DCT

3:24-cv-01010

Applied Optoelectronics Inc v. Cambridge Industries USA Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:24-cv-01010, N.D. Cal., 04/25/2024
  • Venue Allegations: Plaintiff alleges venue is proper in the Northern District of California because Defendant maintains a regular and established place of business in Santa Clara, California, and has committed alleged acts of infringement in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s optical transceiver modules infringe eight patents related to the mechanical structure, internal component layout, and optical-electrical interfaces of such devices.
  • Technical Context: The technology at issue involves high-speed pluggable optical transceivers, which are essential components for converting electrical data signals into light for transmission over fiber optic networks and are critical for the operation of data centers, cable television, and telecommunications infrastructure.
  • Key Procedural History: The complaint alleges that Plaintiff sent a notice letter with claim charts to Defendant's CEO on October 20, 2023, identifying alleged infringement of six of the eight asserted patents. This pre-suit notice forms the basis for Plaintiff's allegations of willful infringement for those six patents.

Case Timeline

Date Event
2012-12-10 ’383 Patent Priority Date
2013-10-02 ’826 Patent Priority Date
2015-10-27 ’383 Patent Issue Date
2016-04-25 ’116 Patent Priority Date
2016-05-23 ’301 Patent Priority Date
2016-08-19 ’431 Patent Priority Date
2016-12-20 ’826 Patent Issue Date
2017-07-13 ’432 Patent Priority Date
2018-04-26 ’024 Patent Priority Date
2018-08-07 ’116 Patent Issue Date
2019-01-08 ’431 Patent Issue Date
2019-01-25 ’690 Patent Priority Date
2019-06-04 ’024 Patent Issue Date
2019-08-13 ’301 Patent Issue Date
2019-11-05 ’432 Patent Issue Date
2020-09-29 ’690 Patent Issue Date
2023-10-20 Plaintiff sent notice letter to Defendant
2023-12-04 Defendant’s parent company acknowledged receipt of notice letter
2024-04-25 First Amended Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,523,826 - "Pluggable optical transceiver module"

  • Patent Identification: U.S. Patent No. 9,523,826, "Pluggable optical transceiver module", issued on December 20, 2016.

The Invention Explained

  • Problem Addressed: The patent's background section describes the need for optical transceiver modules to be securely fastened into sockets within electronic communication facilities, while also allowing for easy removal for repair or replacement. It also notes that dust contamination on the transceiver's internal components can damage the module and degrade signal transmission. (’826 Patent, col. 1:20-53).
  • The Patented Solution: The invention is a mechanical design for a pluggable transceiver that features a sliding component with two extending arms. This component slides along slots on the main body of the transceiver. In a "fastening position," parts on the arms engage with latches in the socket. Pulling a handle moves the component to a "releasing position," where inclined surfaces on the arms actively press against the socket latches, spreading them apart to disengage the module. The design of the sliding slots does not penetrate the module's inner surface, which helps protect the internal electronics from dust. (’826 Patent, Abstract; col. 3:19-24; col. 4:54-62).
  • Technical Importance: This design approach seeks to provide a more convenient and reliable connection and disconnection mechanism for pluggable transceivers, which are fundamental to the maintenance and flexibility of high-speed communication networks. (’826 Patent, col. 1:49-53).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 7. (Compl. ¶34).
  • Independent Claim 1 includes the following essential elements:
    • A main body with two side surfaces and two corresponding sliding slots.
    • At least one limiting space formed on the main body.
    • A sliding component with a linkage arm and two extending arms that are slidably disposed on the sliding slots.
    • Each extending arm has a second fastening part (for engaging a socket) and a limited part (to move within the limiting space).
    • An elastic component located within the limiting space and confined by the main body and the sliding component.
  • Independent Claim 7 recites a similar module with a main body comprising a head part and an inserted part, a sliding component, and an elastic component. (Compl. ¶35, Ex. I at 8-10).

U.S. Patent No. 10,466,432 - "High speed optical transceiver module"

  • Patent Identification: U.S. Patent No. 10,466,432, "High speed optical transceiver module", issued on November 5, 2019.

The Invention Explained

  • Problem Addressed: The patent background identifies challenges in manufacturing high-speed optical transceivers, specifically the unreliability and complexity of directly soldering the optical engine (the core optical components) to the main printed circuit board assembly (PCBA). This process can degrade signal transmission and lower manufacturing yields. (’432 Patent, col. 1:20-34).
  • The Patented Solution: The patent proposes a modular architecture where a "passive optical element" (containing components like ferrules and a fiber array) is a separate module that is inserted into corresponding fiber interfaces on the PCBA component. This plug-in connection replaces the direct soldering process, allowing the PCBA and the passive optical element to be manufactured and tested separately before final assembly. This approach is intended to improve production efficiency, yield, and functional flexibility. (’432 Patent, Abstract; col. 2:54-col. 3:2).
  • Technical Importance: This modular design addresses key manufacturing bottlenecks for high-speed transceivers by decoupling the production of the primary electronics from the optical sub-assembly, which may increase manufacturing yield and allow for greater product variation. (’432 Patent, col. 2:54-61).

