Development of the strontium optical lattice clock at national time service center

A closed-loop operation optical lattice clock of
⁸⁷
Sr has been realized built in National Time Service Center of China. The linewidth of spin-polarized clock transition spectrum is 3.9 Hz with a interrogating time of 300 ms. The instability is measured to be about 5×10
^-15
/ τ
^1/2
from the fit function of the in-loop error signal data, which affected mainly by the white noise. The fractional frequency difference averages down to 6×10
^-17
at an average time of 3000 s.