Fig. 1. Scheme of incoherent OOK and coherent BPSK multiplexed space laser communication

Fig. 2. Relationship between output optical power of intensity modulator and bias voltage

Fig. 3. Relationship curve between optical filter bandwidth and incoherent OOK SNR overhead

Fig. 4. Relationship curve between intensity modulation bias voltage deviation and incoherent OOK Q overhead

Fig. 5. Relationship curve between received optical power and BPSK SNR overhead (0.2 nm and 20 nm optical filter bandwidth)

Fig. 6. Relationship curve between received optical power and BPSK SNR overhead (with or without common noise)

Fig. 7. Actual experimental setup

Fig. 8. Relationship curve between optical filter bandwidth and incoherent OOK communication performance. (a) Logarithmic BER; (b) Q value

Fig. 9. Eye diagrams of incoherent OOK receiving signal under different optical filtering bandwidths. (a) 0.2 nm; (b) 0.6 nm

Fig. 10. Relationship curve between intensity modulation bias voltage and incoherent OOK logarithmic BER

Fig. 11. Relationship curves between received optical power and BPSK communication performance. (a) BER; (b) SNR

Fig. 12. Connection method of balanced detector and high-speed AD

Fig. 13. Relationship curve between common noise and BPSK BER (below 10^-14 indicates no error)