Researchers at the DRDO-Industry-Academia Centre of Excellence (DIA-CoE) at IIT Delhi, in collaboration with the Defence Research and Development Organisation (DRDO), have successfully demonstrated quantum entanglement-based communication over a distance exceeding one kilometer. This experiment, conducted using a free-space optical link across the IIT Delhi campus, marks a significant leap towards the realization of ultra-secure quantum communication networks in India.
Quantum entanglement, a phenomenon Albert Einstein famously called “spooky action at a distance,” is at the heart of the next revolution in secure communications. When two particles are entangled, the state of one instantly influences the other, no matter how far apart they are. This property can be harnessed to create communication channels that are fundamentally immune to eavesdropping; a promise that has driven global research into quantum networks.
The DIA-CoE team at IIT Delhi established a free-space optical link, transmitting entangled photons across more than one kilometer of open air. This demonstration is the first of its kind in India at such a distance, proving that quantum-secure communication is feasible outside controlled laboratory conditions. The setup involved state-of-the-art photon sources, precision alignment systems, and ultra-sensitive detectors, all meticulously calibrated to maintain entanglement integrity over the challenging free-space environment.
This experiment is a crucial step towards the development of Quantum Key Distribution (QKD) systems, which use quantum mechanics to enable two parties to generate a shared, secret cryptographic key—guaranteeing security even against the most sophisticated hacking attempts.
The ability to transmit quantum information securely over long distances is a cornerstone of the future “quantum internet.” Unlike traditional encryption, which can be broken with enough computational power, quantum communication is protected by the laws of physics. Any attempt to intercept or measure the quantum signal immediately disturbs it, alerting the communicating parties and rendering the attack futile.
For India, this breakthrough has profound implications for defense, finance, and critical infrastructure, where data security is paramount. The collaboration between DRDO and IIT Delhi demonstrates the power of academia-industry-government partnerships in pushing the boundaries of innovation.
This achievement aligns with India’s National Mission on Quantum Technologies and Applications (NMQTA), which aims to position the country as a global leader in quantum research and its real-world applications. With this successful demonstration, India joins an elite group of nations—including China, the US, and several EU countries—actively developing quantum-secure communication technologies.
The IIT Delhi-DRDO team’s work will accelerate the deployment of quantum networks across strategic sectors, enabling secure military communications, financial transactions, and even quantum-safe internet for citizens in the future.
