A fiber Bragg grating current sensor with temperature compensation

A novel fiber Bragg grating (FBG) current sensor with temperature compensation has been proposed. The fiber Bragg grating is glued on the surface of an isosceles triangle cantilever beam,which has a step thickness along the beam axis. Due to the electromagnetic force created by a solenoid and a permanent magnet mounted on the top of the beam,a step strain is applied on the fiber Bragg grating. The change of the electric current in the solenoid makes the spectrum of the fiber Bragg grating split. By monitoring the shift difference of the two split center wavelengths,which is related to the electric current in the solenoid,a current sensor with temperature compensation is obtained. The test range of 0-400 mA is achieved. The experimental results also show that the relationship between the shift difference of the two split center wavelengths of the FBG and the electric current has a linearity of 0.9937,and the sensitivity is about 2.64 nm/A; the test results are independent of the temperature,so the cross sensitive problem is solved.