A CURVE-FITTING SIGNAL-PROCESSING SCHEME FOR A WHITE-LIGHT INTERFEROMETRIC SYSTEM WITH A SYNTHETIC SOURCE

A white-light interferometric system, which comprises two Michelson in terferometers linked by a 100 mu m diameter core multimode step index fibre has been investigated, where a signal processing scheme, using c urve fitting, has been introduced to suppress the noise induced in the system. The theoretical resolution of such a sensor with the use of a n appropriate curve fitting signal processing scheme has been discusse d. The experimental results obtained show the short term repeatability (to three standard deviations) to be better than 5 nm after signal pr ocessing, under conditions where the fibre is constantly vibrated in a known and reproducible way. (C) 1998 Published by Elsevier Science Lt d, All rights reserved.