اصل کار و کاربرد سنسورهای فیبر نوری توزیع شده

سنجش فیبر نوری توزیع شده technology has important applications in fiber optic characterization, fault localization, and monitoring of fiber optic environmental temperature, استرس, and vibration. Optical time-domain reflection technology, optical time-domain analysis technology, and optical frequency-domain analysis technology are several commonly used technologies in distributed fiber optic sensing technology.

Distributed fiber optic sensors have been widely used in fields such as power, پتروشیمی ها, حمل و نقل, مهندسی عمران, and aerospace. با این حال, with the increasing production safety requirements in various industries, single function distributed fiber optic sensors can no longer meet the needs. In order to have a more comprehensive understanding of engineering safety conditions, users often need to simultaneously monitor parameters such as temperature, ارتعاش, and strain in real-time from all angles. به طور کلی, at least two different sets of distributed fiber optic sensors need to be equipped to meet the requirements.

When an optical fiber is affected by external factors such as temperature, استرس, ارتعاش, و غیره, the intensity, فاز, فرکانس, and other parameters of the transmitted light in the fiber will change accordingly. By detecting these parameters of the transmitted light, corresponding physical quantities can be obtained. This technology is called fiber optic sensing technology. The characteristics of the fiber optic itself, such as non electrification, electromagnetic resistance, مقاومت در برابر تشعشع, مقاومت در برابر ولتاژ بالا, no spark generation, and good insulation performance, make the fiber optic sensing system the mainstream of sensor systems and gradually replace traditional sensor systems. When the physical quantities on the optical fiber, such as pressure, دما, رطوبت, میدان الکتریکی, میدان مغناطیسی, و غیره, change, it will cause changes in the physical characteristics of the optical fiber, resulting in various optical effects of the transmitted light waves in the optical fiber, such as scattering, قطبی شدن, intensity changes, و غیره. By detecting changes in light waves in optical fibers, physical quantities such as temperature, فشار, deformation, and water level can be detected. در سالهای اخیر, the rapid development of optoelectronic devices, especially semiconductor lasers, wavelength division multiplexing and optical coupling technology, detection and processing of optoelectronic signals, and other technologies, has made it a reality for optical fibers to be used as distributed sensor systems.

Distributed fiber optic sensing technology is widely used for monitoring the condition of large substrates such as buildings, پل ها, and slopes due to its advantages of distributed measurement, فاصله اندازه گیری طولانی, ضد تداخل الکترومغناطیسی, and high insulation strength. It is also applied in the field of electrical engineering to measure temperature and strain of electrical equipment such as submarine cables and overhead transmission lines, and has a very broad application prospect. در حال حاضر, there are few reports on the detection of transformer winding temperature and strain based on distributed fiber optic sensing technology.
Fiber optic sensors have many advantages such as strong resistance to electromagnetic interference, حساسیت بالا, عایق الکتریکی خوب, safety and reliability, مقاومت در برابر خوردگی, and the ability to form fiber optic sensing networks. بنابراین, they have broad application prospects in various fields such as industry, کشاورزی, زیست پزشکی, and national defense.
در سالهای اخیر, the Brillouin optical time-domain analyzer, as a typical representative of distributed fiber optic sensing technology, has received widespread attention. Compared with other fiber optic sensors, the Brillouin optical time-domain analyzer has advantages such as high spatial resolution, ultra long distance sensing, and dynamic measurement. It can simultaneously measure physical quantities such as temperature and microstrain with high precision. Due to the fact that optical fibers serve as both sensor components and signal transmission channels, using optical signals as transmission signals can effectively reduce structural costs.

Distributed fiber optic sensing technology is widely used in pipeline leakage monitoring technology due to its wide sensing space range, the same fiber for sensing and transmission, ساختار ساده, convenient use, low cost of signal acquisition per unit length, and high cost-effectiveness.

Traditional sensors are mostly electric type, with small measurement range and difficult grid connection. علاوه بر این, point sensors have high maintenance costs when measuring large ranges and long distances. در مقابل, the sensors of fiber optic sensors are fiber optic, which has a stable structure, مقاومت در برابر تداخل الکترومغناطیسی, مقاومت در برابر خوردگی, اندازه کوچک, و کم هزینه. علاوه بر این, the coverage of fiber optic is wide, and it can measure systems with a wide range and spatial distribution. بنابراین, since the late 1970s, distributed fiber optic sensing has been widely developed, with the emergence of optical time domain reflection technology (OTDR), Raman optical time domain reflection technology (ROTDR), Brillouin optical time domain reflection technology (BOTDR), and phase sensitive optical time domain reflection technology（ Φ- OTDR, و غیره. در حال حاضر, Raman optical time-domain reflection (ROTDR) technology based on temperature measurement is relatively mature. در میان آنها, Raman optical time-domain reflection (ROTDR) technology injects pulsed light into the fiber, and the temperature effect of backward Raman scattering spectrum is generated during the propagation of light in the fiber. هنگامی که کوانتوم نور فرودی با مولکول های ماده در فیبر برخورد می کند, برخوردهای الاستیک و غیر ارتجاعی رخ می دهد. هنگامی که برخورد الاستیک رخ می دهد, هیچ تبادل انرژی بین کوانتوم نور و مولکول های ماده وجود ندارد, و فرکانس کوانتوم نور به هیچ وجه تغییر نمی کند, در نتیجه نور پراکنده ریلی همان طول موج نور فرودی را حفظ می کند; در برخوردهای غیر ارتجاعی, تبادل انرژی رخ می دهد, and light quanta can release or absorb phonons, resulting in the generation of a longer wavelength Stokes light and a shorter wavelength anti Stokes light. به دلیل حساسیت نور ضد استوکس به دما, این سیستم از کانال نوری استوکس به عنوان کانال مرجع و کانال نوری ضد استوکس به عنوان کانال سیگنال استفاده می کند.. The ratio of the two can eliminate non temperature factors such as light source signal fluctuations and fiber bending, دستیابی به جمع آوری اطلاعات دما.

FJINNO فراهم می کند distributed fiber optic temperature measurement systems, which are directly sold by manufacturers and can be widely used in comprehensive pipe galleries, ترانشه های کابلی, خطوط لوله نفت و گاز, پست ها, و غیره.

سنسور دمای فیبر نوری, سیستم مانیتورینگ هوشمند, تولید کننده فیبر نوری توزیع شده در چین