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Proceedings Paper

Examining cable plant bandwidth for FDDI
Author(s): James E. Hayes
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Paper Abstract

Networks designed around the ANSI X3T9. 5 standard called Fiber Distributed Data Interface (FDDI) are limited in distance by the bandwidth not the attenuation of the fiber optic cable. The magnitude of this limitation is defined and potential options in sources and fibers are examined. Since FDDI is limited in distance by the bandwidth of the cable plant not the attenuation many end users have put a bandwidth specification in their fiber optic cable purchase specifications. Some have even specified testing for bandwidth. This has caused much controversy between vendors installers and users. As a test equipment vendor we have " refereed" quite a few of these already and we have found that more myths are believed than realities are understood. What Limits Fiber Bandwidth? Two things limit fiber bandwidth: modal dispersion and chromatic dispersion. Modal dispersion is caused by the fact that the graded index profile of the fiber isn''t perfect so all modes do not have exactly the same transit time through the fiber. Chromatic dispersion is caused by the fact that the velocity of light in the fiber is dependent on the wavelength of the fiber. Fibers are designed for a zero dispersion wavelength light of any other wavelength will have some dispersion. Sources of wide spectral width like LEDs will suffer from more dispersion than narrow spectral width sources like laser diodes. In most circumstances one can

Paper Details

Date Published: 1 February 1991
PDF: 5 pages
Proc. SPIE 1364, FDDI, Campus-Wide, and Metropolitan Area Networks, (1 February 1991); doi: 10.1117/12.24618
Show Author Affiliations
James E. Hayes, Fotec, Inc. (United States)


Published in SPIE Proceedings Vol. 1364:
FDDI, Campus-Wide, and Metropolitan Area Networks
Kadiresan Annamalai; Stewart K. Cudworth; Allen B. Kasiewicz, Editor(s)

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