报道了一个全光纤的高效率超连续谱产生系统,系统采用增加一段匹配光纤的办法解决增益光纤和光子晶体光纤直接熔接损耗较大的问题,并且对匹配光纤和光子晶体光纤熔接对准过程进行实时监控,使熔接损耗降到最低,从而实现了较高的全系统转换效率(76%)和较好的光束质量。实验研究了超连续光谱展宽的过程,结果显示:超连续谱展宽的初始阶段,拉曼效应和自相位调制效应起主要作用,光谱呈现长波方向展宽较多的非对称性,并出现明显的拉曼斯托克斯峰;光谱继续展宽时,满足相位匹配条件的四波混频开始起作用,拉曼效应产生的加宽光谱成分作为四波混频参量过程的泵浦,使光谱开始向长波和短波两个方向扩展。

An all-fiber supercontinuum generation system has been demonstrated.In the system,a short matching fiber was used to reduce the loss in the connection of the gain fibers and the photonic crystal fiber,and real-time measurement was carried out in the splicing stage to minimize the loss.Such techniques ensure a whole system conversion efficiency of 76% and a good beam quality.The broadening process was analyzed experimentally and interpreted as follows.More broadened spectrum lies in the long wavelength region rather than in the short wavelength one,which indicates that Raman effect and self-phase-modulation dominate the initial broadening process.Meanwhile,Raman-Stocks peaks were obvious.As the broadening developing,the phase matched parametric four-wave mixing begins to occur,and Raman-effect-generated frequencies serve as parametric pumps,which extended the spectrum to both long and short wavelength ends.