ANALYSIS OF EFFECTIVE POWER BUDGET IN OPTICAL BUS AND STAR NETWORKS USING ERBIUM-DOPED FIBER AMPLIFIERS

Passive optical bus networks have been considered to be inferior to st ar networks because of their poorer power loss characteristics, which means that they can support fewer stations than a star. This paper stu dies the use of erbium-doped fiber optical amplifiers (EDFAs) in bus a nd star networks. We determine the number of stations that can be supp orted with and without amplifiers in a single folded bus, a double bus , and a star. For a typical case, when only one station on the bus is allowed to transmit at a time, as is the case in a time-division multi plexed network, the number of stations that can be supported with ampl ifiers is of the order of several thousands. However, this number drop s to less than a thousand when all stations are allowed to transmit si multaneously on different channels in a wavelength-division multiplexe d network, because of amplifier gain saturation. In the former case, t he bus has the potential to outperform the star, but in the latter cas e, the star topology is still better