Review of India's Progress and Prospects in Quantum Satellite Communication

 Review of India's Progress and Prospects in Quantum Satellite Communication

 

India is poised to achieve quantum satellite communication by 2030, a goal deemed "a must for India" by officials. This ambitious undertaking, spearheaded by the National Quantum Mission (NQM), aims to establish highly secure communication networks using quantum key distribution (QKD) via satellites. While significant progress has been made in ground-based demonstrations, particularly with optical fiber networks, bridging the gap to free-space satellite communication necessitates substantial investment, a large multidisciplinary expert team, and the active involvement of quantum startups. Challenges include mitigating atmospheric disturbances in free-space channels and catching up to countries like China, which has a decade-long head start in this technology.

 

1. The "Why" of Quantum Satellite Communication for India:

 

Enhanced Security: The primary driver for India's pursuit of quantum communication is the need for "safe quantum communication." This is achieved through the use of "quantum keys" made of photon streams.

Quantum Key Distribution (QKD): QKD leverages the principles of quantum mechanics to ensure secure information transmission. One particularly secure, though technically challenging, approach uses "quantum entanglement," where a change in one entangled photon instantaneously reflects in another, making any hacking attempt immediately apparent.

Overcoming Distance Limitations of Cables: While secure keys can be generated via physical networks like fiber optic cables, "the goal is to be able to do it in ‘free-space’ or without such intervening wires." This is because "the cost of such transmissions using cables rapidly rises once the sender and receiver are hundreds of kilometres apart." Satellites offer an ideal solution as they "can act as an intermediary between any two points even if they are thousands of kilometres apart."

2. India's Ambition and Timeline:

 

2030 Target: Professor Bhaskar Kanseri of IIT-Delhi states that India could be technologically capable of "quantum communication" using satellites in the "next half a decade," implying a target of 2030.

National Quantum Mission (NQM): The NQM is providing "a strong focus to develop satellite-based long distance quantum communication," indicating a national strategic priority.

Catching Up with Global Leaders: While "China had demonstrated satellite-based quantum communication nearly one decade ago," having started their quantum communication activities in the early 2000s, Prof. Kanseri "strongly believe[s] that India, which started quite recently (in the 2020s), will achieve it in next half-a-decade or so."

3. Current State of Play and Demonstrated Capabilities in India:

 

Ground-Based Progress (Fiber Optic): Prof. Kanseri's team demonstrated an "intercity quantum-communication link between Vindhyachal and Prayagraj in 2022, using commercial-grade underground dark optical fibre."

In 2024, the team "successfully distributed quantum keys using entanglement over a 100 km spool of telecom-grade optical fibre" in a project supported by the Defence Research and Development Organisation (DRDO).

Ground-Based Progress (Free-Space): In January 2022, scientists from the Department of Space (DOS) "jointly demonstrated quantum entanglement-based real-time Quantum Key Distribution (QKD) over a 300-metre atmospheric channel."

In 2021, a team led by Urbasi Sinha "demonstrated perhaps the first instances of such free-space communication in Bangalore over a building separated by 50 metres."

Prof. Kanseri's team recently reported "an instance of quantum key distribution one kilometre apart — the farthest such transmission in India, without any connecting cables."

Proof of Concept (POC): IIT-Delhi's experiments so far are primarily "proof of concept (POC) nature" conducted with small teams.

4. Challenges and Requirements for Satellite-Based Quantum Communication:

 

Funding and Manpower: Achieving quantum satellite communication "would require not only adequate funds but also a large, dedicated team of multidisciplinary skilled experts for developing several types of enabling technologies."

Atmospheric Disturbances: "Using fibre optic cables provides a stable channel for quantum communication which free-space channels do not." Atmospheric factors such as "turbulence, air flow, pollution, etc., particularly in a city such as the Delhi National Capital Region, made it more 'challenging' to demonstrate free-space quantum communication." These disturbances cause the "photon beam of quantum channel diverges and wanders... and results in more errors."

Indigenous Development: "Indigenous development of needed equipment and components is also required."

Role of Startups: "Quantum startups, mentored by researchers working in quantum technologies, if funded adequately, can contribute immensely in translation of technologies from lab to market, and in prototyping quantum technologies in a focussed and faster manner."

Global Benchmarks: India still "has much to cover regarding QKD-entanglement communication" compared to ground demonstrations in Europe, Canada, and the United States of free-space QKD greater than 100 km, and China's satellite-based achievements (500 km satellite, ground stations 1,000 and 1,700-km apart).

Conclusion:

 

India's ambition to achieve quantum satellite communication by 2030 is well-defined and supported by national initiatives. While foundational work in quantum key distribution has been demonstrated both in fiber optic and limited free-space environments, significant investment in funding, talent, and infrastructure, coupled with strategic collaboration with startups, will be crucial to overcome the technical challenges and bridge the existing gap with leading nations in this cutting-edge field.