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Contract analysis Extract to table

CALDERWOOD & HARKNESS LLP Attorneys at Law

March 8, 2024

Benchmark Teardown Report Summary — LumiEdge 1600G-LR

INTERNAL ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL

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I. EXECUTIVE SUMMARY

Purpose. This memorandum summarizes and analyzes the teardown report prepared by Benchmark Semiconductor Analysis, LLC ("Benchmark") for the Lumicore Technologies, Inc. ("Lumicore") LumiEdge 1600G-LR optical transceiver module. The memorandum cross-references the teardown findings to the claim limitations of the two asserted patents relevant to this product: U.S. Patent No. 10,891,193 (the "'193 Patent") and U.S. Patent No. 11,402,015 (the "'015 Patent"). This document is intended to serve as a working reference for the litigation team and to facilitate preparation of expert reports, infringement contentions supplements, and trial demonstratives.

Teardown Lab. The teardown was conducted by Benchmark Semiconductor Analysis, LLC, located at 2244 Mission College Boulevard, Santa Clara, CA 95054. The lead engineer for this teardown was Kevin Ng, who has served as Benchmark's lead engineer for all three teardowns conducted in this matter. Mr. Ng holds a Ph.D. in Electrical Engineering from Stanford University and has over fifteen years of experience in semiconductor failure analysis and reverse engineering.

Date of Teardown Report Delivery. Benchmark delivered its final teardown report for the LumiEdge 1600G-LR in February 2024. This is the third and most recent teardown conducted by Benchmark in this matter. The prior teardowns were as follows:

1. LumiLink 400G-ZR+ — Report delivered December 12, 2022. This was the first teardown commissioned in the matter and supported the original infringement analysis that led to the filing of this action.

2. LumiLink 800G-DR8 — Report delivered June 2023. This teardown was commissioned after Lumicore launched the 800G-DR8 product and Optiwave Semiconductor Corp. ("OWS") identified it as an additional accused product.

3. LumiEdge 1600G-LR — Report delivered February 2024. This teardown is the subject of this memorandum.

Product Examined. The product examined was the LumiEdge 1600G-LR transceiver module, manufactured and sold by Lumicore Technologies, Inc. (headquarters: 9200 Spectrum Boulevard, Building C, Austin, TX 78759). The LumiEdge 1600G-LR was launched in Q4 2023 and represents Lumicore's flagship coherent transceiver offering, targeting hyperscale data-center interconnect and long-haul telecom applications. Per Lumicore's most recent segment disclosures filed with the Securities and Exchange Commission, the LumiEdge 1600G-LR generated estimated FY 2023 revenue of $41.7 million. This figure represents a partial-year revenue amount given the product's Q4 2023 launch, and revenue is expected to grow substantially through the projected trial date.

Key Conclusion. The teardown confirms the presence of structures and functional elements in the LumiEdge 1600G-LR that correspond to the asserted claim limitations of the '193 Patent (Claims 1, 3, 7, 10, 15, 18) and the '015 Patent (Claims 1, 5, 8, 12, 16). Of particular note:

• The product incorporates a polarization-diverse grating coupler structure that is central to the infringement analysis for the '015 Patent. SEM imagery at multiple magnifications reveals a grating geometry consistent with the claimed structures, including features relevant to the disputed "polarization-diverse grating coupler" claim construction term.

• The product incorporates a coherent optical transceiver architecture integrated on a silicon substrate that maps to the '193 Patent claims. Cross-sectional analysis and material composition testing confirm that the transceiver optical engine is formed on a silicon-based wafer using semiconductor fabrication processes, directly implicating the disputed "integrated on a silicon substrate" claim construction term.

• The LumiEdge 1600G-LR's silicon photonic integrated circuit ("PIC") die incorporates both the coherent transceiver engine and the grating coupler structures on the same photonic chip, demonstrating the integration of the patented innovations within a single product.

Doctrine of Equivalents Relevance. This teardown is particularly important for the doctrine of equivalents ("DOE") analysis pertaining to Claims 3 and 7 of the '193 Patent (regarding the "coherent detection module" limitation) and Claim 12 of the '015 Patent (regarding the "two-dimensional sub-wavelength grating" limitation). The LumiEdge 1600G-LR uses design variants that may not literally satisfy certain claim limitations but that perform substantially the same function, in substantially the same way, to achieve substantially the same result. The DOE analysis is discussed in detail in Sections IV.C and V.D below, and cross-references to the applicable prosecution history estoppel analyses are provided therein.

Note on Product Timing. The LumiEdge 1600G-LR was launched after Lumicore received both FairPoint Licensing Group, LLC's first licensing letter (dated January 15, 2023, identifying the '847, '193, and '562 Patents) and second licensing letter (dated May 15, 2023, adding the '015 Patent and expanding the list of accused products). Lumicore formally declined to take a license on July 10, 2023, stating that it had obtained "competent legal opinions" that its products do not infringe. Despite this notice, Lumicore proceeded to launch the LumiEdge 1600G-LR in Q4 2023. Lumicore's decision to launch this product despite actual notice of the asserted patents is relevant to the willful infringement analysis under Halo Electronics, Inc. v. Pulse Electronics, Inc., 579 U.S. 93 (2016), and OWS's request for enhanced damages under 35 U.S.C. § 284. This issue is discussed in further detail in Section VIII.B below.

II. BACKGROUND AND CHAIN OF CUSTODY

A. Product Acquisition

The LumiEdge 1600G-LR sample units examined in the Benchmark teardown were acquired through commercial distribution channels to ensure the authenticity and provenance of the product. Calderwood & Harkness LLP, on behalf of OWS, directed the acquisition of three (3) sealed LumiEdge 1600G-LR transceiver modules in late Q4 2023, shortly following the product's commercial launch. The modules were purchased from Horizon Network Supply, Inc., an authorized Lumicore distributor, on December 18, 2023. A fourth unit was subsequently purchased on January 9, 2024, from a separate authorized distributor, DataPath Components Group, LLC, to provide redundancy and ensure that the initial units were representative of commercially available product.

All four units were shipped directly to Benchmark's controlled-access laboratory in Santa Clara, California. Upon receipt, Benchmark recorded the serial numbers, lot numbers, and date codes for each unit. The specific identifiers for the primary teardown unit (designated "Unit TD-01") are as follows:

• Serial Number: LME-1600LR-2023Q4-0041827

• Lot Number: LT-2023-1109-A3

• Date Code: 2347 (indicating Week 47, 2023 manufacture)

• Purchase Source: Horizon Network Supply, Inc. (Invoice No. HNS-2023-18742)

• Date of Purchase: December 18, 2023

• Date of Receipt at Benchmark: December 22, 2023

Product packaging, labeling, marketing materials, and accompanying technical documentation (including the Lumicore LumiEdge 1600G-LR Product Brief, Rev. 1.2, and the LumiEdge 1600G-LR Datasheet, Rev. A) were retained as part of the teardown documentation. Photographs of the sealed packaging and all exterior labeling were taken upon receipt at Benchmark's facility, prior to any handling or disassembly. These materials are cataloged in the Benchmark teardown report at Appendix A (Chain of Custody Log) and Appendix B (Product Documentation Archive).

B. Chain of Custody Protocol

Kevin Ng, Benchmark's Lead Engineer for this engagement, maintained comprehensive chain of custody documentation from the date of receipt through the completion of all teardown activities. The chain of custody log records every instance of access to the sample units, including the date, time, identity of the individual accessing the sample, and the nature of the activity performed. This documentation is consistent with Benchmark's standard operating procedures for litigation-support teardowns, which have been accepted by courts in prior proceedings. See, e.g., MicroTech Innovations, Inc. v. Solara Optics, Inc., No. 3:19-cv-01487-RS (N.D. Cal.) (Benchmark teardown admitted over objection).

The sample units were stored in Benchmark's controlled-access lab facility at 2244 Mission College Boulevard, Santa Clara, CA 95054, throughout the engagement. Access to the laboratory is restricted by electronic badge entry, and the specific storage area for litigation samples is further secured by a combination lock with access limited to the lead engineer and the Benchmark engagement manager. Environmental controls (temperature and humidity) were maintained within the specifications recommended for optical transceiver storage (0°C to 40°C, 5% to 85% relative humidity, non-condensing) to prevent degradation of the product prior to testing.

All teardown steps were photographed and documented in accordance with Benchmark's Standard Operating Procedure No. SOP-210-Rev.7 (Litigation Teardown and Documentation Protocol). Each disassembly step was accompanied by high-resolution digital photography using a Nikon D850 DSLR with macro lens, and SEM imaging was performed using a JEOL JSM-7800F field-emission scanning electron microscope. Kevin Ng confirmed this methodology and its consistency with the prior two teardowns in his deposition on January 7, 2025. See Deposition of Kevin Ng, Jan. 7, 2025, at 47:3–49:18 (confirming methodology), 52:11–53:8 (confirming chain of custody for all LumiEdge 1600G-LR samples). A separate Deposition Summary for Kevin Ng's testimony is maintained in the case file (internal digest dated January 10, 2025).

The intact and disassembled samples are preserved at Benchmark's facility for potential trial demonstrative use and for inspection by defense experts during expert discovery. Unit TD-01 was the primary teardown unit and was subjected to full destructive analysis, including die decapsulation and cross-sectional cutting. Units TD-02 and TD-03 remain intact as reference samples and are available for nondestructive inspection. Unit TD-04 has been partially disassembled (module-level only, no die-level analysis) and is available as an intermediate reference.

C. Teardown Methodology

The Benchmark teardown of the LumiEdge 1600G-LR was conducted using a multi-phase methodology designed to capture both module-level and die-level architectural and compositional details. The methodology is consistent with that used for the prior two teardowns in this matter (LumiLink 400G-ZR+ and LumiLink 800G-DR8), ensuring comparability of results across the three accused products. The following phases were employed:

Phase 1: Non-Destructive External Inspection. The external inspection phase included visual examination and documentation of the module housing, form factor, connector interfaces, labeling, and surface-mount markings. Dimensional measurements were taken using calibrated digital calipers (Mitutoyo 500-196-30 Absolute Digimatic Caliper, calibration certificate dated October 15, 2023). The connector interface was characterized by type, pin count, and mechanical alignment features. The module form factor was confirmed to be OSFP (Octal Small Form Factor Pluggable), consistent with Lumicore's product datasheet specifications and industry-standard MSA (Multi-Source Agreement) specifications for 1.6T modules.

Phase 2: Module-Level Disassembly. Following external inspection, the module housing was opened using non-destructive mechanical separation techniques (precision screwdriver removal of fasteners, controlled prying of housing clips). The internal printed circuit board ("PCB") was extracted, and the optical subassembly was separated from the electronic subassembly. The thermal management solution (heat sink and thermal interface material) was removed and documented, including thermal interface material thickness measurements and heat-sink fin geometry characterization. While the thermal management structures were documented for completeness, they are not directly relevant to the asserted claim limitations for the LumiEdge 1600G-LR, as the '562 Patent thermal-management claims are not asserted against this product.

Phase 3: Die-Level Analysis. The die-level analysis phase involved the following sub-procedures:

• PIC Die Decapsulation: The photonic integrated circuit die was removed from the optical subassembly using precision mechanical and chemical decapsulation techniques. The decapsulation process was performed by Kevin Ng and documented with step-by-step photography.

• Scanning Electron microscopy (SEM): SEM imaging was performed at multiple magnifications (100x, 500x, 1,000x, 5,000x, 10,000x, 25,000x, and 50,000x) on key structures of interest, including the grating coupler region, the coherent transceiver engine region, the waveguide routing structures, and the photodetector arrays. The SEM images are cataloged in the Benchmark report at Section 5 (SEM Image Archive) and are cross-referenced to specific claim limitations in the claim charts attached to this memorandum as part of the summary tables in Sections IV.G and V.F.

• Cross-Sectional Analysis: Focused ion beam (FIB) milling was used to prepare cross-sections of the PIC die at critical regions, including: (a) the grating coupler interface, to characterize etch depth, grating period, fill factor, and layer stack composition; (b) the silicon substrate and fabrication layers, to determine the integration methodology (monolithic vs. hybrid bonding vs. heterogeneous integration); and (c) the coherent detection module region, to characterize the optical hybrid and photodetector structures. Cross-sectional SEM images are provided in the Benchmark report at Section 6 (Cross-Sectional Analysis).

• Optical microscopy: Brightfield and darkfield optical microscopy was employed for initial die-level inspection and to document large-scale features and routing.

• Energy-Dispersive X-ray Spectroscopy (EDS): EDS was performed in conjunction with SEM imaging to characterize the material composition of key structures, including the grating coupler features, the waveguide core and cladding materials, and the bonding interfaces (if any) between different material layers. EDS results confirmed that the PIC die is fabricated on a silicon substrate with silicon dioxide cladding and silicon nitride waveguide layers, among other materials identified and documented in the Benchmark report.

