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Proceedings Paper

Two-modality laser diode interferometer for high-accuracy measurement of long-range absolute distance
Author(s): Bofan Wang; Zhongliang Li; Xiangzhao Wang; Peng Bu
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Paper Abstract

This paper presents a two-modality laser diode (LD) interferometer which combine as two-wavelength sinusoidal phase modulating (SPM) interferometer with a wavelength scanning interferometer (WSI) for measurement of distance over long range with high accuracy. Moreover, the intensity modulation due to power changes of LD is suppressed by appropriately choosing the modulation amplitude of injection current (IC) of LD. Triangle wave is used to modulate the IC of one LD with that of the other LD being constant at first. Thus the interferometer works as a wavelength scanning interferometer. An initial estimate of the distance can be obtained from the phase change of the interference signal. Then sinusoidal wave is used for modulating IC of both LDs to realize a two-wavelength SPM interferometer. However, the modulation of the IC of two LDs results in not only the wavelength modulation but also the intensity modulation. This intensity modulation will cause a measured phase error. To eliminate this error, SPM depths are appropriately chosen, therefore the distance to be measured can be accurately obtained with synthetic-wavelength algorithm. Experimental results indicate that an absolute distance measurement accuracy of 1μm can be achieved over the range of 40mm to 100mm.

Paper Details

Date Published: 31 December 2010
PDF: 12 pages
Proc. SPIE 7544, Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 754447 (31 December 2010); doi: 10.1117/12.885662
Show Author Affiliations
Bofan Wang, Shanghai Institute of Optics and Fine Mechanics (China)
Graduate School of the Chinese Academy of Sciences (China)
Zhongliang Li, Shanghai Institute of Optics and Fine Mechanics (China)
Xiangzhao Wang, Shanghai Institute of Optics and Fine Mechanics (China)
Peng Bu, Shanghai Institute of Optics and Fine Mechanics (China)


Published in SPIE Proceedings Vol. 7544:
Sixth International Symposium on Precision Engineering Measurements and Instrumentation

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