With the continuous development of science and technology, the use of electric power electrical equipment safety has been constantly concerned. Optical fiber temperature measurement in the power system and oil and gas pipeline application range gradually into people's vision, but for the operation principle we know little, the following to introduce the principle of fluorescent fiber temperature measurement, distributed fiber temperature measurement principle, fiber grating temperature measurement principle. Optical fiber temperature measurement can not only be used in the field of electric power, petroleum and petrochemical, but also in the field of scientific research and experiment. Based on the fluorescence lifetime of the temperature measurement of the optical fiber, generally speaking, the outer electrons of the fluorescent material molecules are in a relatively stable state, when the excited light is illuminated, the electron absorption energy transition will appear. After the excitation light disappears, it is allowed to return to the ground state, but the energy keeps radiating, creating fluorescence. For its specific temperature measurement, the temperature of the material surface is related to the decay of the fluorescence afterglow itself, and the so-called afterglow decay is actually the fluorescence lifetime. There is a direct relationship between the length of the fluorescence lifetime and the temperature. After the temperature of the fluorescent substance is determined, the actual afterglow retention time is the lifetime, which itself is monotonous with the current signal. Therefore, through the characteristic curve, the corresponding material can be selected as the probe, and through the relationship between the detected current value and the time stent, the surface temperature can be clearly defined, and then the temperature of the monitoring point can be determined. In the project implementation, compared with the normal operating temperature detection, the temperature after the failure increases abnormally, so the detection significance is greater.

Endoscope, an examination device that can directly enter the natural human cavity, provides doctors with sufficient diagnostic information to treat the disease. There are many kinds of endoscopy, including gastrointestinal endoscopy, thoracic laparoscopy, tracheoscopy, hysteroscopy, ureteroscopy, etc. Different kinds of endoscopes, applied in different departments. Gastroenterology department, cardiothoracic surgery department, urology department, gynecology department, respiratory department and other departments, all need to use medical endoscopy for diagnosis or treatment. However, the traditional endoscope structure is complex and difficult to thoroughly clean and disinfect. The application of the same endoscope between different patients can easily lead to cross-infection, which can cause serious damage to the health of the infected person and even death. After years of exploration by endoscope enterprises, the disposable endoscope is on the "stage". Its appearance effectively solves the problem of cross-infection, and there is no loss of endoscope for disposable use, which can ensure that each unpackaging endoscope is in the best state, and improve the surgical efficiency to a certain extent. In addition, disposable endoscopy can also enable hospitals to effectively control the cost related to endoscopy, and promote the promotion of endoscopic surgery in primary hospitals. The clinical application of medical endoscopy technology mainly focuses on diagnosis and treatment. Through different mirror bodies, it provides good operating field and space for clinicians in various parts of the human body, which is convenient for clinicians to conduct minimally invasive diagnosis and minimally invasive treatment. Endoscopy technology brings operational space for minimally invasive treatment. Minimally invasive treatment will already become one of the important branches of future medical development. Compared with traditional open surgery, minimally invasive surgery has the characteristics of less trauma, less bleeding and faster postoperative recovery. With the improvement of scientific and technological level, minimally invasive treatment techniques and related instruments have become more mature and reliable, and some minimally invasive surgery has become the first-line treatment plan in clinical medicine. Usually a traditional endoscope host is about millions of yuan, soft mirror tens of thousands of yuan, plus maintenance costs, disinfection costs, human expenditure, the cost is not cheap, grass-roots institutions basically "can not afford to buy" also "can not afford to use". The serious lack of endoscopic resources at the grassroots level is the vision of disposable endoscope entering the grassroots level to solve the lack of medical resources of the public. As an emerging force, disposable plastic endoscope can realize immediate examination, obtain information about patients' diseases and complications, and improve the level of primary medical services and the ability of patient management. Due to its convenience and low cost advantages, it is suitable for various primary medical institutions and doctors, which is helpful to achieve rapid diagnosis and treatment, screening and referral and diversion.

Holmium laser is a pulsed laser with a wavelength of 2.1 μ m, which has strong safety and wide applicability compared with the commonly used extracorporeal shock wave lithotripsy and pneumatic ballistic lithotripsy. In the process of lithotripsy, stones rarely run, and the return rate is very low, so the efficiency is greatly improved. It can be directly crushed through cystoscopy, ureteroscopy and percutaneous nephroscopy, without causing tissue damage. And the holmium laser fiber is flexible, so it can effectively treat ureteric and kidney stones in any site. The study shows that the single success rate of endoscopic holmium laser lithotripsy is more than 95%, and the treatment of bladder stones can reach 100%. The procedure is non-invasive or minimally invasive, and the patient is basically painless. There is no risk of perforation, bleeding, but also the combined treatment of urinary tract tumor, ureteral polyps, stricture and so on. The specific process is soft ureteroscopic holmium laser lithotripsy is to use a fiber optic lens with about 3mm in diameter, inserted into the ureter through the urethra and bladder to the renal pelvis and renal calyx. Holmium laser fiber is used to remove and drain the upper ureteral stones and kidney stones. The use of human natural urinary tract, without making any incision in the body, is a pure urology cavity minimally invasive technique, so it is favored by patients.

