DCT

5:24-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, where it allegedly designs, sells, and offers for sale the accused products.
  • Core Dispute: Plaintiff alleges that Defendant’s high-speed optical transceiver modules infringe eight U.S. patents related to the mechanical design, modular assembly, and internal components of such devices.
  • Technical Context: The technology at issue involves high-speed pluggable optical transceivers, which are essential components for converting electrical data into light for transmission over fiber-optic networks in data centers, telecommunications, and cable television broadband systems.
  • Key Procedural History: The complaint alleges that Plaintiff sent a notice letter on October 20, 2023, to the CEO of Defendant and its Chinese parent corporation, identifying six of the eight now-asserted patents and providing exemplary claim charts. The complaint alleges that the Chinese parent corporation acknowledged receipt of this letter on December 4, 2023. These allegations form the basis for claims of willful infringement for those six patents.

Case Timeline

Date Event
2012-12-10 U.S. Patent No. 9,170,383 Priority Date
2013-10-02 U.S. Patent No. 9,523,826 Priority Date
2015-10-27 U.S. Patent No. 9,170,383 Issued
2016-04-25 U.S. Patent No. 10,042,116 Priority Date
2016-05-23 U.S. Patent No. 10,379,301 Priority Date
2016-08-19 U.S. Patent No. 10,175,431 Priority Date
2016-12-20 U.S. Patent No. 9,523,826 Issued
2017-07-13 U.S. Patent No. 10,466,432 Priority Date
2018-04-26 U.S. Patent No. 10,313,024 Priority Date
2018-08-07 U.S. Patent No. 10,042,116 Issued
2019-01-08 U.S. Patent No. 10,175,431 Issued
2019-01-25 U.S. Patent No. 10,788,690 Priority Date
2019-06-04 U.S. Patent No. 10,313,024 Issued
2019-08-13 U.S. Patent No. 10,379,301 Issued
2019-11-05 U.S. Patent No. 10,466,432 Issued
2020-09-29 U.S. Patent No. 10,788,690 Issued
2023-10-20 Plaintiff sent pre-suit notice letter to Defendant
2023-12-04 Defendant’s parent corporation acknowledged receipt of notice
2024-04-25 Complaint Filed

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 December 20, 2016.

The Invention Explained

  • Problem Addressed: The patent background describes the need for a reliable mechanism to fasten pluggable optical transceivers into their corresponding sockets in high-speed communication equipment. It notes that this mechanism must also allow for easy release and disconnection. A secondary problem addressed is the potential for dust to fall into and damage the transceiver's internal components when fiber optic cables are connected or removed (Compl. Ex. A, p. 32, col. 1:19-54).
  • The Patented Solution: The invention is a mechanical design for a pluggable transceiver that includes a main body and a sliding component with extending arms and a pull handle. The sliding component moves relative to the main body between a "fastening position" and a "releasing position." When the module is inserted, parts on the sliding component engage with fasteners in the socket to lock it in place. Pulling the handle moves the sliding component, causing its specially shaped fastening surfaces to press against the socket's fasteners, spreading them apart and releasing the module. The design also specifies that the sliding slots do not penetrate the inner surface of the main body, which helps protect the internal photoelectric components from dust contamination (Compl. Ex. A, p. 32, col. 1:55-2:10; p. 33, col. 3:27-58).
  • Technical Importance: This design provides a convenient, robust, and dust-resistant mechanical interface for high-density pluggable optical modules, which are frequently installed and replaced in data center environments (Compl. Ex. A, p. 32, col. 1:49-54).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 7 (Compl. ¶34).
  • Independent Claim 1 recites a pluggable optical transceiver module comprising:
    • A main body with two opposite side surfaces and two sliding slots on those surfaces.
    • The main body is configured for insertion into a plugging slot.
    • The main body has at least one limiting space.
    • A sliding component with a linkage arm and two extending arms.
    • Each extending arm has a second fastening part and a limited part configured to move in the limiting space.
    • The main body is positioned between the two extending arms, which are slidably disposed on the sliding slots.
    • The mechanism has a fastening position where the module is secured and a releasing position.
    • An elastic component located in the limiting space between a limiting surface and the limited part, and "covered by the extending arm."
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

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 November 5, 2019.

