A curve fitting signal processing scheme for a white-light interferometric system with a synthetic source

• Published in: Optics and laser technology 1997-10, Vol.29 (7), p.371-376
• Main Authors: Wang, Q., Ning, Y.N., Grattan, K.T.V., Palmer, A.W.
• Format: Article
• Language: English
• Subjects: Computers in experimental physics; curve fitting; Exact sciences and technology; Image processing; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Interferometers; interferometry; Measurements common to several branches of physics and astronomy; Metrology, measurements and laboratory procedures; Optical instruments, equipment and techniques; Physics; signal processing; Spatial dimensions (e.g.: position, lengths, volume, angles, displacements, including nanometer-scale displacements); Spatial dimensions (eg, position, lengths, volume, angles, displacements, including nanometer-scale displacements)
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/S0030-3992(97)00043-1

A white-light interferometric system, which comprises two Michelson interferometers linked by a 100 μm diameter core multimode step index fibre has been investigated, where a signal processing scheme, using curve fitting, has been introduced to suppress the noise induced in the system. The theoretical resolution of such a sensor with the use of an appropriate curve fitting signal processing scheme has been discussed. The experimental results obtained show the short term repeatability (to three standard deviations) to be better than 5 nm after signal processing, under conditions where the fibre is constantly vibrated in a known and reproducible way.