Fiber-optical sensors have some crucial advantages compared with rigid optical systems. They allow miniaturization and flexibility of system setups. Nevertheless, optical principles such as low-coherence interferometry can be realized by use of fiber optics. We developed and realized an approach for a fiber-optical sensor, which is based on the analysis of spatially modulated low-coherence interferograms. The system presented consists of three units, a miniaturized sensing probe, a broadband fiber-coupled light source, and an adapted Michelson interferometer, which is used as an optical receiver. Furthermore, the signal processing procedure, which was developed for the interferogram analysis in order to achieve nanometer measurement accuracy, is discussed. A system prototype has been validated thoroughly in different experiments. The results approve the accuracy of the sensor.
© 2007 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: August 30, 2006
Revised Manuscript: February 1, 2007
Manuscript Accepted: February 1, 2007
Published: May 18, 2007
Frank Depiereux, Peter Lehmann, Tilo Pfeifer, and Robert Schmitt, "Fiber-optical sensor with miniaturized probe head and nanometer accuracy based on spatially modulated low-coherence interferogram analysis," Appl. Opt. 46, 3425-3431 (2007)