CN111397851A - OFDR multi-path optical fiber sensing system and method based on optical frequency comb technology - Google Patents
OFDR multi-path optical fiber sensing system and method based on optical frequency comb technology Download PDFInfo
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Abstract
The invention discloses an OFDR multi-path optical fiber sensing system and method based on an optical frequency comb technology, which comprises the following steps: the device comprises an optical frequency comb laser, a frequency sweep generator, a single-side band modulator, an auxiliary interferometer, a main interferometer, a data acquisition card and a data processor; the single-sideband modulator is used for receiving a pulse optical signal with a frequency spectrum of a discrete spectral line generated by the optical frequency comb laser and a linear frequency sweep electric signal output by the frequency sweep generator, and modulating the pulse optical signal and the linear frequency sweep electric signal into a composite frequency sweep signal with multiple wavelengths and frequency sweep simultaneously; the auxiliary interferometer is used for receiving the composite frequency sweep signal of the multi-wavelength simultaneous frequency sweep and then generating an external clock signal; the main interferometer is used for receiving the composite sweep frequency signal of multi-wavelength simultaneous sweep frequency and then generating a beat frequency interference signal; and the data processor processes the external clock signal and the beat frequency interference signal received by the data acquisition card to obtain the simultaneous measurement result of the multiple sections of optical fibers. The spatial resolution and the sensing efficiency of the sensing system are improved.
Description
Technical Field
The invention belongs to the field of optical fiber sensing, and relates to an OFDR multi-path optical fiber sensing system and method based on an optical frequency comb technology.
Background
An Optical Frequency Domain Reflectometer (OFDR) is a distributed optical fiber sensor with high spatial resolution, high sensing sensitivity and high positioning accuracy. Has great application prospect in the fields of aerospace, precision instrument manufacturing, building monitoring and the like. In the basic structure of constructing the optical frequency domain reflectometer, a tunable laser is a very important ring, the performance of the tunable laser also has great influence on various parameter indexes of the whole system, and in order to ensure the quality of sensing parameters of the OFDR system, the tunable laser with good sweep frequency linearity, narrow line width, large scanning range and high scanning speed must be selected. However, such high performance tunable laser has low output power, cannot meet the requirement of simultaneously measuring multiple optical fibers, and is very expensive, so that the cost of the OFDR sensing system is high.
Disclosure of Invention
In view of the above problems, the present invention provides an OFDR multi-path optical fiber sensing system based on optical frequency comb technology, so as to solve one of the above technical problems.
According to a first embodiment of the present invention, the OFDR multi-path optical fiber sensing system based on optical frequency comb technology includes:
the device comprises an optical frequency comb laser, a frequency sweep generator, a single-side band modulator, an auxiliary interferometer, a main interferometer, a data acquisition card and a data processor; wherein,
the optical frequency comb laser is used for generating a pulse optical signal with a frequency spectrum of a discrete spectral line;
the sweep generator is used for outputting an electric signal and a trigger signal of linear sweep;
the single-sideband modulator is used for receiving the pulse light signal with the frequency spectrum of discrete spectral lines generated by the optical frequency comb laser and the linear frequency sweep electric signal output by the frequency sweep generator, and modulating the pulse light signal with the frequency spectrum of discrete spectral lines generated by the optical frequency comb laser and the linear frequency sweep electric signal output by the frequency sweep generator into a composite frequency sweep signal with multiple wavelengths and frequency sweep simultaneously;
the auxiliary interferometer is used for receiving the composite frequency sweeping signal of the multi-wavelength simultaneous frequency sweeping to generate an external clock signal;
the main interferometer is arranged in parallel with the auxiliary interferometer and is used for receiving the composite sweep frequency signal of the multi-wavelength simultaneous sweep frequency and then generating beat frequency interference signals;
the data acquisition card receives the external clock signal and the beat frequency interference signal under the control of the trigger signal;
and the data processor is used for processing the external clock signal and the beat frequency interference signal received by the data acquisition card to obtain the simultaneous measurement result of the multiple sections of optical fibers.
Preferably, the main interferometer comprises N interference branches, where N is a natural number greater than or equal to 2;
wherein each interference branch comprises a fourth optical fiber coupler c4, a fifth optical fiber coupler c5, a polarization controller, a circulator, a test optical fiber and a photodetector.
