In a significant leap for India’s quantum communication ambitions, the Centre for Development of Telematics (C-DOT) and Sterlite Technologies Ltd. (STL) have successfully demonstrated India’s first Quantum Key Distribution (QKD) transmission over a 4-core Multi-Core Fibre (MCF). This milestone showcases a major step forward in building secure, next-generation telecom networks powered by indigenous innovation.
The successful trial, which established a stable QKD link over 100 km, allows the integration of quantum-secure signals and classical high-speed data on a single optical fibre. This marks a breakthrough in cost-effective quantum deployments, laying the groundwork for India’s secure digital future.
Revolutionising Secure Communication with Multi-Core Fibre
Traditionally, QKD systems require a dedicated dark fibre channel to preserve the integrity of the signals. The deployment of STL’s Multi-Core Fibre overcomes this limitation by enabling space division multiplexing—transmitting quantum signals on one core while the remaining cores simultaneously handle classical data traffic. This ensures physical isolation and signal integrity, dramatically reducing fibre infrastructure costs and improving scalability.
The test demonstrated that quantum and classical signals can co-exist within the same cable, validating MCF’s potential for integrated quantum-classical networks. This is a game-changing advancement for real-world implementation of secured communication systems.
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Strengthening India’s Quantum and Optical Ecosystem
C-DOT, the R&D arm of the Department of Telecommunications (DoT), has been spearheading India’s efforts in communications. Its QKD systems have already received Technology Approval from the Telecommunication Engineering Centre (TEC). Meanwhile, STL’s innovation in developing 4-core and 7-core MCF is transforming the optical landscape for scalable and secure fibre networks.
The collaboration underscores India’s growing competence in homegrown infrastructure and reinforces the critical role of public-private partnerships in accelerating deep-tech adoption. As cyber threats grow and digital sovereignty becomes a priority, this development puts India firmly on the global QKD innovation map.
