Optical electrical current sensor utilizing a graphene-microfiber-integrated coil resonator

A graphene-based electrical current sensor is proposed utilizing a microfiber coil resonator. Monolayer graphene sheet with a large sheet resistance is transferred onto the surface of a glass capillary rod. A microfiber is spirally wrapped around the graphene sheet to form a coil resonator. Heat generated from electrical current shifts the resonant wavelength because of the thermal effect in the microfiber resonator. The sensor exhibits a very good performance with a high sensitivity of 67.297 μm/A2, which is two orders of magnitude higher than that reported earlier. Our results show that microfiber-graphene-integrated devices have great potential for miniature and highly sensitive fiber sensors for monitoring electrical current.