DCT

4:24-cv-09041

Applied Optoelectronics Inc v. Accelight Tech Inc

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Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 4:24-cv-09041, N.D. Cal., 02/19/2025
  • Venue Allegations: Plaintiff alleges venue is proper because Defendant has a regular and established place of business in the Northern District of California and has allegedly committed acts of infringement in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s high-speed optical transceiver modules infringe six patents related to the mechanical design, internal optical architecture, electronic layout, and component configuration of such devices.
  • Technical Context: The technology at issue involves pluggable fiber-optic transceivers, which are fundamental components for high-speed data transmission in markets such as internet data centers, telecommunications, and cable television networks.
  • Key Procedural History: The operative pleading is a First Amended Complaint. Plaintiff alleges Defendant has had knowledge of the asserted patents and its alleged infringement since at least the filing of the original complaint in this action.

Case Timeline

Date Event
2012-12-10 ’367 Patent Priority Date
2013-10-02 ’826 Patent Priority Date
2016-04-25 ’116 Patent Priority Date
2016-05-23 ’301 Patent Priority Date
2016-09-20 ’367 Patent Issued
2016-12-20 ’826 Patent Issued
2018-04-26 ’024 Patent Priority Date
2018-08-07 ’116 Patent Issued
2019-01-25 ’690 Patent Priority Date
2019-06-04 ’024 Patent Issued
2019-08-13 ’301 Patent Issued
2020-09-29 ’690 Patent Issued
2025-02-19 First Amended Complaint Filed

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

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

  • The Invention Explained:
    • Problem Addressed: The patent describes the need for a reliable and convenient mechanism to securely fasten pluggable optical transceiver modules into sockets within electronic equipment and to easily release and remove them, while also protecting the internal electronics from dust contamination (p. 23, col. 1:20-51).
    • The Patented Solution: The invention is a mechanical design for a transceiver module featuring a main body and a separate sliding component. This sliding component includes extending arms that interact with fastening parts in a corresponding socket. When a user pulls a handle, the sliding component moves, and inclined surfaces on its "second fastening parts" press against the socket's "first fastening parts," forcing them to spread apart and release the module from the socket (’826 Patent, Abstract; col. 4:32-52). The design of the sliding slots on the main body is also described as protecting internal components from dust (’826 Patent, col. 3:20-24).
    • Technical Importance: This design sought to improve the ease of connecting and disconnecting high-density optical modules and enhance their reliability by providing a dust-proof function (’826 Patent, col. 1:48-51).
  • Key Claims at a Glance:
    • The complaint asserts independent claims 1 and 7 (’826 Patent, col. 5:12, col. 6:49; Compl. ¶23).
    • Claim 1 Essential Elements:
      • A pluggable optical transceiver module comprising a main body and a sliding component.
      • The main body has two opposite side surfaces, two sliding slots, and at least one limiting space.
      • The sliding component has a linkage arm and two extending arms, with each arm having a second fastening part and a limited part.
      • The extending arms are slidably disposed in the sliding slots to move between a fastening position and a releasing position.
      • An elastic component, confined within the limiting space, is positioned between a limiting surface on the main body and the limited part of the extending arm.
    • Claim 7 Essential Elements:
      • A pluggable optical transceiver module comprising a main body, a sliding component, and an elastic component.
      • The main body has a head part, an inserted part, opposite side surfaces, two sliding slots extending from the head part to the inserted part, and at least one limiting space with first and second limiting surfaces.
      • The sliding component has a linkage arm and two extending arms, with each arm having a second fastening part and a limited part configured to move in the limiting space.
      • The elastic component is located in the limiting space between the first limiting surface and the limited part and is covered by the extending arm.

