Experimental Study of Some Key Issues on Fiber-Optic Interferometric Sensors Detecting Weak Magnetic Field

This paper presents some key issues in fiber-optic interferometric magnetic field sensors. Practically applicable methods to design and implement fiber-optic Michelson interferometer and transducers are described with experimental verifications. Detection scheme of traditional hardware demodulation is improved, and a new software demodulation method is addressed. Transducers were implemented by using the proposed methods and the performance was tested. The results show significant performance improvement. The minimum detectable magnetic field using hardware demodulation scheme is about 0.10 $~{\rm nT}/{\rm Hz}^{1/2}$ at 1 Hz without any mumetal shield in the laboratory environment.