are set forth below:
The LumiLink 400G-ZR+ is a pluggable coherent optical transceiver module designed for deployment in data-center interconnect (DCI) and metro networking environments. The QSFP-DD form factor is an industry-standard pluggable module specification that supports high-density deployment in network switches and routers. The 400G-ZR+ designation indicates compliance with the OIF (Optical Internetworking Forum) 400ZR and 400ZR+ implementation agreements, which define interoperable coherent optical interfaces at 400 Gbps line rates. The module is designed to support DWDM (Dense Wavelength Division Multiplexing) applications with reach capabilities suitable for metro and edge deployments.
The LumiLink 400G-ZR+ module is one of three Lumicore products accused of patent infringement in this action. The other two accused products — the LumiLink 800G-DR8 and the LumiEdge 1600G-LR — are addressed in separate teardown report summaries prepared in conjunction with subsequent Benchmark analyses.
B. Sample Acquisition Details
Sample units of the LumiLink 400G-ZR+ module were procured by OWS's engineering procurement team in November 2022 through commercial purchase channels. The units were purchased from an authorized distributor of Lumicore products. The acquisition was conducted at arm's length in the ordinary course of commerce, and the purchase price, invoice, and distributor identity are documented in OWS's internal procurement records, which have been produced in discovery.
Kevin Ng confirmed the chain of custody during his deposition on January 7, 2025. Specifically, Mr. Ng testified that the sample units were received at Benchmark's laboratory facility in Santa Clara, California; that each unit was logged with its respective serial number upon receipt; that each unit was photographed in its original packaging and in its unpackaged state prior to any analysis; and that all units were stored in a controlled-access facility at Benchmark's premises prior to the commencement of teardown activities. Mr. Ng further testified that the controlled-access storage area is limited to authorized Benchmark personnel and is monitored by electronic access-logging systems.
A total of three (3) units of the LumiLink 400G-ZR+ module were acquired for analysis. Two of the three units were subjected to destructive teardown procedures, as described in Section III below. The third unit was retained intact as a reference specimen, available for future non-destructive testing, functional verification, or presentation at trial. All three units remain in Benchmark's custody, and their continued integrity is documented in Benchmark's chain-of-custody log.
The serial numbers, lot codes, and date codes for all three units are documented in Benchmark Report Appendix A. These identifying data are not reproduced in this summary memorandum but are available in the produced documents at Bates numbers BSA-00001 through BSA-00047. The serial-number data confirms that the acquired units were manufactured during the initial production run of the 400G-ZR+ module in Q3 2022, consistent with the product's commercial launch timeline.
III. TEARDOWN METHODOLOGY
The Benchmark teardown followed a multi-stage methodology designed to systematically characterize the LumiLink 400G-ZR+ module from external form factor down to subsurface semiconductor structures. The methodology employed is consistent with established practices in the semiconductor reverse-engineering industry, as confirmed by Kevin Ng during his January 7, 2025 deposition. The principal stages of analysis are described below.
A. Bench-Level External Examination
The first stage of analysis consisted of a thorough external inspection of the 400G-ZR+ module. This included examination of the QSFP-DD form factor housing, the electrical connector interfaces, the optical port, and all external labeling. High-resolution photography was taken of all external surfaces, including the top and bottom faces of the module housing, the connector pin-out interfaces, and all regulatory, standards-compliance, and product-identification markings.
The external examination documented the module's compliance markings, including indicia of compliance with the QSFP-DD Multi-Source Agreement (MSA) mechanical specification and the Common Management Interface Specification (CMIS). These markings are relevant to confirming the product identity and the specific generation and variant of the module under analysis. The external labeling also confirmed the Lumicore product designation "LumiLink 400G-ZR+" and the corresponding model and part numbers, which match the product listings in Lumicore's commercial catalogs and datasheets.
B. Non-Destructive Analysis
Prior to any destructive disassembly, Benchmark performed a series of non-destructive analyses to characterize the internal architecture and functional performance of the module without compromising its physical integrity. These analyses included:
X-Ray Imaging. X-ray imaging was performed to visualize the internal module architecture, including the placement and interconnection of major components within the QSFP-DD housing. The X-ray images revealed the spatial arrangement of the silicon photonic integrated circuit (PIC) die, the digital signal processor (DSP) ASIC, the transimpedance amplifier (TIA), the laser driver integrated circuit, and the tunable laser assembly. The X-ray images also revealed the routing of electrical interconnects (wire bonds and/or flip-chip connections) and the general thermal-management architecture, including the position of heat spreaders and thermal interface materials. A total of twelve (12) X-ray images are included in the Benchmark report.
Functional Testing. Functional testing was performed on the optical and electrical interfaces of the module using calibrated test equipment. The module was powered and operated in accordance with its documented specifications, and the optical output characteristics — including center wavelength, linewidth, output power, modulation format, and signal-to-noise ratio — were measured. Electrical interface testing confirmed compliance with the QSFP-DD electrical specifications. These functional tests established baseline performance parameters that were subsequently correlated with the structural findings from the destructive teardown.
Optical Spectrum Analysis. Optical spectrum analysis was performed to characterize the wavelength channels and signal integrity of the module's optical output. This analysis confirmed the coherent modulation format and the wavelength characteristics of the module, which are relevant to understanding the operation of the internal waveguide multiplexer structure and the coherent transceiver architecture.
