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Proceedings Paper

Remote laser interferometer with pseudo-heterodyne signal processing
Author(s): Leonid B. Liokumovich; Sergey I. Markov
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Paper Abstract

Optic and fiber optic interference (phase) scheme are successfully used in creating of hydro-acoustic sensors, vibration sensors and measurers of other magnitudes. The most actual type of the interference sensors is a construction which utilize remote passive all optics sensitive interferometer (Fig. 1). In such devices the additional phase modulation and special methods of signal processing are traditionally used. The resolution of the interference sensor is limited by the noise factor of its elements. The final output noise level of the sensor depends of the optical scheme and method of signal processing. This report is devoted to the neutralization of the influence of the light intensity fluctuations on the sensor resolution using pseudo-heterodyne signal processing. Suppression of this factor in phase optical sensors is not often discussed in literature because laser intensity noise is usually insignificant relatively to other noise mechanisms. However in remote sensors with long distance between signal processing unit and sensitive element we have another situation. External influence (acoustics, vibrations) on lead in and lead out optical paths gives an essential income in the intensity noise at the optics exit. This income is especially sizable (up to tens percents) in remote sensors with opened air optical lead in and out. Sometimes they can even make signal measuring impossible.

Paper Details

Date Published: 27 November 2000
PDF: 4 pages
Proc. SPIE 4316, International Conference on Lasers for Measurements and Information Transfer, (27 November 2000); doi: 10.1117/12.407655
Show Author Affiliations
Leonid B. Liokumovich, St. Petersburg State Technical Univ. (Russia)
Sergey I. Markov, St. Petersburg State Technical Univ. (Russia)


Published in SPIE Proceedings Vol. 4316:
International Conference on Lasers for Measurements and Information Transfer
Vadim E. Privalov, Editor(s)

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