Analysis of the guided modes in slab-coupled waveguides using a variational method

The waveguiding properties of the slab-coupled waveguides (i.e., the optical stripline and the rib waveguide) are investigated by the vector variational method. The slab-coupled waveguides are low-loss optical waveguides which are easy to fabricate and design. In this paper, the propagation constants and the field intensity distributions of the slab-coupled waveguides are presented, and the effects on the wave-guiding properties caused by changing their geometrical parameters are discussed. The results obtained by employing the variational method are compared with those obtained by using other methods.