Fiber optic gyro, or FOG, is a high precision instrument using optical fiber technology. It works intuitively, like "dancing" light in a fiber. When light travels through the fiber, the propagation path in it also changes if the fiber rotates. By accurately measuring this change, the optical fiber gyro can calculate the rotation speed and direction of the optical fiber. The key of fiber optic gyro lies in its high-precision optical system and electronic signal processing system. The optical system ensures that the light travels stably through the optical fiber, while the electronic system is responsible for receiving and processing the optical signals to obtain accurate angular velocity data. Due to its high sensitivity, rapid response and long-term stability, FFG has been widely used in aviation, aerospace, navigation and other fields, providing an important means of angular velocity measurement for navigation and control systems.

To handle the optical fiber end and linker grinding, need to rely on advanced technology equipment and exquisite technology. First of all, the high-precision grinder is used to grind the optical fiber end slightly to ensure the smooth and smooth end surface. Next, polishing is performed with specially designed polishing tools to eliminate subtle scratches and irregularities. For the linker, a special grinding and polishing process is used to ensure its accurate docking with the optical fiber end. Throughout the process, the precise control system and on-line detection technology ensure that every step is accurate.

Distributed acoustic sensing (DAS) technology realizes the real-time monitoring of the optical cable or pipeline by using the backward Rayleigh scattering signal in the optical fiber. The technology is based on a phase-sensitive optical time domain reflector (Φ -OTDR) to reconstruct and detect events such as sound or vibration by detecting the backscattering signal generated when coherent pulse light propagating through the optical fiber. In the optical cable monitoring, the DAS system can accurately restore the sound information around the optical cable, such as vehicles, man-made damage, etc., and filter through the intelligent analysis function, interference signals, to ensure the accurate identification of events. For pipeline monitoring, DAS technology can simultaneously measure various parameters, such as acoustics, temperature, pressure, strain and hole noise, and quickly and accurately detect and classify leakage events, third-party interference and other threats, providing a strong guarantee for the safe operation of the pipeline.

The loss is mainly caused by the scattering and escape of light generated by the fiber during bending.When the light is transmitted in a curved fiber, part of the light will escape from the fiber due to the changing propagation speed and direction of the light in the medium, thus causing the loss of the optical signal.In addition, the propagation of light in the optical fiber is through full reflection, and at the bend, the degree of incidence angle of light may exceed the critical angle of full reflection, resulting in scattering phenomenon, which will also cause the loss of optical signal.The size of the macrobending loss is affected by many factors, including the bending radius, the type and material of the fiber, and the outer coating of the fiber. A smaller bending radius will increase the scattering and escape of light, resulting in increased macrobending loss.The special outer coating can reduce the scattering and escape of light, thus reducing the macrobending loss.

The offshore operation technology of the oil and gas industry is the key to ensure the smooth development of offshore oil and gas resources.Optical fiber and cable and oil field sensing technology play a vital role. With its high-speed and large-capacity data transmission capacity, optical fiber and cable provides a stable and reliable communication guarantee for offshore operations. Through optical fiber and cable, the operation platform can obtain the monitoring data of submarine oil and gas Wells in real time to ensure the safety and efficiency of the operation process.Oilfield sensing technology realizes real-time monitoring and early warning of oil and gas Wells through various sensors arranged on the sea floor. These sensors can sense the key parameters such as pressure, temperature and flow of the wellhead, and provide decision support for operators to work to prevent potential safety risks.With the continuous development of science and technology, the offshore operation technology is also constantly innovating and improving. In the future, optical fiber and cable and oilfield sensing technology will continue to provide strong support for the deep-sea development of the oil and gas industry, and promote the sustainable utilization of offshore oil and gas resources.