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"

  • The Invention Explained:
    • Problem Addressed: The patent explains that conventional receiver optical subassemblies (ROSAs) use an intermediate fiber array to guide light from a demultiplexer (which separates a signal into different wavelengths) to an array of photodetectors. This fiber array introduces significant optical power loss, or "insertion loss," which reduces receiver sensitivity and overall performance (’116 Patent, col. 3:7-21).
    • The Patented Solution: The invention is an Arrayed Waveguide Grating (AWG) chip that eliminates the need for an intermediate fiber array. The output end of the AWG chip is formed into a "tapered region" with an angled surface. This surface acts as a mirror, reflecting the demultiplexed light signals downwards (substantially orthogonally) through an "exposed output interface region" on the bottom of the chip. This allows the light to be directly coupled to an array of photodetectors placed immediately adjacent to this interface (’116 Patent, Abstract; col. 4:1-32).
    • Technical Importance: This direct-coupling architecture is designed to reduce insertion loss by at least 1-2 dB, thereby improving receiver sensitivity, while also enabling a more compact physical design for high-density optical modules (’116 Patent, col. 4:54-65).
  • Key Claims at a Glance:
    • The complaint asserts independent claims 1 and 12 (’116 Patent, col. 11:18, col. 12:48; Compl. ¶32).
    • Claim 1 Essential Elements (AWG Chip):
      • An AWG chip with a first end for receiving an optical signal, a substrate, and a planar lightwave circuit (PLC) on the substrate to de-multiplex the signal.
      • A plurality of output waveguides to carry the de-multiplexed light along a first light path toward a second end of the chip.
      • A tapered region at the second end that receives light from the waveguides and reflects it toward an exposed output interface region.
      • The exposed output interface region emits the reflected light from the same side of the chip as the substrate, without the light passing through the substrate.
    • Claim 12 Essential Elements (Optical Transceiver Module):
      • A transceiver housing.
      • A multi-channel receiver optical sub-assembly (ROSA) located in the housing, which includes the AWG chip recited in Claim 1.
      • An array of detector devices disposed adjacent to the output interface region of the AWG chip.
      • A multi-channel transmitter optical assembly (TOSA) for transmitting optical signals.

Multi-Patent Capsule Summaries

  • U.S. Patent No. 9,448,367

    • Title: "Multi-Channel Optical Transceiver Module Including Dual Fiber Type Direct Link Adapter for Optically Coupling Optical Subassemblies in the Transceiver Module"
    • Technology Synopsis: The patent addresses the challenge of fitting optical connection components within small form-factor transceivers (’367 Patent, col. 1:56-65). The invention is a compact "dual fiber type direct link adapter" that creates a direct, non-pluggable optical fiber link between the internal transmitter/receiver subassemblies and an external-facing receptacle for pluggable connectors (e.g., LC connectors), thereby saving space (’367 Patent, col. 2:32-47).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶40).
    • Accused Features: The complaint alleges that the adapter body and connector assemblies in Defendant's products, such as the ATI 400G QSFP-DD FR4, infringe the ’367 patent (Compl. ¶41, Ex. K).

  • U.S. Patent No. 10,379,301

    • Title: "Multi-channel parallel optical receiving device"
    • Technology Synopsis: This patent describes a multi-channel optical receiving device designed for simplified manufacturing and reduced cost (’301 Patent, col. 1:29-35). Similar to the '116 patent, the solution involves an arrayed waveguide grating (AWG) on a carrier, where the output end of the AWG has a top surface at a predetermined angle (e.g., 41-46 degrees) to reflect multi-channel optical signals directly onto photosensitive diodes arranged in parallel, simplifying alignment and assembly (’301 Patent, col. 1:36-54).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶49).
    • Accused Features: The complaint alleges that the receiver subassembly in products like the ATI 100G QSFP28 CWDM4, which includes a carrier, an AWG, and optoelectronic diodes, infringes the ’301 patent (Compl. ¶50, Ex. L).

  • U.S. Patent No. 10,313,024

    • Title: "Transmitter Optical Subassembly With Trace Routing To Provide Electrical Isolation Between Power And RF Traces"
    • Technology Synopsis: The patent addresses electrical interference in compact TOSA modules, where high-frequency radio frequency (RF) signal traces and direct current (DC) power traces must be routed in close proximity (’024 Patent, col. 2:13-19). The invention provides a substrate for the TOSA's driving circuitry where RF signal traces are routed on one surface and power-related traces (DC and ground) are routed on the opposite surface, using the substrate itself for electrical isolation (’024 Patent, col. 2:20-33).
    • Asserted Claims: Independent claims 1 and 12 are asserted (Compl. ¶58).
    • Accused Features: The complaint alleges that the layout of the substrate and electrical traces within the TOSA modules of Defendant's products, such as the ATI 100G QSFP LR4, infringes the ’024 patent (Compl. ¶59, Ex. M).

