PTAB

IPR2026-00123

Eoptolink Technology USA Inc v. Applied Optoelectronics Inc

Key Events

Petition

Title: Stepped-Profile Substrate for Optical Subassemblies
Brief Description: The ’887 patent discloses a substrate, such as a printed circuit board, with a stepped profile designed to improve the mounting and alignment of transmitter optical subassembly (TOSA) modules. The design purports to reduce the vertical offset between a TOSA and radio frequency (RF) terminals on the substrate, enabling shorter electrical interconnects to enhance signal performance at high transmission speeds.

Prior Art Relied Upon: Kuhara (Patent 7,366,367).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Kuhara discloses every limitation of claims 1-3. Kuhara’s optical data link includes a circuit board (the “substrate”) with a first mounting section for an optical module and a second for an electron device, separated by a step, which forms the claimed “stepped profile.” Petitioner mapped Kuhara’s first mounting section to the claimed “optical coupling end” and its interface part to the “electrical coupling end.” The step creates a “recessed TOSA mounting surface” (bottom face 29d) that is vertically offset from the component mounting surface. A vertical “positioning face 29a” in Kuhara allegedly functions as the claimed “mechanical stop” to engage and limit the travel of the edge-mounted TOSA module. Dependent claims 2 and 3, which add details about the TOSA module’s body and its vertical offset, were also argued to be expressly or inherently disclosed in Kuhara’s figures and description.

Prior Art Relied Upon: Kuhara (Patent 7,366,367).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner contended that even if not anticipatory, Kuhara renders the claims obvious. For claim 8, which requires a “plurality of TOSA modules,” Petitioner pointed to a separate embodiment in Kuhara (optical data link 2) that discloses a component with two semiconductor lasers, which a person of ordinary skill in the art (POSITA) would understand could function as two TOSA modules. For claims 10 and 12, directed to an “optical transceiver,” Petitioner argued Kuhara’s optical data link 2, which includes both a transmitter (TOSA) and a receiver (ROSA), is a transceiver. The specific substrate limitations of claim 10 were mapped to Kuhara’s transceiver embodiment in the same manner as described in Ground 1.
- Motivation to Combine (within the reference): A POSITA would be motivated to modify Kuhara’s single-TOSA embodiment in view of its dual-laser embodiment to create a multi-channel transmitter, a well-known strategy for achieving higher data transmission rates.
- Expectation of Success: Given that Kuhara describes both single and multi-module configurations in detail, a POSITA would have had a high expectation of success in implementing the claimed features.

Prior Art Relied Upon: Ho (Patent 10,509,184) and Kuhara (Patent 7,366,367).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Ho discloses a multi-channel optical transceiver system that includes a multi-channel TOSA arrangement with a plurality of TOSA modules and a multi-channel ROSA, thus teaching the high-level system claimed. While Ho teaches the overall architecture, Kuhara supplies the specific substrate implementation. Petitioner asserted that a POSITA would implement Ho’s advanced multi-channel transceiver using a substrate with the structural features taught by Kuhara, including the stepped profile, recessed mounting surface, and mechanical stop. The combination of Ho’s system and Kuhara’s substrate was alleged to meet all limitations of claims 8-12.
- Motivation to Combine: A POSITA designing an improved transceiver as taught by Ho would consult prior art like Kuhara to find solutions for component mounting and alignment. A POSITA would combine the teachings to leverage Kuhara’s disclosed benefits—better alignment, reduced size, and shorter wiring lengths—within Ho’s multi-channel system.
- Expectation of Success: The combination involved applying a known substrate design (Kuhara) to a known transceiver architecture (Ho). As both references disclose conventional components used for their intended purposes, a POSITA would have reasonably expected success through routine optimization.

Petitioner stipulated that if the Board institutes this inter partes review (IPR), it will not pursue in a parallel district court action any invalidity challenges under 35 U.S.C. §102 or §103 that were raised or reasonably could have been raised in this petition. This stipulation was presented to argue against a discretionary denial under the Fintiv factors by mitigating concerns about parallel proceedings and inefficient use of resources.

Petitioner requests institution of an IPR and cancellation of claims 1-3 and 8-12 of the ’887 patent as unpatentable.