A NEW LOOK AT NUMERICAL ANALYSIS OF UNIFORM FIBER BRAGG GRATINGS USING COUPLED MODE THEORY

The coupled mode theory (CMT) is used to analyze uniform Fiber Bragg gratings. The multi-mode CMT is expressed as the flrst-order vector ordinary difierential equations (ODEs) with coe-cients depending on the propagation distance. We show in this paper that by changing variables, the original couple mode equations (CMEs) can be re-casted as constant coe-cient ODEs. The eigenvalue and eigenvector technique (EVVT), the analytic method for solving constant coe-cient ODEs, is then applied to solve the coupled mode equations. Furthermore, we also investigate the application of Runge- Kutta method (RKM) to the calculation of the global transfer-function matrix for CMEs. We compare the transmission and the re∞ection