DRDO Sends Secrets at the Speed of Light – No Wires Attached! Quantum Internet.

Yes, you can absolutely use light to transfer data — and in fact, it's already widely used in modern communication systems. Here are a few key examples and technologies where light is used to transmit data:

✅ 1. Optical Fiber Communication

• How it works: Data is transmitted as pulses of light through thin strands of glass or plastic (optical fibers).

• Speed: Extremely high bandwidth and speed (up to terabits per second).

• Use cases: Internet backbones, undersea cables, data centers.

• Light source: Laser or LED.

✅ 2. Li-Fi (Light Fidelity)

• How it works: Uses LED light bulbs to transmit data by modulating the light intensity (too fast for the human eye to see).

• Advantage: Very high speed, secure (light doesn’t penetrate walls).

• Use case: Indoor wireless communication, smart buildings, aircraft, hospitals (no radio interference).

• Alternative to: Wi-Fi (which uses radio waves).

✅ 3. Infrared Communication

• How it works: Uses infrared light (just beyond visible light spectrum) to transmit data.

• Used in: TV remotes, short-range data transfer between devices (e.g., early phones, IR blasters).

• Limitations: Line-of-sight needed, limited bandwidth.

✅ 4. Free Space Optical Communication (FSO)

• How it works: Data is transmitted through the air using laser light between two points.

• Use case: Satellite communication, building-to-building links.

• Challenge: Affected by fog, rain, and obstacles.

✅ 5. Visible Light Communication (VLC)

• A broader category that includes Li-Fi.

• Can be used for indoor navigation, vehicle-to-vehicle communication, and smart lighting.

🔬 Real-Life Example:

If you’ve ever used fiber-optic internet, you’re already using light to transfer data — it just happens in cables rather than through open air.

DRDO and quantum internet

DRDO (Defense Research and Development Organization) in India has indeed experimented with quantum communication, sometimes informally referred to as steps toward a "quantum internet."

Here’s a quick breakdown:

🇮🇳 DRDO’s Work on Quantum Communication

• In 2021, DRDO successfully demonstrated Quantum Key Distribution (QKD) over a distance of 100+ km between Prayagraj and Vindhyachal in Uttar Pradesh.

• This was a major milestone in developing a secure quantum communication network for defense applications.

• The project was in collaboration with Tata Institute of Fundamental Research (TIFR) and other research institutions.

💡 What Is Quantum Communication?

Quantum communication uses the principles of quantum mechanics, especially entanglement and superposition, to transmit data in a way that's impossible to hack without detection.

🔐 Quantum Key Distribution (QKD)

• Used to securely share encryption keys.

• If an eavesdropper tries to intercept the communication, the quantum state collapses, and the intrusion is immediately detected.

• Light (usually photons) is used as the carrier of quantum information.

🌐 Quantum Internet (Future Vision)

While we’re not fully there yet, the quantum internet aims to:

• Connect quantum computers.

• Share quantum entanglement between distant locations.

• Enable ultra-secure communication networks.

💡 So, to tie it back:

Yes — light is the medium, and quantum technologies like QKD use photons (light particles) to securely transmit information. DRDO is using this cutting-edge light-based method to build secure communication systems.

Real-world analogy for how QKD or quantum internet works?

🎓 Analogy: The Magic Lock and the Spy

🧑‍🏫 Imagine this:

You (Alice) want to send a secret message to your friend Bob. But you’re worried someone (let’s call him Eve, the eavesdropper) might spy on it.

Now, instead of using a regular lock, you both use a "magic lock" that behaves in a very strange way — like quantum particles.

🧲 The Quantum Lock (Photon)

• You send tiny particles of light (photons) to Bob.

• Each photon has a random orientation, like being tilted → / or ↗ or ↑ or ↘.

• These tilts represent bits (0s and 1s), like binary information.

But here's the magic:

👻 If anyone tries to look at the photon on the way, it changes its tilt! That’s quantum mechanics: you can’t observe without disturbing.

So, if Eve tries to spy, you and Bob will notice something weird:

The tilts will no longer match when Bob checks them.

🔐 Quantum Key Distribution (QKD)

• You and Bob compare notes on which tilts you used after the photons arrive.

• Any mismatch means someone spied.

• You discard the bad data and use only the correct matching photon directions to create a secret key — like a password.

Now, you use that key to encrypt your actual message (which can be sent by normal means).

🤖 What About the Quantum Internet?

Imagine a future where:

• Every city, military base, or hospital has a quantum router.

• It sends entangled photons instead of regular signals.

• Anyone using it can share keys or data that can’t be intercepted, ever.

• Even quantum computers in different cities could work together instantly using quantum entanglement.

🧠 Summary (Simple Points):

🌐 Quantum Internet — What's Coming?

🔹 A spy-proof network for government, defense, and future businesses 🔹 Entangled particles used for instant coordination between systems 🔹 Quantum-secure communication between cities, satellites, or even banks

India is among the few countries investing heavily in this — not just for military, but possibly for commercial quantum networks in the future.

🔦 Light is Not Just Fast — It’s the Future

From:

• 💡 Fiber Optics

• 🔦 Li-Fi

• 🌫️ Free Space Optical Communication (FSO)

• 🧿 Quantum Communication

...we're seeing light evolve from a medium of illumination to the backbone of future data transmission.

The next time you switch on a light, just remember: You’re looking at the same medium that might one day power the Quantum Internet.

Did DRDO use physical wires for message transmission?

✅ No, DRDO did not use traditional wire (like copper or fiber) to send the actual quantum-secure message.

Instead, DRDO used Free-Space Optical Communication (FSO) — meaning:

🟢 Data was transmitted using light (photons) through open air, not through physical wires.

🔬 Here’s What DRDO Actually Did:

• DRDO successfully demonstrated Quantum Key Distribution (QKD) over a distance of 100+ km.

• The setup involved free-space transmission of photons between two locations: Prayagraj and Vindhyachal.

• It used quantum optics — with lasers and entangled photons — to securely transmit keys.

📡 What Is Free-Space Quantum Communication?

It's like pointing a laser from one hilltop to another — only the laser carries quantum information. No cables, no radio waves — just photons flying through the air.

This is different from:

• 🔌 Wired communication (e.g., fiber optics)

• 📶 Wireless RF (like Wi-Fi or 5G)

⚠️ Challenge They Solved:

• Free-space quantum communication is tricky because atmospheric disturbances (dust, fog, turbulence) can distort or lose photons.

• DRDO’s success shows it’s possible to have secure, real-time communication without wires, even over long distances.

📌 In Summary: