Model of Vernier devices in silicon-on-insulator technology

• A 3D FVFD model, specifically suited for high index contrast and smaller size waveguides, is presented.
• The model of coupling length is developed based on 3D FVFD, and verified by the experiments.
• Detailed and thorough simulations of Vernier devices are discussed.

In order to increase the number of channels that could be multiplexed or demultiplexed in the dense wavelength division multiplexed (DWDM) system based on the resonators on silicon-on-insulator (SOI) technology, the Vernier effect in the series-coupled racetrack resonators is presented to extend the free spectral range (FSR) of the DWDM systems. A method is developed based on a matrix approach to simulate Vernier devices. A three-dimensional full vectorial finite difference (FVFD) model, specifically suited for high index contrast and smaller size waveguides, for example, a waveguide in SOI technology, is developed to obtain the properties of a waveguide. Finally, the Vernier effect in the two series-coupled racetrack resonators is experimentally verified with an improved FSR and interstitial resonance suppression.