Design Of Microwave Signal Source Applied To Chip-scale CPT Atomic Clock Of Rb87

The paper focuses on research of microwave signal source based on phase-locked frequency-doubling technology, and it will be applied to chip-scale CPT atomic clock of Rb87. In recent years, with the development of science and technology, we have made further demands to the performance of atomic frequency, for example reducing size, weight, and its power consumption without sacrificing the stability of atomic frequency. Because of its low power consumption, small size, and the advantages of quick start, chip-scale CPT atomic clock has attracted the attention of many countries, and made the rapid development.In the design process of CPT atomic clock, we need a specific microwave frequency to stimulate atomic ground-state transition, so microwave signal source has an important role in the CPT atomic frequency standard. Moreover, the noise of atomic clock is mostly from microwave signal source, and it is the more prominent in the small atomic frequency standard system. Therefore, high-performance microwave signal source applied to chip-scale atomic clock must have the characteristics of high spectral purity, low phase noise and spurious waves less.This paper reviews the history of the development of atomic frequency standards and research status, and focuses on the development of Rb87 CPT atomic clocks and microwave signal source applied to chip-scale CPT atomic clock of Rb87. We have designed specifically signal source by phase-locked frequency-doubling technology, and elected oscillator of temperature compensated and controlled by voltage as a reference signal source, this will improve the frequency accuracy of microwave signal source, reduce phase noise and spurious waves. Based on this, we conducted analysis of phase-locked frequency-doubling technology, furthermore analyzing elements and methods of the low-noise, high-performance design. Through the choice of device, design of circuit board, simulation, modify, re-engineering and debugging, finally we have designed excellent the microwave signal source, and the center frequency is 3.417340GHz, range of power is from -25dBm to 12dBm, and the phase noise is -65dBC/Hz, -88dBC/Hz, -119dBC/Hz, and -140dBC/Hz, when the frequency is 1KHz, 10KHz, 100KHz and 1MHz. After analysis, the microwave signal source can be applied to chip-scale CPT atomic clock of Rb87, it has laid a solid foundation for realization of chip-scale CPT atomic clock.