  • U.S. Patent No. 10,788,690

    • Title: "Optical Isolator Array For Use In An Optical Subassembly Module"
    • Technology Synopsis: The patent addresses challenges in manufacturing multi-channel optical subassemblies that require multiple optical isolators, which must be individually aligned (’690 Patent, col. 1:30-44). The solution is a monolithic "optical isolator array" where multiple isolator elements are pre-mounted on a single magnetic base, allowing the entire array to be manufactured separately and then installed and aligned as a single unit, simplifying assembly and reducing manufacturing complexity (’690 Patent, Abstract).
    • Asserted Claims: Independent claims 1 and 11 are asserted (Compl. ¶67).
    • Accused Features: The complaint alleges that the array of optical isolators mounted on a magnetic base within the TOSA of Defendant's products, such as the ATI 400G QSFP-DD DR4, infringes the ’690 patent (Compl. ¶68, Ex. N).

III. The Accused Instrumentality

  • Product Identification: The accused products include the ATI 100G QSFP LR4, ATI 400G QSFP-DD SR8, ATI 100G QSFP28 CWDM4, ATI 400G QSFP-DD FR4, and ATI 400G QSFP-DD DR4 (Compl. ¶18).
  • Functionality and Market Context: These products are high-speed, pluggable fiber-optic transceiver modules designed for use in networking equipment for end-markets that include internet data centers, cable television broadband, and telecommunications (Compl. ¶16, ¶18). The complaint provides annotated photographs of these products, which are alleged to contain the mechanical, optical, and electronic structures covered by the patents-in-suit. For example, an annotated photograph of the ATI 100G QSFP LR4 shows a "main body" and a "sliding component" alleged to map to claim terms of the '826 patent (Compl. Ex. G, FIG. 1-2).

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, for being inserted into a plugging slot of a socket... The accused product is a pluggable optical transceiver module for being inserted into a socket. ¶23; Ex. G col. 1:12-14
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 has a main body with two opposite side surfaces and two sliding slots located on those surfaces. An annotated photograph in the complaint identifies the "main body," "side surface," and "sliding slot" (Compl. Ex. G, FIG. 1, 2, 4). ¶23; Ex. G col. 3:1-7
wherein the main body has at least one limiting space and two bottom surfaces forming the two sliding slots...the two bottom surfaces are parallel to the two side surfaces... The accused product's main body allegedly contains at least one limiting space and parallel bottom surfaces forming the sliding slots. ¶23; Ex. G col. 3:10-14
a sliding component comprising a linkage arm and two extending arms...each extending arm has a second fastening part... The accused product has a sliding component with a linkage arm and two extending arms, each with a second fastening part. An annotated photograph identifies these components (Compl. Ex. G, FIG. 2, 3). ¶23; Ex. G col. 3:25-34
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 confined... The accused product contains an elastic component (a coil spring) located in a limiting space between limiting surfaces of the main body and a limited part of the extending arm, where it is allegedly confined by the main body and sliding component. ¶23; Ex. G col. 5:48-55
  • Identified Points of Contention:
    • Scope Questions: The analysis may turn on the construction of "confined by the main body and the sliding component." The parties may dispute whether the accused product's spring is "confined" in the specific manner required by the claim, or if it is merely situated in a cavity without meeting the functional and structural aspects of the claimed confinement.
    • Technical Questions: What evidence does the complaint provide that the accused mechanism performs the claimed releasing function, i.e., that the "second fastening parts press the two first fastening parts... to make the two first fastening parts be farther away from each other"? The complaint provides static images but no evidence of the components interacting during operation.

