CN110954298A - Optical frequency domain reflectometer based on industrial all-in-one machine - Google Patents
Optical frequency domain reflectometer based on industrial all-in-one machine Download PDFInfo
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- CN110954298A CN110954298A CN201911281452.0A CN201911281452A CN110954298A CN 110954298 A CN110954298 A CN 110954298A CN 201911281452 A CN201911281452 A CN 201911281452A CN 110954298 A CN110954298 A CN 110954298A
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- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
- G01M11/3172—Reflectometers detecting the back-scattered light in the frequency-domain, e.g. OFDR, FMCW, heterodyne detection
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Abstract
The invention relates to an optical frequency domain reflectometer based on an industrial all-in-one machine, which comprises an optical fiber to be tested, a total control technology and an optical frequency domain reflection technology, wherein the optical fiber to be tested is electrically connected with a circulator and an auxiliary interferometer, the output ends of the circulator and the auxiliary interferometer are electrically connected with differential absorption and double balanced absorption, the output ends of the differential absorption and the double balanced absorption are electrically connected with an analog signal conditioner, the output end of the analog signal conditioner is electrically connected with a nonlinear frequency sweep corrector and an ADC, the total control is electrically connected with the nonlinear frequency sweep corrector, the ADC, a laser frequency control and a digital signal processing, and the output end of the laser frequency control is electrically connected with a narrow-line-width frequency sweep laser. The optical frequency domain reflectometer based on the industrial all-in-one machine overcomes the defects of OTDR in distance resolution and OLCR in measuring distance in principle, and can realize the measurement of high distance resolution, high sensitivity and medium distance.
Description
Technical Field
The invention relates to the technical field of optical frequency domain reflectometers, in particular to an optical frequency domain reflectometer based on an industrial all-in-one machine.
Background
The optical time domain reflectometry technique realizes distributed measurement by measuring the echo response of an optical fiber to an optical pulse excitation signal, and has the advantages of relatively low technical difficulty, long measurement distance and limited distance resolution, and the fundamental reason is that the intensity of an echo signal of an OTDR is directly related to the energy of an injected optical pulse, and to realize high distance resolution, a narrow excitation optical pulse must be injected, so that the pulse energy is reduced, and the measurable distance is shortened, therefore, only distributed measurement with low distance resolution can be realized, and the representative methods are as follows: the method comprises the steps of Rayleigh scattering OTDR for trunk optical cable fault detection, Brillouin scattering OTDR for distributed stress measurement, Raman scattering OTDR for distributed temperature measurement, Optical Frequency Domain Reflection (OFDR) technology, backward reflection measurement technology based on frequency domain analysis, and coherent optical signals are distributed to a reference arm and a signal arm of a fiber interferometer through an optical coupler. The echo signal (signal light) of the signal arm and the end face reflection signal (reference light) of the reference arm are mixed coherently by the photodetector. Due to the adoption of frequency domain analysis and coherent measurement, Optical Frequency Domain Reflection (OFDR) overcomes the defect of OTDR in distance resolution capability in principle, the distance resolution of the OTDR can be improved by 3 orders of magnitude, and the OFDR-based distributed optical fiber sensing has extremely high distance resolution, avoids average effect, can realize high-sensitivity distributed measurement, and is a new generation of high-precision distributed optical fiber sensing technology acknowledged in the industry.
The low coherent light reflection technology is a low coherent light Michelson interferometry technology, distributed measurement is realized by scanning of a reference arm, the distributed measurement has micrometer-level distance resolution, but is limited by a mechanical scanning range, the measurable distance range is very limited, the distributed measurement is mainly used for optical coherence tomography and detection of optical devices and is not suitable for measurement of optical fiber links and large-scale components, and an optical frequency domain reflectometer is an intelligent high-end device.
The existing optical frequency domain reflection technology has the defects of distance resolution and the optical frequency domain reflection technology in measuring distance.