Phase 4: Functional Testing. The functional testing phase was conducted on Unit TD-02 (an intact reference sample) to characterize the optical performance of the LumiEdge 1600G-LR without compromising the unit subjected to destructive die-level analysis. Functional tests included:

• Insertion loss measurement at operating wavelength (C-band, 1530–1565 nm)

• Return loss measurement

• Polarization-dependent loss (PDL) measurement

• Spectral response characterization

• Coherent detection performance measurement (constellation quality, error vector magnitude, signal-to-noise ratio)

• Grating coupler efficiency estimation (derived from insertion loss measurements and comparison to reference coupler designs)

The functional test data are reported in the Benchmark report at Section 7 (Functional Performance Characterization) and are relevant to both the literal infringement analysis (confirming that the accused product achieves the claimed functional parameters) and the doctrine of equivalents analysis (demonstrating that the accused design achieves substantially the same result as the claimed structures).

III. PRODUCT OVERVIEW — LUMICORE LumiEdge 1600G-LR

A. Product Description

The LumiEdge 1600G-LR is a 1600G (1.6 Tbps aggregate) long-reach coherent optical transceiver module designed for hyperscale data-center interconnect ("DCI") and telecom metro/long-haul applications. It represents Lumicore's highest-bandwidth product in its accused product line and is the most recently launched accused product in this litigation. The module is designed to provide high-capacity, low-latency optical connectivity over distances up to 80 kilometers, utilizing dual-polarization 16-QAM modulation on each of multiple wavelength channels carried on a single fiber pair.

The LumiEdge 1600G-LR is housed in an OSFP (Octal Small Form Factor Pluggable) form factor, consistent with the industry-standard OSFP Multi-Source Agreement for next-generation high-bandwidth transceiver modules. The module utilizes LC duplex optical connectors for the line-side optical interface and a high-density electrical connector (compliant with the OSFP MSA electrical interface specification) for the host-side electrical interface. The module operates at a nominal power consumption of 28W, as specified in Lumicore's product datasheet (LumiEdge 1600G-LR Datasheet, Rev. A, dated September 2023).

The LumiEdge 1600G-LR is designed to compete directly with OWS's OWS-1600DR transceiver module family, which was launched in Q2 2023 and represents OWS's current flagship coherent transceiver product. Both products target the same customer base (hyperscale cloud service providers and tier-1 telecom operators), serve the same applications (DCI and metro/long-haul), and offer comparable performance specifications. The competitive overlap between the LumiEdge 1600G-LR and the OWS-1600DR is significant to the lost-profits damages analysis, as discussed in Section VIII.A below.

B. Market Context

The LumiEdge 1600G-LR was commercially launched by Lumicore in Q4 2023, with first customer shipments occurring in October 2023 according to Lumicore's earnings call transcript for the quarter ended December 31, 2023. The product generated estimated FY 2023 revenue of $41.7 million, representing a partial-year figure (approximately one quarter of revenue) given the Q4 2023 launch timing. Lumicore's management characterized the LumiEdge 1600G-LR as a "transformational product" during the Q4 2023 earnings call and indicated strong customer demand driven by accelerating hyperscale data-center buildouts and the transition to 1.6T-and-beyond optical networking infrastructure.

Total projected accused-product revenue across all three accused products — the LumiLink 400G-ZR+, the LumiLink 800G-DR8, and the LumiEdge 1600G-LR — through Q4 2025 is approximately $714.6 million per Dr. Lawrence Keating's (Meridian Economic Consulting Group, LLC) preliminary damages analysis. Of this total, the LumiEdge 1600G-LR is projected to contribute an increasing proportion of revenue as the 400G-ZR+ product reaches end-of-life and the 800G-DR8 transitions to a legacy platform. Dr. Keating's analysis projects LumiEdge 1600G-LR revenue of approximately $195 million in FY 2024 and $260 million in FY 2025, representing an anticipated compound annual growth rate consistent with broader industry forecasts for 1.6T coherent transceiver adoption.

This product is accused of infringing the '193 Patent and the '015 Patent. Notably, the '847 Patent and the '562 Patent are not asserted against the LumiEdge 1600G-LR. Those patents are asserted only against the LumiLink 400G-ZR+ and LumiLink 800G-DR8 products, based on specific thermal management and wavelength-division multiplexing features present in those earlier-generation products that are addressed differently in the LumiEdge 1600G-LR architecture.

C. Key Technical Architecture (Per Teardown)

The Benchmark teardown reveals the following key architectural features of the LumiEdge 1600G-LR, each of which is relevant to the infringement analysis for one or both of the asserted patents:

Silicon Photonic Integrated Circuit (PIC) Die. The core of the LumiEdge 1600G-LR is a silicon photonic integrated circuit die that contains the coherent transceiver optical engine. The PIC die measures approximately 17.2 mm × 12.8 mm and is fabricated using a multi-layer silicon photonic process. The die incorporates optical modulators (Mach-Zehnder modulators for coherent modulation), waveguide routing structures, grating couplers for fiber-to-chip optical coupling, coherent detection optics (including optical hybrids and balanced photodetectors), and polarization handling elements. The PIC die is the primary structural element relevant to both the '193 Patent and the '015 Patent claim limitations.

Grating Coupler Structures. The PIC die incorporates grating coupler structures at the fiber-to-chip optical interface. These grating couplers are the primary structures relevant to the '015 Patent infringement analysis. The teardown reveals a periodic grating pattern etched into the silicon waveguide layer, with specific geometric parameters (grating period, etch depth, fill factor, and polarization-handling geometry) that correspond to the claimed polarization-diverse grating coupler. The grating coupler design is discussed in detail in Section V below.

Coherent Detection Architecture. The LumiEdge 1600G-LR PIC die incorporates a coherent detection architecture that includes polarization beam splitting, 90-degree optical hybrids, and balanced photodetector arrays. This architecture enables the recovery of amplitude and phase information from coherent optical signals and is central to the '193 Patent infringement analysis. The coherent detection module design, including the specific structural variants identified in the teardown, is discussed in detail in Section IV below.

Electronic IC (EIC). The module incorporates a separate electronic integrated circuit die (EIC) that performs digital signal processing ("DSP") functions, including forward error correction, equalization, and modulation/demodulation. The EIC is manufactured by a third-party semiconductor foundry (believed to be Drayton Holdings, based on die markings and process node characteristics observed in the teardown) and is connected to the PIC die through a high-density electrical interconnect. The EIC is not directly implicated by the asserted patent claims, which are directed to the photonic structures rather than the electronic signal processing.

Thermal Management Structures. The module incorporates thermal management structures including a copper heat spreader, thermal interface materials (phase-change thermal pads), and a heat-sink assembly integrated into the OSFP housing lid. While these structures were documented by Benchmark for completeness, they are not directly relevant to the asserted claims for the LumiEdge 1600G-LR. The '562 Patent, which contains thermal-management claims, is not asserted against this product.

IV. CLAIM-LIMITATION CROSS-REFERENCE ANALYSIS — '193 PATENT (U.S. Patent No. 10,891,193)

A. Patent Overview

The '193 Patent, titled "High-Bandwidth Coherent Optical Transceiver Integrated on Silicon Substrate," was filed on April 7, 2017, claiming priority to Provisional Application No. 62/499,117, also filed on April 7, 2017. The patent issued on January 12, 2021. The original and current assignee is Optiwave Semiconductor Corp. The named inventors include Dr. Jian-Wei Huang, who serves as OWS's Chief Technology Officer and is expected to be a fact witness at trial regarding the conception and development of the patented technology.

The '193 Patent is generally directed to a coherent optical transceiver architecture that is integrated on a silicon substrate using semiconductor fabrication processes. The patent describes a silicon photonic platform that enables high-bandwidth coherent optical communication by integrating optical modulators, coherent detection optics, waveguides, and polarization-handling elements on a single silicon-based chip. The claimed invention addresses the longstanding challenge in the field of achieving high-performance coherent transceiver functionality within the constraints of silicon photonic fabrication, which historically has been limited in its ability to support the complex optical functions required for coherent detection.

The following claims of the '193 Patent are asserted against the LumiEdge 1600G-LR: Claims 1, 3, 7, 10, 15, and 18. Claims 1 and 10 are independent claims. Claims 3 and 7 depend from Claim 1. Claim 15 depends from Claim 10. Claim 18 depends from Claim 15.

B. Claim 1 — Literal Infringement Mapping

Independent Claim 1 of the '193 Patent recites a coherent optical transceiver module integrated on a silicon substrate, comprising a plurality of specified structural elements. The following analysis maps each limitation of Claim 1 to the corresponding structures and components identified in the Benchmark teardown of the LumiEdge 1600G-LR.

Preamble: "A coherent optical transceiver module." The LumiEdge 1600G-LR is a coherent optical transceiver module. Benchmark's functional testing confirms that the module performs coherent modulation and detection of optical signals, employing dual-polarization quadrature amplitude modulation (DP-16QAM) to encode and decode data onto optical carrier signals. The product datasheet, marketing materials, and functional test results all confirm that the LumiEdge 1600G-LR is a coherent optical transceiver module within any reasonable construction of this preamble term. Even if the preamble is construed as a limitation (which OWS does not concede), this element is plainly met.

Limitation 1(a): "a silicon substrate." The Benchmark teardown, through cross-sectional SEM analysis and EDS material composition testing, confirms that the PIC die at the core of the LumiEdge 1600G-LR is fabricated on a silicon substrate. EDS spectra obtained at the substrate layer confirm silicon as the primary elemental composition, with a silicon dioxide buried oxide ("box") layer and silicon device layers consistent with a silicon-on-insulator ("SOI") fabrication platform. The silicon substrate has a thickness of approximately 725 μm, consistent with standard 200 mm or 300 mm SOI wafer thicknesses used in commercial silicon photonic foundry processes. See Benchmark Report, Section 6.2, Figures 6-4 through 6-8 (cross-sectional SEM images of substrate and layer stack).

This limitation implicates the disputed claim construction term "integrated on a silicon substrate." OWS proposes the construction "formed on or within a silicon-based wafer using semiconductor fabrication processes," while Lumicore proposes the narrower construction "monolithically fabricated on a single silicon die without hybrid bonding or heterogeneous integration." The Benchmark cross-sectional analysis is central to resolving this factual question. Specifically, the cross-sectional SEM images at the boundary between the silicon waveguide layer and the germanium photodetector layer reveal an interface that could be interpreted as either a heterogeneously integrated layer or a monolithically grown epitaxial germanium layer. The distinction is significant: if the germanium photodetectors are epitaxially grown on the silicon substrate (as in standard Drayton Holdings or IMEC silicon photonic processes), the structure would satisfy even Lumicore's narrow construction. If, however, the germanium photodetector layer is bonded to the silicon substrate through a wafer-bonding process, Lumicore may argue that its narrow construction is not satisfied. Benchmark's analysis, based on the interface morphology and EDS composition profile at the boundary, indicates that the germanium layer is most likely epitaxially grown, as the interface shows a gradual compositional transition rather than the abrupt interface and bonding oxide characteristic of wafer bonding. This finding supports literal infringement under either proposed construction. However, this issue should be confirmed through analysis of Lumicore's fabrication process documentation when produced in discovery.

Limitation 1(b): "an optical modulator array formed on the silicon substrate, the optical modulator array comprising a plurality of Mach-Zehnder modulators configured to modulate an optical carrier signal." The Benchmark teardown identifies an array of Mach-Zehnder interferometer ("MZI") modulator structures on the PIC die, located in the transmitter region of the coherent transceiver engine. Optical microscopy at 100x magnification reveals a regular array of MZI structures, each comprising input and output waveguide branches, phase-shifting elements, and waveguide combiners. The number of MZI modulators identified is consistent with the dual-polarization IQ modulation architecture required for DP-16QAM coherent modulation: two MZI modulators per quadrature (I and Q) per polarization (TE and TM), yielding eight MZI modulators in total. SEM imaging at higher magnifications (1,000x and 5,000x) reveals the specific geometry of the phase-shifting elements, which appear to be carrier-depletion type PN junction modulators implemented within the silicon rib waveguide structure. See Benchmark Report, Section 5.3, Figures 5-12 through 5-18 (MZI modulator array images).