The Invention Explained

  • Problem Addressed: The patent's background section explains that conventional high-speed optical transceivers are often manufactured by directly soldering the optical engine to the printed circuit board assembly (PCBA). This process is described as complicated, unreliable if the solder connection is faulty, and results in a low manufacturing yield rate (Compl. Ex. B, p. 44, col. 1:20-34).
  • The Patented Solution: The invention proposes a modular design where a separate "passive optical element" (which contains components like ferrules and a fiber array) is inserted into fiber interfaces on the PCBA, rather than being directly soldered. This modular approach allows the PCBA and the passive optical element to be manufactured and tested separately before being assembled. This simplifies the manufacturing process, increases production efficiency, and allows for greater design flexibility (Compl. Ex. B, p. 44, col. 1:56-2:5). The relationship is illustrated in the patent's FIG. 3, which shows the PCBA component (1) and the passive optical element (2) prior to assembly.
  • Technical Importance: This modular manufacturing approach addresses key production challenges in the high-volume, high-precision field of optical transceivers by improving yield and enabling more flexible assembly of different product types from common components (Compl. Ex. B, p. 44, col. 2:2-5).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶43).
  • Independent Claim 1 recites a high-speed optical transceiver module comprising:
    • A printed circuit board assembly (PCBA) component having a receiver and a transmitter.
    • A passive optical element.
    • The receiver comprises an amplifier chip and a photodiode array.
    • The transmitter comprises a laser driving chip, a base, and a plurality of lasers.
    • The PCBA has a plurality of fiber interfaces arranged on the output light paths of 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 plurality of fiber interfaces in a one-to-one correspondence.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

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 compact "dual fiber type direct link adapter" housed within a transceiver module. The adapter creates direct optical links between internal transmitter (TOSA) and receiver (ROSA) subassemblies while also providing a pluggable external interface for fiber optic connectors, accommodating these components within a small form factor (Compl. Ex. C, p. 55, col. 1:9-62).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶52).
    • Accused Features: The accused products are alleged to contain a multi-channel transceiver module with a transceiver housing and a dual fiber type direct link adapter that couples the internal TOSA and ROSA (Compl. 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 a plurality of optoelectronic diodes (photodetectors) and a light receiving chip are disposed directly on the same top surface of a carrier. An arrayed waveguide grating (AWG) is positioned to reflect de-multiplexed optical signals from its angled top surface directly onto the photosensitive surfaces of the diodes, simplifying alignment and manufacturing (Compl. Ex. F, p. 99, Abstract).
    • Asserted Claims: Independent claims 1 and 7 are asserted (Compl. ¶62).
    • Accused Features: The complaint alleges the accused products contain a multi-channel receiving device with a carrier, a light receiving chip, and optoelectronic diodes, where an AWG reflects light onto the diodes (Compl. Exs. L, M, N).

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

    • Technology Synopsis: The technology is an array of multiple optical isolators mounted on a single magnetic base. This integrated array structure simplifies the mounting and alignment of the isolators within an optical subassembly, as the entire array can be handled as a single unit (Compl. Ex. H, p. 123, Abstract).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶72).
    • Accused Features: The accused products are alleged to use an optical isolator array comprising multiple isolators on a first magnetic base, held in place by adhesive (Compl. 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: This patent addresses electrical interference within a transmitter optical subassembly (TOSA). It discloses routing the radio frequency (RF) signal traces and the power signal traces in an "opposing arrangement" on a substrate (e.g., on opposite surfaces of a printed circuit board) to provide electrical isolation and reduce interference between them (Compl. Ex. G, p. 109, Abstract).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶82).
    • Accused Features: The complaint alleges the accused TOSA modules utilize a substrate where power and RF traces are disposed in an opposing arrangement to achieve electrical isolation (Compl. 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: To prevent signal loss from excessive bending of internal optical fibers in compact transceivers, this invention positions the de-multiplexing device (e.g., an AWG) with its longitudinal center line laterally offset from the longitudinal center line of the main transceiver housing. This offset creates more space, allowing the internal fiber to be routed with a larger, less lossy bend radius (Compl. Ex. E, p. 84, Abstract).
    • Asserted Claims: Independent claims 1 and 16 are asserted (Compl. ¶92).
    • Accused Features: The accused transceivers are alleged to have an AWG device positioned off-center within the housing to manage the routing of an intermediate optical fiber (Compl. 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 an arrayed waveguide grating (AWG) device with a tapered region at its output. Light traveling through the AWG's waveguides reflects off an angled surface of this tapered region and is directed toward an output interface on the side of the AWG chip. This allows detector devices to be coupled directly to the side of the chip, eliminating the need for an intermediate fiber array and reducing optical signal loss (Compl. Ex. D, p. 70, Abstract).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶102).
    • Accused Features: The accused products are alleged to utilize an AWG chip with a tapered region that reflects light towards an exposed output interface for direct coupling to photodetectors (Compl. Exs. R, S, T).

