中文摘要：

设计了一种新型改进结构马赫-曾德尔干涉（MZI）电光开关,即在传统结构MZI电光开关中,使用一个相位发生器（PGC）取代一个3 dB耦合器。给出了改进器件的模型和工作原理,导出了振幅传输矩阵,分析了相移补偿原理和开关条件,优化了结构参数,模拟了传输功率、输出功率、输出频谱、插入损耗、串扰等特性。仿真结果表明,所设计器件的开关电压为2.445 V,开关时间为18.1 ps,拓展后的输出频谱为110 nm,工作波长在1492≤λ≤1602 nm范围内,器件的插入损耗小于2.24 dB,串扰小于-30 dB。设计结果与基于光束传播法（BPM）的Optiwave软件模拟结果吻合较好。

英文摘要：

By replacing the first 3 dB coupler with a phase generating coupler（PGC） in the conventional Mach-Zehneder interferometer（MZI） electro-optic switch,a novel improved switch is designed.The structural model is presented,and the principle is described.The expressions of the amplitude transfer matrices are derived,and the compensating principle of the phase shift and the switching condition are analyzed.The parameters are optimized,and the characteristics are simulated,involving the propagation power,output power,output spectrum,insertion loss and crosstalk.Simulation results for the designed device show that,the push-pull switching voltage is 2.445 V,the switching time is 18.1 ps,the pass-band of the output spectrum can be increased to 110 nm,and the insertion loss and crosstalk are less than 2.24 dB and-30 dB,respectively,within the wavelength range from 1492 to 1602 nm.Our simulation results agree well with those of the Optiwave software based on the beam propagation method（BPM）.