Limitation 1(c): "a waveguide network formed on the silicon substrate, the waveguide network optically coupling the optical modulator array to at least one fiber coupling interface." The PIC die contains an extensive network of silicon waveguides routing optical signals between the various functional blocks, including from the modulator array to the grating coupler interfaces (which serve as the fiber coupling interface). The waveguide network is visible in die-level optical microscopy images and is further characterized through SEM imaging. Waveguide dimensions measured from SEM cross-sections are approximately 450 nm width × 220 nm height, consistent with standard single-mode silicon strip waveguides in commercial silicon photonic processes. See Benchmark Report, Section 5.4, Figures 5-19 through 5-24 (waveguide routing images and dimensional measurements).

Limitation 1(d): "a coherent detection module formed on the silicon substrate, the coherent detection module comprising at least one optical hybrid and a plurality of balanced photodetectors, the coherent detection module configured to recover amplitude and phase information from received optical signals." The receiver region of the PIC die contains a coherent detection module comprising optical hybrid structures and balanced photodetector pairs. The 90-degree optical hybrid structures are identified through SEM imaging as multi-mode interference ("MMI") couplers configured as 2×4 or 4×4 MMI hybrids. The balanced photodetectors are germanium-on-silicon photodiodes arranged in matched pairs. Functional testing confirms that the coherent detection module recovers both amplitude and phase information from received optical signals, as evidenced by the constellation diagrams and error vector magnitude measurements obtained during performance characterization. See Benchmark Report, Section 5.5, Figures 5-25 through 5-33 (coherent detection module images), and Section 7.3, Tables 7-4 through 7-6 (coherent detection performance data).

This limitation is central to the DOE analysis for dependent Claims 3 and 7, as discussed in Section IV.C below.

Limitation 1(e): "a polarization handling element formed on the silicon substrate, the polarization handling element configured to separate received optical signals into at least two orthogonal polarization components." The PIC die incorporates a polarization handling element in the receiver optical path, upstream of the coherent detection module. SEM imaging reveals a polarization beam splitter/rotator ("PSR") structure implemented using a waveguide taper and mode-coupling geometry. The PSR separates incoming optical signals into TE and TM polarization components and rotates the TM component to TE polarization for processing by the coherent detection module. See Benchmark Report, Section 5.6, Figures 5-34 through 5-38 (polarization handling element images).

Based on the foregoing analysis, each limitation of independent Claim 1 of the '193 Patent is met by corresponding structures identified in the LumiEdge 1600G-LR teardown. The literal infringement case for Claim 1 is strong under OWS's proposed claim constructions and remains viable even under Lumicore's narrower proposed constructions, subject to confirmation of the integration methodology through discovery of fabrication process documentation.

C. Claims 3 and 7 — Literal Infringement and Doctrine of Equivalents

Claims 3 and 7 are dependent claims that depend from Claim 1, incorporating all limitations of Claim 1 and adding further limitations directed to the "coherent detection module."

Claim 3 adds the limitation: "wherein the coherent detection module comprises a polarization-diverse coherent receiver with separate I/Q detection paths for each polarization component." The LumiEdge 1600G-LR's coherent detection module, as identified in the teardown, provides separate I (in-phase) and Q (quadrature) detection paths for each of the two orthogonal polarization components (TE-X and TE-Y, following polarization rotation). The teardown identifies four sets of balanced photodetector pairs corresponding to I-X, Q-X, I-Y, and Q-Y channels, confirming the presence of separate I/Q detection paths for each polarization component. This limitation appears to be literally satisfied.

Claim 7 adds the limitation: "wherein the at least one optical hybrid comprises a 90-degree optical hybrid implemented as a multi-mode interference coupler with at least four output ports." The teardown identifies the optical hybrid structures as MMI couplers. However, Benchmark's analysis reveals a design variant in the LumiEdge 1600G-LR's optical hybrid implementation that warrants careful analysis. Specifically, the LumiEdge 1600G-LR appears to use a cascaded 2×2 MMI coupler arrangement rather than a single 2×4 or 4×4 MMI coupler to achieve the 90-degree hybrid function. The cascaded arrangement produces four output ports in aggregate, but the individual MMI couplers each have only two output ports. Whether this cascaded architecture literally satisfies the claim limitation "a multi-mode interference coupler with at least four output ports" depends on the construction of this phrase — specifically, whether "a multi-mode interference coupler" refers to a single physical MMI coupler or to a functional unit that may comprise multiple cascaded MMI couplers.

Literal Infringement Analysis. Under OWS's proposed interpretation — that "a multi-mode interference coupler with at least four output ports" encompasses any MMI-coupler-based structure that provides at least four output ports, including cascaded configurations — the LumiEdge 1600G-LR literally satisfies this limitation. Under Lumicore's anticipated interpretation — that the claim requires a single, unitary MMI coupler with at least four output ports — literal infringement of Claim 7 may not be established. This issue has been flagged for the claim construction briefing and is addressed in the Markman Hearing Preparation Memorandum (internal, target February 28, 2025).

Doctrine of Equivalents Analysis. In the event that the Court adopts Lumicore's narrower interpretation and literal infringement of Claim 7 is not established, OWS asserts infringement under the doctrine of equivalents. The accused cascaded MMI coupler structure in the LumiEdge 1600G-LR:

• Performs substantially the same function: The cascaded 2×2 MMI coupler arrangement performs the function of a 90-degree optical hybrid — it mixes the received signal with a local oscillator reference to produce four output signals having 0°, 90°, 180°, and 270° relative phase offsets, enabling coherent I/Q detection.

• In substantially the same way: The cascaded arrangement uses multi-mode interference within MMI coupler waveguide structures to achieve the required phase relationships between output ports. The physical mechanism of operation (self-imaging in multi-mode waveguides) is identical to that of a single 4-output MMI coupler. The cascading merely distributes the splitting and phase-shifting functions across two stages rather than one.

• To achieve substantially the same result: The cascaded structure produces four output signals with the required 90-degree phase offsets, enabling recovery of the I and Q components of the coherent optical signal with the same fidelity as a single 4-output MMI hybrid. Benchmark's functional testing confirms that the coherent detection performance of the LumiEdge 1600G-LR (error vector magnitude, constellation quality) is comparable to or exceeds that of reference coherent receivers using single 4-output MMI hybrids.

Prosecution History Estoppel. The application of the doctrine of equivalents to Claim 7 must be analyzed in light of the prosecution history of the '193 Patent. During prosecution, Claim 7 was narrowed in response to a § 102 anticipation rejection over Takahashi et al. ("Dense WDM Silicon Photonic MUX," IEEE Photonics Technology Letters, March 2014). Specifically, the phrase "at least four output ports" was added by amendment to overcome the Takahashi reference, which disclosed a 2×2 MMI coupler with only two output ports. The narrowing amendment raises the question of whether prosecution history estoppel under Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002), bars application of the doctrine of equivalents to encompass the cascaded 2×2 MMI structure in the LumiEdge 1600G-LR.

The Prosecution History Estoppel Analysis — '193 Patent (internal memo dated October 10, 2024) concludes that the Festo presumption is likely rebutted under the "unforeseeability" exception. At the time of the narrowing amendment (January 2019), the cascaded 2×2 MMI coupler arrangement used in the LumiEdge 1600G-LR was not a foreseeable design-around that the applicant could have reasonably been expected to capture through claim language. The cascaded approach, while known in the literature for other applications, had not been demonstrated in a silicon photonic coherent transceiver context at the time of the amendment. Additionally, the amendment was made to distinguish the two-output-port device of Takahashi, and the rationale for the amendment (distinguishing a two-output device from a four-output device) does not bear a tangential or peripheral relationship to the equivalent at issue (a cascaded arrangement that also provides four outputs). This analysis should be further developed in the context of Dr. Ashford's expert report.

Cross-reference is also made to the Doctrine of Equivalents Analysis Memorandum (internal, September 5, 2024), which provides additional discussion of the function-way-result test and the Vitronics / Johnson & Johnston all-limitations rule considerations.

D. Claim 10 — Literal Infringement Mapping

Independent Claim 10 of the '193 Patent is directed to a method of coherent optical communication using a transceiver integrated on a silicon substrate. The following analysis maps each limitation of Claim 10 to the structures and operational characteristics identified in the Benchmark teardown.

Preamble: "A method of coherent optical communication, comprising." The LumiEdge 1600G-LR performs coherent optical communication as its core function. Functional testing by Benchmark confirms the execution of coherent modulation and detection processes.

Limitation 10(a): "providing a coherent optical transceiver module integrated on a silicon substrate, the module comprising an optical modulator array, a waveguide network, and a coherent detection module." This limitation is a "providing" step that recites the same structural elements addressed in the Claim 1 analysis above. As established in Section IV.B, the LumiEdge 1600G-LR incorporates all of these structural elements on its silicon PIC die. The same teardown findings and evidence cited in the Claim 1 analysis apply here.

Limitation 10(b): "modulating, by the optical modulator array, at least one optical carrier signal to encode data onto the optical carrier signal using Ridgeline & Co. modulation." Benchmark's functional testing confirms that the LumiEdge 1600G-LR modulates optical carrier signals using DP-16QAM coherent modulation. The modulation is performed by the MZI modulator array identified on the PIC die. The modulation format and data encoding are confirmed through electrical-domain analysis of the modulated signal and through optical-domain constellation analysis. See Benchmark Report, Section 7.2, Figures 7-3 through 7-5 (transmitter modulation characterization).

Limitation 10(c): "coupling, via a fiber coupling interface, the modulated optical carrier signal to an optical fiber." The modulated optical signals are coupled from the PIC die to the external optical fiber through the grating coupler structures that serve as the fiber coupling interface. Benchmark confirmed the optical coupling through insertion loss measurements and by verifying that modulated optical power was present at the module's LC connector output. See Benchmark Report, Section 7.1, Table 7-1 (insertion loss measurements).

Limitation 10(d): "receiving, via the fiber coupling interface, an incoming modulated optical signal from an optical fiber." The same fiber coupling interface (or a separate grating coupler dedicated to the receiver path, depending on the architecture) receives incoming optical signals. The teardown confirms the presence of dedicated receiver-path grating couplers on the PIC die, and functional testing confirms reception of incoming signal optical signals. See Benchmark Report, Section 5.2, Figure 5-10 (receiver-path grating coupler identification).

Limitation 10(e): "recovering, by the coherent detection module, amplitude and phase information from the incoming modulated optical signal." As established in the Claim 1 analysis (Limitation 1(d)), the coherent detection module on the PIC die recovers amplitude and phase information from received optical signals. This is confirmed by functional testing demonstrating successful coherent demodulation with constellation diagrams showing recovery of 16-QAM symbols. See Benchmark Report, Section 7.3, Figures 7-6 through 7-9 (receiver coherent detection performance).

Based on the foregoing analysis, each limitation of independent Claim 10 is met by the corresponding structures and operations identified in the LumiEdge 1600G-LR teardown. The literal infringement case for Claim 10 is strong.

E. Claim 15 — Literal Infringement Mapping (Means-Plus-Function Considerations)

Claim 15 depends from Claim 10 and adds the limitation: "wherein coupling the modulated optical carrier signal to the optical fiber comprises coupling by means for fiber-to-chip optical coupling integrated on the silicon substrate."

The Means-Plus-Function Analysis Memorandum (internal, dated October 5, 2024) identifies the phrase "means for fiber-to-chip optical coupling" as a potentially means-plus-function term under 35 U.S.C. § 112(f). The use of the word "means" coupled with a functional description ("fiber-to-chip optical coupling") and the absence of sufficient structural recitation in the claim language itself triggers the presumption that § 112(f) applies. OWS does not contest the application of § 112(f) to this term.

Under § 112(f), the "means for fiber-to-chip optical coupling" is construed to cover the corresponding structure disclosed in the '193 Patent specification, and equivalents thereof. The '193 Patent specification discloses two corresponding structures for the "means for fiber-to-chip optical coupling":

1. A grating coupler, described at col. 7, ll. 14–35 and illustrated in Figures 4A–4C of the '193 Patent.

2. An edge coupler (also referred to as a "butt coupler" or "spot-size converter"), described at col. 7, ll. 36–48 and illustrated in Figure 4D of the '193 Patent.

The Benchmark teardown identifies grating coupler structures at the fiber-to-chip interface of the LumiEdge 1600G-LR PIC die. As discussed in Section V (regarding the '015 Patent claims), the grating coupler is characterized in detail through SEM imaging, cross-sectional analysis, and functional testing. The grating coupler structure identified in the LumiEdge 1600G-LR falls within the scope of the corresponding structure disclosed in the '193 Patent specification (i.e., a grating coupler). Accordingly, this limitation is satisfied.

Even if the specific grating coupler design in the LumiEdge 1600G-LR differs in certain design parameters (e.g., grating period, etch depth, fill factor) from the specific grating coupler embodiment illustrated in the '193 Patent Figures 4A–4C, the § 112(f) analysis requires only that the accused structure be the same structure disclosed in the specification or an equivalent structure. A grating coupler is a grating coupler — variations in design parameters do not change the fundamental structural identity. See Odetics, Inc. v. Storage Tech. Corp., 185 F.3d 1259, 1267 (Fed. Cir. 1999) (equivalents under § 112(f) are structural equivalents, not equivalents under the doctrine of equivalents).

