1.9~4.3 μm全光纤中红外超连续谱光源

All-Fiber Mid-Infrared Supercontinuum Source from 1.9 μm to 4.3 μm

利用在中红外波段具有低损耗的ZBLAN（ZrFt—BaF2-LaF3-A1Fs—NaF）氟化物单模光纤搭建了全光纤结构的超连续谱光源，将超连续谱在长波方向扩展到中红外波段。系统以波长为1550nm的纳秒脉冲半导体激光器作为种子源，采用主振荡功率放大结构实现了级联超连续谱产生。在前级超连续谱产生中将光谱预展宽到2．6／lm，再经掺铥双包层光纤放大器放大位于铥离子增益带宽内的光谱分量，最后抽运10m长的ZBLAN单模光纤，在光纤色散和非线性效应的作用下，获得了光谱覆盖1．9～4．3／am范围的中红外超连续谱输出，平均功率为185mw。

All-fiber mid-infrared supercontinuum source is obtained using ZBLAN （ZrF4-BaF2-LaF3-AlF3-NaF） single-mode fiber, which has low transmission loss in this wavelength region. The supercontinuum is extended to mid-infrared wavelength. This scheme is based on multi-stage supercontinum generation in master oscillator power amplifier with nanosecond pulsed semiconductor seed laser operating at 1550 nm. The spectrum of seed laser is extended to 2.6 μm in Tm/Ho co-doped fiber, and the wavelength components lying in the gain band of Tm doped fiber are amplified in Tm doped double-clad fiber amplifier and then pump 10-m ZBLAN single-mode fiber. Spectral broadening from 1.9 μm to 4.3 μm with average output power of 185 mW is achieved resulting from the interaction between dispersion and nonlinear effects.