Control device, signal processing method and light detection system

Abstract

Provided are a control device, a signal processing method and an optical detection system, which relate to the field of optical fiber sensing and can generate corresponding configuration information according to a detection signal and then generate a corresponding optical signal based on the generated configuration information, thereby improving the accuracy of detecting the optical fiber sensing system. The control device comprises a processing circuit and a control circuit. The processing circuit is used for generating first configuration information based on the first detection signal output by the receiving circuit and sending the first configuration information to the control circuit; the control circuit is used for generating a first modulation electric signal based on the first configuration information and sending the first modulation electric signal to the optical modulator, and the optical modulator is specifically used for modulating the first modulation electric signal to a carrier optical signal to generate a first modulation optical signal, the first configuration information comprises at least one of the following configuration values of the first modulation optical signal: the pulse number, the pulse width and the pulse shape. The embodiment of the invention is applied to the field of optical fiber sensing.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical fiber sensing, and in particular to a control device, a signal processing method and a light detection system. Background Art

[0002] Optical fiber sensing (OFS) technology has a broad market prospect and has been widely used in aerospace, industrial and mining enterprises, medicine and health and other fields. Optical fiber sensing technology can detect the backlight signal (opposite to the transmission direction, including scattered light signal and reflected light signal) generated when the optical signal is transmitted along the optical fiber, so as to detect the transmission distance and other parameters of the optical fiber sensing system. The transmission performance of the optical fiber sensing system can be reflected by phase noise (also called phase noise), signal to noise ratio (SNR) and dynamic range (DR). For example, the common optical time domain reflectometry (OTDR) system can measure the optical fiber loss, the phase-sensitive optical time domain reflectometry (φ-OTDR) system can measure the external stress and external sound waves, and the Brillouin optical pulse time domain reflectometry (BOTDR) system and the Raman optical pulse time domain reflectometry (ROTDR) system are often used to measure the external temperature.

[0003] Among them, the distributed optical fiber sensing technology can use the optical fiber as a sensing sensitive element and a medium for transmitting signals at the same time, and detect the changes in temperature and external stress at different positions of the optical fiber through OTDR to achieve distributed measurement of the optical fiber. The distributed optical fiber sensing system can be realized through frequency division multiplexing (FDM) technology, that is, within a time period, the transmitter sends an optical signal including different frequencies (also called pulses), and the filter deployed at the receiving end can measure the response corresponding to each frequency point included in the optical signal after transmission along the optical fiber, thereby finally obtaining the response of the distributed optical fiber sensing system.

[0004] However, the configuration of the optical signal usually sent by FDM technology is fixed, so it is difficult to apply to different optical fiber sensing systems. This may cause the scattered light signals generated by the optical signal transmitted along the optical fiber to be aliased in the time domain and cause crosstalk between signals. Summary of the invention

[0005] The present application provides a control device, a signal processing method and an optical detection system, which can generate corresponding configuration information according to a detection signal, and then generate a corresponding optical signal based on the generated configuration information, thereby improving the accuracy of detection of an optical fiber sensing system.

[0006] In the first aspect, a control device is provided. The control device is used in an optical detection system, the optical detection system includes a laser, an optical modulator and a receiving circuit; the optical modulator couples the laser and the optical fiber, and the receiving circuit couples the laser and the optical fiber; the receiving circuit is used to receive the carrier optical signal output by the laser and the first detection optical signal output by the optical fiber, and outputs a first detection signal in response to the carrier optical signal and the first detection optical signal; the control device includes: a processing circuit and a control circuit; the processing circuit is used to generate first configuration information based on the first detection signal output by the receiving circuit, and send the first configuration information to the control circuit; the control circuit is used to generate a first modulated electrical signal based on the first configuration information, and send the first modulated electrical signal to the optical modulator, and the optical modulator is specifically used to modulate the first modulated electrical signal to the carrier optical signal to generate the first modulated optical signal, wherein the first configuration information includes at least one of the following configuration values ​​of the first modulated optical signal: the number of pulses, the pulse width, and the pulse shape.

[0007] In this solution, the processing circuit of the control device can generate configuration information based on the detection signal and send it to the control circuit; the control circuit generates a modulated electrical signal based on the configuration information. When the control device is used in an optical detection system, the coherent detection of the optical fiber sensing system can be achieved by performing coherent detection on the carrier optical signal output by the laser and the modulated optical signal corresponding to the modulated electrical signal output by the optical fiber. Specifically, the control device can generate corresponding configuration information by performing coherent detection on the received carrier optical signal and the detection optical signal, and then generate corresponding optical signals through the laser and optical modulator included in the optical detection system. Then, the control device in this solution can generate corresponding configuration information based on the transmission performance of the optical fiber sensing system, thereby improving the accuracy of detection of the optical fiber sensing system.

[0008] In one possible implementation, the processing circuit is further used to generate initial configuration information; and send the initial configuration information to the control circuit; the control circuit is used to generate an initial modulated electrical signal based on the initial configuration information, and send the initial modulated electrical signal to the optical modulator, wherein the optical modulator is specifically used to modulate the initial modulated electrical signal into a carrier optical signal to generate an initial modulated optical signal, wherein the initial configuration information includes at least one of the following configuration values ​​of the initial modulated optical signal: the number of pulses, the pulse width, and the pulse shape; the optical fiber is used to generate a first detection optical signal based on the initial modulated optical signal, the receiving circuit receives the carrier optical signal output by the laser and the first detection optical signal output by the optical fiber, and outputs a first detection signal in response to the carrier optical signal and the first detection optical signal.

[0009] In this solution, the processing circuit included in the control device can generate initial configuration information and send it to the control circuit; the control circuit generates an initial modulated electrical signal according to the initial configuration information. The configuration value included in the initial configuration information can take any fixed value. When the control device is used in an optical detection system, a detection optical signal can be generated correspondingly based on the initial configuration information, and the receiving circuit can generate a detection signal in response to the carrier optical signal and the detection optical signal. Then, the control device in this solution can generate a certain initial configuration information whose configuration value takes an arbitrary fixed value, and generate a detection signal based on the correspondingly generated initial modulated optical signal, so that the optical signal generated corresponding to the configuration information can be used to detect the optical fiber sensing system.

[0010] In one possible implementation, the processing circuit specifically obtains characteristic parameters of the first detection signal, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameters of the first detection signal do not meet predetermined conditions, first configuration information is generated, wherein the pulse shape included in the first configuration information is different from the pulse shape included in the initial configuration information, and / or the pulse width included in the first configuration information is different from the pulse width included in the initial configuration information.

