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Proceedings Paper

Characteristics of a high-resolution displacement sensor using mode interference in the optical waveguide
Author(s): Yutaka Iwasaki; Masaaki Doi; Takashi Shionoya; Kazuya Okamoto
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Paper Abstract

A high-resolution optical displacement sensing system using an optical waveguide is fabricated and characterized. The measurement principle is based on interference between an even and odd modes in the double-mode waveguide. After the light from a laser light source is focused onto the object to be measured, a wavefront gradient in the converged reflected light beam from the object gives a phase asymmetry at the entrance of the double-mode (DM) waveguide. A change of the phase asymmetry due to the displacement of the object along the optical axis is detected as a change of light intensity distribution at the exit of the DM waveguide. Although the optical system is very simple, experimental results using Ti-indiffused LiNbO3 waveguide device shows a very high resolution less than 1 nm. Next, a compact-type displacement sensor module using silica waveguide is fabricated and shows an identical high resolution. In conclusion, it will be very useful as a built-in component for various kinds of the industrial equipment.

Paper Details

Date Published: 1 April 1998
PDF: 8 pages
Proc. SPIE 3275, Flatness, Roughness, and Discrete Defects Characterization for Computer Disks, Wafers, and Flat Panel Displays II, (1 April 1998); doi: 10.1117/12.304390
Show Author Affiliations
Yutaka Iwasaki, Nikon Corp. (Japan)
Masaaki Doi, Nikon Corp. (Japan)
Takashi Shionoya, Nikon Corp. (Japan)
Kazuya Okamoto, Nikon Corp. (Japan)


Published in SPIE Proceedings Vol. 3275:
Flatness, Roughness, and Discrete Defects Characterization for Computer Disks, Wafers, and Flat Panel Displays II
John C. Stover, Editor(s)

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