▎ 摘　　要

NOVELTY - Optical fiber grating sensor, comprises a broadband light source (9), connected to one end of a long-period optical fibre grating (10) through the coupling optical fibre. A spectrum analyzer (11) is connected to the other end of the long-period optical fibre grating through coupling optical fibre. The grating area of the long-period optical fibre grating is formed with a coating layer of the polydopamine. The polydopamine-graphene oxide mixed dispersion is composed of a polydopamine dispersion and graphene oxide dispersion. USE - The sensor is useful for detecting heavy metal ion (claimed). ADVANTAGE - The sensor has simple structure, convenient control, reasonable design, low cost and easy popularization, and strong practicability. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: preparation method of optical fiber grating sensor; and detecting heavy metal ion. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an optical fiber grating sensor. 9Broadband light source 10Long period fibre grating 11Spectrum analyzer 13Ion detecting pool