高线性度电光调制器研究进展  

Research Progress on High-Linearity Electro-Optical Modulators

作　　者：刘子溪 曾成 夏金松 Liu Zixi;Zeng Cheng;Xia Jinsong(Wuhan National Laboratory for Optoelectrouics Huazhong University of Science and Technology,Wuhan 430074,Hubei,China)

机构地区：[1]华中科技大学武汉光电国家研究中心,湖北武汉430074

出　　处：《中国激光》2022年第12期196-216,共21页Chinese Journal of Lasers

基　　金：国家重点研发计划(2019YFB2203501);国家自然科学基金(61835008,62175079)。

摘　　要：高线性度电光调制器主要用于解决微波光子系统中电信号到光信号转化时信号非线性失真的问题,微波光子链路的性能会受到电光调制器线性度的影响。本文首先分析了调制器产生非线性的原理,然后从电学域和光学域两方面概述了国内外提高调制器线性度的研究进展,并着重介绍了MZM串/并联法与微环辅助法的原理与研究进展,最后概述了薄膜铌酸锂在高线性度调制器上的应用,并对薄膜铌酸锂高线性度调制器的应用前景进行了展望。Significant Microwave photonic(MWP)systems generate,manipulate,transmit,and measure high-speed radio-frequency(RF)signals in the optical domain.Converting RF signals in the optical domain improves the signal-processing bandwidth and speed and reduces power consumption by complex electronic systems.Optical modulation is the most important step in converting microwave signals into optical signals in all MWP systems.This usually determines the performance of the whole system,including its bandwidth,system loss,linearity,and dynamic range.Nonlinear distortion is introduced mainly by the nonlinearity of the Mach-Zehnder electro-optical modulator(MZM)used in MWP systems.The modulation curve of a typical MZM takes the form of a cosine function.To achieve the approximate linearity of the modulation,the working point of the modulator is fixed at an orthogonal offset point,where it cannot fulfill the requirements of a microwave photonic link.A stable and efficient MWP system requires the modulator to exhibit a low noise figure,i.e.,less than 10 dB,and a high spurious free dynamic range(SFDR)exceeding 120 dB·Hz^(2/3).The SFDRs of a typical silicon MZM and a microring modulator are approximately 97 dB·Hz^(2/3)and 84 dB·Hz^(2/3),respectively.Therefore,a high-linearity electro-optical modulator is urgently needed.Progress Two options exist for improving the linearity of an electro-optical modulator:the electrical and optical domains.In the electrical domain,one method is to use electronic predistortion.Introducing arcsine predistortion into the RF signal compensates for the cosine modulation.Another method is to employ electronic post compensation.This method uses digital sampling at the output to remove the distortion term produced by the modulator.These methods in the electrical domain do not fundamentally improve the linearity of the modulator,and they require an accurate control of the introduced distorted signal and additional high-speed electronic devices.With increasing working time,the MZM itself experiences unstabl

关 键 词：光学器件 高线性度 电光调制器 微波光子器件 薄膜铌酸锂 无杂散动态范围 

分 类 号：O436[机械工程—光学工程]