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Fluorescence-based fibre optic sensor systems for temperature and strain measurement

Sun, T. (1999). Fluorescence-based fibre optic sensor systems for temperature and strain measurement. (Unpublished Doctoral thesis, City, University of London)


Commencing with a review o f the development of fibre optic sensor technology and especially previous work in the phosphor thermometry area, this thesis covers research on fibre optic fluorescence thermometry. Several luminescent materials, e.g. crystalline materials, doped bulk glasses and rare-earth ion doped fibres, are evaluated. Theoretical models have been developed and are considered to provide underpinning support for the experimental results obtained, and applied to the optimization of the selection of particular suitable fluorescent materials for thermometric use, which lays an appropriate theoretical basis for the fluorescence thermometry discussed herein

The fluorescence based point temperature sensing system developed has been expanded to multi-point or quasi-distributed temperature sensing application by using Prony's method, which enables the exponential decays from either single material, two-material or even several element quasi-distributed sensors to be analyzed and thus data and associated measurand information encoded in each individual signal to be recovered.

As a further development, the fluorescence based system has been modified to measure average and local temperatures, which are important in a number of industrial situations. Corresponding signal processing schemes, the singular value (SV) scheme and the correlation coefficient ratio scheme, are introduced and tested to meet the requirement of high speed and consistency

Whilst recognizing their strong dependence on temperature variation, the fluorescence lifetimes o f rare earth doped fibres are investigated for the first time in terms of their sensitivity to another physical quantity, strain. Their characteristics and sensitivity are explored in detail in the work.

Finally, two most promising fluorescence-based temperature sensing techniques, namely the fluorescence intensity ratio (FIR) and fluorescence lifetime (FL) schemes, are compared and contrasted.

The significance of the work is considered and suggestions for future work made.

Publication Type: Thesis (Doctoral)
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering
Departments: School of Science & Technology > Engineering > Electrical & Electronic Engineering
School of Science & Technology > School of Science & Technology Doctoral Theses
Doctoral Theses
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