掺铥光纤激光器波长可调谐输出特性

利用1 550 nm光纤激光器搭建了一个同带泵浦环形腔掺铥光纤激光器，并对其光谱输出特性进行了研究。在1 550 nm激光泵浦下，1.6 m掺铥光纤自发辐射谱覆盖1 800~1 900 nm范围，3 dB带宽大于60 nm；通过在腔内插入隔离器，获得了线宽小于0.2 nm的激光输出，中心波长在1900 nm附近；进一步在腔内加入FP腔，获得了可调谐的窄线宽输出，光谱调谐范围达60 nm，覆盖从1 840~1 900 nm的光谱范围，激光线宽仅为0.07 nm。另外，在腔内使用通信波段用FP腔，同样获得了较宽调谐范围的窄线宽输出。输出光谱分为1 820~1 850 nm和1 865~1 915 nm两个区域，调谐范围共达80 nm。结合使用2 000 nm FP腔的可调谐光谱范围，该激光器在1 820~1 915 nm的范围都可以获得激光输出，与掺铥光线的自发辐射谱基本相符。

Output characteristics of tunable Tm-doped fiber lasers

A ring cavity Tm-doped fiber laser system was built based on a 1 550 nm fiber laser. And, its spectral chacteristics were investigated. With 1 550 nm pump, the spontaneous emission of the 1.6 m long Tm-doped fiber covered a spectral range from 1 800-1900 nm with a 3 dB bandwidth bigger than 60 nm. Inserting an isolator into the ring cavity, narrow linewidth output was obtained with a 3 dB linewidth smaller than 0.2 nm centering at around 1 900 nm. Further adding a tunable FP filter, tunable, narrow linewidth laser output was attained. The laser spectrum was tunable from 1 840-1 900 nm with a broad tunable range reaching 60 nm while maintaining a 3 dB linewidth of only 0.07 nm. In addition, a telecommunication FP filter at the 1 550 nm waveband was also exploited in this ring cavity laser system for wavelength tuning. And, a narrow linewidth, broadband tunable laser output in two seperated spectral ranges was also recorded. Together with the 2 000 nm FP laser system, this laser demonstrates a wide tunable range from 1 820-1 915 nm which is consistent with the spontaneous emission spectrum of the Tm-doped fiber.