基于线性啁啾光栅简化设计和频率-时间映射理论的任意波形产生技术研究  

Arbitrary Waveform Generation Based on Simple Design of Linearly Chirped Fiber Bragg Grating and Frequency-to-Time Mapping

作　　者：李敏[1] 牟宏谦 王目光[1] 韦新航 官祥帅 Li Min;Mu Hongqian;Wang Muguang;Wei Xinhang;Guan Xiangshuai(Key Laboratory of All Optical Network and Advanced Telecommunication Network,Ministry of Education,Institute of Lightwave Technology,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学光波技术研究所全光网络与现代通信网教育部重点实验室,北京100044

出　　处：《中国激光》2021年第20期85-98,共14页Chinese Journal of Lasers

基　　金：国家自然科学基金(61775015);中央高校基本科研业务费专项资金资助(2019JBM010)。

摘　　要：基于频率-时间映射理论,提出一种简单、全光纤任意波形产生方法。该方法简化了具有任意反射谱的线性啁啾光栅设计方法,结合啁啾光栅的色散特性,能够实现用户定义的任意波形脉冲信号。利用由传输损耗公式推导的折射率调制幅度与光栅反射率的关系,可实现具有任意形状反射谱的啁啾光栅的逆向设计;微调折射率调制幅度伸缩因子和折射率调制顶点的归一化光谱位置可优化反射谱形状,在保证高反射率的情况下(≥90%),设计误差可降低至10%以下。阐明啁啾光栅色散特性引入的频率-时间映射关系,将设计的光谱形状映射到时域波形,改变光栅设计参数,可灵活控制输出脉冲的形状和脉宽。基于Matlab和Optisystem仿真软件,以常用重要波形(三角形、锯齿形、矩形、梯形、高斯型、抛物型脉冲)为例验证了系统的可行性。该方法简单灵活,对任意波形产生和应用研究具有一定的参考价值。Objective The arbitrary waveform generator(AWG)has been widely utilized in wireless communications,radar systems,and signal processing due to its benefits of high frequency and large bandwidth.More emphasis has been paid to creating commonly used pulses(triangular,sawtooth,rectangular,parabolic,and Gaussian).Conventional AWG,based on electronics,has a sampling rate up to a few tens of GHz,whereas photonic-assisted AWG,which can break the speed and bandwidth limits of electronics,has become a topic of interest.Compared with other photonic-assisted AWGs,spectral shaping and frequency-to-time mapping can realize arbitrary waveforms with the advantages of low loss,strong system reliability,and easy integration.To further simplify the AWG system based on spectral shaping and frequency-to-time mapping,linearly chirped fiber Bragg grating(LCFBG)is operated as both the spectral shaper and dispersion device for the generation of frequency-chirped and phase-coded pulses.For the generation of arbitrary waveforms,it is difficult to employ CFBG as both the spectral shaper and dispersion device because of the complicated design method and fabrication process of CFBG with an arbitrary spectral response.This paper proposes a simple allfiber method for arbitrary waveform generation based on the frequency-to-time mapping.The design scheme of CFBG with an arbitrary spectral response is simplified,and with the assistance of the dispersion characteristic of CFBG,the user-defined arbitrary waveform can be achieved accordingly.Methods This study proposes an all-fiber and straightforward method for arbitrary waveform generation based on frequency-to-time mapping.First,the design scheme of LCFBG with an arbitrary spectral response is simplified.The relationship between refractive index modulation amplitude and grating reflectivity is derived from the transmission loss formula.By adjusting the amplitude scaling factor M;and the normalized position of the spectral vertex of the refractive index modulation M;,the reflective spectral respons

关 键 词：光通信 任意波形产生 频谱整形 频率-时间映射 啁啾光栅 三角形滤波器 

分 类 号：TN929.11[电子电信—通信与信息系统]