F. Claim 18 — Literal Infringement Mapping

Claim 18 depends from Claim 15 (which depends from Claim 10) and adds the limitation: "wherein the coherent optical transceiver module further comprises a polarization beam splitter integrated on the silicon substrate and configured to separate received optical signals into orthogonal polarization components prior to detection by the coherent detection module."

The Benchmark teardown identifies a polarization beam splitter/rotator ("PSR") structure on the PIC die, as discussed in the Claim 1 Limitation 1(e) analysis above. The PSR is integrated on the silicon substrate and is located in the receiver optical path upstream of the coherent detection module, consistent with the claim language specifying that the polarization separation occurs "prior to detection by the coherent detection module." SEM images of the PSR structure show a waveguide taper geometry that separates TE and TM polarization modes using mode-evolution coupling. See Benchmark Report, Section 5.6, Figures 5-34 through 5-38.

The PSR identified in the teardown is a "polarization beam splitter" as recited in the claim. Although the claim does not also recite a polarization rotator, the fact that the LumiEdge 1600G-LR's PSR also rotates the TM component to TE polarization after splitting does not defeat infringement — the PSR performs the claimed function (splitting into orthogonal polarization components) and additionally performs rotation, which is an additional function not excluded by the claim language. Under the well-established principle that the presence of additional, unclaimed features does not negate infringement, the PSR in the LumiEdge 1600G-LR satisfies this limitation. See Pemberton Partners LLC v. F. Hoffmann-La Roche Ltd., 580 F.3d 1340, 1374 (Fed. Cir. 2009).

G. Summary Table — '193 Patent Claims vs. LumiEdge 1600G-LR

The following table summarizes the claim-limitation cross-reference analysis for all asserted claims of the '193 Patent against the LumiEdge 1600G-LR:

V. CLAIM-LIMITATION CROSS-REFERENCE ANALYSIS — '015 PATENT (U.S. Patent No. 11,402,015)

A. Patent Overview

The '015 Patent, titled "Polarization-Diverse Grating Coupler for Silicon Photonic Transceivers," was filed on August 30, 2019, claiming priority to Provisional Application No. 62/499,117, filed April 7, 2017. The '015 Patent thus shares the same provisional priority date as the '193 Patent. The patent issued on August 2, 2022. The original and current assignee is Optiwave Semiconductor Corp. The named inventors include Dr. Jian-Wei Huang and Dr. Mei-Ling Cho, both of OWS's photonics research group.

The '015 Patent is directed to a polarization-diverse grating coupler structure for silicon photonic transceivers that enables efficient coupling of light from an optical fiber to a silicon photonic chip while handling both orthogonal polarization states (TE and TM). The claimed grating coupler design addresses the well-known polarization sensitivity problem in conventional one-dimensional grating couplers, which typically couple only a single polarization state efficiently. The '015 Patent discloses a two-dimensional grating coupler geometry that simultaneously captures both polarization states and routes them to separate waveguide outputs, enabling polarization-diverse operation essential for coherent optical transceivers.

The following claims of the '015 Patent are asserted against the LumiEdge 1600G-LR: Claims 1, 5, 8, 12, and 16. Claim 1 is an independent claim. Claims 5 and 8 depend from Claim 1. Claim 12 depends from Claim 8. Claim 16 depends from Claim 1.

B. Claim 1 — Literal Infringement Mapping

Independent Claim 1 of the '015 Patent recites a polarization-diverse grating coupler for a silicon photonic transceiver, comprising specified structural elements. The following analysis maps each limitation to the structures identified in the Benchmark teardown.

Preamble: "A polarization-diverse grating coupler for a silicon photonic transceiver, comprising." The LumiEdge 1600G-LR incorporates grating coupler structures on its silicon PIC die that serve as the fiber-to-chip optical coupling interface for the coherent transceiver. As discussed below, the grating coupler identified in the teardown is a polarization-diverse design, consistent with the preamble.

Limitation 1(a): "a grating region formed in a waveguide layer on a silicon substrate, the grating region comprising a periodic pattern of features configured to diffract light from an optical fiber into the waveguide layer." The Benchmark teardown identifies a grating region on the PIC die at the fiber-to-chip interface. SEM imaging at 5,000x and 10,000x magnification reveals a periodic pattern of etched features in the silicon waveguide layer. The grating region is positioned beneath the fiber attachment point and is configured to diffract light from the optical fiber (incident at an angle of approximately 8–12 degrees from vertical, based on the fiber attachment geometry observed in the teardown) into the in-plane silicon waveguide layer. The grating is formed in the same waveguide layer (220 nm silicon device layer) that constitutes the silicon photonic waveguide structures throughout the PIC die, and this waveguide layer is formed on the silicon substrate (SOI platform). See Benchmark Report, Section 5.2, Figures 5-7 through 5-11 (grating region overview images), and Section 6.3, Figures 6-9 through 6-14 (cross-sectional analysis of grating features).

The grating period, as measured from SEM images, is approximately 610 nm ± 5 nm. The etch depth is approximately 70 nm (partial etch of the 220 nm silicon device layer). The fill factor (ratio of etched to unetched regions) is approximately 0.50. These parameters are consistent with a grating coupler optimized for C-band (1550 nm center wavelength) operation on a standard SOI platform.

Limitation 1(b): "wherein the periodic pattern of features is arranged in a two-dimensional array such that the grating region is configured to couple light of a first polarization state into a first waveguide output and light of a second polarization state, orthogonal to the first polarization state, into a second waveguide output." This limitation contains the disputed claim construction term "polarization-diverse grating coupler," and the specific structural requirement of a "two-dimensional array" of features.

The Benchmark SEM imagery reveals that the grating coupler in the LumiEdge 1600G-LR uses a two-dimensional pattern of features — specifically, a grid-like arrangement of rectangular or square features (holes or posts) arranged in both the x and y directions, rather than a one-dimensional array of parallel lines. This two-dimensional geometry is characteristic of a polarization-diverse grating coupler design that simultaneously captures both TE and TM polarization components of the incoming fiber light and routes them to two separate waveguide outputs oriented at approximately 90 degrees to each other.

SEM images at 25,000x magnification clearly show the two-dimensional periodicity of the grating features. The grating periods in the two orthogonal directions are measured to be approximately 610 nm (x-direction) and 615 nm (y-direction), with the slight asymmetry likely intentional to optimize polarization splitting performance. Two waveguide outputs are observed emanating from the grating region at approximately 90-degree angles, consistent with the claim requirement that light of one polarization state is coupled into a first waveguide output and light of the orthogonal polarization state is coupled into a second waveguide output. See Benchmark Report, Section 5.2, Figures 5-8 through 5-11 (grating coupler plan-view SEM images), and Section 6.3, Figures 6-9 through 6-14 (cross-sectional analysis).

Analysis Under Competing Claim Constructions. OWS proposes that "polarization-diverse grating coupler" be construed as "a grating coupler capable of coupling light of two orthogonal polarization states." Under this construction, the LumiEdge 1600G-LR's grating coupler plainly satisfies the limitation, as the two-dimensional grating pattern and dual waveguide outputs confirm the ability to couple both orthogonal polarization states.

Lumicore proposes the narrower construction "a two-dimensional grating coupler with a polarization-splitting element that simultaneously couples TE and TM modes." This construction adds two requirements beyond OWS's proposal: (1) the presence of a "polarization-splitting element" as a distinct structural feature, and (2) the requirement of "simultaneous" coupling of TE and TM modes.

With respect to the "polarization-splitting element" requirement, the two-dimensional grating structure itself functions as the polarization-splitting element — the two-dimensional periodicity inherently splits the two polarization states by diffracting them into different waveguide outputs. Whether Lumicore's construction requires a separate, identifiable "polarization-splitting element" distinct from the grating itself is a question of claim construction. If the grating structure itself qualifies as the "polarization-splitting element" (as OWS contends it should), then this requirement is satisfied. If Lumicore's construction requires an additional, separate element, the literal infringement analysis would depend on whether any additional structural feature in the grating coupler region serves this function.

With respect to the "simultaneous" coupling requirement, the two-dimensional grating coupler in the LumiEdge 1600G-LR operates by simultaneously diffracting both polarization components — the TE-polarized light couples into the waveguide output oriented along one axis, and the TM-polarized light (which appears as TE-like polarization along the orthogonal axis due to the 2D grating geometry) couples into the waveguide output oriented along the perpendicular axis. This simultaneous operation is inherent in the physics of a two-dimensional grating coupler and is confirmed by Benchmark's functional testing showing simultaneous coupling of both polarization states. Accordingly, even under Lumicore's narrower construction, the "simultaneous" coupling requirement is satisfied.

Limitation 1(c): "wherein the first waveguide output and the second waveguide output are coupled to a coherent transceiver optical engine." The two waveguide outputs from the grating coupler are traced through the waveguide routing network on the PIC die to the coherent detection module, which is part of the coherent transceiver optical engine. The waveguide routing is visible in die-level optical microscopy images and confirmed through SEM imaging at the routing junctions. See Benchmark Report, Section 5.4, Figures 5-19 through 5-24 (waveguide routing from grating coupler to coherent detection module).

Based on the foregoing analysis, each limitation of independent Claim 1 of the '015 Patent is met by corresponding structures identified in the LumiEdge 1600G-LR teardown. The literal infringement case for Claim 1 is strong under both competing claim constructions.

C. Claims 5 and 8 — Literal Infringement Mapping

Claim 5 depends from Claim 1 and adds the limitation: "wherein the grating region has an etch depth between 50 nm and 100 nm and a fill factor between 0.40 and 0.60." Benchmark's cross-sectional SEM analysis of the grating coupler region measures an etch depth of approximately 70 nm and a fill factor of approximately 0.50. Both values fall within the ranges specified in Claim 5. The etch depth was determined by FIB cross-sectioning at three separate locations across the grating region, yielding consistent measurements of 68 nm, 71 nm, and 72 nm (average: 70.3 nm). The fill factor was determined by measurement of the etched and unetched feature widths from plan-view SEM images at 25,000x magnification across multiple unit cells. See Benchmark Report, Section 6.3, Figures 6-11 through 6-14 (cross-sectional etch depth measurements), and Section 5.2, Table 5-2 (fill factor measurements). This limitation is literally satisfied.

Claim 8 depends from Claim 1 and adds the limitation: "wherein the grating region is configured to provide a coupling efficiency of at least -3 dB for each of the first and second polarization states at a center wavelength within the C-band." Benchmark's functional testing of the grating coupler, derived from insertion loss measurements and component-level loss analysis, estimates a coupling efficiency of approximately -2.4 dB for the TE polarization state and approximately -2.7 dB for the TM polarization state at a center wavelength of 1550 nm. Both values exceed the -3 dB threshold specified in Claim 8. The coupling efficiency measurements were obtained by deconvolving the total fiber-to-fiber insertion loss into its component contributions (grating coupler loss, waveguide propagation loss, modulator insertion loss, etc.) using reference measurements and component-level characterization. See Benchmark Report, Section 7.1, Tables 7-1 through 7-3 (insertion loss breakdown and coupling efficiency estimates). This limitation is literally satisfied.

D. Claim 12 — Literal Infringement and Doctrine of Equivalents

Claim 12 depends from Claim 8 (which depends from Claim 1) and adds the limitation: "wherein the grating region further comprises a two-dimensional sub-wavelength grating overlaid on the periodic pattern of features, the sub-wavelength grating configured to reduce back-reflection and improve polarization extinction ratio."

Literal Infringement Analysis. Benchmark's SEM analysis of the grating coupler region in the LumiEdge 1600G-LR reveals, in addition to the primary grating pattern (with ~610 nm period), a finer-scale secondary pattern of features within the grating region. This secondary pattern has a feature periodicity of approximately 280 nm, which is below the operating wavelength of 1550 nm (and also below the effective wavelength in silicon, λ/n ≈ 1550/3.47 ≈ 447 nm) and thus qualifies as "sub-wavelength" in the context of the operating medium. The secondary pattern is visible in SEM images at 50,000x magnification and appears to be a set of small rectangular features etched within the primary grating unit cells. See Benchmark Report, Section 5.2, Figures 5-9 through 5-11 (high-magnification SEM of sub-wavelength features).

