Nonlinear effects in Fiber Optic Communication

The need for high data rates and bandwidth has resulted in communicating via optical fibers. A couple of undesirable nonlinear effects in the optical fiber medium has become a factor of noticeable concern at high power levels. These fiber nonlinearities introduce errors into the transmitted data stream transported over optical fiber communication systems. Information carried by a light signal in a Wavelength Division Multiplexing (WDM) system is subject to degradation due to nonlinear effects in the fiber. Under the influence of intense electromagnetic field, any dielectric medium shows nonlinear effects. Likewise, in optical fibers the dielectric medium like silica responds nonlinearly to light in the presence of intense electromagnetic fields. The change in the refractive index of the medium of the optical fibers with high intensity produces nonlinear effects which known as Kerr effect. In this paper, three nonlinear effects such as Self-Phase Modulation (SPM), Cross-Phase Modulation (XPM) and Four-Wave Mixing (FWM) are studied when the light signal passes through both single mode and nonlinear optical fibers. A comparison of SPM, XPM and FWM is carried out through simulation studies by analysing the effects of different parameters like link length, transmitting power, chirp factor and channel spacing on the optical spectra at the receiving end of both types of fibers