Several major fiber optic sensor development status

Fiber optic gyro Fiber optic gyro interferometric, resonant and Brillouin type, interferometric fiber optic gyro is the first generation, the technology has matured, is in the advancement of mass production and commercialization stage; resonant fiber optic gyro is the second generation, in the laboratory research to the practical advancement of the development stage; Brillouin type is the third generation, is still in the theoretical research stage. Fiber optic gyro structure according to the optical components used in three ways to achieve: small discrete element system, all fiber optic system and integrated optical element system. Currently discrete optical components program has basically disappeared, all-fiber optic system used in open-loop low-precision, low-cost fiber optic gyro, integrated optics gyro with simple process, good overall repeatability, low-cost fiber optic gyro has become the main program of the international high-precision. Fiber optic gyro is mainly composed of light source, detector and other active devices and fiber optic coupler, phase modulator and other passive devices and optical fiber. Foreign research from 1976, to the mid-1990s has been a variety of precision fiber optic gyro for sale, the first in the aerospace and military applications, many products have been applied to civil aircraft and automotive industry. Domestic in the polarization preserving fiber, coupler, multi-functional integrated optical modulator (Y waveguide) and other areas have achieved greater results, close to or reached the international advanced level. In the light source is still under research, in the laboratory conditions of super-emission laser diode can meet the requirements, in engineering applications there are still problems such as reliability and temperature characteristics. Limited to semiconductor technology, the current domestic research is focused on the 1300nm band. The gap between domestic and foreign countries is mainly in productization, immature technology, not formed large-scale production capacity; performance and production capacity of components to be improved. Xi'an femtosecond photoelectric R & D director Mi Lei said to fiber optic online: "China has mass-produced one-thousandth of the precision of the fiber optic gyro, is currently mainly used for missiles and other low-precision areas, for airborne high-precision fiber optic gyro is being developed. Space Age Group fiber optic gyro annual sales have exceeded 200 million yuan, the country has a number of companies in this field of development, mainly focused on the field of medium precision. Currently the core device of the phase modulator, mainly produced by the Beijing Shivetong company, Chongqing 44 is also in production, Xi'an Institute of Optical Machinery is also being developed. Fiber optic ring is generally self-produced by various manufacturers, Wuhan Changyingtong company specializing in fiber optic ring. LED light source is mainly produced by Wuhan Optical Xun, Shenzhen Feikang and other manufacturers." It can be expected that the fiber optic gyro will be in the field of low precision and high precision gradually replace the traditional electromechanical gyro, the future in the aerospace, military, automotive and other fields have great potential for development. Fiber optic hydrophone Fiber optic hydrophone is a fiber optic, optoelectronic technology based on the underwater acoustic signal sensor, it is through the high-sensitivity fiber optic coherent detection, the water acoustic signal is converted to optical signals, and through the fiber optic transmission to the signal processing system is converted to acoustic signal information. Compared with the traditional hydrophone with high sensitivity, wide response bandwidth, not subject to electromagnetic interference and other characteristics, widely used in military and oil exploration, environmental testing and other fields, has great potential for development. Fiber optic hydrophone can be divided into interference type, intensity type, grating type, etc. according to the principle. Interference-type fiber optic hydrophone key technologies have been gradually developed and mature, in some areas of the formation of products; fiber grating hydrophone is the current research hotspot. The key technologies involved in the research of light sources, fiber optic devices, probe technology, anti-polarization fading technology, anti-phase fading technology, signal processing technology, multiplexing technology and engineering technology. Fiber optic hydrophone research began in the late 1970s in the U.S. Naval Laboratory, the developed countries have invested a lot of manpower and resources to do research, and achieved a lot of results. In military applications, with the submarine noise reduction, electric sonar detection sensitivity close to the limit value, fiber optic hydrophone will be useful. China's fiber optic hydrophone research has also made greater progress in some technical indicators to reach the international level, but mainly in the theoretical and experimental stage, practical, engineering fiber optic hydrophone has not been reported. Fiber grating sensors Fiber grating sensors, especially fiber Bragg grating sensors is a hot spot in the field of sensors at home and abroad in recent years. The majority of traditional fiber optic sensors belong to the light intensity type and interference type, light intensity type sensors exist in the light source is not stable, fiber loss and detector aging and other issues, interference type sensors due to the requirements of the two interfering light intensity is equal to the need for a fixed point of reference for the application of inconvenience. Fiber Bragg grating-based fiber grating sensor sensing signal for the wavelength modulation and multiplexing ability, to avoid the above problems of traditional fiber