中文摘要：

研究了L-波段超荧光在光纤中的产生机理，设计了一种带光纤圈反射器的双级双程前向输出L-波段光源结构，通过对两级采用掺铒浓度不同的光纤并优化其长度及两级泵浦光功率，实验中获得了功率高达19．86mW（12．98dBm）、中心波长为1577．421nm的L-波段（1555—1620nm）超荧光光源。实现了低浓度掺铒光纤起诱导光及改善光谱的作用，高浓度光纤为主要发光源，采用光纤圈反射器提高了泵浦光的利用效率、光源的平坦度及稳定性。同时分析了结构中各个参量对光源各方面性能的影响，对光源的设计具有指导意义。

英文摘要：

The primary principle of L-band superfluorescent fiber source was presented. A novel dual-stage double-pass forward pumping configuration with the fiber loop reflector was designed and achieved. Through experiment by optimization the parameter such as fiber length and pump power at two stages, the output power of L-band was high up to 19.86mW（ 12. 98dBm） ,and mean wavelength was 1577. 421nm. The ASE of first stage was used as seed signal, the second was main source of L-band, the efficiency of pumping and flatness was enhanced by using the first stage and fiber loop reflector. Meanwhile, the effect about source with different parameters was analyzed, it can provide help for design of the source.