Theoretical and experimental investigation of low-noise optoelectronic system configurations for low-coherent optical signal detection

In low-coherent measurement techniques two kinds of optical signal processing can be used -spectral and temporal. When the temporal signal processing is used, the most critical problem is to identify the position of the central fringe in the interference fringe pattern. It is so important because this position corresponds to the zero of optical path difference and gives information about a measurand. Therefore, it is necessary to use the low-noise optical signal detection set-up in the low-coherent measurement systems. One of the most effective methods of noise-reduction in low-coherent system is using detection system in balanced configuration. In this article, authors present the designed low-coherent optical signal detection system. This system enables us to perform balanced and un-balanced detection, which allows to compare parameters of both configurations. The authors describe theoretical and experimental investigation of balanced and un-balanced low-coherent optical signal detection system