Lv Ruidong, Chen Tao, Huang Jin, Sun Zenghui, Hou Yuxing, Si Jinhai, Zhou Yuan, Du Yong, Hou Xun
Appl Opt. 2024 Mar 10;63(8):2004-2010. doi: 10.1364/AO.504935.
We demonstrate a single longitudinal mode distributed Bragg reflection (DBR) fiber laser by directly fabricating fiber Bragg gratings (FBGs) on an ytterbium-doped fiber (YDF) using a femtosecond laser. A simple optical self-injection feedback method was used to effectively compress the linewidth and reduce relative intensity noise (RIN) of a single longitudinal mode DBR fiber laser. Further, we investigated the effect of self-injection feedback cavity length and reflectivity on linewidth compression and determined that the linewidth tends to decrease with the increase of the external cavity photon lifetime. By a self-injection feedback, the laser linewidth was compressed from 31.8 kHz to 1.4 kHz. Meanwhile, the relaxation oscillation peak from -103.2 / at 1.51 MHz was suppressed to -122.3 / at 0.16 MHz. This low-noise narrow linewidth single longitudinal mode fiber laser is expected to be a promising candidate for applications such as active detection of neutral atmosphere and distributed fiber sensing.
我们通过使用飞秒激光在掺镱光纤（YDF）上直接制作光纤布拉格光栅（FBG），展示了一种单纵模分布布拉格反射（DBR）光纤激光器。采用一种简单的光学自注入反馈方法，有效压缩了单纵模DBR光纤激光器的线宽并降低了相对强度噪声（RIN）。此外，我们研究了自注入反馈腔长度和反射率对线宽压缩的影响，并确定线宽随外腔光子寿命的增加而趋于减小。通过自注入反馈，激光线宽从31.8 kHz压缩至1.4 kHz。同时，弛豫振荡峰从1.51 MHz时的-103.2 dB/Hz被抑制到0.16 MHz时的-122.3 dB/Hz。这种低噪声窄线宽单纵模光纤激光器有望成为诸如中性大气有源探测和分布式光纤传感等应用的有前景的候选者。
