100-Gb/s optical transport network and beyond employing digital signal processing

We overview the requirements and the enabling technologies for optical transmission systems up to 100 Gb/s and beyond. Polarization- division multiplexed quadrature phase shift keying with digital coherent detection, and fast recovery in optical channel rerouting are key technologies for 100-Gb/s long-haul systems and beyond. We review test results of a realtime 80-channel wavelength-division multiplexing transmission over 420 km of field-installed fiber. Finally, we focus on digital nonlinear compensation and pilot tone phase noise compensation as technologies for systems beyond 100 Gb/s.