Recent Advances Concerning the 87Sr Optical Lattice Clock at the National Time Service Center

We review recent experimental progress concerning the Sr-87 optical lattice clock at the National Time Service Center in China. Hertz-level spectroscopy of the Sr-87 clock transition for the optical lattice clock was performed, and closed-loop operation of the optical lattice clock was realized. A fractional frequency instability of 2.8 x 10(-17) was attained for an averaging time of 2000 s. The Allan deviation is found to be 1.6 x 10(-15)/tau(1/2) and is limited mainly by white-frequency-noise. The Lande g-factors of the (5s(2))S-1(0) and (5s5p)P-3(0) states in Sr-87 were measured experimentally; they are important for evaluating the clock's Zeeman shifts. We also present recent work on the miniaturization of the strontium optical lattice clock for space applications.