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Generation and Coherent Control of Pulsed Quantum Frequency Combs
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Integrated InP-based transmitter for continuous-variable quantum key distribution
Optics Express
|August 13, 2025
Summary
This study developed a compact quantum key distribution (QKD) transmitter using indium phosphide (InP) photonic integrated circuits (PICs). The system achieved a 78 kbps secret key rate over 11 km fiber, demonstrating potential for market adoption.
Area of Science:
- Quantum Information Science
- Integrated Photonics
- Quantum Cryptography
Background:
- Quantum Key Distribution (QKD) systems offer enhanced security but face challenges in size, cost, and complexity.
- Monolithic Photonic Integrated Circuits (PICs) present a solution for miniaturizing and cost-effectively producing QKD systems.
Purpose of the Study:
- To design, fabricate, and characterize an InP-based PIC transmitter for Continuous-Variable (CV) QKD.
- To evaluate the performance of the integrated CV-QKD system in a practical fiber optic channel.
Main Methods:
- Development of an Indium Phosphide (InP) based PIC transmitter.
- Implementation of a pulsed Gaussian-modulated coherent state (GMCS) CV-QKD protocol.
- Experimental testing over an 11 km optical fiber channel.
Main Results:
- Successful design, fabrication, and characterization of the InP PIC transmitter.
- Demonstrated a secret key rate of 78 kbps in the asymptotic regime over 11 km fiber.
- The system's performance is compatible with practical CV-QKD applications.
Conclusions:
- InP-based PICs hold significant potential for integrating CV-QKD systems onto a single, compact platform.
- This technology can accelerate the adoption of QKD in various markets due to reduced size, cost, and complexity.
- The demonstrated performance validates the feasibility of integrated PICs for secure quantum communication.
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