Distributed Acoustic (DAS)

DAS measurement process: the laser emits light pulses along the fiber, and some light interferes with the incident light in the form of backscattering in the pulse. After the interference light is reflected back, the backscattered interference light returns to the signal processing device, and the vibration acoustic signal along the fiber is brought to the signal processing device. Since the speed of light remains constant, a measurement of the acoustic vibration per meter of fiber can be obtained.