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Multi-channel Si-liquid crystal filter with fine tuning capability of individual channels for compensation of fabrication tolerances

Anna Baldycheva1*, Vladimir A Tolmachev2, Kevin Berwick3 and Tatiana S Perova1*

Author Affiliations

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

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Nanoscale Research Letters 2012, 7:387  doi:10.1186/1556-276X-7-387

Published: 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.

Multi-cavity photonic crystal; Coupled Fabry-PĂ©rot resonators; Liquid crystal devices; Integrated optics devices; Wavelength filtering devices; Lithography error; Line-width variation; Critical dimension variation; 42.60.Da; Resonators; Cavities; Amplifiers; Arrays; Rings; 42.60.Fc; Modulation; Tuning; Mode locking; 42.70.Df; Liquid crystals