论文部分内容阅读
提出了一种用于重建渐变折射率平板光波导折射率分布的方法,这种方法通过数值法求解亥姆霍兹方程,从光波导的低阶模开始采用迭代法顺次对各个模式对应的“转折点”位置进行校正,并多次重复迭代以消除“转折点”外折射率分布的变化对相应模式“转折点”位置的影响。借助WKB近似原理说明了这种方法迭代过程中“转折点”坐标的收敛性。对折射率按照指数规律变化的平板光波导的折射率分布重建结果证明这种方法具有较高的精度。分析表明这种方法克服了WKB法固有的缺陷,即忽略模式“转折点”外折射率分布对相应模式传输常量的影响和“转折点”处相移的不确定性,因而比逆WKB法具有更好的自洽性和精确性。
A method is proposed to reconstruct the refractive index profile of a graded-index slab optical waveguide. The method solves the Helmholtz equation by numerical method. From the low-order mode of the optical waveguide, The “turning point” position is corrected and repeated iteratively to eliminate the effect of changes in the refractive index distribution outside the “turning point” on the “turning point” position of the corresponding mode. The WKB approximation principle is used to illustrate the convergence of the “turning point” coordinates during the iteration of this method. The reconstruction of the refractive index distribution of the slab waveguide whose refractive index changes according to exponential law proves that the method has higher accuracy. The analysis shows that this method overcomes the inherent disadvantage of the WKB method by neglecting the influence of the refractive index distribution outside the mode “turning point” on the corresponding mode transfer constants and the phase shift uncertainty at the “turning point”, which is better than the inverse WKB method The consistency and accuracy.