The present application provides a fingerprint sensor. The fingerprint sensor includes an array of a plurality of optical fibers. Each of the plurality of optical fibers has a first end and second end opposite to the first end. Each of the plurality of optical fibers is configured to allow an incident light to enter into the second end and an exit light to exit from the second end. Each of the plurality of optical fibers includes a fiber core; a fiber Bragg grating in the fiber core; and a reflective film on the first end.