超辐射掺铒光纤脉冲放大器的时间特性分析

Time-dependent characteristics of pulsed Er-doped superfluorescent fiber amplifiers

为了分析掺铒光纤脉冲超辐射放大器的输出特性,通过对时变激光速率方程求解的方法,进行了理论分析和数值验证,获得了系统对不同调制频率的响应和输出特性。结果表明,在一定频率范围内,将产生高峰值超辐射脉冲序列。用0.1W抽运1m铒光纤放大,种子具有纳秒级调制周期且占空比为1/2时,输出脉冲峰值渐减,约200ns后渐趋稳定。通过调节种子信号的光谱特性、调制特性并选择合适的光纤参量,可以控制放大脉冲性质。这一结果为利用超辐射光纤光源产生高功率、光谱性质可调的脉冲提供了有效途径,在1.5μm大气窗口及远程应用中具有实际价值。

After solving time-dependent rate equations, the transient performance of superfluoreseent fiber amplifiers was studied and the system＇s output characteristics and response to different modulation frequency were obtained. As long as modulation rate is within a certain range,high-peak-power pulses would be generated. For lm Er-doped fiber pumped by 0. 1W and the seed modulated in nanosecond range with duty cycle of 50% ,the amplifier outputs pulses with declining peaks ,and stabilizes after about 200ns. Characteristics of the amplified signal could be controlled by monitoring the seed＇s pulse and spectral properties. The study suggests possible means to produce high power pulses with ampeified spowtaneous emission fiber source whose mean wavelength and spectral width are manipulable,and has practical value in long-distance application within 1.5μm atmospheric window