Digital feedforward carrier phase estimation for PSK Y-00 quantum-noise randomized stream cipher

Abstract

Encryption in fiber-optic transmission is one of remaining issues in modern communication systems. One of the solutions is to use Y-00 quantum-noise randomized stream cipher. In this paper, we propose feedforward carrier phase estimation (CPE) with Y-00 decryption process for digital-coherent detection of phase-shift keying (PSK) Y-00 signal. After decryption of Y-00 signal in a digital domain, carrier phase is estimated by calculating Mth power of signal complex amplitude. Numerical simulations for 10-Gbaud PSK Y-00 signal show that the feedforward CPE with decryption process, which is used by a legitimate receiver who shares keys, successfully tracks phase noise. Consequently, penalty-less demodulation of Y-00 signal is achieved.