Sterlite Technologies Ltd (STL) won a final, non-appealable victory as the European Patent Office's Technical Board of Appeal fully revoked Fujikura’s patent EP3796060. The decision completely dismisses an ongoing UK patent infringement lawsuit targeting STL's Celesta cable products. STL faces no penalties and is seeking legal cost recovery.
LONDON — Global optical and digital solutions provider Sterlite Technologies Ltd (STL) has secured a decisive legal victory in Europe, successfully overturning a patent infringement challenge brought against it by Japanese telecommunications giant Fujikura Ltd. The Technical Board of Appeal of the European Patent Office (EPO) in Munich, Germany, has issued a final, non-appealable ruling revoking Fujikura's European Patent EP3796060 in its entirety. The landmark decision effectively dissolves the ongoing patent infringement litigation in the United Kingdom regarding STL’s signature Celesta cable family, resolving a multi-year legal overhang for the Indian multinational provider.
Technical Board of Appeal Delivers Final Judgment
The dispute originated on November 10, 2023, when Fujikura Ltd and its subsidiary Fujikura Europe Ltd filed patent infringement proceedings against Sterlite Technologies in the High Court of Justice of England and Wales. Fujikura alleged that STL's high-density, reduced-diameter ribbed optical fiber cables supplied to the United Kingdom infringed upon European Patent EP 3 796 060 B1, which covered specific design mechanics meant to assist air-blown installation inside telecom ducts. The Japanese company had sought a permanent injunction to block all further sales and supply of these optical fiber cable lines in the UK market.
Following an initial split judgment in the UK High Court during late 2025—which had held that STL’s ultra-high-fiber-count cables did not infringe while its lower-fiber-count variants did—STL aggressively pursued an appeal directly at the central European regulatory level. By completely revoking Fujikura's underlying patent, the EPO Technical Board of Appeal has neutralized the legal foundation of the entire UK infringement claim.
In a comprehensive regulatory disclosure submitted under Regulation 30 of the Securities and Exchange Board of India (SEBI) Listing Obligations and Disclosure Requirements, Sterlite Technologies confirmed:
"Fujikura's patent EP3796060, involved in patent infringement litigation in the UK... has been revoked in its entirety by the Technical Board of Appeal. This effectively brings a formal end to the UK patent litigation concerning the company's Celesta cable family."
Because the European Patent Office's appellate tribunal holds absolute authority over European patent validity, this ruling is legally final and cannot be appealed further by Fujikura, erasing any outstanding financial claims, settlements, or legal penalties against STL.
Structural Clearances and Market Impact
The complete dismissal of the litigation has immediate positive ramifications for international telecommunications operators, enterprise data center developers, and digital infrastructure investors. The Celesta cable family represents a core pillar of STL’s global product portfolio, custom-engineered to meet high-density broadband demands triggered by artificial intelligence workloads and aggressive 5G telecom expansions.
With the legal barriers removed, STL is poised to expand its market share across the UK and continental Europe without the threat of supply disruptions. Furthermore, the company announced that it has formally initiated legal mechanisms to recover its extensive defense costs directly from Fujikura.
Official Sources Section
The information detailed in this report is sourced directly from official corporate and regulatory filings, including:
The formal regulatory compliance submission by Sterlite Technologies Limited to the National Stock Exchange of India (NSE) and the BSE Limited under SEBI guidelines.
Official case records from the Technical Board of Appeal of the European Patent Office (EPO) located in Germany.
Historical civil high court records from the High Court of Justice Business and Property Courts of England and Wales.
Executive and Legal Perspectives
According to official exchange filings released by corporate representatives, the ruling marks an unmitigated defense of the company’s independent research and development.
"STL remains fully committed to protecting and developing its technologies and to delivering cutting-edge solutions to customers globally," the company stated in its presentation to market regulators. Legal representatives confirmed that because there is no compromise or out-of-court settlement involved, the resolution establishes a clean legal precedent for the supply of their ribbed optical fiber cable technologies throughout European territories.
Why It Matters
For global network operators, this development guarantees supply chain stability. Had Fujikura succeeded in obtaining an injunction, telecom carriers deploying ultra-dense fiber webs in major metropolitan areas could have faced severe supply shortages or project delays. For public investors in STL (STTE.NS), the removal of this intellectual property overhang eliminates potential liabilities, stabilizing the company's long-term valuation as it scales up international production.
Key Facts at a Glance
The Ruling Agency: The Technical Board of Appeal of the European Patent Office (Germany) completely revoked Fujikura's patent EP3796060.
Legal Status: The decision is final, non-appealable, and immediately terminates all derivative UK infringement lawsuits.
Affected Product Line: STL's proprietary Celesta ultra-high-density optical fiber cable family is cleared of all infringement claims.
Financial Outcome: Zero penalties or settlement fees are owed by STL; the company is actively pursuing the recovery of its legal defense costs from Fujikura.
FAQ Section
What was the core issue in the patent dispute between Sterlite Technologies and Fujikura?
Fujikura alleged that Sterlite Technologies’ ribbed optical fiber cables infringed on its patented design intended to improve air-blown installations inside underground conduits. STL maintained that its technology was independently developed and counter-sued to revoke the patent's validity.
What does the absolute revocation of a patent by the EPO mean?
When the European Patent Office's Technical Board of Appeal revokes a patent "in its entirety," the patent is treated as though it never legally existed across all participating European nations. Consequently, any active infringement lawsuit based on that patent automatically loses its legal foundation and must terminate.
Will this ruling impact the availability of STL Celesta cables in the market?
Yes, positively. The decision removes all legal uncertainty regarding the supply, sale, and deployment of the Celesta cable family throughout the United Kingdom and continental Europe. Telecommunication firms can continue integration plans without risk of court-ordered injunctions.
Sources: Sterlite Technologies Limited Regulatory Filings, European Patent Office Registry, National Stock Exchange of India Corporate Disclosures.
