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Optical Engineering

Heterodyne absolute distance interferometer with a dual-mode HeNe laser
Author(s): Yang Zhao; Ting Robert Zhou; Dacheng Li
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Paper Abstract

Theoretical considerations and experimental results related to the principle of dual-wavelength absolute distance interferometry (ADI) are presented. It is predicted that the required initial uncertainty of a length to be measured was related to the synthetic wavelength, its stability, and the length to be measured. An absolute distance measurement approach employing a dual-longitudinal-mode He-Ne laser is proposed. In this approach, a heterodyne interferometer with two acoustooptic modulators (AOMs) is used to directly measure the fractional fringe at the synthetic wavelength formed by them. The common optical path configuration in the simplified interferometer eliminates the influences that air turbulence and mechanical vibration have on measurement. Factors that influence measurement accuracy are analyzed theoretically and experimentally. Mode mixing is determined as the main influence on the accuracy of the approach, and the error caused by it can be compensated through data processing if the amount of mode mixing is fixed. Additionally, an experimental result is presented that obtains an accuracy of 140 ?m for 25 m.

Paper Details

Date Published: 1 February 1999
PDF: 4 pages
Opt. Eng. 38(2) doi: 10.1117/1.602273
Published in: Optical Engineering Volume 38, Issue 2
Show Author Affiliations
Yang Zhao, Tsinghua Univ. (United States)
Ting Robert Zhou, Tsinghua Univ. (United States)
Dacheng Li, Tsinghua Univ. (China)

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