Fabrication of a high temperature-resistance optical fibre micro pressure sensor

A micro diaphragm-based Extrinsic Fabry-Perot Interferometric (EFPI) pressure sensor with high temperature immunity is described. The EFPI pressure sensor consists of a single mode silica glass optical fiber, a glass capillary and a glass diaphragm, which are fused together using a conventional fusion splicer. This eliminates the need for the use of other joining materials, e.g. epoxy, allows any thermal mismatch between different materials to be almost completely eliminated and hence the sensor is capable of high temperature operation. In addition, the EFPI pressure sensor is cheap and relatively easy to produce as only splicing, polishing and wet etching are necessary. Moreover, due to its small size, a frequency response of several MHz can be achieved.