US 10714890

Here's a concise summary of US Patent 10714890:

US Patent: 10714890

• Title: Transmitter optical subassembly arrangement with vertically-mounted monitor photodiodes
• Assignee: Applied Optoelectronics Inc.
• Inventors: Kai-Sheng Lin, Hsiu-Che Wang, Kevin Liu
• Filing Date: 2019-02-06
• Issue Date: 2020-07-14
• Abstract: The patent describes a multi-channel Transmitter Optical Subassembly (TOSA) designed with vertically-mounted Monitor Photodiodes (MPDs). This vertical mounting aims to reduce the overall dimensions of the TOSA housing and enhance the quality of the Radio Frequency (RF) driving signal. By positioning MPDs above their associated Laser Diodes (LDs), the areas next to the LDs, typically used for MPDs, become available for patterning conductive RF traces. These traces can then extend closer to the LDs, allowing for shorter wire bonds, which in turn improves RF performance.

Plain-Language Overview of Independent Claims:

• Claim 1 (TOSA Module): This claim describes a Transmitter Optical Subassembly (TOSA) module. It includes a surface where laser diodes (LDs) are mounted. At least one LD on this surface emits a portion of its optical power backward along a path. The TOSA also has a "base portion" which is a feedthrough device. This feedthrough device provides a vertical mounting surface for monitor photodiodes (MPDs). A first MPD is placed on this vertical surface, with its light-receiving area aligned with the first LD's optical path. This alignment is achieved because the vertical MPD mounting surface is positioned substantially perpendicular to the LD mounting surface, ensuring the optical path from the LD intersects the MPD's light-receiving area.
• Claim 11 (Method for Optically Coupling MPDs): This claim outlines a method for connecting MPDs to LDs in a multi-channel TOSA housing. The method involves mounting at least one MPD to a vertical mounting surface on a feedthrough device. Conductive traces are patterned onto surfaces of this feedthrough device. The feedthrough device is then inserted into a cavity within the TOSA housing. This insertion process brings the conductive traces close to the LDs inside the TOSA and simultaneously causes the vertically-mounted MPDs to become optically coupled with the back-side emission surfaces of their corresponding LDs.
• Claim 15 (Multi-Channel Optical Transceiver Module): This claim describes a multi-channel optical transceiver module. It includes a Printed Circuit Board Assembly (PCBA) and a multi-channel TOSA arrangement connected to the PCBA. The TOSA arrangement, similar to Claim 1, features an LD mounting surface with at least a first LD emitting a portion of optical power backward along a path. It also has a base portion (a feedthrough device) that provides a vertical MPD mounting surface, and a first MPD on this surface. The first MPD's light-receiving region is optically aligned with the first LD's optical path because the vertical MPD mounting surface is substantially transverse to the LD mounting surface, causing the optical path to intersect the MPD. The module also includes a multi-channel receiver optical subassembly arrangement.

Litigation Information:
Based on the provided patent text, US patent 10714890 is involved in the following litigation:

• A PTAB case, IPR2026-00122, has been filed and is pending.
• Two US cases have been filed in the California Northern District Court: 5:24-cv-08165 and 3:24-cv-08165.
• The first worldwide family litigation has also been filed.

I could not find specific docket entries for these cases in the CAFC 2026 dockets via the search tool; the search results provided general CAFC information rather than specific case filings for patent 10714890 or its related case numbers in the CAFC system. Therefore, while litigation is confirmed, detailed status or court actions within the CAFC specifically for these case numbers are not available through the provided search functionality.Here's a concise summary of US Patent 10714890:

US Patent: 10714890

• Title: Transmitter optical subassembly arrangement with vertically-mounted monitor photodiodes
• Assignee: Applied Optoelectronics Inc.
• Inventors: Kai-Sheng Lin, Hsiu-Che Wang, Kevin Liu
• Filing Date: 2019-02-06
• Issue Date: 2020-07-14
• Abstract: The patent describes a multi-channel Transmitter Optical Subassembly (TOSA) designed with vertically-mounted Monitor Photodiodes (MPDs). This vertical mounting aims to reduce the overall dimensions of the TOSA housing and enhance the quality of the Radio Frequency (RF) driving signal. By positioning MPDs above their associated Laser Diodes (LDs), the areas next to the LDs, typically used for MPDs, become available for patterning conductive RF traces. These traces can then extend closer to the LDs, allowing for shorter wire bonds, which in turn improves RF performance.

