Fig. 1. Block diagram of encryption-modulation integrated optical communication system based on optical XOR logic gate using DD-MZM

Fig. 2. Implementation schematic diagram of encryption-modulation integrated system. (a) Phase offset of upper arm; (b) phase of original signal in upper arm; (c) phase of original signal in upper arm after offset; (d) phase offset of lower arm; (e) phase of original signal in lower arm; (f) phase of original signal in lower arm after offset; (g) result of vector superposition of optical signals of two arms; (h) result of vector superposition of optical signals of two arms after optimization

Fig. 3. Experimental setup and results. (a) Experimental block diagram of encryption-modulation integrated system; (b) prototype of encryption-modulation integrated transmitter; (c) temporal waveforms of signals; (d) eye diagram of encrypted signal

Fig. 4. Signal extinction ratios of encryption-modulation integrated system and traditional OOK system under different transmission distances