[0011] In this solution, the processing circuit included in the control device can judge whether the characteristic parameter meets the predetermined condition according to the characteristic parameter of the first detection signal obtained, and generate the first configuration information accordingly and send it to the control circuit. Since the characteristic parameter includes any one of the signal-to-noise ratio, phase noise and dynamic range, the processing circuit can generate the first configuration information accordingly according to whether the signal-to-noise ratio, phase noise and dynamic range meet the predetermined condition. In a possible implementation, when the phase noise of each frequency point of the first detection signal corresponding to a certain specific pulse shape exceeds the parameter threshold, the control device will adjust the pulse shape contained in the initial configuration information, and generate the first configuration information including the pulse shape different from the pulse shape contained in the initial configuration information. Of course, the above-mentioned characteristic parameter can also be the signal-to-noise ratio or the dynamic range, and the processing circuit can judge according to the characteristic parameter and the predetermined condition corresponding to the characteristic parameter, adjust the pulse shape included in the initial configuration information, and generate the first configuration information. In addition, the processing circuit can also adjust the pulse width contained in the initial configuration information to generate the first configuration information. Then, the control device in this scheme can make judgments based on characteristic parameters and predetermined conditions, adjust the pulse shape and / or pulse width contained in the initial configuration information, generate corresponding configuration information, and improve the accuracy of detection of the optical fiber sensing system.

[0012] In one possible implementation, the optical fiber is used to generate a second detection optical signal based on the first modulated optical signal; the receiving circuit is used to receive the carrier optical signal output by the laser and the second detection optical signal output by the optical fiber, and output the second detection signal in response to the carrier optical signal and the second detection optical signal; the processing circuit is also used to obtain characteristic parameters of the second detection signal based on the second detection signal output by the receiving circuit, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the second detection signal do not meet predetermined conditions, second configuration information is generated, wherein the pulse shape contained in the second configuration information is different from the pulse shape contained in the first configuration information, and / or the pulse width contained in the second configuration information is different from the pulse width contained in the first configuration information.

[0013] In this solution, the control device can obtain the characteristic parameters of the second detection signal based on the first modulated optical signal, and can generate the second configuration information and send it to the control circuit according to whether the characteristic parameters meet the predetermined conditions. In a possible implementation, the control device in the above solution has adjusted the initial configuration information according to the characteristic parameters corresponding to the first detection signal and the predetermined conditions, and correspondingly generated the first configuration information. Further, the control device in this solution can adjust the pulse shape and / or pulse width included in the first configuration information by judging that the characteristic parameters of the second detection signal based on the first configuration information do not meet the predetermined conditions, and generate the second configuration information. In a possible implementation, when the phase noise of each frequency point of the first detection signal corresponding to a certain specific pulse shape exceeds the parameter threshold, the control device will generate the first configuration information containing a pulse shape different from the pulse shape contained in the initial configuration information. If the phase noise of each frequency point of the second detection signal still exceeds the parameter threshold, the control device will generate the second configuration information containing a pulse shape different from the pulse shape contained in the first configuration information. Furthermore, the optical modulation can generate a new modulated optical signal according to the second configuration information. Of course, if the detection signal based on the new modulated optical signal still cannot meet the predetermined conditions, the control device can further continue to generate new configuration information, and repeat this cycle until the generated detection signal meets the predetermined conditions. Of course, the above-mentioned predetermined conditions are only an example, and the above-mentioned characteristic parameters can also be signal-to-noise ratio or dynamic range. In addition, the processing circuit can also adjust the pulse width contained in the configuration information to generate corresponding configuration information. In this way, the pulse shape (or pulse width) included in the optical signal generated corresponding to the generated configuration information is different, and the optical signal can realize the detection of more types of optical fiber sensing systems. Then, the control device in this scheme realizes higher-precision detection of different optical fiber sensing systems by continuously adjusting the configuration information and generating corresponding configuration information based on multiple judgments on the characteristic parameters and predetermined conditions.

[0014] In one possible implementation, the optical fiber is used to generate a second detection optical signal based on the first modulated optical signal; the receiving circuit is used to receive the carrier optical signal output by the laser and the second detection optical signal output by the optical fiber, and output the second detection signal in response to the carrier optical signal and the second detection optical signal; the processing circuit is also used to obtain characteristic parameters of the second detection signal based on the second detection signal output by the receiving circuit, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameters of the second detection signal meet predetermined conditions, the first configuration information is sent to the control circuit.

[0015] In this solution, the control device determines that the characteristic parameter of the second detection signal based on the first modulated optical signal meets the predetermined condition, and can send the first configuration information to the control circuit. In a possible implementation, the control device in the above solution has generated the first configuration information by adjusting the initial configuration information. Further, the control device in this solution can send the first configuration information to the control circuit by determining that the characteristic parameter of the second detection signal meets the predetermined condition. In a possible implementation, when the phase noise of each frequency point of the first detection signal corresponding to a certain pulse shape exceeds the parameter threshold, the control device will generate the first configuration information containing a pulse shape different from the pulse shape contained in the initial configuration information; further, when the phase noise of each frequency point of the second detection signal corresponding to a certain pulse shape does not exceed the parameter threshold, the control device will generate a first modulated optical signal corresponding to the first configuration information. Of course, the above predetermined condition is only an example, and the above characteristic parameter can also be a signal-to-noise ratio or a dynamic range. Then, the control device in this solution can finally determine a certain configuration information (such as the first configuration information) in the generated configuration information, and the configuration information can achieve higher precision detection of the optical fiber sensing system.

[0016] In one possible implementation, the processing circuit specifically obtains characteristic parameters of the first detection signal, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameters of the first detection signal meet predetermined conditions, first configuration information is generated, wherein the number of pulses included in the first configuration information is greater than the number of pulses included in the initial configuration information.

[0017] In this solution, the processing circuit included in the control device can determine whether the characteristic parameter of the first detection signal obtained meets the predetermined condition, and generate the first configuration information accordingly and send it to the control circuit. If the characteristic parameter of the first detection signal based on the initial configuration information meets the predetermined condition, the processing circuit can adjust the number of pulses included in the initial configuration information, and generate the first configuration information accordingly. For example, when the phase noise of each frequency point of the first detection signal corresponding to a certain number of pulses does not exceed the parameter threshold, the processing circuit will adjust the number of pulses included in the initial configuration information, and generate the first configuration information containing a number of pulses greater than the number of pulses contained in the initial configuration information. Of course, the above-mentioned characteristic parameters can also be signal-to-noise ratio or dynamic range. Then, the control device in this solution can make a judgment based on the characteristic parameters and the predetermined condition, and generate the corresponding configuration information by adjusting the number of pulses contained in the initial configuration information, thereby improving the accuracy of detection of optical fiber sensing systems with different system bandwidths.

[0018] In one possible implementation, the processing circuit is also used to obtain characteristic parameters of the second detection signal based on the second detection signal output by the receiving circuit, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameters of the second detection signal meet predetermined conditions, second configuration information is generated, wherein the number of pulses included in the second configuration information is greater than the number of pulses included in the first configuration information; and the second configuration information is sent to the control circuit.

