应用并行MZM降低光载OFDM系统的非线性失真

Reduction of Signal Nonlinear Distortion in CO-OFDM Systems By Dual-parallel Mach-Zehnder Modulators

摘要:

针对传统马赫－曾德尔调制器（MZM）在光载正交频分复用（OFEM）系统中的非线性失真问题，提出了一种新的并行MZM结构，该结构由主调制器和起补偿作用的子调制器组成。理论分析与仿真表明：通过设计调制器电极长度与输入光功率，使得相位误差衰减因子小于１，此时并行MZM的非线性失真小于传统MZM。在相同调制指数下，并行MZM对应的星座图更加收敛，但随着调制指数的增加而逐渐发散。

Abstract:

A new dual-parallel Mach-Zehnder modulator (MZM) consisting of a primary modulator and a compensative sub-modulator was applied to reduce the signal nonlinear distortion in Coherent Optical OFDM (CO-OFDM) systems. Analysis and simulation results show that the signal nonlinear distortion of dual-parallel MZM is less than that of conventional MZM when phase error attenuation factor is less than 1 by designing modulator electrode length and input optical power. With the same modulation index, the constellation diagram of dual-parallel MZM is much more convergent than that of conventional MZM. While with the increase of modulation index, the constellation diagram gradually becomes divergent.