DEVICE FOR INCREASING THE MEASURING ACCURACY OF A FIBRE GRATING SENSOR SYSTEM

摘要

The invention relates to a device for increasing the measuring accuracy of a fibre grating sensor systems. The aim of said invention is to develop a device which, when used with usual fibre grating sensor systems provided with Bragg gratings and usual polychromators with desired depolarisation and formation, in particular, of Gaussian light beams injected by a fibre grating sensor system, requires a minimum number of optical and adjustment elements and which is mechanically robust and operationally stable, wherein repeatability errors of Bragg wavelengths determination is less than 1 pm. For this purpose, a digital aperture and/or core diameter (d13) of gradient index fibres (13) are always equal to or less than the digital apertures and core diameters (d12) of step index fibres (12). Between the opposite front surfaces (111; 121) of monomode fibres (11) on an input side and the step index fibres (12), the transition (Y-Y) is selected such that the front surfaces (111; 121) of two optical fibres (11, 12) form therebetween an angle a ranging from 6° to 20° and/or the fibre axes in the coupling area of said optical fibres (11, 12) are acentrically oriented.