[0019] In this solution, the control device determines that the characteristic parameter of the second detection signal based on the first modulated optical signal meets the predetermined condition, and can generate the second configuration information accordingly and send it to the control circuit. In a possible implementation, the control device in the above solution has adjusted the number of pulses of the initial configuration information, and the first configuration information is generated accordingly. If the characteristic parameter of the second detection signal based on the first configuration information still meets the predetermined condition, the processing circuit can adjust the number of pulses included in the first configuration information, and generate the second configuration information accordingly. For example, when the phase noise of each frequency point of the first detection signal corresponding to a certain number of pulses does not exceed the parameter threshold, the control device will generate the second configuration information containing a number of pulses greater than the number of pulses contained in the first configuration information, and the control device will generate a second modulated optical signal corresponding to the second configuration information. Of course, the above predetermined condition is only an example, and the above characteristic parameter can also be a signal-to-noise ratio or a dynamic range. In this way, the optical signal generated corresponding to the generated configuration information may include more pulses, and the optical signal can improve the accuracy of detecting more types of optical fiber sensing systems (such as optical fiber sensing systems with a wider system bandwidth). Then, the control device in this solution generates corresponding configuration information by continuously adjusting the number of pulses included in the configuration information based on multiple judgments on the characteristic parameters and predetermined conditions, thereby being able to achieve higher-precision detection of more different optical fiber sensing systems.

[0020] In a second aspect, a signal processing method is provided. The signal processing method is used in an optical detection system, wherein the optical detection system includes a laser, an optical modulator, and a receiving circuit; the optical modulator couples the laser and the optical fiber, and the receiving circuit couples the laser and the optical fiber; the receiving circuit is used to receive a carrier optical signal output by the laser and a detection optical signal output by the optical fiber, and output a detection signal in response to the carrier optical signal and the detection optical signal;

[0021] The signal processing method includes: generating first configuration information based on a first detection signal; generating a first modulated electrical signal based on the first configuration information, and sending the first modulated electrical signal to an optical modulator, wherein the optical modulator is specifically used to modulate the first modulated electrical signal onto a carrier optical signal to generate a first modulated optical signal, wherein the first configuration information includes at least one of the following configuration values ​​of the first modulated optical signal: number of pulses, pulse width, and pulse shape.

[0022] In a possible implementation, first configuration information is generated based on a first detection signal, and the process also includes: generating initial configuration information; generating an initial modulated electrical signal based on the initial configuration information, and sending the initial modulated electrical signal to an optical modulator, wherein the optical modulator is specifically used to modulate the initial modulated electrical signal into a carrier optical signal to generate an initial modulated optical signal, wherein the initial configuration information includes at least one of the following configuration values ​​of the modulated optical signal: number of pulses, pulse width, and pulse shape.

[0023] In one possible implementation, characteristic parameters of a first detection signal are obtained, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameters of the first detection signal do not meet predetermined conditions, first configuration information is generated, wherein a pulse shape included in the first configuration information is different from a pulse shape included in the initial configuration information, and / or a pulse width included in the first configuration information is different from a pulse width included in the initial configuration information.

[0024] In a possible implementation, based on the second detection signal output by the receiving circuit, a characteristic parameter of the second detection signal is obtained, and the characteristic parameter includes any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameter of the second detection signal does not meet the predetermined condition, the second configuration information is generated, wherein the pulse shape included in the second configuration information is different from the pulse shape included in the first configuration information, and / or the pulse width included in the second configuration information is different from the pulse width included in the first configuration information. If the characteristic parameter of the first detection signal meets the predetermined condition, the first configuration information is still generated.

[0025] In one possible implementation, characteristic parameters of a first detection signal are obtained, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameters of the first detection signal meet predetermined conditions, first configuration information is generated, wherein the number of pulses included in the first configuration information is greater than the number of pulses included in the initial configuration information.

[0026] In one possible implementation, based on the second detection signal output by the receiving circuit, characteristic parameters of the second detection signal are obtained, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range; if the characteristic parameters of the second detection signal meet predetermined conditions, second configuration information is generated, wherein the number of pulses included in the second configuration information is greater than the number of pulses included in the first configuration information.

[0027] In a third aspect, a light detection system is provided. The light detection system comprises: a laser, an optical modulator, and a receiving circuit; the optical modulator is coupled to the laser and the optical fiber, and the receiving circuit is coupled to the laser and the optical fiber; the receiving circuit is used to receive the carrier optical signal output by the laser and the detection optical signal output by the optical fiber, and outputs a detection signal in response to the carrier optical signal and the detection optical signal; and the control device as described in any one of the first aspects.

[0028] Among them, the technical effects brought about by any design method in the second aspect and the third aspect can refer to the technical effects brought about by different design methods in the above-mentioned first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A schematic diagram of an application scenario provided for an embodiment of the present application;

[0030] Figure 2 A schematic diagram of an optical fiber sensing system provided in an embodiment of the present application;

[0031] Figure 3 A schematic diagram of an optical fiber sensing system provided in accordance with another embodiment of the present application;

[0032] Figure 4 A schematic diagram of an optical fiber sensing system provided in accordance with another embodiment of the present application;

[0033] Figure 5 A schematic diagram of an FDM solution provided for an embodiment of the present application;

[0034] Figure 6 A schematic diagram of a control device provided in an embodiment of the present application;

[0035] Figure 7 A schematic diagram of a signal processing method provided in an embodiment of the present application;

[0036] Figure 8 A schematic diagram of a signal processing method provided for another embodiment of the present application;

[0037] Fig. 9 A schematic diagram of configuration information provided for an embodiment of the present application;

[0038] Fig.10 A schematic diagram of configuration information provided for another embodiment of the present application;

[0039] Fig.11 A schematic diagram of an OTDR system provided in an embodiment of the present application;

[0040] Fig.12 A schematic diagram of configuration information provided for yet another embodiment of the present application. DETAILED DESCRIPTION

[0041] The technical solution in the present application will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0042] The present application will present various aspects, embodiments or features around a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all devices, components, modules, etc. discussed in conjunction with the accompanying drawings. In addition, a combination of these schemes may also be used. It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific manner.

