Short-gauge fiber grating displacement sensor

The utility model belongs to the technical field of structural safety monitoring, and relates to a short-gauge fiber grating displacement sensor. Comprising main components such as an outer sliding block, an extension spring, a displacement sensing piece, a fiber grating, a push rod, a compression spring and an inner sliding block. During working, the movement of the outer sliding block drives the change of the tensile force of the extension spring, so that the displacement sensing piece generates cooperative deformation, the fiber bragg grating generates corresponding deformation accordingly, and the actual displacement of a detected object is converted by detecting the offset of the resonant wavelength of the fiber bragg grating. The innovation of the utility model lies in that the measured direction and the stress deformation direction of the fiber bragg grating are not in the same straight line but are vertically distributed at 90 degrees, and displacement conversion is carried out through a steering stru