Abstract

In order to improve speed in computing the mode indices and, increase accuracy, a fast algorithm is proposed to solve the WKB implicit equation in planar optical graded-index waveguides. It is based on the secant method which is iterative and uses an initial guess to start computation. The main goal of the algorithm is to find the best initial guess which leads to the accurate value of the effective index with the minimum of error. To do that, the implicit WKB equation is given in terms of normalized propagation constant b. Any value of b between zero and unity becomes an initial guess and, leads to a value of effective index. The accurate solution is given for a minimum of error.

© 2003 Optical Society of America