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Proceedings Paper

Ground detectors for optical communications from deep space
Author(s): Abhijit Biswas; Beckett Madden-Woods; Meera Srinivasan; Victor Vilnrotter; William H. Farr
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Paper Abstract

A variety of avalanche photodiodes (APD's) were tested with pulse position modulated (PPM) Q-switched laser pulses incident on the detector, with varying amounts of attenuation. The detector output was recorded and post- processed in order to determine the signal and noise slot statistics, as well as, to estimate bit-error-rates (BER). The probability distribution functions predicted by a Webb+Gaussian model were compared to the measured slot statistics, as were theoretical BER curves. Allowing noise equivalent temperature to be a free fitting parameter yielded good fits between measurements and theory. All the measurements used 256-ary PPM and 10 - 25 ns slot widths, with a Q-switched Nd:YVO4 laser modulated at 50 K - 100 K pulses per second. A 3 mm diameter, silicon (Si) APD with 80% quantum efficiency (QE) at 532 nm displayed a sensitivity deteriorated to 18 photons/bit in the presence of 100 photons per 25 ns slot of background light. A 0.8 mm diameter near infrared (NIR) enhanced Si APD with QE of 0.38 displayed sensitivities of 23 - 32 photons/bit for a BER of 10-2 at 1064 nm in the absence of background light. Backgrounds of 400 photons per 25 ns slot degraded the sensitivity to approximately 58 photons/slot. Finally a 3 mm diameter NIR enhanced Si APD yielded a sensitivity of approximately 100 photons/bit 1064 nm for BER of 10-2 with no background present.

Paper Details

Date Published: 26 April 2002
PDF: 12 pages
Proc. SPIE 4635, Free-Space Laser Communication Technologies XIV, (26 April 2002); doi: 10.1117/12.464111
Show Author Affiliations
Abhijit Biswas, Jet Propulsion Lab. (United States)
Beckett Madden-Woods, Jet Propulsion Lab. (United States)
Meera Srinivasan, Jet Propulsion Lab. (United States)
Victor Vilnrotter, Jet Propulsion Lab. (United States)
William H. Farr, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 4635:
Free-Space Laser Communication Technologies XIV
G. Stephen Mecherle, Editor(s)

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