Preferably, each of the N interference branches is divided into two paths by the fourth fiber coupler c4, and includes:
the first path comprises the fourth optical fiber coupler c4, the polarization controller and the fifth optical fiber coupler c5 which are connected in sequence; the second path comprises the fourth optical fiber coupler c4, a circulator, a test optical fiber and the fifth optical fiber coupler c5 which are connected in sequence; wherein there is an optical path difference between the fourth fiber coupler c4 and the fifth fiber coupler c 5.
Preferably, the auxiliary interferometer comprises: a second fiber coupler c2, a third fiber coupler c3 and a photodetector;
the second optical fiber coupler c2 and the third optical fiber coupler c3 are coupled with two different optical fiber lengths respectively and then are connected with the photodetector in sequence, and an arm path difference exists between the second optical fiber coupler c2 and the third optical fiber coupler c 3.
Preferably, the frequency range Δ f corresponding to the wavelength is 0 to 1000 GHZ.
Preferably, the optical path difference is 0-50 m.
Preferably, the arm path difference is more than twice of the optical path difference of the main interferometer.
Preferably, the method further comprises the following steps:
the arrayed waveguide grating is connected with the other end of the fourth optical fiber coupler c4, and the main interferometer is divided into N interference branches through the arrayed waveguide grating.
Preferably, the method further comprises the following steps:
and one end of the first optical fiber coupler c1 is connected with the single-sideband modulator, and the other end of the first optical fiber coupler c1 is respectively connected with the main interferometer and the auxiliary interferometer, and is used for splitting the composite swept frequency signal of the multi-wavelength simultaneous sweeping frequency to the auxiliary interferometer and the main interferometer.
Based on the same inventive idea, the present invention further provides a method for multi-channel fiber sensing using the system of any one of claims 1 to 9, comprising:
the optical frequency comb laser generates a pulse optical signal with a frequency spectrum of discrete spectral lines;
the sweep generator sends out an electric signal of linear sweep;
inputting a pulse optical signal with a frequency spectrum of a discrete spectral line generated by the optical frequency comb laser and an electric signal of linear sweep frequency output by the sweep frequency generator into a single-sideband modulator;
inputting the output swept-frequency light with a plurality of wavelengths swept simultaneously, which is modulated by the single-sideband modulator, into a first optical fiber coupler c 1;
dividing swept-frequency light with multiple wavelengths swept simultaneously in the first optical fiber coupler c1 into two paths, wherein the first path enters a second optical fiber coupler c2 and a third optical fiber coupler c3 in the auxiliary interferometer, and optical path difference occurs after coupling of two different optical fiber lengths through the second optical fiber coupler c2 and the third optical fiber coupler c3 to form an external clock signal, and the external clock signal enters a photoelectric detector;
the second path enters the main interferometer, passes through the arrayed waveguide grating, and is divided into N paths of sweep frequency optical signals with different wavelength ranges, wherein the sweep frequency optical signals are divided into two paths in the main interferometer by an optical fiber coupler c4, one path passes through the polarization controller and a fifth optical fiber coupler c5, the other path enters an optical fiber to be detected through a circulator and then returns to the fifth optical fiber coupler c5, and optical path differences occur in the two paths to form beat frequency interference signals which are input to the photoelectric detector;
the photoelectric detector converts the external clock signal and the beat frequency interference signal into electric signals, and the electric signals are accessed into a data acquisition card to finish the acquisition of the signals;
and the data processor receives the electric signals output by the data acquisition card and obtains the simultaneous measurement results of the multiple sections of optical fibers after processing.
The invention has the advantages of
The invention combines optical frequency comb technology with optical frequency domain reflection technology. The optical frequency comb laser is used as a signal source, continuous light containing a multi-wavelength range simultaneous linear frequency sweeping signal is generated by signal modulation with a frequency sweeping signal generator, and the composite linear frequency sweeping light is used as a frequency sweeping light source of the optical frequency domain reflectometer. And separating the sweep light in the multi-wavelength range into a plurality of beams of sweep light, and respectively inputting the sweep light in different wave bands into a plurality of optical fibers to be tested for sensing test.
In the structure of the optical frequency domain reflectometer, the sweep-frequency light in a multi-wavelength range is separated into a plurality of beams of sweep-frequency light by the wavelength division multiplexing technology.
