Applied Optoelectronics, Inc. v. Eoptolink Technology USA Inc.

Applied Optoelectronics, Inc. (AOI), a Texas-based operating company, is a prominent developer and manufacturer of fiber-optic networking products, including optical transceivers, laser chips, and other components, serving internet data centers, cable television, and telecom markets globally. Defendant Eoptolink Technology USA Inc., a subsidiary of Eoptolink Technology Inc., Ltd. (a Chinese company), is also an operating company specializing in the design, development, manufacturing, and marketing of high-performance optical transceiver modules for various applications, including enterprise, access, metro, and core networks, with a customer base that includes cloud data centers and telecom equipment makers. This litigation, therefore, pits two direct competitors in the optical communications and transceiver industry against each other.

The lawsuit alleges that Eoptolink Technology USA Inc. infringes Applied Optoelectronics' patents. While the specific accused products are not detailed in the provided search snippets, the nature of both companies' businesses strongly suggests that the alleged infringement relates to optical transceiver modules or components used in high-speed data transmission. The primary patent at issue, US Patent No. 9,448,367B2, is one of six patents asserted by AOI in this case. A brief technical sketch of this patent, without direct access to its full claims, would broadly cover technology related to optical communications, likely involving aspects of optical transceivers, their design, or methods of operation within fiber-optic networks.

The case, Applied Optoelectronics, Inc. v. Eoptolink Technology USA Inc., case number 5:24-cv-08165-NW, is currently being heard in the United States District Court for the Northern District of California, San Jose Division. The case is presently stayed pending institution decisions for multiple Inter Partes Reviews (IPRs) at the Patent Trial and Appeal Board (PTAB), which is a common procedural posture in patent litigation when the validity of asserted patents is challenged at the USPTO. This linkage to IPRs makes the case notable, as the outcome of the PTAB proceedings will directly impact the scope and continuation of the district court litigation. The Northern District of California is a prominent venue for patent cases, especially those involving technology companies, due to its specialized judiciary and its proximity to Silicon Valley's tech industry.

Applied Optoelectronics, Inc. initiated a patent infringement lawsuit against Eoptolink Technology USA Inc. in the United States District Court for the Northern District of California, San Jose Division, under Case No. 5:24-cv-08165-NW. The litigation involves six patents, with US patent 9,448,367B2 being one of them.

Key legal developments and the current posture of the case are as follows:

• Filing & Initial Pleadings: The complaint was filed on November 19, 2024, by Applied Optoelectronics, Inc., alleging infringement of six patents. While the content of Eoptolink's answer or any counterclaims is not explicitly detailed, it is noted that Eoptolink alleges the invalidity of each of the six patents-in-suit.
• Pre-trial Motions of Substance: On December 5, 2025, both parties filed a Joint Administrative Motion to Stay Pending IPR Institution Decisions. The motion highlighted that Eoptolink had filed petitions for inter partes review (IPR) for four of the asserted patents and intended to file requests for ex parte reexamination for the remaining two.
• Stay Pending IPR: The District Court granted the joint motion on January 13, 2026, issuing an order that stayed the case until June 5, 2026. All existing deadlines were vacated. The court also scheduled a further case management conference for June 30, 2026, and mandated a joint case management statement by June 12, 2026.
• Claim Construction (Markman) Outcomes: Prior to the stay, the parties were scheduled to exchange preliminary claim constructions and extrinsic evidence by December 19, 2025, and file a Joint Claim Construction and Prehearing Statement and Expert Reports by January 13, 2026, with claim construction briefing set to commence in February 2026. However, these deadlines were vacated when the stay was granted. Therefore, no Markman outcomes or significant discovery milestones have occurred beyond the initial disclosures and exchange of infringement and invalidity contentions, which took place between June and December 2025.
• Parallel PTAB IPR Proceedings: Eoptolink initiated several IPR proceedings against the asserted patents:
  • On October 10, 2025, Eoptolink filed an IPR petition challenging U.S. Patent No. 9,448,367 (IPR2026-00019).
  • On November 5, 2025, an IPR petition was filed for U.S. Patent No. 10,578,818 (IPR2026-00094).
  • On November 25, 2025, an IPR petition was filed for U.S. Patent No. 10,714,890 (IPR2026-00122).
  • On December 1, 2025, an IPR petition was filed for U.S. Patent No. 11,177,887 (IPR2026-00123).
    Eoptolink also plans to file requests for ex parte reexamination for U.S. Patent Nos. 9,509,433 and 10,230,470. The district court's stay order requires the parties to file a joint status report within seven days of any decision from the United States Patent and Trademark Office regarding the institution of these IPRs.
• Outcome/Present Posture: The case is currently stayed pending the institution decisions of the IPRs. No trial events, verdicts, post-trial motions, settlement, or final judgment have occurred. The stay is in effect until at least June 5, 2026.

Plaintiff Applied Optoelectronics, Inc. (AOI) is represented by attorneys from Weintraub Tobin Chediak Coleman Grodin Law Corporation, and potentially by additional firms for specialized patent litigation aspects, such as post-grant proceedings or specific technical expertise.

Here's a breakdown of the identified counsel:

• Jo Dale Carothers

  • Role: Counsel
  • Firm: Weintraub Tobin Chediak Coleman Grodin Law Corporation
  • Office Location: San Francisco, CA
  • Relevant Experience: Jo Dale Carothers is listed as counsel for Applied Optoelectronics, Inc. on a joint administrative motion to stay the case.

• Eric A. Caligiuri

  • Role: Counsel
  • Firm: Weintraub Tobin Chediak Coleman Grodin Law Corporation
  • Office Location: San Francisco, CA
  • Relevant Experience: Eric A. Caligiuri is also listed as counsel for Applied Optoelectronics, Inc. on the joint administrative motion to stay the case.

It's important to note that for complex patent litigation, especially cases involving multiple patents and parallel PTAB proceedings like this one, plaintiffs often engage a team of attorneys, including lead counsel for district court litigation, specialized counsel for PTAB matters, and potentially attorneys with specific technical expertise relevant to the patents at issue. While Weintraub Tobin Chediak Coleman Grodin Law Corporation are listed as "Attorneys for Plaintiff" on the joint motion to stay, additional counsel may be involved in different capacities.

David Kuo is identified as the General Counsel of Applied Optoelectronics, Inc., indicating he is likely involved as in-house counsel, managing the legal aspects and risks for AOI.

The following counsel represent defendant Eoptolink Technology USA Inc. in Applied Optoelectronics, Inc. v. Eoptolink Technology USA Inc., Case No. 5:24-cv-08165-NW:

• Robert F. McCauley (Lead Counsel)
  • Firm: Perkins Coie LLP, Palo Alto, California.
  • Experience: Robert McCauley is listed as counsel for Eoptolink Technology USA Inc. on multiple filings in this patent infringement case, including the Joint Administrative Motion to Stay and Invalidity Contentions. His practice focuses on intellectual property litigation, including patent, trade secret, trademark, and copyright disputes, and he has significant experience representing clients in the technology sector.
• Arpita Bhattacharyya (Counsel)
  • Firm: Perkins Coie LLP, Palo Alto, California.
  • Experience: Arpita Bhattacharyya is also listed as counsel for Eoptolink Technology USA Inc. in filings related to this patent infringement lawsuit. Her experience includes patent litigation and other intellectual property matters.