中圖分類號(hào)： TB939 文獻(xiàn)標(biāo)識(shí)碼： A DOI：10.16157/j.issn.0258-7998.200805 中文引用格式： 王淼兒，姚燕. 一種CPT銫原子鐘控制系統(tǒng)的設(shè)計(jì)[J].電子技術(shù)應(yīng)用,，2020,，46(12)：57-60，66. 英文引用格式： Wang Miaoer,，Yao Yan. Design of control system for a CPT Cesium atomic clock[J]. Application of Electronic Technique,，2020，46(12)：57-60,，66.
Design of control system for a CPT Cesium atomic clock
Wang Miaoer,，Yao Yan
Collage of Metrology and Testing Engineering，China Jiliang University,，Hangzhou 310018,，China
Abstract： The realization of coherent population trapping(CPT) atomic clock with miniaturized, low-power is of great significance for its applications in the fields of precision measurement such as communication and position. The peripheral circuit controlling accurate frequency and laser output is the key technology to achieve coherent population trapping atomic clock. A peripheral control system of CPT Cesium atomic clock is developed in this paper. The system uses two levels for fine-tuning and coarse-tuning to drive the VCSEL laser to work, which is more accurate than single current adjustment and uses phase-locked loop circuit to generate modulated microwave signal. PIN diodes are used to adjust the microwave power attenuation in order to realize the adjustment of microwave power. In the meanwhile, software modulation and demodulation methods is applied to replace traditional hardware modulation and demodulation circuits, which saves circuit logic resources.The testing results show that the output of the microwave power reaches -3.33 dBm when the microwave frequency is 4.596 267 GHz. The phase noise of the radio frequency circuit is better than -80 dBc/Hz under the frequency offset of 1 kHz which has better capability.
Key words : coherent population trapping,；atomic clock；control system,；modulation and demodulation,；phase noise
0 引言
1967年國(guó)際計(jì)量大會(huì)將時(shí)間單位秒定義為原子秒，時(shí)間秒是基于銫原子(133Cs)在其基態(tài)的超精細(xì)能級(jí)間躍遷頻率(9 192 631 770 Hz)[1],。傳統(tǒng)原子鐘精確度很高,，但由于其體積很大，應(yīng)用范圍較小,，1976年ALZETTA C等人發(fā)現(xiàn)粒子數(shù)相干布居囚禁(Coherent Population Trapping,，CPT)現(xiàn)象[2]，這使原子鐘系統(tǒng)向微型化發(fā)展成為可能[3],。隨著科技發(fā)展,，精確定時(shí)在水下石油勘探、移動(dòng)網(wǎng)絡(luò)通信和全球定位系統(tǒng)等領(lǐng)域的應(yīng)用,，推動(dòng)了緊湊型,、高性能原子鐘的發(fā)展[4]，所以研制具備小型化,、低相位噪聲,、低功耗、高頻率穩(wěn)定度的原子鐘具有重要意義,。而原子鐘外圍控制電路作為原子鐘系統(tǒng)重要組成部分,，是實(shí)現(xiàn)精準(zhǔn)頻率輸出的關(guān)鍵。