III. The Accused Instrumentality

Product Identification

The accused products are a series of high-speed pluggable optical transceiver modules, specifically the "CIG 100G QSFP CWDM4 module Version 1, CIG 100G QSFP CWDM4 Module Version 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

These products are components used in fiber-optic networking equipment for data centers, telecommunications, and other high-bandwidth applications (Compl. ¶19). They function to convert electrical data signals into optical signals for transmission over fiber optic cables, and to convert received optical signals back into electrical data. The complaint provides photographic evidence of the accused products' internal construction in its claim chart exhibits (Compl. Exs. I-T). For example, a photograph in Exhibit I shows the exterior of an accused CIG 100G QSFP28 PSM4 module, identifying the main body and sliding release mechanism (Compl. Ex. I, p. 129, FIG. 1). Another image in Exhibit J shows the internal PCBA of the same product, identifying the transmitter, receiver, and passive optical element (Compl. Ex. J, p. 141, FIG. 2).

IV. Analysis of Infringement Allegations

9,523,826 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
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 transceiver has a metal main body (B) with two opposite side surfaces (C), each containing a sliding slot (D) (Compl. Ex. I, p. 129-130, FIGs. 1-2). ¶35; Ex. I col. 3:1-5
wherein the main body has at least one limiting space and two bottom surfaces forming the two sliding slots, respectively, The main body (B) contains at least one limiting space (E) and two bottom surfaces (F) that form the sliding slots (D) (Compl. Ex. I, p. 130-131, FIGs. 2-3). ¶35; Ex. I col. 3:6-12
a sliding component comprising a linkage arm and two extending arms...each extending arm has a second fastening part, The accused product includes a sliding component (G), shown as the blue pull-tab assembly, which comprises a linkage arm (H) and two extending arms (I). Each arm has a second fastening part (J) (Compl. Ex. I, p. 130, 132-133, FIGs. 2, 4, 5). ¶35; Ex. I col. 3:27-37
an elastic component, wherein the main body has a first limiting surface and a second limiting surface forming the limiting space... The accused product contains an elastic component (N) located within the limiting space (E). The main body (B) has a first limiting surface (L1) and a second limiting surface (L2) that form this space (Compl. Ex. I, p. 131, 135, FIG. 3). ¶35; Ex. I col. 4:11-19
and 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... The elastic component (N) is allegedly located between the first limiting surface (L1) and the limited part (K), and is allegedly confined by the main body (B) and the sliding component (G) (Compl. Ex. I, p. 135). ¶35; Ex. I col. 4:11-19; 34:49-54
  • Identified Points of Contention:
    • Scope Questions: The analysis may focus on the term "covered by the extending arm." The complaint's visual evidence shows the elastic component (a spring) resides within a recess in the main body (Compl. Ex. I, p. 131, FIG. 3). A key question for claim construction will be whether being situated in such a recess, underneath the path of the extending arm's limited part, satisfies the "covered by" limitation as it is described and claimed in the patent.

10,466,432 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a printed circuit board assembly (PCBA) component having a receiver and a transmitter; and a passive optical element, The accused product contains a PCBA (A) that includes a receiver (B) and a transmitter (C), as well as a passive optical element (D) (Compl. Ex. J, p. 140-142, FIGs. 1-3). ¶44; Ex. J col. 3:10-12
the receiver comprises an amplifier chip and a photodiode array connected to pins of the amplifier chip; The receiver (B) allegedly includes an amplifier chip (E) and a photodiode array (F), with the array connected to the chip's pins via wire bonds (M) (Compl. Ex. J, p. 143, FIG. 4). A photograph in Exhibit J shows a close-up of these components (Compl. Ex. J, p. 143, FIG. 4). ¶44; Ex. J col. 3:13-16
the transmitter comprises a laser driving chip and a base; the base comprises a plurality of lasers arranged side by side; The transmitter (C) allegedly includes a laser driving chip (G) and a base (H). The base (H) comprises a plurality of lasers (I) arranged side-by-side (Compl. Ex. J, p. 141, FIG. 2). ¶44; Ex. J col. 3:16-20
a plurality of fiber interfaces are arranged on output light paths corresponding to the lasers; The accused product has a plurality of fiber interfaces (J) arranged on the output light paths corresponding to the lasers (I) (Compl. Ex. J, p. 141, FIG. 2). ¶44; Ex. J col. 3:20-22
the passive optical element comprises ferrules corresponding to the fiber interfaces...and the ferrules are inserted into the plurality of fiber interfaces in one-to-one correspondence. The passive optical element (D) allegedly comprises ferrules (L) that correspond to the fiber interfaces (J). The complaint alleges these ferrules are inserted into the fiber interfaces in a one-to-one correspondence (Compl. Ex. J, p. 141, FIG. 2). ¶44; Ex. J col. 3:22-27
  • Identified Points of Contention:
    • Technical Questions: The central inventive concept of the ’432 Patent is the modular, non-soldered assembly. A primary technical question will be evidentiary: what proof demonstrates that the ferrules in the accused CIG product are "inserted into" the fiber interfaces, as opposed to being attached by another means (e.g., adhesive, press-fitting) that might fall outside the scope of the claims as construed by the court? The nature of this physical connection will be a critical factual dispute.

