全光纤结构超短脉冲超连续谱的产生及其特性研究

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

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。

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.