In displacement interferometry, beam delivery by optical fibres is an important issue as this enables to keep the laser source, which acts as a heating source, away from the path in which a displacement needs to be measured. A complication is the polarisation state of the laser beam, which needs to remain undisturbed as much as possible. We use a set-up in which a single polarisation-preserving fibre is used for both polarization directions which are used in heterodyne interferometry. To correct for strain- and temperature effects, a reference phase measurement is made after the fibre. Various types of polarisation-preserving fibres have been measured with regard to their polarisation-preserving properties. It is shown that with a good quality optical fibre and with proper alignment and phase-compensation methods, the remaining periodic non-linearities in a displacement measurement can be within a few nm.
|Title of host publication||Proceedings EUSPEN international topical conference on precision engineering, micro technology, measurement techniques and equipement : May 19-20, 2003, Aachen, Germany. Vol. 2|
|Editors||M. Weck, H. Kunzmann|
|Place of Publication||Germany, Aachen|
|Publication status||Published - 2003|