Ultra-sharp asymmetric Fano-like resonance spectrum on Si photonic platform

Du, H. et al. (2019) Ultra-sharp asymmetric Fano-like resonance spectrum on Si photonic platform. Optics Express, 27(5), pp. 7365-7372. (doi: 10.1364/OE.27.007365) (PMID:30876301)

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In this paper, we report the generation of an ultra-sharp asymmetric resonance spectrum through Fano-like interference. This generation is accomplished by weakly coupling a high-quality factor (Q factor) Fabry–Pérot (FP) cavity and a low-Q factor FP cavity through evanescent waves. The high-Q FP cavity is formed by Sagnac loop mirrors, whilst the low-Q one is built by partially transmitting Sagnac loop reflectors. The working principle has been analytically established and numerically modelled by using temporal coupled-mode-theory (CMT), and verified using a prototype device fabricated on the 340 nm silicon-on-insulator (SOI) platform, patterned by deep ultraviolet (DUV) lithography. Pronounced asymmetric resonances with slopes up to 0.77 dB/pm have been successfully measured, which, to the best of our knowledge, is higher than the results reported in state-of-the-art devices in on-chip integrated Si photonic studies. The established theoretical analysis method can provide excellent design guidelines for devices with Fano-like resonances. The design principle can be applied to ultra-sensitive sensing, ultra-high extinction ratio switching, and more applications.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Sorel, Professor Marc and Sharp, Mr Graham
Authors: Du, H., Zhang, W., Littlejohns, C.G., Stankovic, S., Yan, X., Tran, D.T., Sharp, G.J., Gardes, F.Y., Thomson, D.J., Sorel, M., Mashanovich, G.Z., and Reed, G.T.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Optics Express
Publisher:Optical Society of America
ISSN (Online):1094-4087
Published Online:27 February 2019
Copyright Holders:Copyright © 2019 Optical Society of America
First Published:First published in Optics Express 27(5): 7365-7372
Publisher Policy:Reproduced under a Creative Commons License
Data DOI:10.5258/SOTON/D0700

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
170847CORNERSTONE: Capability for OptoelectRoNics, mEtamateRialS, nanoTechnOlogy aNd sEnsingMarc SorelEngineering and Physical Sciences Research Council (EPSRC)EP/L021129/1ENG - Electronics & Nanoscale Engineering