
possibilities for concatenating the þD/–D fibers, which we study next as a
function of the amplifier configuration [47].
We compare by using numerical simulations four fiber/amplifier configura-
tions, as schematized in Figure 14.17. Configuration (a) is the most standard
configuration involving EDFA repeaters. Configuration (b) is the replica of con-
figuration (a) but combines a Raman preampli fier and an EDFA in the repeaters,
whereas configuration (c) uses only Raman repeaters. Finally, configuration
(d) differs from configuration (c) by the fact the transmission fiber consists of
three fiber sections þD/–D/ þD instead of two.
We compare the relat ...