Polymer Optical Fiber-based Magnetic Sensor Based on Magneto-optical Effect

A magnetic sensor comprising two polymer optical fibers (POFs) and a capillary tube filled with a solution of magnetic microspheres is presented. In the proposed device, the ray path through the capillary tube changes as a result of the variation in microsphere distribution caused by the presence of a magnetic field. The corresponding change in the voltage output signal of the avalanche photodiode (APD) is then used to derive the intensity of the magnetic field. Experimental results show that the proposed sensor has a sensitivity of 6.2 mV/G for magnetic field intensities in the range of 30-100 G. From the experimental results, an empirical expression is formulated to relate the magnetic field intensity with the output voltage ratio. The magnetic field intensities predicted using this formulation deviate from the measured values by less than 1%.