Coupled-mode analysis of bent planar waveguides with finite claddings

Coupled-mode analysis of uniformly bent slab waveguides with finite claddings is demonstrated. Using the method of conformal transformation, a curved waveguide structure is translated into an equivalent straight waveguide with a modified asymmetric index profile. The wave propagation through this structure is described by coupled-mode formalism with ideal mode expansion. The step-index profiles as well as graded-index profiles are considered. The numerical results of transmitted power, wave propagation along the bend and pure bend loss are presented for TEo-mode excitation.