High speed fiber optics data transmission system development has occurred mostly due to low loss fused silica glass fibers, optical amplifiers, as well as wavelength division multiplexing systems. However, simultaneous multi-channel transmission and optical signal amplification increases the power of the optical signal to be transmitted. Thus, optical fiber nonlinear properties start to emerge more pronounced, that causes a variety of undesirable signal distortions and impairs the transmission system performance. In addition, the fiber non-linearity is associated not only with the distorting influence to the signal transmission, but also with new opportunities in optical signal processing. Therefore, it is important to take into account not only the optical fiber attenuation and dispersion, but also parameter, that characterizes its non-linearity – nonlinear coefficient. Doctoral thesis covers the accomplished study about the telecommunications optical fiber effective area and nonlinear coefficient evaluation methods, as well as fiber nonlinearity is successfully implemented in the application of optical signal regeneration completely in the optical domain. As a result, the thesis summarizes the completed research results, that makes it possible to perform an assessment of fused silica glass optical fiber nonlinearity and its application possibilities to establish the optical regenerators.