This paper will describe the physical medium for a fiber optic local area network which utilizes the intrinsically simple, fiber efficient, linear bus topology. The implementation relies on three unique fiber optic components - an active WDM coupler, hard plastic clad silica fiber, and a low loss tap for the HCS fiber. In fiber optics, bus topology has fallen out of favor because of the well known difficulty in tapping fiber, as well as cumulative fiber losses from relatively high loss taps. The existence of a low loss (.05dB) tap which can be installed at arbitrary locations on a fiber (without breaking the fiber), allows reconsideration of -the bus. Another benefit of this tap is that the ratios are tunable between -13dB and -35dB during installation. The active WDM further simplifies the architecture by allowing bidirectional transmission on a single fiber bus; halving the amount of taps, connectors, and fiber that would otherwise be required. Short wavelength emitters and detectors are used in the WDM which enhance reliability and reduce cost. Results from a 30 tap bus will be presented and will include off/on tap ratios, bit error rate tests, power budget considerations and receiver considerations.

Date Published: 14 December 1988
PDF: 9 pages
Proc. SPIE 0991, Fiber Optic Datacom and Computer Networks, (14 December 1988); doi: 10.1117/12.960016

Published in SPIE Proceedings Vol. 0991:
Fiber Optic Datacom and Computer Networks
James E. Hayes; James Pazaris, Editor(s)