基于光纤噪声抑制系统的1.5μm超稳激光系统比对

Comparison of 1.5μm Ultra-Stable Laser Systems Based on Fiber Noise Suppression System

搭建了一套光纤相位噪声抑制系统。通过环外自拍频,得到噪声本底的秒级频率稳定度为6.8×10^(-18),2000s平均时间后达到2.3×10^(-19)。利用该系统可实现窄线宽激光频率在1.6km实际光纤链路中的传输,传输后环外自拍频信号的秒级频率稳定度可达1.2×10^(-17)。基于连接两个实验室的808m实际光纤链路,将此系统应用于1.5μm超稳激光的比对,通过拍频测量得到激光线宽为(0.54±0.15)Hz,秒级频率稳定度为1.2×10^(-15)。

A fiber phase noise suppression system is built. By out-of-loop self-beat frequency, the noise floor of 6.8 × 10^-18 is obtained in the average time of 1 s, and it falls down to 2.3 × 10^-19 after the average time of 2000 s. The laser frequency with narrow linewidth is transferred in a 1.6 km fiber link when we use the proposed system, and the frequency stability of out-of-loop self-beat frequency signal is 1.2 × 10^-17 in the average time of 1 s. Based on the 808 m fiber link which connects the two laboratories, the laser linewidth of （0.54± 0.15） Hz and the frequency stability of 1.2 × 10 ^-15 in average time of 1 s can be obtained in beat frequency measurement when we apply the proposed system to the comparison of 1.5 μm ultra-stable laser systems.