The invention fully utilizes the sensing structure of the optical frequency domain reflector to improve the spatial resolution and the sensing precision of the sensing system, improves the sensing efficiency of the optical frequency domain reflector and reduces the cost for detecting the multi-section optical fiber by utilizing the optical frequency domain reflector.
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In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic diagram of an OFDR multi-path optical fiber sensing system based on an optical frequency comb technique according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an OFDR multi-path distributed optical fiber sensing principle in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
As shown in fig. 1, according to the first embodiment of the present invention, the optical frequency comb laser generates a signal source with multiple wavelengths and frequency sweep signals superimposed, so as to solve the problem of power limitation when a tunable laser is directly used for detection, thereby increasing the number of sensing fibers accessed by the OFDR system, and expanding the applicable scenarios of the OFDR system.
The invention discloses a schematic diagram of an OFDR multi-path optical fiber sensing system based on an optical frequency comb technology, as shown in figure 1, the whole OFDR system consists of an optical frequency comb laser, a frequency sweep generator, a single-sideband modulator, an auxiliary interferometer, a main interferometer and a data acquisition module, wherein the auxiliary interferometer and the main interferometer both use Mach-Zehnder interferometers.
The optical frequency comb laser generates pulse light with frequency spectrum of equal frequency interval delta f being 1000GHZ and discrete spectral line, the sweep frequency generator sends out electric signal and trigger signal with frequency delta f being 1000GHZ linear sweep frequency, the sweep frequency range is equal to the spectral line interval of the output signal of the optical frequency comb, and the two paths of signals generate sweep frequency light with multi-section wavelength and sweep frequency simultaneously after being modulated by a single side band. Wherein the trigger signal controls the opening and closing time of the acquired data.
The swept-frequency light output from the single-sideband modulator enters an OFDR optical path and is divided into two paths by a coupler c1, wherein one path enters an auxiliary interferometer to generate an external clock signal for the data acquisition module to assist signal acquisition, and the other path enters a main interferometer to generate a beat-frequency interference signal to be acquired by the data acquisition module finally. The main interferometer and the auxiliary interferometer are arranged in parallel, one end of a coupler c1 is connected with the single-sideband modulator, the other end of the coupler c1 is connected with the main interferometer and the auxiliary interferometer respectively, and the composite swept-frequency signal with the multiple wavelengths swept simultaneously is shunted to the auxiliary interferometer and the main interferometer.
The main interferometer is divided into N interference branches by the arrayed waveguide grating, where N is a natural number greater than or equal to 2, and this embodiment is described by taking N as an example 2.
Each of the N interference branches includes a fourth fiber coupler c4, a fifth fiber coupler c5, a polarization controller, a circulator, a test fiber, and a photodetector. The polarization controller is divided into two paths through a coupler c4, wherein one path comprises an optical fiber coupler c4, a polarization controller and an optical fiber coupler c5 which are sequentially connected; the other path comprises a fiber coupler c4, a circulator, a test fiber and a fiber coupler c5 which are connected in sequence; wherein, the optical path difference between the optical fiber coupler c4 and the optical fiber coupler c5 is 0-50 m. The sweep frequency light enters the main interferometer and is divided into two paths by the optical fiber coupler c4, one path of light enters the testing optical fiber through the circulator, the sweep frequency light is transmitted in the optical fiber to be tested to generate a backward Rayleigh scattering signal opposite to the propagation direction, the signal returns through the circulator, beat frequency interference is generated on the optical fiber coupler c5 with the other path of optical signal passing through the polarization controller, and the generated beat frequency interference signal is input into the photoelectric detector and is collected by the collecting card after being converted into an electric signal.
An auxiliary interferometer comprising: a fiber coupler c2, a fiber coupler c3 and a photodetector; the optical fiber coupler c2 and the optical fiber coupler c3 are connected with two different optical fiber lengths respectively and then connected with the photoelectric detector, arm path difference between the optical fiber coupler c2 and the optical fiber coupler c3 is more than twice of optical path difference of the main interferometer, and the beat frequency signal frequency generated by the auxiliary interferometer is more than twice of the beat frequency signal frequency generated by the main interferometer, so that the Nyquist sampling theorem is met, and the acquired signals are guaranteed not to be distorted.
One end of the data acquisition card is connected with the photoelectric detector, the other end of the data acquisition card is connected with the data processor, the data acquisition card receives the electric signals output by the photoelectric detector, and the electric signals are processed by the data processor to obtain simultaneous measurement results of the multiple sections of optical fibers.
