Novel Single-Photon Differential Phase-Shift Keying With Asymmetric High-Bit-Rate Coding and Low-Bit-Rate Gated Receiving Coding Data Format

• DOI: 10.1109/jlt.2024.3401147
• Publication Date: 2024-05-15T17:38:44Z
• Authors: Kuan-Wei Hu; Chih-Hsien Cheng; Atsushi Matsumoto; Kouichi Akahane; Jau-Yang Wu; Yuh-Renn Wu; Gong-Ru Lin
• Keywords: Differential phase; Bit (key)

A novel single-photon differential phase-shift keying (DPSK) scheme with asymmetric high-bit-rate coding (at 192 Mbit/s) and low-bit-rate gating (1 data format is proposed to stabilize the long-term long-distant point-to-point secure communication over 40-km standard single-mode-fiber (SSMF). The carrier served by an attenuated distributed-feedback laser diode ultralow phase power fluctuations of Δθ/θ<0.005% ΔP/P<0.01%. successively encoded pulsed return-to-zero (RZ) clock DPSK bits at 192-Mbit/s decoded a synchronized one-bit-delay interferometer enhanced immunity spectral thermal noise. detected within 1-ns transistor-transistor logic (TTL) gated window 0.1% duty-cycle 1-Mbit/s receiver. Such encoding receiving further codes quantum bit error ratio (QBER) 0.038% when interfered free range 4.8 MHz expands broader than linewidth 293 kHz ensure interferometric visibility 99.2% operating time beyond 1065 s. Decoding average photon number 0.2 #/bit guarantees BER 1.5% key rate 113.4 kbit/s under back-to-back transmission, remains 3.2% 10.1 40-km-SSMF transmission. low-bit-rate-gated transmitted has unveiled stabilization for communications.