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Proceedings Paper

Misalignment measure error compensation in a passive phase-demodulated laser interferometer
Author(s): Ho-Pui Ho; Yuen Ming Chan; K C Lo; S Y Wu
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Paper Abstract

In this paper, we present a phase error correction algorithm for passive phase demodulation in Michelson interferometers. The key feature of the passive demodulation scheme is the incorporation of a grating (Ronchi) filter placed in front of optical detector. The filter is split into four quadrants and each of the quadrants imposes a 900phase shift. This quadrature feature offers single-step detection of phase information from the interference fringes, which are created by the superposition of the object and reference light beams. Our signal processing scheme incorporates first a diagonal subtraction, then followed by appropriate filtering and root mean square. In addition, this scheme can remove spurious intensity fluctuations induced by microphonics and unstable light source. An experimental setup has been constructed for demonstrating the operation ofthe proposed scheme. Simulation ofpossible errors due to grating misalignment and the effects on signal recovery will also be presented.

Paper Details

Date Published: 22 May 2002
PDF: 12 pages
Proc. SPIE 4827, Fifth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, (22 May 2002); doi: 10.1117/12.468163
Show Author Affiliations
Ho-Pui Ho, City Univ. of Hong Kong (Hong Kong)
Yuen Ming Chan, City Univ. of Hong Kong (China)
K C Lo, City Univ. of Hong Kong (Hong Kong)
S Y Wu, City Univ. of Hong Kong (Hong Kong)

Published in SPIE Proceedings Vol. 4827:
Fifth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications
Enrico Primo Tomasini, Editor(s)

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