A differential Coherent Optical Time Domain Reflectometry (COTDR) distributed acoustic sensing device based on a heterogeneous double-sideband chirped pulse. The device comprises a light source (1), a 1*2 polarization-maintaining fiber coupler (2), a dual Mach-Zehnder electro-optical modulator (3), an arbitrary waveform generator (4), a first reactatron (5), a second reactatron (6), an electro-optical modulator bias control board (7), a 1*2 fiber coupler (8), an erbium-doped fiber amplifier (9), a fiber filter (10), a fiber circulator (11), a sensing fiber (12), a three-ring polarization controller (13), a 2*2 fiber coupler (14), a balanced photoelectric detector (15), a data acquisition card (16), and a processing unit (17). Also disclosed is a differential COTDR distributed acoustic sensing method based on the heterogeneous double-sideband chirped pulse. According to the device and method, heterogeneous double-sideband chirped pulse modulation is combined with a COTDR technology, the sensitivity of acoustic wave signals to be detected is doubled, suppression of common-mode noise is achieved, and the signal-to-noise ratio is greatly improved.
DIFFERENTIAL COTDR DISTRIBUTED ACOUSTIC SENSING DEVICE AND METHOD BASED ON HETEROGENEOUS DOUBLE-SIDEBAND CHIRPED PULSE