MEASUREMENT OF THE VEER AND ROTATION OF AN OPTICAL FIBRE USING A BRAGG GRATING

There is presented a method for measuring the angle of rotation and twisting using a periodic incline of tilted fibre Bragg grating (TFBG) with an inclination angle of 6 degrees recorded in a single-mode optical fibre. It was shown that when the sensor rotates through 180 degrees, the transmittance changes from 0.5 to 0.84 at a wavelength of 1541.2 nm. As a result of measurements, it was found that the highest sensitivity can be obtained for angles from 30 to 70 degrees concerning the necessary orientation. A change in the transmission spectrum occurs for cladding modes that change their intensity with a difference in the polarization of light propagation through the grating. The same design can be used to measure the angle of rotation. The possibility of obtaining a TFBG rotary device at an edge of 200 degrees with a length of more than 10 mm has been proved. It allows controlling both the angle of rotation and the twisting of the optical fibre using the manufactured TFBG.