Research On Generation Technology Of Carrier-Suppressed Single Sideband Optical Signal Based On Electro-Optical External Modulation

Single sideband optical signals can not only avoid the periodic power fading of optical-carrying microwave and millimeter-wave signals in optical fiber link transmission power caused by optical fiber dispersion,but also have the advantages of high frequency band utilization,and are widely used in optical communication,military and high-precision measurement field,etc.The Electro-optic modulator is the core device for generating single sideband signal,and its optimal bias point will drift due to its own material characteristics,which affects the quality of the single sideband signal generated by modulation and the stability of signal transmission in the optical fiber.Therefore,in this paper,the technology of generating carrier-suppressed single-sideband optical signals through electro-optical modulator is studied,and an electro-optic modulator control system based on DSP for single-sideband signal generation is designed,which realizes that the electro-optic modulator can modulate stably for a long time to generate carrier suppressed single sideband signals.The main research contents of this paper are as follows:1.The working principle of electro-optical modulator is studied,and the working principle of electro-optical modulator to generate single sideband optical signal is deduced and analyzed.Finally,the simulation verification is carried out by using Opti System.2.The bias voltage control scheme of electro-optic modulator for single sideband optical signal generation is proposed,and a preliminary calibration scheme is designed to quickly confirm the bias voltage of electro-optic modulator operating point without adding RF signal.By combining the bias voltage control method of electro-optic modulator based on pilot signal,an automatic control scheme of iterative cyclic bias voltage in time sequence is proposed.3.An electro-optical modulator control system based on DSP for single sideband optical signal generation is designed,and the software and hardware of the control system are analyzed and designed.Finally,the reliability and accuracy of the initial calibration scheme of the system and the feasibility of the system to control the electro-optical modulator to modulate the output carrier-suppressed single sideband optical signal stably for a long time are verified through building the system and testing the performance.