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Proceedings Paper

Linear frequency modulation with electronic-optics modulator
Author(s): Changqing Cao; Xiaodong Zeng; Yili Zheng; Huanhuan Liu; Xiaoyan Zhao
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Paper Abstract

The spatial resolution of a space communication system is constrained by the diffraction limit of the telescope aperture. In a frequency-modulated continuous wave (FMCW), the frequency of the laser is ramped, and the frequency difference between the reflected wave and a local-oscillator wave is monitored. For maximum performance the frequency ramping should be linear. Linear frequency modulation (LFM) of the laser emission is a commonly used method for improving the detection sensitivity. Because of the available technology, techniques that use relatively low modulation frequencies were implemented first. In the early 1980's, an elegant measurement method based on frequency modulation opened up new applications for spectroscopy with spectrally modulated laser light. In this paper we analyzed systematically the principles of saw tooth-wave optical FMCW. For optical FMCW, because all the practical optical waves are from single-mode lasers, and because the laser beam from a single-mode laser is coherent in space due to the nature of stimulated emission, the spatial coherence is always satisfied, and therefore only temporal coherence need be considered. The chip signal, experimental system, and results are analyzed and discussed.

Paper Details

Date Published: 19 November 2007
PDF: 9 pages
Proc. SPIE 6782, Optoelectronic Materials and Devices II, 678239 (19 November 2007); doi: 10.1117/12.741533
Show Author Affiliations
Changqing Cao, Xidian Univ. (China)
Xiaodong Zeng, Xidian Univ. (China)
Yili Zheng, Xidian Univ. (China)
Huanhuan Liu, Xidian Univ. (China)
Xiaoyan Zhao, Xidian Univ. (China)


Published in SPIE Proceedings Vol. 6782:
Optoelectronic Materials and Devices II
Yoshiaki Nakano, Editor(s)

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