The long fiber optic paths to power the thermal field disturbance sensor

The application in polarization sensor systems uses changes in the polarization of light in the optical fiber during temperature changes. The principle of operation consists in the specific propagation of polarized light by special optical fibers, which, thanks to their construction, keep the light in two axes, but change the speed of their propagation and thus the instantaneous state of light polarization. It has been shown that by suitable methods it is possible to transform changes in the polarization of light into changes in its intensity, which can be detected very efficiently and quickly by a photodiode. This method has been practically verified, implemented by fiber components and confirmed as suitable for the implementation of a fiber sensor of thermal field disturbance. However, it turns out that especially in military and biomedical applications it is impossible to place a source of optical radiation close to the measured subject and the sensor must be powered remotely using optical fibers of the order of kilometers. This paper shows the possibility of using long optical paths to power the polarization sensor.