Fig. 1. Structure diagram of multi-system compatible coherent detection device for satellite laser communications

Fig. 2. Constellations of OOK and BPSK for coherent reception of space laser communication. (a) OOK constellation; (b) BPSK constellation without elimination of carrier phase; (c) BPSK constellation after elimination of carrier phase (simulated signal-to-noise ratio is 20 dB)

Fig. 3. Theoretical relationship between BER and received power of OOK and BSPK coherent reception with communication rate of 1 Gbit/s

Fig. 4. Structure diagram of measurement experiment for optimal power of local oscillator light

Fig. 5. Relationship between signal-to-noise ratio and quarter of local oscillator light power

Fig. 6. I and Q signals of coherent OOK

Fig. 7. Coherent OOK baseband signal recovered by proposed algorithm and its eye diagram

Fig. 8. Block diagram of offline processing flow

Fig. 9. I and Q signals of coherent BPSK

Fig. 10. Waveform of coherent BPSK after carrier recovery. (a) Real part of the signal; (b) imaginary part of the signal

Fig. 11. Measured and theoretical curves of OOK and BPSK coherent receiving BER and receiving power with communication rate of 1 Gbit/s. (a) OOK; (b) BPSK