▎ 摘　　要

NOVELTY - Gas-sensitive optical fiber sensor comprises a broadband light source (1), a polarizer (2), a test gas chamber (3), a D-type photonic crystal optical fiber (4), a single-mode optical fiber (5), a spectrum analyzer (6) and a computer (7). The D-type photonic crystal optical fiber is located in the test gas chamber. The test gas chamber is provided with an inlet (8) and an outlet (9) for controlling the ethane gas. The D-type photonic crystal optical fiber side polishing surface is coated with tin oxide doped graphene oxide nano-belt film. USE - Gas-sensitive optical fiber sensor for judging an fault degree of a transformer. ADVANTAGE - The sensor realizes refractive index sensing, and has high sensitivity, flexible design, compact structure, strong stability and wide application value. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a gas-sensitive optical fiber sensor and method for judging the degree of transformer fault, which involves: (A) preparing photonic crystal fiber by the stack-drawing technology by polishing in the V-shaped groove and processed into a D-shaped photonic crystal fiber; (B) coating described D-type photonic crystal fiber coated with tin oxide doped graphene oxide nanoribbon film by using the radio frequency magnetron sputtering method; (C) pretreating quartz sleeve and drawing capillary according to the parameters in an ultra-clean environment, and the drawing temperature is 1900-2000 degrees C; and (D) filling the gap with a pure quartz rod, sinter the quartz sleeve and the capillary with an oxyacetylene flame, and use the double-drawing technique on the drawing tower to make a photonic crystal fiber. DESCRIPTION OF DRAWING(S) - The drawing shows schematic view of gas-sensitive optical fiber sensor. Broadband light source (1) Polarizer (2) Test gas chamber (3) D-type photonic crystal optical fiber (4) Single-mode optical fiber (5) Spectrum analyzer (6) Computer (7) Inlet (8) Outlet (9)