Two mixed methods for the analysis of a multimode optical rib waveguide

A new technique is developed for calculating the dispersion characteristics and field distribution of a multimode rib optical waveguide. The technique is based on the combination of the effective index and the variational methods. An algorithm is implemented to study the effect of the structure parameters and dimensions on the dispersion curves for quasi-TE and TM-modes of a rib optical waveguide. The field distribution of the fundamental and higher order modes for the two cases are also computed. The obtained results are compared with other published data where good agreement is found.