C. Destructive Teardown
Following the completion of non-destructive analysis, Benchmark proceeded with the controlled destructive disassembly of two of the three acquired sample units. The destructive teardown was performed in stages, progressing from macro-level disassembly of the module housing down to nanometer-scale cross-sectional analysis of the silicon PIC die.
Module Disassembly. The QSFP-DD housing was carefully opened under controlled conditions to access the internal subassemblies. The disassembly process was photographed at each stage to document the internal arrangement of components and the mechanical assembly techniques employed by Lumicore.
Component Identification and Removal. Individual discrete components were identified and removed for separate analysis. The principal components identified and removed include: (i) the digital signal processor (DSP) ASIC, which performs digital signal signal processing and forward error correction; (ii) the transimpedance amplifier (TIA), which converts photocurrent from the photodetectors to voltage signals; (iii) the laser driver integrated circuit, which modulates the drive current to the tunable laser; (iv) the tunable laser assembly, which provides the coherent optical carrier signal; and (v) the silicon photonic integrated circuit (PIC), which integrates the waveguide multiplexer, modulators, photodetectors, and grating coupler structures that are the primary focus of this infringement analysis.
Focused Ion Beam (FIB) Cross-Sectioning. FIB cross-sectioning was performed on the silicon PIC die to expose subsurface structural features that are not accessible through surface-level imaging. The FIB technique uses a focused beam of gallium ions to precisely mill cross-sections through the semiconductor die, allowing direct visualization of buried waveguide structures, metallization layers, and embedded micro-channel features. Multiple cross-sections were taken at strategically selected locations on the PIC die, targeting the waveguide multiplexer region, the modulator array, the photodetector array, and the thermal-management micro-channel structures. A total of thirty-four (34) FIB cross-section images are included in the Benchmark report.
Scanning Electron microscopy (SEM) Imaging. SEM imaging was performed extensively throughout the teardown process. SEM provides high-resolution surface and cross-sectional images at magnifications sufficient to resolve individual waveguide features, grating coupler elements, and micro-channel geometries. A total of eighty-seven (87) SEM images are included in the Benchmark report, covering the full range of structural features relevant to the asserted patents.
Energy-Dispersive X-Ray Spectroscopy (EDS). EDS analysis was performed to determine the material composition of specific structural features within the PIC die. Of particular relevance to the '562 Patent analysis, EDS was used to characterize the material composition of the micro-channel walls and passivation layers, confirming that the channels are formed in silicon with a thin silicon dioxide (SiO₂) passivation layer.
D. Analytical Methods
In addition to the imaging and cross-sectioning techniques described above, Benchmark employed several complementary analytical methods to quantify the structural and performance characteristics of the accused features:
Optical Profilometry. Optical profilometry was used to characterize the surface topology of waveguide structures on the PIC die. This technique provides three-dimensional surface-height measurements with sub-nanometer vertical resolution, enabling precise characterization of waveguide ridge heights, etch depths, and surface roughness — parameters that are relevant to the insertion-loss performance of the waveguide multiplexer and to the structural dimensions claimed in the '847 Patent.
Thermal Imaging (Infrared). Infrared thermal imaging was performed with the module operating under standard conditions to characterize heat dissipation pathways within the module. The thermal imaging captured temperature distributions across the PIC die surface during operation, identifying high-power-density regions and confirming the effectiveness of the embedded micro-channel heat-sink structures in removing heat from those regions. A total of eight (8) thermal imaging captures are included in the Benchmark report.
Dimensional Measurements. Precision dimensional measurements of micro-channel features — including channel width, channel depth, and calculated hydraulic diameter — were performed using SEM calibration standards. The calibration standards are NIST-traceable, and the calibration certificates for all instrumentation used in the analysis are included in Benchmark Report Appendix C.
Optical Probing. Optical probing measurements were taken on the waveguide multiplexer structure to characterize insertion-loss performance and spectral response. These measurements provide direct functional data that can be correlated with the structural features observed in the SEM and FIB cross-sections.
Kevin Ng confirmed the methodology and instrumentation described above during his January 7, 2025 deposition, testifying that these methods are standard in the semiconductor reverse-engineering industry and that the specific instrumentation used in the 400G-ZR+ teardown was properly calibrated at the time of analysis. Mr. Ng further testified that the methodology employed for this engagement was consistent with the methodology Benchmark has used in over 200 prior semiconductor teardown engagements.
IV. KEY PHYSICAL FINDINGS
This section summarizes the principal physical findings from the Benchmark teardown report that are relevant to the infringement analysis. The findings are organized by structural feature, corresponding to the categories of claims asserted in the three patents at issue.
A. Silicon Photonic Integrated Circuit (PIC) Architecture
The LumiLink 400G-ZR+ module contains a silicon photonic integrated circuit fabricated on a silicon-on-insulator (SOI) substrate. The SOI substrate is a standard platform for silicon photonics, consisting of a thin crystalline silicon device layer atop a buried silicon dioxide (SiO₂) insulator layer, which in turn sits on a bulk silicon handle wafer. The SOI platform exploits the high refractive-index contrast between silicon (n ≈ 3.48 at 1550 nm) and SiO₂ (n ≈ 1.44 at 1550 nm) to confine and guide light in compact waveguide structures.
