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Advances of chip-scale atomic clock in Peking University

The authors are developing chip-scale atomic clocks (CSACs) based on the 85Rb coherent population trap (CPT) transition. As an intermediate milestone, we have developed a miniature atomic clock prototype. In this paper, we report on the design combing the miniature physics part, low-power digital control circuits and low-power microwave system, and the process that enable an atomic clock to be made with an overall size of 20 cm3 volume, power consumption about 400 mWatts, and an Allen Deviation at 100 s of 2.9E-11.