Key Claims at a Glance

  • The complaint asserts independent claim 1. (Compl. ¶43).
  • Independent Claim 1 includes the following essential elements:
    • A printed circuit board assembly (PCBA) component having a receiver and a transmitter.
    • A passive optical element.
    • The receiver includes an amplifier chip and a photodiode array.
    • The transmitter includes a laser driving chip, a base, and a plurality of lasers.
    • The PCBA has a plurality of fiber interfaces arranged on output light paths corresponding to the lasers.
    • The passive optical element comprises ferrules (corresponding to the fiber interfaces) and a fiber array (for emitting light onto the photodiode array).
    • The ferrules are inserted into the fiber interfaces.

Multi-Patent Capsules

  • U.S. Patent No. 9,170,383: “Multi-channel optical transceiver module including dual fiber type direct link adapter for optically coupling optical subassemblies in the transceiver module,” issued October 27, 2015.

    • Technology Synopsis: This patent describes a multi-channel optical transceiver where a "dual fiber type direct link adapter" is located inside the transceiver housing. This adapter serves as an interface, directly linking the internal transmitter (TOSA) and receiver (ROSA) subassemblies with external, pluggable fiber optic connectors (e.g., LC connectors). (’383 Patent, Abstract).
    • Asserted Claims: Independent claim 1 is asserted. (Compl. ¶52).
    • Accused Features: The complaint alleges that the internal structure of the Accused Products, which connects the internal optical components to the external ports, infringes this patent. (Compl. ¶53, Ex. K).

  • U.S. Patent No. 10,379,301: “Multi-channel parallel optical receiving device,” issued August 13, 2019.

    • Technology Synopsis: This patent discloses an optical receiving device where optoelectronic diodes and a light-receiving chip are mounted on the same top surface of a carrier. An arrayed waveguide grating (AWG) is also mounted on the carrier and is designed with a top surface at a predetermined angle to reflect and direct separate light channels onto the photosensitive surfaces of the diodes. (’301 Patent, Abstract).
    • Asserted Claims: Independent claims 1 and 7 are asserted. (Compl. ¶62).
    • Accused Features: The complaint accuses the receiver subassembly within the Accused Products, particularly the arrangement of the carrier, light receiving chip, diodes, and AWG, of infringement. (Compl. ¶63, Ex. L-N).

  • U.S. Patent No. 10,788,690: “Optical Isolator Array For Use In An Optical Subassembly Module,” issued September 29, 2020.

    • Technology Synopsis: This patent describes an array of optical isolators mounted on a single magnetic base. This integrated array is designed for use within an optical subassembly, allowing multiple optical channels to be isolated from back-reflections using a single, modular component. The use of a magnetic base and adhesive facilitates precise alignment and secure mounting of the isolators. (’690 Patent, Abstract).
    • Asserted Claims: Independent claim 1 is asserted. (Compl. ¶72).
    • Accused Features: The complaint targets the optical isolator array used within the transmitter optical subassembly (TOSA) of certain Accused Products. (Compl. ¶73, Ex. O).

  • U.S. Patent No. 10,313,024: “Transmitter Optical Subassembly With Trace Routing To Provide Electrical Isolation Between Power And RF Traces,” issued June 4, 2019.

    • Technology Synopsis: The technology relates to a transmitter optical subassembly (TOSA) that provides electrical isolation between high-frequency radio frequency (RF) signal traces and power traces (e.g., DC traces). The design routes these different types of electrical traces on opposite sides of a substrate or in an opposing arrangement to reduce electrical interference, which is critical for maintaining signal integrity in high-speed devices. (’024 Patent, Abstract; col. 1:11-15).
    • Asserted Claims: Independent claim 1 is asserted. (Compl. ¶82).
    • Accused Features: The complaint alleges that the layout of the printed circuit board (PCB) and substrate within the TOSA of the Accused Products, which separates power and RF signal traces, infringes the patent. (Compl. ¶83, Ex. P).

  • U.S. Patent No. 10,175,431: “Optical transceiver with a multiplexing device positioned off-center within a transceiver housing to reduce fiber bending loss,” issued January 8, 2019.

