Upstream dispersion management supporting 100 km differential reach in TWDM-PON

An optical dispersion compensator (ODC) with negative dispersion value in optical line terminal (OLT) is proposed to manage the chromatic dispersion of 10 Gb/s upstream directly-modulated signals from users with 100 km differential distances, achieving a maximal 51.9 dB loss budget thanks to the positive chirp of the directly-modulated signals and the characteristics of access networks that lower loss budget is required for the users at shorter transmission distance. The optimal dispersion value of the ODC is determined by the maximal distance of the users and the objective is to guarantee the loss budget monotonically improved with the increase of reach, therefore supporting differential reach. Experimental results show that it is a potential solution for practical implementation of long-reach and high splitting-ratio time and wavelength division multiplexed passive optical network (TWDM-PON).