Advances of chip-scale atomic clock in Peking University

The authors are developing chip-scale atomic clocks (CSACs) based on the
⁸⁵
Rb 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 cm
³
volume, power consumption about 400 mWatts, and an Allen Deviation at 100 s of 2.9E-11.