V. Key Claim Terms for Construction

U.S. Patent No. 9,523,826

  • The Term: "covered by the extending arm such that the elastic component is confined by the main body and the sliding component" (Claim 1)
  • Context and Importance: This limitation is critical because it defines the precise structural arrangement of the spring mechanism that biases the sliding component. The infringement analysis will turn on whether the accused product's design, where a spring sits in a recess of the main body, meets this "covered by" and "confined" requirement. Practitioners may focus on this term because the visual evidence suggests a potential mismatch between the claim language and the accused structure.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent's objective is to describe a functional relationship where the spring (elastic component) is held in place and acts upon the sliding component. Language describing the overall function, such as how the elastic component "normally presses the limited part" (Compl. Ex. A, p. 33, col. 4:21-23), could support a broader, less structurally rigid interpretation of "covered."
    • Evidence for a Narrower Interpretation: Claim 1 explicitly states the elastic component is "covered by the extending arm." The patent figures, such as the cross-section in FIG. 4A, show the elastic component (400) situated within the limiting space (150) of the main body (100) and acted upon by the limited part (240) of the extending arm. A defendant may argue that "covered" requires the arm itself to form a ceiling or enclosure over the spring, an arrangement that may not be present in the accused device.

U.S. Patent No. 10,466,432

  • The Term: "the ferrules are inserted into the plurality of fiber interfaces" (Claim 1)
  • Context and Importance: This phrase captures the core of the invention: a modular assembly that avoids soldering. The case may hinge on the definition of "inserted into." If the term is construed to mean a specific type of plug-and-receptacle connection, and the accused product uses a different non-soldered method (e.g., adhesive bonding into a channel), infringement could be avoided.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The background repeatedly criticizes the unreliability and complexity of "soldered connection[s]" (Compl. Ex. B, p. 44, col. 1:26-29). The summary contrasts this with the invention where the "passive optical element is inserted into the PCBA component" and the connection is "convenient, effective, and stable without resorting to soldering" (Compl. Ex. B, p. 44, col. 1:56-2:1). This context may support a broad construction where "inserted into" means any non-soldered physical engagement.
    • Evidence for a Narrower Interpretation: The detailed description states that "the ferrules are correspondingly inserted into the fiber interfaces in another one-to-one relationship" (Compl. Ex. B, p. 45, col. 3:24-27). This language, combined with figures like FIG. 3 showing the assembly of two distinct components, may support a narrower definition requiring a separable, plug-like insertion rather than a more permanent bonding with adhesive.

VI. Other Allegations

  • Indirect Infringement: The complaint does not provide sufficient detail for analysis of indirect infringement. The causes of action focus on allegations of direct infringement (Compl. ¶¶34, 43, 52, 62, 72, 82, 92, 102).
  • Willful Infringement: The complaint alleges willful infringement for six of the eight asserted patents (’383, ’301, ’690, ’024, ’431, and ’116). The basis for this allegation is pre-suit knowledge stemming from a detailed notice letter and claim charts sent to Defendant's CEO on October 20, 2023 (Compl. ¶¶55, 65, 75, 85, 95, 105, 108). For the remaining two patents (’826 and '432), the complaint alleges knowledge as of the filing of the original complaint, which may support a claim for post-suit willfulness (Compl. ¶¶37, 46).

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

  • A core issue will be one of definitional scope: can the mechanical term "covered by the extending arm" from the '826 patent, which describes the placement of a spring, be construed to read on the accused product's design where the spring sits within a recess of the main housing? This question highlights the classic patent litigation tension between the literal claim language and the physical embodiment of an accused product.
  • A second central issue will be one of technical assembly: for the '432 patent and others related to modular design, does the physical connection between the accused product's optical components and its PCBA meet the claimed "insertion" of ferrules into interfaces? The case may require a factual determination of how the accused devices are actually manufactured to resolve whether the connection is a separable insertion or a more permanent, albeit non-soldered, bonding.
  • A third critical question will be culpability and damages: given that Plaintiff allegedly provided detailed pre-suit notice, including claim charts, for six of the eight patents, a key focus for the court will be whether Defendant's subsequent alleged infringement was willful. The outcome of this question could significantly impact any potential damages award.