The key question for literal infringement is whether this secondary pattern constitutes a "two-dimensional sub-wavelength grating overlaid on the periodic pattern of features" as clai

ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL Prepared in anticipation of litigation by Calderwood & Harkness LLP. Not to be disclosed outside the attorney-client relationship without prior written authorization.
CALDERWOOD & HARKNESS LLP Attorneys at Law
March 8, 2024
Benchmark Teardown Report Summary — LumiEdge 1600G-LR
INTERNAL ATTORNEY WORK PRODUCT — PRIVILEGED AND CONFIDENTIAL
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I. EXECUTIVE SUMMARY
Purpose. This memorandum summarizes and analyzes the teardown report prepared by Benchmark Semiconductor Analysis, LLC ("Benchmark") for the Lumicore Technologies, Inc. ("Lumicore") LumiEdge 1600G-LR optical transceiver module. The memorandum cross-references the teardown findings to the claim limitations of the two asserted patents relevant to this product: U.S. Patent No. 10,891,193 (the "'193 Patent") and U.S. Patent No. 11,402,015 (the "'015 Patent"). This document is intended to serve as a working reference for the litigation team and to facilitate preparation of expert reports, infringement contentions supplements, and trial demonstratives.
Teardown Lab. The teardown was conducted by Benchmark Semiconductor Analysis, LLC, located at 2244 Mission College Boulevard, Santa Clara, CA 95054. The lead engineer for this teardown was Kevin Ng, who has served as Benchmark's lead engineer for all three teardowns conducted in this matter. Mr. Ng holds a Ph.D. in Electrical Engineering from Stanford University and has over fifteen years of experience in semiconductor failure analysis and reverse engineering.
Date of Teardown Report Delivery. Benchmark delivered its final teardown report for the LumiEdge 1600G-LR in February 2024. This is the third and most recent teardown conducted by Benchmark in this matter. The prior teardowns were as follows:
1. LumiLink 400G-ZR+ — Report delivered December 12, 2022. This was the first teardown commissioned in the matter and supported the original infringement analysis that led to the filing of this action.
2. LumiLink 800G-DR8 — Report delivered June 2023. This teardown was commissioned after Lumicore launched the 800G-DR8 product and Optiwave Semiconductor Corp. ("OWS") identified it as an additional accused product.
3. LumiEdge 1600G-LR — Report delivered February 2024. This teardown is the subject of this memorandum.
Product Examined. The product examined was the LumiEdge 1600G-LR transceiver module, manufactured and sold by Lumicore Technologies, Inc. (headquarters: 9200 Spectrum Boulevard, Building C, Austin, TX 78759). The LumiEdge 1600G-LR was launched in Q4 2023 and represents Lumicore's flagship coherent transceiver offering, targeting hyperscale data-center interconnect and long-haul telecom applications. Per Lumicore's most recent segment disclosures filed with the Securities and Exchange Commission, the LumiEdge 1600G-LR generated estimated FY 2023 revenue of $41.7 million. This figure represents a partial-year revenue amount given the product's Q4 2023 launch, and revenue is expected to grow substantially through the projected trial date.
Key Conclusion. The teardown confirms the presence of structures and functional elements in the LumiEdge 1600G-LR that correspond to the asserted claim limitations of the '193 Patent (Claims 1, 3, 7, 10, 15, 18) and the '015 Patent (Claims 1, 5, 8, 12, 16). Of particular note:
• The product incorporates a polarization-diverse grating coupler structure that is central to the infringement analysis for the '015 Patent. SEM imagery at multiple magnifications reveals a grating geometry consistent with the claimed structures, including features relevant to the disputed "polarization-diverse grating coupler" claim construction term.
• The product incorporates a coherent optical transceiver architecture integrated on a silicon substrate that maps to the '193 Patent claims. Cross-sectional analysis and material composition testing confirm that the transceiver optical engine is formed on a silicon-based wafer using semiconductor fabrication processes, directly implicating the disputed "integrated on a silicon substrate" claim construction term.
• The LumiEdge 1600G-LR's silicon photonic integrated circuit ("PIC") die incorporates both the coherent transceiver engine and the grating coupler structures on the same photonic chip, demonstrating the integration of the patented innovations within a single product.
Doctrine of Equivalents Relevance. This teardown is particularly important for the doctrine of equivalents ("DOE") analysis pertaining to Claims 3 and 7 of the '193 Patent (regarding the "coherent detection module" limitation) and Claim 12 of the '015 Patent (regarding the "two-dimensional sub-wavelength grating" limitation). The LumiEdge 1600G-LR uses design variants that may not literally satisfy certain claim limitations but that perform substantially the same function, in substantially the same way, to achieve substantially the same result. The DOE analysis is discussed in detail in Sections IV.C and V.D below, and cross-references to the applicable prosecution history estoppel analyses are provided therein.
Note on Product Timing. The LumiEdge 1600G-LR was launched after Lumicore received both FairPoint Licensing Group, LLC's first licensing letter (dated January 15, 2023, identifying the '847, '193, and '562 Patents) and second licensing letter (dated May 15, 2023, adding the '015 Patent and expanding the list of accused products). Lumicore formally declined to take a license on July 10, 2023, stating that it had obtained "competent legal opinions" that its products do not infringe. Despite this notice, Lumicore proceeded to launch the LumiEdge 1600G-LR in Q4 2023. Lumicore's decision to launch this product despite actual notice of the asserted patents is relevant to the willful infringement analysis under Halo Electronics, Inc. v. Pulse Electronics, Inc., 579 U.S. 93 (2016), and OWS's request for enhanced damages under 35 U.S.C. § 284. This issue is discussed in further detail in Section VIII.B below.
II. BACKGROUND AND CHAIN OF CUSTODY
A. Product Acquisition
The LumiEdge 1600G-LR sample units examined in the Benchmark teardown were acquired through commercial distribution channels to ensure the authenticity and provenance of the product. Calderwood & Harkness LLP, on behalf of OWS, directed the acquisition of three (3) sealed LumiEdge 1600G-LR transceiver modules in late Q4 2023, shortly following the product's commercial launch. The modules were purchased from Horizon Network Supply, Inc., an authorized Lumicore distributor, on December 18, 2023. A fourth unit was subsequently purchased on January 9, 2024, from a separate authorized distributor, DataPath Components Group, LLC, to provide redundancy and ensure that the initial units were representative of commercially available product.
All four units were shipped directly to Benchmark's controlled-access laboratory in Santa Clara, California. Upon receipt, Benchmark recorded the serial numbers, lot numbers, and date codes for each unit. The specific identifiers for the primary teardown unit (designated "Unit TD-01") are as follows:
• Serial Number: LME-1600LR-2023Q4-0041827
• Lot Number: LT-2023-1109-A3
• Date Code: 2347 (indicating Week 47, 2023 manufacture)
• Purchase Source: Horizon Network Supply, Inc. (Invoice No. HNS-2023-18742)
• Date of Purchase: December 18, 2023
• Date of Receipt at Benchmark: December 22, 2023
Product packaging, labeling, marketing materials, and accompanying technical documentation (including the Lumicore LumiEdge 1600G-LR Product Brief, Rev. 1.2, and the LumiEdge 1600G-LR Datasheet, Rev. A) were retained as part of the teardown documentation. Photographs of the sealed packaging and all exterior labeling were taken upon receipt at Benchmark's facility, prior to any handling or disassembly. These materials are cataloged in the Benchmark teardown report at Appendix A (Chain of Custody Log) and Appendix B (Product Documentation Archive).
B. Chain of Custody Protocol
Kevin Ng, Benchmark's Lead Engineer for this engagement, maintained comprehensive chain of custody documentation from the date of receipt through the completion of all teardown activities. The chain of custody log records every instance of access to the sample units, including the date, time, identity of the individual accessing the sample, and the nature of the activity performed. This documentation is consistent with Benchmark's standard operating procedures for litigation-support teardowns, which have been accepted by courts in prior proceedings. See, e.g., MicroTech Innovations, Inc. v. Solara Optics, Inc., No. 3:19-cv-01487-RS (N.D. Cal.) (Benchmark teardown admitted over objection).
The sample units were stored in Benchmark's controlled-access lab facility at 2244 Mission College Boulevard, Santa Clara, CA 95054, throughout the engagement. Access to the laboratory is restricted by electronic badge entry, and the specific storage area for litigation samples is further secured by a combination lock with access limited to the lead engineer and the Benchmark engagement manager. Environmental controls (temperature and humidity) were maintained within the specifications recommended for optical transceiver storage (0°C to 40°C, 5% to 85% relative humidity, non-condensing) to prevent degradation of the product prior to testing.
All teardown steps were photographed and documented in accordance with Benchmark's Standard Operating Procedure No. SOP-210-Rev.7 (Litigation Teardown and Documentation Protocol). Each disassembly step was accompanied by high-resolution digital photography using a Nikon D850 DSLR with macro lens, and SEM imaging was performed using a JEOL JSM-7800F field-emission scanning electron microscope. Kevin Ng confirmed this methodology and its consistency with the prior two teardowns in his deposition on January 7, 2025. See Deposition of Kevin Ng, Jan. 7, 2025, at 47:3–49:18 (confirming methodology), 52:11–53:8 (confirming chain of custody for all LumiEdge 1600G-LR samples). A separate Deposition Summary for Kevin Ng's testimony is maintained in the case file (internal digest dated January 10, 2025).
The intact and disassembled samples are preserved at Benchmark's facility for potential trial demonstrative use and for inspection by defense experts during expert discovery. Unit TD-01 was the primary teardown unit and was subjected to full destructive analysis, including die decapsulation and cross-sectional cutting. Units TD-02 and TD-03 remain intact as reference samples and are available for nondestructive inspection. Unit TD-04 has been partially disassembled (module-level only, no die-level analysis) and is available as an intermediate reference.
C. Teardown Methodology
The Benchmark teardown of the LumiEdge 1600G-LR was conducted using a multi-phase methodology designed to capture both module-level and die-level architectural and compositional details. The methodology is consistent with that used for the prior two teardowns in this matter (LumiLink 400G-ZR+ and LumiLink 800G-DR8), ensuring comparability of results across the three accused products. The following phases were employed:
Phase 1: Non-Destructive External Inspection. The external inspection phase included visual examination and documentation of the module housing, form factor, connector interfaces, labeling, and surface-mount markings. Dimensional measurements were taken using calibrated digital calipers (Mitutoyo 500-196-30 Absolute Digimatic Caliper, calibration certificate dated October 15, 2023). The connector interface was characterized by type, pin count, and mechanical alignment features. The module form factor was confirmed to be OSFP (Octal Small Form Factor Pluggable), consistent with Lumicore's product datasheet specifications and industry-standard MSA (Multi-Source Agreement) specifications for 1.6T modules.
Phase 2: Module-Level Disassembly. Following external inspection, the module housing was opened using non-destructive mechanical separation techniques (precision screwdriver removal of fasteners, controlled prying of housing clips). The internal printed circuit board ("PCB") was extracted, and the optical subassembly was separated from the electronic subassembly. The thermal management solution (heat sink and thermal interface material) was removed and documented, including thermal interface material thickness measurements and heat-sink fin geometry characterization. While the thermal management structures were documented for completeness, they are not directly relevant to the asserted claim limitations for the LumiEdge 1600G-LR, as the '562 Patent thermal-management claims are not asserted against this product.
Phase 3: Die-Level Analysis. The die-level analysis phase involved the following sub-procedures:
• PIC Die Decapsulation: The photonic integrated circuit die was removed from the optical subassembly using precision mechanical and chemical decapsulation techniques. The decapsulation process was performed by Kevin Ng and documented with step-by-step photography.
• Scanning Electron microscopy (SEM): SEM imaging was performed at multiple magnifications (100x, 500x, 1,000x, 5,000x, 10,000x, 25,000x, and 50,000x) on key structures of interest, including the grating coupler region, the coherent transceiver engine region, the waveguide routing structures, and the photodetector arrays. The SEM images are cataloged in the Benchmark report at Section 5 (SEM Image Archive) and are cross-referenced to specific claim limitations in the claim charts attached to this memorandum as part of the summary tables in Sections IV.G and V.F.
• Cross-Sectional Analysis: Focused ion beam (FIB) milling was used to prepare cross-sections of the PIC die at critical regions, including: (a) the grating coupler interface, to characterize etch depth, grating period, fill factor, and layer stack composition; (b) the silicon substrate and fabrication layers, to determine the integration methodology (monolithic vs. hybrid bonding vs. heterogeneous integration); and (c) the coherent detection module region, to characterize the optical hybrid and photodetector structures. Cross-sectional SEM images are provided in the Benchmark report at Section 6 (Cross-Sectional Analysis).
• Optical microscopy: Brightfield and darkfield optical microscopy was employed for initial die-level inspection and to document large-scale features and routing.
• Energy-Dispersive X-ray Spectroscopy (EDS): EDS was performed in conjunction with SEM imaging to characterize the material composition of key structures, including the grating coupler features, the waveguide core and cladding materials, and the bonding interfaces (if any) between different material layers. EDS results confirmed that the PIC die is fabricated on a silicon substrate with silicon dioxide cladding and silicon nitride waveguide layers, among other materials identified and documented in the Benchmark report.
