MICROMACHINED 125μm DIAMETER ULTRA MINIATURE FIBER-OPTIC PRESSURE SENSOR FOR CATHETER

Abstract

A miniaturized fiber-optic pressure sensor 125μm in diameter has been developed for the measurement in human body [1]. The sensing element is fabricated by micromachining, and attached to the end of an optical fiber using polyimide adhesive layer. A Fabry-Perot interferometer is constituted of a half-mirror at the fiber end and a reflection mirror on the movable thin diaphragm. The intensity of the light reflected at the interferometer is modulated by the pressure, because the optical path difference between the two mirrors of the interferometer varies with the displacement of the diaphragm in dependence on the pressure.