An optical fibre sensor for particle concentration measurement in water systems based on inter-fibre light coupling between polymer optical fibres

• Published in: Transactions of the Institute of Measurement and Control Vol. 22; no. 5; pp. 413 - 430
• Main Authors: Zhang, F. H., Lewis, E., Scully, P. J.
• Format: Journal Article
• Language: English
• Published: Thousand Oaks, CA SAGE Publications 01-12-2000
• Subjects: optical fibre sensors; water quality monitoring; polymer optical fibres; particle concentration measurement; evanescent wave sensors
• ISSN: 0142-3312; 1477-0369
• DOI: 10.1177/014233120002200506

An optical fibre sensor has been developed to measure particle concentration in water. The principle of operation is based on light being coupled between two parallel mounted fibres in the vicinity of the sensing region. The optical power is coupled by means of the evanescent field of the multimode fibres. A theoretical description of the light propagation mechanism in the fibre is presented which is extended to include the effect of attenuation of the evanescent wave in the measurand medium. Experimental results are also presented for yeast suspensions in water in the range 0-16 gl-
1.