Phase 4: Functional Testing. The functional testing phase was conducted on Unit TD-02 (an intact reference sample) to characterize the optical performance of the LumiEdge 1600G-LR without compromising the unit subjected to destructive die-level analysis. Functional tests included:
• Insertion loss measurement at operating wavelength (C-band, 1530–1565 nm)
• Return loss measurement
• Polarization-dependent loss (PDL) measurement
• Spectral response characterization
• Coherent detection performance measurement (constellation quality, error vector magnitude, signal-to-noise ratio)
• Grating coupler efficiency estimation (derived from insertion loss measurements and comparison to reference coupler designs)
The functional test data are reported in the Benchmark report at Section 7 (Functional Performance Characterization) and are relevant to both the literal infringement analysis (confirming that the accused product achieves the claimed functional parameters) and the doctrine of equivalents analysis (demonstrating that the accused design achieves substantially the same result as the claimed structures).
III. PRODUCT OVERVIEW — LUMICORE LumiEdge 1600G-LR
A. Product Description
The LumiEdge 1600G-LR is a 1600G (1.6 Tbps aggregate) long-reach coherent optical transceiver module designed for hyperscale data-center interconnect ("DCI") and telecom metro/long-haul applications. It represents Lumicore's highest-bandwidth product in its accused product line and is the most recently launched accused product in this litigation. The module is designed to provide high-capacity, low-latency optical connectivity over distances up to 80 kilometers, utilizing dual-polarization 16-QAM modulation on each of multiple wavelength channels carried on a single fiber pair.
The LumiEdge 1600G-LR is housed in an OSFP (Octal Small Form Factor Pluggable) form factor, consistent with the industry-standard OSFP Multi-Source Agreement for next-generation high-bandwidth transceiver modules. The module utilizes LC duplex optical connectors for the line-side optical interface and a high-density electrical connector (compliant with the OSFP MSA electrical interface specification) for the host-side electrical interface. The module operates at a nominal power consumption of 28W, as specified in Lumicore's product datasheet (LumiEdge 1600G-LR Datasheet, Rev. A, dated September 2023).
The LumiEdge 1600G-LR is designed to compete directly with OWS's OWS-1600DR transceiver module family, which was launched in Q2 2023 and represents OWS's current flagship coherent transceiver product. Both products target the same customer base (hyperscale cloud service providers and tier-1 telecom operators), serve the same applications (DCI and metro/long-haul), and offer comparable performance specifications. The competitive overlap between the LumiEdge 1600G-LR and the OWS-1600DR is significant to the lost-profits damages analysis, as discussed in Section VIII.A below.
B. Market Context
The LumiEdge 1600G-LR was commercially launched by Lumicore in Q4 2023, with first customer shipments occurring in October 2023 according to Lumicore's earnings call transcript for the quarter ended December 31, 2023. The product generated estimated FY 2023 revenue of $41.7 million, representing a partial-year figure (approximately one quarter of revenue) given the Q4 2023 launch timing. Lumicore's management characterized the LumiEdge 1600G-LR as a "transformational product" during the Q4 2023 earnings call and indicated strong customer demand driven by accelerating hyperscale data-center buildouts and the transition to 1.6T-and-beyond optical networking infrastructure.
Total projected accused-product revenue across all three accused products — the LumiLink 400G-ZR+, the LumiLink 800G-DR8, and the LumiEdge 1600G-LR — through Q4 2025 is approximately $714.6 million per Dr. Lawrence Keating's (Meridian Economic Consulting Group, LLC) preliminary damages analysis. Of this total, the LumiEdge 1600G-LR is projected to contribute an increasing proportion of revenue as the 400G-ZR+ product reaches end-of-life and the 800G-DR8 transitions to a legacy platform. Dr. Keating's analysis projects LumiEdge 1600G-LR revenue of approximately $195 million in FY 2024 and $260 million in FY 2025, representing an anticipated compound annual growth rate consistent with broader industry forecasts for 1.6T coherent transceiver adoption.
This product is accused of infringing the '193 Patent and the '015 Patent. Notably, the '847 Patent and the '562 Patent are not asserted against the LumiEdge 1600G-LR. Those patents are asserted only against the LumiLink 400G-ZR+ and LumiLink 800G-DR8 products, based on specific thermal management and wavelength-division multiplexing features present in those earlier-generation products that are addressed differently in the LumiEdge 1600G-LR architecture.
C. Key Technical Architecture (Per Teardown)
The Benchmark teardown reveals the following key architectural features of the LumiEdge 1600G-LR, each of which is relevant to the infringement analysis for one or both of the asserted patents:
Silicon Photonic Integrated Circuit (PIC) Die. The core of the LumiEdge 1600G-LR is a silicon photonic integrated circuit die that contains the coherent transceiver optical engine. The PIC die measures approximately 17.2 mm × 12.8 mm and is fabricated using a multi-layer silicon photonic process. The die incorporates optical modulators (Mach-Zehnder modulators for coherent modulation), waveguide routing structures, grating couplers for fiber-to-chip optical coupling, coherent detection optics (including optical hybrids and balanced photodetectors), and polarization handling elements. The PIC die is the primary structural element relevant to both the '193 Patent and the '015 Patent claim limitations.
Grating Coupler Structures. The PIC die incorporates grating coupler structures at the fiber-to-chip optical interface. These grating couplers are the primary structures relevant to the '015 Patent infringement analysis. The teardown reveals a periodic grating pattern etched into the silicon waveguide layer, with specific geometric parameters (grating period, etch depth, fill factor, and polarization-handling geometry) that correspond to the claimed polarization-diverse grating coupler. The grating coupler design is discussed in detail in Section V below.
Coherent Detection Architecture. The LumiEdge 1600G-LR PIC die incorporates a coherent detection architecture that includes polarization beam splitting, 90-degree optical hybrids, and balanced photodetector arrays. This architecture enables the recovery of amplitude and phase information from coherent optical signals and is central to the '193 Patent infringement analysis. The coherent detection module design, including the specific structural variants identified in the teardown, is discussed in detail in Section IV below.
Electronic IC (EIC). The module incorporates a separate electronic integrated circuit die (EIC) that performs digital signal processing ("DSP") functions, including forward error correction, equalization, and modulation/demodulation. The EIC is manufactured by a third-party semiconductor foundry (believed to be Drayton Holdings, based on die markings and process node characteristics observed in the teardown) and is connected to the PIC die through a high-density electrical interconnect. The EIC is not directly implicated by the asserted patent claims, which are directed to the photonic structures rather than the electronic signal processing.
Thermal Management Structures. The module incorporates thermal management structures including a copper heat spreader, thermal interface materials (phase-change thermal pads), and a heat-sink assembly integrated into the OSFP housing lid. While these structures were documented by Benchmark for completeness, they are not directly relevant to the asserted claims for the LumiEdge 1600G-LR. The '562 Patent, which contains thermal-management claims, is not asserted against this product.
IV. CLAIM-LIMITATION CROSS-REFERENCE ANALYSIS — '193 PATENT (U.S. Patent No. 10,891,193)
A. Patent Overview
The '193 Patent, titled "High-Bandwidth Coherent Optical Transceiver Integrated on Silicon Substrate," was filed on April 7, 2017, claiming priority to Provisional Application No. 62/499,117, also filed on April 7, 2017. The patent issued on January 12, 2021. The original and current assignee is Optiwave Semiconductor Corp. The named inventors include Dr. Jian-Wei Huang, who serves as OWS's Chief Technology Officer and is expected to be a fact witness at trial regarding the conception and development of the patented technology.
The '193 Patent is generally directed to a coherent optical transceiver architecture that is integrated on a silicon substrate using semiconductor fabrication processes. The patent describes a silicon photonic platform that enables high-bandwidth coherent optical communication by integrating optical modulators, coherent detection optics, waveguides, and polarization-handling elements on a single silicon-based chip. The claimed invention addresses the longstanding challenge in the field of achieving high-performance coherent transceiver functionality within the constraints of silicon photonic fabrication, which historically has been limited in its ability to support the complex optical functions required for coherent detection.
The following claims of the '193 Patent are asserted against the LumiEdge 1600G-LR: Claims 1, 3, 7, 10, 15, and 18. Claims 1 and 10 are independent claims. Claims 3 and 7 depend from Claim 1. Claim 15 depends from Claim 10. Claim 18 depends from Claim 15.
B. Claim 1 — Literal Infringement Mapping
Independent Claim 1 of the '193 Patent recites a coherent optical transceiver module integrated on a silicon substrate, comprising a plurality of specified structural elements. The following analysis maps each limitation of Claim 1 to the corresponding structures and components identified in the Benchmark teardown of the LumiEdge 1600G-LR.
Preamble: "A coherent optical transceiver module." The LumiEdge 1600G-LR is a coherent optical transceiver module. Benchmark's functional testing confirms that the module performs coherent modulation and detection of optical signals, employing dual-polarization quadrature amplitude modulation (DP-16QAM) to encode and decode data onto optical carrier signals. The product datasheet, marketing materials, and functional test results all confirm that the LumiEdge 1600G-LR is a coherent optical transceiver module within any reasonable construction of this preamble term. Even if the preamble is construed as a limitation (which OWS does not concede), this element is plainly met.
Limitation 1(a): "a silicon substrate." The Benchmark teardown, through cross-sectional SEM analysis and EDS material composition testing, confirms that the PIC die at the core of the LumiEdge 1600G-LR is fabricated on a silicon substrate. EDS spectra obtained at the substrate layer confirm silicon as the primary elemental composition, with a silicon dioxide buried oxide ("box") layer and silicon device layers consistent with a silicon-on-insulator ("SOI") fabrication platform. The silicon substrate has a thickness of approximately 725 μm, consistent with standard 200 mm or 300 mm SOI wafer thicknesses used in commercial silicon photonic foundry processes. See Benchmark Report, Section 6.2, Figures 6-4 through 6-8 (cross-sectional SEM images of substrate and layer stack).
This limitation implicates the disputed claim construction term "integrated on a silicon substrate." OWS proposes the construction "formed on or within a silicon-based wafer using semiconductor fabrication processes," while Lumicore proposes the narrower construction "monolithically fabricated on a single silicon die without hybrid bonding or heterogeneous integration." The Benchmark cross-sectional analysis is central to resolving this factual question. Specifically, the cross-sectional SEM images at the boundary between the silicon waveguide layer and the germanium photodetector layer reveal an interface that could be interpreted as either a heterogeneously integrated layer or a monolithically grown epitaxial germanium layer. The distinction is significant: if the germanium photodetectors are epitaxially grown on the silicon substrate (as in standard Drayton Holdings or IMEC silicon photonic processes), the structure would satisfy even Lumicore's narrow construction. If, however, the germanium photodetector layer is bonded to the silicon substrate through a wafer-bonding process, Lumicore may argue that its narrow construction is not satisfied. Benchmark's analysis, based on the interface morphology and EDS composition profile at the boundary, indicates that the germanium layer is most likely epitaxially grown, as the interface shows a gradual compositional transition rather than the abrupt interface and bonding oxide characteristic of wafer bonding. This finding supports literal infringement under either proposed construction. However, this issue should be confirmed through analysis of Lumicore's fabrication process documentation when produced in discovery.
Limitation 1(b): "an optical modulator array formed on the silicon substrate, the optical modulator array comprising a plurality of Mach-Zehnder modulators configured to modulate an optical carrier signal." The Benchmark teardown identifies an array of Mach-Zehnder interferometer ("MZI") modulator structures on the PIC die, located in the transmitter region of the coherent transceiver engine. Optical microscopy at 100x magnification reveals a regular array of MZI structures, each comprising input and output waveguide branches, phase-shifting elements, and waveguide combiners. The number of MZI modulators identified is consistent with the dual-polarization IQ modulation architecture required for DP-16QAM coherent modulation: two MZI modulators per quadrature (I and Q) per polarization (TE and TM), yielding eight MZI modulators in total. SEM imaging at higher magnifications (1,000x and 5,000x) reveals the specific geometry of the phase-shifting elements, which appear to be carrier-depletion type PN junction modulators implemented within the silicon rib waveguide structure. See Benchmark Report, Section 5.3, Figures 5-12 through 5-18 (MZI modulator array images).
Limitation 1(c): "a waveguide network formed on the silicon substrate, the waveguide network optically coupling the optical modulator array to at least one fiber coupling interface." The PIC die contains an extensive network of silicon waveguides routing optical signals between the various functional blocks, including from the modulator array to the grating coupler interfaces (which serve as the fiber coupling interface). The waveguide network is visible in die-level optical microscopy images and is further characterized through SEM imaging. Waveguide dimensions measured from SEM cross-sections are approximately 450 nm width × 220 nm height, consistent with standard single-mode silicon strip waveguides in commercial silicon photonic processes. See Benchmark Report, Section 5.4, Figures 5-19 through 5-24 (waveguide routing images and dimensional measurements).
