Title: Fibre Bragg gratings with one defect towards development of optical networks interrogators

Authors: Ignacio Del Villar, Ignacio R. Matias, Francisco J. Arregui

Addresses: Department of Electrical and Electronic Engineering, Public University of Navarra, Pamplona 31006, Spain. ' Department of Electrical and Electronic Engineering, Public University of Navarra, Pamplona 31006, Spain. ' Department of Electrical and Electronic Engineering, Public University of Navarra, Pamplona 31006, Spain

Abstract: A theoretical analysis is given of an interrogator scheme for detection of the shift in resonance wavelength of a Fibre Bragg grating- (FBG-)based device. An Active Wavelength Tunable Filter (AWTF) allows adjusting the filtering of the signal received to the resonance wavelength of the FBG and knowing at the same time the value of the resonance wavelength. This avoids the need for a spectrum analyser. The Wavelength Tunable Filter WTF) selected for the detection scheme is an FBG with a liquid crystal defect of optimised thickness whose refractive index is modified by the voltage applied, leading to a control of the central wavelength of the WTF. If the signal of several FBGs needs to be controlled, the scheme can be modified by using a Multiple Wavelength Tunable Filter (MWTF) consisting of as many WTFs as the number of FBG-based sensors or devices to be analysed.

Keywords: fibre Bragg gratings; tunable filters; coupled mode analysis; electrostatic self-assembly; ESA; optical fibre sensor networks; interrogator scheme; shift detection; resonance wavelength; liquid crystal defects; FBG-based sensors.

DOI: 10.1504/IJISTA.2007.014130

International Journal of Intelligent Systems Technologies and Applications, 2007 Vol.3 No.1/2, pp.119 - 132

Available online: 22 Jun 2007

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