Contract analysis

I. Executive Summary This memorandum presents a pre-suit infringement analysis evaluating whether Lumos Photonics, Inc. ("Lumos" or "LPI") infringes asserted Claims 1, 5, 8, and 13 of U.S. Patent No. 11,312,890 ("the '890 Patent") through its LumosBridge™ 800G Optical Engine and LumosEdge™ 400ZR+ Pluggable Transceiver products. This memorandum has been prepared at the direction of counsel in anticipation of litigatio

II. Background A. The '890 Patent Overview The '890 Patent is titled "Driver Circuit Architecture for High-Speed Silicon Photonic Mach-Zehnder Modulators" and was issued as U.S. Patent No. 11,312,890 on April 26, 2022. The underlying patent application was filed on November 15, 2018. The named inventors are Dr. Kevin Fong and Rajesh Iyer, both of whom are employees of OWS. Dr. Fong serves as OWS's Chief Technology Of

III. Claim-by-Claim Infringement Analysis A. Claim 1 (Independent Claim)

1. Claim Language Claim 1 of the '890 Patent recites as follows:

1. An optical modulator system, comprising: (a) a silicon photonic Mach-Zehnder modulator formed on a substrate; (b) a pre-emphasis equalization stage electrically co-integrated with the modulator on a common substrate, wherein the equalization stage is configured to receive a data signal and to generate a pre-emphasized drive signal; (c) wherein the equalization stage is configured to compensate for frequency-depend

2. Element-by-Element Analysis Element (a): "A silicon photonic Mach-Zehnder modulator formed on a substrate." Lumos's LumosBridge 800G Optical Engine and LumosEdge 400ZR+ Pluggable Transceiver each include a silicon photonic Mach-Zehnder modulator formed on a silicon-on-insulator substrate. This is confirmed by Lumos's published product datasheets, which describe the products as incorporating "high-performance silic

3. Claim 1 Overall Assessment At least two elements of Claim 1 — element (b) ("co-integrated with the modulator on a common substrate") and element (d) ("electrical connections . . . formed within the substrate") — present serious infringement vulnerabilities. Both limitations point to a common architectural distinction between the claimed co-integrated, monolithic approach and Lumos's multi-chip, flip-chip bonded ap

5. The optical modulator system of claim 1, wherein the pre-emphasis equalization stage comprises a finite impulse response (FIR) filter with programmable tap coefficients. Based on Lumos's published technical papers and conference presentations, the pre-emphasis equalization stage in Lumos's CMOS driver die implements an FIR-based equalizer architecture with configurable (programmable) tap coefficients. Specifically

8. A method of operating a silicon photonic transceiver, comprising: (i) generating a modulated optical signal using a silicon photonic Mach-Zehnder modulator formed on a substrate; (ii) applying a pre-emphasis equalized drive signal to the modulator, the drive signal generated by an equalization circuit co-integrated on the same substrate as the modulator; and (iii) routing the drive signal from the equalization cir

13. The method of claim 8, wherein the equalization circuit and the Mach-Zehnder modulator share common ground planes and power distribution networks formed in the same metallization layers of the substrate. This limitation is definitively not met by Lumos's multi-chip architecture. In Lumos's products, the CMOS driver die and the SiPh modulator die have entirely separate metallization stacks. Each die has its own se

IV. Construction Risk Assessment for Key Disputed Term A. "Pre-emphasis equalization stage electrically co-integrated with the modulator on a common substrate" The construction of this phrase will be the most significant issue at the Markman hearing with respect to the '890 Patent. We set forth below the competing constructions, the relevant intrinsic and extrinsic evidence, and our assessment of the construction ris

V. Prosecution History Estoppel Analysis The doctrine of prosecution history estoppel, as articulated by the Supreme Court in Festo Corp. v. Fenmore & Co., 535 U.S. 722 (2002), provides that when a patent claim is narrowed by amendment during prosecution for a reason related to patentability, there is a presumption that the patentee surrendered the territory between the original claim scope and the amended claim scop

VI. Invalidity Considerations Specific to the '890 Patent A comprehensive validity risk assessment for all four asserted patents is being prepared as a separate consolidated memorandum and is expected to be completed by May 22, 2022. The following discussion addresses invalidity considerations that are specific to the '890 Patent and are relevant to the overall pre-suit assessment. Key Prior Art Reference: Iyer & Pat

Section 112 Risks. In addition to prior art-based invalidity arguments, Lumos may raise challenges under 35 U.S.C. § 112. Lumos may argue that the specification of the '890 Patent does not provide adequate written description support for the full scope of the term "co-integrated," or that the claims are indefinite as to the boundary between what constitutes "co-integrated" on a "common substrate" and what constitutes

VII. Damages Implications If infringement of the '890 Patent can be established — which, as discussed above, requires a favorable claim construction on the "co-integrated" limitation — damages would be calculated under a reasonable royalty theory pursuant to 35 U.S.C. § 284. This section provides a preliminary assessment of the damages implications specific to the '890 Patent. Revenue Base. The combined estimated rev

VIII. Comparison with Other Asserted Patents This Section provides a brief cross-reference to the companion pre-suit infringement analysis memoranda prepared for the other three patents proposed for assertion against Lumos: U.S. Patent No. 10,785,567 (the "'567 Patent"), U.S. Patent No. 10,923,234 (the "'234 Patent"), and U.S. Patent No. 11,045,678 (the "'678 Paten