optic sensors. In the building health detection, impact detection, shape control and vibration damping detection applications, fiber grating sensor is the most ideal sensitive components. Fiber grating sensors have a wide range of applications in geodynamics, spacecraft, ship shipping, civil engineering structures, power industry, medicine and chemical sensing. Fiber grating sensor research direction are: (1) with high sensitivity, high resolution, and can simultaneously sense the strain and temperature change sensor research; (2) the development of low-cost, miniaturization, reliable and sensitive detection technology system research; (3) practical application research, including packaging technology, temperature compensation technology, sensor network technology. Currently certain types of fiber grating sensors have been commercialized, but need to be improved in terms of performance and functionality. However, it can be said that fiber grating sensing technology has been close to the mature stage. China's fiber grating sensor research is relatively late, but there has been greater development, with practical, inexpensive wavelength demodulation technology to further develop and improve, fiber grating sensors will have broad prospects for development. Beijing Toplight research manager Shen Kuangyi said, fiber grating sensors are mainly used in oil tank temperature measurement, earth stress measurement, temperature measurement of power equipment and other markets, in the state of the small companies in the state of the cut, science and technology photoelectricity and Pin Ao Optoelectronics and other companies to do a relatively large. Top Optical Research 10 years of experience in the industry analysis, the next 3 ~ 5 years the fiber grating sensor market will be sub-industry, geographically small and medium-sized companies to occupy. Large telecommunications equipment manufacturers are currently interested mainly in the broadband market of radio and television, will not consider entering this field for the time being. Fiber optic current sensor The rapid development of the power industry has led to the increasing capacity of the power transmission system, the operation of the voltage level is getting higher and higher, and have to face the problem of measuring the strong current. In the high-voltage, high-current and strong power power system, the electromagnetic induction-based traditional current sensor (CT for short) exposed a series of serious shortcomings: explosion caused catastrophic accidents; large fault current caused by the magnetic saturation of the iron core; core *** vibration effect; hysteresis effect; poor accuracy; susceptible to interference; large size, weight, expensive, etc., it has been difficult to meet the development of a new generation of digital power network needs. Fiber optic current sensor has become the best way to solve the above problems. Manager Shen believes that the fiber optic current sensor derived from the fiber optic gyroscope technical solutions, is an example of civilianization of military technology, now the technical solutions have not been finalized, in the groping - finalized - and then groping stage. Wuhan long Yingtong technical director Dr. Wang Honghai said that the fiber optic current sensor market is currently 3 ~ 4 domestic manufacturers have small shipments, this year's State Grid bidding situation is about 1,000 or so. Relatively speaking, the dosage is still very small. The current obstacles to the use of real scale or its stability, especially temperature stability. Future Development Trends The rapid development of fiber optic communications led to the emergence of new optical devices and materials for the development of fiber optic sensing system provides the necessary foundation. Fiber optic sensing technology over the past 30 years has made great progress in the development of fiber optic sensing technology, mainly embodied in: into the practical stage; new sensing principles continue to appear. But the current state of development is still far from meeting the actual needs, there are still many topics to be studied: (1) practical research, especially cost-effective; (2) application research; (3) the study of new fiber optic sensors; (4) the study of new sensitive materials, the study of new specialized optoelectronic devices. Therefore, the possible development trends of fiber optic sensors are: (1) problems that cannot be solved by traditional sensors as the main research object of fiber optic sensors; (2) integrated fiber optic sensors; (3) multifunctional all-fiber optic control system; and (4) opening up new fields. For the price of fiber optic sensors, Dr. Wang said that there are many types of fiber optic sensors, specifically fiber optic gyroscope and fiber optic current transformer, about 2 to 3 times the same level of traditional sensors. The long-term stability and reliability of the application is not enough, the price is higher and the intelligent processing of the data obtained is not enough to hinder the large-scale application of important reasons. Specifically on the development of industry applications, Shen manager of fiber optic online, said that the sensing technology is applied to all walks of life, each enterprise's ability to enter the market is limited, so now blossom everywhere, the traditional sensor industry has a mature industrial chain and chain of interests, fiber optic sensing industrialization to have a long-term resistance to the preparation of the war. Fiber optic sensors are expensive and scale-related, but fiber optic sensing backed by the optical communications industry, the long-term cost reduction is no problem. Fiber optic sensing engineering research is a hot spot, technical maturity, cost, industry acceptance, whether there are hidden problems, all need the test of time. An industry to follow the life cycle, fiber optic sensing has a long way to go.