Guided propagation in a step-index, multi-mode fiber: effect of index difference variation on allowable TM propagation constants

The effect of variation of core and cladding index difference, Delta n = n( core) - n(cladding), on allowable values for the guided mode transverse mag netic propagation constants within a step-index, multi-mode optical fiber i s investigated. We use a iterative computational technique to calculate the propagation constants for modes inside and outside the core that satisfy t he boundary conditions contained within the characteristic eigen-equation f or the TM field components. Evidence of a strong dependence of the allowabl e propagation constants on changes of Delta n is shown. (C) 1999 Elsevier S cience Ltd. All rights reserved.