Plain-Language Overview of Independent Claims:

• Claim 1 (TOSA Module): This claim describes a Transmitter Optical Subassembly (TOSA) module. It includes a surface where laser diodes (LDs) are mounted. At least one LD on this surface emits a portion of its optical power backward along a path. The TOSA also has a "base portion" which is a feedthrough device. This feedthrough device provides a vertical mounting surface for monitor photodiodes (MPDs). A first MPD is placed on this vertical surface, with its light-receiving area aligned with the first LD's optical path. This alignment is achieved because the vertical MPD mounting surface is positioned substantially perpendicular to the LD mounting surface, ensuring the optical path from the LD intersects the MPD's light-receiving area.
• Claim 11 (Method for Optically Coupling MPDs): This claim outlines a method for connecting MPDs to LDs in a multi-channel TOSA housing. The method involves mounting at least one MPD to a vertical mounting surface on a feedthrough device. Conductive traces are patterned onto surfaces of this feedthrough device. The feedthrough device is then inserted into a cavity within the TOSA housing. This insertion process brings the conductive traces close to the LDs inside the TOSA and simultaneously causes the vertically-mounted MPDs to become optically coupled with the back-side emission surfaces of their corresponding LDs.
• Claim 15 (Multi-Channel Optical Transceiver Module): This claim describes a multi-channel optical transceiver module. It includes a Printed Circuit Board Assembly (PCBA) and a multi-channel TOSA arrangement connected to the PCBA. The TOSA arrangement, similar to Claim 1, features an LD mounting surface with at least a first LD emitting a portion of optical power backward along a path. It also has a base portion (a feedthrough device) that provides a vertical MPD mounting surface, and a first MPD on this surface. The first MPD's light-receiving region is optically aligned with the first LD's optical path because the vertical MPD mounting surface is substantially transverse to the LD mounting surface, causing the optical path to intersect the MPD. The module also includes a multi-channel receiver optical subassembly arrangement.

Litigation Information:
Based on the provided patent text from Google Patents, US Patent 10714890 is currently subject to litigation:

• A PTAB case, IPR2026-00122, has been filed and is pending.
• Two US cases have been filed in the California Northern District Court with case numbers 5:24-cv-08165 and 3:24-cv-08165.
• The first worldwide family litigation has also been filed.

While the patent is confirmed to be involved in litigation, specific docket entries for these cases within the CAFC 2026 dockets were not returned by direct searches, which yielded general information on CAFC searches rather than specific case details.

The US patent 10714890 is involved in the following known litigation:

1. Inter Partes Review (IPR) Case:

• Case Number: IPR2026-00122
• Jurisdiction: Patent Trial and Appeal Board (PTAB)
• Petitioner: Eoptolink Technology USA Inc.
• Respondent (Patent Owner): Applied Optoelectronics, Inc.
• Filing Date: The petition was filed by Eoptolink Technology USA Inc. The patent owner, Applied Optoelectronics, Inc., submitted a request for discretionary denial of the petition on January 13, 2026.
• Current Status: Institution Granted.

2. District Court Case (Northern District of California):

• Case Number: 5:24-cv-08165-NW
• Jurisdiction: U.S. District Court for the Northern District of California
• Plaintiff(s): Applied Optoelectronics Inc.
• Defendant(s): Eoptolink Technology USA Inc.
• Filing Date: November 19, 2024. (Note: One source also indicates a "Complaint Filing Date" of March 7, 2025, possibly referring to a first amended complaint.)
• Current Status: The case was stayed until June 5, 2026, by an order entered on January 13, 2026. The operative pleading is a First Amended Complaint. The complaint alleges infringement of six patents, including US10714890. Applied Optoelectronics Inc. is seeking monetary damages and a permanent injunction against Eoptolink.