The PIC integrates multiple functional blocks on a single die, including: (i) a wavelength multiplexer/demultiplexer for combining and separating optical channels; (ii) a modulator array for encoding data onto optical carriers; (iii) a photodetector array for detecting received optical signals; and (iv) grating coupler interfaces for coupling light between optical fibers and the on-chip waveguides. The monolithic integration of these functional blocks on a single silicon PIC die is a central feature of the 400G-ZR+ architecture and is directly relevant to the claims of the '193 Patent.
The PIC is manufactured using CMOS-compatible fabrication processes, consistent with semiconductor fabrication on a silicon-based wafer. This fabrication approach enables high-volume manufacturing in standard semiconductor foundries and is consistent with the fabrication methods described in the specifications of the asserted patents.
B. Multi-Channel Waveguide Multiplexer Structure
SEM and FIB cross-section imaging performed by Benchmark revealed a multi-channel arrayed waveguide structure within the PIC die. This structure is the central feature relevant to the '847 Patent claims.
The waveguide multiplexer is a planar photonic circuit that combines multiple optical signals of different wavelengths onto a single output waveguide. The structure employs a planar waveguide design consisting of a star coupler (also referred to as a slab region) connected to a phased array of individual waveguides with precisely controlled path-length differences. The path-length differences between adjacent waveguides in the array introduce wavelength-dependent phase shifts that cause constructive interference at the output coupler for each designated channel wavelength, thereby effecting the multiplexing function. This architecture is characteristic of an arrayed waveguide grating (AWG), which is the specific type of waveguide multiplexer described in the '847 Patent specification.
Benchmark measured the insertion-loss characteristics of the multiplexer structure through optical probing. The measured insertion-loss values are consistent with the low-insertion-loss design parameters described in the '847 Patent specification. The specific insertion-loss values, channel count, channel spacing (in GHz), center wavelengths, and free spectral range are documented in detail in Section 5.3 of the Benchmark report. These specific values are subject to the Highly Confidential — Attorneys' Eyes Only designation under the three-tier Stipulated Protective Order entered in this case and accordingly are not reproduced in this summary.
The SEM images of the multiplexer structure clearly resolve the individual waveguides in the phased array, the slab coupler regions at the input and output of the array, and the input/output channel waveguides. The FIB cross-sections reveal the waveguide cross-sectional geometry, including ridge height, etch depth, and cladding layer thicknesses. These dimensional parameters are relevant to the dependent claims of the '847 Patent (particularly Claims 3 and 5) and are discussed further in Section V below.
C. Coherent Transceiver Architecture
The 400G-ZR+ module implements a coherent detection architecture, which is the principal feature relevant to the '193 Patent claims. Coherent detection is an optical communication technique in which a received optical signal is mixed with a local oscillator (LO) signal to recover both the amplitude and phase information encoded on the carrier. The 400G-ZR+ module employs in-phase and quadrature (I/Q) signal processing, enabling the use of advanced modulation formats such as dual-polarization 16-QAM (DP-16QAM) at 400 Gbps.
Benchmark's teardown confirmed that the coherent optical transceiver components are integrated on the silicon PIC substrate. Specifically, the following functional elements were identified on the PIC die: (i) optical modulators (Mach-Zehnder interferometer-based) for encoding data onto the optical carrier; (ii) a local oscillator interface for mixing the received signal with the LO; (iii) balanced photodetector pairs for coherent signal detection; and (iv) optical hybrid structures for I/Q separation. These components collectively form the coherent transceiver front-end that is integrated on the silicon PIC die.
The DSP ASIC, which performs the digital signal signal processing functions (including carrier recovery, equalization, and forward error correction), is a separate die that is wire-bonded to the PIC. The DSP is not fabricated on the silicon PIC substrate but is electrically interconnected to it. This distinction is relevant to the claim-construction dispute regarding the term "integrated on a silicon substrate" in the '193 Patent, as discussed in Section VI below.
Benchmark also observed that the laser source — specifically, a tunable laser providing the coherent optical carrier — appears to employ a III-V compound semiconductor (e.g., indium phosphide, InP) gain medium that is bonded to the silicon PIC using a hybrid-integration or heterogeneous-integration technique. The laser-bonding interface is visible in SEM images and FIB cross-sections. This observation is relevant to the '193 Patent claim-construction dispute, as Lumicore's proposed construction of "integrated on a silicon substrate" would require "monolithic" fabrication and would exclude hybrid-bonded laser integration. OWS's proposed construction, which defines integration as "formed on or within a silicon-based wafer using semiconductor fabrication processes," encompasses the hybrid-integration approach observed in the 400G-ZR+ module.
D. Embedded Micro-Channel Heat-Sink Structures
FIB cross-sections and SEM imaging performed by Benchmark revealed embedded micro-channel structures within and beneath the silicon PIC die. These structures are the central feature relevant to the '562 Patent claims.
The micro-channels are oriented to remove heat from the high-power-density regions of the PIC, specifically the modulator array and the laser-coupling region. These regions generate significant heat during operation due to the power dissipated in driving the modulators and the thermal load associated with the bonded laser source. The micro-channels provide a direct thermal pathway for heat removal from these critical regions, enhancing the reliability and performance of the PIC.
Benchmark performed detailed dimensional measurements of the micro-channel structures using calibrated SEM imaging. The key dimensional parameters are as follows:
The hydraulic diameters are well within the sub-1 mm range specified in OWS's proposed construction of the term "micro-channel heat sink" and also fall within the narrower 10 µm to 200 µm range specified in Lumicore's proposed construction. The measurement methodology and detailed dimensional data are documented in Benchmark Report Section 6.2 and in the measurement data tables provided in Appendix E of the underlying report.
