高功率单频光纤放大器中温度分布对受激布里渊散射的影响

Influence of Temperature Distribution on Stimulated Brillouin Scattering in High Power Single-Frequency Fiber Amplifiers

从含有受激布里渊散射(SBS)的速率方程组出发,研究单频光纤放大器中,光纤内的温度分布对SBS的影响。计算表明,增大光纤内的温度梯度,可使得SBS的增益谱变宽,增益系数降低,进而抑制SBS;冷却信号光输出端附近的光纤,以增大光纤内的温度梯度,能有效抑制SBS;采用冷却光纤的方法来抑制SBS时,冷却光纤的位置和长度均存在最佳值,最佳值与抽运功率、温度梯度以及放大器中光纤总长度有关;采取最佳的冷却措施,能将抽运功率的阈值和放大器的输出功率提高2倍以上。

The influences of temperature distribution on stimulated Brillouin scattering（SBS） in high power single-frequency fiber amplifier are studied,based on the rate equations combining with SBS.The results indicate that temperature gradients along a fiber can broaden the SBS gain profile and thereby suppress SBS.The threshold of pump power and the output power of amplifier can be increased significantly by cooling fibers around the output port of amplifier actively.The length and location of fibers cooled to suppress SBS have the optima,which are influenced by pump power,temperature distribution and length of total fiber in amplifier.The threshold of pump power and output power of amplifier can be increased more than 2 times under the optimum condition.