The invention discloses a high-accuracy remote absolute displacement measurement
system based on
optical fiber composite interference, which belongs to the technical field of optical measurement and is composed of a board band
light source, an
optical fiber isolator, three 3dB couplers, four auto-collimation mirrors, two
optical fiber gratings, four reflectors, two detectors, a
circulator, a one-dimensional translation platform, piezoelectric ceramics, a
feedback control circuit, a
signal generator, a
signal treatment circuit, an analog to digital (A / D) conversion card, a computer and result output. The high-accuracy remote absolute displacement measurement
system uses an optical
fiber interferometer to induce displacement and another optical
fiber interferometer to demodulate displacement to achieve remote measurement. The optical
fiber interferometer for
demodulation works in a low coherence interference state and a high coherence interference state, and amplitude of displacement can be determined by low coherence signals to achieve
absolute measurement. A value of the displacement can be measured by high coherence signals to feed back and control effects of environment interference on the demodulating optical
fiber interferometer, and high-accuracy measurement can be obtained.