EDS analysis confirmed that the micro-channel walls are composed of silicon with a thin silicon dioxide (SiO₂) passivation layer. The oxide passivation layer is consistent with a fabrication process in which the channels are etched into the silicon substrate and subsequently thermally oxidized to provide a passivation and chemical barrier layer. This fabrication signature is consistent with the manufacturing methods described in the '562 Patent specification, particularly the steps recited in method Claim 11.
Benchmark further observed evidence of fluid (coolant) flow pathways and inlet/outlet manifold structures at the edges of the PIC die. These manifold structures are consistent with a liquid-cooling architecture in which a coolant fluid is circulated through the micro-channels to actively remove heat from the PIC. This observation is relevant to Lumicore's proposed construction of "micro-channel heat sink," which requires a "closed-loop liquid-cooling system." The presence of manifold structures at the die edges is consistent with such a closed-loop system, though the complete coolant circulation pathway (including external pump and heat exchanger) was not fully characterized in the Benchmark teardown because the destructive disassembly process necessarily disrupted the fluid-circuit connections.
Thermal imaging performed under operating conditions confirmed that the micro-channel structures provide effective heat dissipation. The infrared thermal images show reduced surface temperatures in the regions of the PIC die where the micro-channels are located, relative to adjacent regions without micro-channel structures. This thermal-performance data corroborates the structural evidence and demonstrates that the micro-channels are functional heat-management features, not merely artifacts of the fabrication process.
E. Grating Coupler Structures
SEM imaging identified grating coupler structures at the optical input/output (I/O) interfaces of the PIC die. Grating couplers are periodic diffractive structures etched into the silicon waveguide layer that couple light between optical fibers (oriented perpendicular or at a slight angle to the PIC surface) and the on-chip waveguides. The grating couplers in the 400G-ZR+ module provide the optical interface between the external fiber connections and the internal photonic circuits, including the waveguide multiplexer and the coherent transceiver components.
While the presence of grating couplers is relevant to the general architectural understanding of the PIC, detailed analysis of the polarization-handling characteristics of the 400G-ZR+ grating couplers was deferred to the subsequent teardowns of the LumiLink 800G-DR8 and LumiEdge 1600G-LR products. Those products are accused of infringing the '015 Patent, which claims polarization-diverse grating coupler structures. Because the LumiLink 400G-ZR+ is not accused of infringing the '015 Patent, a detailed polarization-diversity analysis of its grating couplers was not within the scope of this teardown engagement. The grating couplers are noted here solely for completeness and for their relevance to the overall PIC architectural characterization.
V. CLAIM-LIMITATION CROSS-REFERENCE ANALYSIS: '847 PATENT (U.S. PATENT NO. 10,234,847)
A. Patent Overview
The '847 Patent is directed to a multi-channel silicon photonic waveguide multiplexer designed to achieve low insertion loss. The relevant details of the patent are as follows:
The '847 Patent and the '562 Patent share a continuation relationship and are members of the same patent family. This familial relationship is relevant to the prosecution history and may bear on claim-construction arguments, as discussed in the respective claim-construction sections below.
Claims 1, 3, 5, and 9 are apparatus claims directed to the structure of the waveguide multiplexer. Claim 14 is a method claim directed to the manufacturing process for fabricating the multiplexer structure. Independent Claim 1 defines the multiplexer at the broadest level; Claims 3, 5, and 9 are dependent claims that add specific structural and functional limitations.
B. Claim 1 Cross-Reference
Independent Claim 1 of the '847 Patent defines a multi-channel silicon photonic waveguide multiplexer. The element-by-element mapping of each limitation of Claim 1 to the physical structures identified in the LumiLink 400G-ZR+ teardown is set forth below.
"Multi-channel." Benchmark confirmed the presence of multiple wavelength channels in the waveguide multiplexer structure within the PIC die. The specific channel count is documented in Section 5.3 of the Benchmark report and is consistent with a multi-channel architecture. The SEM images of the multiplexer input and output regions clearly show multiple distinct channel waveguides, each designed to carry a separate wavelength-division-multiplexed (WDM) optical signal. There is no dispute that the LumiLink 400G-ZR+ waveguide multiplexer is a "multi-channel" device.
"Silicon photonic waveguide multiplexer." The arrayed waveguide structure fabricated on the SOI PIC die is an optical device that combines multiple optical signals of different wavelengths onto a single waveguide. This structure was identified by Benchmark through SEM imaging and FIB cross-sectioning, as described in Section IV.B above. The multiplexer is fabricated in the silicon device layer of the SOI substrate, making it a "silicon photonic" device, and it performs the function of multiplexing — i.e., combining multiple optical channels onto a common waveguide path. This limitation is satisfied under OWS's proposed construction of "waveguide multiplexer" (defined as "an optical device that combines multiple optical signals of different wavelengths onto a single waveguide").
The term "waveguide multiplexer" is a disputed claim term in this case. OWS's and Lumicore's respective proposed constructions are discussed in Section V.F below. As noted there, the Benchmark teardown evidence supports a finding of infringement under either party's proposed construction.
