Optical fiber-based sensing instrumentation has been demonstrated to be especiallyattractive for the measurement of a wide variety of physical and chemical parameters because of such inherent advantages as I) an immunity to electromagnetic interference, 2) avoidance of ground loops, 3) capability of responding to a wide variety of measurands, 4) avoidance of electric sparks. 5) resistance to harsh environment, 6) remote operation, 7) capability of multiplexing. and 8) ease of integration into large-scale fiber networking and communication systems. Because of these inherent advantages, fiber sensors are therefore attractive to the oil industry.