▎ 摘　　要

NOVELTY - Ultra-sensitive gas sensor based on graphene D-shaped optical fiber comprises D-shaped optical fiber and gold-graphene-gold hetero-junction structure film is intermediate graphene thin film and two ends of gold films are contacted with each other. The polishing surface area of D-shaped optical fiber comprises middle flat surface area and two ends of bevel surface areas. The length of polishing surface area is 3-8 mu m, where length of flat surface area accounts 70%-80% of length of polishing surface. The length of two ends of bevel surface area is same. The polishing depth is 1-5 mu m from polishing surface to fiber core is made of single-mode fiber with core diameter of 8 mu m and outer cladding layer diameter of 125 mu m. The graphene film covers flat surface area of polishing surface area of D-shaped optical fiber and length of polishing surface area greater than length of graphene film greater than or equal to length of flat surface area of polishing surface. The thickness of gold film is greater than 20 nm. USE - Used as ultra-sensitive gas sensor based on graphene D-shaped optical fiber. ADVANTAGE - The sensor: enhances the interaction between the input optical signal and external sensing molecules; has small volume and simple structure; sensitivity reaches single molecular weight level; adopts full-fiber structure; conveniently access optical fiber sensing and communication network; and realizes fast real-time monitoring. DESCRIPTION OF DRAWING(S) - The drawing shows a three-dimensional structure of the ultra-sensitive gas sensor based on graphene D-shaped optical fiber.