Zheng Aihu, Sun Qibing, Wang Leiran, Liu Mulong, Zeng Chao, Wang Guoxi, Zhang Lingxuan, Fan Weichen, Zhao Wei, Zhang Wenfu
Appl Opt. 2020 Feb 1;59(4):1187-1192. doi: 10.1364/AO.379232.
We investigate the influence of third-order dispersion of dispersive elements, three-photon absorption and free-carrier effects on mid-infrared time magnification via four-wave mixing (FWM) in ${{\rm Si}{0.8}}{{\rm Ge}{0.2}}$SiGe waveguides. It is found that the magnified waveform is seriously distorted by these factors, and conversion efficiency is decreased, mainly because of nonlinear absorption. A time lens based on FWM in ${{\rm Si}{0.8}}{{\rm Ge}{0.2}}$SiGe waveguides is proposed for time magnification of mid-infrared ultrashort pulses, in which the low-distortion, high-magnification in the time domain could be obtained by optimizing system parameters. These results make it possible to analyze the transient dynamic process through oscilloscopes and detectors with gigahertz bandwidth and have important applications in ultrafast process analysis, optical pulse sampling, and optical communications.
我们研究了色散元件的三阶色散、三光子吸收和自由载流子效应，对通过${\rm Si}{0.8}{\rm Ge}{0.2}$硅锗波导中的四波混频（FWM）实现的中红外时间放大的影响。研究发现，这些因素会严重扭曲放大后的波形，并降低转换效率，主要原因是非线性吸收。提出了一种基于${\rm Si}{0.8}{\rm Ge}{0.2}$硅锗波导中四波混频的时间透镜，用于中红外超短脉冲的时间放大，通过优化系统参数可在时域中获得低失真、高放大率。这些结果使得通过具有吉赫兹带宽的示波器和探测器来分析瞬态动态过程成为可能，并在超快过程分析、光脉冲采样和光通信中具有重要应用。
