High-sensitivity intrinsic fiber-optic Fabry-Perot pressure sensor

A new configuration for a pressure sensor in which the motion of a diaphragm produces strain in a fiber Fabry-Perot interferometer (FFPI) is described. The single-mode fiber containing the interferometer is bonded at one end to the stainless-steel diaphragm. The fiber is also attached beyond the interferometer to the sensor housing in such a manner that it is always under tension and experiences a strain in proportion to the deflection of the diaphragm. An analysis relating the expected interferometer phase change to pressure is presented, and the dynamic response of the FFPI sensor to pressure changes produced by an air pump is in good agreement with that measured with a conventional pressure sensor.