CALCULATION OF MODE FIELD AND PROPAGATION CONSTANTS FOR GRADED-INDEX OPTICAL FIBERS BY USING COUPLED MODE THEORY
用耦合波理论求解渐变折射率光纤的传播常数和模式场

Propagation constant and modal field distribution for guided modes of an arbitrary graded index optical fiber have been calculated by using coupled mode theory. Taking the infinitely extended parabolic profile fiber as an ideal waveguide,an arbitrary radially inhomogeneous optical fiber can be viewed as a perturbation,its modal field can be expanded in terms of a complete set of ideal waveguide modes. Eigenvalues and modal fields are then obtained from coupled mode equations which have been transformed into a set of linear equations. Numerical results have been presented and compared with exact values.