Non-Linear Impairment Compensation Using Correlated Backward Propagation

Abstract: The main distinction of a fiber optical link is that it modulates the light as a form of energy and use the optical fiber as a medium of propagation from source to destination. We can utilize light as a best source for communication if we can use the higher order modulation formats to increase the spectral efficiency and allow it to propagate over long distance fiber with minimal degradation. So in the Optical Fiber Communication chapter we have investigated the behaviour of light under certain condition as it passes through the optical fiber. Moreover in the past decades various algorithms for compensating optical fiber impairment have been playing a vital role in digital signal processing technologies causing a profound change in telecommunication revolution as bit rate gets higher from 112 Gbits/s to 224 Gbits/s. To compensate the deterministic nonlinear impairments we have also investigated the performance of Digital Backward Propagation (BP) and Correlated Backward Propagation (CBP) by digitally back propagating the received signal through a virtual fiber. The main objective of our study is to conclude the influence of various parameter which will provide a clear guideline for implementation of both algorithms in future real time digital signal processing. In our study we have used dual polarization 4 QAM transmitter signal through standard mode fiber (SSMF) of length 300 to 1200 km. We have used 5, 10 and 20 spans of 60 km standard signal mode fiber (SSMF) respectively with nonlinearity and dispersion. The attenuation of each span was compensated by an Erbium Doped Fiber Amplifier (EDFA). We have studied that the CBP performance is enhanced drastically compared to conventional BP if the parameters are optimized. Modeling and result has been sustained by the numerical simulation in Optisystem and Matlab.