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Optical Engineering

Active heterodyne interferometric displacement measurement using optical feedback effects of laser diodes
Author(s): Norihiko Takahashi; Seiichi Kakuma; Ryoji Ohba
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Paper Abstract

A novel method is presented for precision displacement measurement based on active heterodyne interferometry. A pair of laser diodes, each of which is equipped with an external cavity, are used as light sources. A small displacement of a piezoelectric transducer, which carries the reflecting mirror of the external cavity, causes lasing frequency shift due to optical feedback on the laser diode. Detection of the optical frequency shift is accomplished by a heterodyne arrangement. Direct counting of the heterodyne beat frequency enables precise measurement of a dynamic displacement without any complex numerical calculation. Excellent performance of the presented method is illustrated by experimental results on the measurement for small displacement with an accuracy of ±5 nm and a time resolution of 33 ms.

Paper Details

Date Published: 1 March 1996
PDF: 6 pages
Opt. Eng. 35(3) doi: 10.1117/1.601026
Published in: Optical Engineering Volume 35, Issue 3
Show Author Affiliations
Norihiko Takahashi, Hokkaido Univ. (Japan)
Seiichi Kakuma, Hokkaido Univ. (Japan)
Ryoji Ohba, Hokkaido Univ. (Japan)

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