4 b/s/Hz spectrally efficient transmission for an 8 channel CSRZ modulated DWDM system

The core of the global telecommunication network consists of wavelength division multiplexed (WDM) optical transmission systems. WDM is the technology of choice as it allows for a high spectral efficiency. We propose an effective way to counter the nonlinearities like Four Wave Mixing and Cross Phase Modulation to achieve the spectral efficiency of 4 b/s/Hz using CSRZ modulation format. We use the concept of non-uniform channel spacing and non-uniform power assignment between adjacent channels of the WDM system. We have simulated an 8 channel DWDM lightwave system with bit rate of 100 Gb/s and channel spacing of 25 GHz.