基于MOPA结构的1550 nm单频脉冲光纤激光器

1055 nm single-frequency pulsed fiber laser based on MOPA structure

人眼安全的1550 nm全光纤单频脉冲激光器具有广泛且诱人的应用前景。本文所研制的激光器采用全光纤主振荡功率放大(MOPA)结构和腔外声光调制的方法,一级预放大级采用1.5 m单模保偏掺铒光纤,输出功率21.45 mW;二级预放大级采用1.5 m双包层保偏铒镱共掺光纤,输出功率253.6 mW;功率放大级采用1 m双包层保偏大芯径铒镱共掺光纤,泵浦功率15.9 W时,最终实现了输出功率2.6 W、脉宽260 ns、重复频率10 kHz的单频脉冲激光输出。通过对各级增益光纤和无源光纤的长度优化,成功抑制了放大自发辐射(ASE)和受激布里渊散射(SBS),消除了放大过程中噪声的影响,得到了峰值功率1 KW的稳定单频脉冲特性。

The eye-safe 1550 nm all-fiber single-frequency pulsed laser has broad and attractive application prospects.The laser developed in this paper adopts all-fiber main oscillation power amplification(MOPA)structure and out-of-cavity acousto-optic modulation method.The first-stage preamplifier stage adopts 1.5 m single-mode polarization-maintaining erbium-doped fiber with the output power of 21.45 mW;the second-stage adopts 1.5 m double-clad polarization-preserving co-doped fiber with the output power of 253.6 mW;the power amplifier stage adopts 1m double-clad polarization-maintaining large-core-diameter co-doped fiber,and when the pump power is 15.9 W,the single-frequency pulsed laser output with power 2.6 W,pulse width 260 ns,and repetition rate 10 kHz,is finally realized.By optimizing the length of the gain fiber and the passive fiber at each level,the amplified spontaneous emission(ASE)and Stimulated Brillouin Scattering(SBS)are successfully suppressed,the influence of noise during the amplification process is eliminated,and the single frequency pulse characteristics with peak power up to 1 kW is obtained.