The invention combines optical frequency comb technology with optical frequency domain reflection technology. The optical frequency comb laser is used as a signal source, continuous light containing a multi-wavelength range simultaneous linear frequency sweeping signal is generated by signal modulation with a frequency sweeping signal generator, and the composite linear frequency sweeping light is used as a frequency sweeping light source of the optical frequency domain reflectometer. And separating the sweep light in the multi-wavelength range into a plurality of beams of sweep light, and respectively inputting the sweep light in different wave bands into a plurality of optical fibers to be tested for sensing test.
In the structure of the optical frequency domain reflectometer, the sweep-frequency light in a multi-wavelength range is separated into a plurality of beams of sweep-frequency light by the wavelength division multiplexing technology.
The invention fully utilizes the sensing structure of the optical frequency domain reflector to improve the spatial resolution and the sensing precision of the sensing system, improves the sensing efficiency of the optical frequency domain reflector and reduces the cost for detecting the multi-section optical fiber by utilizing the optical frequency domain reflector.
As shown in fig. 2, according to a second embodiment of the present invention, the present invention provides an OFDR multi-path optical fiber sensing method based on an optical frequency comb technique.
Fig. 2 is a schematic diagram of an OFDR multi-path distributed optical fiber sensing principle based on an optical frequency comb technology, in which a system structure and a signal waveform are described in detail, an optical frequency comb laser emits a pulse sequence light with an equal frequency interval Δ f of 1000GHZ between every two vertical lines, a sweep generator emits a linear sweep signal with a triangular period of T1 and a frequency Δ f of 1000GHZ, and the linear sweep signal and the sweep signal are modulated into a composite sweep signal with a multi-wavelength and a swept period of Δ T by a single-sideband modulator by using an electric energy and bandwidth amplitude modulation technology. The composite sweep frequency signal is divided into two paths through the optical fiber coupler c1, one path enters the auxiliary interferometer, and because the couplers c2 and c3 are connected by different optical fiber lengths, the two paths of optical fibers have arm path difference which is usually more than twice of the optical path difference of the main interferometer, beat frequency interference occurs on the optical signal at the coupler c3, beat frequency interference signals carrying light source phase information, namely external clock signals, are generated, and are converted into electric signals through the photoelectric detector PD and then are input into the acquisition card as an acquisition card clock.
Arrayed waveguide gratings are commonly used in optical multiplexers in wavelength division multiplexed WDM systems to combine light of many wavelengths into a single optical fiber, thereby increasing the propagation efficiency of the fiber optic network. The other path of the array waveguide grating AWG passes through the array waveguide grating AWG and is divided into N paths of sweep light with different wavelength ranges, and the wavelength sweep range is delta f which is 1000 GHZ. Each path of signal is input into a built main interferometer with mutually independent paths. Taking one path of main interferometer shown in the figure as an example, a signal is divided into two paths by a coupler c4 in the independent main interferometer, one path of the signal passes through a polarization controller as a reference arm and then enters a coupler c5, the other path of the signal passes through a circulator as a signal arm and enters an optical fiber to be tested, and then the signal returns to the circulator from the optical fiber to be tested and then enters a coupler c 5. An optical path difference exists between the backward rayleigh scattering signal in the signal arm and the optical signal in the reference arm, the optical path difference is the length of the sensing optical fiber, and is usually 0-50m, so that the frequencies of the optical signals carried by the two paths of signals are different, and beat frequency interference occurs in the coupler c 5. The beat frequency signal is input into the photoelectric detector to convert the interference optical signal into an electric signal, and the electric signal is acquired by the data acquisition card.
In addition, the working state of the data acquisition card is controlled by another square wave TT L trigger signal with the period of t1 sent by the sweep frequency generator, the signal is a direct current signal and is used for controlling the time point when the acquisition card starts to acquire and finishes acquiring, so that each path of beat frequency interference signal is acquired synchronously, when the time point is 0-t1, the trigger signal can control the acquisition card to be started to enable the acquisition card to be in the working state of acquiring data, when the time point is t1-t2, the trigger signal can control the acquisition card to be closed to enable the acquisition card to be in the state of not acquiring data, and when the time point is t3-t4, the trigger signal can control the acquisition card to be started to enable the acquisition card to be in the working state of acquiring.
