India, Oct. 3 -- India has successfully demonstrated its first 5.56-km free-space Quantum Key Distribution (QKD) link, marking a field milestone in the development of quantum-secure communication infrastructure. The demonstration was carried out by QNu Labs in collaboration with Bhaskaracharya National Institute for Space Applications and Geo-informatics (BISAG-N) and IIT Gandhinagar, establishing a secure quantum communication channel between BISAG-N and the institute.

The field trial used QNu Labs' Pointing, Acquisition and Tracking (PAT) system and achieved a stable Quantum Bit Error Rate (QBER) of below 5%. The system generated secure cryptographic keys at a rate of 230-260 bits per second (bps). These keys were subsequently integra...