
progress for undersea applications, but this situation could change quickly when
the operators are willing to increase the channel rate to 40 Gbit/s over the sub-
marine rout es.
14.4 AMPLIFIER SCHEME AND POWER
MANAGEMENT
14.4.1 Erbium-Doped Fiber Amplifiers (EDFAs)
Erbium-doped fiber amplifiers (EDFAs) have been the one of the key constituents
of optical undersea systems. The progress in terms of noise figure, bandwidth, gain
uniformity vs wavelength, and output power has largely set the pace of the
undersea system performance for more than 10 years. Nevertheless, EDFA tech-
nology seems to have now reached its pinnacle and little improvement is expected ...