渐变折射率多模光纤产生可见光超连续谱研究进展

Research Advances of Visible Supercontinuum Generation in Graded-Index Multimode Fibers

渐变折射率多模光纤中存在几何参量不稳定性等时空非线性效应,在一定条件下会使传输激光的光谱逐渐展宽,最终演化为超连续谱。本文介绍了几何参量不稳定性的概念、物理内涵以及利用渐变折射率多模光纤获得可见光超连续谱的研究现状,分析了光纤参数、脉冲参数对输出光谱的影响,提出实现全光纤结构以及采用短波长激光作为泵浦源是今后研究的重点方向。利用几何参量不稳定性产生可见光超连续谱有望突破传统光子晶体光纤产生可见光超连续谱方案因纤芯过小造成的功率限制。

Typically,gradedindex multimode fibers feature certain spatiotemporal nonlinear effects such as geometric parametric instability(GPI),which gradually expands the spectrum of transmitted laser light under certain conditions and eventually evolves into a supercontinuum.This paper introduces the concept of GPI and its physical connotations;moreover,the status of research on GPIinduced visible supercontinuum generation in gradedindex multimode fibers is reviewed,and an analysis on the influence of fiber and pulse parameters on the output spectrum is presented.In addition to this,realizing an allfiber structure and using short wavelength lasers as pump sources constitute key future research directions.Overall,the GPIinduced generation of the visible supercontinuum is expected to break through the power limitation of the supercontinuum generated by small core traditional photonic crystal fibers.