All-fiber acoustic particle velocity sensor based on graphene-coated four-core fiber

A graphene-coated four-core fiber (FCF)-based acoustic particle velocity (APV) sensor for the detection of acoustic location is proposed and experimentally demonstrated. A graphene film is coated on the cross section of the FCF, which can be heated through a 532-nm laser. Due to the antisymmetric temperature distribution of the graphene induced by the APV, the reflection power of different fiber cores in the FCF is modulated, and the acoustic source direction can also be located based on the vector characteristic of the APV. The experimental results show that the figure-of-eight directional response of the graphene-coated FCF with a directional sensitivity of 0.56 mV/deg is achieved. The all-fiber vector acoustic sensor possesses the potential for applications in structural health monitoring, partial discharges, public security, etc.