"Low insertion loss." Benchmark performed optical probing measurements on the waveguide multiplexer structure and measured the insertion loss across the wavelength channels. The measured insertion-loss values are consistent with the low-insertion-loss design parameters described in the '847 Patent specification. The specific measurement data is documented in Section 5.3 of the Benchmark report and is subject to the Highly Confidential — Attorneys' Eyes Only designation under the Stipulated Protective Order. Under any reasonable interpretation of "low insertion loss" as informed by the patent specification, the measured performance of the 400G-ZR+ multiplexer satisfies this limitation.
Annotated photographs — specifically, SEM images with overlay markings identifying each claim element — are keyed to the claim-chart entries in the P.R. 3-1 Infringement Contentions. These annotated images reference Benchmark Report Figures 5.3-1 through 5.3-8, which depict the multiplexer structure at various magnifications and cross-sectional orientations.
C. Claims 3 and 5 Cross-Reference (Dependent Claims)
Claim 3. Dependent Claim 3 of the '847 Patent adds limitations relating to specific waveguide geometry and dimensional parameters of the multiplexer structure. Benchmark's SEM measurements of waveguide ridge height, waveguide width, etch depth, and inter-waveguide spacing in the phased array correspond to the dimensional parameters specified in Claim 3. The measurement data is documented in Section 5.4 of the Benchmark report, with supporting SEM images at calibrated magnifications. The dimensional correspondence between the teardown measurements and the claimed parameters supports infringement of Claim 3.
Claim 5. Dependent Claim 5 adds limitations relating to coupling efficiency characteristics of the multiplexer. Benchmark's optical probing data, which characterizes the spectral response and channel-to-channel uniformity of the multiplexer, supports the satisfaction of this limitation. The coupling efficiency data is derived from the insertion-loss and crosstalk measurements documented in Section 5.3 of the Benchmark report.
Note Regarding Claim Differentiation. During claim construction briefing, Lumicore has argued that independent Claim 1 should be construed narrowly in light of the additional limitations recited in dependent Claims 3 and 5. Specifically, Lumicore contends that because Claims 3 and 5 add specific dimensional and performance parameters, Claim 1 should not be read to encompass all waveguide multiplexer structures but should be limited to those satisfying some threshold geometric or performance criterion. OWS's claim-differentiation analysis, set forth in an internal memorandum dated October 8, 2024, rebuts this position by demonstrating that the doctrine of claim differentiation requires that each dependent claim be given scope beyond the independent claim, and that narrowing the independent claim to overlap with the dependent claims would violate this principle. In any event, the Benchmark teardown data satisfies both the independent and dependent claims, rendering the claim-differentiation dispute immaterial to the infringement analysis on this product.
D. Claim 9 Cross-Reference
Claim 9 of the '847 Patent contains a limitation that is potentially subject to means-plus-function treatment under 35 U.S.C. § 112(f). Pursuant to the internal means-plus-function analysis memorandum dated October 5, 2024, counsel has identified the relevant limitation and has determined that, if construed as a means-plus-function element, the corresponding structure disclosed in the '847 Patent specification can be identified with reasonable clarity.
The corresponding structure disclosed in the specification includes a specific waveguide taper and transition region that performs the recited function. Benchmark's teardown data identifies a structurally equivalent element in the LumiLink 400G-ZR+ PIC. Specifically, SEM images of the multiplexer region reveal a waveguide taper and transition structure at the identified location that is structurally equivalent to the disclosed corresponding structure. The structural equivalence analysis is supported by dimensional measurements showing comparable taper geometries and by the functional testing data confirming that the accused structure performs the same function as the disclosed structure. Whether construed as a means-plus-function limitation or under its plain and ordinary meaning, the teardown evidence supports infringement.
E. Claim 14 Cross-Reference
Claim 14 is a method claim directed to the process of manufacturing the multi-channel silicon photonic waveguide multiplexer. The method claim limitations are mapped to the manufacturing processes that can be inferred from the physical structures observed in the teardown. While the Benchmark teardown is, by its nature, a reverse-engineering analysis of the finished product rather than a direct observation of the manufacturing process, the physical characteristics of the structures provide strong circumstantial evidence of the fabrication steps that were employed.
Specifically, the FIB cross-sections of the waveguide multiplexer structure reveal etching patterns, layer deposition signatures, and material interfaces that are consistent with the fabrication steps recited in Claim 14. These include the formation of waveguide ridges through photolithographic patterning and reactive ion etching (RIE), the deposition of cladding layers, and the definition of the star coupler geometry. The etch profiles observed in the cross-sections — including sidewall angles and surface roughness characteristics — are indicative of the specific etching processes described in the patent specification. Gregory Falk, OWS's industry expert and former Vice President of Engineering at Solara Optics, Inc., is expected to provide testimony correlating these physical observations with the specific manufacturing processes recited in Claim 14.
F. Claim Construction Considerations
The central disputed claim term in the '847 Patent is "waveguide multiplexer." The parties' respective proposed constructions are as follows:
OWS's Proposed Construction: "an optical device that combines multiple optical signals of different wavelengths onto a single waveguide."
Lumicore's Proposed Construction: "an arrayed waveguide grating that combines optical signals using a slab coupler and phase-shifted waveguide array."
OWS's proposed construction is broader and encompasses any optical device — regardless of specific architecture — that performs the wavelength-combining function. Lumicore's proposed construction is narrower and limits the term to a specific type of waveguide multiplexer: an arrayed waveguide grating (AWG) that employs a slab coupler and a phase-shifted waveguide array.
