CN114111861B - BOTDA system, control method and storage medium - Google Patents

BOTDA system, control method and storage medium Download PDF

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Publication number
CN114111861B
CN114111861B CN202210083265.7A CN202210083265A CN114111861B CN 114111861 B CN114111861 B CN 114111861B CN 202210083265 A CN202210083265 A CN 202210083265A CN 114111861 B CN114111861 B CN 114111861B
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optical
unit
continuous
fbg
signal
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CN114111861A (en
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朱晓非
张超
陈科新
姜明武
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Suzhou Guangge Technology Co Ltd
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Suzhou Guangge Technology Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
    • G01D5/35354—Sensor working in reflection
    • G01D5/35358—Sensor working in reflection using backscattering to detect the measured quantity
    • G01D5/35364—Sensor working in reflection using backscattering to detect the measured quantity using inelastic backscattering to detect the measured quantity, e.g. using Brillouin or Raman backscattering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
    • G01D5/35309—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer
    • G01D5/35316—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer using a Bragg gratings

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Optical Communication System (AREA)

Abstract

The invention discloses a BOTDA system, a control method and a storage medium, wherein the BOTDA system comprises: the coupling unit is used for receiving the continuous optical signal and coupling the continuous optical signal into a continuous optical test signal and a continuous optical working signal; the optical switch unit is connected with the coupling unit; the FBG processing module is connected with the optical switch unit and at least used for filtering the received continuous optical test signal and reading the test optical power value of the filtered continuous optical test signal; a control module connected with the FBG processing module and configured to: acquiring an initial optical power value and a test optical power value of a continuous optical test signal; and comparing the absolute value of the difference value between the initial optical power value and the test optical power value with a preset optical power threshold, and controlling the FBG processing module to adjust the temperature when the absolute value of the difference value is greater than the preset optical power threshold until the absolute value of the difference value is less than or equal to the preset optical power threshold, so that the filtering effect of the continuous optical working signal passing through the external sensing optical fiber is improved.

Description

BOTDA system, control method and storage medium
Technical Field
The invention relates to the technical field of optical fibers, in particular to a BOTDA system, a control method and a storage medium.
Background
The distributed optical fiber sensing technology provides a technical means for distributed online monitoring of physical quantities such as temperature, strain, vibration and the like in a long-distance severe environment. A distributed Brillouin Optical fiber temperature/strain sensing system adopting Brillouin Optical Time Domain Analysis (BOTDA) technology is one of the mainstream technical means at home and abroad at present for monitoring the temperature/strain along a long-distance Optical cable.
In the specific application of the loss-type BOTDA, under the action of Stimulated Brillouin Scattering (SBS), the anti-Stokes sideband power of continuous light is transferred to pulse light, and the SBS action can be demodulated by detecting the anti-Stokes sideband power. Filtering with Fiber Bragg Grating (FBG), filtering out spectral components except the anti-Stokes sideband, and sending into a photoelectric detector to detect the spectral power of the anti-Stokes sideband.
Because the FBG is a strain/temperature sensitive device, after the BOTDA is operated for a long time, it is found that the optical center wavelength of the FBG has a drift phenomenon even if the FBG is under the same temperature setting. Whether FBG center wavelength drifts is detected to the tradition with the spectrum appearance, only is applicable to the laboratory environment and sets up the FBG temperature before equipment leaves the factory. However, the spectrometer has a large volume, high equipment price and severe requirements on the use environment, and is difficult to use in the external severe environment.
Disclosure of Invention
Based on this, it is necessary to provide a BOTDA system, a control method, and a storage medium for solving the above-mentioned problems in the background art, to modify the internal optical path structure of the existing BOTDA system, to implement automatic correction of the FBG center wavelength, to improve the filtering effect, without requiring professional testing equipment such as a spectrometer, to reduce the engineering debugging difficulty, to improve the engineering practicability of the BOTDA system, and to prolong the maintenance period.
In order to solve the above technical problem, a first aspect of the present application provides a BOTDA system, including:
the coupling unit is used for receiving the continuous optical signal and coupling the continuous optical signal into a continuous optical test signal and a continuous optical working signal;
an optical switch unit connected with the coupling unit;
the FBG processing module is connected with the optical switch unit and at least used for filtering the received continuous optical test signal and reading a test optical power value of the filtered continuous optical test signal;
a control module connected with the FBG processing module and configured to:
acquiring an initial optical power value and the test optical power value of the continuous optical test signal;
and comparing the absolute value of the difference value between the initial optical power value and the test optical power value with a preset optical power threshold, and controlling the FBG processing module to adjust the temperature when the absolute value of the difference value is greater than the preset optical power threshold until the absolute value of the difference value is less than or equal to the preset optical power threshold.
