Study of Fiber Nonlinearities and Effect of Phase, Input Power and Chirping Factor on Received Power

Abstract

Optical fibers are not only used in telecommunication links but also used in the Internet and local area networks (LAN) to achieve high signaling rates. In this dissertation, fiber nonlinearities have been studied, and analyze the effect of various parameters on the received power. Optical amplifiers like EDFAs simply amplify the optical signal by several orders of magnitude without being limited by electronic speed. Transmission impairments, which are general not significant in a regenerative system, accumulate along the transmission link when amplifiers are used, so that they can not be simply ignored, and this puts a new challenge to transmission design engineers. The nonlinearities in optical fibers fall into two categories. One is stimulated scattering (Raman and Brillouin), and the other is the optical Kerr effect due to changes in the refractive index with optical power. Phase modulation due to intensity dependent refractive index induces various nonlinear effects, namely, selfphase modulation (SPM), cross-phase modulation (CPM), and four-wave mixing (FWM). For an understanding of nonlinear phenomena in optical fibers it is necessary to understand the Nonlinear Schrödinger equation, which describe the propagation of wave in nonlinear medium. It is required to solve the nonlinear Schrödinger equation to understand various impairments occurring during signal transmission. The split-step Fourier method is one of the most popular algorithms because of its good accuracy and relatively modest computing cost. Nonlinear equations are simulates in using split step Fourier transform to study the effect of various parameters.