    • Technology Synopsis: This patent addresses the problem of fiber bending loss within compact transceiver housings. The solution involves positioning a demultiplexer (like an AWG) off-center from the main longitudinal axis of the housing. This lateral offset provides more physical space to route an internal optical fiber between the external connector and the AWG, allowing for a larger bend radius and reducing signal loss. (’431 Patent, Abstract).
    • Asserted Claims: Independent claims 1 and 16 are asserted. (Compl. ¶92).
    • Accused Features: The infringement allegation focuses on the internal layout of the Accused Products, specifically the off-center placement of the AWG device relative to the housing's centerline. (Compl. ¶93, Ex. Q).

  • U.S. Patent No. 10,042,116: “Techniques for direct optical coupling of photodetectors to optical demultiplexer outputs and an optical transceiver using the same,” issued August 7, 2018.

    • Technology Synopsis: The invention describes a method for directly coupling photodetectors to the output of an optical demultiplexer (an AWG) without an intermediate fiber array. The AWG chip includes a tapered region with an angled surface that reflects the demultiplexed light channels directly towards an output interface, where detector devices can be placed for direct coupling. This design aims to reduce the component count and optical losses associated with using a fiber array. (’116 Patent, Abstract).
    • Asserted Claims: Independent claim 1 is asserted. (Compl. ¶102).
    • Accused Features: The complaint targets the receiver optical subassembly (ROSA) in the Accused Products, alleging that its use of an AWG chip with a tapered, reflective output for direct coupling to photodetectors infringes the patent. (Compl. ¶103, Ex. R-T).

III. The Accused Instrumentality

Product Identification

The accused products are a line of optical transceiver modules, including the CIG 100G QSFP CWDM4 (Versions 1 and 2), CIG 100G LR4 Module, CIG 400G QSFP-DD DR4 Module, CIG 400G QSFP-DD FR4 Module, and CIG 100G QSFP28 PSM4. (Compl. ¶21).

Functionality and Market Context

The Accused Products are pluggable modules that convert electrical data to optical signals for transmission over fiber optic networks and vice-versa. (Compl. ¶19). They are marketed for use in high-speed networking applications such as data centers. (Compl. ¶12, ¶19). The complaint provides an annotated photograph of the CIG 100G QSFP28 PSM4, identifying its external "main body," "side surfaces," and "sliding component" as relevant to the infringement allegations. (Compl. Ex. I at 6, Fig. 1). Another photograph of the same product disassembled shows the internal "PCBA component" and "passive optical element." (Compl. Ex. J at 2, Fig. 1).

IV. Analysis of Infringement Allegations

’826 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A pluggable optical transceiver module... The accused CIG 100G QSFP28 PSM4 is a pluggable optical transceiver module. ¶35 col. 5:18
a main body having two side surfaces that are opposite to each other and two sliding slots located at the two side surfaces, respectively, The accused product's main body has two opposite side surfaces with sliding slots located on each. ¶35 col. 3:1-6
a sliding component comprising a linkage arm and two extending arms... The accused product has a sliding component that includes a linkage arm and two extending arms. ¶35 col. 3:25-28
...the two extending arms are slidably disposed on the two sliding slots to have a fastening position and a releasing position, The extending arms of the sliding component are disposed in the sliding slots of the main body and can move between fastening and releasing positions. ¶35 col. 3:49-54
wherein each extending arm has a limited part configured to move in the at least one limiting space; Each extending arm of the sliding component has a limited part that moves within a limiting space on the main body. ¶35 col. 3:33-35; col. 3:43-46
and an elastic component, wherein the main body has a first limiting surface and a second limiting surface forming the limiting space... and the elastic component is located in the limiting space... and is covered by the extending arm such that the elastic component is confined by the main body and the sliding component. The accused product contains an elastic component located within the limiting space, between limiting surfaces, and allegedly confined by the main body and sliding component. ¶35 col. 4:11-19; col. 5:46-54
  • Identified Points of Contention:
    • Scope Questions: The complaint alleges, "on information and belief," that the second fastening parts press the socket's fastening parts apart. (Compl. Ex. I at 7). A potential dispute is whether the accused device's release mechanism functions by this specific "pressing" action, as required by the claim, or through a different mechanical interaction.
    • Technical Questions: What is the precise nature of the confinement of the "elastic component" in the accused product? The claim requires the component to be "covered by the extending arm such that the elastic component is confined by the main body and the sliding component," which suggests a specific structural arrangement that will require factual evidence to verify.

