Investigation of Single 160 Gbit/s PM-QPSK Channel

The explosive increase in the number of Internet users boost the demand for high speed data capacity in Access networks, Metro networks and especially in Core networks. The systems with 10 Gbit/s and 40 Gbit/s have already seen much of the research and now the focus has shifted to even higher datarates of 100 Gbit/s and 160 Gbit/s per wavelength. Since optical data transmission with conventional modulation formats based on on-off-keying (OOK) at such high datarates is adversely affected by linear and non-linear effects, it’s important to look at other modulation formats offering resistance to these effects. Polarization Multiplexing Quadrature Phase Shift Keying PM-QPSK is one such modulation format which must be studied at ultra-high data rate of 160 Gbit/s. In this paper the performance of a single channel PM-QPSK having datarate of 160 Gbit/s has been investigated with coherent detection of the optical signal along with the digital signal processing for dispersion compensation in a scenario of rapid increase in demand for datarate. Here the study has been carried out on 900kms of uncompensated SSMF and NZDSF with the different launch powers and also OSNR requirement for the system in back to back configuration has been derived. Also an increase in optical reach has been achieved through two methods first being Distributed Raman Amplification (DRA) and pump power has been optimized for the same and second by using shorter fiber spans with EDFA amplification only.