[0043] Optical fiber sensing technology OFS has been widely used in aerospace, industrial and mining enterprises, medicine and health, and other fields. Optical fiber sensing systems (optical fiber transmission systems using optical fiber sensing technology) can detect the backlight signals (including scattered light signals generated by Rayleigh scattering of optical signals and reflected light signals generated by Fresnel reflection of optical signals and Fresnel reflection of optical signals) generated by the Fresnel reflection and Rayleigh scattering when the optical signals are transmitted along the optical fiber, so as to detect the transmission distance and other parameters of the optical fiber sensing system. Among them, the transmission performance of the optical fiber sensing system can be reflected by phase noise or phase noise, signal-to-noise ratio SNR and dynamic range DR. In addition, in order to ensure the transmission performance of the optical fiber sensing system, other parameters that affect the transmission performance of the optical fiber sensing system can also be detected, such as external stress, external sound waves, external temperature, etc.

[0044] For example, refer to Figure 1 As shown, possible application scenarios of fiber optic sensing technology are shown. Figure 1 (1) shows the scene of buried pipelines. Figure 1 (2) shows the perimeter security protection scenario. Figure 1 (3) shows the scenario of deploying submarine optical cables. Since the vibration signal caused by the intrusion behavior will affect the optical fiber, by detecting the optical signal (such as the scattered light signal) output by the optical fiber, the intrusion event that poses a security threat can be discovered in time. In this way, when an intrusion occurs, by detecting the optical signal output by the received optical fiber, the vibration signal generated by the intrusion behavior in the optical fiber sensing system can be detected. Figure 1(4) shows a scenario of underground survey. Since optical fibers can be deployed underground, the optical fiber sensing system usually deploys a longer length of optical fiber underground. By detecting the optical signal (such as the reflected light signal) output by the optical fiber, the temperature of the optical fiber at different depths can be determined, thereby obtaining the composition and structural information at different depths underground, and providing guidance information for underground mining. In this way, by detecting the optical signal output by the optical fiber, the temperature of optical fibers of different lengths can be detected. Of course, only several scenarios in which optical fiber sensing technology may be applied are described here. In some other examples, optical fiber sensing technology also has other application scenarios, such as: distributed optical fiber acoustic wave sensing system, distributed temperature / stress sensing system, etc.

[0045] For example, refer to Figure 2 As shown, a possible optical fiber sensing system is shown. The optical fiber sensing system includes a transmitting end, a receiving end, and an optical fiber; wherein the transmitting end can send an optical signal to the optical fiber, and the optical signal is transmitted along the optical fiber to the receiving end, and the receiving end receives the optical signal. Specifically, by detecting the optical signal received by the receiving end, the transmission distance of the optical fiber, the external stress, external sound wave, external temperature, etc. of the optical fiber sensing system can be obtained. Further, referring to Figure 3 As shown, if the receiving end obtains the transmission distance of the optical fiber, the external stress, external sound wave, external temperature and other parameters of the optical fiber sensing system are fed back to the sending end, the sending end can set the optical signal to be sent later.

[0046] However, when there is a failure in the optical fiber transmission, such as a breakpoint, the receiving end will not be able to receive the optical signal, nor can it detect the received optical signal. Then, the above scheme will not be able to detect the transmission distance of the optical fiber, the external stress, external sound waves, external temperature, etc. of the optical fiber sensing system. In addition, in the actual optical fiber sensing system, the distance between the receiving end and the transmitting end is usually very far, and it takes a long time for the receiving end to complete the detection and then feed back the relevant parameters to the transmitting end, which may cause system delays, causing the transmitting end to continue to send the previous optical signal.

[0047] Based on the above problems, for example, refer to Figure 4 As shown, a possible optical fiber sensing system is shown. The optical fiber sensing system includes a transmitting end, a receiving end, an optical fiber, and an optical time domain reflectometer; wherein the OTDR is connected to the optical fiber and is connected to the proximal end of the transmitting end of the optical fiber sensing system. The OTDR is an instrument that can be applied to optical fibers and is used for feature analysis, troubleshooting, and maintenance of optical fiber sensing systems; it can locate optical fiber fault points, and can also detect the location and overall condition of optical fiber joint loss, connection, defects, and other parameters of the optical fiber sensing system of interest.

[0048] Specifically, OTDR generates and outputs optical signals to optical fibers. Fresnel reflection, Rayleigh scattering, and other phenomena may occur in the optical fibers, and a portion of the backlight signals transmitted to the transmitting end will be generated. OTDR processes the received backlight signals and can obtain data reflecting the conditions of the detected indicators inside the optical fiber, thereby realizing the detection of the corresponding parameters of the optical fiber sensing system. For example, the OTDR system (optical fiber sensing system using OTDR) can measure optical fiber loss, the φ-OTDR system (optical fiber sensing system using φ-OTDR) can measure external stress and external sound waves, and the BOTDR system (optical fiber sensing system using BOTDR) and the ROTDR system (optical fiber sensing system using ROTDR) are often used to measure external temperature.

[0049] Generally, fields such as oil and gas, electricity, and mines all require the deployment of long-distance distributed sensors to detect fiber optic sensing systems. As optical fiber has the advantages of being lightweight and passive, it has gradually become an ideal distributed sensor. Specifically, distributed fiber optic sensing technology can use optical fiber as both a sensing sensitive element and a medium for transmitting signals. Through OTDR, it can detect changes in temperature and external stress at different locations of the optical fiber, thereby achieving distributed detection of the optical fiber. Distributed fiber optic sensing systems can usually be implemented through FDM technology, that is, the transmitter sends an optical signal including multiple different pulse signals within a time period. By deploying a filter at the receiving end, the responses corresponding to each pulse signal included in the optical signal after it is transmitted along the optical fiber can be measured, thereby ultimately obtaining the response of the distributed fiber optic sensing system.

[0050] A common fiber optic sensing system that can achieve distributed detection is the φOTDR system. Specifically, the φOTDR system outputs an optical signal including multiple pulses through the OTDR to transmit in the optical fiber, and the optical signal will generate different scattered light when it is transmitted along the optical fiber. Since different scattered light signals arrive at the receiving unit at different times, distributed detection of the φOTDR system can be achieved. However, in order to ensure that the optical signals output by the OTDR at adjacent moments do not alias, the corresponding scattered light signals need not alias in the frequency domain. Therefore, the interval between two adjacent moments of the OTDR output optical signal needs to be greater than the sum of the time the optical signal is transmitted along the optical fiber and the time the scattered light signal arrives at the receiving unit. For example, when the length of the optical fiber to be detected is 25km, the interval between adjacent moments of the OTDR output optical signal should be at least greater than 250μs. That is, the period of the optical signal is 4kHz, and the corresponding system bandwidth is 2kHz.

[0051] Generally, the system bandwidth that a fiber optic sensing system can detect is mutually constrained by the length of the fiber in the fiber optic sensing system. For example, when the fiber length is 50 km, it takes about 500 μs for the scattered light signal to reach the receiving unit through the fiber. In order to ensure that the optical signals at adjacent moments do not overlap, it is necessary to ensure that the period of the optical signal is approximately 2 kHz. According to the Nyquist sampling theorem, the fiber optic sensing system can only detect through optical signals with a period of less than 1 kHz.

