Effects of chromatic dispersion and self - phase modulation on optical transmission system

Abstract

At high bit rate chromatic dispersion (CD) is a dominant factor that limits the transmission distance. Moreover, in long distance transmission high input power is required to overcome the loss encountered by fiber attenuation, but self-phase modulation (SPM) is a nonlinear effect that limits the allowable input power and system capacity by generating new frequency components. The combined effect of SPM and CD limits the operating bit rate and transmission distance drastically. In this thesis, an analysis is carried out to find an expression for pulse broadening factor by solving the nonlinear Schrodinger equation (NLSE) considering the effects of' SPM and CD. The validity of the proposed expression is determined by comparing the numerical results with the results provided by the expression. The results are evaluated at different bit rates (10 Gbps and 40 Gbps), different input power (30 mW, 60 mW, and 90 mW) and varying transmission distance for two different types of fiber standard single mode fibers (SSMF) and large effective area fibers (LEAF). The derived expression shows good agreement with numerical results.