增益锁定掺铒光纤环形激光放大器的低噪声特性

Low noise characterization of gain clamped erbium doped fiber ring lasing amplifiers

为了得到噪声性能优良的增益锁定掺铒光纤放大器，提出利用掺铒光纤放大器噪声指数曲线在浅饱和区有一凹陷的特性以及强激光功率对放大的自发辐射的抑制作用，可以改善增益锁定放大器的噪声特性，并在以反馈环路实现增益锁定的掺铒光纤放大器光路结构上实验研究了不同反馈深度对放大器的噪声特性的影响，结果表明在正向泵浦放大光路中引入同向选频激射，通过适当选择反馈深度即放大器的工作点，可以在获得足够宽的输入信号动态范围的同时获得比反馈锁定前更低的噪声指数。

In order to achieve the best performance of the gain clamped erbium doped fiber amplifier (EDFA), it is proposed that, by using of the phenomenon that the noise figure of EDFA shows a dip around the shallow saturation region and the effect that high laser power suppresses ASE power strongly, the noise characterization of the gain clamped ring lasing amplifier can be improved. Based on an optical configuration of EDFA with a ring feedback loop, the noise characterization of gain clamped EDFA was investigated experimentally. The results show that wide enough gain clamped dynamic region and low noise figure are achieved simultaneously if the operation point of the amplifier, i.e., the degree of feedback, is chosen properly when the pump and laser lights travel in the same direction as the signal.