In this article the author presents improved techniques of signal processing used in low-coherent measurement systems. The author proposes to utilize the synthesized sources in the system with the temporal signal processing. It will be shown that the exploit of such a source can substantially reduce the signal-to-noise ratio required to identify the central fringe position. In case of using spectral signal processing, the author proposes to control the position of maximum in the spectral pattern which modifies the phase difference between interfering beams. The results of experimental works will show that described techniques can be an effective method for improving the signal processing in low-coherent measurement systems.
In this paper use of selected optical methods of a hematocrit measurement has been presented. Elaborated methods have numerous advantages: relatively simple configurations, potentially low cost and high resolution. Investigation confirmed their ability to determine the hematocrit value with appropriate measurement accuracy. Furthermore, simultaneous use of complementary optical methods can substantially increase measurement reliability, because low-coherence interferometric measurement is based on physical (mainly optical) properties of the investigated object, while Raman spectroscopy is based on study of its molecular composition.
In this paper low-coherence fibre-optic sensors based on the Fabry-Perot and Michelson interferometer, which were designed and elaborated at our laboratory, are shown. We present results of investigation of the fibre-optic sensors working in both configurations. These results allowed us to compare properties of sensors working in both configurations. The theoretical analysis and experimental results made us possible to select best construction, which was implemented in low-coherence fibre-optic sensors of refractive index.