SOI Waveguides

Modelling the high refractive index contrasts associated with silicon photonics and silicon waveguides (or silicon-on-insulator SOI waveguides) is a challenge that requires fully vectorial simulation tools. FIMMAVE allows you to model silicon waveguides accurately and efficiently thanks to its fully vectorial mode solvers, and to calculate mode losses for bend modes and leaky modes in silicon photonics.

We will show here how FIMMWAVE can be used to simulate a wide range of silicon rib waveguides. Please note that similar calculations can be performed on buried silicon waveguides, ridge silicon waveguides and other geometries.

The FMM Solver was used to find the modes of a polarisation-independent structure. The mode profiles for the fundamental TE-like and TM-like modes are plotted below.

The FMM Solver being fully vectorial, it allows you to observe effects such as optical leakage of the minority field. You will find an example below, in which the first order TM-like mode is guided for the main (Ey) field component but leaky for the minority (Ex) field component.

A wide range of parameters can be calculated for each mode, including the effective index, group index, mode dispersion and mode loss in the case of leaky modes or bend modes. All these parameters can be scanned with varying geometry of the waveguide, allowing to fine-tune the design of the SOI for specific purposes.

Examples of SOI optimisation with FIMMWAVE include polarization-independence, low bending loss and single-mode propagation. The thermo-optic module also allows you to design SOI thermo-optic switches in 3D. Successful attempts to obtain simultaneously polarization independence and single-mode propagation using FIMMWAVE are for instance reported in [1].

You can see how the bend modes of this waveguide were calculated with the FMM Solver here.

[1] L. Vivien, S. Laval, B. Dumont, S. Lardenois, A. Koster, E. Cassan, “Polarization-independent single-mode rib waveguides on silicon-on-insulator for telecommunication wavelengths”, Optics Communications 210, pp. 43-49, Sept 2002

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