40-Gb/s RZ transmission over transoceanic distance in a dispersion managed standard fiber using a new inline synchronous modulation method

We propose a modified soliton control method for a strongly dispersion managed line, which employs a highly nonlinear fiber in addition to conventional inline synchronous modulation. This method enables us to transmit a 10-Gb/s return-to-zero signal over 20000 km using a dispersion managed line composed of a standard (nondispersion shifted) fiber and dispersion compensation. Optimizing the length of the highly nonlinear fiber greatly increases the power margin of the transmitted optical power.