Fiber optic sensors help the development of the Internet of Things

The development of the Internet of Things must rely on a large number of sensors to obtain various environmental parameters, so that more reliable data information for the Internet of Things can be processed by the system to obtain the results that people need.

In recent years, sensors have developed in the direction of sensitivity, accuracy, adaptability, compactness and intelligence. In this process, the new member of the sensor family, the optical fiber sensor, has been favored.

Optical fiber has many excellent properties, such as: resistance to electromagnetic interference and atomic radiation, mechanical properties of thin diameter, soft quality, and light weight; electrical properties of exhaustion, no induction; chemical properties of water resistance, high temperature resistance, corrosion resistance, etc. , It can act as a person's informant in places where people can't reach it (such as high temperature areas or areas that are harmful to people, such as nuclear radiation areas), and it can also exceed the physical limits of people and receive the feelings of people Unreachable outside information.

Basic working principle and application field

The basic working principle of the fiber optic sensor is to send the light from the light source to the modulator through the fiber, so that the measured parameter interacts with the light entering the modulation area, resulting in the optical properties of the light (such as light intensity, wavelength, frequency, phase , Partial normal, etc.) change, called the modulated signal light, sent into the optical detector through the optical fiber, after demodulation, the measured parameters are obtained.

Optical fiber sensors are used for measuring physical quantities such as magnetism, sound, pressure, temperature, acceleration, gyro, displacement, liquid level, torque, photoacoustics, current and strain. The application range of fiber optic sensors is very wide, involving almost all important fields in the national economy and national defense and people's daily life. It can be used safely and effectively in harsh environments. It solves the technical difficulties that many industries have had for many years. Market demand. The application is mainly manifested in the following aspects:

1. The application of interferometric gyroscopes and grating pressure sensors in bridges, dams, oil fields, etc. in the city's construction. Fiber optic sensors can be pre-buried in concrete, carbon fiber reinforced plastics, and various composite materials to test stress relaxation, construction stress, and dynamic load stress to evaluate the structural performance of the bridge during the short-term construction phase and long-term operation.

2. The power system needs to measure the temperature, current and other parameters, such as the temperature detection in the stator and rotor of high-voltage transformers and large motors. Because electrical sensors are susceptible to interference from electromagnetic fields, they cannot be used in such occasions. Use fiber optic sensors. Distributed optical fiber temperature sensor is a new technology developed in recent years for real-time measurement of spatial temperature field distribution. Distributed optical fiber temperature sensor system not only has the advantages of universal optical fiber sensor, but also has the temperature of various points along the fiber The distributed sensing capability of the sensor, using this feature, we can continuously measure the temperature of each point within a few kilometers along the fiber in real time. The positioning accuracy can reach the order of meters, and the measurement accuracy can reach the level of 1 degree. It is very suitable for large-scale intersection temperature measurement. Application occasions.

In actual life, there are many types of fiber optic sensors. However, we attribute these sensor types to two major types, namely, sensor type and light transmission type. Compared with traditional electrical sensors, fiber optic sensors have many advantages, such as strong anti-interference ability, good insulation, and high sensitivity. Therefore, there are currently fiber optic sensors in various fields.

Fiber optic sensors help the Internet of Things to develop market capacity of nearly trillion

Since the appearance of optical fiber sensors, its advantages and applications have aroused great attention from people in various countries. And in-depth research on fiber optic sensing technology. Nowadays, the optical fiber sensor can measure the physical quantities such as displacement, temperature, speed and angle. Nowadays, many western developed countries have focused their research on optical fiber sensors on optical fiber control systems, nuclear radiation monitoring, civilian programs, and many other aspects, and have achieved gratifying results.

China's research on fiber optic sensors started late, and there are many institutes, companies, etc. in-depth research on fiber optic sensors has promoted the development of fiber optic sensing technology. In 2010, Zhang Xuping's Brillouin effect continuous distributed optical fiber sensing technology passed the expert's appraisal. The expert group believes that this technology is very innovative and the technology has reached the world's advanced level, therefore, it has broad development prospects. The development of this technology is mainly the application of the Internet of Things technology, thereby accelerating the development of China's Internet of Things.

Sensors have become an extremely important part of the Internet of Things. Therefore, the performance of the sensor determines the performance of the Internet of Things. It can be said that the main means for the Internet of Things to obtain information is sensors. In this way, the reliability and accuracy of the information collected by the sensor will have a certain impact on the processing and transmission of information by the control node. From this point of view, the reliability and anti-interference of sensors will play a decisive role in the performance of Internet of Things applications.

Application of optical fiber sensing technology in Internet of Things

Through the above analysis, it is known that the development of the Internet of Things must rely on a large number of sensors to obtain various environmental parameters, so as to obtain more reliable data information for the Internet of Things, and then through system processing to get the results that people need. The following is a detailed discussion of the application of optical fiber sensing technology in the Internet of Things.

There are currently four types of fiber optic sensors that are most widely used, namely fiber optic gyro, fiber optic hydrophone, fiber grating sensor and fiber optic current sensor. Among them, there are three types of fiber optic gyroscopes: interference type, resonant type and Brillouin type. Interferometric fiber optic gyroscope is the first technically mature first-generation commercial stage, and resonant fiber optic gyroscope is the second generation in the laboratory research stage. The Brillouin fiber optic gyro is the third generation fiber optic gyro sensor in the theoretical research stage; the fiber optic hydrophone is an underwater acoustic signal sensor based on optical fiber and optoelectronic technology. This sensor is detected by highly sensitive fiber coherent, The sound signal in the water is converted into an optical signal, and then transmitted to the signal processing system through the optical fiber to be converted into a sound signal. This sensor can be divided into interference type, intensity type, grating type and other types according to the principle; the products of the fiber grating sensor include Strain sensors, temperature sensors and pressure sensors, among which fiber bragg grating sensors have been research hotspots in recent years, most of them belong to light intensity type and interference type, and each has advantages and disadvantages.

The development of electric power has been progressing by leaps and bounds since this year. In this case, faced with the measurement of powerful currents, fiber-optic current sensors can well avoid some accidents caused by excessive power.