面向空间引力波探测的激光低频段相对强度噪声测试技术  

Measurement Technology of Laser Relative Intensity Noise at Low Frequency for Space-Based Gravitational Wave Detection

作　　者：胡海林 虞逸航 陈迪俊[2] 孙广伟[2] 杨康文 魏芳[2] 杨飞[2] Hu Hailin;Yu Yihang;Chen Dijun;Sun Guangwei;Yang Kangwen;Wei Fang;Yang Fei(School of Optical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai,200093,China;Key Laboratory of Space Laser Communication and Detection Technology,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093 [2]中国科学院上海光学精密机械研究所中科院空间激光传输与探测技术重点实验室,上海201800

出　　处：《中国激光》2023年第23期80-88,共9页Chinese Journal of Lasers

基　　金：科技部重点研发计划(2020YFC2200302,2022YFB3902503);国家自然科学基金(12293033,62275253);中国科学院先导项目(XDB43030401);中国科学院青年创新促进会(YIPA2019251);上海市自然科学基金(21ZR1472100);中科院科研仪器设备研制项目(YJKYYQ20210017)。

摘　　要：面向空间引力波探测对激光光源相对强度噪声的严苛需求,开展了极低相对强度噪声在低频段的测试表征技术研究。构建了基于低噪声光电探测器、高精度数字万用表以及快速傅里叶(FFT)频谱分析仪在低频段0.1 mHz~100 kHz的相对强度噪声测试系统。利用高精度数字万用表及FFT分段Smooth窗函数平滑算法实现对0.1 mHz~0.5 Hz的极低频段内相对强度噪声测试,本底噪声低于-99 dBc/Hz,同时利用低噪声放大器及FFT频谱分析仪测试在1 mHz~100 kHz的相对强度噪声,本底噪声低于-105 dBc/Hz。两种测试手段在1 mHz~0.5 Hz重叠频段内噪声测试结果的一致性验证了所构建测试系统在低频段测试结果的准确性。利用所构建的相对强度噪声测试系统对自研空间引力波探测用平面波导环形腔(NPRO)激光器、商用光纤激光器、商用外腔半导体激光器等多种激光器进行测试评估,并对其噪声成分及来源进行分析。所构建的低频段相对强度噪声测试系统可满足空间引力波探测对激光强度噪声评估的需求,同时也适用于其他低频段精密测量应用的激光光源噪声评估。Objective Combined with current testing technology and spacebased gravitational wave detection requirements,relative intensity noise(RIN)testing must cover the frequency range of 0.1 mHz‒5 GHz.Currently,lownoise spectrum analyzer is used for RIN testing in the higher frequency band of 50 kHz‒5 GHz,and relevant theories and testing methods are relatively mature.OEWaves of the USA SYCATUS of Japan and Shanghai Institute of Optical Machinery have launched corresponding standard test instruments.However,the current test methods in the lowfrequency band are limited in the test band or have high background noise,which cannot fully meet the requirements of RIN low frequency band test and evaluation of laser light source for spacebased gravitational wave detection.It is necessary to develop the low background noise measurement technology and complete and accurate evaluation standard of all low frequency band.Methods In this study,the lowfrequency RIN within 0.1 mHz‒100 kHz is completely tested and characterized,and the background noise of the test system is reduced to form a standardized test system and test algorithm.First,based on lownoise photodetector,highprecision digital multimeter,Labview control data acquisition,and data processing algorithm programming,the test characterization of laser RIN in the frequency band of 0.1 mHz‒0.5 Hz was realized.In the time domain,the highprecision acquisition was conducted using the Labview software to control DMM.The fast Fourier transform(FFT)algorithm was used to analyze the noise characteristics of the collected data in the frequency domain.The smoothing function of different resolutions was used in the calculation of RIN to ensure that the test results in the lowfrequency band are not true,while the serious trailing phenomenon in the highfrequency band was reduced.Besides,frequency domain analysis can be performed immediately upon the completion of the time domain collection,and the data can be stored in real time.Combined with the data of different sampling time,the

关 键 词：单频激光器 噪声测试 相对强度噪声 快速傅里叶变换 空间引力波探测 

分 类 号：O436[机械工程—光学工程]