Single-mode Graded Index Fiber Directional Coupler: Analysis by a Simple and Accurate Method

Abstract

We present simple and accurate analysis of coupling characteristics of identical single-mode graded index fiber directional couplers. Our analysis is based on the recently developed simple series expression for the fundamental mode of such a fiber involving Chebyshev technique. Analytical expressions of the relevant parameters are presented and the concerned calculations are executable with much less computations. With examples of step and parabolic index fiber directional couplers we show that our estimations match excellently with the exact results.

Accurate Estimate of Some Propagation Characteristics for the First Higher Order Mode in Graded Index Fiber with Simple Analytic Chebyshev Method

“…The Chebyshev power series technique which is used in the case of single-mode graded index fiber is already established as a simple and accurate approximate analytic method [7][8][9][10]. It is used to predict fractional power guided through the core, excitation efficiency and Petermann I and II spot sizes for the first higher order mode of step index fiber (SIF) and parabolic index fiber (PIF) [11].…”