微结构光纤近红外色散波产生的研究

Study of near-infrared dispersion wave generation for microstructured fiber

采用有限元法对实验室自制的非线性微结构光纤进行理论分析,表明该光纤具有良好的非线性和色散波产生的相位匹配特性.为实现微结构光纤非线性的全光纤化,本实验采用中心波长为1032 nm的光纤飞秒激光器作为抽运源,获得了753—789 nm的近红外色散波.实验中发现色散波中心波长和带宽随着抽运功率的改变会产生明显变化,并且在不同光纤长度时,色散波的频移量不同,脉冲展宽及频谱也会有明显的变化.实验结果与理论分析一致.这些结果对实现微结构光纤非线性的全光纤化具有良好的借鉴作用,为生物医疗应用特别是非线性光学显微成像术的近红外光源研究打下基础.

Properties of nonlinear microstructured fiber fabricated in our laboratory are theoretically analyzed using the finite element method. This fiber has a high nonlinearity and phase matching for the dispersion wave generation. To achieve all-fiber nonlinearity in microstructured fiber, the dependence of dispersion wave on the pump power is investigated.When changing the pump power at 1032 nm with a femtosecond fiber laser, the near-infrared dispersion waves cover a region from 753 to 789 nm. The central wavelength and bandwidths alter obviously, and the fiber length has a remarkable impact on pulse broadening and frequency spectrum. Results coincide with the analyses. These results could be a reference for all-fiber nonlinearity of microstructured fiber, and lay a foundation for biological and medical applications, especially some researches on the near-infrared source for nonlinear light microscopy.