光纤放大器中有限增益带宽对自相似脉冲放大演化的数值研究

通过求解包含超高斯增益系数滤波项的分布增益非线性薛定谔方程,模拟研究了短脉冲在有限增益带宽指数增益光纤放大器中的自相似演化行为及其差异。结果表明脉冲在不同指数增益分布放大器中传输时都会受到增益带宽的限制。相同输入脉冲在相同长度、相同总增益的指数上升、下降和双向分布放大器中放大时,在双向分布放大器中输出能量最高,输出脉冲线性啁啾特性最好,指数下降放大器输出能量最低,输出脉冲线性啁啾特性最差,指数上升放大器居两者之间。另外,总增益相同时,无论是指数上升、下降和双向分布放大器,初始增益系数较小,输出脉冲能量较高,脉冲线性啁啾特性较好。

Influences of Finite Gain Bandwidth on Evolution of Self-Similar Pulse Propagation in Fiber Amplifiers

The evolutions of the pulse propagation in gain distributed fiber amplifiers with a finite gain bandwidth are investigated with the simulation of the nonlinear Schrdinger equation. The results show that the parabolic pulse propagations in different gain amplifiers are restricted by the finite gain bandwidth. With the same input pulse and amplifier length and overall gain, the largest energy and best linear chirp output pulse can be obtained from the bidirectional gain distributed fiber amplifier. The smallest and worst linear chirp pulse output can be obtained from decreasing gain distributed fiber amplifier, while pulse obtained from decreasing gain distributed fiber amplifier is between them. Moreover, by choosing smaller initial gain coefficient, the whole gain limited by the gain bandwidth may be larger, linear chirp is better with the same overall gain.