Fig. 1. The fabricated fiber-optic magnetic field sensor created by embedding a heterodyning fiber laser into an epoxy resin-bonded magnetostrictive composite material with Terfenol-D particles incorporated.

Fig. 2. The experimental setup for the magnetic field measurement. ISO: isolator; WDM: wavelength division multiplexer; PC: polarization controller; PD: photo detector.

Fig. 3. Measured beat frequency when a 3600 Gs magnetic field is applied to the fabricated fiber-optic magnetic field sensor.

Fig. 4. The measure beat frequency shift of the fiber laser for various applied magnetic field magnitudes. A fitted curve for the measured results is also plotted as the solid line.

Fig. 5. The setup to measure the directivity of the proposed fiber-optic magnetic field sensor. The direction of the measured magnetic field is fixed, but the direction of the sensor is rotated to different angles.

Fig. 6. The beat frequency shift of the fiber laser for various angles between the sensor and magnetic field direction with a 3600 Gs magnetic field applied. A calculated curve is also plotted as the solid line.