Approximate Ritz-Galerkin Method for Field Distribution of Graded-Index Optical Fibers
求解梯度光纤模场的近似里兹-伽略金方法

Ritz-Galerkin method is used only for obtaining propagation constant and the radial mode field in core region of graded-index optical fibers.Cladding field has been constructed by using the accurate functional form (modified Bessel function) with two approximate parameters:the transverse decay constant in the cladding and the field value at core-cladding interface,which are already known.Numerical results show that the improvement on accuracy is significant.This approximate Ritz-Galerkin method has been applied to the calculation of coupling coefficient between two step-index optical fibers.Results are agreed well with exact values.