Flexible Optical Waveguide Bent Loss Attenuation Effects Analysis and Modeling Application to an Intrinsic Optical Fiber Temperature Sensor

Mustapha Remouche,Patrick Meyrueis,Francis Georges

doi:10.4236/opj.2012.21001

Abstract

The temperature dependence of the bending loss light energy in multimode optical fibers is reported and analyzed. The work described in this paper aims to extend an initial previous analysis concerning planar optical waveguides, light energy loss, to circular optical waveguides. The paper also presents a novel intrinsic fiber optic sensing device base on this study allowing to measure temperatures parameters. The simulation results are validated theoretically in the case of silica/silicone optical fiber. A comparison is done between results obtained with an optical fiber and the results obtained from the previous curved optical planar waveguide study. It is showed that the bending losses and the temperature measurement range depend on the curvature radius of an optical fiber or waveguide and the kind of the optical waveguide on which the sensing process is implemented.

Highlights

A curvature effect is reached with optical fibers; many laboratories have investigated the effects of curvatures on optical fiber measuring responses
It is showed that the bending losses and the temperature measurement range depend on the curvature radius of an optical fiber or waveguide and the kind of the optical waveguide on which the sensing process is implemented
It has been found that the bending losses due to the internal optical fiber numerical aperture variations increase when the fiber bending angle increase

Summary

Introduction

A curvature effect is reached with optical fibers; many laboratories have investigated the effects of curvatures on optical fiber measuring responses. In previous paper [1], we described a geometrical method to determine the local numerical aperture and the light output power attenuation with the bending of an optical waveguide We showed that this method can be applied only when the optical waveguide is curved during the manufacturing at a temperature close to glass melting. The core and the cladding refractive index are modified by temperature effects independently of the curvature radius In this a previous work [1], we described a set of methods for using a flat optical waveguide as a transducer for measuring temperature by bending, in which only some transmitted light intensity effects are involved. In this case the geometrical approach is similar to the one presented for the planar waveguide sensing modeling

Analysis If the Power Attenuation with the Bending of an Optical Fiber

Bent Optical Fiber Temperature Response as a Sensor

Conclusion