The invention relates to a high-precision wide-range low-coherent interference shift
demodulation device, which comprises a
light source, an
optical circulator, a self-focusing collimation lens, a fixed reflecting mirror, an
optical fiber splicer, a beam
extender lens, a
polarizer, a birefringent optical wedge, a stair-shaped birefringent phase shifter, an analyzer, a
planar array camera and a
processing unit. A
demodulation method comprises the following steps: dividing the light emitted from the
light source into two parts after the light passes through the
optical circulator and reaches the self-focusing collimation lens at the sensing side, wherein one part is directly reflected and the other part is reflected after entering the reflecting mirror fixed on an object to be detected, and the two parts of reflection light have an
optical path difference (OPD); guiding the two parts of reflection light to pass through the
optical circulator again so as to reach the
optical fiber splicer and then reach the birefringent optical wedge and the stair-shaped birefringent phase shifter through the beam
extender lens and
polarizer; realizing the wide-range
optical path difference (OPD) scanning under the combined action of the birefringent optical wedge and the stair-shaped birefringent phase shifter; generating an interference fringe behind the analyzer; receiving the interference fringe by using the
planar array camera; and detecting the shift information through digital
processing by a computer or an
embedded system.