Patent ID: 8896302

Claim:
A method for measuring magnetic induction intensity of a magnetic field using a short cavity fiber laser, comprising the steps of: a) providing the short cavity fiber laser, comprising: a laser diode pumping source; a wavelength division multiplexer connected to the laser diode pumping source; a fiber Bragg grating connected to the wavelength division multiplexer; an active optical fiber connected to the fiber Bragg grating; and a loop mirror connected to the active optical fiber; b) fixing the short cavity fiber laser on a magnetostrictive material; c) disposing the short cavity fiber laser and the magnetostrictive material in the magnetic field to be measured to match a stretching direction of the magnetostrictive material with a direction of the magnetic field to be measured; d) measuring a drift of a longitudinal mode of the short cavity fiber laser; and e) calculating the magnetic induction intensity corresponding to the drift of the longitudinal mode from an equation of: Δ ⁢ ⁢ λ B = 0.78 ⁢ k ⁢ ⁢ λ B k ′ ⁢ H 0 , wherein Δλ B represents the drift of the longitudinal mode, λ B represents the longitudinal mode, H 0 represents the magnetic induction intensity of the magnetic field, k represents the sensitivity coefficient of the magnetostrictive material, and k ′ = E f ⁢ ⁢ 2 ⁢ A f ⁢ ⁢ 2 ⁢ L 1 + E f ⁢ ⁢ 1 ⁢ A f ⁢ ⁢ 1 ⁢ L 2 E f ⁢ ⁢ 2 ⁢ A f ⁢ ⁢ 2 ⁢ L m , wherein E f1 and E f2 represent elastic modulus of the fiber Bragg grating and the active optical fiber respectively, A f1 and A f2 represent the sectional area of the fiber Bragg grating and the active optical fiber respectively, L 1 represents the length of the fiber Bragg grating, L 2 represents the length of the active optical fiber, and L m represents the length of the magnetostrictive material.