In the BOTDA system provided in the above embodiment, the coupling unit couples the continuous optical signal into two paths, i.e., a continuous optical test signal and a continuous optical working signal, at a preset splitting ratio, where the continuous optical test signal enters the FBG processing module through one path of the optical switch unit, and the FBG processing module performs filtering processing and detects a test optical power value of the filtered continuous optical test signal; the control module compares the absolute value of the difference value between the initial optical power value and the test optical power value with a preset optical power threshold value, and controls the FBG processing module to adjust the temperature when the absolute value of the difference value is greater than the preset optical power threshold value until the absolute value of the difference value is less than or equal to the preset optical power threshold value, so that the automatic adjustment of the central wavelength of the FBG is completed, and the filtering effect of a continuous optical working signal passing through the external sensing optical fiber is improved. Professional test equipment such as a spectrometer is not needed, the central wavelength of the FBG is automatically adjusted, the engineering debugging difficulty is reduced, the engineering practicability of the BOTDA system is improved, and the maintenance period of the BOTDA system is prolonged.
In one embodiment, the control module is further configured to: the BOTDA system debugging device is connected with the control end of the optical switch unit and controls the first optical input end of the optical switch unit to be opened and the second optical input end of the optical switch unit to be closed when the BOTDA system is debugged; or
When the BOTDA system normally operates, the first optical input end of the optical switch unit is controlled to be switched off and the second optical input end of the optical switch unit is controlled to be switched on, so that continuous optical working signals through the external sensing optical fiber are input to the FBG processing module.
The utility model provides a BOTDA system, accessible light switch unit freely switches BOTDA system debugging and two kinds of modes of BOTDA system normal operating, sets up regularly or untimely automatically regulated according to using on-the-spot actual need, realizes the function of periodic maintenance.
In one embodiment, the BOTDA system further comprises:
a first ring unit configured to: the second end is connected with the coupling unit through an external sensing optical fiber, and the third end is connected with the second optical input end of the optical switch unit.
In one embodiment, the BOTDA system further comprises:
a BOTDA continuous light output configured to: the input end of the coupling unit is connected with the optical fiber for providing the continuous optical signal to the coupling unit;
a BOTDA pulsed light output configured to: and the first end of the first annular unit is connected with the first end of the first annular unit and is used for providing pulsed light signals for the first annular unit.
In one embodiment, the BOTDA system further comprises:
a continuous light output flange configured to: the first end is connected with the coupling unit, and the second end is connected with an external sensing optical fiber;
a pulsed light output flange configured to: the first end is connected with the second end of the first annular unit, and the second end is connected with an external sensing optical fiber.
In one embodiment, the BOTDA system further comprises:
a second ring unit configured to: the first end with the photoswitch unit's optical output end is connected, the second end and the third end all with FBG handles the module connection.
In one embodiment, the FBG processing module comprises:
an FBG unit configured to: the first end of the second annular unit is connected with the second end of the second annular unit and is used for filtering and processing the continuous optical test signal and the continuous optical working signal which is externally connected with a sensing optical fiber;
an FBG temperature control unit configured to: the first end is connected with the second end of the FBG unit, the second end is connected with the control module, and the temperature of the FBG unit is adjusted according to the control module;
a photodetecting unit configured to: the first end of the second annular unit is connected with the third end of the second annular unit, the second end of the second annular unit is connected with the control module, and the second end of the second annular unit is used for reading the test optical power value of the filtered continuous optical test signal and the power value of the continuous optical working signal which is externally connected with the sensing optical fiber.
A second aspect of the present application provides a BOTDA system control method, which is applied to a BOTDA system, where the BOTDA system includes a coupling unit, an optical switch unit, an FBG processing module, and a control module; wherein the control method comprises the following steps:
controlling the coupling unit to couple the continuous optical signal into a continuous optical test signal and a continuous optical working signal;
controlling the FBG processing module to filter the continuous optical test signal and reading a test optical power value of the filtered continuous optical test signal;
and controlling the control module to compare the absolute value of the difference value between the initial optical power value and the test optical power value with a preset optical power threshold value, and controlling the FBG processing module to adjust the temperature when the absolute value of the difference value is greater than the preset optical power threshold value until the absolute value of the difference value is less than or equal to the preset optical power threshold value.