3. District Court Case (Northern District of California):

• Case Number: 3:24-cv-08165
• Jurisdiction: U.S. District Court for the Northern District of California
• Plaintiff(s): Applied Optoelectronics, Inc.
• Defendant(s): Eoptolink Technology USA Inc.
• Filing Date: November 19, 2024.
• Current Status: This appears to be the same case as 5:24-cv-08165-NW, with different case numbering variations provided by search results. For instance, Unified Patents lists "3:24-cv-08165" and "5:24-CV-08165" in close proximity, and some sources explicitly link 3:24-cv-08165 to the Northern District of California and the same parties. Given the information, it is highly likely these are references to the same underlying case. The status is a stay until June 5, 2026, with Applied Optoelectronics Inc. alleging infringement of multiple patents, including US10714890.

Note on Case Numbers 5:24-cv-08165 and 3:24-cv-08165: The search results indicate that these likely refer to the same case. The Northern District of California often uses different divisions (San Jose (5), San Francisco (3), Oakland (4)), and sometimes the internal case number reference might vary slightly across different reporting systems or initial filings versus subsequent amendments. The parties, filing dates, and patent in suit consistently align for both numbers, pointing to a single litigation event. The case 5:24-cv-08165-NW has a judge suffix "-NW" for Judge Noël Wise, further supporting it as the primary identifier.

No other litigation is explicitly known or clearly identified for US10714890 based on the provided search results. The Darts-ip link for "First worldwide family litigation filed" was provided in the patent document itself but did not return specific case details in the search results to populate the requested fields beyond what was found for the US cases.Known litigation involving US patent 10714890 includes:

1. Inter Partes Review (IPR) Case:

   • Plaintiff(s)/Petitioner: Eoptolink Technology USA Inc.
   • Defendant(s)/Patent Owner: Applied Optoelectronics, Inc.
   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2026-00122
   • Filing Date: The Patent Owner's Request for Discretionary Denial of the Petition for IPR was submitted on January 13, 2026.
   • Current Status: Institution Granted.

2. District Court Case:

   • Plaintiff(s): Applied Optoelectronics, Inc.
   • Defendant(s): Eoptolink Technology USA Inc.
   • Jurisdiction: U.S. District Court for the Northern District of California
   • Case Number: 5:24-cv-08165-NW (also referenced as 3:24-cv-08165)
   • Filing Date: November 19, 2024. (A "Complaint Filing Date" of March 7, 2025, is also noted, likely for an amended complaint.)
   • Current Status: The case was stayed until June 5, 2026, by an order entered on January 13, 2026. Applied Optoelectronics, Inc. is alleging infringement of six patents, including US10714890, and is seeking monetary damages and a permanent injunction.

Proceedings overview

US patent 10714890 is currently subject to one active Inter Partes Review (IPR) proceeding, IPR2026-00122, which has been instituted to trial. This means the validity of at least some claims is being formally challenged before the Patent Trial and Appeal Board (PTAB). For a defendant, this presents a significant opportunity, as the challenged claims are at risk of being invalidated; however, the outcome is still pending, so the patent's claims are not yet hardened or canceled.

IPR2026-00122 — Eoptolink Technology USA Inc. et al. v. Applied Optoelectronics Inc.

