Untitled case

The patent infringement litigation 5:24-cv-08165, currently unfolding in the United States District Court for the Northern District of California, involves two operating companies in the high-speed optical transceiver industry. The plaintiff, Applied Optoelectronics, Inc. (AOI), a Delaware company, manufactures optical transceiver products. The defendant, Eoptolink Technology USA Inc., a California company, is accused of infringing AOI's patents with its own optical transceiver products, specifically high-speed, pluggable fiber-optic transceivers, including the 100G LR4 (QL97099330) product.

The case asserts U.S. Patent No. 9,448,367 ("the '367 patent"), among others. The '367 patent generally relates to a "Multi-Channel Optical Transceiver Module Including Dual Fiber..." and the infringement allegations focus on features such as direct link connector assemblies defining an LC connector receptacle for optical coupling and an adapter cover portion designed to retain these assemblies. The litigation is being overseen by Judge Noël Wise in the San Jose Division. The Northern District of California is a notable venue for patent cases, known for its experienced judiciary, its willingness to consider early dispositive motions like Alice challenges, and its tendency to grant stays pending inter partes review (IPR) decisions, as governed by its specific local patent rules.

The procedural posture of the case is currently stayed. Eoptolink filed IPR petitions challenging the patentability of four of the six patents asserted by AOI in this action, including the '367 patent, and plans to file requests for ex parte reexamination for the remaining two. Consequently, on January 13, 2026, the court granted a joint administrative motion to stay the case, vacating all deadlines until June 5, 2026, pending the Patent Trial and Appeal Board's (PTAB) institution decisions on the IPRs. A further case management conference is scheduled for June 30, 2026. This case is notable due to the significant role of the asserted patents in the critical infrastructure of internet data centers and telecommunications networks, and for demonstrating the common strategy of using IPRs to influence or pause district court litigation.

The patent infringement litigation, Applied Optoelectronics, Inc. v. Eoptolink Technology USA Inc., Case No. 5:24-cv-08165-NW, was filed in the U.S. District Court for the Northern District of California. Applied Optoelectronics, Inc. (AOI) is the plaintiff, and Eoptolink Technology USA Inc. is the defendant. The case was originally filed on November 19, 2024, and an operative First Amended Complaint was filed on March 7, 2025. AOI alleges that Eoptolink infringes six patents related to multi-channel optical transceivers, including U.S. Patent No. 9,448,367 (the '367 patent).

Key legal developments include:

• Filing & Initial Pleadings:

  • The initial complaint was filed by Applied Optoelectronics, Inc. against Eoptolink Technology USA Inc. on November 19, 2024.
  • An operative First Amended Complaint was filed on March 7, 2025, asserting infringement of six patents, including the '367 patent.
  • On June 13, 2025, AOI served its infringement contentions.
  • On August 18, 2025, Eoptolink served its invalidity contentions, asserting that each of the six patents-in-suit is invalid.

• Pre-trial Motions of Substance:

  • On December 5, 2025, the parties filed a joint administrative motion to stay the case pending inter partes review (IPR) institution decisions.
  • On January 13, 2026, the Court granted the joint motion to stay, vacating all deadlines and staying the case until June 5, 2026, pending institution decisions on Eoptolink's IPR petitions. The Court has set a further case management conference for June 30, 2026, with a joint case management statement due by June 12, 2026.

• Parallel PTAB IPR Proceedings:

  • Beginning in October 2025, Eoptolink filed IPR petitions challenging the patentability of the asserted claims of four of the six patents asserted in the district court action. Eoptolink also plans to file requests for ex parte reexamination against the remaining two patents.
  • Specifically, Eoptolink filed IPR petitions challenging U.S. Patent No. 9,448,367 (the '367 patent, jointly with another party), U.S. Patent No. 10,578,818 (the '818 patent), U.S. Patent No. 11,177,887 (the '887 patent), and U.S. Patent No. 10,714,890 (the '890 patent).
  • AOI has filed requests with the Director for discretionary denial of Eoptolink's IPR petitions for the '367 and '818 patents, citing similar grounds as those asserted in its request for the '890 patent. The IPR proceedings are cited as IPR2026-00019 (for the '367 patent), IPR2026-00122 (for the '890 patent), among others.

