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29 October 1989 Dual Wavelength Intensity Modulated Optical Fibre Sensor System
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Proceedings Volume 1120, Fibre Optics '89; (1989)
Event: Sira/Fibre Optics '89, 1989, London, United Kingdom
A novel dual wavelength intensity modulated optical fibre displacement sensor system is described which employs a single Graded Index (GRIN) rod lensed fibre together with an interference filter and moving mirror element in the sensing head. The dual wavelength approach essentially utilises two spectral slices for a single LED transmission spectrum to provide the measurand and reference signals. In this way the sensor system is fully referenced for all major common-mode variations that may be present within the system components. The terminal transceiver unit is also discussed together with a specially designed LED coupler and demultiplexer device which enables the system to operate with a single fibre connection. The performance characteristics of the prototype dual wavelength sensor system are reported showing a linear displacement range over some 20 mm. In addition the coupling of the sensing head to a Bourdon tube is described which provides accurate pressure measurement over a range 3-15 psi. Finally an initial investigation of the immunity of the system to common-mode variations is presented using the mechanism of fibre bend loss.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. M. Senior, G. Murtaza, A. I. Stirling, and G. H. Wainwright "Dual Wavelength Intensity Modulated Optical Fibre Sensor System", Proc. SPIE 1120, Fibre Optics '89, (29 October 1989);

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