Major step toward a practical Quantum Internet
Breakthrough
- First real-world demonstration of quantum entanglement over a busy commercial fiber network
- Quantum photons traveled 24.4 km through installed telecom fiber
- Shared the cable with high-capacity internet traffic
- Entanglement fidelity exceeded 94%
What is Quantum Entanglement?
- Two particles remain intrinsically linked, even when separated.
- Measuring one instantly determines the state of the other.
- Foundation for:
- Quantum communication
- Quantum teleportation
- Ultra-secure quantum networks
Why This Matters
- Proves quantum signals can coexist with conventional internet traffic
- Eliminates the need for dedicated quantum fiber
- Makes the Quantum Internet more practical and affordable
The Challenge
Classical vs Quantum Signals
- Classical internet: Uses millions of photons
- Quantum communication: Uses single photons
- Even tiny optical noise can destroy quantum information.
Analogy: “Like an ant walking through a herd of elephants.” — Prof. Prem Kumar
How Researchers Solved It
Separate Wavelengths
- Quantum photons: O-band (low-noise region)
- Internet traffic: C-band (standard telecom band)
Optical Filters
- Removed unwanted optical interference.
Ultra-Precise Synchronization
- Used White Rabbit optical timing system.
- Synchronization accuracy:
- Picoseconds (trillionths of a second)
Experiment Setup
Location
- Northwestern University (Evanston) ➜ Downtown Chicago
- Distance:
- 24.4 km
Network Load
- Fiber carried:
- 2 data channels
- 800 Gbps each
- Simulated commercial capacity:
- 36 Tbps
- ≈ 20 million YouTube streams simultaneously
Key Results
- Entangled photons survived the journey.
- >94% entanglement fidelity achieved.
- Performance exceeded what classical communication alone can reproduce.
- Demonstrated compatibility with existing telecom infrastructure.
Earlier Milestone (2024)
Researchers previously:
- Identified a low-noise wavelength for quantum communication.
- Demonstrated 30 km quantum teleportation in the laboratory.
- Current study validates the concept in a real metropolitan network.
Next Goal
Real-World Quantum Teleportation
Researchers aim to:
- Distribute entanglement ✔️ (Now achieved)
- Transfer quantum information (Next challenge)
Potential Applications
- Unbreakable quantum encryption
- Quantum Internet
- Secure cloud computing
- Distributed quantum computing
- Quantum communication networks
- High-security financial & government communications
Study Snapshot
- Published in: Optica Quantum
- Lead Institution: Northwestern University (USA)
- Lead Researcher: Prof. Prem Kumar
💡 Key Takeaway
Researchers successfully transmitted entangled photons through 24.4 km of active metropolitan internet fiber carrying commercial data, proving that quantum communication can operate on existing telecommunications infrastructure—an important milestone toward building a scalable Quantum Internet.
