The present application relates to the technical field of
optical sensing, and more particularly to a displacement
system based on sausage cavity and a displacement sensing method thereof, the
system comprising a computer, a
laser, a
polarization controller, a displacement sensing microcavity, a
fiber waveguide, a
photodetector and a displacement device, the displacement sensing microcavity comprising a first converging section, a straight section and a second converging section, the large-
diameter ends of the first and second converging sections being connected to the two ends of the straight section respectively. The method comprises: starting the displacement device to cause
relative displacement between the displacement sensing microcavity and the
fiber waveguide; when the displacement sensing microcavity is displaced n times, n corresponding
resonance spectra are obtained at the output end of the
fiber waveguide; and the obtained
resonance spectrum data is input into the computer, which monitors the displacement of the displacement sensing microcavity by using the
transmittance change of the
resonance mode, thereby realizing displacement sensing based on the displacement sensing microcavity. The present application is convenient to use and can realize high-precision displacement measurement.