2μm波段混合复合谐振腔型单纵模光纤激光器

2-μm-Band Hybrid Compound-Resonating-Cavity Single-Longitudinal-Mode Fiber Laser

设计并演示了一种2μm波段高信噪比混合复合谐振腔型单纵模(SLM)掺铥光纤激光器(TDFL)。混合复合谐振腔由基于3个均匀光纤布拉格光栅(FBG)和2个光纤耦合器(OC)的非对称线形复合四腔和基于另外2个OC的双OC环形腔组成。基于游标原理,非对称线形复合四腔可以实现激光SLM选择。双OC环形腔作为窄带滤波器,进一步确保激光器长时间SLM稳定运行。采用放大的1567 nm激光泵浦掺铥光纤,当泵浦功率为2.80 W时,激光输出中心波长为2049.160 nm,输出功率为15.47 mW,光信噪比高达75.65 dB,200 min测量时间内波长和功率波动分别小于0.005 nm和0.85 dB,10 min测量时间内激光可以保持稳定的SLM运行,激光器的阈值泵浦功率和斜率效率分别为1.75 W和1.43%。提出的TDFL在自由空间光通信、激光雷达、光学传感等领域具有潜在的应用价值。

We propose a 2-μmband high optical signaltonoiseratio(OSNR)hybrid compoundresonatingcavity(CRC)singlelongitudinalmode(SLM)thuliumdoped fiber laser(TDFL).The hybrid CRC consists of an asymmetric linear compoundfourcavity(ALCFC)made of three uniform fiber Bragg gratings(FBGs)and two optical couplers(OCs),as well as a dualcouplerring(DCR)cavity made of two OCs.Based on the Vernier effect,the ALCFC can select the SLM from dense longitudinal modes,and the DCR is used as a narrowband filter to further stabilize the operation of SLM lasing over a long term.A 1567-nm laser diode amplified by a highpower erbiumdoped fiber amplifier is used as a pump source.Under a pump power of 2.80 W,a stable SLM laser output is achieved at a center wavelength of 2049.160 nm with an output power of 15.47 mW and an OSNR as high as 75.65 dB.The fluctuations of the wavelength and power are respectively lower than 0.005 nm and 0.85 dB within a measurement time of 200 min.The SLM operation becomes stable within 10 min.The pump threshold and slope efficiency are 1.75 W and 1.43%,respectively.The proposed TDFL has potential for applications in freespace optical communication,laser radar,and optical sensing.