占空比可调的奈奎斯特脉冲产生  

Nyquist pulse generation with adjustable duty cycle

作　　者：王辉 李佳康[1,2] 贾东方 葛春风[1,2] 王肇颖[1,2] 杨天新[1,2] WANG Hui;LI Jiakang;JIA Dongfang;GE Chunfeng;WANG Zhaoying;YANG Tianxin(School of Precision Instrument and Optoelectronics Engineering,Tianjin University,Tianjin 300072,China;Key Laboratory of Optoelectronic Information Technology,Ministry of Education,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学精密仪器与光电子工程学院 [2]天津大学光电信息技术教育部重点实验室

出　　处：《光电子．激光》2023年第1期1-9,共9页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61975145)资助项目。

摘　　要：奈奎斯特(Nyquist)脉冲在光通信、微波光子学、光存储和全光采样等领域中有着重要应用价值。为适应不同的应用场合对Nyquist脉冲的占空比的具体要求,提出了一种基于光谱展宽和啁啾补偿的占空比可调的Nyquist脉冲产生方案。首先,利用相位调制器(phase modulator,PM)作为时间透镜,将强度调制器(intensity modulator,IM)输出的平顶光脉冲变换到频域光谱展宽的平坦光频梳;然后,通过标准单模光纤(standard single-mode fiber,SSMF)补偿相位调制引入的近线性啁啾,得到脉宽压缩的无啁啾短脉冲;最后,通过中心波长和带宽可调的光滤波器滤波实现了Nyquist脉冲占空比的连续可调。通过数值仿真实验,在10 GHz的射频信号频率下,获得了周期为100 ps,脉宽为4.0—12.6 ps,占空比在4.0%—12.6%之间可调的Nyquist脉冲,且脉冲的滚降系数较低,在0—0.127之间,与理想Nyquist脉冲的均方根误差为0.16%—0.58%。结果表明,该方案能够实现占空比灵活可调的Nyquist脉冲的产生。Nyquist pulses have important applications in the fields of optical communication,microwave photonics,optical storage and all-optical sampling.To meet the specific requirements for the duty cycles of Nyquist pulses in different applications,a scheme for generating Nyquist pulses with adjustable duty cycles based on spectral broadening and chirp compensation is proposed.First,using the phase modulator(PM)as a time lens,the flat-top optical pulse generated by the intensity modulator(IM)is transformed into a flat optical frequency comb with spectral broadening in the frequency domain;Then,the near-linear chirp introduced by the phase modulation is compensated by standard single-mode fiber(SSMF),resulting in a pulse-width compressed short pulse without chirp;Finally,continuous adjustment for the duty cycle of Nyquist pulses is achieved using an optical filter with adjustable center wavelength and bandwidth.Nyquist pulses with a period of 100 ps,a pulse width of 4.0 ps to 12.6 ps and an adjustable duty cycle of 4.0%to 12.6%are obtained at the radio frequency of 10 GHz by numerical simulation.The roll-off factors are relatively low,ranging from 0 to 0.127,and the root mean square errors with the ideal pulses are 0.16%—0.58%.The results show that this scheme can realize the generation of Nyquist pulses with flexible and adjustable duty cycles.

关 键 词：奈奎斯特脉冲 光学频率梳 光谱展宽 啁啾补偿 

分 类 号：O436[机械工程—光学工程]