Homodyne detection for quantum key distribution: an alternative to photon counting in BB84 protocol

摘要

This paper presents the principles and experimental results of an opticalfiber QKD system operating at 1550 nm, and using the BB84 protocol with QPSKsignals. Our experimental setup consists of a time-multiplexed super-homodyneconfiguration using P.I.N detectors in a differential scheme as an alternativeto avalanche photon counting. Transmission over 11km of optical fiber has beendone using this detection scheme and major relevant characteristics such asnoise, quantum efficiency and bit error rate (BER) are reported.