Transmission of 16 $\,\times\,$40 Gb/s NRZ-OOK Channels Over 2800-km SSMF Using Asynchronous Phase Modulation

Transmission of 16 nonreturn-to-zero on-off keying channels at 40 Gb/s with 100-GHz spacing is demonstrated over 2800 km. This record transmission distance was made possible by the 2-dB increase in power tolerance obtained when employing the cost-effective asynchronous phase modulation technique.