说明：  1. 针对推挽结构MZ-LiNbO3调制器； （1）通过MATLAB编程画出输出电场、输出功率传递函数随外加波导两臂相位差的变化曲线； （2）确定相位调制器、强度调制器的偏置电压； （3）假设理想条件下强度调制器消光比为20dB，通过MATLAB编程画出消光比曲线随3dB耦合器分光比的变化。（分光比R=0.45:0.05:0.55）
(1. For push-pull MZ-LiNbO3 modulator; (1) The curves of the output electric field and the output power transfer function with the phase difference between the two arms of the external waveguide are drawn by MATLAB programming. (2) Determine the bias voltage of phase modulator and intensity modulator; (3) Assuming that the extinction ratio of intensity modulator is 20 dB under ideal conditions, the extinction ratio curve of intensity modulator varies with the splitting ratio of 3dB coupler by MATLAB programming. (Spectrum ratio R = 0.45:0.05:0.55))