线性啁啾光纤布喇格光栅反射谱的数值模拟

为了研究线性啁啾光纤布喇格光栅的特性,并进一步把它用于光纤激光器上,介绍了线性啁啾光纤布喇格光栅的耦合模理论,采用4阶Runge-Kutta法和传输矩阵法结合控制变量法,对线性啁啾光纤布喇格光栅反射率与啁啾系数、半峰全宽与光栅长度、反射率与直流纤芯折射率改变量之间的关系进行了数值模拟。结果表明,线性啁啾光纤布喇格光纤可以展宽带宽。基于这个结论,提出了利用线性啁啾光纤布喇格光栅作为光纤激光器腔镜,使输出谱线展宽,从而可作为宽带光源使用的方案。

Numerical analysis of reflection spectrum of linearly chirped fiber Bragg gratings

In order to study the properties of linearly chirped fiber Bragg grating(LCFBG), and further use it in optical fiber lasers, the coupling theory of the LCFBG was introduced. By using four-order Runge-Kutta method, transfer matrix method and the control variable method, the dependence of reflectivity of the LCFBG on chirp coefficient, direct current index change spatially averaged over a grating period, and the dependence of full width at half maximum on the length of the LCFBG were simulated. The results show that linearly chirped fiber Bragg gratings can broaden the bandwidth. Based on this conclusion, the gratings are used as cavity mirrors of fiber lasers can expand the output spectrum, which can be used as a broadband light source.