Sun Yuxin, Zhao Qilai, Wang Changhe, Zeng Chun, Lin Wei, Yang Changsheng, Feng Zhouming, Zhang Qinyuan, Yang Zhongmin, Xu Shanhui
Opt Lett. 2022 Sep 1;47(17):4475-4478. doi: 10.1364/OL.468045.
An over-20-octaves-bandwidth ultralow-intensity-noise 1064-nm single-frequency fiber laser (SFFL) is demonstrated based on a comprehensive all-optical technique. With a joint action of booster optical amplifier (BOA) and reflective Yb-doped fiber amplifier (RYDFA), two-fold optical gain saturation effects, respectively occurring in the media of semiconductor and fiber, have been synthetically leveraged. Benefiting from the gain dynamics in complementary time scales, i.e., nanosecond-order carrier lifetime in BOA and millisecond-order upper-level lifetime in RYDFA, the relative intensity noise (RIN) is reduced to -150 dB/Hz from 0.2 kHz to 350 MHz, which exceeds 20-octaves bandwidth. Remarkably, a maximum suppressing ratio of >54 dB is obtained, and the RIN in the range of 0.09-10 GHz reaches -161 dB/Hz which is only 2.3 dB above the shot-noise limit. This broad-bandwidth ultralow-intensity-noise SFFL can serve as an important building block for squeezed light generation, space laser communication, space gravitational wave detection, etc.
基于一种综合全光技术，展示了一种具有超过20倍频程带宽的超低强度噪声1064纳米单频光纤激光器（SFFL）。在增益放大光放大器（BOA）和反射式掺镱光纤放大器（RYDFA）的共同作用下，分别在半导体和光纤介质中出现的两种光增益饱和效应被综合利用。受益于互补时间尺度上的增益动态特性，即BOA中纳秒级的载流子寿命和RYDFA中毫秒级的高能级寿命，相对强度噪声（RIN）从0.2千赫兹到350兆赫兹降低到-150分贝/赫兹，超过了20倍频程带宽。值得注意的是，获得了大于54分贝的最大抑制比，并且在0.09 - 10吉赫兹范围内的RIN达到-161分贝/赫兹，仅比散粒噪声极限高2.3分贝。这种宽带宽超低强度噪声SFFL可作为产生压缩光、空间激光通信、空间引力波探测等的重要组件。
