Fig. 1. Schematic diagram of balanced homodyne detection

Fig. 2. Relation diagram of detection deviation with local vibration noise and unbalance degree

Fig. 3. AC output noise model of BHD

Fig. 4. Schematic diagram of the balanced homodyne detector

Fig. 5. Schematic of the experimental setup for measuring performance of photodetector

Fig. 6. BHD performance test results. (a) Performance results of the BHD developed in the 2-500 Hz frequency band; (b) Performance test results of the developed BHD in 0.05 mHz-1 Hz band. The sampling rate of the high-precision multimeter is 2 S/s, the sampling time is 5 h, and the data overlap rate of LPSD processing is 0.3