Effects of fiber nonlinearity and polarization mode dispersion on long-distance transmission systems with optical in-line amplifiers

摘要

Recent developments in Er-doped optical amplifiers enable very-long transmission systems to be created without regenerating repeaters. However, in very long fibers, nonlinear effects, especially four-wave mixing(FWM) and self-phase modulation(SPM), and polarization mode dispersion(PMD) become important and must be taken into account. This is because they can seriously degrade the transmission performance. In this paper, we demonstrate the effects due to nonlinearity and PMD, quantitatively. Countermeasures to these effects and the key points in measuring fiber and system parameters are also discussed.