And generating power spectrum information of the acquired signals through the data processor, wherein the power spectrum information reflects the signal reflection intensity in the whole section of the measuring optical fiber, and obtaining the simultaneous measuring results of the plurality of sections of the optical fibers.
The invention combines optical frequency comb technology with optical frequency domain reflection technology. The optical frequency comb laser is used as a signal source, continuous light containing a multi-wavelength range simultaneous linear frequency sweeping signal is generated by signal modulation with a frequency sweeping signal generator, and the composite linear frequency sweeping light is used as a frequency sweeping light source of the optical frequency domain reflectometer. And separating the sweep light in the multi-wavelength range into a plurality of beams of sweep light, and respectively inputting the sweep light in different wave bands into a plurality of optical fibers to be tested for sensing test.
In the structure of the optical frequency domain reflectometer, the sweep-frequency light in a multi-wavelength range is separated into a plurality of beams of sweep-frequency light by the wavelength division multiplexing technology.
The invention fully utilizes the sensing structure of the optical frequency domain reflector to improve the spatial resolution and the sensing precision of the sensing system, improves the sensing efficiency of the optical frequency domain reflector and reduces the cost for detecting the multi-section optical fiber by utilizing the optical frequency domain reflector.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. An OFDR multi-path optical fiber sensing system based on an optical frequency comb technology is characterized by comprising:
the device comprises an optical frequency comb laser, a frequency sweep generator, a single-side band modulator, an auxiliary interferometer, a main interferometer, a data acquisition card and a data processor; wherein,
the optical frequency comb laser is used for generating a pulse optical signal with a frequency spectrum of a discrete spectral line;
the sweep generator is used for outputting an electric signal and a trigger signal of linear sweep;
the single-sideband modulator is used for receiving the pulse light signal with the frequency spectrum of discrete spectral lines generated by the optical frequency comb laser and the linear frequency sweep electric signal output by the frequency sweep generator, and modulating the pulse light signal with the frequency spectrum of discrete spectral lines generated by the optical frequency comb laser and the linear frequency sweep electric signal output by the frequency sweep generator into a composite frequency sweep signal with multiple wavelengths and frequency sweep simultaneously;
the auxiliary interferometer is used for receiving the composite frequency sweeping signal of the multi-wavelength simultaneous frequency sweeping to generate an external clock signal;
the main interferometer is arranged in parallel with the auxiliary interferometer and is used for receiving the composite sweep frequency signal of the multi-wavelength simultaneous sweep frequency and then generating beat frequency interference signals;
the data acquisition card receives the external clock signal and the beat frequency interference signal under the control of the trigger signal;
and the data processor is used for processing the external clock signal and the beat frequency interference signal received by the data acquisition card to obtain the simultaneous measurement result of the multiple sections of optical fibers.
2. The OFDR multi-path optical fiber sensing system based on the optical frequency comb technology of claim 1, wherein the main interferometer comprises N interference branches, wherein N is a natural number greater than or equal to 2;
wherein each interference branch comprises a fourth optical fiber coupler c4, a fifth optical fiber coupler c5, a polarization controller, a circulator, a test optical fiber and a photodetector.
3. The OFDR multi-path optical fiber sensing system based on optical-frequency comb technology of claim 2, wherein each of said N interference branches is divided into two paths by said fourth optical fiber coupler c4, comprising:
the first path comprises the fourth optical fiber coupler c4, the polarization controller and the fifth optical fiber coupler c5 which are connected in sequence; the second path comprises the fourth optical fiber coupler c4, a circulator, a test optical fiber and the fifth optical fiber coupler c5 which are connected in sequence; wherein there is an optical path difference between the fourth fiber coupler c4 and the fifth fiber coupler c 5.
4. The OFDR multi-path fiber sensing system based on optical-frequency comb technology of claim 1, wherein said auxiliary interferometer comprises:
a second fiber coupler c2, a third fiber coupler c3 and a photodetector;
the second optical fiber coupler c2 and the third optical fiber coupler c3 are coupled with two different optical fiber lengths respectively and then are connected with the photodetector in sequence, and an arm path difference exists between the second optical fiber coupler c2 and the third optical fiber coupler c 3.