In one embodiment, the control method further comprises:
when the BOTDA system is debugged, the control module controls a first optical input end of the optical switch unit to be opened and a second optical input end of the optical switch unit to be closed; or
When the BOTDA system normally operates, the control module controls the first optical input end of the optical switch unit to be switched off and the second optical input end of the optical switch unit to be switched on, so that continuous optical working signals of external sensing optical fibers are input to the FBG processing module.
A third aspect of the present application proposes a storage medium having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method as described above.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain drawings of other embodiments based on these drawings without any creative effort.
Fig. 1 is a schematic structural diagram of a BOTDA system provided in an embodiment of the present application;
fig. 2 is a schematic structural diagram of a BOTDA system provided in another embodiment of the present application;
fig. 3 is a schematic structural diagram of a BOTDA system provided in another embodiment of the present application;
FIG. 4 is a schematic spectral diagram of a continuous optical test signal provided in an embodiment of the present application;
FIG. 5 is a spectral diagram of a standard filter window of a continuous optical test signal provided in an embodiment of the present application;
FIG. 6 is a spectral diagram illustrating a right shift of a filter window of a filtered continuous optical test signal according to an embodiment of the present application;
FIG. 7 is a spectral diagram illustrating a left shift of a filter window of a filtered continuous optical test signal provided in an embodiment of the present application;
fig. 8 is a flowchart illustrating a BOTDA system control method according to an embodiment of the present application.
Description of reference numerals: 10. a coupling unit; 20. an optical switch unit; 30. an FBG processing module; 31. an FBG unit; 32. an FBG temperature control unit; 33. a photodetecting unit; 40. a control module; 50. a first ring unit; 60. a second ring unit.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are shown in the drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Where the terms "comprising," "having," and "including" are used herein, another element may be added unless an explicit limitation is used, such as "only," "consisting of … …," etc. Unless mentioned to the contrary, terms in the singular may include the plural and are not to be construed as being one in number.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present application.
In this application, unless otherwise expressly stated or limited, the terms "connected" and "connecting" are used broadly and encompass, for example, direct connection, indirect connection via an intermediary, communication between two elements, or interaction between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
After the BOTDA system is operated for a long time, the central wavelength of the FBG drifts, which has the following reasons: 1. the state of the FBG itself changes; 2. due to the fact that the FBG is sensitive to strain, the FBG can be affected by strain after the FBG packaging structural part is affected by long-term vibration and other environments of an industrial field; 3. the FBGs are fixed in the package structure by using an adhesive, and the adhesive changes its shape after long-term operation, thereby squeezing the FBGs.
In the long-distance submarine cable monitoring of offshore wind power and offshore drilling platforms, the BOTDA equipment is placed on the offshore drilling platforms, but the spectrometer is large in size, high in equipment price and strict in requirements on the use environment, and the BOTDA equipment is inconvenient to transport to industrial sites such as offshore platforms and the like regardless of personnel, special equipment such as the spectrometer and the like. If the BOTDA equipment is taken back from the industrial field and returned to the factory for maintenance, a large amount of time is spent, the normal work of the BOTDA equipment on the industrial field is influenced, and relatively more labor, material and time costs are invested.
Therefore, in order to deal with the situation that the industrial site without a spectrometer is used, the BDTDA system and the control method are provided, the internal light path structure of the existing BOTDA system is modified, the FBG central wavelength is automatically corrected, the filtering effect is improved, professional testing equipment such as the spectrometer is not needed, the engineering debugging difficulty is reduced, the engineering practicability of the BOTDA system is improved, and the maintenance period of the BDTDA system is prolonged.
In order to explain the technical solution of the present application, the following description will be given by way of specific examples.
In a BOTDA system provided in an embodiment of the present application, as shown in fig. 1, the BOTDA system includes a coupling unit 10, an optical switching unit 20, an FBG processing module 30, and a control module 40. The optical switch unit 20 is connected to both the coupling unit 10 and the FBG processing module 30; the control module 40 is connected to the FBG processing module 30.