Disclosure of Invention
The invention aims to provide an optical frequency domain reflectometer based on an industrial all-in-one machine, which aims to solve the problems that the distance resolution of the existing optical frequency domain reflection technology and the distance measurement of the optical frequency domain reflection technology are insufficient in the background technology.
The utility model provides a light frequency domain reflectometer based on industry all-in-one, includes optical fiber, overall control and light frequency domain reflection technology that awaits measuring, the optical fiber electric connection that awaits measuring has circulator and supplementary interferometer, the output electric connection of circulator and supplementary interferometer has difference to absorb and double-balanced absorption, the output electric connection that difference absorbed and double-balanced absorption has analog signal to take care of, the output electric connection that analog signal took care of has nonlinear sweep frequency to rectify and ADC, overall control electric connection has nonlinear sweep frequency to rectify, ADC, laser frequency control and digital signal processing.
Preferably, the output end of the laser frequency control is electrically connected with a narrow-linewidth frequency-sweeping laser.
Preferably, the narrow-linewidth frequency-sweeping laser, the circulator and the auxiliary interferometer are all electrically connected.
Preferably, the overall control and nonlinear sweep frequency correction, ADC, laser frequency control and digital signal processing are all connected in two directions.
Preferably, the overall control is connected with the nonlinear sweep frequency correction, the ADC, the laser frequency control and the digital signal processing through a control bus and a data bus.
Preferably, the optical frequency domain reflection technology is also a measurement technology based on michelson interference, a coherent optical signal with linear frequency scanning is divided into reference light and signal light after passing through a michelson optical fiber interferometer, because of the difference of optical paths, the reference light and the echo signal light have frequency difference, after coherent mixing by a photoelectric detector, the transmission characteristic of the measured optical fiber can be obtained through frequency domain analysis, and then the performance and the fault condition of the measured optical fiber can be measured.
Preferably, a parallel structure is formed between the differential absorption and the double balanced absorption, the differential absorption and the double balanced absorption are independent of each other, a parallel structure is formed between the nonlinear frequency sweep correction and the ADC, and the nonlinear frequency sweep correction and the ADC are independent of each other.
Preferably, the overall control electrical property and the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal processing are all in a series structure, the overall control electrical property is used for controlling the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal, the overall control electrical property processes the signals of the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal, and after the processing, the information is fed back to the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal.
Preferably, the electrical property of the optical fiber to be detected and the electrical property of the circulator and the auxiliary interferometer are in a series structure, and the circulator and the auxiliary interferometer and the differential absorption and double-balanced absorption are in a series structure.
Preferably, the digital signal processing is directly and independently controlled by the overall control, and the digital signal processing and the overall control are electrically connected in a bidirectional mode.
Compared with the prior art, the invention has the following beneficial effects: the optical frequency domain reflectometer based on the industrial all-in-one machine overcomes the defects of OTDR in distance resolution and OLCR in measuring distance in principle, can realize the measurement of high distance resolution, high sensitivity and medium distance, is mainly used for fault detection of a special optical fiber network for medium and short distance, health monitoring of large-scale components, analysis of the coupling process of the optical fiber polarization state and monitoring of the overall control electrical property and nonlinear frequency sweep correction, and the ADC, the laser frequency control and the digital signal processing are of a series structure, the overall control electrical property is used for controlling the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal, the overall control electrical property processes the signals of the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal, and after the processing, the information is fed back to the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal processing, The laser frequency control and the digital signal are connected in series, the overall control electrical property can be smoothly completed to control the nonlinear sweep frequency correction, the ADC, the laser frequency control and the information transmission among the digital signals, the mutual influence among the three is ensured, the normal operation of the reflectometer is ensured, the bidirectional electrical connection is realized between the digital signal processing and the overall control, the control is directly and independently controlled, no complex intermediate program is needed, the control efficiency is improved, the problem of limited resolution during long-distance measurement is solved based on a novel method of closed-loop feedback type laser line width compression and traction type wide-range optical frequency linear scanning, the measurement of millimeter-order distance resolution and kilometer-distance range can be realized, the practical application requirements are met, the laser phase noise and sweep frequency nonlinear compensation technology based on I/Q photolysis and Hilbert conversion enhances the signal-to noise ratio (SNR) of the system, the measurement accuracy of OFDR is improved, the problem of polarization sensitivity in coherent light detection is solved based on a balanced mixing type polarization diversity optical heterodyne coherent detection technology, and the measurement sensitivity in OFDR measurement is improved.
