Contract analysis

I. INTRODUCTION Plaintiff Optiwave Semiconductor Corp. ("OWS") hereby submits its Responsive Claim Construction Contentions pursuant to Patent Local Rule 4-2 of the Northern District of California. These contentions respond to the Preliminary Claim Construction Contentions served by Defendant Lumos Photonics, Inc. ("Lumos") on September 12, 2022, in accordance with Patent Local Rule 4-1. OWS's Responsive Contentions

II. AGREED-UPON CONSTRUCTIONS Pursuant to Patent Local Rule 4-2, OWS identifies below the claim terms from either party's Preliminary Claim Construction Contentions on which the parties have reached agreement, as well as those terms that OWS agrees require no judicial construction. A. Terms on Which the Parties Have Reached Agreement Following the exchange of Preliminary Claim Construction Contentions and subsequent

III. DISPUTED CLAIM TERMS — U.S. PATENT NO. 10,234,567 ("THE '567 PATENT") The '567 Patent is directed to a silicon photonic waveguide structure that employs adiabatic mode transitions to achieve efficient optical coupling between waveguide layers of different materials and geometries in a photonic integrated circuit. The patent claims priority to a provisional application filed on March 14, 2017, and was issued on M

1. Lumos's Proposed Construction In its Preliminary Claim Construction Contentions, Lumos proposed the following construction for the term "adiabatically coupled" as it appears in Claim 1 of the '567 Patent: Lumos's Proposed Construction: "coupled through a gradual, continuous taper that prevents excitation of higher-order modes throughout the entire transition region." OWS objects to Lumos's proposed construction on

2. OWS's Responsive Position OWS maintains its proposed construction as set forth in its Preliminary Claim Construction Contentions served on August 29, 2022: OWS's Proposed Construction: "coupled such that optical mode transitions occur without significant power loss." This construction faithfully reflects the plain and ordinary meaning of "adiabatically coupled" as understood by a person of ordinary skill in the ar

3. Intrinsic Evidence Support OWS's proposed construction is firmly grounded in the intrinsic evidence of the '567 Patent. Specification. The specification of the '567 Patent describes the adiabatic coupling as achieving "low-loss optical mode transition" between the silicon waveguide layer and the silicon nitride waveguide layer. See '567 Patent, col. 3, ll. 15–28 ("The tapered silicon waveguide is adiabatically cou

4. Rebuttal of Lumos's Narrowing Arguments Lumos's proposed construction suffers from three critical defects, each of which is addressed below. First, Lumos's insertion of "continuous" into the construction improperly imports a structural limitation from a single preferred embodiment into the claim term. While the specification discloses "continuous" tapers as one embodiment of the invention, it also discloses multi-

5. Extrinsic Evidence In further support of its proposed construction, OWS will rely on the following extrinsic evidence: • Technical Dictionaries and Treatises. Standard references in integrated photonics define "adiabatic" in the context of optical waveguide transitions as pertaining to gradual transitions that preserve the fundamental optical mode character — that is, transitions in which the propagating mode rema

1. Lumos's Proposed Construction In its Preliminary Contentions, Lumos proposed the following construction for this term: Lumos's Proposed Construction: "a silicon waveguide having a gradually narrowing cross-section terminating at a single point where the width, measured by scanning electron microscopy or equivalent metrology, is less than 200 nanometers."

2. OWS's Responsive Position OWS contends that this term requires no construction beyond its plain and ordinary meaning, which is readily understood by a POSITA to refer to a silicon waveguide that tapers to a tip width of less than 200 nanometers. The claim language is clear and self-defining: the waveguide is "tapered," the material is "silicon," and the tip width dimensional limitation is expressly specified. Lumo

1. Lumos's Proposed Construction In its Preliminary Contentions, Lumos proposed the following construction for the term "laterally offset" as it appears in dependent Claim 7 of the '567 Patent: Lumos's Proposed Construction: "displaced in the horizontal plane of the waveguide by a fixed distance from the centerline of the adjacent waveguide layer, as measured perpendicular to the direction of light propagation."

2. OWS's Responsive Position OWS contends that "laterally offset" should be construed as: OWS's Proposed Construction: "displaced to the side relative to the adjacent waveguide." OWS's construction captures the straightforward meaning of "laterally offset" without importing unnecessary specificity. While a POSITA would understand that a lateral offset occurs in a direction generally perpendicular to the direction of

3. Intrinsic and Extrinsic Evidence OWS relies on the specification passages cited above and the prosecution history of the '567 Patent, which contains no narrowing discussion of the term "laterally offset." OWS further relies on Dr. Whitfield's anticipated testimony regarding the understanding of a POSITA. D. "evanescent field overlap region" (Claim 12)

1. Lumos's Proposed Construction Lumos proposed the following construction: Lumos's Proposed Construction: "a physical region where the evanescent optical field tails from two distinct waveguide structures overlap in space, enabling power transfer exclusively through evanescent coupling."

