2012/03/06 by Shuang Wang, Wei Chen, Jun-Fu Guo +5 · 4 citations
Computer Science · Physics and Astronomy · #Advanced Frequency and Time Standards #Atomic and Subatomic Physics Research #Detector #Differential phase #Interferometry #Optical fiber #Photon #Quantum Information and Cryptography #Quantum channel #Quantum cryptography #Quantum information science #Quantum key distribution #Quantum optics #quant-ph
paper · pdf · doi:10.1364/ol.37.001008
published as Optics Letters, 37, 1008-1010 (2012)
openalex publication_date 2012/03/06 · arxiv created 2012/03/20 · arxiv updated 2012/03/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report a demonstration of quantum key distribution (QKD) over a standard telecom fiber exceeding 50 dB in loss and 250 km in length. The differential phase shift QKD protocol was chosen and implemented with a 2 GHz system clock rate. By careful optimization of the 1 bit delayed Faraday-Michelson interferometer and the use of the superconducting single photon detector (SSPD), we achieved a quantum bit error rate below 2% when the fiber length was no more than 205 km, and of 3.45% for a 260 km fiber with 52.9 dB loss. We also improved the quantum efficiency of SSPD to obtain a high key rate for 50 km length.