Convex double-layer pressure sensitive film based on MEMS process and FP cavity optical fiber acoustic sensor

The invention provides a convex double-layer pressure sensitive film based on an MEMS process. The film comprises a soft film and a medium hard film plated below the soft film, the diameter of the soft film is greater than that of the medium hard film; the soft film is a rubber film or a silica gel film made of PDMS, the medium hard film comprises a plurality of first medium layers and a pluralityof second medium layers, the refractive index of the first medium layers is larger than that of the second medium layers, and the first medium layers and the second medium layers are sequentially andalternately stacked from bottom to top. The invention further provides an FP cavity optical fiber acoustic sensor, when the FP cavity optical fiber acoustic sensor is used for collecting transmissionlight for demodulation, due to the fact that the reflectivity of the two cavity faces of the FP cavity is close to 99% through a thin film process, the transmission spectrum is a sharp comb-shaped spectral line, at the moment, the transmission light is received, and an acoustic pressure signal is obtained by demodulating an optical signal. The sensitive film manufactured by the method is large inperipheral deformation quantity, almost has no deformation in the diameter range of an optical fiber mode field, and is high in reflectivity.