可搬运铷喷泉原子钟全自动激光稳频系统  

Automatic Laser Frequency Stabilization System for Transportable 87Rb Fountain Clock

作　　者：吉经纬 程鹤楠 张镇 刘亢亢[1] 项静峰 任伟[1] 李琳[1] 吕德胜[1] Jingwei Ji;Henan Cheng;Zhen Zhang;Kangkang Liu;Jingfeng Xiang;Wei Ren;Lin Li;Desheng Lü(Key Laboratory of Quantum Optics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海光学精密机械研究所量子光学重点实验室,上海201800 [2]中国科学院大学,北京100049

出　　处：《光学学报》2020年第22期157-163,共7页Acta Optica Sinica

基　　金：中国科技部仪器项目(2013YQ09094304);国家自然科学基金(11034008)。

摘　　要：能够长期自主运行的稳频激光器是喷泉原子钟连续工作的基础。基于铷原子喷泉钟中的780 nm商用半导体激光器,利用嵌入式系统设计了一个长期全自动稳频系统。该系统具有自动识别铷饱和吸收谱线的目标峰、长期锁定频率与意外失锁后的快速重锁的功能。提出了一种动态调整工作点的方法。在激光器长期运行过程中,受温度、湿度和器件老化等因素的影响,目标工作点会随时间发生变化,所提方法可解决该问题。利用该方法,激光器的稳频系统不易失锁,即使失锁也可以快速重新锁回。将所提稳频系统成功应用于可搬运铷喷泉原子钟中,铷喷泉原子钟在搬运后能够快速投入工作,激光频率的长期锁定时间可达一个月以上。激光频率相对于铷饱和参考谱线的频率长期稳定度约为2.3×10-13,可搬运铷喷泉原子钟的长期稳定度在搬运前后均达到了10-16量级。A frequency stabilized laser capable of long-term autonomous operation is the basis for the continuous operation of an atomic fountain clock.In this paper,based on a 780 nm commercial external cavity diode laser used in the 87Rb fountain clock,we develop a long-term automatic frequency stabilization system by using an embedded system.The proposed system can automatically identify the target peak in the 87Rb saturated absorption spectrum,stabilize the laser frequency for a long time and quickly re-lock it after an accidental loss of lock.In addition,we develop a method for dynamically adjusting the operating point.The target operating point changes with time because the influences of temperature,humidity,device aging,and other factors during the long-term operation of the laser.Based on this method,the laser frequency stabilization system makes lock loss rarely occur,and easily re-locks even if lock loss happens.The proposed frequency stabilization system has been successfully applied to our transportable 87Rb fountain clock.The clock can operate normally soon after transport and the long-term stabilization time of laser frequency can reach more than one month.The long-term stability of laser frequency relative to the 87Rb saturated absorption spectrum is about 2.3×10-13 and the long-term stability of the transportable 87Rb fountain clock before and after transport is always at the magnitude of 10-16.

关 键 词：激光器 激光冷却 喷泉原子钟 自动稳频 稳定度 

分 类 号：TN284.4[电子电信—物理电子学]