’116 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An arrayed waveguide grating (AWG) chip comprising: a first end for coupling to an optical coupling receptacle...a substrate; a planar lightwave circuit (PLC) disposed on the substrate... The accused product's ROSA contains an AWG chip with a substrate, a PLC, and a first end for coupling to a receptacle. Annotated photographs identify these components (Compl. Ex. J, FIG. 1, 2). ¶32; Ex. J col. 11:18-28
a plurality of output waveguides coupled to the PLC...to provide the light along a first light path that extends towards a second end of the AWG chip... The accused AWG chip has multiple output waveguides that carry de-multiplexed light toward the second end of the chip. ¶32; Ex. J col. 11:29-35
a tapered region disposed at the second end of the AWG chip configured to receive light...and reflect the same towards an exposed output interface region of the AWG chip... The second end of the accused AWG chip allegedly has a tapered region with an angled surface that reflects light toward an output interface region. A micrograph in the complaint purports to show this "tapered region" and the "first light path" of the light being reflected (Compl. Ex. J, FIG. 3). ¶32; Ex. J col. 11:36-41
wherein the exposed output interface region emits the received light from the AWG chip on the same side as the substrate without passing the received light through the substrate. The output interface region of the accused AWG chip allegedly emits light from the same side as its substrate, directly onto an adjacent array of detector devices, without the light passing through the substrate itself. A photograph shows the detector array positioned next to the AWG chip (Compl. Ex. J, FIG. 4). ¶32; Ex. J col. 11:41-45
  • Identified Points of Contention:
    • Scope Questions: A central issue may be the meaning of "exposed output interface region." The parties may dispute what structural and functional characteristics are required for a surface to qualify as this region, particularly concerning how it "emits" light and its relationship to the substrate.
    • Technical Questions: What is the precise path of light within the accused ROSA? The infringement allegation hinges on the claim that a "tapered region" reflects light orthogonally onto detectors from the bottom surface of the chip. The case may require expert testimony and potentially destructive analysis of the accused products to verify this internal optical functionality.

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 fastening mechanism. The manner in which the elastic component is "confined" and interacts with the "limiting space" and "limited part" distinguishes it from a generic spring. The outcome of the case for this patent may depend on whether the accused product's spring meets this specific structural and functional confinement limitation.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification refers to the element simply as an "elastic component," which is a broad term (’826 Patent, col. 2:62). One could argue that any spring that provides a biasing force within the general area fits the description.
      • Evidence for a Narrower Interpretation: Claim 1 explicitly 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" (’826 Patent, col. 5:51-55). This language suggests a specific positional and enclosing relationship, as depicted in FIG. 4A and 4B, which show a coil spring fully enclosed within a cavity formed by parts of both the main body and the sliding component.

  • For the ’116 Patent:

    • The Term: "tapered region"
    • Context and Importance: This is the key structural feature of the invention, responsible for reflecting light to achieve the direct coupling that avoids the prior art's fiber array. Its definition will determine whether various angled-end chip designs infringe. Practitioners may focus on this term because the functionality of reflecting light "towards an exposed output interface region" is tied directly to the structure of this region.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification states the tapered region may be formed by "cutting away and polishing a portion of the AWG chip such that an angled surface is formed" (’116 Patent, col. 4:8-11). This focuses on the result (an angled surface) rather than a specific geometry, potentially supporting a broader reading.
      • Evidence for a Narrower Interpretation: The dependent claims add limitations like the angled surface extending between sidewalls (claim 3) and having an interior angle of about 41 to 45 degrees (claim 4). While not in the independent claim, this context suggests the "tapered region" is not just any angled surface but one specifically engineered to achieve total internal reflection at a near-orthogonal angle, as illustrated in FIG. 8.

VI. Other Allegations

  • Willful Infringement: The complaint does not contain an explicit count for willful infringement. However, for each asserted patent, it alleges that the Defendant "has knowledge and notice of the Asserted Patents and its infringement since at least, and through, the filing of the original complaint in this action" (Compl. ¶25, ¶34, ¶43, ¶52, ¶61, ¶70). This allegation may form the basis for seeking enhanced damages for any post-filing infringement.

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

  • A central issue will be one of functional and structural correspondence for mechanical claims: Do the moving parts of the accused transceivers—specifically the release lever and the internal connector adapter—operate in the specific manner recited by the ’826 and ’367 patents, or are they merely structurally similar but functionally distinct implementations of common industry designs?
  • A key evidentiary question will concern the internal optical path: Does discovery, including potential reverse engineering of the accused devices, confirm the complaint's allegation that Defendant's receiver subassemblies employ a "tapered region" on an AWG chip to reflect light orthogonally onto an adjacent detector array, as required by the ’116 and ’301 patents?
  • The case will also present questions of internal component architecture: Does the electronic layout of the accused transmitter modules intentionally segregate power and RF traces on opposite sides of a substrate to mitigate interference as claimed in the ’024 patent, and do they incorporate a monolithic array of optical isolators on a single magnetic base as claimed in the ’690 patent?