Application of modified finite-difference formulas to the analysis of z-variant rib waveguides

Modified finite-difference formulas for a general position of an interface are applied to the propagating beam analysis of z-variant rib waveguides. The modified formula based on the semivectorial H-field is found to be more insensitive to variation in an interface position than that on the E-field. A discretization error is satisfactorily reduced in tilted and tapered rib waveguides.