Long‑term stable 850‑Hz linewidth single‑longitudinal‑mode ring cavity fber laser using polarization‑maintaining fber

A long-term stable single-longitudinal-mode (SLM) all polarization-maintaining (PM) compound-ring cavity fber laser is reported. The results show that the PM fber’s strong ability to resist the environment disturbance allows fnely designing the length of each secondary cavity in real time according to the main cavity under the laboratory environment, and then the efective longitudinal mode spacing can be sufciently increased by accurately using the Vernier efect, so that the mode-hopping can be efectively suppressed. Furthermore, the temperature compensation is used for asynchronously fneadjusting each cavity length to follow the Vernier efect requirement more strictly. The mode-hopping-free SLM operation time of the packaged laser reaches 11 h. As far as we know, this is the longest SLM free running time of ring cavity fber laser to date. The optical signal to noise ratio of the laser reaches 77 dB and the linewidth is less than 850 Hz with up to 50 mW maximum output power

本文报道了一款长期稳定的单纵模（Single-Longitudinal-Mode, SLM）全保偏（Polarization-Maintaining, PM）复合环形腔光纤激光器。研究结果表明，保偏光纤具备优异的抗环境扰动能力，可在实验室环境下依据主腔实时精细化设计各副腔的长度；随后通过精准利用游标效应（Vernier Effect）可有效增大有效纵模间距，进而实现跳模的有效抑制。此外，本研究采用温度补偿方案对各腔长进行异步微调，以更严格地匹配游标效应的需求。封装后的激光器无跳模单纵模运行时长可达11小时。据我们所知，这是目前环形腔光纤激光器所实现的最长无跳模单纵模自由运行时长。该激光器的光信噪比（Optical Signal to Noise Ratio）可达77 dB，线宽小于850 Hz，最大输出功率可达50 mW。