Drawings
FIG. 1 is a system block schematic diagram of an optical frequency domain reflectometer of the present invention;
FIG. 2 is a schematic block diagram of an optical frequency domain reflectometer of the present invention;
FIG. 3 is a measured OFDR curve of the present invention;
FIG. 4 is a schematic diagram of the key performance index of the OFDR prototype of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
An optical frequency domain reflectometer based on an industrial all-in-one machine comprises an optical fiber to be detected, an overall control and optical frequency domain reflection technology, wherein the optical fiber to be detected is electrically connected with a circulator and an auxiliary interferometer, the output ends of the circulator and the auxiliary interferometer are electrically connected with a differential absorption and a double balanced absorption, the output ends of the differential absorption and the double balanced absorption are electrically connected with an analog signal conditioning, the output end of the analog signal conditioning is electrically connected with a nonlinear frequency sweep correction and an ADC, the overall control is electrically connected with a nonlinear frequency sweep correction, the ADC, a laser frequency control and a digital signal processing, the output end of the laser frequency control is electrically connected with a narrow-linewidth frequency sweep laser, the narrow-linewidth frequency sweep laser is electrically connected with the circulator and the auxiliary interferometer, and the overall control is bidirectionally connected with the nonlinear frequency sweep correction, the ADC, the laser, the overall control and nonlinear frequency sweep correction, ADC, laser frequency control and digital signal processing are connected with a data bus through a control bus, an optical frequency domain reflection technology is also a measurement technology based on Michelson interference, a coherent light signal of frequency linear scanning is divided into reference light and signal light through a Michelson optical fiber interferometer, the reference light and echo signal light have frequency difference due to the difference of optical paths, the transmission characteristic of a measured optical fiber can be obtained through frequency domain analysis after coherent mixing of a photoelectric detector, and further the performance and the fault condition of the measured optical fiber can be measured, the differential absorption and the double-balanced absorption are of a parallel structure, the differential absorption and the double-balanced absorption are mutually independent, the nonlinear frequency sweep correction and the ADC are of a parallel structure, the nonlinear frequency sweep correction and the ADC are mutually independent, and the overall control electrical property and the nonlinear frequency sweep correction, The optical fiber electrical property to be detected, the circulator and the auxiliary interferometer are connected in series with the differential absorption and the double balanced absorption, the digital signal processing is directly and independently controlled by the overall control, meanwhile, the digital signal processing and the overall control are electrically connected in two directions, and are directly and independently controlled without complex intermediate programs, and the control efficiency is improved.