2. OWS's Responsive Position OWS proposes the following construction: OWS's Proposed Construction: "a region where the evanescent fields of two waveguides overlap." Lumos's insertion of "exclusively through evanescent coupling" improperly limits the power transfer mechanism. In practice, in an adiabatic coupler operating within an evanescent field overlap region, power transfer occurs through a combination of evanesc

3. Intrinsic and Extrinsic Evidence OWS relies on the specification at column 7, lines 15–35, which describes the evanescent field overlap region in the context of the adiabatic coupling mechanism without limiting the power transfer to exclusively evanescent coupling. OWS further relies on Dr. Whitfield's anticipated testimony and standard photonics references describing evanescent field overlap in coupled waveguide

IV. DISPUTED CLAIM TERMS — U.S. PATENT NO. 10,891,234 ("THE '234 PATENT") The '234 Patent is directed to a high-responsivity germanium-on-silicon photodetector incorporating a graded buffer layer architecture to manage lattice mismatch between the silicon substrate and the germanium absorber layer, thereby achieving enhanced photodetector performance. The patent claims priority to an application filed on September 8,

1. Lumos's Proposed Construction In its Preliminary Claim Construction Contentions, Lumos proposed the following construction: Lumos's Proposed Construction: "a buffer layer in which the germanium atomic fraction increases monotonically and without step changes from the silicon substrate interface to the absorber layer." OWS objects to Lumos's proposed construction on the grounds that it improperly adds three distinc

2. OWS's Responsive Position OWS maintains its proposed construction as set forth in its Preliminary Contentions: OWS's Proposed Construction: "a buffer layer in which the germanium concentration changes across the layer thickness." The claim language "continuously varying" is most naturally read in context to describe a germanium concentration that changes — that is, varies — across the thickness of the buffer layer

3. Intrinsic Evidence Support Specification. The specification of the '234 Patent provides direct and compelling support for OWS's proposed construction. The specification discloses embodiments describing both "continuously graded" and "step-graded" buffer layers as implementations of the claimed graded buffer architecture. Specifically, the specification at column 5, lines 40–55, states: "In one embodiment, the grad

4. Rebuttal of Lumos's Narrowing Arguments Preferred Embodiment Importation. Lumos's construction improperly reads the preferred embodiment limitation — a smooth, continuously graded profile — into the claims by treating the smooth gradient description as the exclusive definition of "continuously varying." While the specification discloses a smooth gradient as one embodiment, it expressly discloses step-graded buffer

5. Extrinsic Evidence OWS will rely on the following extrinsic evidence in support of its proposed construction: • Semiconductor Physics References and Textbooks. Standard references in semiconductor device physics and epitaxial growth describe graded buffer layers for germanium-on-silicon integration and treat both continuously graded and step-graded approaches as implementations of graded concentration profiles. Se

1. Lumos's Proposed Construction In its Preliminary Contentions, Lumos identified the preamble phrase "enhanced responsivity" from Claim 1 of the '234 Patent as a term requiring construction and proposed: Lumos's Proposed Construction: "an increase in photodetector responsivity, measured in amperes per watt, of at least 15% relative to a comparable photodetector without a graded buffer layer."

2. OWS's Responsive Position OWS contends, as a threshold matter, that the preamble of Claim 1 is not limiting. The preamble recites: "A photodetector device with enhanced responsivity, comprising:..." The body of the claim fully sets forth the structural elements of the invention, and the preamble phrase "with enhanced responsivity" merely states a purpose or intended result of the claimed structure — it does not pr

1. Lumos's Proposed Construction Lumos proposed: Lumos's Proposed Construction: "a threading dislocation density measured by plan-view transmission electron microscopy (PVTEM) of less than 1×10⁶ per square centimeter."

