Simultaneous measurement of both magnetic field strength and temperature with a microfiber coupler based fiber laser sensor
In this paper we propose and investigate a novel magnetic field sensor based of a ring erbium-doped fiber laser combined with a fiber Bragg grating and a Sagnac loop containing a microfiber coupler and magnetic fluid. In addition to the magnetic field sensing capability, the proposed structure can simultaneously provide temperature information. Thanks to the dual-ring structure of the MFC-Sagnac loop and the FBG-assisted resonant cavity, the output has two distinct laser peaks. Experimentally demonstrated magnetic field sensitivity of one of the laser peaks is 15 pm/mT in the magnetic field range from 0 to 100 mT. The spectral position of the second laser peak is independent on the magnetic field but shifts towards long wavelengths with a sensitivity of 13 pm/°C.