光纤耦合模理论及其在光纤布拉格光栅上的应用

Coupled-Mode Theory for Optical Fiber and Its Application to Fiber Bragg Gratings

将正确的光纤中的正交关系应用于微扰耦合模理论得到了光纤中的微扰耦合模方程 ;并将其应用于光纤布拉格光栅 ,得到了一种新的耦合模方程。该方程中作为标志性特征的耦合系数与其它理论中的耦合系数都不相同。讨论了方程的解 ,得到了峰值反射率与布拉格波长、光栅长度之间的简单关系式。用光纤布拉格光栅进行了实验 ,理论和实验结果符合得很好。

The correct orthogonality relation for optical fiber is applied to the perturbed coupled-mode theory, and the corresponding coupled-mode equations for common optical fiber are introduced. Its application to fiber Bragg gratings is discussed. The coupling coefficients of the equations for fiber Bragg gratings, being the distinguished feature for coupled-mode theories, are different from other theories. The solutions of the equations are discussed, and the simple formula between the peak reflectivity and the Bragg wavelength, the length of the fiber Bragg grating is obtained. An experiment of fiber Bragg gratings is completed. The peak reflectivity of the experiment is about 0.993, and the corresponding theoretical result is 0.999. The experimental result coincides with the theory very well.