Further distinction is often made in the case of fiber sensors as to whether measurands act externally or internally to the fiber. Where the transducers are external to the fiber and the fiber merely registers and transmits the sensed quantity, th. Further distinction is often made in the case of fiber sensors as to whether measurands act externally or internally to the fiber. Where the transducers are external to the fiber and the fiber merely registers and transmits the sensed quantity, the sensors are termed extrinsic sensors. Where the sensors are embedded in or are part of the fiber and. The strategies of sensing are based on either measuring the intensity change in one or more light beams or measuring the phase change in the light beams by causing them to interact or interfere with one another. As a result sensors in this class are called either intensity or interferometric sensors. Techniques used in the case of intensity sensors. This class is composed of single point sensor or distributed sensor based on whether sensors operate only at a single point or over a distribution of points. In the case of a point sensor, the transducer may be at the end of a fiber the sole purpose of which is to bring a light beam to and from the transducer. Examples of this sensor type are inter.