’432 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A high-speed optical transceiver module, comprising: The accused CIG 100G QSFP28 PSM4 is identified as a high-speed optical transceiver module. ¶44 col. 3:9
a printed circuit board assembly (PCBA) component having a receiver and a transmitter; and a passive optical element, The accused product contains a PCBA component with a receiver and transmitter, and a separate passive optical element. ¶44 col. 3:10-12
wherein the receiver comprises an amplifier chip and a photodiode array connected to pins of the amplifier chip; The receiver on the PCBA includes an amplifier chip and a photodiode array, with the complaint alleging connection via wire bonds. ¶44 col. 3:14-16
the transmitter comprises a laser driving chip and a base; the base comprises a plurality of lasers arranged side by side; The transmitter on the PCBA includes a laser driving chip, a base, and a plurality of lasers arranged side-by-side. ¶44 col. 3:16-19
the passive optical element comprises ferrules corresponding to the fiber interfaces and a fiber array for emitting light on the photodiode array of the receiver; and the ferrules are inserted into the plurality of fiber interfaces in one-to-one correspondence. The passive optical element includes ferrules that are inserted into fiber interfaces on the PCBA and a fiber array allegedly positioned to emit light onto the photodiode array. ¶44 col. 3:20-24; col. 4:45-51
  • Identified Points of Contention:
    • Scope Questions: Does the accused product's assembly of fibers, ferrules, and a connector constitute a "passive optical element" as that term is understood in the patent, which emphasizes a modular component that can be manufactured separately from the PCBA?
    • Technical Questions: What evidence does the complaint provide that the "ferrules are inserted into the plurality of fiber interfaces" in the specific manner claimed? Verifying this physical and optical connection, as shown in annotated photographs (Compl. Ex. J at 3, Fig. 2), will be a key factual question.

V. Key Claim Terms for Construction

For the ’826 Patent

  • The Term: "an elastic component... confined by the main body and the sliding component"
  • Context and Importance: This term is central to the claimed invention's mechanical structure. The manner in which the elastic component is positioned and "confined" distinguishes the patented design. Practitioners may focus on this term because infringement will depend on whether the accused product's spring mechanism is constrained by both the main body and sliding component in the specific way recited.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification generally describes that "Two elastic components 400 are located at the two limiting spaces 150, respectively." (’826 Patent, col. 4:11-12).
    • Evidence for a Narrower Interpretation: The claim language itself provides significant detail: "the elastic component is located in the limiting space and between the first limiting surface and the limited part and is covered by the extending arm such that the elastic component is confined by the main body and the sliding component." (’826 Patent, col. 5:46-54). This detailed recitation may be argued to strictly define the term's scope.

For the ’432 Patent

  • The Term: "passive optical element"
  • Context and Importance: This term defines the modular component that is the core of the invention, distinguishing it from prior art integrated optical engines. The case may turn on whether the accused product's optical front-end assembly, which is separable from the PCBA, meets the definition of this term.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification provides examples, stating that "the passive optical element is a multi push on (MPO) connector" which may include ferrules and a fiber array. (’432 Patent, col. 2:5-7).
    • Evidence for a Narrower Interpretation: The patent's summary emphasizes the modularity, stating "The PCBA component and the passive optical element can be manufactured separately, and assembled later." (’432 Patent, col. 2:59-61). A defendant may argue that this implies a self-contained, pre-assembled module, and not just a collection of components that are assembled together with the PCBA.

VI. Other Allegations

  • Indirect Infringement: The complaint does not provide sufficient detail for analysis of indirect infringement.
  • Willful Infringement: The complaint alleges willful infringement for six of the eight patents (’301, ’383, ’116, ’431, ’690, and ’024) based on alleged pre-suit knowledge stemming from a notice letter sent on October 20, 2023. (Compl. ¶¶ 24-25, 55, 65, 75, 85, 95, 105). For the remaining two patents (’826 and ’432), the basis for knowledge is alleged to be post-suit, arising "since at least, and through, the filing of the original complaint in this matter." (Compl. ¶37, ¶46).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A central issue will be one of structural and functional correspondence: does the mechanical latching and release mechanism of the accused transceivers operate by "pressing" the socket latches apart via an inclined surface, and does it contain an "elastic component" that is "confined" in the precise manner required by the '826 patent claims?
  • A key question will be one of definitional scope: can the modular architecture of the accused products, where an optical front-end connects to a main PCBA, be categorized as comprising a "passive optical element" that is "inserted into... fiber interfaces" as defined by the '432 patent, particularly in light of the patent's emphasis on separate manufacturability?
  • A significant evidentiary question will concern willfulness: for six of the asserted patents, the case will examine whether the pre-suit notice letter provided Defendant with knowledge of infringement sufficient to support a finding of willful conduct from October 20, 2023, onward.