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Proceedings Paper

Transmission/Reflection Filter For Double Sideband IR Waveguide Modulators
Author(s): R. T. Brown; P. K. Cheo; R. S. Eng
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Paper Abstract

For 10.6 μm laser radar systems which utilize a double sideband modulator as a local oscillator frequency shifter in the receiver section, it is necessary to remove the carrier signal and the unwanted sideband signal prior to routing the frequency-shifted radiation to the heterodyne detector. This paper discusses the use of a reflective-mode Fabry-Perot etalon in conjunction with an optical duplexer to remove the carrier signal. The duplexer is a thin-film polarizer together with a quarter-wave plate. Since the sideband-to-carrier power out of the modulator is typically a few percent, it is imperative that mirror surface error and finite coating reflectivity be properly accounted for in order to achieve an adequate filter design. A rejection ratio corresponding to 20 dB between the laser carrier and the sideband was measured for the present design.

Paper Details

Date Published: 18 February 1989
PDF: 9 pages
Proc. SPIE 0999, Laser Radar III, (18 February 1989); doi: 10.1117/12.960224
Show Author Affiliations
R. T. Brown, United Technologies (United States)
P. K. Cheo, United Technologies (United States)
R. S. Eng, Lincoln Lab./MIT (United States)

Published in SPIE Proceedings Vol. 0999:
Laser Radar III
Richard J. Becherer, Editor(s)

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