一种新型窄线宽掺铒光纤激光器

摘要

为了实现稳定的窄线宽激光输出，设计了一种基于有源光纤环形滤波器的窄线宽掺铒光纤激光器，对其系统原理和实验分析进行了讨论。在环形腔中熔接一支分光比为50∶50的2×2熔融拉锥型耦合器，并且通过在该耦合器另外两端熔接一段长2 m 的有源光纤，构成有源光纤环形滤波器，实现压窄线宽的目的。实验结果表明，在熔接环形滤波器后，输出激光边模得到明显抑制；在0～400 MHz 频谱范围内，激光工作在单纵模运转状态；输出激光的3 dB线宽为3.4 kHz。%In order to achieve stable narrow line-width laser output,a narrow line-width erbium-doped fiber laser based on active fiber ring filter is designed,and its system theory and experimental analysis are discussed.The active fiber ring filter consists of a 50∶50 2 ×2 fused taper coupler and a 2 m erbium-doped fiber,and is capable of filtering out redundant longitudinal modes within the comb spectrum property of the system,so as to achieve the goal of narrowing the line-width.The experimental results show that,after incorporating the ring filter through fusion splicing,the side modes of the laser output are significantly suppressed.Specifically in the 0 ~400 MHz range,the laser works in a sin-gle longitudinal mode operation state,and the 3 dB line width of laser output is 3.4 kHz.