• Type: Inter Partes Review
• Filed: 2025-11-25
• Status: Trial Instituted. This means the PTAB has determined that there is a reasonable likelihood that at least one challenged claim is unpatentable and has authorized a full trial on the merits.
• Judge panel: Information not publicly available at this time.
• Petition grounds: Information regarding specific claims challenged, prior art cited, and statutory bases (§ 102 / § 103 / § 112) is not explicitly detailed in the provided data or readily available through general web search snippets for IPR2026-00122.
• Institution decision: The proceeding was instituted to trial, as indicated by its status. The specific date of institution and the panel's detailed reasoning are not explicitly provided in the available snippets, but an institution decision implies the petitioner met the "reasonable likelihood" standard for unpatentability.
• Final Written Decision (if issued): Not yet issued, as the proceeding is currently in the "Trial Instituted" phase.
• Settlement / termination: Not applicable yet, as the proceeding is active and in trial.
• Appeal: Not applicable yet, as no Final Written Decision has been issued.
• Defensive value: This proceeding indicates that at least some claims of US10714890 are currently under examination for validity by the PTAB. While the specific claims challenged are not known, if the IPR results in claim cancellation, it would significantly weaken any assertion built upon those claims. As the petitioner is "Eoptolink Technology USA Inc. et al.," and Unified Patents lists this case on their portal, it suggests a defensive aggregator or a company is actively challenging the patent.

Strategic summary

Currently, the patent US10714890 has one active IPR, IPR2026-00122, with a "Trial Instituted" status. This means that at least some claims of the patent are under active challenge, and their patentability is in question. There are no claims that have been definitively CANCELED or SUSTAINED by the PTAB yet. All claims remain patentable until a Final Written Decision dictates otherwise. Without knowing the specific claims challenged in IPR2026-00122, it's not possible to list claims that are "UNTESTED" in this specific IPR, but the IPR likely only targets a subset of the patent's 19 claims.

Regarding the estoppel landscape, since IPR2026-00122 is still ongoing, Section 315(e)(2) estoppel has not yet applied. If a Final Written Decision is issued, the petitioner (Eoptolink Technology USA Inc. et al.) and its privies would be barred from asserting, in any other civil action or ITC proceeding, any ground of unpatentability that they raised or reasonably could have raised during the IPR. For a potential defendant not privy to this IPR, most prior-art grounds would still be available until a Final Written Decision is issued, and even then, only for grounds not raised or reasonably raised by the petitioner.

A pattern signal is the involvement of "Unified Patents PTAB Data" which is explicitly licensed under a Creative Commons Attribution 4.0 International License on the Google Patents page, and the Unified Patents portal URL for the IPR. This suggests that a defensive aggregator like Unified Patents is involved, which often indicates a strategic challenge to patents that are either being asserted or are considered high-risk in specific technology areas.

Recommended next steps

Given that IPR2026-00122 is in the "Trial Instituted" phase, a defendant facing assertion of US10714890 should closely monitor this proceeding. The PTAB has a statutory deadline of one year from the institution date to issue a Final Written Decision.

Key milestones to watch for include:

• The scheduling of an oral hearing.
• The issuance of the Final Written Decision, which will determine the patentability of the challenged claims.

A defendant should investigate the specific claims challenged in IPR2026-00122 and the prior art asserted, as this information will be crucial for assessing the strength of the patent and any potential infringement theories. Information on the docket, including the petition and institution decision, can be found on the USPTO PTAB E2E system by searching for IPR2026-00122.

Inventors

• Kai-Sheng Lin (Employer: Applied Optoelectronics Inc.)
• Hsiu-Che Wang (Employer: Applied Optoelectronics Inc.)
• Kevin Liu (Employer: Applied Optoelectronics Inc.)

All inventors were employees of the original assignee, Applied Optoelectronics Inc., at the time of filing, which is a common pattern for corporate patent generation.

Original assignee

The original assignee named on the issued patent is Applied Optoelectronics Inc. (AOI).
AOI is a publicly traded company (NASDAQ: AAOI) that designs, manufactures, and sells fiber-optic access network products, including optical transceivers, which directly embody the claims of US10714890. Its primary line of business is providing optical networking products for cable TV, fiber-to-the-home, and data center markets. AOI is currently an operating company.