[0052] Well, although the above scheme can detect different fiber optic sensing systems by using the optical signal generated by the OTDR deployed at the transmitting end. However, since the number of frequency points included in the generated optical signal is fixed, the configuration of the generated optical signal cannot be changed in combination with the different fiber optic sensing systems being detected, which will result in low detection accuracy. In addition, in the fiber optic sensing system using FDM technology, the above scheme may also cause aliasing of scattered light signals generated by the transmission of optical signals along the optical fiber, and crosstalk between signals. For example, in the φOTDR system using FDM, scattered light signals generated by the transmission of optical signals of different frequencies along the optical fiber may be aliased in the time domain.

[0053] Based on the above problems, a theoretical solution for FDM corresponding to the optical fiber sensing system is usually given directly. Figure 5 As shown, a schematic diagram of an FDM scheme for a fiber optic sensing system is provided. The FDM scheme mainly adjusts the number of pulses included in the configuration information of the optical signal sent by the transmitter to N, that is, the optical signal sent by the transmitter in one cycle includes N frequency points, so that the frequency sweep signal is adjusted to N frequency bands in one cycle. In this way, the optical signal can adapt to the transmission performance of the fiber optic sensing system to ensure the accuracy of the measurement of the communication system. Combined with Figure 5 (1), where the horizontal axis is time, in seconds (s), and the vertical axis is frequency, in Hertz (Hz). Specifically, the corresponding optical signal in the FDM scheme is in one cycle ( Figure 5 The optical signal includes N frequency points, that is, the number of pulses included in the optical signal is N. Figure 5 (2), where the horizontal axis is time, in seconds (s), and the vertical axis is optical power, in decibel milliwatts (dBm). Specifically, the corresponding optical signal in the FDM scheme is in one cycle ( Figure 5 The optical powers of the N pulses included in (indicated as τ) are the same. Figure 5 (3), where the horizontal axis is time, in seconds (s), and the vertical axis is frequency, in Hz. Specifically, the corresponding optical signal in the FDM scheme is in one cycle ( Figure 5The pulse signal (marked as T) includes three different pulses with a frequency range of F1, a frequency range of F2 and a frequency range of F3.

[0054] Although the above scheme is feasible in theory, it is difficult to conduct specific analysis in combination with different fiber optic sensing systems. The proposed FDM scheme can only theoretically realize the transmission of an optical signal including N different pulses in one cycle, and modify the frequency sweep of a single fixed frequency pulse in one cycle to the frequency sweep of N frequency band pulses in one cycle. Since the specific selection process of the configuration of the optical signal is not given, it is difficult for the fiber optic sensing system to implement specific settings for the configuration of the optical signal. Therefore, it is difficult for this scheme to ensure that the configuration of the generated optical signal can achieve accurate detection of different fiber optic sensing systems.

[0055] Based on the above problems, when detecting different optical fiber sensing systems, it is necessary to timely adjust and generate corresponding configuration information according to the transmission performance of the optical fiber sensing system. Furthermore, the optical signal generated based on the generated configuration information can improve the accuracy of the detection of the optical fiber sensing system. Figure 6 As shown, an embodiment of the present application provides a schematic diagram of a control device, which is applied to a light detection system. Figure 6 As shown, the control device 40 includes: a processing circuit 401 and a control circuit 402; the processing circuit 401 is used to generate configuration information based on the detection signal output by the receiving circuit 403, and send the configuration information to the control circuit 402; the control circuit 402 is used to generate a modulated electrical signal based on the configuration information, and send the modulated electrical signal to the optical modulator 404. The configuration information includes at least one of the following configuration values ​​of the modulated optical signal corresponding to the modulated electrical signal: the number of pulses, the pulse width, and the pulse shape.

[0056] Exemplary, combined Figure 6 As shown, a light detection system applicable to a control device is provided. Generally, the light detection system includes a receiving circuit ( Figure 6 403 in), optical modulator ( Figure 6 404) and lasers ( Figure 6405 in the figure); the optical modulator 404 couples the laser 405 and the optical fiber, and the receiving circuit 403 couples the laser 405 and the optical fiber. The receiving circuit 403 is used to receive the carrier optical signal output by the laser 405 and the detection optical signal output by the optical fiber, and outputs the detection signal in response to the carrier optical signal and the detection optical signal. It is not difficult to understand that when the optical signal is transmitted along the optical fiber in the transmission direction, Fresnel reflection, Rayleigh scattering, etc. will occur, and a backlight signal (including scattered light signal and reflected light signal) opposite to the transmission direction will be generated. The backlight signal will be transmitted along the optical fiber to the transmitting end and received by the receiving circuit 403. The receiving circuit 403 responds to the backlight signal and outputs a detection signal. Of course, this is only used as an example to illustrate the process of the receiving circuit 403 outputting the detection signal. In a possible implementation, the receiving circuit 403 can also output a detection signal based on other received optical signals (such as a carrier optical signal).

[0057] Specific, combined Figure 6 As shown, the processing circuit 401 receives the detection signal output by the receiving circuit 403, generates configuration information based on the detection signal, and sends the configuration information to the control circuit 402. The control circuit 402 receives the configuration information output by the processing circuit 401, generates a modulated electrical signal based on the configuration information, and sends the modulated electrical signal to the optical modulator 404. The optical modulator 404 receives the modulated electrical signal, modulates the modulated electrical signal to the carrier optical signal to generate a modulated optical signal, and outputs it to the optical fiber. The modulated optical signal is transmitted along the optical fiber in the transmission direction.

[0058] Optionally, at the initial moment, the control device 40 can generate initial configuration information through the processing circuit 401, and send the initial configuration information to the control circuit 402; the control circuit 402 can generate an initial modulated electrical signal according to the received initial configuration information, and send the initial modulated electrical signal to the optical modulator 404. The optical modulator 404 can modulate the initial modulated electrical signal to the carrier optical signal to generate an initial modulated optical signal, wherein the initial configuration information includes at least one of the following configuration values ​​of the initial modulated optical signal: the number of pulses, the pulse width, and the pulse shape. Then, the control device can generate a certain initial configuration information whose configuration value is an arbitrary fixed value, and generate a detection signal based on the corresponding generated initial modulated optical signal, so that the optical signal generated corresponding to the configuration information can be used to detect the optical fiber sensing system.

[0059] Optionally, the control device 40 may further include a coupler 406, which is connected to the receiving circuit 403, the optical modulator 404 and the laser 405; and is used to transmit the carrier optical signal output by the laser 405 to the receiving circuit 403, so that the receiving circuit 403 can realize coherent detection of the optical fiber sensing system based on the carrier optical signal and the detection optical signal output by the optical fiber.

