A High Performance and Portable Optically Pumped Cesium Beam Frequency Standard

As optical frequency standard [1]-[4] and frequency comb developed with quite high precision(10
^-18
or 10
^-19
) and commercial H-maser developed with quite good short-term stability(10
^-15
), the only and core competitiveness of Cesium beam frequency standards(CBFS) are reliability and long-term stability today. We developed a high performance and portable optically pumped CBFS and the instability is 3×10
^-13
/√{τ} with the flicker floor expecting to be 3×10
^-15
. It has the best longterm performance of the optically pumped CBFS operated with an 852nm distributed feedback(DFB) laser ever measured with such a good short-term stability. Such a good result is attributed to the excellent control of the microwave power, C field and laser power. The portable CBFS can be used in many fields and is getting ripeness to substitute the existing magnetic selected products.