1Key Laboratory of Time and Frequency Primary Standards, National Time Service Center, Xi'an 710600 2School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049
Abstract：We present two cavity-stabilized lasers at 1555 nm, which are built to be the frequency source for a transportable photonic microwave generation system. The frequency instability reaches the thermal noise limit ($7\times10^{-16})$ of the 10-cm ultra-low expansion glass cavity at 1–10 s averaging time and the beat signal of the two lasers reveals a remarkable linewidth of 185 mHz.
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