▎ 摘　　要

NOVELTY - The method involves preparing functional optical fibre grating. The functionalized optical fibre grating is prepared by depositing polydopamine the surface of the optical fibre grating-graphene layer. One end of the functionalized fiber grating prepared is connected with the broadband light source (9). The grating area portion of the fiber grating coated with the polydopamine oxide (12) is placed in the ion detecting pool. The other end of the fiber grating is connected with the high resolution spectrum analyzer (11). The dripped cobalt ion is combined with the poly dopamine-oxidation graphene material coated on the surface of the grating grid area to change the surrounding refractive index to change the action of the light coupling at last. The different concentration is observed by the high resolution spectrum analyzer. The spectrum detection of the cobalt ion is realized. USE - Method for detecting cobalt ion based on functionalized fiber grating used in optical sensing and optical communication field. ADVANTAGE - The device has simple structure, convenient control, reasonable design, low cost and easy popularization, and strong practicability. The method is simple to operate, easy to realize, and the concentration ratio is variable, and has high sensitivity. DESCRIPTION OF DRAWING(S) - The drawing shows a micro-cone long-period optical fiber grating of the coating of the polydopamine graphene, for the cobalt ion water dispersion of the test device system structure. 9Broadband light source 10Long period fibre grating 11Spectrum analyzer 12Polydopamine oxide 13Ion detecting pool