Efficient quantum cryptography with coherent-state light in optical fibers at Gbps rates

摘要

We demonstrate high-speed (0.25Gbps) data encryption over 50km of telecom fiber using coherent states of light. For the parameter values used in the experiment, the demonstration is secure against individual ciphertext-only eavesdropping attacks near the transmitter with ideal detection equipment. While other quantum cryptographic schemes require the use of fragile quantum states and ultra-sensitive detection equipment, our protocol is loss tolerant, uses off-the-shelf components, and is optically amplifiable.