SIMPLIFIED UNIVERSAL DISPERSION-CURVES FOR GRADED-INDEX PLANAR WAVE-GUIDES BASED ON THE WKB METHOD

A new way of normalizing the WKB equation for graded-index optical pla nar waveguides is presented. It is found that the normalized propagati on constant for the guided mode of a waveguide depends only on a singl e parameter, called the normalized mode order. For each profile shape, the new normalized WKB equation allows a single universal dispersion curve to be obtained that applies to all guided modes under all operat ing conditions. Examples are given for a number of practical profile s hapes. The present approach provides a particularly simple description of the dispersion characteristics of graded-index optical waveguides.