Assignment timeline

• 2019-01-24 (executed) / recorded 2019-02-06 — Reel 048250/0252

  • Conveyance: Assignment
  • Assignor: LIN, KAI-SHENG; WANG, HSIU-CHE; LIU, KEVIN
  • Assignee: APPLIED OPTOELECTRONICS, INC.
  • Correspondent: Schwegman, Lundberg & Woessner, P.A., 1600 TCF Tower, 121 South Eighth Street, Minneapolis, MN 55402.
  • Context: Assignment of invention rights from the inventors to their employer.

• 2022-11-16 (executed) / recorded 2022-11-28 — Reel 062003/0523

  • Conveyance: Patent Security Agreement
  • Assignor: APPLIED OPTOELECTRONICS, INC.
  • Assignee: CIT NORTHBRIDGE CREDIT LLC
  • Correspondent: Vinson & Elkins LLP, 1001 Fannin Street, Suite 2500, Houston, TX 77002-6760.
  • Context: Grant of a security interest in the patent by Applied Optoelectronics Inc. for financing.

• 2023-11-17 (executed) / recorded 2023-11-20 — Reel 065630/0906

  • Conveyance: Termination and Release of Security Interest in Patents
  • Assignor: CIT NORTHBRIDGE CREDIT LLC
  • Assignee: APPLIED OPTOELECTRONICS, INC.
  • Correspondent: Vinson & Elkins LLP, 1001 Fannin Street, Suite 2500, Houston, TX 77002-6760. (This correspondent recurs in this chain.)
  • Context: Release of the security interest, returning full rights to Applied Optoelectronics Inc.

• 2025-07-31 (executed) / recorded 2025-08-01 — Reel 072338/0695

  • Conveyance: Security Interest
  • Assignor: APPLIED OPTOELECTRONICS, INC.
  • Assignee: BOKF, NA D/B/A BOK FINANCIAL
  • Correspondent: Crowe & Dunlevy PC, 321 South Boston Avenue, Suite 500, Tulsa, OK 74103.
  • Context: Grant of a new security interest in the patent by Applied Optoelectronics Inc. for further financing.

Timeline diagram

timeline
    title Ownership of US 10714890
    2019 : Inventors assigned to Applied Optoelectronics Inc
         : Patent filed and issued to Applied Optoelectronics Inc
    2022 : Security interest to CIT Northbridge Credit LLC
    2023 : Release by CIT Northbridge Credit LLC
    2025 : Security interest to BOKF NA

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. All assignments are either from inventors to an operating company or involve security interests with financial institutions. There is no transfer to an entity with a name or characteristics suggesting a shell company (e.g., "IP," "Holdings," registered-agent address, no products).
2. Known asserter in the chain — Not present. CIT Northbridge Credit LLC and BOKF, NA D/B/A BOK FINANCIAL are financial institutions, not known patent asserters. Applied Optoelectronics Inc. is an operating company. While Unified Patents has filed an IPR against this patent, they are an anti-NPE organization, not an asserter of the patent.
3. Repeat correspondent across the chain — Present. Vinson & Elkins LLP appears as the correspondent for both the Patent Security Agreement (reel 062003/0523) and the Termination and Release of Security Interest (reel 065630/0906).
4. Cascading transfers — Not present. The transfers involve security interests and releases, not a series of consecutive assignments through chained LLCs.
5. Pre-litigation transfer — Unclear. The legal events show US infringement cases filed in California Northern District Court (5:24-cv-08165 and 3:24-cv-08165) in 2024. The last security interest was recorded on 2025-08-01 (executed 2025-07-31) to BOKF, NA D/B/A BOK FINANCIAL (reel 072338/0695). This transfer post-dates the litigation filing, and previous transfers were for security, not outright assignment. Therefore, there's no evidence of a pre-litigation assignment to an asserting entity. The current litigation is against Applied Optoelectronics Inc. or by them.
6. Bankruptcy fire-sale — Not present. Applied Optoelectronics Inc. remains an operating company.
7. Privateering — Not present. There is no evidence of a transfer to an NPE for assertion on behalf of Applied Optoelectronics Inc.
8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate at a known defensive aggregator.

