研究了长脉冲抽运光子晶体光纤(PCF)正常色散区超连续谱的产生。依据透镜耦合的基本条件设计了激光器与入射光纤之间的耦合系统,该系统的耦合效率可以达到60%;实现了模场不匹配的普通光纤与光子晶体光纤的低损耗熔接,实验测得的熔接损耗为3.8 dB,低于理论计算的熔接损耗5 dB。随着抽运功率的增加,产生了平均功率为1.2 W,10 dB的带宽为710-1700 nm的超连续谱。实验结果表明,长脉冲抽运光子晶体光纤的正常色散区,受激拉曼散射在光谱加宽的最初阶段发挥了重要作用,而高阶孤子分解和交叉相位调制促使超连续谱趋于更宽、更平坦。

Supercontinuum generation in the normal-dispersion regime of photonic crystal fibers (PCFs) with long pulse pumping has been experimentally investigated. The coupling system between laser and fibers is designed based on essential conditions of lens coupling,by which the coupling efficiency can reach 60%. Low splicing loss is realized. Splicing loss is mainly caused by modal field mismatch of conventional fiber and PCFs. Theoretic value is 5 dB,while the experimental value is 3.8 dB. Supercontinuum generation is experimentally studied as pump power increases,and supercontinuum spanning from 710 nm to 1700 nm of 10 dB bandwidth with average power up to 1.2 W is generated. The experimental results show that stimulated Raman scattering (SRS) plays an important role in the onset of spectral broadening,then fission of higher-order solitons and cross-phase modulation make supercontinuum broader and flatter.