▎ 摘　　要

NOVELTY - The invention claims a reflective optical fibre humidity sensor based on PVA and graphene, wherein the circulator has three interface ends, comprising a feedback end connected with the broadband light source, an outlet end connected with the sensing head, and a feedback end connected with the spectrum analyzer; characterized in that: the sensing head comprises a single-mode optical fibre and a core-free optical fibre; the right end of the single-mode optical fibre is connected with the left end of the coreless optical fibre; the right end of the non-core optical fibre is designed with an inclined end face with an inclined angle of 10 degrees; the inclined end face is provided with a composite film; The composite film is made of PVA and graphene composite material. The invention has reasonable structure design; the sensing head uses reflection type structure; it is convenient to measure; it has high sensitivity, simple manufacturing, small volume, convenient use and good practicability. and the sensing head does not relate to dangerous drugs, and it is safe to use.