用于空间外差光谱仪光谱定标的窄线宽可调谐光纤激光器

Narrow-linewidth tunable fiber laser for spectral calibration of spatial heterodyne spectrometer

针对星载CO_2遥感探测空间外差光谱仪2.04μm通道光谱定标的应用需求,研制了一台2.04μm波段窄线宽波长可调谐的高稳定性铥钬共掺光纤激光器(THDFL)。利用线型复合谐振腔的维纳效应扩大有效纵模间隔,有效抑制了多模激光振荡,输出激光线宽达7.5 MHz;通过对振动隔离和温度补偿封装的FBG施以轴向拉伸应力,该THDFL可在2040~2042.5 nm范围内调谐,且输出波长不确定度小于5×10^(-3)nm;使用研制的1565 nm光纤激光泵浦源,THDFL输出功率达192 mW;利用该可调谐THDFL提供的输出激光,溯源于波长标准后实现了空间外差光谱仪2.04μm通道的光谱定标,且定标精度优于设定的指标要求。

Aiming at the application requirements of spectral calibration at 2.04μm channel of the spatial heterodyne spectrometer used for spaceborne CO2 remote sensing detection, a narrow-linewidth, tunable and highly-stable Tm/Ho co-doped fiber laser （THDFL） is developed. The effective longitudinal mode spacing is expanded by using Wiener effect of the linear compound resonant cavity. The multi-mode laser oscillation is effectively suppressed, and the output laser linewidth reaches 7.5 MHz. By axially stretching the FBG packaged with temperature compensation and vibration isolation techniques, the THDFL can be tuned from 2040 nm to 2042.5 nm, and the output wavelength uncertainty is less than 5×10-3nm. The output power of THDFL reaches 192 mW with the developed 1565 nm fiber laser pumping source. Using the output laser provided by the tunable THDFL, spectral calibration of the spatial heterodyne spectrometer at 2.04 μm channel is realized after being originated to a wavelength standard, and the calibration accuracy is better than the set index requirements.