500 Mbps high-speed high-sensitivity photon-counting communication demonstration system

We propose and demonstrate a high-speed, high-sensitivity photon communication system based on a 16-pixel superconducting nanowire single-photon detector (SNSPD) array. This system integrates high-speed transmission of narrow optical pulses and multi-channel array high-speed signal detection and reception. By incorporating the proposed channel log-likelihood ratio correction and high-speed slot synchronization algorithm, the system's performance is enhanced. Experimental results demonstrate that the system exhibits leading photon sensitivity and high-speed communication performance. It achieves a post-decoding bit error rate (BER) better than 10 −7 at an effective information transmission rate of up to 500 Mbps, with an incident sensitivity of 1.78 photons/bit and a detection sensitivity of 0.97 photons/bit. Furthermore, the system is capable of maintaining closed-loop BER performance within a dynamic range of at least 1.8 dB above this incident signal level, highlighting the advanced performance and reliability of the entire system. Additionally, the system supports 10 G/40 G ethernet interfaces, enabling inter-board timestamp data transmission from the time-to-digital converter (TDC) to the FPGA at rates between 300 million and 1.2 billion timestamps per second, indicating potential for rapid real-time hardware implementation. This demonstration system can provide insights for the design of future high-speed real-time photon counting communication systems.