Horohorov

The aim of this study is to determine optimal parameters of uniform and          non-uniform fiber Bragg gratings in order to achieve maximum of the reflection spectra for a fixed wavelength. It is developed a method for calculating the non-uniform fiber Bragg and written a program in Matlab for analyzing fiber Bragg grating by author. It is shown that in the case if it is used Gauss non-uniform fiber gratings or Hyperbolic secant (sech) non-uniform fiber gratings the amplitudes of side bands significantly decrease that is the evidence of a qualitative  improvement in the parameters of the reflected spectra compared with non-uniform fiber Bragg grating with a rectangular envelope of the refractive index profile.

The authors proposes an analytical and optimization method of aberration synthesis in optical system to allow automated analysis of lenses with fifth-order aberrations. The method is based on expansion of lateral aberration into Chebyshev polynomials, followed by minimization of the expansion coefficients.

The author analyzed the process of optical soliton’s occurrence due to the balance between two competing physical processes; they are dispersion spreading of light pulse and phase self-modulation (PSM) which occurred due to the non-linearity of optical signal’s propagation medium (Kerr effect). The method of compensation of the optical signal’s chromatic dispersion in the fiber was proposed. Analytical expressions of mathematical expectation and dispersion of the repetition period of solitons and the value of the solution signal were obtained from random time of the pulse’s arrival to detector. The obtained data must be taken into consideration when calculating signal-to-noise ratio in soliton of the fiber-optic transmission system (FOTS). The analytical expressions of time response, amplitude-frequency characteristics (AFC) and phase-frequency characteristics (PFC) were obtained for different input signals: for Dirac delta function and for Gaussian. These characteristics were conditioned by Rayleigh backscattering.