Limitation 1(d): "a coherent detection module formed on the silicon substrate, the coherent detection module comprising at least one optical hybrid and a plurality of balanced photodetectors, the coherent detection module configured to recover amplitude and phase information from received optical signals." The receiver region of the PIC die contains a coherent detection module comprising optical hybrid structures and balanced photodetector pairs. The 90-degree optical hybrid structures are identified through SEM imaging as multi-mode interference ("MMI") couplers configured as 2×4 or 4×4 MMI hybrids. The balanced photodetectors are germanium-on-silicon photodiodes arranged in matched pairs. Functional testing confirms that the coherent detection module recovers both amplitude and phase information from received optical signals, as evidenced by the constellation diagrams and error vector magnitude measurements obtained during performance characterization. See Benchmark Report, Section 5.5, Figures 5-25 through 5-33 (coherent detection module images), and Section 7.3, Tables 7-4 through 7-6 (coherent detection performance data).
This limitation is central to the DOE analysis for dependent Claims 3 and 7, as discussed in Section IV.C below.
Limitation 1(e): "a polarization handling element formed on the silicon substrate, the polarization handling element configured to separate received optical signals into at least two orthogonal polarization components." The PIC die incorporates a polarization handling element in the receiver optical path, upstream of the coherent detection module. SEM imaging reveals a polarization beam splitter/rotator ("PSR") structure implemented using a waveguide taper and mode-coupling geometry. The PSR separates incoming optical signals into TE and TM polarization components and rotates the TM component to TE polarization for processing by the coherent detection module. See Benchmark Report, Section 5.6, Figures 5-34 through 5-38 (polarization handling element images).
Based on the foregoing analysis, each limitation of independent Claim 1 of the '193 Patent is met by corresponding structures identified in the LumiEdge 1600G-LR teardown. The literal infringement case for Claim 1 is strong under OWS's proposed claim constructions and remains viable even under Lumicore's narrower proposed constructions, subject to confirmation of the integration methodology through discovery of fabrication process documentation.
C. Claims 3 and 7 — Literal Infringement and Doctrine of Equivalents
Claims 3 and 7 are dependent claims that depend from Claim 1, incorporating all limitations of Claim 1 and adding further limitations directed to the "coherent detection module."
Claim 3 adds the limitation: "wherein the coherent detection module comprises a polarization-diverse coherent receiver with separate I/Q detection paths for each polarization component." The LumiEdge 1600G-LR's coherent detection module, as identified in the teardown, provides separate I (in-phase) and Q (quadrature) detection paths for each of the two orthogonal polarization components (TE-X and TE-Y, following polarization rotation). The teardown identifies four sets of balanced photodetector pairs corresponding to I-X, Q-X, I-Y, and Q-Y channels, confirming the presence of separate I/Q detection paths for each polarization component. This limitation appears to be literally satisfied.
Claim 7 adds the limitation: "wherein the at least one optical hybrid comprises a 90-degree optical hybrid implemented as a multi-mode interference coupler with at least four output ports." The teardown identifies the optical hybrid structures as MMI couplers. However, Benchmark's analysis reveals a design variant in the LumiEdge 1600G-LR's optical hybrid implementation that warrants careful analysis. Specifically, the LumiEdge 1600G-LR appears to use a cascaded 2×2 MMI coupler arrangement rather than a single 2×4 or 4×4 MMI coupler to achieve the 90-degree hybrid function. The cascaded arrangement produces four output ports in aggregate, but the individual MMI couplers each have only two output ports. Whether this cascaded architecture literally satisfies the claim limitation "a multi-mode interference coupler with at least four output ports" depends on the construction of this phrase — specifically, whether "a multi-mode interference coupler" refers to a single physical MMI coupler or to a functional unit that may comprise multiple cascaded MMI couplers.
Literal Infringement Analysis. Under OWS's proposed interpretation — that "a multi-mode interference coupler with at least four output ports" encompasses any MMI-coupler-based structure that provides at least four output ports, including cascaded configurations — the LumiEdge 1600G-LR literally satisfies this limitation. Under Lumicore's anticipated interpretation — that the claim requires a single, unitary MMI coupler with at least four output ports — literal infringement of Claim 7 may not be established. This issue has been flagged for the claim construction briefing and is addressed in the Markman Hearing Preparation Memorandum (internal, target February 28, 2025).
Doctrine of Equivalents Analysis. In the event that the Court adopts Lumicore's narrower interpretation and literal infringement of Claim 7 is not established, OWS asserts infringement under the doctrine of equivalents. The accused cascaded MMI coupler structure in the LumiEdge 1600G-LR:
• Performs substantially the same function: The cascaded 2×2 MMI coupler arrangement performs the function of a 90-degree optical hybrid — it mixes the received signal with a local oscillator reference to produce four output signals having 0°, 90°, 180°, and 270° relative phase offsets, enabling coherent I/Q detection.
• In substantially the same way: The cascaded arrangement uses multi-mode interference within MMI coupler waveguide structures to achieve the required phase relationships between output ports. The physical mechanism of operation (self-imaging in multi-mode waveguides) is identical to that of a single 4-output MMI coupler. The cascading merely distributes the splitting and phase-shifting functions across two stages rather than one.
• To achieve substantially the same result: The cascaded structure produces four output signals with the required 90-degree phase offsets, enabling recovery of the I and Q components of the coherent optical signal with the same fidelity as a single 4-output MMI hybrid. Benchmark's functional testing confirms that the coherent detection performance of the LumiEdge 1600G-LR (error vector magnitude, constellation quality) is comparable to or exceeds that of reference coherent receivers using single 4-output MMI hybrids.
Prosecution History Estoppel. The application of the doctrine of equivalents to Claim 7 must be analyzed in light of the prosecution history of the '193 Patent. During prosecution, Claim 7 was narrowed in response to a § 102 anticipation rejection over Takahashi et al. ("Dense WDM Silicon Photonic MUX," IEEE Photonics Technology Letters, March 2014). Specifically, the phrase "at least four output ports" was added by amendment to overcome the Takahashi reference, which disclosed a 2×2 MMI coupler with only two output ports. The narrowing amendment raises the question of whether prosecution history estoppel under Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002), bars application of the doctrine of equivalents to encompass the cascaded 2×2 MMI structure in the LumiEdge 1600G-LR.
The Prosecution History Estoppel Analysis — '193 Patent (internal memo dated October 10, 2024) concludes that the Festo presumption is likely rebutted under the "unforeseeability" exception. At the time of the narrowing amendment (January 2019), the cascaded 2×2 MMI coupler arrangement used in the LumiEdge 1600G-LR was not a foreseeable design-around that the applicant could have reasonably been expected to capture through claim language. The cascaded approach, while known in the literature for other applications, had not been demonstrated in a silicon photonic coherent transceiver context at the time of the amendment. Additionally, the amendment was made to distinguish the two-output-port device of Takahashi, and the rationale for the amendment (distinguishing a two-output device from a four-output device) does not bear a tangential or peripheral relationship to the equivalent at issue (a cascaded arrangement that also provides four outputs). This analysis should be further developed in the context of Dr. Ashford's expert report.
Cross-reference is also made to the Doctrine of Equivalents Analysis Memorandum (internal, September 5, 2024), which provides additional discussion of the function-way-result test and the Vitronics / Johnson & Johnston all-limitations rule considerations.
D. Claim 10 — Literal Infringement Mapping
Independent Claim 10 of the '193 Patent is directed to a method of coherent optical communication using a transceiver integrated on a silicon substrate. The following analysis maps each limitation of Claim 10 to the structures and operational characteristics identified in the Benchmark teardown.
Preamble: "A method of coherent optical communication, comprising." The LumiEdge 1600G-LR performs coherent optical communication as its core function. Functional testing by Benchmark confirms the execution of coherent modulation and detection processes.
Limitation 10(a): "providing a coherent optical transceiver module integrated on a silicon substrate, the module comprising an optical modulator array, a waveguide network, and a coherent detection module." This limitation is a "providing" step that recites the same structural elements addressed in the Claim 1 analysis above. As established in Section IV.B, the LumiEdge 1600G-LR incorporates all of these structural elements on its silicon PIC die. The same teardown findings and evidence cited in the Claim 1 analysis apply here.
Limitation 10(b): "modulating, by the optical modulator array, at least one optical carrier signal to encode data onto the optical carrier signal using Ridgeline & Co. modulation." Benchmark's functional testing confirms that the LumiEdge 1600G-LR modulates optical carrier signals using DP-16QAM coherent modulation. The modulation is performed by the MZI modulator array identified on the PIC die. The modulation format and data encoding are confirmed through electrical-domain analysis of the modulated signal and through optical-domain constellation analysis. See Benchmark Report, Section 7.2, Figures 7-3 through 7-5 (transmitter modulation characterization).
Limitation 10(c): "coupling, via a fiber coupling interface, the modulated optical carrier signal to an optical fiber." The modulated optical signals are coupled from the PIC die to the external optical fiber through the grating coupler structures that serve as the fiber coupling interface. Benchmark confirmed the optical coupling through insertion loss measurements and by verifying that modulated optical power was present at the module's LC connector output. See Benchmark Report, Section 7.1, Table 7-1 (insertion loss measurements).
Limitation 10(d): "receiving, via the fiber coupling interface, an incoming modulated optical signal from an optical fiber." The same fiber coupling interface (or a separate grating coupler dedicated to the receiver path, depending on the architecture) receives incoming optical signals. The teardown confirms the presence of dedicated receiver-path grating couplers on the PIC die, and functional testing confirms reception of incoming signal optical signals. See Benchmark Report, Section 5.2, Figure 5-10 (receiver-path grating coupler identification).
Limitation 10(e): "recovering, by the coherent detection module, amplitude and phase information from the incoming modulated optical signal." As established in the Claim 1 analysis (Limitation 1(d)), the coherent detection module on the PIC die recovers amplitude and phase information from received optical signals. This is confirmed by functional testing demonstrating successful coherent demodulation with constellation diagrams showing recovery of 16-QAM symbols. See Benchmark Report, Section 7.3, Figures 7-6 through 7-9 (receiver coherent detection performance).
Based on the foregoing analysis, each limitation of independent Claim 10 is met by the corresponding structures and operations identified in the LumiEdge 1600G-LR teardown. The literal infringement case for Claim 10 is strong.
E. Claim 15 — Literal Infringement Mapping (Means-Plus-Function Considerations)
Claim 15 depends from Claim 10 and adds the limitation: "wherein coupling the modulated optical carrier signal to the optical fiber comprises coupling by means for fiber-to-chip optical coupling integrated on the silicon substrate."
The Means-Plus-Function Analysis Memorandum (internal, dated October 5, 2024) identifies the phrase "means for fiber-to-chip optical coupling" as a potentially means-plus-function term under 35 U.S.C. § 112(f). The use of the word "means" coupled with a functional description ("fiber-to-chip optical coupling") and the absence of sufficient structural recitation in the claim language itself triggers the presumption that § 112(f) applies. OWS does not contest the application of § 112(f) to this term.
Under § 112(f), the "means for fiber-to-chip optical coupling" is construed to cover the corresponding structure disclosed in the '193 Patent specification, and equivalents thereof. The '193 Patent specification discloses two corresponding structures for the "means for fiber-to-chip optical coupling":
1. A grating coupler, described at col. 7, ll. 14–35 and illustrated in Figures 4A–4C of the '193 Patent.
2. An edge coupler (also referred to as a "butt coupler" or "spot-size converter"), described at col. 7, ll. 36–48 and illustrated in Figure 4D of the '193 Patent.
The Benchmark teardown identifies grating coupler structures at the fiber-to-chip interface of the LumiEdge 1600G-LR PIC die. As discussed in Section V (regarding the '015 Patent claims), the grating coupler is characterized in detail through SEM imaging, cross-sectional analysis, and functional testing. The grating coupler structure identified in the LumiEdge 1600G-LR falls within the scope of the corresponding structure disclosed in the '193 Patent specification (i.e., a grating coupler). Accordingly, this limitation is satisfied.
