FIMMWAVE

Modes of Slot Waveguides

Simulation of silicon cross-slot waveguide with FIMMWAVE software

FIMMWAVE's mode solvers were used to calculate the modes of a silicon cross-slot waveguide; slot waveguides use a combination of high-index and low-index layers to generate light confinement.

FIMMWAVE can be used to model any slot waveguide geometry built from any materials, including silicon, polymer and hybrid slot waveguides. The silicon cross-slot waveguide presented here is taken from an article from Helsinki University of Technology [1], featuring FIMMWAVE simulations. The paper also presents results for waveguide geometries with angled sidewalls.

See also [2], also featuring FIMMWAVE simulations for the modelling of slot waveguides.

Silicon slot waveguide designed in FIMMWAVE

The modes of the silicon slot waveguide were calculated using FIMMWAVE's fully vectorial FDM Solver. The calculation only took a few seconds, and the solver was able to take advantage of the waveguide symmetry.

This waveguide is a single-mode waveguide, and the fundamental TE-like mode and TM-like mode are shown below. You can see clearly how the cross-slot geometry generates a 90-degree rotation of the field distribution between the two polarisations. FIMMWAVE can also provide a large number of mode properties, including effective index, propagation constant, group index, dispersion, polarisation, effective mode area, confinement factor etc.

Properties of the fundamental TE-like mode of the silicon cross-slot waveguide:
(clockwise from top-left) intensity profile, Ex field profile and horizontal section, mode properties

Properties of the fundamental TM-like mode of the silicon cross-slot waveguide:
(clockwise from top-left) intensity profile, Ey field profile and horizontal section, mode properties

FIMMWAVE allows you to check the accuracy of your calculation as it features three independent fully-vectorial Cartesian mode solvers: the FMM, FDM and FEM Solvers. We ran the simulation with all three solvers and found the results to be in excellent agreement.

FIMMPROP, the propagation tool associated with FIMMWAVE, can also be used to model light propagating within slot-waveguide structures.

References

[1] A. Khanna, A. Säynätjoki, A. Tervonen and S. Honkanen, "Control of optical mode properties in cross-slot waveguides", Applied Optics 48, 34, pp. 6547-6552 (2009)

[2] M.P. Hiscocks, C. Su, B. Gibson, A.D. Greentree, L.C.L. Hollenberg, and F. Ladouceur, "Slot-waveguide cavities for optical quantum information applications", Optics Express 17, 9, p7295-7303 (2009)

More publications 

Click here to find publications that include FIMMWAVE simulations of slot waveguides on Google Scholar.