▎ 摘　　要

NOVELTY - The sensor has a photonic crystal fiber whose two ends are respectively connected with two single-mode optical fibers. A waist-expanded fiber coarse taper part is formed at two coupling points of each single-mode optical fiber. A surface of the photonic crystal fiber is formed with a graphene layer i.e. single-layer graphene, where distance between the coupling points is about 3.9 to 4.1 cm, length of the waist-expanded fiber coarse taper part is about 395 to 405 and thickness of the graphene layer is 0.33 to 0.35 nm. USE - Graphite fiber sensor for a refractive index detecting system (claimed). ADVANTAGE - The sensor can detect hydrogen sulfide gas and sucrose gas concentration in an easy manner. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for manufacturing a graphene optical fiber sensor. DESCRIPTION OF DRAWING(S) - The drawing shows a front view of a graphite fiber sensor.