Ji Jingru, Wang Haotian, Ma Jie, Guo Jun, Zhang Jianing, Tang Dingyuan, Shen Deyuan
Opt Lett. 2022 Mar 15;47(6):1525-1528. doi: 10.1364/OL.450458.
Strong and narrow spectral feedback plays a key role in self-injection locking (SIL) single-frequency lasers, especially in the stabilization of single longitudinal mode (SLM) operation of a multi-mode laser. Here, we report on a narrow linewidth SIL fiber laser that adopts a fiber add-drop configuration composing of two tapered fibers and a high-Q MgF crystalline whispering-gallery-mode resonator. The feedback from the drop port could be controlled and optimized for stable SLM lasing of multi-mode fiber lasers. A stable single-frequency fiber laser with white frequency noise as low as ∼0.4 Hz/Hz, corresponding to an instantaneous linewidth of ∼1.26 Hz, is demonstrated. Compact, controllable, and all-fiber configuration in this work to achieve an ultra-narrow linewidth laser will attract interest in many applications.
强而窄的光谱反馈在自注入锁定（SIL）单频激光器中起着关键作用，特别是在多模激光器的单纵模（SLM）运转的稳定方面。在此，我们报道一种窄线宽SIL光纤激光器，它采用由两根锥形光纤和一个高Q值MgF2晶体回音壁模式谐振器组成的光纤分插配置。来自分插端口的反馈可被控制和优化，以实现多模光纤激光器的稳定单纵模激光振荡。实验展示了一种稳定的单频光纤激光器，其白频噪声低至约0.4 Hz/Hz，对应瞬时线宽约1.26 Hz。这项工作中实现超窄线宽激光器的紧凑、可控且全光纤配置将在许多应用中引起关注。