Specifically, the coupling unit 10 is configured to receive a continuous optical signal and couple the continuous optical signal into a continuous optical test signal and a continuous optical working signal; the FBG processing module 30 is at least adapted to filter the received continuous optical test signal and to read the test optical power value P of the filtered continuous optical test signalMeasuring(ii) a The control module 40 is configured to: obtaining an initial optical power value P of a continuous optical test signal0And measuring the value of the optical power PMeasuring(ii) a Absolute value | P of difference between initial optical power value and test optical power valueMeasuring- P0And | compare with the preset optical power threshold Δ P, and when the absolute value of the difference is greater than the preset optical power threshold, control the FBG processing module 30 to adjust the temperature until the absolute value of the difference is less than or equal to the preset optical power threshold.
In the BOTDA system provided in the above embodiment, the coupling unit couples the continuous optical signal into two paths, i.e., a continuous optical test signal and a continuous optical working signal, at a preset splitting ratio, where the continuous optical test signal enters the FBG processing module through one path of the optical switch unit, and the FBG processing module performs filtering processing and detects a test optical power value of the filtered continuous optical test signal; the control module compares the absolute value of the difference value between the initial optical power value and the test optical power value with a preset optical power threshold value, controls the FBG processing module to adjust the temperature when the absolute value of the difference value is larger than the preset optical power threshold value until the absolute value of the difference value is smaller than or equal to the preset optical power threshold value, completes the automatic adjustment of the FBG central wavelength under the condition of not influencing the normal work of the BOTDA system, and improves the filtering effect of the continuous optical working signal passing through the external sensing optical fiber. Professional test equipment such as a spectrometer is not needed, the central wavelength of the FBG is automatically adjusted, the engineering debugging difficulty is reduced, the engineering practicability of the BOTDA system is improved, and the maintenance period of the BOTDA system is prolonged.
As an example, the coupling unit 10 outputs the continuous optical test signal and the continuous optical pulse signal at a preset splitting ratio, which is 1: 99. The preset threshold value delta P is 50 uW-200 uW, and the preset threshold value is influenced by light source fluctuation and the working state of an Electro-Optic Modulator (EOM).
As an example, the coupling unit 10 includes a coupler; the optical switch unit 20 includes 1 × 2 optical switches, and the 1 × 2 optical switches have two gate channels; the optical switch unit 20 includes a first optical input terminal, a second optical input terminal, and an optical output terminal. The first channel is from the first light input end to the light output end, and the second channel is from the second input end to the light output end; the control module 40 includes a single chip microcomputer or an industrial personal computer, etc.
As an example, the continuous optical test signal does not enter the external sensing optical fiber, so that the optical power change caused by SBS is avoided, and the continuous optical test signal is only subjected to EOM modulation and filtering action, so that the external interference is avoided. The continuous optical working signal enters the external sensing optical fiber and is subjected to the SBS action, and the optical power of the continuous optical working signal changes.
As an example, the unfiltered continuous optical test signal comprises anti-Stokes side bands, Stokes side bands and a central carrier wave, the filtered continuous optical test signal only has the anti-Stokes side bands, and the detected test optical power value PMeasuringIs the spectral power of the anti-stokes sidebands.
In one embodiment, as shown in fig. 2, the control module 40 is further configured to: the optical switch unit 20 is connected with a control end of the optical switch unit 20, and when the BOTDA system is debugged, the first optical input end of the optical switch unit 20 is controlled to be turned on and the second optical input end of the optical switch unit 20 is controlled to be turned off; or when the BOTDA system normally operates, the first optical input terminal of the optical switch unit 20 is controlled to be turned off and the second optical input terminal of the optical switch unit 20 is controlled to be turned on, so that the continuous optical working signal passing through the external sensing fiber is input to the FBG processing module 30.
Specifically, when the BOTDA system is debugged, the first optical input end of the optical switch unit 20 is controlled to be turned on and the second optical input end of the optical switch unit 20 is controlled to be turned off, that is, the first channel is gated by the optical switch unit 20; the turning off of the first optical input terminal of the optical switch unit 20 and the turning on of the second optical input terminal of the optical switch unit 20 are controlled, that is, the second channel is gated for the control of the optical switch unit 20, so that the continuous optical working signal subjected to the SBS action by the external sensing fiber is transmitted to the optical switch unit 20.
The BOTDA system provided by the above embodiment can freely switch two modes of the BOTDA system debugging and the BOTDA system normal operation through the optical switch unit 20, and set the regular or irregular automatic adjustment according to the actual needs of the use site, thereby realizing the function of regular maintenance.