Under either construction, the Benchmark teardown evidence supports a finding that the LumiLink 400G-ZR+ waveguide multiplexer satisfies this claim limitation. Under OWS's broader construction, the multiplexer structure clearly qualifies as "an optical device that combines multiple optical signals of different wavelengths onto a single waveguide," as confirmed by the SEM/FIB imaging and optical probing data. Under Lumicore's narrower construction, the analysis requires additional focus on the slab coupler and phased-array features of the multiplexer — both of which were specifically identified by Benchmark in the teardown. As described in Section IV.B above, Benchmark's SEM imaging resolved the slab coupler regions at the input and output of the waveguide array, and the phased array of individual waveguides with controlled path-length differences. Accordingly, even under Lumicore's proposed narrower construction, the accused structure satisfies the "waveguide multiplexer" limitation.
The claim-construction hearing (Markman hearing) is scheduled for March 14, 2025, before Judge James R. Gilstrap. Regardless of the outcome on this term, the Benchmark teardown evidence provides a strong evidentiary foundation for infringement.
VI. CLAIM-LIMITATION CROSS-REFERENCE ANALYSIS: '193 PATENT (U.S. PATENT NO. 10,891,193)
A. Patent Overview
The '193 Patent is directed to a high-bandwidth coherent optical transceiver integrated on a silicon substrate. The relevant details of the patent are as follows:
Claims 3 and 7 are asserted under both a theory of literal infringement and the doctrine of equivalents. Claims 1, 10, 15, and 18 are asserted under literal infringement only. The asserted claims include both apparatus claims (Claims 1, 3, 7, 10, and 15) and a method claim (Claim 18).
B. Claim 1 Cross-Reference
Independent Claim 1 of the '193 Patent defines a high-bandwidth coherent optical transceiver integrated on a silicon substrate. The element-by-element mapping of each limitation of Claim 1 to the 400G-ZR+ teardown findings is set forth below.
"High-bandwidth." The LumiLink 400G-ZR+ operates at a data rate of 400 Gbps, which constitutes a "high-bandwidth" coherent optical transceiver by any measure. The 400 Gbps data rate is confirmed by Benchmark's functional testing and by Lumicore's own product specifications and datasheets. There is no serious dispute that this limitation is satisfied.
"Coherent optical transceiver." Benchmark confirmed that the 400G-ZR+ implements a coherent detection architecture with I/Q signal processing, a local oscillator interface, and balanced photodetector pairs. The coherent transceiver architecture was identified through both functional testing (which confirmed the coherent modulation format) and structural analysis (which revealed the optical hybrid, balanced photodetector, and modulator structures on the PIC die). The term "coherent optical transceiver" is not a disputed claim term, and the Benchmark findings leave no doubt that this limitation is satisfied.
"Integrated on a silicon substrate." Benchmark confirmed that the coherent optical transceiver functional blocks — including modulators, local oscillator interface, balanced photodetectors, and optical hybrids — are formed on the SOI PIC die. The silicon PIC is fabricated using CMOS-compatible semiconductor fabrication processes, and the transceiver components are integrated on the silicon substrate of the SOI wafer.
The term "integrated on a silicon substrate" is a disputed claim term. The parties' respective proposed constructions are:
OWS's Proposed Construction: "formed on or within a silicon-based wafer using semiconductor fabrication processes."
Lumicore's Proposed Construction: "monolithically fabricated on a single silicon die without hybrid bonding or heterogeneous integration."
This dispute is of significant consequence because, as described in Section IV.C above, Benchmark observed that the laser source in the 400G-ZR+ module appears to employ a III-V compound semiconductor (likely indium phosphide) gain medium that is bonded to the silicon PIC using a hybrid-integration technique. If the laser source is considered part of the "transceiver" as claimed, Lumicore's proposed construction — which excludes hybrid bonding — could potentially narrow the scope of the claim to exclude the accused structure.
Under OWS's proposed construction, the accused structure clearly satisfies this limitation because the primary transceiver components (modulators, photodetectors, optical hybrids, and waveguide interconnects) are formed on or within the silicon-based SOI wafer using semiconductor fabrication processes. The fact that the laser gain medium is separately fabricated in a III-V material system and then bonded to the silicon PIC does not negate the integration of the transceiver components on the silicon substrate.
Under Lumicore's narrower construction, the laser-bonding interface raises an issue that requires further analysis. OWS's position is that the laser source is not part of the "transceiver" as claimed in Claim 1. The claim language distinguishes between the transceiver — which performs the modulation, detection, and signal-processing functions — and the laser source, which provides the optical carrier. Under this reading, the transceiver components are monolithically fabricated on the silicon PIC die, and the laser bonding is irrelevant to the claim limitation. This position is supported by the '193 Patent specification, which describes the laser as a separate element that interfaces with the transceiver circuit.
This issue will be addressed in detail in OWS's claim-construction brief, with supporting expert testimony from Dr. Caroline Ashford.
C. Claims 3 and 7 — Literal and Doctrine of Equivalents Analysis
Claim 3.  Claim 3 of the '193 Patent is a dependent claim that adds a "coherent detection module" limitation. Benchmark identified a coherent detection module within the PIC die, comprising the optical hybrid structures and balanced photodetector pairs that perform the coherent mixing and detection functions.
