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 5×10
^-14
τ
^-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.