A method for the simulation of discontinuities in photonic crystal defect waveguides is presented. This frequency domain technique is based on the multiple multipole method. In contrast with other known techniques, spurious reflections (due to the impedance mismatch at the waveguide terminations) are avoided. The absence of spurious reflections allows one to characterize precisely the intrinsic...

Abstract. Coupling between the modes in a planar optical waveguide induced by a boundary step discontinuity, by a single groove and by a grating with arbitrary cross section, is investigated theoretically. Analytical expressions for the coupling mode coefficients are obtained by the mode-matching method, containing the angular dependence in explicit form for both TE and TM incidence. An analogy...

A generalized modal scattering matrix formulation is presented for the calculation of discontinuity-distorted waveguide multiport junctions. Unlike common approaches based on three-plane mode-matching techniques, and modifications thereof, which calculate only the fundamental-mode scattering matrix, this algorithm computes the generalized modal scattering matrix of the junction. Therefore, the ...

We demonstrate a fast, accurate for weak waveguiding, approximate solution to the problem of computing the modal reflection and transmission coefficients at a discontinuity between two asymmetric multilayer waveguides together with a rigorous solution to check the validity of the approximate but fast approach. The proposed algorithm is analogous to the widely used approximation proposed by Vass...

Abstract: Alteration of a geometry parameter in the cross section of a dielectric waveguide with piecewise constant permittivity profile can be regarded as a refractive index perturbation in a layer along a dielectric discontinuity line. Starting from these thin layer perturbations, we derive explicit expressions for partial derivatives of propagation constants with respect to the transverse wa...

A new canonical scattering problem consisting of the propagation of the dominant TEM mode at the finite-length impedance discontinuity in the outer conductor of a coaxial waveguide is solved. The contributions from the successive impedance discontinuities are accounted for through the solution of a modified Wiener-Hopf equation. Some graphical results displaying the reflection and transmission ...

Shifting the location of a dielectric boundary in the cross section of an integrated optical waveguide with piecewise constant refractive index profile results in a permittivity perturbation in a layer along the discontinuity line. On the basis of these thin layer perturbations, we discuss perturbational expressions for the derivatives of the propagation constants with respect to geometry param...