Simultaneous acoustic and magnetic measurement using cascaded fibre Bragg grating

A fibre-optic sensor is proposed to conduct acoustic and magnetic measurements simultaneously. The sensor consists of two cascaded fibre Bragg gratings (FBGs), one of which is inserted into a magnetic extension bulk (TbDyFe (Terfenol-D)). This is to conduct the magnetic measurements while the other conducts the acoustic measurements. In this research, some pre-processing has been used to improve the sensitivities of the sensor. Side-band filtering technology-based intensity interrogation is used for the acoustic detection, and wavelength interrogation is used for the magnetic measurement. The results of the present study indicate that the sensor is able to measure acoustic and magnetic simultaneously within a considerable range.