a method to assemble optical fiber devices and a fiber optic sensor is provided . it features a small adhesive joint between the fiber and a capillary tube by means of a small recess carved on the side of the fiber . this recess acts as a reservoir for the adhesive during the insertion of the fiber inside the tube . then , the tube is heated so that the adhesive swells out of the recess to make the joint between the tube and the fiber . this method is used to assemble a fiber optic fabry - perot interferometer . this interferometer can be used as a sensor for the measurement of a number of physical parameters .