提出了一种结构新颖的L波段环形腔掺铒光纤激光器。用掺铒光纤作为增益介质，采用980 nm激光器作为前向抽运源，利用起偏器和偏振控制器获得L波段激光，利用光环形器将后向的放大自发辐射再引入铒光纤的前端，重复利用。当抽运功率为103 mW时得到了阈值功率约为23.87 mW，输出功率达6.34 mW的激光输出，斜率效率约为8.05%,与没有重复利用后向放大自发辐射谱的掺铒光纤激光器做比较，该结构对L波段掺铒光纤激光器的性能有明显的提升作用。对于长度不合适的铒纤，在没有重复利用后向放大自发辐射谱时没有获得激光输出；而在利用后向放大自发辐射后，在阈值功率约为88 mW时得到了激光输出，从而很好地证明了上述结论。

A novel structure L-band erbium-doped fiber ring laser is demonstrated. The ring cavity is constituted by erbium-doped fiber (EDF) as the gain medium, a 980 nm laser diode as the co-pumping source, a polarizer and a polarization controller as the L-band wavelength selective device. To be recycled, the backward amplified spontaneous emission (ASE) was routed to the input of EDF by an optical circulator. The lasing threshold is approximately 23.87 mW, the output laser power reaches 6.34 mW and the slope efficiency comes up to about 8.05% when pumping power is set to 103 mW. Compared with the laser without utilizing backward ASE, it is apparent that the performance of L-band fiber ring laser has been much improved. When inapposite length EDF was used, no laser output was obtained without utilizing backward ASE; whereas laser with the threshold power of about 88 mW has been achieved with backward ASE compensation. Thus the above conclusion is well proved.