[0060] In a possible implementation, the control device 40 may further include a circulator 407, which is connected to the receiving circuit 403, the optical fiber, and the optical modulator 404; and is used to transmit the modulated optical signal output by the optical modulator 404 to the optical fiber, and is also used to transmit the detection optical signal output by the optical fiber to the receiving circuit 403.

[0061] It is not difficult to understand that the processing circuit 401 can be a general-purpose central processing unit (CPU), a microprocessor, or an application specific integrated circuit (ASIC). In a possible implementation, the functions implemented by the processing circuit 401 can be implemented by a processor.

[0062] For the sake of explanation, only Figure 6 The illustrated architecture is taken as an example, and should not be used to limit the specific structure of the control device and the light detection system used in the control device.

[0063] Combination Figure 6 As shown, in a possible implementation, the processing circuit 401 also includes a calculation unit, a control unit, and an adjustment unit. Specifically, the calculation unit is used to perform calculations based on the detection signal output by the receiving circuit, and output the calculation results to the control unit and the adjustment unit; the control unit is used to receive the calculation results of the calculation unit, determine whether the calculation results meet certain conditions, and output the determination results to the adjustment unit; the adjustment unit is used to receive the determination results and the calculation results, adjust the calculation results according to the received determination results, and generate configuration information.

[0064] Optionally, the control circuit 402 includes a generating unit, a shaping unit, and a synthesizing unit. Specifically, the generating unit is used to generate one or more corresponding electrical signals for generating pulses based on the number of pulses in the configuration information, and output them to the shaping unit; the shaping unit is used to shape the electrical signal of the pulse according to the pulse shape and pulse width in the configuration information, and send the shaped electrical signal of one or more pulses to the synthesizing unit; the synthesizing unit is used to synthesize the received electrical signal of one or more pulses into a modulated electrical signal, and output it to the optical modulator. Of course, the control circuit 402 may also include multiple groups of generating units and shaping units. The control circuit 402 may control the corresponding number of generating units to generate corresponding electrical signals of pulses according to the number of pulses, and the corresponding number of shaping units to shape the electrical signals of each pulse respectively.

[0065] In this way, the above-mentioned control device can be deployed in the optical fiber sensing system as an independent device, wherein the control device can be connected to the interface circuit of the optical detection system through the processing circuit, and the control device can be connected to the optical modulator of the optical detection system through the control circuit. At different times, the control device included in the above-mentioned scheme can also adjust the configuration value included in the configuration information of the received detection signal, generate new configuration information, and generate a modulated electrical signal according to the new configuration information. Furthermore, the modulated electrical signal is modulated to the carrier optical signal by the optical modulator to generate a corresponding modulated optical signal. Then, by applying the control device to the optical detection system, an optical signal corresponding to the transmission performance of the optical fiber sensing system can be generated, so that the optical detection system can detect the optical fiber sensing system with higher accuracy, and can also reduce costs and improve the transmission efficiency of the optical fiber sensing system.

[0066] based on Figure 6 The control device shown, for example, is shown in FIG. Figure 7 As shown, the embodiment of the present application provides a signal processing method. Figure 7 , the signal processing method provided in the embodiment of the present application is described in detail. Figure 6 The signal processing method includes steps 601 to 603, which are described in detail as follows.

[0067] Step 601: Generate configuration information based on the detection signal.

[0068] Combination Figure 7 As shown, the control device includes a processing circuit, which generates configuration information based on the detection signal. Specifically, the control device includes a processing circuit, which is used to generate configuration information based on the detection signal and output it to the control circuit.

[0069] For example, the initial detection signal is f0 = -f s / 2+1 / τ, where fs is the system bandwidth, the pulse width is τ, and the number of pulses N is 2. Then, the initial configuration information can be generated by the processing circuit: the pulse width is τ, the number of pulses N is 2; the pulse shape is a rectangle m=1.

[0070] Step 602: Generate a modulated electrical signal based on the configuration information.

[0071] Combination Figure 7 As shown, the control device includes a control circuit, which generates a modulated electrical signal based on the configuration information. Specifically, the control device includes a control circuit, which is used to generate a modulated electrical signal based on the received configuration information.

[0072] In combination with step 601, optionally, the control device at the initial moment can generate an initial modulated electrical signal based on the received initial configuration information through the control circuit. Optionally, at the first moment (a moment after the initial moment), the control device can generate a first modulated electrical signal based on the received first configuration information through the control circuit. In addition, in other examples, at the second moment (a moment after the first moment), the control device can also generate a second modulated electrical signal based on the received second configuration information through the control circuit.

[0073] Step 603: Send the modulated electrical signal to the optical modulator.

[0074] Combination Figure 7 As shown, the control device includes a control circuit that sends the modulated electrical signal to the optical modulator. Specifically, the control device includes a control circuit that is used to send the modulated electrical signal to the optical modulator. Generally, the optical modulator can modulate the modulated electrical signal to a carrier optical signal to generate a modulated optical signal, wherein the configuration information includes at least one of the following configuration values ​​of the modulated optical signal: the number of pulses, the pulse width, and the pulse shape.

[0075] Then, the processing circuit of the above-mentioned control device can generate configuration information according to the detection signal and send it to the control circuit; the control circuit generates a modulated electrical signal according to the configuration information. In this way, when the control device is used for optical detection equipment, it can realize coherent detection of the optical fiber sensing system through the carrier optical signal output by the laser and the modulated optical signal corresponding to the modulated electrical signal output by the optical fiber, so that the detection accuracy of the optical fiber sensing system is higher. Specifically, the control device can generate configuration information for generating the modulated electrical signal based on the detection signal, and the corresponding optical signal can be generated by the laser and the optical modulator included in the optical detection system. Then, through this scheme, the control device can ensure that the transmitting end of the optical fiber sensing system can adaptively generate the configuration value of the optical signal, such as the number of pulses, pulse width and pulse shape, according to the transmission performance of the optical fiber sensing system, so that the transmission performance of the optical fiber sensing system is better and the detection accuracy of the optical fiber sensing system is higher.

[0076] Based on the above signal processing method, exemplary, refer to Figure 8 As shown, the embodiment of the present application also provides a signal processing method. Figure 8 , the signal processing method provided in the embodiment of the present application is described in detail. Figure 6 The signal processing method includes steps 701 to 704, which are described in detail as follows.

[0077] Step 701: Acquire a detection signal.

[0078] Combination Figure 8As shown, the control device includes a processing circuit for acquiring a detection signal. Specifically, the control device includes a processing circuit for acquiring a detection signal.

[0079] Optionally, the receiving circuit can output a detection signal in response to the carrier optical signal and the detection optical signal by receiving the carrier optical signal output by the laser and the detection optical signal output by the optical fiber.

[0080] Step 702: Acquire characteristic parameters of the detection signal.

