The hottest optical fiber sensor is the best means

Optical fiber sensor is the best means of earthquake monitoring at present. Editor's note: the huge casualties and property losses caused by the Wenchuan M8.0 earthquake have made earthquake prediction a hot topic in the scientific community and even the whole society. Professor raoyunjiang, Dean of the school of communications at the University of Electronic Science and technology, who has long been engaged in the research of optical fiber sensors, said that optical fiber sensors are the best means of earthquake monitoring at present

optical fiber sensors installed on bridges

the huge casualties and property losses caused by the Wenchuan M8.0 earthquake have made earthquake prediction a hot topic in the scientific community and even the whole society

at the Xiangshan Scientific Conference on "scientific analysis of the occurrence mechanism and subsequent disaster of the Wenchuan earthquake in Sichuan" urgently held on May 19, many scholars proposed the work of "mass measurement and mass prevention" of earthquakes; At the same time, multi-disciplinary comprehensive early warning and overall thinking methods should be used to predict earthquakes, such as infrasound wave, ground stress, geoelectric pulse, ground micro motion and so on, so as to improve the level of earthquake prediction

"due to long-distance telemetry, it can withstand harsh environment (high temperature above 500 ℃) , high sensitivity, easy connection and other outstanding advantages. Optical fiber sensors may be the best means of earthquake monitoring at present. Once a permanent optical fiber sensor network that can monitor earthquakes is established near the seismic zone, it can timely monitor underground abnormalities, give early warning of possible earthquakes, and avoid casualties and property losses as much as possible. " Professor raoyunjiang, Dean of the school of communications at the University of Electronic Science and technology, who has been engaged in the research of optical fiber sensors for a long time, said

booming research on optical fiber sensors

modern information technology is composed of information collection, transmission and processing technology, so sensor, communication and computer technology have become the three pillars of information technology. The invention of optical fiber is a major achievement in the history of world science and technology, which has caused a series of modern scientific and technological changes in the information field. If this Japanese company is able to build a factory here, one of its most successful applications is optical fiber communication and optical fiber sensing

in recent years, sensors have developed in the direction of miniaturization, digitalization, intelligence and networking, aiming to promote the development of its electric vehicles. In this process, optical fiber sensors, a new member of the sensor family, are favored. Optical fiber sensors have many excellent properties, such as anti electromagnetic interference and atomic radiation, light weight, small volume, insulation, high temperature resistance, corrosion resistance, etc. they can accurately measure various parameters such as strain, pressure, temperature, vibration, sound field, refractive index, acceleration, voltage, gas, etc., and can adapt to extremely harsh environments. At the same time, due to the low transmission loss and wide bandwidth of optical fiber, optical fiber sensors have unparalleled advantages over traditional sensors in terms of group and transmission distance

it is precisely because the optical fiber sensor has many unique advantages, which can solve many measurement problems that cannot be solved by traditional sensors. Therefore, the four groups of parameters displayed on the screen are force value, times, elongation and clamping length. Since its inception, it has been widely used in various fields such as medical treatment, transportation, electric power, machinery, petrochemical industry, aerospace, geology and geotechnical engineering

application in earthquake monitoring has a technical foundation.

with the support of the National Science Foundation for Distinguished Young Scholars, the national key natural science foundation and the general projects of the National Natural Science Foundation, raoyunjiang led his research team to conduct extensive and in-depth research in the field of optical fiber sensors, and solved many key and difficult problems. Their research results laid a solid foundation for the application of optical fiber sensors in the field of earthquake monitoring

according to raoyunjiang, in the research of optical fiber multi parameter sensing, with the development of science and technology, it is necessary to measure the changes of two or more parameters at the same time in many important occasions. For example, in the health monitoring of intelligent materials and structures, the strain, vibration and temperature are measured at the same time, and the underground physical quantities such as the internal stress, temperature, displacement and inclination of the geological plate in the earthquake, as well as the vibration, underground fluid pressure, underground magnetic field and so on; Simultaneous measurement of pressure, temperature and flow in oil and natural gas exploitation. Therefore, while using composite optical fiber sensors to achieve multi parameters, measurement technology is not only a very important and challenging scientific research topic in the field of optical fiber sensors, but also in the field of sensors

in order to solve this problem, raoyunjiang research group proposed a series of optical fiber multi parameter sensing methods for the first time in the world. The tunnel is equipped with signal traffic lights, instigation lights and emergency lights. A new method of simultaneous measurement of multiple parameters is realized by using integrated sensors

in addition, integrated optical fiber sensors are also applied to national defense and health monitoring of large bridges. At present, this kind of sensor has been successfully applied to the safety real-time monitoring of five bridges in Chongqing. The experience gained from the application of this kind of optical fiber sensor in civil engineering structures is very helpful for seismic monitoring

excellent group ability is one of the characteristics of the new generation of optical fiber sensors. In response to this challenge, raoyunjiang research group proposed a high-capacity optical fiber sensor network based on multiplexing method for the first time in the world. By transforming the traditional optical fiber sensor into a sensor with a cavity length of up to several millimeters, combined with some scientific methods, a network with the ability to multiplex more than 1000 optical fiber sensors is established, Thus, it takes the lead in solving the bottleneck of poor multiplexing ability of traditional optical fiber sensors in the world, and lays a technical foundation for the large-scale application of this kind of sensors. This kind of sensor is currently being used in the health and safety monitoring of oil (gas) pipelines

the research group also turned ultra long distance optical fiber sensing into reality. Ultra long distance telemetry is another feature of the new generation of optical fiber sensors. How to achieve a measurement distance of more than 100 kilometers is another challenge in the field of optical fiber sensing. Facing this challenge, raoyunjiang research group has prepared a measurement system with an ultra long distance measurement capability of 250 kilometers for the first time in the world, and the system has been used as an optical fiber fence in the safety protection and anti-terrorism of important facilities, and is expected to be important in earthquake monitoring

in addition, raoyunjiang research group has also made major breakthroughs in the research of micro nano optical fiber sensing technology. They have solved many problems existing in the ability of conventional electrical sensors to withstand harsh environments

many relevant achievements of raoyunjiang research group have been successfully used to monitor the stress, displacement, inclination and vibration of bridges, and have been industrialized, so they have a good foundation