The technique of white light interferometry (WLI) is a powerful method in optical measurement systems. It involves the combination of two interferometers, coupled in series, and a light source of short coherence length. The displacement that is induced by the measurand in the first `sensor' interferometer is then determined in the second `recovery' interferometer with the advantage of a large unambiguous measurement range. The theoretical basis of the technique and practical realizations of the signal processing are considered. The potential of the system is discussed in terms of the measurement of displacement, and the technique is then applied to the measurement of other physical parameters, indicating various potential configurations of sensor elements for use ine in WLI systems. Results are presented illustrating its application in vibration, pressure, and position measurement.

Date Published: 15 November 1994
PDF: 9 pages
Proc. SPIE 2248, Optical Measurements and Sensors for the Process Industries, (15 November 1994); doi: 10.1117/12.194354

Published in SPIE Proceedings Vol. 2248:
Optical Measurements and Sensors for the Process Industries
Christophe Gorecki; Richard W. T. Preater, Editor(s)