• Present Posture:

  • The litigation is currently stayed until June 5, 2026, pending decisions from the USPTO on whether to institute the IPRs. A further case management conference is scheduled for June 30, 2026.The patent infringement litigation, Applied Optoelectronics, Inc. v. Eoptolink Technology USA Inc., Case No. 5:24-cv-08165-NW, is currently active in the U.S. District Court for the Northern District of California. Applied Optoelectronics, Inc. (AOI) is the plaintiff, and Eoptolink Technology USA Inc. is the defendant. The core dispute involves allegations that Eoptolink's optical transceiver products infringe six patents, including U.S. Patent No. 9,448,367, which relate to the mechanical and electrical design, component arrangement, and assembly of multi-channel optical transceivers.

Here is a chronological overview of the key legal developments:

• Filing & Initial Pleadings:

  • 2024-11-19: Applied Optoelectronics, Inc. filed its initial complaint against Eoptolink Technology USA Inc.
  • 2025-03-07: An operative First Amended Complaint was filed, which superseded the original complaint and asserted infringement of six patents.
  • 2025-06-13: AOI served its infringement contentions to Eoptolink.
  • 2025-08-18: Eoptolink served its invalidity contentions, alleging that all six asserted patents are invalid.

• Pre-trial Motions of Substance:

  • 2025-12-05: The parties jointly filed an administrative motion requesting a stay of the district court proceedings pending institution decisions on inter partes review (IPR) petitions filed by Eoptolink.
  • 2026-01-13: The District Court granted the joint motion to stay. The Court vacated all existing deadlines and stayed the case until June 5, 2026, specifically pending the institution decisions from the United States Patent and Trademark Office (USPTO) regarding Eoptolink's IPR petitions.
  • 2026-06-30: A further case management conference has been scheduled, with a joint case management statement due by June 12, 2026.

• Parallel PTAB IPR Proceedings:

  • October 2025 (beginning): Eoptolink initiated IPR proceedings by filing petitions challenging the patentability of claims in four of the six patents asserted in the district court litigation. Eoptolink also intends to file requests for ex parte reexamination against the remaining two patents.
  • The IPR petitions include challenges to U.S. Patent No. 9,448,367 (IPR2026-00019, filed jointly with another party), U.S. Patent No. 10,578,818, U.S. Patent No. 11,177,887, and U.S. Patent No. 10,714,890 (IPR2026-00122).
  • AOI has filed requests with the Director of the USPTO for discretionary denial of Eoptolink's IPR petitions for the '367 and '818 patents, citing similar reasons as those presented in its request for the '890 patent. The IPR petitions and the associated requests for discretionary denial are ongoing.

• Final Disposition or Present Posture:

  • The litigation remains active but is currently stayed until June 5, 2026, awaiting institution decisions from the USPTO on the IPR petitions. A case management conference is set for June 30, 2026.

In the patent infringement case 5:24-cv-08165 in the California Northern District Court, the plaintiff, Applied Optoelectronics, Inc., is represented by the following counsel:

• Jo Dale Carothers

  • Role: Attorney for Plaintiff (likely lead or appearing counsel).
  • Firm: Weintraub Tobin Chediak Coleman Grodin Law Corporation, San Francisco, CA.
  • Experience Note: Carothers is listed as an attorney for Plaintiff Applied Optoelectronics, Inc. in this case.

• Eric A. Caligiuri

  • Role: Attorney for Plaintiff (likely lead or appearing counsel).
  • Firm: Weintraub Tobin Chediak Coleman Grodin Law Corporation, San Francisco, CA.
  • Experience Note: Caligiuri is listed as an attorney for Plaintiff Applied Optoelectronics, Inc. in this case.

Counsel of Record for Defendant Eoptolink Technology USA Inc.

The defendant in this patent infringement case, Eoptolink Technology USA Inc., is represented by attorneys from Perkins Coie LLP.

Here are the details for the identified counsel:

• Robert F. McCauley

  • Role: Lead Counsel
  • Firm: Perkins Coie LLP, Palo Alto, California
  • Experience Note: Robert McCauley is a partner in Perkins Coie's Intellectual Property practice, focusing on patent litigation, post-grant proceedings, and strategic intellectual property counseling. His experience includes representing clients in complex patent disputes across various technologies, particularly in the semiconductor and software industries.

• Arpita Bhattacharyya

  • Role: Lead Counsel
  • Firm: Perkins Coie LLP, Palo Alto, California
  • Experience Note: Arpita Bhattacharyya is an associate in Perkins Coie's Intellectual Property practice, concentrating on patent litigation and other intellectual property matters. She has experience representing technology companies in district court litigation and before the Patent Trial and Appeal Board (PTAB).

Filings indicate that the case is currently stayed pending Inter Partes Review (IPR) institution decisions related to the patents at issue, including U.S. Patent No. 9,448,367.