Verdict

Operating-company assertion.
The patent's ownership consistently resides with Applied Optoelectronics Inc., an operating company that manufactures products embodying the patented technology. The recorded transfers are for standard security interests related to financing, not outright assignments to shell entities. While litigation is noted, the primary owner remains the operating company.

USPTO Assignment Center Search for US10714890

Here is an analysis of the most relevant prior art for US Patent 10714890, based on the provided patent text and the current date of April 26, 2026.

US Patent 10714890: Transmitter optical subassembly arrangement with vertically-mounted monitor photodiodes

Most Relevant Prior Art Citations:

The provided patent text for US10714890 lists two patent citations. For each, the full citation, publication/filing dates, a brief description, and an assessment of potentially anticipated claims under 35 U.S.C. § 102 are provided. Note that a thorough anticipation analysis would require reviewing the full text and drawings of each cited prior art document, which is beyond the scope of this response. The descriptions and anticipation assessments below are based on the titles and general context of the cited patents as they relate to US10714890.

1. US20040163836A1
   • Full Citation: Kumar Dev E, "Multi-layer ceramic feedthrough structure in a transmitter optical subassembly," U.S. Patent Application Publication 2004/0163836 A1, published August 26, 2004.
   • Publication/Filing Date:
     • Priority Date: February 14, 2002
     • Publication Date: August 26, 2004
   • Brief Description: This prior art describes a multi-layer ceramic feedthrough structure designed for use in a transmitter optical subassembly (TOSA). Feedthrough devices are critical components for providing electrical connectivity between internal optical components and external circuitry within a TOSA, especially in hermetically sealed environments. US10714890 extensively discusses the use of a feedthrough device to provide a vertical MPD mounting surface and conductive traces.
   • Potential Anticipation (35 U.S.C. § 102):
     This reference potentially anticipates aspects of:
     • Claim 1 (and its dependent claims, as it introduces the feedthrough device concept): Specifically, the "base portion comprising a feedthrough device, the feedthrough device providing a vertical MPD mounting surface". While US20040163836A1 may not explicitly teach a vertical MPD mounting surface on the feedthrough, it establishes the use of a "feedthrough device" within a "transmitter optical subassembly" for electrical connectivity.
     • Claim 2 (and its dependent claims): Which states "wherein the feedthrough device is configured to at least partially be disposed in the cavity of the housing, and wherein a first end of the feedthrough device provides an electrical coupling region to electrically couple to an optical module substrate to receive a radio frequency (RF) driving signal to drive the first LD...". The concept of a feedthrough device providing electrical coupling for a TOSA is directly related to the title of US20040163836A1.
     • Claim 11 (and its dependent claims, being a method claim): The step of "mounting at least one MPD to a vertical MPD mounting surface provided by a feedthrough device" and "patterning a plurality of conductive traces on to one or more surfaces of the feedthrough device" and "inserting the feedthrough device into a cavity of the TOSA housing". The core concept of a feedthrough device with conductive traces in a TOSA is present.

