针对基于马赫-曾德干涉仪结构的硅基光调制器中非线性电光响应的问题, 采用包含PN结非线性调制损耗和非线性折射率变化的模型, 通过数值仿真方法, 研究了上下两臂对称和不对称两种情况下, 调制损耗对硅基光调制器非线性的影响.对比考虑调制损耗和忽略调制损耗的模型, 发现在常规大信号情况下, 当光调制器偏置相位为0时, 调制损耗使得三次谐波增强, 四次谐波减弱；当光调制器偏置相位为π/2时, 调制损耗使得二次和四次谐波增强；而在小信号情况下, 三次和四次等高次谐波不明显, 在光调制器偏置相位为0时, 调制损耗在光调制器上下两臂不对称情况下增加了基频分量串扰；在光调制器偏置相位为π/2时, 调制损耗的影响主要表现为增加了二次谐波分量.

Aiming at the nonlinear electro-optical response in the Mach-Zehnder Interferometer (MZI)-based silicon modulator, the model with the nonlinear modulating loss in PN junction and the nonlinear refractive index changing was utilized, and the influence of modulating loss on the silicon modulator was investigated for two cases: symmetric arm or asymmetric arm in the MZI-based modulator. By taking account of the modulating loss in the model, the results can be obtained that in the condition of large signal, the third order harmonic component is enhanced and the fourth order harmonic component is reduced when the bias phase of the optical modulator is 0, and the second order and fourth order harmonic component are all enhanced when the bias phase of the optical modulator is π/2. While in the condition of small signal, the high order harmonic components, such as the third order and fourth order harmonic components, are not obvious, and the crosstalk of fundamental frequency is enhanced by the modulating loss when the bias phase of the optical modulator is 0 and two arms in the modulator are asymmetric, the second order harmonic component is enhanced by the modulating loss when the bias phase of the optical modulator is π/2.