In summary, the defects of OTDR in distance resolution and OLCR in measuring distance are overcome in principle, and measurement of high distance resolution, high sensitivity and medium distance can be realized, an optical frequency domain reflectometer based on an industrial all-in-one machine is mainly used for fault detection of a medium-short distance special optical fiber network, health monitoring of a large-scale component and analysis and monitoring of an optical fiber polarization state coupling process, the optical frequency domain reflectometer is used for measuring 500m +1.3km +1km +1.3km optical fibers, and the result of measurement of 500m +1.3km +1m +1.3km optical fibers is shown in fig. 3; according to the actual measurement result, the performance index of the optical frequency domain reflectometer is completed, as shown in fig. 4, the test result shows that the product realizes the positioning precision of 1.5mm and the measurement distance of 500 m; the OFDR measurement with the positioning precision of 3mm and the measurement distance of 2km, the series structure can smoothly complete the overall control electrical property for controlling the nonlinear sweep frequency correction, the ADC, the laser frequency control and the information transmission among digital signals, ensures that the three are not influenced mutually, ensures that a reflectometer normally operates, realizes the bidirectional electrical connection between the digital signal processing and the overall control, directly and independently controls without complex intermediate programs, improves the control efficiency, has obvious innovation in the core technical scheme, has independent intellectual property rights of the core technology, can meet the current application requirements in technical indexes, fills the blank of China, breaks through the exclusive monopoly in foreign countries, is an advanced device which can serve the aspects of aerospace, national defense construction, safe production, shock prevention and disaster reduction and the like, has wide application value and market prospect, and is based on the closed-loop feedback laser line width compression and the traction type wide-range optical frequency linear scanning, the method solves the problem of limited resolution in long-distance measurement, can realize measurement of millimeter-level distance resolution and a distance range of several kilometers, meets the requirement of practical application, enhances the signal-to-noise ratio (SNR) of the system based on the laser phase noise and frequency sweep nonlinear compensation technology of I/Q optical demodulation and Hilbert conversion, improves the measurement precision of OFDR, solves the problem of polarization sensitivity in coherent optical detection based on the balanced frequency mixing type polarization diversity optical heterodyne coherent detection technology, and improves the measurement sensitivity in the OFDR measurement.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.
Claims (10)
1. The utility model provides a light frequency domain reflectometer based on industry all-in-one, includes optical fiber, overall control and light frequency domain reflection technique that awaits measuring, its characterized in that, the optical fiber electric connection that awaits measuring has circulator and supplementary interferometer, the output electric connection of circulator and supplementary interferometer has differential absorption and two balanced absorptions, the output electric connection that differential absorption and two balanced absorptions has analog signal to take care of, the output electric connection that analog signal took care of has nonlinear sweep frequency to rectify and ADC, overall control electric connection has nonlinear sweep frequency to rectify, ADC, laser frequency control and digital signal processing.
2. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the output end of the laser frequency control is electrically connected with a narrow-linewidth frequency-sweeping laser.
3. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: and the narrow-linewidth frequency-sweeping laser, the circulator and the auxiliary interferometer are electrically connected.
4. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the overall control and the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal processing are all in bidirectional connection.
5. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the overall control and the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal processing are connected through a control bus and a data bus.
6. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the optical frequency domain reflection technology is also a measurement technology based on Michelson interference, a coherent light signal with linear frequency scanning is divided into reference light and signal light after passing through a Michelson optical fiber interferometer, because of difference of optical paths, the reference light and echo signal light have frequency difference, after coherent mixing is carried out by a photoelectric detector, the transmission characteristic of the measured optical fiber can be obtained through frequency domain analysis, and then the performance and the fault condition of the measured optical fiber can be measured.
7. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the differential absorption and the double-balanced absorption are in a parallel structure and are independent from each other, and the nonlinear frequency sweep correction and the ADC are in a parallel structure and are independent from each other.
8. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the overall control electrical property is used for controlling the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal, the overall control electrical property processes the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal, and after the processing is finished, information is fed back to the nonlinear frequency sweep correction, the ADC, the laser frequency control and the digital signal.
9. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the electrical property of the optical fiber to be detected, the circulator and the auxiliary interferometer are in a series structure, and the circulator and the auxiliary interferometer, the differential absorption and the double-balanced absorption are in a series structure.
10. The optical frequency domain reflectometer based on an industrial all-in-one machine as claimed in claim 1, wherein: the digital signal processing is directly and independently controlled by the overall control, and meanwhile, the digital signal processing and the overall control are electrically connected in a bidirectional mode.
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2019
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Patent Citations (7)
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| CN102946270A (en) * | 2011-09-27 | 2013-02-27 | 中华电信股份有限公司 | Optical frequency domain reflection type optical fiber network testing method |
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