Soto v. USPTO: Federal Circuit Affirms Optical LAN Patent Unpatentable (604 Days)
Alexander I. Soto and Walter G. Soto challenged the USPTO’s rejection of their optical local area network communication patent (US20210143913A1) before the Federal Circuit. The court affirmed the unpatentability finding in a Rule 36 judgment — issuing no written opinion — closing the appeal after 604 days.
Federal Circuit summarily affirms optical LAN patent rejection
Inventors Alexander I. Soto and Walter G. Soto filed an appeal (Case No. 23-2008) with the United States Court of Appeals for the Federal Circuit on 13 June 2023, challenging the USPTO’s determination that their patent application US20210143913A1 — covering a communication system and method for an optical local area network — was unpatentable. The defendants in the appeal were represented by the Acting Under Secretary of Commerce for Intellectual Property and Acting Director of the USPTO, Derrick Brent. Plaintiffs were represented by Laurence & Phillips IP Law.
The Federal Circuit closed the case on 6 February 2025, issuing an affirmance under Federal Circuit Rule 36. A Rule 36 judgment is a one-line order — ‘AFFIRMED’ — issued without an accompanying written opinion. This procedural mechanism signals that the appellate panel found the lower tribunal’s decision free from reversible error and that a written explanation would add no new legal value. The basis of termination is recorded as ‘Unpatentable,’ confirming that the USPTO’s rejection of the application survives the appellate challenge intact.
The 604-day duration is broadly consistent with Federal Circuit appeal timelines in ex parte patent prosecution matters. A Rule 36 affirmance is particularly notable for what it withholds: because no written opinion was issued, the decision creates no binding precedent and provides the inventors with minimal guidance on which specific grounds of rejection were dispositive. The public record does not disclose whether further options such as a petition for rehearing or certiorari to the Supreme Court were considered, nor does it reveal the precise PTAB grounds affirmed.
Filing to Unpatentable in 604 days
604 days from filing to Federal Circuit affirmance — consistent with typical PTAB appeal timelines
Federal Circuit affirms: what the Rule 36 ruling means for both parties
Rule 36 affirmance: no opinion, no reversible error
A Federal Circuit Rule 36 judgment affirms the decision below with a single word — ‘AFFIRMED’ — and no written reasoning. The panel is signalling it found no reversible error in the PTAB or USPTO’s unpatentability determination. Because no opinion accompanies it, the ruling carries no precedential weight for third parties but is conclusive for the parties in this case.
Procedural affirmanceApplication definitively rejected; patent will not issue
For Alexander and Walter Soto, the affirmance is a terminal outcome on this application. The USPTO’s unpatentability finding has been upheld at the highest level below the Supreme Court. The optical LAN communication system and method described in US20210143913A1 will not proceed to grant in its current form. Continuation or continuation-in-part strategies, if viable, would require filing new claims not barred by prior art already of record.
Application rejected — no patent issuedUSPTO’s rejection fully vindicated on appeal
The USPTO and its acting director prevail: the agency’s determination that the Soto optical LAN application failed to meet patentability requirements is now affirmed by the Federal Circuit. This outcome is consistent with the historically high affirmance rate the USPTO enjoys in ex parte appeals before the Federal Circuit. The Sotos’ appellate options at this level are exhausted; the only remaining avenue would be a petition for certiorari to the Supreme Court, which is rarely granted in patent prosecution matters.
USPTO rejection upheldOptical LAN IP landscape: one fewer blocking application
For companies developing or deploying optical local area network technologies, this outcome removes US20210143913A1 as a pending threat. Because no patent issued, there is no granted claim set to design around or license. However, practitioners should note that the Rule 36 nature of the ruling offers no claim-construction guidance — any related continuation filings by the Sotos would need independent freedom-to-operate assessment. Competitors in the optical LAN space should monitor the application family for continuation activity.
No enforceable patent grantedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Alexander I. Soto | Individual | Inventors and applicants — holders of optical LAN communication patent application US20210143913A1Search in Eureka ↗ |
| Co-Plaintiff | Walter G. Soto | Individual | Search in Eureka ↗ |
| Defendant | DERRICK BRENT, Acting Under Secretary of Commerce for Intellectual Property and Acting Director of the United States Patent and Trademark Office | Individual | Acting Director of the USPTO, representing the agency’s patentability determination on appealSearch in Eureka ↗ |
| Plaintiff counsel | Derek Meeker | Attorney | Counsel for Alexander I. SotoSearch in Eureka ↗ |
| Plaintiff counsel | Kevin B. Laurence | Attorney | Counsel for Alexander I. SotoSearch in Eureka ↗ |
| Plaintiff counsel | Matthew C. Phillips | Attorney | Counsel for Alexander I. SotoSearch in Eureka ↗ |
| Plaintiff law firm | Laurence & Phillips IP Law | Law Firm | Representing Alexander I. SotoSearch in Eureka ↗ |
| Defendant counsel | Thomas W. Krause | Attorney | Counsel for DERRICK BRENT, Acting Under Secretary of Commerce for Intellectual Property and Acting Director of the United States Patent and Trademark OfficeSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The verdict reads: ‘THIS CAUSE having been heard and considered, it is ORDERED and ADJUDGED: AFFIRMED. See Fed. Cir. R. 36.’ A Rule 36 judgment is issued without a written opinion when the panel unanimously concludes the lower decision is correct under an applicable standard and that an opinion would lack precedential value. Applied here, it means the Federal Circuit reviewed the USPTO’s unpatentability determination under its applicable standard of review — typically substantial evidence for factual findings — and found no reversible error. The ruling is binding on the parties but cannot be cited as precedent by third parties in future proceedings.
