Systematic Analysis and Design of Lunar–Earth Optical Communication System Based on Phase-Sensitive Amplifier

The development of the Lunar–Earth space urgently requires a miniaturized space laser communication system with a high speed and high sensitivity. However, traditional photon-counting communication and coherent communication technologies face challenges in meeting these two core requirements, forming a critical bottleneck that limits the performance enhancement of long-distance lunar communication links. To address this issue, this paper comprehensively analyzes the power attenuation, wavelength drift, and phase jitter over the Lunar–Earth communication channel and proposes a system improvement method that integrates a phase-sensitive amplifier (PSA) with coherent communication technologies. Additionally, a comprehensive system simulation model is established to evaluate the proposed approach. The simulation results demonstrate that the system can effectively adapt to the Lunar–Earth communication scenario. Utilizing QPSK-modulated signals, the system achieves a communication rate of up to 10 Gbps, with receiving sensitivities of 0.7 photons per bit. This approach effectively meets the demand for high data rates and high sensitivity, thus providing a technical pathway for the engineering implementation of ultra-long-distance space laser communications.