Even if the specific grating coupler design in the LumiEdge 1600G-LR differs in certain design parameters (e.g., grating period, etch depth, fill factor) from the specific grating coupler embodiment illustrated in the '193 Patent Figures 4A–4C, the § 112(f) analysis requires only that the accused structure be the same structure disclosed in the specification or an equivalent structure. A grating coupler is a grating coupler — variations in design parameters do not change the fundamental structural identity. See Odetics, Inc. v. Storage Tech. Corp., 185 F.3d 1259, 1267 (Fed. Cir. 1999) (equivalents under § 112(f) are structural equivalents, not equivalents under the doctrine of equivalents).
F. Claim 18 — Literal Infringement Mapping
Claim 18 depends from Claim 15 (which depends from Claim 10) and adds the limitation: "wherein the coherent optical transceiver module further comprises a polarization beam splitter integrated on the silicon substrate and configured to separate received optical signals into orthogonal polarization components prior to detection by the coherent detection module."
The Benchmark teardown identifies a polarization beam splitter/rotator ("PSR") structure on the PIC die, as discussed in the Claim 1 Limitation 1(e) analysis above. The PSR is integrated on the silicon substrate and is located in the receiver optical path upstream of the coherent detection module, consistent with the claim language specifying that the polarization separation occurs "prior to detection by the coherent detection module." SEM images of the PSR structure show a waveguide taper geometry that separates TE and TM polarization modes using mode-evolution coupling. See Benchmark Report, Section 5.6, Figures 5-34 through 5-38.
The PSR identified in the teardown is a "polarization beam splitter" as recited in the claim. Although the claim does not also recite a polarization rotator, the fact that the LumiEdge 1600G-LR's PSR also rotates the TM component to TE polarization after splitting does not defeat infringement — the PSR performs the claimed function (splitting into orthogonal polarization components) and additionally performs rotation, which is an additional function not excluded by the claim language. Under the well-established principle that the presence of additional, unclaimed features does not negate infringement, the PSR in the LumiEdge 1600G-LR satisfies this limitation. See Pemberton Partners LLC v. F. Hoffmann-La Roche Ltd., 580 F.3d 1340, 1374 (Fed. Cir. 2009).
G. Summary Table — '193 Patent Claims vs. LumiEdge 1600G-LR
The following table summarizes the claim-limitation cross-reference analysis for all asserted claims of the '193 Patent against the LumiEdge 1600G-LR:
V. CLAIM-LIMITATION CROSS-REFERENCE ANALYSIS — '015 PATENT (U.S. Patent No. 11,402,015)
A. Patent Overview
The '015 Patent, titled "Polarization-Diverse Grating Coupler for Silicon Photonic Transceivers," was filed on August 30, 2019, claiming priority to Provisional Application No. 62/499,117, filed April 7, 2017. The '015 Patent thus shares the same provisional priority date as the '193 Patent. The patent issued on August 2, 2022. The original and current assignee is Optiwave Semiconductor Corp. The named inventors include Dr. Jian-Wei Huang and Dr. Mei-Ling Cho, both of OWS's photonics research group.
The '015 Patent is directed to a polarization-diverse grating coupler structure for silicon photonic transceivers that enables efficient coupling of light from an optical fiber to a silicon photonic chip while handling both orthogonal polarization states (TE and TM). The claimed grating coupler design addresses the well-known polarization sensitivity problem in conventional one-dimensional grating couplers, which typically couple only a single polarization state efficiently. The '015 Patent discloses a two-dimensional grating coupler geometry that simultaneously captures both polarization states and routes them to separate waveguide outputs, enabling polarization-diverse operation essential for coherent optical transceivers.
The following claims of the '015 Patent are asserted against the LumiEdge 1600G-LR: Claims 1, 5, 8, 12, and 16. Claim 1 is an independent claim. Claims 5 and 8 depend from Claim 1. Claim 12 depends from Claim 8. Claim 16 depends from Claim 1.
B. Claim 1 — Literal Infringement Mapping
Independent Claim 1 of the '015 Patent recites a polarization-diverse grating coupler for a silicon photonic transceiver, comprising specified structural elements. The following analysis maps each limitation to the structures identified in the Benchmark teardown.
Preamble: "A polarization-diverse grating coupler for a silicon photonic transceiver, comprising." The LumiEdge 1600G-LR incorporates grating coupler structures on its silicon PIC die that serve as the fiber-to-chip optical coupling interface for the coherent transceiver. As discussed below, the grating coupler identified in the teardown is a polarization-diverse design, consistent with the preamble.
Limitation 1(a): "a grating region formed in a waveguide layer on a silicon substrate, the grating region comprising a periodic pattern of features configured to diffract light from an optical fiber into the waveguide layer." The Benchmark teardown identifies a grating region on the PIC die at the fiber-to-chip interface. SEM imaging at 5,000x and 10,000x magnification reveals a periodic pattern of etched features in the silicon waveguide layer. The grating region is positioned beneath the fiber attachment point and is configured to diffract light from the optical fiber (incident at an angle of approximately 8–12 degrees from vertical, based on the fiber attachment geometry observed in the teardown) into the in-plane silicon waveguide layer. The grating is formed in the same waveguide layer (220 nm silicon device layer) that constitutes the silicon photonic waveguide structures throughout the PIC die, and this waveguide layer is formed on the silicon substrate (SOI platform). See Benchmark Report, Section 5.2, Figures 5-7 through 5-11 (grating region overview images), and Section 6.3, Figures 6-9 through 6-14 (cross-sectional analysis of grating features).
The grating period, as measured from SEM images, is approximately 610 nm ± 5 nm. The etch depth is approximately 70 nm (partial etch of the 220 nm silicon device layer). The fill factor (ratio of etched to unetched regions) is approximately 0.50. These parameters are consistent with a grating coupler optimized for C-band (1550 nm center wavelength) operation on a standard SOI platform.
Limitation 1(b): "wherein the periodic pattern of features is arranged in a two-dimensional array such that the grating region is configured to couple light of a first polarization state into a first waveguide output and light of a second polarization state, orthogonal to the first polarization state, into a second waveguide output." This limitation contains the disputed claim construction term "polarization-diverse grating coupler," and the specific structural requirement of a "two-dimensional array" of features.
The Benchmark SEM imagery reveals that the grating coupler in the LumiEdge 1600G-LR uses a two-dimensional pattern of features — specifically, a grid-like arrangement of rectangular or square features (holes or posts) arranged in both the x and y directions, rather than a one-dimensional array of parallel lines. This two-dimensional geometry is characteristic of a polarization-diverse grating coupler design that simultaneously captures both TE and TM polarization components of the incoming fiber light and routes them to two separate waveguide outputs oriented at approximately 90 degrees to each other.
SEM images at 25,000x magnification clearly show the two-dimensional periodicity of the grating features. The grating periods in the two orthogonal directions are measured to be approximately 610 nm (x-direction) and 615 nm (y-direction), with the slight asymmetry likely intentional to optimize polarization splitting performance. Two waveguide outputs are observed emanating from the grating region at approximately 90-degree angles, consistent with the claim requirement that light of one polarization state is coupled into a first waveguide output and light of the orthogonal polarization state is coupled into a second waveguide output. See Benchmark Report, Section 5.2, Figures 5-8 through 5-11 (grating coupler plan-view SEM images), and Section 6.3, Figures 6-9 through 6-14 (cross-sectional analysis).
Analysis Under Competing Claim Constructions. OWS proposes that "polarization-diverse grating coupler" be construed as "a grating coupler capable of coupling light of two orthogonal polarization states." Under this construction, the LumiEdge 1600G-LR's grating coupler plainly satisfies the limitation, as the two-dimensional grating pattern and dual waveguide outputs confirm the ability to couple both orthogonal polarization states.
Lumicore proposes the narrower construction "a two-dimensional grating coupler with a polarization-splitting element that simultaneously couples TE and TM modes." This construction adds two requirements beyond OWS's proposal: (1) the presence of a "polarization-splitting element" as a distinct structural feature, and (2) the requirement of "simultaneous" coupling of TE and TM modes.
With respect to the "polarization-splitting element" requirement, the two-dimensional grating structure itself functions as the polarization-splitting element — the two-dimensional periodicity inherently splits the two polarization states by diffracting them into different waveguide outputs. Whether Lumicore's construction requires a separate, identifiable "polarization-splitting element" distinct from the grating itself is a question of claim construction. If the grating structure itself qualifies as the "polarization-splitting element" (as OWS contends it should), then this requirement is satisfied. If Lumicore's construction requires an additional, separate element, the literal infringement analysis would depend on whether any additional structural feature in the grating coupler region serves this function.
With respect to the "simultaneous" coupling requirement, the two-dimensional grating coupler in the LumiEdge 1600G-LR operates by simultaneously diffracting both polarization components — the TE-polarized light couples into the waveguide output oriented along one axis, and the TM-polarized light (which appears as TE-like polarization along the orthogonal axis due to the 2D grating geometry) couples into the waveguide output oriented along the perpendicular axis. This simultaneous operation is inherent in the physics of a two-dimensional grating coupler and is confirmed by Benchmark's functional testing showing simultaneous coupling of both polarization states. Accordingly, even under Lumicore's narrower construction, the "simultaneous" coupling requirement is satisfied.
Limitation 1(c): "wherein the first waveguide output and the second waveguide output are coupled to a coherent transceiver optical engine." The two waveguide outputs from the grating coupler are traced through the waveguide routing network on the PIC die to the coherent detection module, which is part of the coherent transceiver optical engine. The waveguide routing is visible in die-level optical microscopy images and confirmed through SEM imaging at the routing junctions. See Benchmark Report, Section 5.4, Figures 5-19 through 5-24 (waveguide routing from grating coupler to coherent detection module).
Based on the foregoing analysis, each limitation of independent Claim 1 of the '015 Patent is met by corresponding structures identified in the LumiEdge 1600G-LR teardown. The literal infringement case for Claim 1 is strong under both competing claim constructions.
C. Claims 5 and 8 — Literal Infringement Mapping
Claim 5 depends from Claim 1 and adds the limitation: "wherein the grating region has an etch depth between 50 nm and 100 nm and a fill factor between 0.40 and 0.60." Benchmark's cross-sectional SEM analysis of the grating coupler region measures an etch depth of approximately 70 nm and a fill factor of approximately 0.50. Both values fall within the ranges specified in Claim 5. The etch depth was determined by FIB cross-sectioning at three separate locations across the grating region, yielding consistent measurements of 68 nm, 71 nm, and 72 nm (average: 70.3 nm). The fill factor was determined by measurement of the etched and unetched feature widths from plan-view SEM images at 25,000x magnification across multiple unit cells. See Benchmark Report, Section 6.3, Figures 6-11 through 6-14 (cross-sectional etch depth measurements), and Section 5.2, Table 5-2 (fill factor measurements). This limitation is literally satisfied.
Claim 8 depends from Claim 1 and adds the limitation: "wherein the grating region is configured to provide a coupling efficiency of at least -3 dB for each of the first and second polarization states at a center wavelength within the C-band." Benchmark's functional testing of the grating coupler, derived from insertion loss measurements and component-level loss analysis, estimates a coupling efficiency of approximately -2.4 dB for the TE polarization state and approximately -2.7 dB for the TM polarization state at a center wavelength of 1550 nm. Both values exceed the -3 dB threshold specified in Claim 8. The coupling efficiency measurements were obtained by deconvolving the total fiber-to-fiber insertion loss into its component contributions (grating coupler loss, waveguide propagation loss, modulator insertion loss, etc.) using reference measurements and component-level characterization. See Benchmark Report, Section 7.1, Tables 7-1 through 7-3 (insertion loss breakdown and coupling efficiency estimates). This limitation is literally satisfied.
D. Claim 12 — Literal Infringement and Doctrine of Equivalents
Claim 12 depends from Claim 8 (which depends from Claim 1) and adds the limitation: "wherein the grating region further comprises a two-dimensional sub-wavelength grating overlaid on the periodic pattern of features, the sub-wavelength grating configured to reduce back-reflection and improve polarization extinction ratio."
Literal Infringement Analysis. Benchmark's SEM analysis of the grating coupler region in the LumiEdge 1600G-LR reveals, in addition to the primary grating pattern (with ~610 nm period), a finer-scale secondary pattern of features within the grating region. This secondary pattern has a feature periodicity of approximately 280 nm, which is below the operating wavelength of 1550 nm (and also below the effective wavelength in silicon, λ/n ≈ 1550/3.47 ≈ 447 nm) and thus qualifies as "sub-wavelength" in the context of the operating medium. The secondary pattern is visible in SEM images at 50,000x magnification and appears to be a set of small rectangular features etched within the primary grating unit cells. See Benchmark Report, Section 5.2, Figures 5-9 through 5-11 (high-magnification SEM of sub-wavelength features).
The key question for literal infringement is whether this secondary pattern constitutes a "two-dimensional sub-wavelength grating overlaid on the periodic pattern of features" as clai

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