In one embodiment, before the BOTDA system equipment leaves the factory, the temperature of the FBG is adjusted by matching the spectrometer with the FBG temperature control so as to determine the standard filtering window. The control module 40 controls the optical switch unit 20 to gate the first channel, and the continuous optical test signal corresponding to the standard filter window enters the FBG processing module 30 via the first channel in the optical switch unit 20, and the initial optical power value P corresponding to the standard filter window is obtained by detection0。
The initial optical power value P0The spectral power of the anti-stokes sideband before leaving the factory.
In one embodiment, as shown in fig. 3, the BOTDA system further includes: a first ring unit 50; the first ring unit 50 is configured to: the second end is connected to the coupling unit 10 via an external sensing fiber, and the third end is connected to the second optical input end of the optical switch unit 20.
In one embodiment, with continued reference to fig. 3, the BOTDA system further includes: BOTDA continuous light output and BOTDA pulsed light output. A BOTDA continuous light output configured to: is connected with the input end of the coupling unit 10 and is used for providing a continuous optical signal to the coupling unit 10; the BOTDA pulsed light output is configured to: connected to a first end of the first ring unit 50 for providing pulsed light signals to the first ring unit 50.
In one embodiment, with continued reference to fig. 3, the BOTDA system further comprises: a continuous light output flange and a pulsed light output flange. The continuous light output flange is configured to: the first end is connected with the coupling unit 10, and the second end is connected with an external sensing optical fiber; the pulsed light output flange is configured to: the first end is connected to the second end of the first ring unit 50, and the second end is connected to the external sensing fiber.
In one embodiment, with continued reference to fig. 3, the BOTDA system further includes: a second ring unit 60; the second ring unit 60 is configured to: the first end is connected to the optical output end of the optical switch unit 20, and the second end and the third end are connected to the FBG processing module 30.
As an example, the first and second ring units 50 and 60 each include a circulator.
In one embodiment, with continued reference to fig. 3, the FBG processing module 30 includes an FBG unit 31, an FBG temperature control unit 32 and a photo detection unit 33. The FBG unit 31 is configured to: the first end is connected with the second end of the second annular unit 60 and is used for filtering and processing the continuous optical test signal and the continuous optical working signal which passes through the external sensing optical fiber; the FBG temperature control unit 32 is configured to: the first end is connected with the second end of the FBG unit 31, the second end is connected with the control module 40, and the temperature of the FBG unit 31 is adjusted according to the control module 40; the photodetection unit 33 is configured to: the first end is connected to the third end of the second ring unit 60, and the second end is connected to the control module 40, and is configured to read a test optical power value of the filtered continuous optical test signal and a power value of the continuous optical working signal externally connected to the sensing fiber.
As an example, the Photo detection unit 33 includes a SIPM array detector, an Avalanche Photodiode (APD), or a Single Photon Avalanche photodiode (SPAD). The temperature control step length of the FBG temperature control unit 32 is set to 0.5-1 ℃, and can be adjusted according to actual requirements, which is not limited in the application.
By way of example, fig. 4 is a schematic spectral diagram of a continuous optical test signal; the FBG unit 31 includes an FBG which reflects the anti-stokes sideband which satisfies the central wavelength, and the spectrogram after the stokes sideband which does not satisfy the central wavelength and the central carrier are transmitted can refer to fig. 5, and only the anti-stokes sideband is maintained. The area enclosed by the test curve and the abscissa (wavelength) shown in fig. 4 and 5 is the optical power value of the signal, which can be detected and read by the photodetection unit 33.
As an example, the spectral linewidth of the FBG center wavelength is 0.1nm-0.2nm, and the spectral linewidth range is called FBG filter window; fig. 5 is a standard filter window of a continuous optical test signal obtained from a spectrometer test before shipment.
In one embodiment, when PMeasuringAnd P0When the difference of (d) is positive, the filter window is shifted to the right, as shown in fig. 6; the original suppressed central carrier power of the continuous optical test signal is increased, which results in the power detected by the photoelectric detection unit 33 being increased, and the control module 40 drives the FBG temperature control unit 32 to reduce the temperature of the FBG unit 31, thereby reducing the FBG central wavelength, and the FBG filter window is shifted to the left, so that the FBG filter window is located in the standard filter window.
In one embodiment, when PMeasuringAnd P0When the difference is negative, the filter window is shifted to the left, as shown in fig. 7; the anti-stokes sidebands of the continuous optical test signal are suppressed, resulting in a decrease in the optical power detected by the photodetection unit 33, and the control module 40 drives the FBG temperature control unit 32 to increase the temperature of the FBG unit 31, increasing the FBG center wavelength, so that the filter window is shifted to the right.
