Noise impact on the process of multimode beam retrieval by the modal decomposition method

Abstract: Today, the development of tools for analyzing the spatio-temporal properties of optical radiation is a hot topic because of the increased interest in multimode optical technologies. The determination of mode composition and of intermode phases of optical beams is particularly important in the context of studies of new nonlinear effects in multimode waveguides. However, the mode decomposition methods being developed have some limitations that affect their accuracy. This paper is devoted to the study of the impact of recording camera noise in the process of mode decomposition of optical radiation by the correlation filtering method. A significant impact of intensity noise on determining the position of the center of correlation response, a key step in mode decomposition. In order to improve the accuracy of the method, it is proposed to use the Jensen-Shannon metric that allows to effectively determine the center of correlation response of noisy signal. The proposed approach is resistant to a noise level of around 7%.

Keywords: mode decomposition, multimode step-index fibers (SIF), spatial light modulator, image noise.