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Optical Engineering

Short-range remote spectral sensor using mid-infrared semiconductor lasers with orthogonal code-division multiplexing approach
Author(s): Zulfikar Morbi; D. B. Ho; H.-W. Ren; Han Q. Le; Shin Shem Pei
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Paper Abstract

Demonstration of short-range multispectral remote sensing, using 3 to 4-?m mid-infrared Sb semiconductor lasers based on codedivision multiplexing (CDM) architecture, is described. The system is built on a principle similar to intensity-modulated/direct-detection optical- CDMA for communications, but adapted for sensing with synchronous, orthogonal codes to distinguish different wavelength channels with zero interchannel correlation. The concept is scalable for any number of channels, and experiments with a two-wavelength system are conducted. The CDM-signal processing yielded a white-Gaussian-like system noise that is found to be near the theoretical level limited by the detector fundamental intrinsic noise. With sub-mW transmitter average power, the system was able to detect an open-air acetylene gas leak of 10-2 STPft3/hr from 10-m away with time-varying, random, noncooperative backscat- ters. A similar experiment detected and positively distinguished hydrocarbon oil contaminants on water from bio-organic oils and detergents. Projection for more advanced systems suggests a multi-kilometer-range capability for watt-level transmitters, and hundreds of wavelength channels can also be accommodated for active hyperspectral remote sensing application.

Paper Details

Date Published: 1 September 2002
PDF: 17 pages
Opt. Eng. 41(9) doi: 10.1117/1.1497614
Published in: Optical Engineering Volume 41, Issue 9
Show Author Affiliations
Zulfikar Morbi, Univ. of Houston (United States)
D. B. Ho, Univ. of Houston (United States)
H.-W. Ren, Univ. of Houston (United States)
Han Q. Le, Univ. of Houston (United States)
Shin Shem Pei, Univ. of Houston (United States)


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