全光纤结构超短脉冲超连续谱的产生及其特性研究

超连续光谱以其光谱范围宽、平坦度好、空间相干度高和可实现的较高功率,被广泛应用于相干成像技术、光谱分析、干涉测量等诸多领域.理论上超连续光谱可由超短脉冲通过高非线性介质来实现,期间伴随着自相位调制(SPM)、受激拉曼散射(SRS)、四波混频效应(FWM).随着光纤技术的发展,利用峰值功率高、光光转换效率高、体积小、结构紧凑的掺Yb超短脉冲光纤激光器作为泵浦源,高非线性的光子晶体光纤作为非线性介质来产生超连续光谱.采用主振荡功率放大结构(MOPA),自行搭建了全光纤锁模脉冲放大器,并通过熔接的方式将其耦合进入长为10 m、零色散点为1 040 nm的光子晶体光纤,在对熔接过程中放电时间、放电间隔、熔接损耗等参数进行优化后,获得了8.14 W的超连续光谱.

All- fiber ultra- short super- continuum generation and characters

Super-continuum (SC) is widely used in coherent photography technology, optical spectroscopy analysis, interferometry, etc because of its flat and broad spectrum, high spatial coherence and high power. Super-continuum generation could be realized on theory by ultra-short pulse laser getting through the high nonlinear medium, accompany with self-phase modulation (SPM), stimulated Raman scattering (SRS), four-wave mixing (FWM). With the development of fiber technology, Yb-doped ultra-short pulse fiber laser, which has high peak power, high optic-to-optic efficiency, compact structure and small volume was elected as the pump source, and high nonlinear photonic crystal fiber (PCF) as the nonlinear medium for SC. In this paper, a self-made amplified mode-locked pulse was coupled into a 10m PCF, with 1 040 nm zero dispersion point, to generate 8.13W super-continuum by fusing method, during which the key parameters like discharge time, discharge interval, splice loss are seriously optimized to keep the fusing quality well.