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Proceedings Paper

Highly sensitive biochemical sensor utilizing Bragg grating in submicron Si/SiO2 waveguides
Author(s): Saurabh Mani Tripathi; Arun Kumar; Jean-Pierre Meunier; Emmanuel Marin
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Paper Abstract

We present a novel highly sensitive biochemical sensor based on a Bragg grating written in the cladding region of a submicron planar Si/SiO2 waveguide. Owing to the high refractive index contrast at the Si/SiO2 boundary the TM modal power is relatively high in low refractive index sensing region, leading to higher sensitivity in this configuration [1]. Waveguide parameters have been optimized to obtain maximum modal power in the sensing region (PSe) and an optimum core width corresponding to maximum sensitivity is found to exist while operating in TM mode configuration, as has been shown in Fig. 1. It has been found that operating in TM mode configuration at optimum core width the structure exhibits extremely high sensitivity, ~ 5×10-6 RIU - 1.35×10-6 RIU for the ambient refractive indices between 1.33 - 1.63. Such high sensitivities are typically attainable for Surface Plasmon Polariton (SPP) based biosensors and is much higher than any non SPP based sensors. Being free from any metallic layer or bulky prism the structure is easy to realize. Owing to its simple structure and small dimensions the proposed sensor can be integrated with planar lightwave circuits and could be used in handy lab-on-a-chip devices. The device may find application in highly sensitive biological/chemical sensing areas in civil and defense sectors where analyzing the samples at the point of need is required rather than sending it to some centralized laboratory.

Paper Details

Date Published: 5 May 2009
PDF: 11 pages
Proc. SPIE 7316, Fiber Optic Sensors and Applications VI, 73160J (5 May 2009); doi: 10.1117/12.818464
Show Author Affiliations
Saurabh Mani Tripathi, Indian Institute of Technology Delhi (India)
Arun Kumar, Indian Institute of Technology Delhi (India)
Jean-Pierre Meunier, Univ. Jean Monnet Saint-Etienne (France)
Emmanuel Marin, Univ. Jean Monnet Saint-Etienne (France)

Published in SPIE Proceedings Vol. 7316:
Fiber Optic Sensors and Applications VI
Eric Udd; Henry H. Du; Anbo Wang, Editor(s)

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