For ease of understanding the present application, the angles of optical path transmission of the continuous optical test signal and the continuous optical operating signal resulting from the coupling are illustrated in connection with fig. 3:
the BOTDA continuous optical output provides a continuous optical signal, and the coupling unit 10 divides the continuous optical signal into a continuous optical test signal and a continuous optical working signal at a preset splitting ratio; the BOTDA pulse light output provides a pulse light signal;
when the BOTDA system is debugged, the control module 40 opens the first optical input end of the optical switch unit 20, the continuous optical test signal enters the optical switch unit 20, then enters the FBG unit 31 via the second annular unit 60 for filtering, the filtered continuous optical test signal passes through the second annular unit 60 and is sent to the photoelectric detection unit 33, and the current test optical power value P is detectedMeasuring(ii) a The control module 40 compares | PSide survey- P0And a predetermined optical power threshold Δ P at |, PMeasuring- P0When | is greater than the preset optical power threshold Δ P, the FBG temperature control unit 32 is controlled to adjust the temperature of the FBG unit 31 until | PMeasuring- P0I is less than or equal to Δ P to modify the filter window of the FBG into the standard filter window.
When the BOTDA system normally works, the control module 40 turns on the second optical input end of the optical switch unit 20, the continuous optical working signal is sent to the second annular unit 60 and the photoelectric detection unit 33 via the continuous optical output flange, the external sensing optical fiber, the pulse optical output flange, the first annular unit 50, the second optical input end of the optical switch unit 20, the second annular unit 60, and the FBG unit 31 sends the filtered continuous optical working signal to the second annular unit 60.
In an embodiment of the present application, as shown in fig. 8, a BOTDA system control method is further provided, where the BOTDA system control method is applied to a BOTDA system, and the BOTDA system includes a coupling unit 10, an optical switch unit 20, an FBG processing module 30, and a control module 40; the control method comprises the following steps:
step S10: the control coupling unit 10 couples the continuous optical signal into a continuous optical test signal and a continuous optical working signal;
step S20: controlling the FBG processing module 30 to filter the continuous optical test signal and read the test optical power value of the filtered continuous optical test signal;
step S30: the control module 40 compares the absolute value of the difference between the initial optical power value and the tested optical power value with a preset optical power threshold, and controls the FBG processing module 30 to adjust the temperature when the absolute value of the difference is greater than the preset optical power threshold until the absolute value of the difference is less than or equal to the preset optical power threshold.
In one embodiment, the control method further comprises the steps of:
step S40: when the BOTDA system is debugged, the control module 40 controls the first optical input end of the optical switch unit 20 to be turned on and the second optical input end of the optical switch unit 20 to be turned off; or when the BOTDA system operates normally, the control module 40 controls the first optical input end of the optical switch unit 20 to be turned off and the second optical input end of the optical switch unit 20 to be turned on, so as to input the continuous optical working signal via the external sensing fiber to the FBG processing module 30.
In an embodiment of the present application, a storage medium is also proposed, on which a computer program is stored, which computer program, when being executed by a processor, realizes the steps of the method as described above.
For the specific limitations of the control method in the above embodiments, reference may be made to the limitations of the control method in the foregoing, and details are not described here.
It should be understood that the steps described are not to be performed in the exact order recited, and that the steps may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps described may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performing the sub-steps or stages is not necessarily sequential, but may be performed alternately or in alternation with other steps or at least some of the sub-steps or stages of other steps.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others.
It should be noted that the above-mentioned embodiments are only for illustrative purposes and are not meant to limit the present invention.
The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A BOTDA system, comprising:
the coupling unit is used for receiving the continuous optical signal and coupling the continuous optical signal into a continuous optical test signal and a continuous optical working signal;
an optical switch unit connected with the coupling unit;
the FBG processing module is connected with the optical switch unit and at least used for filtering the received continuous optical test signal and reading a test optical power value of the filtered continuous optical test signal;
a control module connected to the FBG processing module and the control end of the optical switch unit, and configured to:
acquiring an initial optical power value and the test optical power value of the continuous optical test signal;
comparing the absolute value of the difference value between the initial optical power value and the test optical power value with a preset optical power threshold, and controlling the FBG processing module to adjust the temperature when the absolute value of the difference value is greater than the preset optical power threshold until the absolute value of the difference value is less than or equal to the preset optical power threshold;
the control module is further configured to:
when the BOTDA system is debugged, controlling a first optical input end of the optical switch unit to be opened and a second optical input end of the optical switch unit to be closed; or
When the BOTDA system normally operates, the first optical input end of the optical switch unit is controlled to be switched off and the second optical input end of the optical switch unit is controlled to be switched on, so that continuous optical working signals through the external sensing optical fiber are input to the FBG processing module.