5. The OFDR multi-path fiber sensing system based on optical-frequency combing technology of claim 1, wherein the wavelength corresponds to a frequency range Δ f of 0-1000 GHZ.
6. The OFDR multi-path fiber sensing system based on optical-frequency comb technology of claim 3, wherein the optical path difference is 0-50 m.
7. The OFDR multi-path fiber sensing system based on optical-frequency comb technology of claim 4, wherein the arm path difference is more than twice as large as the main interferometer.
8. The OFDR multi-path fiber sensing system based on optical-frequency comb technology of claim 2, further comprising:
the arrayed waveguide grating is connected with the other end of the fourth optical fiber coupler c4, and the main interferometer is divided into N interference branches through the arrayed waveguide grating.
9. The OFDR multi-path fiber sensing system based on optical-frequency comb technology of claim 1, further comprising:
and one end of the first optical fiber coupler c1 is connected with the single-sideband modulator, and the other end of the first optical fiber coupler c1 is respectively connected with the main interferometer and the auxiliary interferometer, and is used for splitting the composite swept frequency signal of the multi-wavelength simultaneous sweeping frequency to the auxiliary interferometer and the main interferometer.
10. A method for multiplexed fiber optic sensing using the system of any of claims 1-9, comprising:
the optical frequency comb laser generates a pulse optical signal with a frequency spectrum of discrete spectral lines;
the sweep generator sends out an electric signal of linear sweep;
inputting a pulse optical signal with a frequency spectrum of a discrete spectral line generated by the optical frequency comb laser and an electric signal of linear sweep frequency output by the sweep frequency generator into a single-sideband modulator;
inputting the output swept-frequency light with a plurality of wavelengths swept simultaneously, which is modulated by the single-sideband modulator, into a first optical fiber coupler c 1;
dividing swept-frequency light with multiple wavelengths swept simultaneously in the first optical fiber coupler c1 into two paths, wherein the first path enters a second optical fiber coupler c2 and a third optical fiber coupler c3 in the auxiliary interferometer, and optical path difference occurs after coupling of two different optical fiber lengths through the second optical fiber coupler c2 and the third optical fiber coupler c3 to form an external clock signal, and the external clock signal enters a photoelectric detector;
the second path enters the main interferometer, passes through the arrayed waveguide grating, and is divided into N paths of sweep frequency optical signals with different wavelength ranges, wherein the sweep frequency optical signals are divided into two paths in the main interferometer by an optical fiber coupler c4, one path passes through the polarization controller and a fifth optical fiber coupler c5, the other path enters an optical fiber to be detected through a circulator and then returns to the fifth optical fiber coupler c5, and optical path differences occur in the two paths to form beat frequency interference signals which are input to the photoelectric detector;
the photoelectric detector converts the external clock signal and the beat frequency interference signal into electric signals, and the electric signals are accessed into a data acquisition card to finish the acquisition of the signals;
and the data processor receives the electric signals output by the data acquisition card and obtains the simultaneous measurement results of the multiple sections of optical fibers after processing.
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| CN112762970A (en) * | 2021-03-09 | 2021-05-07 | 冉曾令 | High-performance distributed optical fiber sensing system and method |
| CN113804303A (en) * | 2021-08-16 | 2021-12-17 | 广东工业大学 | Distributed bidirectional polarization measuring device based on double beat frequency single auxiliary interferometer |
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| CN112129332A (en) * | 2020-08-20 | 2020-12-25 | 山东航天电子技术研究所 | Flexible multiplexing device of large-scale fiber grating sensor based on OFDR |
| CN112762970A (en) * | 2021-03-09 | 2021-05-07 | 冉曾令 | High-performance distributed optical fiber sensing system and method |
| CN113804303A (en) * | 2021-08-16 | 2021-12-17 | 广东工业大学 | Distributed bidirectional polarization measuring device based on double beat frequency single auxiliary interferometer |
| CN113804303B (en) * | 2021-08-16 | 2023-12-26 | 广东工业大学 | Distributed bidirectional polarization measuring device based on double beat frequency single auxiliary interferometer |
| CN113940631A (en) * | 2021-10-18 | 2022-01-18 | 中国科学院长春光学精密机械与物理研究所 | Optical coherence tomography system |
| WO2023170821A1 (en) * | 2022-03-09 | 2023-09-14 | 日本電信電話株式会社 | Device and method for measuring loss of plurality of optical fibers at once |
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