Aiming at the problems of low response sensitivity of giant magnetostrictive material-based fiber Bragg grating(GMM-FBG) current sensor and FBG is easy to be disturbed by ambient temperature

a GMM-FBG sensor with special-shaped GMM structure and parallel magnetic loop is designed under prestress.Firstly

the theoretical model of the sensor is constructed

and the response characteristics of the cylindrical GMM rod and the special-shaped GMM rod are compared under prestress by COMSOL simulation

and the structure size of the GMM is optimized according to the gate length of the FBG.Then

the structure of the magnetic ring is analyzed

and the appropriate shape and magnetic circuit spacing are obtained.Finally

the influence of ambient temperature is eliminated by means of difference.The relationship between the difference of the central wavelength of the two FBGs and the measured current is obtained by experiment.The results show that the magnetic flux distribution of the square magnetic ring is more uniform

the sensitivity of the sensing system is 17.13pm/A when the prestress of the special-shaped GMM rod is 30MPa

the magnetic circuit spacing is 60mm

and the input current is 0~100A.