基于光纤环形镜的全光脉冲整形器

An All-Optical Pulse Shaper Based on Nonlinear Optical Loop Mirror

提出了一种基于光纤环形镜的全光脉冲整形器。该全光脉冲整形器利用波分复用器将控制光脉冲引入光纤环形镜中,控制光脉冲由于交叉相位调制在信号光上产生了非线性附加相移。信号光在耦合器中发生干涉,经过整形的信号光脉冲从脉冲整形器的出射端出射,信号脉冲的波形由非线性附加相移的波形决定。实验中,利用对控制脉冲光谱整形和啁啾展宽的方法来对控制脉冲进行时间脉冲的整形,该全光脉冲整形器实现了对单纵模激光的脉冲整形,同时实现了飞秒脉冲和单纵模整形脉冲的精确同步。在理论上数值计算了该全光脉冲整形器的输出特性,理论计算结果和实验结果相一致,并为“快点火”实验提供了一条可行的技术途径。

A novel all-optical pulse shaper based on nonlinear optical loop mirror is proposed in this letter, Control pulse is coupled into this pulse shaper by wavelength division multiplexer. Nonlinear phase shift of signal laser is induced by control pulse because of cross phase modulation. Signal laser interferes in fiber coupler, then shaped signal pulse transmits from output port of this pulse shaper. Signal pulse＇s waveform is determined by the profile of the nonlinear phase shift. In this experiment, control pulse is temporary pulse shaped by spectrum shaping and chirped stretching, and single-longitudinal-mode laser is successfully pulse shaped in this all-optical pulse shaper. what＇s more, precise synchronization between femtosecond pulse and single longitudinal-mode shaped pulse is achieved. The output property of this pulse shaper is numerically analyzed in theory, and the results are same as experimental ones. This all-optical pulse shaper provides a potential technical method for “fast ignition” experiment.