[0081] Combination Figure 8 As shown, the control device includes a processing circuit for obtaining characteristic parameters of the detection signal. Specifically, the control device includes a processing circuit for obtaining characteristic parameters of the detection signal, and the characteristic parameters include any of the following: signal-to-noise ratio, phase noise, and dynamic range.

[0082] Step 703: Adjust the configuration values ​​included in the configuration information to generate the configuration information.

[0083] Combination Figure 8 As shown, the control device includes a processing circuit, when the characteristic parameter does not meet the predetermined condition, adjusts the configuration value included in the configuration information to generate the configuration information. Specifically, the control device includes a processing circuit, which is used to determine that the characteristic parameter does not meet the predetermined condition, adjust the configuration value included in the configuration information, and generate the configuration information; the control device also includes a control circuit, which is used to generate a modulated electrical signal based on the generated configuration information, and output it to the optical modulator. The optical modulator can modulate the modulated electrical signal to the carrier optical signal to generate a modulated optical signal.

[0084] It is not difficult to understand that the predetermined condition can be that the configuration value included in the configuration information does not exceed a fixed preset threshold, or that the characteristic parameter of the detection signal can increase the dynamic range of the corresponding optical fiber sensing system by a fixed value. Those skilled in the art can flexibly set it according to actual needs.

[0085] For example, the first moment control device obtains the characteristic parameters of the initial detection signal through the processing circuit. If the phase noise of the initial detection signal exceeds -40dB / Hz, the pulse shape included in the initial configuration information (for example, the initial configuration information includes: the pulse width is τ, the number of pulses N is 2; the pulse shape is a rectangle m=1) is adjusted to generate the first configuration information. The pulse shape included in the first configuration is different from the pulse shape included in the initial configuration information. Then, combined with Figure 7 In steps 601-603, the control device can generate a corresponding first modulated electrical signal based on the first configuration information. The first modulated optical signal is generated by an optical modulator.

[0086] It is not difficult to understand that the configuration value included in the adjustment configuration information includes: one or more of the number of pulses, pulse width, and pulse shape included in the adjustment configuration information. For ease of explanation, the pulse shape included in the adjustment configuration information and the predetermined condition that the phase noise does not exceed -40dB / Hz are taken as an example, and the signal processing method provided in the embodiments of the present application should not be limited thereto.

[0087] Step 704: Output corresponding configuration information.

[0088] Combination Figure 8 As shown, the control device includes a processing circuit that outputs corresponding configuration information. Specifically, the control device includes a processing circuit that is used to output corresponding configuration information to the control circuit.

[0089] According to step 701 and step 702, the second moment control device can obtain the first detection signal corresponding to the first modulated optical signal and the phase noise of the first detection signal through the processing circuit. Combined with step 704, if the phase noise of the first detection signal does not exceed -40dB / Hz, the first configuration information is output. If the phase noise of the first detection signal still exceeds -40dB / Hz, step 703 is continued to be executed, that is, if the phase noise of the first detection signal still exceeds -40dB / Hz, the pulse shape contained in the first configuration information is continued to be adjusted to generate the second configuration information. Among them, the pulse shape contained in the second configuration is different from the pulse shape contained in the first configuration information.

[0090] Then, the above-mentioned signal processing method can judge whether the characteristic parameter meets the predetermined condition according to the characteristic parameter of the acquired detection signal, thereby generating corresponding configuration information and corresponding modulated electrical signal. Of course, since the above-mentioned characteristic parameters include phase noise, signal-to-noise ratio or dynamic range, it is possible to judge according to different characteristic parameters and the predetermined conditions corresponding to the characteristic parameters, adjust the configuration information of the detection signal, and generate new configuration information. In this way, the pulse shape (or pulse width, number of pulses) included in the optical signal generated corresponding to the generated configuration information is different, and the optical signal can realize the detection of more types of optical fiber sensing systems. For example, based on the new configuration information including more pulses, the corresponding optical signal generated will include more pulses, and the optical signal can realize the detection of optical fiber sensing systems with wider system bandwidth. Then, the control device in this scheme generates new configuration information by continuously adjusting the configuration values ​​included in the configuration information according to multiple judgments on the characteristic parameters and the predetermined conditions, so as to realize higher-precision detection of different optical fiber sensing systems.

[0091] For a predetermined condition, the signal processing method provided in the embodiment of the present application can adjust the pulse shape included in the configuration information so that the generated configuration information meets the predetermined condition while ensuring the transmission performance of the optical fiber sensing system. Fig. 9 As shown, an embodiment of the present application provides a schematic diagram of configuration information. Fig. 9 As shown in (1), the horizontal axis is time, the unit is microsecond (μs), the vertical axis is frequency, the unit is megahertz (MHz), within the period T = 250μs, there are two pulses with frequencies of 60MHz and -10MHz (corresponding to a frequency interval of 70MHz), that is, the number of pulses is 2. If the pulse width and the number of pulses are fixed within a certain time range, the frequency interval between the pulse signals is different, and the corresponding system bandwidth is also different. Combined with Fig. 9 As shown in (2), the horizontal axis is time, the unit is microsecond (μs), and the vertical axis is amplitude. For a pulse with a time length of t=125μs, the duration of the maximum amplitude is 100 nanoseconds, that is, the pulse width is 100ns. In this way, the configuration information includes the number of pulses as 2 and the pulse width as 100ns. Through the signal processing method described in steps 602-603, the corresponding modulated optical signal can be generated based on the above configuration information. Combined with Fig. 9 As shown in (3), through the signal processing method described in step 701-step 702, the phase noise of the detection signal corresponding to different pulse shapes can be obtained, wherein the horizontal axis is the pulse shape, the vertical axis is the phase noise, and the unit is decibel per hertz (dB / Hz). Specifically, the phase noise of the detection signal with a rectangular pulse shape is -5.5dB / Hz, the phase noise of the detection signal with a Hamming pulse shape is -11.5dB / Hz, the phase noise of the detection signal with a Hanning pulse shape is -10dB / Hz, the phase noise of the detection signal with a Blackman pulse shape is -5dB / Hz, the phase noise of the detection signal with a Kaiser pulse shape is -0.5dB / Hz, and the phase noise of the detection signal with a Gaussian pulse shape is -15.5dB / Hz. Then, when the predetermined condition requires the phase noise to be -14dB / Hz, the pulse shape adopts a Gaussian shape to make the phase noise level meet the predetermined condition and be the lowest, and the transmission performance of the optical fiber sensing system is the best.

[0092] It is not difficult to understand that Fig. 9 It is only a possible application scenario of the signal processing method described in the embodiment of the present application, and the embodiment of the present application should not be limited thereto. In a possible implementation, through the signal processing method described in the embodiment of the present application, other characteristic parameters (such as signal-to-noise ratio) of the detection signal corresponding to different pulse widths, pulse numbers and even frequency intervals can also be obtained.

