What is the actual capacity of single-mode fibers in amplified lightwave systems?

Abstract
The combination of amplifier noise and optical nonlinearities limits the maximum capacity of single-mode fibers in amplified lightwave systems. Using fundamental considerations, it is shown that the capacity of single-mode fibers in transcontinental amplified lightwave systems is not terabits/second but less than 100 Gb/s with ideal amplifiers, and significantly less in realistic systems.