FIBER OPTIC EVANESCENT FIELD ABSORPTION SENSOR WITH HIGH-SENSITIVITY AND LINEAR DYNAMIC-RANGE

A novel fiber optic evanescent field absorption sensor having high sen sitivity and linear dynamic range is proposed. High sensitivity is ach ieved by using a U-shaped probe while linear response is obtained by p reventing surface reactivity of the silica core of the fiber with the solute molecules of the absorbing fluid. To prevent it, a thin film of a suitable polymer is developed on the bare core U-shaped probe. A go od degree of reproducibility of the results is obtained. (C) 1998 Else vier Science B.V. All rights reserved.