Fiber optical systems, which are used today, are realized due to two technologies – one provides a possibility to get a low attenuation SiO2 fiber and another allows for a high-speed optical information transmission (erbium amplifiers, Raman amplifiers, WDM, etc.). Transmission of the optical signals in telecommunication fibers are influenced by nonlinear optical effects (NOE) because small core diameters lead to significant light intensities even at moderate signal powers. NOE and their physical nature, reasons of origination, possibilities of their use in communications and processing of information are considered in this paper.