2. The BOTDA system of claim 1, wherein the control module comprises a single chip microcomputer or an industrial personal computer.
3. The BOTDA system of claim 1, further comprising:
a first ring unit configured to: the second end is connected with the coupling unit through an external sensing optical fiber, and the third end is connected with the second optical input end of the optical switch unit.
4. The BOTDA system of claim 3, further comprising:
a BOTDA continuous light output configured to: the input end of the coupling unit is connected with the optical signal processing unit and is used for providing the continuous optical signal to the coupling unit;
a BOTDA pulsed light output configured to: and the first end of the first annular unit is connected with the first end of the first annular unit and is used for providing pulsed light signals for the first annular unit.
5. The BOTDA system of claim 3, further comprising:
a continuous light output flange configured to: the first end is connected with the coupling unit, and the second end is connected with an external sensing optical fiber;
a pulsed light output flange configured to: the first end is connected with the second end of the first annular unit, and the second end is connected with an external sensing optical fiber.
6. The BOTDA system of claim 1, further comprising:
a second ring unit configured to: the first end with the photoswitch unit's optical output end is connected, the second end and the third end all with FBG handles the module connection.
7. The BOTDA system of claim 6, characterized in that the FBG processing module comprises:
an FBG unit configured to: the first end of the second annular unit is connected with the second end of the second annular unit and is used for filtering and processing the continuous optical test signal and the continuous optical working signal which is externally connected with a sensing optical fiber;
an FBG temperature control unit configured to: the first end is connected with the second end of the FBG unit, the second end is connected with the control module, and the temperature of the FBG unit is adjusted according to the control module;
a photodetecting unit configured to: the first end is connected with the third end of the second annular unit, the second end is connected with the control module, and the first end and the second end are used for reading the test optical power value of the filtered continuous optical test signal and the power value of the continuous optical working signal which is externally connected with the sensing optical fiber.
8. A BOTDA system control method is characterized in that the BOTDA system control method is applied to a BOTDA system, and the BOTDA system comprises a coupling unit, an optical switch unit, an FBG processing module and a control module; wherein the control method comprises the following steps:
controlling the coupling unit to couple the continuous optical signal into a continuous optical test signal and a continuous optical working signal;
controlling the FBG processing module to filter the continuous optical test signal and reading a test optical power value of the filtered continuous optical test signal;
controlling the control module to compare an absolute value of a difference value between an initial optical power value and the test optical power value with a preset optical power threshold value, and controlling the FBG processing module to adjust the temperature when the absolute value of the difference value is greater than the preset optical power threshold value until the absolute value of the difference value is less than or equal to the preset optical power threshold value;
the control method further comprises the following steps:
when the BOTDA system is debugged, the control module controls a first optical input end of the optical switch unit to be opened and a second optical input end of the optical switch unit to be closed; or
When the BOTDA system normally operates, the control module controls the first optical input end of the optical switch unit to be switched off and the second optical input end of the optical switch unit to be switched on, so that continuous optical working signals of external sensing optical fibers are input to the FBG processing module.
9. The BOTDA system control method according to claim 8, characterized in that the control module comprises a single chip microcomputer or an industrial personal computer.
10. A storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method according to any of claims 8 to 9.
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CN111189483A (en) * 2018-11-14 2020-05-22 中兴通讯股份有限公司 Distributed optical fiber sensing system, control method and control device thereof, and storage medium
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JP2013113830A (en) * 2011-12-01 2013-06-10 Hitachi Ltd Multipoint measuring method and multipoint measuring device, using fbg sensor
CN102589592A (en) * 2012-02-21 2012-07-18 南京大学（苏州）高新技术研究院 Multi-wavelength light source-based Brillouin optical time domain reflectometer
CN111189483A (en) * 2018-11-14 2020-05-22 中兴通讯股份有限公司 Distributed optical fiber sensing system, control method and control device thereof, and storage medium
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