Sterlite Technologies Ltd (STL)
STL completes successful Multi-Core Fiber (MCF) trial with Colt in London, UK
India based STL, a global provider of optical and digital connectivity solutions for AI-era networks, has completed multi-core fiber (MCF) field trials with Colt Technology Services on Colt’s London metro optical network. The trial is a meaningful proof point for space-division multiplexing (SDM) in carrier environments, demonstrating that MCF can lift per-fiber strand capacity while staying within existing civil and duct constraints and improving overall network energy and cost metrics.
The deployment used STL’s Multiverse™ four-core MCF, designed with the same 125 µm cladding diameter as conventional single-mode fibre (SMF) and a 250/200 µm coating, enabling seamless handling with existing cable designs and installation practices. The trial route connected two Colt Points of Presence (PoPs) on the London metro network over spans of approximately 9 km and 63 km, representing both short-haul metro and longer metro-regional use cases.
From a transmission standpoint, the network achieved an 800 Gbps line rate with service validation for 100GE and 400GE, aligning with current high-capacity router and data-centre interconnect interfaces. STL and Colt validated performance across a broad set of optical and system parameters, including chromatic dispersion (CD), polarization mode dispersion (PMD), inter-core crosstalk, throughput, fault behavior, OTDR signatures, insertion loss, and optical return loss (ORL), with results within expected design envelopes. This indicates that Multiverse™ MCF can be engineered and operated to comparable performance baselines as legacy SMF while delivering higher spatial capacity.
Architecturally, STL’s MCF platform integrates four independent cores within a standard SMF cladding profile, effectively multiplying per-fibre capacity without increasing cable diameter. For operators, this directly addresses constraints in congested metro ducts, legacy civil infrastructure, and brownfield routes where augmenting capacity by pulling additional cables is either cost-prohibitive or operationally disruptive. In these scenarios, MCF creates a higher bit-per-mm² and bit-per-duct investment profile, improving both capex efficiency (less civil work, fewer ducts) and opex metrics such as energy per transported bit.
STL positions itself as one of the early movers in taking MCF from controlled lab demonstrations into operational networks, including buried and ducted plant, backed by a full ecosystem spanning fibre, cable, and connectivity hardware through its Optotec portfolio. Coupled with STL’s broader focus on AI-ready optical infrastructure and 5G-ready digital network solutions, the Colt trial underlines a practical migration path for carriers looking to future-proof metro and data-centre interconnect footprints against emerging AI, cloud, and 5G traffic patterns without wholesale rebuilds of underlying passive infrastructure.
“As network demand accelerates, customers are looking for more bandwidth without sacrificing security, performance, or sustainability,” said Buddy Bayer, Chief Operating Officer, Colt Technology Services. “At Colt, we continue to push optical networking forward, and this pilot represents an important step in Europe and the USA. It reflects our focus on building scalable networks that deliver growth in capacity without increasing environmental impact.”
Dr Badri Gomatam, CTO, STL, said the trial highlights the value of joint innovation in advancing optical infrastructure. “Collaborations like this speed up adoption of next-generation connectivity technologies. STL’s Multiverse MCF portfolio is designed for the high-density, ultra-low latency, and resilient connectivity requirements of AI, hyperscale cloud, and future digital platforms globally,” he said. STL stated that the trial results strengthen confidence in MCF as a viable technology for the growing bandwidth requirements driven by AI workloads, cloud scale-out, and new digital services.
“As network demand accelerates, customers are looking for more bandwidth without sacrificing security, performance, or sustainability,” said Buddy Bayer, Chief Operating Officer, Colt Technology Services. “At Colt, we continue to push optical networking forward, and this pilot represents an important step in Europe and the USA. It reflects our focus on building scalable networks that deliver growth in capacity without increasing environmental impact.”
Dr Badri Gomatam, CTO, STL, said the trial highlights the value of joint innovation in advancing optical infrastructure. “Collaborations like this speed up adoption of next-generation connectivity technologies. STL’s Multiverse MCF portfolio is designed for the high-density, ultra-low latency, and resilient connectivity requirements of AI, hyperscale cloud, and future digital platforms globally,” he said. STL stated that the trial results strengthen confidence in MCF as a viable technology for the growing bandwidth requirements driven by AI workloads, cloud scale-out, and new digital services.
