Magnetostrictive composite–fiber Bragg grating (MC–FBG) magnetic field sensor

We report a magnetostrictive composite–fiber Bragg grating (MC–FBG) magnetic field sensor based on the direct coupling of the magnetostrictive strain in an epoxy-bonded Terfenol-D particle pseudo-1–3 MC actuator with a FBG strain sensor. The MC–FBG sensor exhibits a large and fairly linear quasistatic peak wavelength shift of 0.68 nm under an applied magnetic field of 146 kA/m and a wide extrinsic magneto-optical signal frequency range up to at least 60 kHz. These quasistatic and dynamic characteristics, together with the electromagnetic interference immunity, large-scale multiplexing potential and self-reference capability, enable the application of the MC–FBG sensor in distributed magnetic field sensing over long distances.

► A magnetostrictive composite–fiber Bragg grating (MC–FBG) magnetic field sensor based on the direct coupling of the magnetostrictive strain in an epoxy-bonded Terfenol-D particle pseudo-1–3 MC actuator with a FBG strain sensor has been developed.
► The quasistatic peak wavelength has been found to shift appropriately linear in accordance with the quasistatic magnetostrictive strain characteristics of the MC bar and by as much as 0.68 nm under a relatively small magnetic field of 146 kA/m, giving a high quasistatic peak wavelength shift sensitivity of about 4.66 × 10−3 nm/kA/m and a large quasistatic magnetostrictive strain sensitivity of about 3.4 ppm/kA/m.
► A wide extrinsic magneto-optical signal frequency range in excess of 60 kHz has been demonstrated and found to be almost 60 times larger than state-of-the-art MA–FBG magnetic field sensors based on monolithic Terfenol-D MA as a result of reduced eddy-current losses in the MC.
► These attractive quasistatic and dynamic performances, in conjunction with the alleviated brittleness, weight, shape and cost problems intrinsic in the MA–FBG sensors, make our MC–FBG sensor great promise for long-distance and distributed magnetic field or electric current sensing.