Fig. 1. Schematics of EFBG-FP magnetic field sensing probe. (a) 3D schematic diagram; (b) zoom-in view of EFBG-FP cavity; (c) physical image of sensing probe

Fig. 2. Schematic of magnetic field sensing system based on EFBG-FP filter and OEO

Fig. 3. Working principle of OEO based on EFBG-FP filter. (a) Principle of EFBG-FP filter; (b) frequency response of MPF

Fig. 4. Reflection and transmission spectra of EFBG-FP filter

Fig. 5. Electrical spectrum of the generated microwave signal by OEO (span is 4 MHz; resolution bandwidth is 20 kHz)

Fig. 6. Microwave signals under different magnetic fields (span is 8 GHz; resolution bandwidth is 3 MHz)

Fig. 7. Relationship between magnetic field and the frequency of microwave signal