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 m3, with the electronic cabinet 0.8 m3and the optical cabinet 0.4 m3. 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.