▎ 摘　　要

NOVELTY - The utility model claims an underground pressure alarm device, comprising a light source, an optical fibre coupler, a graphene optical fibre pressure sensor, a photoelectric conversion circuit, an A/D conversion circuit and an alarm module, wherein the light source, graphene optical fibre pressure sensor and photoelectric conversion circuit are connected through the optical fibre coupler; the graphene optical fibre pressure sensor comprises a single-mode optical fibre with one end provided with a concave cavity; the end face is provided with a layer of graphene film sealing cavity to form an F-P cavity; the light signal emitted by the light source is transmitted through the optical fibre; the optical fibre coupler is transmitted to the graphene optical fibre pressure sensor; the optical signal modulated by the F-P cavity is received by the photoelectric conversion circuit by the optical fibre coupler; the photoelectric conversion circuit converts the modulated optical signal into electric signal and amplifies; outputting the electric signal by the binary digital signal through the A/D conversion circuit; comparing the alarm module with the set threshold value; alarming when the threshold value exceeds the threshold value. The utility model improves the sensitivity and resolution of the pressure measurement in the 0-8km detection range under the well.