两种基于交叉相位调制的光脉冲压缩方案

Two kinds of optical pulse compression approaches based on cross phase modulation

基于交叉相位调制的时间透镜可实现精确的二次相位调制,但是它在光脉冲压缩领域的应用受到了抽运光脉冲的峰值功率过高的限制.对该峰值功率的表达式进行了推导,提出使用带有正色散的传输介质来实现输出段色散,从而降低了抽运光脉冲的峰值功率.并进一步指出,可以将基于交叉相位调制的时间透镜应用于4f系统,来实现光脉冲压缩,从而更有效地降低了抽运光脉冲的峰值功率.推导了该系统的抽运光脉冲的峰值功率和分辨率的表达式,并进行了光脉冲压缩的仿真分析.研究结果表明,在基于交叉相位调制的4f系统中,可以利用峰值功率较低的抽运光脉冲产生飞秒量级超短光脉冲;随着压缩系数的提高,输出光脉冲的脉冲宽度主要受到4f系统分辨率的限制,并对4f系统分辨率的提高进行了讨论.

Time lens based on cross phase modulation can realize accurate quadratic phase modulation. However, its application in optical pulse compression is restricted by the pump pulse with a high peak power. The formula of the peak power is deduced. It is proposed to use an output fiber with positive dispersion to lower the high peak power requirement for the pump pulse. It is also proposed to use a 4f system which consists of two time lenses to realize optical pulse compression, thereby more effectively lowering the peak power of the pump pulse. The formulas of the peak power and the resolution of the 4f system are deduced. The optical pulse compression is simulated and analysed. The research results demonstrate that in a 4f system based on cross phase modulation, femtosecond pulses can be generated by using pump pulses with small peak power; With compression factor increasing, the pulse width of the output pulse is restricted mainly by the solution of the 4f system. The method of improving the solution of the 4f system is discussed.