基于1560 nm外腔式激光器的拉曼光锁相技术  

Phase locking technology for Raman laser system based on 1560 nm external cavity lasers

作　　者：王凯楠 程冰 周寅 陈佩军 朱栋 翁堪兴 王河林[1] 彭树萍 王肖隆 吴彬[1] 林强[1] Wang Kai-Nan;Cheng Bing;Zhou Yin;Chen Pei-Jun;Zhu Dong;Weng Kan-Xing;Wang He-Lin;Peng Shu-Ping;Wang Xiao-Long;Wu Bin;Lin Qiang(Zhejiang Provincial Key Laboratory of Quantum Precision Measurement,College of Science,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]浙江工业大学理学院,浙江省量子精密测量重点实验室,杭州310023

出　　处：《物理学报》2021年第17期17-24,共8页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFC0601602);国家自然科学基金(批准号:51905482,61727821,61875175,11704334,51905482);中国自然资源航空物探遥感中心项目(批准号:DD20189831)资助的课题.

摘　　要：拉曼光产生技术是量子精密测量领域的一个重要研究内容,是冷原子重力仪、冷原子陀螺仪等量子惯性传感器的关键技术.对于铷87原子,需要两束频差6.834 GHz且相位稳定的780 nm激光来产生拉曼光.基于两台外腔式780 nm激光器,并利用光学锁相环技术可以产生拉曼光,但系统复杂、环境适应性不强.基于内腔式1560 nm激光器,通过倍频和电光调制技术也可以产生拉曼光,虽然系统简单、环境适应性强,但测量性能受边带效应影响.受限于内腔式激光器的线宽及反馈带宽性能,一般无法利用光学锁相环方法来产生拉曼光.鉴于此,本文基于两台新型外腔式1560 nm激光器和自制锁相电路系统,实现了一套低相噪的拉曼光系统,相位噪声功率谱在1-10 kHz频段低至-95 dBc/Hz.通过与780 nm双激光器及混合双激光器锁相性能进行比较,发现该方案略具优势.此外,通过分段积分的方法分析了该锁相性能对冷原子干涉仪相位噪声的影响.本文实验结果为研制小型化、外场适用的拉曼光系统提供了一种方案.The technology of generating Raman laser is not only an important research content in the field of quantum precision measurement,but also a core technology of quantum inertial sensors such as cold atom gravimeter,gyroscope.For 87Rb atoms,two 780-nm lasers with a frequency difference of 6.834 GHz and a stable phase are needed to generate Raman light.Raman lasers can be generated by optical phase-locked loops of two 780-nm narrow linewidth external cavity tunable semiconductor lasers(ECDL).But the system thus developed is complicated in structure and very poor in environmental adaptability.The other method to generate Raman laser is based on intracavity 1560-nm laser with frequency doubling and electro-optic modulation technology.This system is simple in structure and strong in environmental adaptability,but it will introduce sideband effects and cannot achieve phase lock due to the limit by the linewidth and feedback bandwidth performance of the laser.In view of this,based on two new 1560-nm external cavity lasers and a home-made phase-locked circuit,in this paper the phase lock of the laser is achieved,and a Raman laser with low phase noise is obtained.The phase noise of beat note signal is as low as–95 dBc/Hz at the Fourier frequency in a range from 1 kHz to 10 kHz.A comparison of this system with the phase-locked performance of the 780-nm dual laser and the hybrid dual laser shows that this scheme has a slight advantage.In addition,the effect of the phase-locking performance on the phase noise of the cold atom interferometer through the method of piecewise integration is analyzed in this work.The experimental results given in this work provide a scheme for developing a miniaturized Raman optical system suitable for external fields.

关 键 词：冷原子 原子干涉仪 拉曼激光 

分 类 号：TN248[电子电信—物理电子学]