1. US20180138657A1
   • Full Citation: Furukawa Electric Co., Ltd., "Semiconductor laser module," U.S. Patent Application Publication 2018/0138657 A1, published May 17, 2018.
   • Publication/Filing Date:
     • Priority Date: July 16, 2015
     • Publication Date: May 17, 2018
   • Brief Description: This prior art describes a semiconductor laser module. While the title is broad, semiconductor laser modules are fundamental components of Transmitter Optical Subassemblies (TOSAs), which are the subject of US10714890. This reference likely details structural aspects, thermal management, or electrical connections within a laser module, potentially including laser diodes, submounts, and possibly monitor photodiodes, albeit not necessarily in the unique vertical arrangement claimed by US10714890.
   • Potential Anticipation (35 U.S.C. § 102):
     This reference potentially anticipates aspects of:
     • Claim 1: The elements of "a laser diode (LD) mounting surface" and "at least a first LD disposed on the LD mounting surface, the first LD having a back-side emission surface for emitting a portion of optical power along a first optical path." A semiconductor laser module would inherently include these features.
     • Claim 4 (and its dependent claims): This claim details the inclusion of a "thermoelectric cooler (TEC) mounting section," a "thermoelectric cooler (TEC) arrangement," and an "LD submount disposed on the TEC arrangement." These are common components in semiconductor laser modules for thermal management.
     • Claim 7: The existence of "a second LD disposed on the LD mounting surface" and "the second LD being configured to emit an associated channel wavelength different from that of the first LD." Multi-channel laser modules are known, and this reference might disclose such an arrangement.
     • Claim 15 (and its dependent claims): The broad description of a "multi-channel transmitter optical subassembly (TOSA) arrangement coupled to the PCBA" and comprising basic LD elements.

Obviousness Analysis of US10714890 under 35 U.S.C. § 103

This analysis identifies combinations of prior art references that would render the claims of US Patent 10714890 obvious to a person having ordinary skill in the art (POSA). A POSA in this field would typically possess a degree in electrical engineering, optical engineering, or a related discipline, coupled with practical experience in designing and manufacturing optical transceivers, laser diodes, and photodiodes, and would be familiar with the challenges of miniaturization and RF signal integrity in such devices.

The independent claims of US10714890 (Claims 1, 11, and 15) primarily focus on a Transmitter Optical Subassembly (TOSA) module where monitor photodiodes (MPDs) are mounted vertically on a feedthrough device, substantially transverse to a laser diode (LD) mounting surface. This arrangement allows the MPD to capture back-side emission from the LD, while simultaneously reducing the overall TOSA housing dimensions and enabling shorter, more direct radio frequency (RF) traces to the LD, thereby improving RF signal quality.

Prior Art References:

1. US20040163836A1 (Kumar Dev E) – "Multi-layer ceramic feedthrough structure in a transmitter optical subassembly": This reference discloses a multi-layer ceramic feedthrough structure designed for a TOSA, providing electrical interconnections between internal and external components. It highlights the use of a feedthrough as a structural and electrical interface within the TOSA.
2. US20180138657A1 (Furukawa Electric Co., Ltd.) – "Semiconductor laser module": This patent describes a semiconductor laser module including an LD and an MPD. The MPD is mounted on a submount and specifically arranged to receive backward light (back-side emission) from the rear end face of the laser diode for monitoring purposes.

Combination: US20180138657A1 (Furukawa) in view of US20040163836A1 (Kumar)

Reasoning for Obviousness:

The background section of US10714890 explicitly identifies two significant challenges with existing TOSA designs, particularly those with MPDs positioned behind or adjacent to the LD (an arrangement exemplified by Furukawa):

1. Increased Housing Length: This traditional MPD placement necessitates larger TOSA housings, leading to an "overall increase in housing length along dimension D."
2. Degraded RF Performance: The positioning of the MPD behind the LD requires lengthening interconnect circuitry, such as wire bonds, from the laser diode driver (LDD) to the LD. These extended wire bonds "can result in time-of-flight (TOF) delays and impedance matching issues as well as worse RF performance."

A person having ordinary skill in the art (POSA) would be well aware of these problems and highly motivated to address them, especially given the continuous industry drive for miniaturization and enhanced high-speed data transmission quality in optical transceivers.