Prosecution History Considerations. During prosecution of the '193 Patent, the "coherent detection module" limitation was narrowed in response to a § 102(a)(1) prior-art rejection based on Takahashi et al. (published in IEEE Photonics Technology Letters, March 2014). The prosecution amendment narrowed the claim scope by adding specific structural requirements for the coherent detection module that distinguished the claimed invention over Takahashi. This prosecution-history amendment implicates the doctrine of prosecution history estoppel under Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002), which creates a presumption that the patentee has surrendered equivalents within the narrowing amendment.
An internal memorandum dated October 10, 2024 assesses the Festo presumption and its applicability to Claim 3 in the context of the 400G-ZR+ teardown evidence. The memorandum concludes that the tangential-relation exception to the Festo presumption may apply in this case. The tangential-relation exception provides that estoppel does not bar a doctrine-of-equivalents argument where the rationale underlying the narrowing amendment was merely tangentially related to the equivalent at issue. Here, the prosecution amendment was directed to distinguishing the structural arrangement of the detection module from the discrete-component arrangement of Takahashi, not to exclude the specific variant of coherent detection architecture employed in the 400G-ZR+ module. Accordingly, the tangential-relation exception preserves the doctrine-of-equivalents theory for Claim 3.
Literal Infringement. Under the literal-infringement theory, the Benchmark teardown data shows that the accused coherent detection module in the 400G-ZR+ PIC falls within the narrowed claim scope. The structural features added by the prosecution amendment are present in the accused structure, as confirmed by SEM imaging and FIB cross-sections.
Doctrine of Equivalents. Under the doctrine of equivalents, applying the function-way-result test: even if the accused design employs a variant detection architecture that differs in some respects from the literal claim language, it performs substantially the same function (coherent detection of optical signals), in substantially the same way (using balanced photodetection with I/Q separation to recover signal information), to achieve substantially the same result (recovery of amplitude, phase, and polarization information from the optical signal). The Benchmark teardown data provides the structural and functional evidence necessary to support this analysis.
Claim 7.  Claim 7 is an additional dependent claim that adds a further limitation related to the coherent transceiver architecture. Like Claim 3, Claim 7 is asserted under both literal infringement and the doctrine of equivalents. The teardown evidence supports both theories for Claim 7. The detailed function-way-result analysis for the doctrine-of-equivalents contentions on Claims 3 and 7 is set forth in Dr. Caroline Ashford's draft infringement report, Appendix B: DOE Analysis, which provides a comprehensive element-by-element equivalents analysis supported by the Benchmark teardown data.
D. Claim 10 Cross-Reference
Claim 10 of the '193 Patent adds limitations relating to specific modulator and photodetector configurations within the coherent transceiver. Benchmark's teardown identified the specific modulator type (Mach-Zehnder interferometer-based modulators) and photodetector configuration (balanced photodetector pairs) on the 400G-ZR+ PIC die. Annotated SEM images showing the modulator and photodetector structures, with overlay markings keyed to each element of Claim 10, are referenced in the P.R. 3-1 Infringement Contentions and are derived from Benchmark Report Figures 4.2-1 through 4.2-6 and 4.4-1 through 4.4-4.
The modulator array consists of multiple Mach-Zehnder interferometer (MZI) structures arranged in a nested I/Q configuration, consistent with the modulator architecture described in the '193 Patent specification. The photodetectors are germanium-on-silicon (Ge-on-Si) photodiodes configured in balanced pairs, providing the differential detection required for coherent reception. These structural observations are consistent with the limitations of Claim 10 and support a finding of literal infringement.
E. Claim 15 Cross-Reference
Claim 15 of the '193 Patent contains a term that is potentially subject to means-plus-function treatment under 35 U.S.C. § 112(f), as identified in the internal means-plus-function analysis memorandum dated October 5, 2024. The potentially means-plus-function term uses functional language that invokes the presumption of § 112(f) application.
Counsel has identified the corresponding structure disclosed in the '193 Patent specification for the means-plus-function limitation. The corresponding structure comprises a specific signal-conditioning circuit arrangement described in the specification and illustrated in the patent drawings. Benchmark's teardown data demonstrates the presence of structurally equivalent elements in the LumiLink 400G-ZR+ PIC die. The structural equivalence is confirmed by SEM imaging showing a circuit layout with comparable functional blocks and interconnect routing, and by functional testing data confirming that the accused structure performs the same function recited in the claim limitation.
F. Claim 18 Cross-Reference
Claim 18 is a method claim directed to the signal processing and transceiver operation of the coherent optical transceiver. The method claim limitations are mapped to the operational processes inferred from the functional testing and structural analysis conducted by Benchmark. The functional testing confirmed that the 400G-ZR+ module performs coherent optical signal processing consistent with the method steps recited in Claim 18, including the steps of modulating, transmitting, receiving, coherently detecting, and digitally processing optical signals at 400 Gbps using the integrated silicon photonic transceiver architecture.
While direct observation of the method steps during operation is not possible through a teardown analysis alone, the structural evidence combined with the functional testing data provides a strong basis for inferring that the module, when operated in its intended manner (as documented in Lumicore's own datasheets and application notes), practices each step of the claimed method.
