Fig. 1. Application scenario diagram of multi-service transmission system based on FSO and SMF hybrid link

Fig. 2. Structure diagram of bidirectional dual-output multi-service transmission system

Fig. 3. Electrical spectrum and constellation diagram of the downlink transmission signal. (a) 16PSK signal at 10 GHz; (b) 4QAM-OFDM signal at 60 GHz

Fig. 4. Electrical spectrum, constellation and eye diagrams of the uplink transmission signal. (a) Electrical spectrum and constellation diagram of 16QAM signal at 20 GHz; (b) electrical spectrum and eye diagram of OOK baseband signal

Fig. 5. Relationship between downlink EVM value and received optical power, as well as the constellation diagrams of corresponding points. (a) 16PSK signal at 10 GHz; (b) 4QAM-OFDM signal at 60 GHz

Fig. 6. Relationship between uplink EVM and BER values with received optical power, as well as constellation and eye diagrams of corresponding points. (a) 16QAM signal at 20 GHz; (b) OOK baseband signal

Fig. 7. Relationship between EVM value of the downlink transmission signal and received optical power. (a) 16PSK signal at 10 GHz; (b) 4QAM-OFDM signal at 60 GHz

Fig. 8. Relationship between EVM or BER value of various output signals and FSO transmission distance under different weather conditions. (a) 16PSK signal; (b) 4QAM-OFDM signal; (c) 16QAM signal; (d) OOK signal