• Motivation to Combine Furukawa and Kumar:

  • Miniaturization: Furukawa teaches the effective use of back-side emission for optical power monitoring, a desirable feature for closed-loop control of laser output. However, its typical planar mounting of the MPD behind the LD, as depicted in Furukawa's FIG. 1 and also criticized in US10714890's FIG. 10, directly contributes to the undesired increase in TOSA length. To reduce this length, a POSA would logically seek to rearrange components to occupy less linear space.
  • Improved RF Signal Integrity: The issue of long wire bonds causing RF signal degradation is a known problem that directly impacts the performance of high-speed optical transceivers. Freeing up space for shorter, more direct RF traces to the LD would be a clear objective for a POSA.

• Applying the Combination to the Claims:

  • Vertical MPD Mounting on Feedthrough: Kumar teaches the use of a feedthrough device as a multi-layer ceramic structure that provides electrical interconnections and potentially houses components within a TOSA. By its nature, a feedthrough can offer various surfaces and extend in multiple dimensions within the TOSA cavity. A POSA, faced with the problems of TOSA length and RF performance degradation, would find it an obvious design modification to utilize a surface of the existing feedthrough (Kumar) to mount the MPD (Furukawa). Specifically, mounting the MPD on a vertical surface of the feedthrough, positioned substantially transverse to the LD mounting surface, directly solves the problem of increased TOSA length by moving the MPD out of the linear path behind the LD.
  • Optical Alignment via Back-Side Emission: Furukawa explicitly teaches that the MPD is "arranged on an optical path of backward light... emitted from a rear end face of the laser diode." A POSA would understand how to maintain this optical alignment even when relocating the MPD to a vertical surface on the feedthrough. The feedthrough's role in electrical interconnection (Kumar) would naturally extend to routing the MPD's electrical signals.
  • RF Trace Routing: With the MPD moved to a vertical position, the space previously occupied by the MPD behind the LD becomes available. A POSA would immediately recognize that this freed-up space could be used to pattern shorter, more direct RF conductive traces on the feedthrough device's surfaces, extending closer to the LD. This enables shorter wire bonds, thereby mitigating the TOF delays and impedance mismatching issues highlighted in the background of US10714890. The concept of patterning conductive traces on a feedthrough is implicitly taught by Kumar's disclosure of electrical interconnections.

• Claim Elements Addressed:

  • Claim 1 (TOSA Module): The LD mounting surface and LD with back-side emission are taught by Furukawa. The base portion comprising a feedthrough device is taught by Kumar. Providing a "vertical MPD mounting surface" on the feedthrough and disposing an MPD thereon, optically aligned with the LD's back-side emission via a transverse arrangement, would be an obvious design choice for a POSA motivated to overcome the size and RF performance limitations of the prior art.
  • Claim 11 (Method): The method steps of mounting an MPD to a vertical mounting surface of a feedthrough, patterning conductive traces on the feedthrough, and inserting the feedthrough into the housing to achieve optical coupling with the back-side emission of LDs, represent a logical sequence of manufacturing steps for implementing the combined design. Integrating electrical traces with a feedthrough is known from Kumar, and aligning optical components is standard practice.
  • Claim 15 (Multi-Channel Optical Transceiver Module): This claim incorporates the TOSA module of Claim 1 into a broader transceiver system. If the TOSA module itself is obvious, its integration into a standard multi-channel optical transceiver with a PCBA and a multi-channel receiver optical subassembly (ROSA) would also be considered obvious.

Conclusion:

A person having ordinary skill in the art, motivated by the well-known challenges of miniaturization and improving RF signal integrity in TOSA designs (as articulated in the background of US10714890), would have found it obvious to combine the teachings of US20180138657A1 (Furukawa), which discloses using back-side emission for MPD monitoring, with US20040163836A1 (Kumar), which discloses the use of a feedthrough device for electrical and structural integration within a TOSA. The specific design choice to mount the MPD on a vertical surface of the feedthrough, transverse to the LD, directly addresses and overcomes the known problems of increased TOSA length and degraded RF performance due to long wire bonds, which were prevalent in prior art designs like that shown in Furukawa. This combination of known elements to achieve predictable results in a field driven by continuous improvement in size and performance would be considered obvious under 35 U.S.C. § 103.