VII. CLAIM-LIMITATION CROSS-REFERENCE ANALYSIS: '562 PATENT (U.S. PATENT NO. 9,678,562)
A. Patent Overview
The '562 Patent is directed to a method for thermal management of photonic integrated circuits using embedded micro-channel heat sinks. The relevant details of the patent are as follows:
The '562 Patent was originally assigned to Solara Optics, Inc., a California corporation that was dissolved in 2020. OWS acquired the '562 Patent, along with eleven other patents from the Solara portfolio, pursuant to an Asset Purchase Agreement dated June 15, 2018. The total consideration for the asset acquisition was $34.5 million. The assignment was duly recorded with the United States Patent and Trademark Office, and OWS is the current owner of record for the '562 Patent. The chain of title is documented in the assignment records produced in this litigation.
As noted in Section V.A above, the '562 Patent and the '847 Patent are in the same patent family and share a continuation relationship. This relationship is relevant to the prosecution-history analysis and to the consistency of claim constructions across the two patents.
Claims 1, 4, and 6 are apparatus claims directed to the micro-channel heat-sink structure and its configuration relative to the PIC. Claim 11 is a method claim directed to the fabrication process for embedding the micro-channels within the PIC substrate.
B. Claim 1 Cross-Reference
Independent Claim 1 of the '562 Patent defines an embedded micro-channel heat-sink structure for a photonic integrated circuit. The element-by-element mapping of each limitation of Claim 1 to the 400G-ZR+ teardown findings is set forth below.
"Photonic integrated circuit." The silicon PIC in the LumiLink 400G-ZR+ module is a photonic integrated circuit within the meaning of the claim. The PIC integrates multiple photonic functional blocks — including waveguides, modulators, photodetectors, and grating couplers — on a single silicon substrate. There is no dispute that the 400G-ZR+ PIC is a "photonic integrated circuit."
"Embedded micro-channel heat sinks." FIB cross-sections and SEM images obtained by Benchmark reveal channels embedded within and beneath the PIC die. The channels are formed in the silicon substrate material and are enclosed by the surrounding silicon structure and the passivation layer. The channels are "embedded" in the sense that they are contained within the body of the semiconductor die rather than being external surface-mounted heat-dissipation structures. The structural features observed in the teardown are consistent with the "embedded micro-channel heat sinks" described and claimed in the '562 Patent.
"Micro-channel heat sink" — this is a disputed claim term. The parties' respective proposed constructions are:
OWS's Proposed Construction: "a heat-dissipating structure containing channels with a hydraulic diameter of less than 1 mm."
Lumicore's Proposed Construction: "a closed-loop liquid-cooling system with channels having a hydraulic diameter between 10 µm and 200 µm."
The Benchmark measurements provide critical data on this dispute. The measured hydraulic diameters of the micro-channels — approximately 60 µm to 170 µm — fall within both parties' proposed dimensional ranges. Under OWS's broader construction, the structures clearly qualify because the hydraulic diameters are well below 1 mm. Under Lumicore's narrower construction, the structures also satisfy the dimensional requirements (60–170 µm falls within the 10–200 µm range), but Lumicore's construction adds an additional functional element — the requirement that the micro-channels be part of a "closed-loop liquid-cooling system."
With respect to the "closed-loop liquid-cooling system" element of Lumicore's proposed construction, Benchmark observed evidence of fluid flow pathways and inlet/outlet manifold structures at the die edges, as described in Section IV.D above. These structural features are consistent with a liquid-cooling system in which coolant is circulated through the micro-channels. While the complete external coolant loop (pump, reservoir, and heat exchanger) was not characterized during the teardown — because the destructive disassembly process necessarily severed the fluid connections — the on-die manifold structures provide strong evidence of a liquid-cooling architecture. OWS contends that Lumicore's proposed construction improperly imports a "closed-loop" limitation from the specification that is not present in the claim language. In any event, the structural evidence supports the inference that the 400G-ZR+ micro-channels are part of a liquid-cooling system.
Thermal imaging under operating conditions confirmed effective heat dissipation through the micro-channel structures, as described in Section IV.D above. This functional evidence further supports the conclusion that the micro-channels operate as "heat sinks" within the meaning of the claims.
C. Claim 4 Cross-Reference
Dependent Claim 4 of the '562 Patent specifies dimensional parameters for the micro-channels, including ranges for channel width, channel depth, and/or hydraulic diameter. Benchmark's measurements of the 400G-ZR+ micro-channels — channel widths of approximately 50 µm to 150 µm and channel depths of approximately 80 µm to 200 µm — correspond to the dimensional ranges specified in Claim 4. The detailed measurement data, including measurement locations, sample sizes, and statistical distributions, is documented in Benchmark Report Section 6.2 and in the measurement data tables provided in Appendix E of the underlying report. The correspondence between the measured dimensions and the claimed ranges is direct and supports literal infringement of Claim 4.
D. Claim 6 Cross-Reference
Dependent Claim 6 of the '562 Patent addresses the orientation and spatial distribution of the micro-channels relative to the heat-generating regions of the PIC. Specifically, Claim 6 requires that the micro-channels be positioned beneath or adjacent to the highest-power-density functional blocks of the photonic integrated circuit.
Benchmark's thermal imaging data, overlaid with micro-channel location mapping derived from SEM and FIB cross-sections, confirms that the micro-channels in the 400G-ZR+ PIC are positioned beneath and adjacent to the modulator array and the laser-coupling region. These regions were independently confirmed to be the highe