The Formation of Fringes of Equal Chromatic Order across Double Clad Fiber in the Presence of High Power Lasers

Mona F Omar,Rania H Abd El-Maksoud

doi:10.4236/opj.2016.62005

Abstract

Multiple-beam fringes of equal chromatic order interferometry is a powerful technique to extract optical properties over a continuous range of spectrum. In this paper we develop a theory for the spectral shape of the fringes of equal chromatic order (FECO) that are formed across a double-clad fiber. The modified single term Sellmeier dispersion formula is used to construct the refractive index dispersion curves for the liquid, claddings, and core. Expressions for the paraxial optical path length for several rays passing through the fiber and the liquid are developed. The condition of bright fringe is applied to get an analytical expression for the spectral shape of the FECO across a double-clad fiber with an elliptical/circular inner cladding. A potential application of this theory is to determine the dispersion of Kerr constant of the claddings and the core of the fiber. To illustrate the theory and its application, simulation examples are provided and discussed.

Highlights

Multiple-beam fringes of equal chromatic order (FECO) are formed when white light source illuminates a silvered air wedge
A great advantage of the FECO interferometry is that a single interferogram gives the required information to deduce the fiber optical parameters across the visible spectrum
We provide an understanding of the formation of the FECO across DCF and we discuss some of its applications

Summary

Introduction

Multiple-beam fringes of equal chromatic order (FECO) are formed when white light source illuminates a silvered air wedge. (2016) The Formation of Fringes of Equal Chromatic Order across Double Clad Fiber in the Presence of High Power Lasers. A great advantage of the FECO interferometry is that a single interferogram gives the required information to deduce the fiber optical parameters across the visible spectrum. Barakat et al derived a mathematical expression for the shape of Fizeau fringes and FECO crossing an optical fiber with single circular cladding [4] [5]. Medhat et al used the FECO to measure the dispersion curve of optical fibers with single cladding [6] [7]. Medhat et al studied theoretically and experimentally the effect of the temperature and Gamma radiation on the dispersion curve of optical fibers with single cladding [8] [9].

Theory

Simulation Example

Potential Applications

Conclusion