APPARATUS FOR REDUCTION OF NONLINEAR SIGNAL DEGRADATION AND OF FADING AT INSIDE OF LONG-DISTANCE OPTICAL TRANSMISSION SYSTEM

摘要

PURPOSE: To reduce non-linear signal deterioration and fading in a long distance optical transmission system. CONSTITUTION: Two optical signals 101, 102 having respectively different wavelength components and almost orthogonal relative polarization components are sent to the same transmission line 105. Two signals to be received on the receiving side end part of the line 105 have almost equal optical power levels and are modulated to carry the same information. Thereby a signal to be transmitted is not almost polarized. Consequently an adverse effect depending upon polarization can be suppressed. In addition, the influence of non-linearity to be increased as a function of a power level can be minimized.