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Proceedings Paper

Modified PN code laser modulation technique for laser measurements
Author(s): Xiaoli Sun; James B. Abshire
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Paper Abstract

Pseudo-noise (PN) modulation techniques have been used to modulate lasers for time of flight measurements and for profiling atmospheric backscatter. Compared to mono-pulse techniques, PN code modulation allows timing and backscatter measurements to be made with much lower laser peak powers and higher duty cycles. We have developed a new modified version of PN code modulation for laser measurements in which the laser pulse width and position may also be varied within the PN code bit interval. These allow more degrees of freedom for optimizing laser measurements. We have demonstrated these in laboratory measurements using a 974 nm laser diode, return to zero (RZ) PN code modulation at various laser pulse duty cycles, and a photon counting receiver. The results show significant improvements in the receiver signal to noise ratio, sensitivity, and ranging precision for the lower duty cycle RZ PN codes.

Paper Details

Date Published: 24 February 2009
PDF: 8 pages
Proc. SPIE 7199, Free-Space Laser Communication Technologies XXI, 71990P (24 February 2009); doi: 10.1117/12.817254
Show Author Affiliations
Xiaoli Sun, NASA Goddard Space Flight Ctr. (United States)
James B. Abshire, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 7199:
Free-Space Laser Communication Technologies XXI
Hamid Hemmati, Editor(s)

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