PTAB

IPR2025-01566

Accelight Technologies Inc v. Applied Optoelectronics Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Arrayed Waveguide Grating Chip and Optical Transceiver Module
  • Brief Description: The ’116 patent relates to an Arrayed Waveguide Grating (AWG) chip and an optical transceiver module using it. The technology focuses on a direct optical coupling technique where a tapered region with an angled reflective surface at one end of the AWG chip redirects demultiplexed light to an array of photodetectors, aiming to reduce insertion loss compared to systems using fibers or separate waveguides.

3. Grounds for Unpatentability

Ground 1: Obviousness over Lee and Kim - Claims 1-4, 10-11 are obvious over Lee in view of Kim.

  • Prior Art Relied Upon: Lee (Application # 2014/0183344) and Kim (Application # 2014/0169389).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Lee disclosed the core inventive concept: a hybrid optical module where a planar lightwave circuit (PLC) has an inclined surface (desirably 45 degrees) to reflect light orthogonally onto a photodiode array, achieving direct coupling. However, Lee did not explicitly detail the AWG structure or an input connector. Petitioner asserted that Kim supplied these missing elements, disclosing an optical receiver with a complete AWG demultiplexer, an optical input connector receptacle, and a similar 45-degree angled mirror for reflecting demultiplexed signals to a photodetector array.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Lee and Kim because both references address the same problem of efficiently coupling a demultiplexer to a photodetector array in optical communication modules. Petitioner contended that a POSITA would look to Kim to provide the specific AWG structure and necessary input connector that are described generally or are absent in Lee, thereby arriving at the claimed invention.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because combining Kim’s conventional AWG and input connector with Lee’s direct coupling module involved applying known components for their intended functions, leading to the predictable result of an efficient AWG chip.

Ground 2: Obviousness over Bernasconi and Soldano - Claims 1-4, 10-11 are obvious over Bernasconi in view of Soldano.

  • Prior Art Relied Upon: Bernasconi (a 2012 conference paper) and Soldano (Patent 9,768,901).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued Bernasconi disclosed a Receiver Optical Sub-Assembly (ROSA) with a silica PLC-based AWG demultiplexer that uses an angled facet to redirect demultiplexed light onto a photodetector array, achieving high coupling without intermediate lenses. Bernasconi, however, used "free-space collimating optics" for input and did not explicitly show output waveguides. Petitioner asserted that Soldano taught the use of a fiber-coupled input receptacle and distinct output waveguides for an AWG, which are common and more practical implementations.
    • Motivation to Combine: A POSITA would have been motivated to replace Bernasconi’s less robust free-space input optics with Soldano’s more reliable fiber-based optical coupling receptacle to reduce signal loss from misalignment and vibration. Similarly, a POSITA would incorporate Soldano’s explicit output waveguides into Bernasconi’s design, as this is a standard method for routing demultiplexed channels in AWGs to prevent crosstalk.
    • Expectation of Success: The combination was argued to be a predictable integration of established technologies. Replacing a free-space input with a standard fiber connector and adding conventional output waveguides to an AWG design were considered routine design choices for a POSITA.

  • Additional Grounds: Petitioner asserted additional obviousness challenges for claims 12-13 and 15-16 (Grounds 2 and 4). These grounds built upon the core combinations of Lee/Kim and Bernasconi/Soldano by adding Ho (Application # 2014/0341578) to teach a complete optical transceiver module context (including a TOSA and ROSA) and Yoshikawa (Application # 2005/0286839) to explicitly teach using an angled surface at the input receptacle to reduce back reflections.

4. Key Claim Construction Positions

  • Petitioner argued for construing the term "substrate" as "a supporting base that is part of the AWG chip and on which the planar lightwave circuit (PLC) is mounted."
  • This construction was presented as necessary to resolve a dispute from parallel district court litigation, where the Patent Owner allegedly took the position that the substrate could be a separate component external to the AWG chip. Petitioner contended its proposed construction is consistent with the patent's specification and claims.

5. Arguments Regarding Discretionary Denial

  • To preempt a potential discretionary denial under Fintiv, Petitioner provided a stipulation.
  • Petitioner stipulated that if the Board institutes an inter partes review (IPR), it will not pursue in the parallel district court litigation (i) the specific grounds raised in the petition, or (ii) any other grounds based on patents or printed publications that reasonably could have been raised in the petition.

6. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-4, 10-13, and 15-16 of the ’116 patent as unpatentable.