Highly sensitive vector magnetic field sensors based on fiber Mach–Zehnder interferometers

A highly sensitive vector magnetic field sensor based on a fiber Mach–Zehnder interferometer (FMZI) is proposed and demonstrated. The FMZI is composed of a micro-cavity that is fabricated in a single-step laser-induced micro-plasma process with a modest-powered nanosecond fiber laser. Combined with a magnetic fluid, the micro-cavity-based FMZI is constructed to a magnetic field sensor for vectorial sensing. The presented magnetic sensor exhibits a maximal strength sensitivity of 64 nm/mT that is the highest among reported vector magnetic field fiber sensors to date, to the best of our knowledge. • Micro-cavity based fiber Mach–Zehnder interferometer fabricated by one-step ns laser. • The magnetic fluid was combined with fiber Mach–Zehnder interferometer to produce a magnetic field sensor. • Fabricated fiber vector magnetic field sensor with high sensitivity of 64 nm/mT.