Backscatter-based distributed fiber-optic vibration system

The traditional backscatter-base distributed fiber-optic vibration sensing technology (PDVS), as shown in chart 1, comprises a pulse light source 1; the traditional scheme only has one sensing optic cable (as shown in chart 1) and the interference actually occurs in the sensing optic cable. A backscatter-based distributed fiber-optic vibration sensing system comprises a light path system and a data processing system, wherein the light path system comprises a pulse light source, one end of which is connected with one end of a 2*2 coupler; the 2*2 coupler is connected with a sensing optic cableand a reference optic cable. According to the invention, the interference is transferred from the sensing optic cable to the coupler so as to limit the optic path difference of an interference signalin the technological error range of the coupler and reduce the requirement of the system for the line width of the light source.