非线性傅里叶变换及其在光通信和超短脉冲表征领域的应用  

Nonlinear Fourier Transform and Its Applications in Optical Communications and Pulse Characterizations

作　　者：陈方林 曹怡青 王雨田 唐霞辉[1] 唐明[1] 付松年 赵鹭明 Chen Fanglin;Cao Yiqing;Wang Yutian;Tang Xiahui;Tang Ming;Fu Songnian;Zhao Luming(Optics Valley Laboratory Whan National Laboratory for Optoelectrouics,School of Optical aud Electrouic Iuformation,Huazhong Unicersity of Science and Technology,Wuhan 430074,Hubei,China;Adcannced Institute of Photonics Technology,School of Information Engineering,Guangdong University of Technology,Guanngzhou 510006,Guagdong,China)

机构地区：[1]华中科技大学光学与电子信息学院武汉光电国家研究中心光谷实验室,湖北武汉430074 [2]广东工业大学信息工程学院先进光子研究院,广东广州510006

出　　处：《中国激光》2022年第12期232-251,共20页Chinese Journal of Lasers

基　　金：中国-波兰第38届科技例会交流项目(6);华中科技大学自主创新研究基金(HUST:2020kfyXJJS007)。

摘　　要：非线性傅里叶变换可以将信号转换为包括连续谱和离散谱的非线性谱,其中离散谱的本征值位于复平面的上半部分。通过非线性傅里叶变换,信息被编码到信号的非线性谱中,可以实现信号和非线性积累的有效区分,从而解决标准单模光纤中出现的非线性传输损伤。同时,作为新型的信号分析工具,非线性傅里叶变换还可以用于分析光纤激光器中的孤子脉冲。对于纯孤子,其非线性谱仅包含离散谱,离散谱中的本征值对应于孤子的特征,其实部和虚部分别对应于孤子的频率和幅值。非线性傅里叶变换技术为激光动力学的研究提供了新视角,从脉冲的全场信息得到脉冲的非线性谱,进而根据不同的本征值分布分离孤子和连续波背景,就可以实现纯孤子的产生。本文综述了非线性傅里叶变换的原理及其在光通信和光纤激光器领域的应用,并介绍了基于非线性傅里叶变换的“孤子蒸馏”技术。Significance Nonlinear Fourier transform (NFT)can convert a signal into a nonlinear spectrum,including continuous spectrum and discrete spectrum,where the eigenvalues are located in the upper half of the complex plane.With the approach of NFT,information is encoded into the nonlinear spectrum of a signal,which can effectively address the nonlinear transmission impairments arising in standard single-mode fiber.At the same time,as a new effective signal processing tool,NFT can be used to analyze pulses in fiber lasers.For a pure soliton,its nonlinear spectrum only contains the discrete spectrum.The eigenvalues in the discrete spectrum can then be used to characterize soliton pulses,wherein the real and imaginary parts refer to the frequency and amplitude of soliton pulses,respectively.This methodology provides a new perspective for the study of laser dynamics.The soliton and continuous wave background can be separated based on their different eigenvalue distributions after the obtainment of full-field information of pulses.We summarize the principle of NFT and its applications in the field of optical communications and fiber lasers,specifically the“soliton distillation”technology based on NFT.In optical fiber communication systems,there are transmission impairments such as loss,dispersion,and nonlinearity.Loss and dispersion can be compensated by optical amplification and dispersion compensation technology.Pulse broadening and distortion caused by nonlinear effects related to optical pulse intensity have,however,become the main factors limiting the system communication capacity improvement.As a powerful mathematical tool,NFT can effectively solve the problem of lightwave propagation in a nonlinear medium such as an optical fiber.Recently,a new framework of optical fiber communication systems based on NFT has begun receiving extensive attention.NFT can decompose a signal into a continuous spectrum (nonsoliton component)and discrete spectrum (soliton component),which are considered nonlinear spectra.With this met

关 键 词：傅里叶光学 光通信 非线性傅里叶变换 耗散孤子 光纤激光器 

分 类 号：TN209[电子电信—物理电子学]