Method for measuring the strain of material using short cavity fiber laser

摘要

A method for measuring the strain of material using a short cavity fiber laser, includes steps of: a) arranging the short cavity fiber laser, which laser comprises sequentially coupled laser diode pumping source, a wavelength division multiplexer, a fiber bragg grating, an active fiber and a loop mirror; b) fixing the short cavity fiber laser on the material whose strain will be measured, and matching the stretching direction of the fiber of the short cavity fiber laser with the direction of the strain produced by the material to be measured; c) measuring the drift amount of longitudinal mode output by the short cavity fiber laser; and d) calculating and obtaining the strain of the material to be measured.

主权项

1. A method for measuring a strain of a material using a short cavity fiber laser, the method comprising steps of:
a) arranging the short cavity fiber laser, wherein the short cavity fiber laser comprises sequentially a coupled laser diode pumping source, a wavelength division multiplexer, a fiber Bragg grating, an active fiber and a loop mirror; b) fixing the short cavity fiber laser on the material whose strain will be measured, and matching the stretching direction of the active fiber of the short cavity fiber laser with the direction of the strain produced by the material to be measured; c) measuring a drift of a longitudinal mode, wherein the drift is outputted by the short cavity fiber laser; and wherein the drift is generated by stretching of the material; and d) calculating and obtaining the strain of the material to be measured according to the drift from an equation of:Δ⁢⁢λBz=2⁢⁢Λ⁡[-neff32⁢Δ⁡(1neff2)]+2⁢⁢neff·ɛzz·L·∂Λ∂L, wherein ΔλBz represents the drift of the longitudinal mode, Λ represents elastic deformation of the fiber under the stress, neff represents the elastic-optic effect of the fiber, Δneff represents the change of the elastic-optic effect of the fiber, εzz is longitudinal strain, and L represents the longitudinal expansion amount of the fiber.