Abstract: A fiber optic interferometric sensor system utilizing a reference transducer and an optical source having a short coherence length in comparison to the optical transit time through the sensor. The optical source is used to interrogate a remotely located fiber optics sensor which has an optical path difference between two reflecting surfaces or between one reflecting surface and a beam transmitted through the sensor such that the optical beams are incoherent for the optical source used. The reflected and transmitted beams are then coupled to a reference transducer, located remotely from the sensor and preferably near the electronic processing circuitry. The reference transducer is designed with an optical path length difference to produce a coherent combination for the optical path length differences of both the sensor and the reference transducer thereby forming a highly sensitive interferometer.