Multi-channel Si-liquid crystal filter with fine tuning capability of individual channels for compensation of fabrication tolerances
1 Department of Electronic and Electrical Engineering, Trinity College Dublin, College Green, Dublin 2, Ireland
2 Ioffe Physical Technical Institute, Polytechnicheskaya 26, St. Petersburg, 194021, Russia
3 Department of Electronic and Communications Engineering, Dublin Institute of Technology, Kevin St, Dublin 8, Ireland
Nanoscale Research Letters 2012, 7:387 doi:10.1186/1556-276X-7-387Published: 12 July 2012
In this study, a technique for the optimization of the optical characteristics of multi-channel filters after fabrication is proposed. The multi-channel filter under consideration is based on a Si photonic crystal (PhC), tunable liquid crystal and opto-fluidic technologies. By filling air grooves in the one-dimensional, Si-Air PhC with a nematic liquid crystal, an efficiently coupled multi-channel filter can be realised in which a wide stop band is used for channel separation over a wide frequency range. By selectively tuning the refractive index in various coupled cavities, continuous individual tuning of the central channel (or edge channels) up to 25% of the total channel spacing is demonstrated. To our knowledge, this is the first report on the electro-optical solution for the compensation of fabrication tolerances in an integrated platform.