The fundamental mode of graded-index fibres: simple and accurate variational methods

In this paper, we present two approximations for the fundamental mode of graded-index fibres. The first is a one-parameter analysis which involves computational effort comparable to that involved in the Gaussian approximation and yet gives much better results. The second is a two-parameter analysis which gives much better results than other existing approximations for all values ofV for most graded-index fibres.Visiting from Physics Department, Ravenshaw College, Cuttack 753003, India.