Abstract
In this article, we research the physic and mathematical model of a digital coherent optical spectrum analyzer, which made it possible to obtain an analytical expression for calculating the spatial spectral resolution of the spectrum analyzer depending on the parameters of the spatial light modulator, the Fourier lens, and the matrix detector. To determine the spatial resolution of the aberrational Fourier lens, it is proposed to use a criterion similar to the Rayleigh criterion. Obtained the formula for determining the dependence of the spectral resolution of the processor on the aberration parameter of the Fourier lens, the research of which showed that for small pixel sizes of the detectors the resolution is determined by the size of the modulator matrix, and for large pixels by the pixel size.