Degradations in practical high speed transmission systems using distributed feedback lasers

It was recently discovered that the performance of practical gigabit-per-second transmission systems using distributed feedback (DFB) lasers can be severely degraded by two new kinds of signal-dependent noises: the interferometric noise arising from multiple reflections at the connectors and splices, and mode-partition noise of the main mode and the dominant side-modes. The authors review the origin of these two kinds of noise and their impact on gigabit-per-second transmission systems, and suggest ways to minimize the amount of system degradation. They show that the return losses of all connectors and splices must be minimized, and that the DFB lasers must be carefully screened, in order to ensure reliable operation of practical gigabit-per-second transmission systems.<>