The research team at NASA's Armstrong Flight Research Center has made a breakthrough in developing a technology called a "fiber-optic sensing system."The core is to use the optical fiber as a sensing element to realize the real-time monitoring and data feedback of the structural strain, shape, temperature and other key parameters by capturing the physical characteristic changes when the optical waves are transmitted in the optical fiber. Optical fiber sensing system shows great potential in the field of aircraft research with its high sensitivity, strong anti-interference ability and excellent stability. It can accurately capture the tiny deformation and temperature fluctuations of the structure in a complex environment, providing rich and accurate data support for designers, and greatly improve the research accuracy and design efficiency. Its high-precision and long-distance sensing capabilities give it promising prospects in construction, Bridges, energy and other fields. With the continuous progress of technology, optical fiber optic sensing systems will play a key role in more fields to promote the technological innovation and development of related industries.

It is well known that the optical fiber in the general sense is composed of a fiber core, cladding layer and coating layer. Among them, the fiber core, cladding determine its optical characteristics, generally with molten quartz in the environment of 2000℃ pull down, high temperature performance naturally need not say much. In the process of quartz glass pull, its surface will inevitably leave subtle cracks, used by a kinds of environmental stress, crack may rapidly expand and even break, so in the first time to help it put on a layer of sheath —— coating layer, to greatly improve its mechanical characteristics, make it more bending more tensile. It is understood that at domestic and foreign, the application scenario of high temperature resistant optical fiber is very wide. In the exploitation of oil and natural gas, the oil well temperature measuring optical cable needs to be able to withstand the underground high temperature and high pressure environment, and then it is necessary to use the high temperature resistant optical fiber. In thermal power generation, the real-time monitoring of boiler temperature and pressure also requires the stable transmission of high-temperature resistant optical fiber. In addition, in the automotive industry, high-temperature resistant optical fibers are used in on-board communication and entertainment systems to ensure the stable transmission of information in high-temperature engine and exhaust system environments. In the field of aerospace, the high temperature resistance performance of communication equipment is extremely high. The application of high temperature resistance optical fiber can improve the reliability and stability of communication equipment in high temperature environment. Polyimide (Polyimide, PI), with an excellent temperature range of-190℃ ~ + 385℃, has penetrated into every aspect of our lives since DuPont was first commoditized in 1961. For example, the flexible circuit board (FPC), often used in electronic products, is 280℃ lead-free welding and is made of polyimide; it is also made into fabric for firefighters, astronauts, and racers. In theory, 385℃ is the upper temperature limit of the polyimide, regardless of higher temperatures. High temperature resistant metal coated fiber, by coating the surface of the bare fiber with a layer of high temperature resistant metal material, such as aluminum, copper or gold, to improve the performance of the fiber in high temperature environment. This fiber performs well at extreme temperature conditions and has excellent resistance to chemical corrosion and mechanical bending. High temperature-resistant metal-coated optical fibers are widely used in areas that need to withstand high temperature and corrosive environments. For example, metal-coated optical fibers all play an important role in nuclear radiation, high-energy and strong laser transmission, welded fiber beams, and medical applications. In addition, in the field of high temperature sensing fiber, it can be used as turbine sensing fiber, oil and gas well fiber, engine sensing fiber, etc., to withstand the work demand in high temperature environment. Metal optical fibers are also often used as gas-tight optical fibers.

Optical fiber hydrophone system is a complex sensing system, which mainly uses optical fiber sensing technology to realize the conversion, transmission and processing of underwater sound signals. As the core part of the system, the implementation process are crucial to the performance of the whole system. The components of optical fiber hydrophone mainly include wet end and dry end. The wet end, as the sensing end, consists of the optical fiber hydrophone sensor probe and the transmission optical cable used to transmit the optical signal. The sensor probe is the core component of fiber-optic hydrophones, which can receive underwater sound signals and convert them into optical signals. The dry end mainly includes the light source of optical fiber hydrophone, optical passive device, photoelectric conversion module and signal demodulation processing module. The light source is responsible for providing stable optical signals. The optical passive device is used to control the transmission and modulation of the optical signal. The photoelectric conversion module converts the received optical signal into an electrical signal, and the signal demodulation processing module demodulates and processes the electrical signals to extract useful sound information.

The core technologies of machine vision include image acquisition, image pre-processing, feature extraction, target detection and recognition, etc. First, machine vision needs to obtain the image through devices such as cameras, and then preprocess the image, including denoising, enhancement, geometric correction, etc., to eliminate the interference and noise in the image. Object detection and recognition is one of the important tasks of machine vision. By training models and using machine learning algorithms, machine vision can identify and locate target objects in the image, such as faces, vehicles, product defects, and so on. This provides very valuable applications for automated production, intelligent security and intelligent transportation. The development of machine vision technology benefits from the improvement of computer computing power, the improvement of sensor technology and the development of artificial intelligence technology such as deep learning. These advances have led to significant improvements in accuracy, real-time, and adaptability.