Fiber optic sensors: optical communication under a prairie fire

Currently on the market several major fiber optic sensors are:
1 FOG
Interferometric fiber optic gyroscope points, resonant and Brillouin type, interferometric fiber optic gyroscope is the first generation, technically mature, is in advance stage of mass production and commercialization; resonant fiber optic gyroscope is the second generation, in the laboratory research to advance the practical stage of development; Brillouin-type is the third generation, still in theory stage. FOG structure based on the optical components used in three approaches: small discrete systems, all-fiber system and optical component integration system. Discrete optical components present program has been disappeared, all-fiber system with low accuracy in open loop, low-cost fiber optic gyro, the gyro with integrated optical device technology is simple, the overall reproducibility, low-cost high-precision fiber optic gyro in a major international program.

(2) fiber-optic hydrophone
Is a fiber-optic hydrophone based on optical, opto-electronics technology based on the underwater acoustic signal sensors, it is through high-sensitivity optical coherent detection, the acoustic signals into optical signals and transmitted through fiber-optic signal processing systems into acoustic signal information. Compared to conventional hydrophone with high sensitivity, wide bandwidth, response, immune to electromagnetic interference, which is widely used for military and oil exploration, environmental testing and other areas, has great potential for development.
Fiber-optic hydrophone can be divided according to principles of intervention type, strength-based, raster type. Interferometric fiber-optic hydrophone has gradually developed the key technology in some areas of the formation of the product; FBG hydrophone is currently the research focus. Study of key technologies involved in light source, optical devices, sensor technology, the decline of anti-polarization technology and anti-phase fading, signal processing, multiplexing technology, and engineering technology.

3 fiber Bragg grating sensors
Fiber Bragg grating sensors, especially fiber Bragg grating sensor is at home and abroad in recent years, sensor research focus. The vast majority of traditional fiber-optic sensor type and intensity interferometer, there is light intensity sensor instability, optical loss and detector aging issues, interference-type sensor due to the requirement of two interfering light intensity equal to a fixed reference point for the application needs inconvenient.
The fiber Bragg grating-based fiber Bragg grating sensors and sensor signal wavelength modulation multiplexing ability, to avoid the above problems of traditional fiber-optic sensors. Health monitoring in the building, impact testing, testing shape control and vibration damping applications, FBG sensors are ideal sensitive components. FBG sensors in geodynamics, spacecraft, ship navigation, civil engineering structures, power, pharmaceutical and chemical sensing in a wide range of applications.

4 fiber-optic current sensors
The rapid development of power industry driven power transmission system capacity increasing operating voltage level higher and higher, had to face a strong current measurements. In the high-voltage, high current and high power electrical systems to conventional electromagnetic induction-based current sensor (referred to as CT) revealed a series of serious shortcomings: an explosion caused by a catastrophic accident; large fault currents cause magnetic core saturation; iron core resonance effect; lag effect; accuracy is not high; susceptible to interference; bulky, heavy, expensive, etc., have been difficult to meet the new generation of digital power grid development needs. Fiber-optic current sensor as the best way to solve the above problems.

Compared with the conventional sensor technology, fiber-based sensors have the following main advantages:
1 light weight, compact, easy multiplexing
(2) anti-poor environment, anti-electromagnetic interference, resistance to chemical corrosion
3 points in the sensor without electricity, can be distributed sensing distance
4 can be low-cost mass production

Development trend of optical fiber sensors may include:
1 traditional sensors can not solve the problem as a main object of study of fiber optic sensors;
2 integrated optical sensor;
3 multi-functional all-optical control system;
4 open up new areas.

Following the optical fiber communication, optical fiber sensing ushered in an important opportunity for development, in security, military, oil / gas, electricity, and enjoys a wide range of scientific applications and great value, especially in Western developed countries, more Liaoyuanzhishi, thrive! done using single-frequency fiber laser optical sensor, the principle is the optical frequency optical time domain reflectometry.