微波功率锁定的高性能CPT原子钟频综  

A Power Stabilized Low Noise Frequency Synthesizer for CPT Atomic Clocks

作　　者：温智强 云恩学 孙思宇 杨腾辉 王弼松 王雷刚 罗鑫 许进 孙兵锋 李文兵 郝强 WEN Zhiqiang;YUN Enxue;SUN Siyu;YANG Tenghui;WANG Bisong;WANG Leigang;LUO Xin;XU Jin;SUN Bingfeng;LI Wenbing;HAO Qiang(NTSC,Chinese Academy of Science,Xi’an,Shaanxi 710600,China;University of Chinese Academy of Sciences,Beijing 101408,China;School of Electronics and Information,Northwestern Polytechnical University,Xi’an,Shaanxi 710072,China;Frontier Interdisciplinary College,National University of Defense Technology,Changsha,Hunan 410073,China;Hangzhou Institute of Extremely-Weak Magnetic Field Major National Science and Technology Infrastructure,Hangzhou,Zhejiang 310051,China)

机构地区：[1]中国科学院国家授时中心,陕西西安710600 [2]中国科学院大学,北京101408 [3]西北工业大学电子信息学院,陕西西安710072 [4]国防科技大学前沿交叉学科学院,湖南长沙410073 [5]杭州极弱磁场国家重大科技基础设施研究院,浙江杭州310051

出　　处：《计量学报》2025年第2期267-273,共7页Acta Metrologica Sinica

基　　金：国家自然科学基金(12173043,U1731132)。

摘　　要：相干布局囚禁(CPT)原子钟通过微波调制激光器产生相干双色激光,与原子体系相互作用获得极窄的CPT共振信号,实现本振频率的锁定。因微波调制在光上,省去了微波腔,可以实现原子钟的小型化甚至芯片化。在追求CPT原子钟芯片化同时,其频率稳定度极限也得到深入研究,目前高性能CPT原子钟的频率稳定度已达~2×10^(-13)τ^(-1/2)(τ=1~10000 s)的水平,但由于微波相位噪声及其功率起伏等因素,限制了CPT原子钟性能的进一步提升。针对此瓶颈,设计了1款功率锁定的3.417 GHz低相位噪声微波频综。实验结果表明,在频偏为1 Hz、10 Hz、100 Hz、1 kHz、10 kHz处,频综绝对相噪分别可达到-55.27 dBc/Hz、83.85 dBc/Hz、-110.4 dBc/Hz、-129.5 dBc/Hz、-132.5 dBc/Hz低噪声水平。根据交调效应,其对CPT原子钟1s处的频率稳定度贡献仅为5.0×10^(-14)。该频综链路的残余频率稳定度在1 s时达7.99×10^(-15),并在平均时间万秒以内,优于目前报道最好CPT原子钟指标1个量级以上。锁定后的微波功率稳定性在10000 s时提升了5倍。To achieve high performance coherent population trapping(CPT)atomic clocks,a high-performance frequency synthesizer with power locked is set up.The CPT atomic clocks require a microwave source to modulate laser that generates coherent two-color light which interact with the atomic system to obtain a very narrow linewidth resonance CPT signal and lock in the local frequency.Since its microwave modulation applies to the light,eliminating microwave cavity,CPT clocks can be portable or even chipped.Meanwhile,the short-term frequency stability of high-performance CPT atomic clocks have been demonstrated at the level of~2×10^(-13)τ^(-1/2)(τ=1-10000 s).At this level,the Dick effect or intermodulation effect induced by microwave phase noise become limiting factors for the further improvement of the CPT clocks.For this,we realise a low phase 3.417 GHz noise synthesizer with power-locked.The experimental results show the absolute phase noise of the high performance power locked frequency synthesizer is-55.27 dBc/Hz,-83.85 dBc/Hz,-110.4 dBc/Hz,-129.5 dBc/Hz,-132.5 dBc/Hz at 1 Hz,10 Hz,100 Hz,1 kHz,10 kHz.Its contribution of intermodulation effect to CPT atomic clocks is 5.0×10^(-14),which is analysed at the double low frequency modulation frequency.Residual stability is 7.99×10^(-15) at 1 s,which is more than one order of magnitude higher than the best CPT atomic clocks reported so far in the sampling time rangeτ=1~10000 s.After power locking,the power stability is improved by five times at 10000 s.

关 键 词：计量学 微波频综 相干布局囚禁原子钟 低相位噪声 残余频率稳定度 功率锁定 

分 类 号：TB939[一般工业技术—计量学]