Variational analysis of single-mode graded-core W-fibers

A new trial function is proposed to obtain the propagation constant, the normalized group delay, and the modal dispersion parameter of single-mode graded-core W-type fibers. This function uses only simple elementary functions to approximate the fundamental modal fields. In many cases of study, we show that the present trial function gives a significant improvement over the existing trial functions and is very useful in the analysis of fibers and related devices.