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About STL-– Sterlite Technologies Ltd:
STL is a global provider of advanced connectivity solutions, offering end-to-end products and services for building AI-ready networks across FTTx, rural broadband, enterprise, and data centres. With manufacturing operations in North America, Europe, and Asia, STL supplies connectivity solutions in more than 100 countries and works with telecom operators, cloud and data center companies, internet service providers, and large enterprises to build future-ready AI digital infrastructure.
On January 23, 2026, STL reported continued sequential improvement in Operational EBITDA margin for the fifth consecutive quarter, driven by a higher-margin product mix and increased contribution from the US market. With the US–India Bilateral Trade Agreement under advanced discussion, STL remains well-positioned to leverage emerging opportunities by offering reliable, high-quality solutions for building AI-ready digital infrastructure.
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References:
https://www.intechopen.com/chapters/78908
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India ramps up supply chain for 5G service launch in 2021 pending spectrum auction
There is excitement about the anticipated launch of 5G telecom services in India, but the government’s spectrum pricing strategy may be a damper. While the evolving ancillary segments are working on the backbone infrastructure for the 5G roll-out following Reliance Industries Ltd chairman Mukesh Ambani’s assurance that Reliance Jio Infocomm Ltd will launch 5G wireless service in the second half of 2021, experts, however, said that India is not 100% ready.
India telecom equipment company Sterlite Technologies Ltd (STL) said India has been developing 5G infrastructure, but a pan-India roll out will require improving the device, spectrum, wireless and fiber optic ecosystem. “India has the capability of rolling out 5G as we have been building the infrastructure for years now. However, for a countrywide end-to-end deployment, India is not 100% ready… At STL, we will start commercial deployment of open-RAN (open radio access) that is required for 5G by second half of 2021,” said Anand Agarwal, group chief executive at STL. The primary impact of 5G roll-out will be on the commercial ecosystem. According to Agarwal, global supply chains have already matured and are 5G-ready, which makes it easier to import raw material (this author finds that very difficult to believe).
Experts said stressed financials of Bharti Airtel Ltd and Vodafone Idea Ltd (Vi) could discourage them to participate in the 5G launch, in view of the costs involving fiberization and the pricing of spectrum. Airtel and Vi are sitting on massive debts but continue to offer among the lowest tariffs in the world. The telcos have also called for affordable spectrum.
Analysts said the spectrum auction in March may see limited participation from Airtel and Vi due to high reserve prices. Jio, however, is likely to buy spectrum in the 700 megahertz (MHz) band, which is best suited for 5G.
Meanwhile, phone makers have also started producing 5G devices too. Faisal Kawoosa, the founder of techARC, said that India imported nearly two million 5G smartphones in 2020. “While most of these were in ultra-premium range, this year, any new smartphone priced above ₹30,000 should support 5G,” Kawoosa said, adding that 7-9% of all smartphones sold in India in 2021 are likely to support 5G, making it nearly four times the imports. However, will those so called “5G” users actually get 5G service, especially when roaming?
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The big 3 Indian telcos are likely to voice their concerns to the Department of Telecommunications (DoT) as the National Frequency Allocation Plan (NFAP-2018) has not been updated by the department’s wireless planning cell (WPC) more than a year after several new airwave bands, including the 26 Ghz spectrum, were identified by the ITU-R WRC 19 for 5G deployments worldwide, including in India.
The NFAP is a central policy roadmap that defines future spectrum usage by all bodies in the country, including DoT, the Department of Space and the defence ministry. Telcos want it revised quickly as any further delay could potentially hinder the auctioning of the premium millimetre-wave 5G bands.
“The NFAP-2018 needs to be revised expeditiously by the WPC to align different stakeholders if a meaningful 5G auction is to happen later this year, and the industry will take up the matter with DoT,” a senior industry executive told ET.
In November 2019, WRC-19 identified a set of new airwaves, including the 24.25-27.5 Ghz (popularly known as the 26 Ghz band), 37-43.5 Ghz, 45.5-47 Ghz, 47.2-48.2 Ghz and 66-71 Ghz bands for 5G services. However, none of these bands (primarily the mm waves) have been included in India’s NFAP. Note also that ITU-R WP5D has not yet agreed on a revision of ITU-R M.1036 which would include the new frequency arrangements agreed during WRC 19 for terrestrial IMT deployments.
