Optical fiber sensor technology is accompanied by the rapid development of optical communication and formation of the new technology. In optical communication systems, optical fiber is light signal long distance transmission medium. When light waves in optical fiber transmission, the characterization of the waves of amplitude, phase, frequency, polarization characteristics parameters, due to external factors such as temperature, pressure, magnetic field, electric field and check the effect of change, it can be used for optical fiber sensor components, detection result in the size of the light signal changes of various physical quantities, this is the fiber optic sensor.

Caused by external factors to physical quantities of detection device, optical fiber phase change is called a phase modulation sensor type optical fiber sensor, other and amplitude modulation sensor type, polarization modulation type, light type etc. Various kinds of fiber optic sensor.

Compared with other sensors, optical fiber sensor is characterized by:

(1) resistance to electromagnetic interference suppression, good electrical insulating performance, corrosion resistance, security department, thus can be used in strong electromagnetic interference, flammable and explosive, corrosive environments, etc.

(2) the high sensitivity, light weight, small volume, light path variable, etc., has a broad application and profound physical content.