Fiber optics pressure sensor transducer having a temperature compensator

Abstract

Improved fiber optics pressure sensor transducers utilizing fiber optics in an interferometer sensing element. Included is a bellows-type pressure-to-movement converter that translates sensed pressure into linear displacement. That displacement is mechanically coupled to, and thereby varies the length of one leg of a fiber optics interferometer as a function of pressure. A temperature compensator is attached to the sensing or reference optical fiber of the interferometer. The temperature compensator causes corrective changes in the length of that optical fiber to which it is attached, thereby compensating for opposing temperature effects on other parts of the interferometer. Threaded studs attached to flexible stress reducers which are in turn coupled to optical fiber grippers provide means for adjusting interferometer optical fiber pre-tension and rotation to optimize polarization. In combination, the threaded studs with their attached flexible stress reducers, coupled via fiber grippers to the interferometer optical fibers, serve to minimize fiber bending and localized stress points which otherwise might weaken the tensioned fibers of the interferometer. A bourdon tube embodiment of the pressure-to-movement converter having a curved tang and attached flexible link converts rotational motion of the bourdon tube movement end to linear displacement.