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Proceedings Paper

Design of laser source for fiber point diffraction interferometer
Author(s): Xun Yu; Liang Nie; Jun Han; Baoyuan Liu; Xu Jiang
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Paper Abstract

The fiber point-diffraction interferometer is introduced for measuring spherical surface with high precision. The interferometer must use special laser source, the coherence length of which is no more than 10 cm. The laser source at present can not meet the demand and the research of laser source design is performed in this paper. The coherence length of laser source in experiment is inconsistent with that computed with general theory, which restrict the research progress. In this paper, Mutual Coherence Function is introduced to describe the coherence of optical field. Based on the spectral characteristic of laser source, the mode of Multi-Longitudinal Mode laser is built. Through numerical calculation, it is discussed that how coherence degree is related with Longitudinal Mode number, spectral half width and resonant cavity length. Some important conclusions are draw. For example, Multi-Longitudinal Mode laser source has periodic coherence degree no matter how many longitudinal modes it contains, and the period of laser coherence degree is always double resonant cavity length. The method for designing short coherence length laser is put forward based on the conclusions and its coherence is measured in experiment. The result shows that the coherence length reaches 5 cm and meets the need of the interferometer.

Paper Details

Date Published: 3 October 2008
PDF: 8 pages
Proc. SPIE 7155, Ninth International Symposium on Laser Metrology, 71552S (3 October 2008); doi: 10.1117/12.814602
Show Author Affiliations
Xun Yu, Xi'an Technological Univ. (China)
Liang Nie, Xi'an Technological Univ. (China)
Jun Han, Xi'an Technological Univ. (China)
Baoyuan Liu, Xi'an Technological Univ. (China)
Xu Jiang, Xi'an Institute of Applied Optics (China)

Published in SPIE Proceedings Vol. 7155:
Ninth International Symposium on Laser Metrology
Chenggen Quan; Anand Asundi, Editor(s)

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