In a groundbreaking development for quantum communication, researchers at the Indian Institute of Technology (IIT) Delhi, in collaboration with India’s Defence Research and Development Organisation (DRDO), have achieved wireless quantum communication over a distance of more than one kilometer in open-air conditions.

This is the longest such demonstration in India and a clear signal that quantum networks without fiber-optic infrastructure are becoming a real-world possibility—with enormous implications for secure military communication, national defense, banking, and satellite-based quantum internet.

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Breaking Free from Fiber: Why It’s a Big Deal

Until recently, most quantum communication efforts have relied on fiber-optic cables to transmit quantum keys or entangled particles. While effective over short distances, fiber networks face severe limitations when it comes to long-range or mobile quantum applications.

IIT Delhi’s breakthrough shows that secure, line-of-sight quantum communication is viable even without cables—using entangled photons beamed through the air across a 1+ km stretch.

The experiment achieved a Quantum Bit Error Rate (QBER) of just 7%, well below the industry benchmark of 11% for secure key generation.

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How It Works: Quantum Key Distribution in Open Air

This experiment used free-space Quantum Key Distribution (QKD), a technology that allows two parties to share a secure cryptographic key by transmitting entangled photons. If a hacker tries to intercept or measure these photons, the quantum state collapses—instantly alerting the sender and receiver.

IIT Delhi’s setup involved:

• Polarization-entangled photon sources

• High-precision tracking and alignment systems

• Real-time synchronization and error correction protocols

Together, this allowed them to send quantum-encrypted signals wirelessly—a key step toward mobile, ground-to-satellite, or drone-based quantum networks.

India’s Quantum Ambitions Take Flight

This achievement is part of a broader push by the Indian government to become a global leader in quantum technology. India’s National Quantum Mission, with a budget exceeding ₹6,000 crore (~$725 million), aims to:

• Build quantum communication networks across strategic sectors

• Develop indigenous quantum hardware

• Train a skilled quantum workforce

IIT Delhi’s wireless QKD system could eventually serve:

• Military bases and forward deployments

• Satellite-to-ground quantum links

• Financial networks requiring next-gen security

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The Road Ahead: Toward a Quantum Internet

The demonstration echoes similar efforts in China, the U.S., and the EU to develop quantum-secured infrastructure. While challenges remain—such as scaling, weather resistance, and system alignment—this success:

• Eliminates the need for physical cabling

• Opens doors for satellite-based QKD

• Reduces vulnerability in mobile or temporary communication setups

Future steps include:

• Increasing range beyond 10 km

• Integrating quantum repeaters for longer distances

• Testing in dynamic environments (e.g., from drones or vehicles)

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Conclusion: A Wireless Leap Toward Quantum Security

With this demonstration, IIT Delhi has placed India firmly on the global quantum map. The ability to transmit entangled quantum states wirelessly over open air represents a significant step toward the future of hack-proof communication networks—not just for governments, but eventually for businesses and consumers.

In a world increasingly dependent on digital infrastructure, quantum-secure wireless networks may soon become as essential as encryption is today—and IIT Delhi has shown us the first glimpse of that future.