掺铥双包层光纤激光器研究

掺铥光纤激光器所发射的2mm波段激光处于水分子吸收峰且对人眼安全,并且被认为是3～5mm光参量振荡的有效抽运源,因此具有巨大应用前景。围绕进口和国产掺铥双包层光纤展开了一系列研究,实现了光纤激光器的连续运转、脉冲运转、可调谐输出等。对进口光纤的光谱特性进行了较全面的研究,获得最大连续输出功率6W、斜率效率50%;采用国产掺铥双包层光纤,获得最大连续输出功率5.1 W、斜率效率41.9%;采用后向Littrow结构、以闪耀光栅作为选频元件,获得了2mm附近最大范围可达105nm的可调谐激光输出,且各调谐激光线宽均在2.2nm左右。采用声光调制器(AOM)作为Q开关,在调制频率为1kHz时,获得最高峰值功率4.2kW、最大脉冲能量840mJ、脉宽200ns的脉冲输出;在3kHz时获得了最短180ns的脉冲输出。对双端抽运方式也进行了研究。分析了腔镜透射率和激光介质长度对激光输出功率的影响,讨论了激光光谱的红移现象。

Studies on Tm-Doped Double-Clad Fiber Lasers

Tm-doped fiber lasers have a huge applied prospect because of their emitting wavelength about 2 μm in the absorption of water molecules,eye safety and being considered to be effective pump sources for 3~5 μm optical parametric oscillator.This paper launches a series of studies on continuous wave laser,pulsed laser and tunable laser with imported and domestic Tm-doped double-clad fibers.Spectral characteristics of imported fiber are studied,with the maximum output power of 6 W and the slope efficiency of 50% for continuous-wave(CW) operation.For domestic fiber,the maximum output power is 5.1 W and the slope efficiency is 41.9%.A back-Littrow configuration is adopted with a blazed grating as a frequency selecting component.The maximum tunable range reaches 105 nm,and the linewidth of each laser spectrum is about 2.2 nm in the tunable range.A Q-switched fiber laser with an acousto-optic modulator(AOM) is also reported.The laser generates pulses of 200 ns duration with 840 μJ pulse energy,corresponding to the peak power of 4.2 kW when the repetition rate is 1 kHz.The shortest duration of 180 ns is obtained with the repetition rate being 3 kHz.Laser diode(LD) double-end pumped Tm-doped fiber laser is also studied.The effect of fiber length and transmission of output mirror on output power is analyzed.A red shift in the wavelength of the output with the increase of the pump power is also discussed.