US20210143913A1 — Optical Local Area Network Communication System
US20210143913A1 (application number US17/138794) is a patent application by Alexander I. Soto and Walter G. Soto covering a communication system and method for an optical local area network (optical LAN). Optical LAN technology uses fibre-optic infrastructure to replace traditional copper-based Ethernet within a building or campus environment, typically leveraging passive optical network architecture. The application was published on 13 May 2021 and proceeded through USPTO examination before being rejected as unpatentable — a determination the Federal Circuit has now affirmed.
Optical LAN communication systems sit at the intersection of enterprise networking, passive optical networking, and wavelength-division multiplexing — a strategically active patent space. The unpatentability of this application suggests the claimed system and method likely faced prior art challenges from the established body of passive optical LAN patents, including those held by major networking and telecommunications incumbents. For competitors and new entrants in enterprise optical networking, the failure of this application removes one potential blocking right — but the broader IP landscape in this domain remains dense and warrants continuous monitoring.
Should you run an FTO analysis against the US17/138794 application family?
For product teams and R&D leaders building or deploying optical local area network systems — including passive optical LAN, enterprise fibre distribution, or wavelength-division multiplexing equipment — the rejection of US20210143913A1 is a relevant data point. While this specific application will not proceed to grant, any continuation or divisional filings by the Soto inventors could introduce new claim sets targeting the same or adjacent technology. An FTO review of the full application family is advisable before finalising product architectures.
PatSnap Eureka’s FTO Search Agent can map the entire US17/138794 application family, identify related pending continuations, surface the prior art cited in the rejection record, and cross-reference live granted patents in the optical LAN and passive optical networking space. This gives R&D and legal teams a consolidated view of risk — including claims that may not yet be published — enabling faster, evidence-based design decisions before product launch.
Run a freedom-to-operate analysis on US20210143913A1 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit appeals: optical LAN and telecom patent patentability cases
Explore Federal Circuit ex parte appeals involving optical networking and telecommunications patents with comparable unpatentability outcomes and Rule 36 affirmances.
What this case signals for optical LAN and telecommunications IP strategy
A Rule 36 affirmance in an ex parte prosecution appeal is a clean but silent result — useful strategically even without written reasoning.
Rule 36 affirmances provide no claim-construction guidance — monitor continuations
Because the Federal Circuit issued no written opinion, practitioners cannot extract claim-scope reasoning. If the Soto family files continuation applications with amended claims, those will need fresh patentability and FTO analysis. Companies in the optical LAN space should set watches on the US17/138794 application family for any downstream activity.
High USPTO affirmance rate in ex parte appeals reinforces PTAB strategy importance
This outcome is consistent with the Federal Circuit’s historically high affirmance rate in ex parte prosecution appeals. IP teams challenging or defending patent applications in optical networking should invest heavily at the PTAB stage — by the time a case reaches the Federal Circuit, reversal is the exception, not the rule.
Soto v DERRICK — key questions answered
The Federal Circuit affirmed the USPTO’s determination that patent application US20210143913A1 — covering an optical local area network communication system and method — is unpatentable. The court issued a Rule 36 judgment on 6 February 2025, meaning the affirmance carries no written opinion and creates no binding precedent for third parties.
A Rule 36 judgment allows the Federal Circuit to affirm a lower decision with a single-line order and no written opinion, typically when the panel finds no reversible error and believes an opinion would add no precedential value. For the Soto application (US20210143913A1), it means the USPTO’s unpatentability ruling is final at this appellate level — the application will not proceed to grant in its current form.
Following a Federal Circuit affirmance, the only further appellate avenue is a petition for a writ of certiorari to the United States Supreme Court. Certiorari petitions in patent prosecution matters are rarely granted. The public record of Case No. 23-2008 does not indicate any such petition was filed or is pending.
The ruling is specific to application US20210143913A1 (US17/138794). Any continuation, continuation-in-part, or divisional applications filed by the Soto inventors would be assessed independently on their own claim sets. The prior art record established during prosecution of the parent application may, however, be cited against closely related claims in family members.
The rejection of US20210143913A1 removes it as a potential blocking right for optical LAN technology. However, the Rule 36 nature of the ruling provides no claim-construction guidance. Companies in the optical LAN, passive optical networking, or enterprise fibre sectors should monitor the Soto application family for continuation filings and conduct independent FTO assessments against the broader live patent landscape in this domain.
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