啁啾光纤光栅在硫系光纤激光器中的色散补偿

Dispersion compensation of chirped fiber grating in chalcogenide fiber laser

中红外波段包含极其重要的大气窗口和众多分子的指纹区,基于硫系玻璃的中红外光纤激光器逐渐引起人们的重视。由于硫系玻璃具有极高的非线性和色散特性,脉冲激光在硫系光纤中的展宽成为发展中红外超短激光必须解决的重要问题。针对脉冲激光在硫系光纤中传输的展宽问题,设计线性啁啾光纤光栅,用于补偿高斯脉冲激光经过光纤之后的色散展宽。模拟结果表明:光纤色散导致的脉冲展宽可以通过线性啁啾光纤光栅进行很好的补偿。进一步研究发现,通过对设计的啁啾光纤光栅运用高斯变迹函数进行切趾优化,可以显著改善色散补偿的效果,以获得对脉冲激光色散展宽的完全补偿。文中的研究对于设计高质量的硫系中红外光纤激光器具有理论指导意义。

The mid infrared region covers the extraordinarily important atmospheric windows and has a wide range of molecular fingerprints, which has made the MIR laser based on chalcogenide glass attract considerable interest. In the development of infrared ultrashort laser, the solution of laser pulse broadening in chalcogenide glass fiber is critical, due to the high nonlinearity and dispersion properties of chalcogenide glass （ChG）. In the paper, in order to settle the broadening of laser pulse, the chirped fiber grating was designed to compensate dispersion stretching of Gaussian pulse lasers due to transmitting in the fiber. The study shows that the dispersion caused by pulse broadening can be well compensated by chirped fiber grating. Further investigation suggests that the chirped fiber grating are optimized by using Gaussian apodization function to improve dispersion compensation and realize complete compensation to dispersion broadening. The research is a beneficial exploration to the design of high-quality chalcogenide mid-infrared fiber lasers and of theoretical significance.