基于光子晶体光纤和拉锥式单模光纤的超连续光谱产生的实验研究

本文使用重复频率为250 MHz、脉冲宽度为135 fs、最大功率为2.2 W的锁模掺镱光纤激光作为种子源,利用光子晶体光纤和自制的拉锥式单模光纤两种高非线性光纤研究了超连续光谱的产生特性,通过对比两种光纤的结构、色散等特性,分析了拉曼孤子、色散波及其他非线性效应对产生的超连续谱形状的影响,并均得到了大于一个倍频程的超连续光谱,特别是拉锥式单模光纤产生的超连续光谱,耦合效率达到60%,这为众多研究领域,尤其是光学频率梳的建立提供了实用的超连续光源.

Supercontinuum generation in photonic crystal fiber and tapered single-mode fiber

Supercontinuum generation has received extensive attention because of the innovation of high nonlinear fiber, which makes the supercontinuum system more simple, compact, and efficient. Nonlinear effects are enhanced greatly during the strong interaction between the light and matter in high nonlinear fiber, and the spectrum will be broadened effectively. In this paper, we demonstrate the supercontinuum generation in a photonic crystal fiber and a conventional tapered single-mode fiber pumped by the mode-locked Yb fiber laser. Through the experimental comparison of the supercontinuum spectrum between two kinds of the high nonlinear fibers, the spectral flatness, Raman perturbation, and dispersion wave radiation are discussed for studying the characteristics of supercontinuum generation. Finally, the octave supercontinuum-based both kinds of high nonlinear fibers could be achieved. In particular, the employment of tapered single-mode fiber is proven to be an appropriate candidate for supercontinuum generation and further application.
Keywords： supercontinuum generation highly nonlinear fiber nonlinear optics femtosecond laser