Numerical analysis of optical fibers using matrix approach

The authors conduct a numerical analysis of optical fibers characterized by arbitrarily graded, cylindrically symmetric refractive index profiles by transforming them into equivalent planar profiles and using a matrix approach developed earlier for the analysis of planar optical waveguides (see ibid., vol.5, p.660-7, 1987). The method, which involves only straightforward multiplication of 2×2 matrices, can be used to calculate the propagation constant, modal field profiles, leakage/absorption loss, etc. of fibres with arbitrarily graded profiles. The applicability of the method has been shown through calculations of propagation constant and modal fields of single-clad and coaxial step-index fibers. Calculations of leakage loss of LP₀₁ and LP₁₁ modes in depressed inner clad fibers have also been presented. The method was also used to determine the coupling length in a coaxial optical-fiber coupler, which has potential applications in optical-fiber sensing