The European Patent Office Technical Board of Appeal has completely revoked Fujikura’s patent EP3796060. This non-appealable ruling formally terminates parallel patent infringement litigation in the UK concerning Sterlite Technologies’ Celesta cable family, allowing the company to securely advance its high-density fiber networks across Europe.
LONDON, United Kingdom — Indian digital infrastructure and optical fiber pioneer Sterlite Technologies Limited (NSE: STLTECH) achieved a major regulatory and legal victory on Friday, July 3, 2026, as its multi-year cross-border patent dispute with Japanese electrical equipment giant Fujikura Limited came to a definitive close. The Technical Board of Appeal of the European Patent Office (EPO) issued a final, non-appealable decision completely revoking Fujikura’s European Patent EP3796060 in its entirety. The total cancellation of the underlying intellectual property (IP) automatically and permanently invalidates the parallel patent infringement lawsuit pursued by Fujikura in the High Court of Justice of England and Wales concerning Sterlite’s flagship Celesta micro-cable product family.
EPO Board Erases Competitor’s High-Density Ribbon Claims
The definitive ruling by the Munich-headquartered European Patent Office represents a major strategic turnaround in the high-stakes global fiber infrastructure sector. The contested patent, originally granted to Tokyo-based Fujikura, covered specialized design parameters for reduced-diameter, high-density optical fiber cables developed for air-assisted blown installation into narrow city ducts and underground conduits.
Fujikura had leveraged this patent to claim that Sterlite Technologies’ proprietary multi-tube micro-cables unauthorizedly duplicated its structural layout, leading to an aggressive enforcement campaign across European jurisdictions. However, following intense technical evaluations, the EPO Technical Board of Appeal determined that Fujikura's engineering claims lacked the necessary innovative novelty and inventive step baseline relative to pre-existing prior art. By executing a complete revocation of the patent text, the appellate authority effectively declared that the design boundaries were part of public standard knowledge, granting Sterlite complete freedom of operation across all European Union and UK digital network markets.
Formal Termination of Costly UK High Court Injunction Battle
The erasures of the European patent text dismantle the legal foundations of the prolonged litigation unfolding within the United Kingdom. Fujikura, alongside its regional subsidiary Fujikura Europe Limited, originally initiated patent infringement proceedings against the Indian multinational in the UK High Court on October 23, 2023. The lawsuit sought permanent injunctions to block the marketing, sale, and physical installation of Sterlite’s high-density Celesta cables across British telecom networks.
While early-stage UK court rulings in late 2025 had briefly favored the Japanese firm's structural interpretations, the absolute supremacy of the EPO's invalidation order overrides any localized regional findings. Following the formal wrap of the patent text, Sterlite Technologies confirmed it has instructed its international legal teams at Allen & Overy Shearman Sterling LLP to immediately file for the full recovery of its extensive multi-year legal defense and trial expenditures directly from Fujikura.
Impact on Global Broadband Projects and Equity Investors
For international telecommunications carriers, cloud hyperscalers, and sovereign broadband developers, the total clearance of the Celesta cable line restores vital supply chain diversity. The Celesta product series utilizes advanced intelligently bonded ribbon fibers, packing hundreds of individual data-carrying fiber strands into ultra-compact, lightweight structural sleeves that are pushed through ducts via compressed air.
If Fujikura had successfully preserved its patent monopoly, telecom network builders across Western Europe would have faced a highly restricted market, driving up the layout costs for next-generation 5G and fiber-to-the-home (FTTH) rollouts. For capital market investors, the removal of the European legal overhang secures the long-term export projections of Sterlite’s manufacturing facilities in Silvassa and Europe, allowing the enterprise to freely capture expanding smart-city infrastructure tenders without running into compliance bottlenecks or liability provisions.
Official Sources Section
The international patent decisions, legal case index entries, structural product criteria, and cost recovery files detailed in this global technology report are verified through:
The statutory corporate disclosure files submitted under listing guidelines to the National Stock Exchange of India Limited (NSE)
The centralized case disposition database maintained by the European Patent Office (EPO)
The official litigation docket sheets recorded by the High Court of Justice, Patents Court of England and Wales.
The global industrial IP updates published by property analytics portal ScanX.
Quote Section
"The Technical Board of Appeal of the European Patent Office has revoked Fujikura's patent EP3796060 in its entirety. This non-appealable decision formally ends the UK patent litigation concerning Sterlite's Celesta cable family. Following this definitive outcome, the company is actively pursuing the total recovery of its legal defence costs from Fujikura."
— Official Corporate Invalidation Filing, Legal & Compliance Division, Sterlite Technologies Limited
"According to officials close to the international telecommunications distribution networks, the full legal vindication of the multi-tube design layout removes an expensive structural risk barrier, stabilizing purchasing choices for tier-one telecom operators throughout the European region."
Why It Matters
The absolute revocation of the competitor's patent layout introduces key practical implications across the tech sector:
For Broadband Operators: Telecom providers can continue deploying Sterlite's Celesta micro-cables without fearing future litigation, securing access to competitive infrastructure pricing.
For Corporate Shareowners: Resolving the European litigation eliminates long-term compliance liabilities, strengthening the firm's small-cap valuation and asset safety across global bourses.
For Intellectual Property Law: The outcome demonstrates how centralized European patent challenges can efficiently resolve costly, fragmented patent battles in individual national courts.
Key Facts at a Glance
Absolute Invalidation: The European Patent Office completely revoked Fujikura's EP3796060 design patent.
UK Litigation Ended: The non-appealable EPO board ruling automatically terminates the parallel infringement case in the UK High Court.
Celesta Cleared: Sterlite's high-density Celesta cable family is cleared of all lingering IP infringement claims in European markets.
Cost Recovery Launched: Sterlite has commenced formal legal actions to recover its multi-year defense and court costs from Fujikura.
FAQ Section
What specific optical fiber technology was at the center of the dispute between Sterlite and Fujikura?
The litigation centered on specialized engineering methods for manufacturing high-density, reduced-diameter optical fiber micro-cables designed for air-blown installation inside tight underground city conduits.
Can Fujikura appeal the European Patent Office's decision to revoke its patent?
No. The formal determination issued by the Technical Board of Appeal of the European Patent Office represents a final, non-appealable administrative decision, permanently stripping the patent of all legal enforceability across member countries.
How will this ruling affect telecom operators currently using Sterlite’s Celesta cables?
The ruling completely removes the risk of any court-ordered sales bans or usage injunctions across the United Kingdom and Europe, ensuring that current and future infrastructure rollouts can continue smoothly.
Source: National Stock Exchange of India Listing Records, European Patent Office Appeal Registers, ScanX Market Dispatches, UK Patents Court Archives.
