A Compact Design of a Transportable Calcium Optical Frequency Standard

Since the instability and uncertainty of optical frequency standards have achieved the level of 10 −18 , and since the locking time of these frequency standards has become much longer, it is appropriate and necessary to build more practical optical frequency standards. Here we propose a compact design of a transportable Calcium optical frequency standard with the purpose of realizing a long time running optical clock. The design consists of an electronic cabinet and an optical cabinet. The total volume designed is 1.2 m 3 , with the electronic cabinet 0.8 m 3 and the optical cabinet 0.4 m 3 . It is designed to achieve a short term instability of $5\times 10^{-14}\ \tau^{-1/2}$ (1–1000s) and a mean time between failures (MTBF) of 8 hours. It may have the potential to be used as an optical timekeeping clock with the long term instability and MTBF optimized.