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Applied Optics

Applied Optics


  • Vol. 22, Iss. 23 — Dec. 1, 1983
  • pp: 3787–3794

Precise comparison of experimental and theoretical SNRs in CO2 laser heterodyne systems

R. Foord, R. Jones, J. M. Vaughan, and D. V. Willetts  »View Author Affiliations

Applied Optics, Vol. 22, Issue 23, pp. 3787-3794 (1983)

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A detailed comparison of experimental and theoretical SNR in an IR laser heterodyne system has been made with three different signal analyzers. Good agreement, considerably better than a factor of 1.5, is reported. Accurate allowance was made for transmission in the receiver optics, the effective quantum efficiency of the detector due to shot noise domination by the local oscillator, and for coherent speckle effects across the collection aperture. The evaluation of SNR with a surface acoustic wave spectrum analyzer and digital integrator is described in some detail. As an illustration an absolute measurement of backscattering strength in the atmosphere from an airborne equipment at altitudes up to 13.1 km is provided.

© 1983 Optical Society of America

Original Manuscript: June 2, 1983
Published: December 1, 1983

R. Foord, R. Jones, J. M. Vaughan, and D. V. Willetts, "Precise comparison of experimental and theoretical SNRs in CO2 laser heterodyne systems," Appl. Opt. 22, 3787-3794 (1983)

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