Fiber-optic pressure sensor, variants and method for producing a resilient membrane

The inventions relate to measurements of a hydrostatic and/or fast-changing pressure by optical means, and are suitable for aerodynamic investigations of aircraft and small spacecraft, in robotics, including small force micro-clamps, in remote pressure monitoring (in wells, vessels, cylinders), in medicine and medical and biological investigations, hydroacoustics, security systems. The object is to improve the sensitivity and enhance the temperature and vibration stability of a pressure sensor. The pressure sensor is a low Q-factor Fabry-Perot cavity/interferometer 6 at the end of a single-mode optical fiber 1 with the 4% Fresnel reflection from the silica glass/air interface. Another movable mirror of the cavity is formed by an end face 10 of a short (1-3 mm) optical fiber length 9 having a small inertial mass and inserted into the center of a flexible membrane 9 of 500-700 mum in diameter, tightly sealing a small air volume of about 1-3 mm3 inside a second capillary 3 with the external diameter of 0.5 to 0.9 mm. End faces 7 and 10 of the optical fibers 1 and 9 forming the Fabry-Perot cavity 6 with a gap of about 50 mum are placed inside the capillary 2 with the internal diameter of about 145 mum. The temperature stability of the sensor is DELTAP/DELTAT 0.001 atm/° C.