全光纤保偏放大器产生196W近红外超连续谱

196 W Near Infrared Supercontinuum Generation in an All-Fiber Polarization-Maintaining Power Amplifier

采用全光纤结构保偏光纤放大器生成了高偏振度超连续谱。种子源使用一个中心波长为1064nm，重复频率、脉冲宽度均可调的保偏脉冲光纤激光器，将种子激光器设置在重复频率5MHz，脉宽150ps，输出功率80mW。种子光经过一个主振荡功率放大（MOPA）结构的保偏光纤放大器进行功率放大，经过两级预放大器和一级主放大器进行功率放大，并在主放大器中使光谱展宽，产生了高偏振度的超连续谱激光。主放大器采用纤芯／内包层直径为25μm／400μm的保偏双包层掺镱光纤，其长度为11m，在976nm处的吸收系数为2．2dB／m。当主放大器的抽运光功率为355W时，得到的超连续谱激光输出平均功率为196W，斜率效率为55％，输出光谱范围为0．85～1．86μm。

Polarization-maintaining （PM） supercontinuum is generated in an all-PM-fiber amplifier. A tunable fiber pulse laser with the central wavelength 1064 nm is used as the seed of the master-oscillation power-amplifier （MOPA）, and the output power of the seed is 80 mW while the repetition frequency and the pulse width are tuned to 5 MHz and 150 ps, respectively. The pulse is amplified through two PM-pre-amplifiers and then coupled into 11 m long double-cladding PM ytterbium-doped fiber （YDF）, which has core/inner-cladding dimensions of 25 μm/400 μm and the absorption coefficient of the fiber is 2.2 dB/m at 976 rim. With the pumped power of 365 W, the average power of the supercontinuum generated in the amplifier is measured as 196 W, with the slope efficiency of 55%, while the spectra extend from 0.85 μm to 1.86 μm.