Cambridge Industries USA Inc v. Applied Optoelectronics Inc

1. Case Identification

• Case #: IPR2025-00435
• Patent #: 10,042,116
• Filed: January 17, 2025
• Petitioner(s): Cambridge Industries USA Inc.
• Patent Owner(s): Applied Optoelectronics, Inc.
• Challenged Claims: 1-19

2. Patent Overview

• Title: Optical Transceiver Module with Arrayed Waveguide Grating
• Brief Description: The ’116 patent is directed to an optical transceiver module that includes an arrayed waveguide grating (AWG) chip. The technology involves using a planar lightwave circuit (PLC) on the AWG chip to demultiplex a multi-wavelength optical signal, with a tapered region at one end of the chip reflecting the separated wavelengths towards an output interface located on the same side as the substrate.

3. Grounds for Unpatentability

Ground 1: Anticipation over Soldano - Claims 1-11 are anticipated by Soldano.

• Prior Art Relied Upon: Soldano (Patent 9,768,901).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Soldano discloses every element of claims 1-11. Soldano teaches a photonics module with an AWG demultiplexer on a PLC, an input for receiving a multi-wavelength signal, and output waveguides. Critically, Petitioner asserted that Soldano's use of a polished angled end face to redirect demultiplexed wavelengths to an array of photodetectors meets the limitation of a "tapered region" that reflects light towards an "exposed output interface region" which emits light on the same side as the substrate.

Ground 2: Anticipation over Shen - Claims 1-11 are anticipated by Shen.

• Prior Art Relied Upon: Shen (Application # 2016/0349451).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Shen, which discloses an optical receiver module with an AWG chip mounted on a substrate, anticipates claims 1-11. Shen describes demultiplexing a multi-wavelength signal and redirecting the individual channel wavelengths to photodetectors using an angled surface end. Petitioner mapped Shen’s angled reflector to the claimed "tapered region," its photodetector array to the "output interface region," and its overall structure to the remaining limitations of independent claim 1 and its dependents.

Ground 3: Obviousness over Kanazawa and Sasaki - Claims 1-11 are obvious over Kanazawa in view of Sasaki.

• Prior Art Relied Upon: Kanazawa (JP 2012-034314A) and Sasaki (JP 2003-215371A).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner asserted that Kanazawa teaches a multi-channel optical receiver using a PLC with a demultiplexer and discrete 45-degree mirrors to redirect light to photodetectors. Sasaki teaches a PLC with a continuous angled end face that redirects light orthogonally from waveguides to a photodetector. Petitioner argued it would have been obvious to replace Kanazawa's embedded mirrors with Sasaki's simpler, continuous angled end to achieve the structure of claim 1.
  • Motivation to Combine: A POSITA would combine Kanazawa and Sasaki to increase the signal density and compactness of the photonics module. Specifically, substituting Sasaki’s integrated angled end for Kanazawa's discrete mirrors would simplify manufacturing, reduce component count, and improve alignment accuracy.
  • Expectation of Success: Because both references are in the field of optical communications and address similar challenges of component integration and miniaturization, a POSITA would have had a reasonable expectation of success in combining their teachings.

• Additional Grounds: Petitioner asserted additional obviousness challenges for claims 12-19 based on combinations of Soldano, Shen, Kanazawa, and Sasaki, primarily adding Lurie (Patent 5,351,327) or Tomita (Patent 4,978,193) to teach the well-known concept of using angled surfaces at optical input connections to reduce back-reflections.

4. Key Claim Construction Positions

• Petitioner argued that the terms "substrate" and "disposed on the substrate" in claim 1 should be construed narrowly based on amendments made during prosecution to distinguish prior art. This construction would limit the "substrate" to the silicon or silicon-based layer upon which the PLC is directly deposited.
• However, for the purposes of its unpatentability analysis in the inter partes review (IPR), Petitioner adopted the Patent Owner's broader, plain and ordinary meaning of "substrate" as "a supporting structure for an AWG device." Petitioner contended that the claims are unpatentable even under this broader construction, which should apply equally to infringement and validity.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under 35 U.S.C. §325(d), stating that the asserted prior art and combinations were not presented to or considered by the examiner during the original prosecution of the ’116 patent.
• Petitioner also argued against discretionary denial under Fintiv. It asserted that the parallel district court case is in a very early stage, with claim construction not scheduled until April 2025 and a trial date set for June 2026, well after the IPR's statutory deadline for a final written decision. Furthermore, Petitioner stipulated that if the IPR is instituted, it will not pursue invalidity in the district court using the specific prior art combinations presented in the petition.

6. Relief Requested

• Petitioner requests institution of an IPR and cancellation of claims 1-19 of Patent 10,042,116 as unpatentable.