Variational method in the study of optical fibres

The dispersion characteristics are needed to evaluate the performance of optical fibres. In general, these will have to be obtained numerically. For this, a computationally fast method is required which will give accurate values of the propagation constants (eigenvalues). In this work, the variation method is used with the propagation equation imposed as a constraint. This method is computationally fast and gives accurate results. In an earlier work, the LP01 mode had been dealt with for the parabolic-profile fibre and it was speculated that the same method could be extended to the higher-order modes. In the present work, the LP11 and LP12 modes have been dealt with by the same method for the parabolic-profile fibre, thus confirming the speculation. © 1991 Taylor & Francis Group, LLC.