Study of Non-Linear E ects in Fiber Optic Communication and Improved Link Design

Abstract

Fiber optics communication have come a long way since its evolution in 1970. As a result of which communication using optical carriers have became popular to the world. The requirements of data transmission for communication via ber optics is increasing day by day. So data are being sent at high transmission rate as well as over long distance. Thus nonlinear e ects in ber comes into picture. The main objective of this thesis is to study the nonlinear e ects in optical ber when transmission rates are very high and to discuss their e ects on input signal in form of dispersion. The chromatic dispersion leads to broaden the input pulse as a result of which poor BER performance is observed at the receiver. Thus in order to minimize the e ect of chromatic dispersion, dispersion compensation is essential in link desinging and thus improving the BER performance at the receiver. The cause of nonlinear e ects is either due to intensity dependence of refractive index of the medium or due to scattering phenomenon. This thesis describes various types of nonlinear e ects based on Kerr e ect such as self-phase modulation, cross-phase modulation and four-wave mixing. The thesis also discusses the pros and cons of nonlinear dispersion. The nonlinear e ects were simulated with the help of OPTSIM simulation tool and analyzed using the eye pattern method with respect to bit error rate and Q factor.