2. OWS's Responsive Position OWS contends that the numerical limitation "less than 1×10⁶ cm⁻²" is clear on its face. OWS objects to Lumos's importation of a specific measurement methodology (PVTEM) into the construction, for the same reasons discussed in Section III.B above with respect to the tip width measurement methodology. The claim language specifies the metric ("defect density") and the threshold ("less than 1

V. DISPUTED CLAIM TERMS — U.S. PATENT NO. 11,045,678 ("THE '678 PATENT") The '678 Patent is directed to a monolithically integrated multi-channel optical transceiver incorporating wavelength-division multiplexing (WDM) on a single silicon die. The patent claims priority to an application filed on June 22, 2018, and was issued on June 29, 2021, after prosecution that included three office action rejections and an amen

1. Lumos's Proposed Construction In its Preliminary Claim Construction Contentions, Lumos proposed the following construction: Lumos's Proposed Construction: "a WDM component formed during front-end-of-line processing within the same silicon substrate, excluding hybrid integration, flip-chip bonding, or any heterogeneous integration technique." OWS objects to this construction on the grounds that it improperly import

2. OWS's Responsive Position OWS maintains its proposed construction: OWS's Proposed Construction: "a WDM component fabricated as part of the same semiconductor fabrication process on a single die." The term "monolithically formed" is a well-understood term of art in semiconductor manufacturing. A POSITA would understand "monolithically formed" to mean fabricated on or within the same substrate using standard semicon

3. Intrinsic Evidence Support Specification. The specification of the '678 Patent describes the WDM element as being "monolithically formed on a single silicon die" and provides embodiments in which the WDM component — an arrayed waveguide grating (AWG) or Echelle grating — is fabricated using standard CMOS-compatible processing steps. See '678 Patent, col. 4, ll. 20–45. The specification emphasizes the benefits of m

4. Rebuttal of Lumos's Narrowing Arguments Overbroad Categorical Exclusions. Lumos's categorical exclusion of "hybrid integration, flip-chip bonding, or any heterogeneous integration technique" sweeps far more broadly than warranted by the prosecution history. The applicant's remarks during prosecution distinguished specific prior art references that involved fabrication of the WDM component on a separate substrate (

5. Extrinsic Evidence OWS will rely on the following extrinsic evidence: • Semiconductor Industry Usage. The terms "monolithic integration" and "monolithically formed" have well-established meanings in the semiconductor and photonics industry. Industry standards bodies, including IEEE and SEMI, use "monolithic" to refer to fabrication on a single substrate, without limiting the term to a specific subset of process st

1. Lumos's Proposed Construction Lumos proposed: Lumos's Proposed Construction: "a feedback control circuit that measures the wavelength of each WDM channel and adjusts a local heater to stabilize the channel wavelength to within ±0.1 nm of the target wavelength."

2. OWS's Responsive Position OWS proposes: OWS's Proposed Construction: "a circuit that adjusts the operating wavelength of the WDM element to compensate for temperature variations." Lumos's construction improperly imports the specific performance metric "±0.1 nm" from a single example in the specification and restricts the stabilization mechanism to "a local heater," excluding other thermal management approaches (e.

VI. DISPUTED CLAIM TERMS — U.S. PATENT NO. 11,312,890 ("THE '890 PATENT") The '890 Patent is directed to a co-integrated pre-emphasis equalization circuit for high-speed silicon photonic modulators, aimed at improving signal integrity and bandwidth by placing the equalization circuitry on the same substrate as the modulator. The patent claims priority to an application filed on November 15, 2018, and was issued on Ap

1. Lumos's Proposed Construction In its Preliminary Claim Construction Contentions, Lumos proposed the following construction: Lumos's Proposed Construction: "an equalization circuit fabricated in the same semiconductor process as the modulator, sharing the same doping profiles and process layers, and electrically connected without bond wires, interposers, or package-level routing." OWS objects to this construction o

2. OWS's Responsive Position OWS maintains its proposed construction: OWS's Proposed Construction: "an equalization circuit located on the same substrate as the modulator." The term "co-integrated" in the context of silicon photonic modulators and their driver circuits is understood by a POSITA to mean that the equalization circuit and the modulator share a common substrate — that is, they are fabricated on the same

3. Intrinsic Evidence Support Specification. The specification of the '890 Patent describes the driver circuit and modulator as being on a "common substrate" and discusses the benefits of this co-integration arrangement: "By co-integrating the pre-emphasis equalization stage with the Mach-Zehnder modulator on a common silicon substrate, the present invention achieves a significant reduction in parasitic capacitance a

4. Rebuttal of Lumos's Narrowing Arguments "Sharing the Same Doping Profiles and Process Layers" — Technically Nonsensical. Lumos's requirement that the equalization circuit share "the same doping profiles and process layers" as the modulator is technically nonsensical, and a POSITA would immediately recognize it as such. In any integrated circuit — and particularly in a silicon photonic integrated circuit — differen