▎ 摘　　要

NOVELTY - The biosensor has an optical fiber having an end surface and an outer surface which are coated with a conductive material. A channel is arranged on the end surface and the outer surface. The conductive material is divided into two electrodes including a drain and a source of a FET. A graphene film is arranged on an end face of an optical fiber and respectively connected to the drain and the source. A surface of the graphene film is fixed with a single-stranded DNA as a probe chain. An end of the probe chain modifies the fluorescent dye. USE - Optical fiber FET biosensor used in biological testing device (claimed). ADVANTAGE - The detection accuracy and reliability of the biosensor are improved. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method of preparing optical fiber FET biosensor; (2) a biological testing device; and (3) a detection method of the biometric detection device. DESCRIPTION OF DRAWING(S) - The drawing shows a flow diagram illustrating the method for preparing the optical fiber FET biosensor. (Drawing includes non-English language text)