[0093] Based on the above, for a certain predetermined condition, the signal processing method provided in the embodiment of the present application can also adjust the frequency interval so that the generated configuration information meets the predetermined condition while ensuring the transmission performance of the optical fiber sensing system. Fig.10 As shown, the embodiment of the present application also provides a schematic diagram of configuration information. Fig.10 As shown in (1), the horizontal axis is time, the unit is microsecond (μs), the vertical axis is frequency, the unit is megahertz (MHz), including two pulse signals, and the frequency interval between the pulse signals is unknown. Fig.10 As shown in (2), the horizontal axis is time, the unit is microsecond (μs), and the vertical axis is amplitude. For a pulse with a time length of t=125μs marked in the figure, the duration of the maximum amplitude is 100 nanoseconds, that is, the pulse width is 100ns. In this way, the configuration information includes a pulse width of 100ns and a pulse shape of a rectangle. Through the signal processing method described in steps 602-603, the corresponding modulated optical signal can be generated based on the above configuration information. Combined with Fig.10 As shown in (3), through the signal processing method described in step 701-step 702, the phase noise of the detection signal corresponding to different frequency intervals can be obtained, wherein the horizontal axis is the frequency interval, the unit is megahertz (MHz), and the vertical axis is the phase noise, the unit is decibel per hertz (dB / Hz). Specifically, the phase noise of the detection signal with a frequency interval of 10MHz is -1.5dB, the phase noise of the detection signal with an interval of 20MHz is -4dB, the phase noise of the detection signal with an interval of 50MHz is -7.5dB, the phase noise of the detection signal with an interval of 75MHz is -11dB, the phase noise of the detection signal with an interval of 125MHz is -12dB, and the phase noise of the detection signal with an interval of 150MHz is -11.5dB. Then, when the phase noise corresponding to the interval of 125MHz is -12dB, the phase noise level meets the predetermined conditions and is the lowest.

[0094] It is not difficult to understand that Fig.10 It is only a possible application scenario of the signal processing method described in the embodiment of the present application, and the embodiment of the present application should not be limited thereto. In a possible implementation, through the signal processing method described in the embodiment of the present application, other characteristic parameters (such as dynamic range) of the detection signal corresponding to different pulse widths, pulse shapes and pulse numbers can also be obtained.

[0095] Dynamic range is a key indicator in the OTDR system, and the dynamic range is defined as the difference between the root mean square (RMS) of the effective optical fiber signal and the RMS of the background noise. Since longer measurements can make it take longer to take the average value, the dynamic range of the OTDR system's measurement results will be better. Therefore, the same detection is usually repeated many times so that the OTDR can obtain the average value of multiple detections, thereby improving the dynamic range of the OTDR system. Generally speaking, the time required for detection can be reduced by adopting FDM technology, that is, FDM technology can make the configuration information include multiple pulse numbers. In this way, in one detection, the OTDR can generate and send an optical signal including multiple pulses based on the configuration information including multiple pulse numbers. Exemplarily, refer to Fig.11 As shown, the present application provides a schematic diagram of an OTDR system. Fig.11 As shown in (1), the OTDR using FDM technology is connected to the optical fiber to be tested. Fig.11 As shown in (2), the configuration information corresponding to the optical signal including multiple pulse numbers is shown, wherein the horizontal axis is time and the vertical axis is amplitude. Fig.11 As shown in (3), it shows that OTDR is Fig.11 Schematic diagram of detecting the optical signal shown in (1), wherein the horizontal axis is time and the vertical axis is amplitude.

[0096] The signal processing method provided in the embodiment of the present application can detect optical signals corresponding to different pulse numbers, obtain the dynamic range corresponding to the OTDR system and the increased value of the dynamic range of the OTDR system. Fig.12 As shown, the horizontal axis is the number of pulses, in units of pieces, and the vertical axis is the dynamic range increase, in decibels (dB). When the number of pulses is 2, the dynamic range increase of the OTDR system is the smallest, which is 0.5dB; when the number of pulses is 9, the dynamic range increase of the OTDR system is the largest, which is 4.5dB. It is not difficult to see that the larger the number of pulses, the greater the dynamic range increase of the OTDR system. For example, if the dynamic range of the OTDR system needs to be increased by 2dB, the number of pulses can be adjusted to 3 accordingly.

[0097] Therefore, through the signal processing method provided in the embodiment of the present application, the dynamic range corresponding to different numbers of pulses can be obtained by detection, thereby obtaining the corresponding relationship between the number of pulses and the increase in dynamic range. Based on the above embodiment, the embodiment of the present application can increase the dynamic range of the OTDR system by increasing the number of pulses, so that the dynamic range of the OTDR system increases accordingly.

[0098] Based on the above, due to the possibility of crosstalk between different pulses, the tail end signal of the fiber optic sensing system using FDM may not be recovered. Figure 9-12 As described above, the signal processing method provided in the embodiment of the present application can adjust the configuration values ​​such as the number of pulses and pulse shape according to the detection signal without manual analysis, so that the system bandwidth of the optical fiber sensing system is improved, the time consumption is shortened, and the transmission efficiency of the optical fiber sensing system is improved.

[0099] Exemplarily, the embodiments of the present application further provide a light detection system. Specifically, the light detection system includes: a laser, a light modulator, a receiving circuit, and a control device as described in the embodiments of the present application (refer to Figure 6 The control device 40 shown in the figure) wherein the optical modulator couples the laser and the optical fiber, and the receiving circuit couples the laser and the optical fiber; the receiving circuit is used to receive the carrier optical signal output by the laser and the detection optical signal output by the optical fiber, and outputs the detection signal in response to the carrier optical signal and the detection optical signal.

[0100] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in a claim. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0101] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A control device, characterized in that: Used in an optical detection system, the optical detection system comprising a laser, an optical modulator and a receiving circuit; the optical modulator is coupled to the laser and the optical fiber, and the receiving circuit is coupled to the laser and the optical fiber; the receiving circuit is used to receive a carrier optical signal output by the laser and a first detection optical signal output by the optical fiber, and output a first detection signal in response to the carrier optical signal and the first detection optical signal; The control device comprises: a processing circuit and a control circuit; The processing circuit is configured to generate first configuration information based on the first detection signal output by the receiving circuit, and send the first configuration information to the control circuit; The control circuit is used to generate a first modulated electrical signal based on the first configuration information, and send the first modulated electrical signal to the optical modulator, and the optical modulator is specifically used to modulate the first modulated electrical signal to the carrier optical signal to generate a first modulated optical signal, wherein the first configuration information includes at least one of the following configuration values ​​of the first modulated optical signal: number of pulses, pulse width, and pulse shape.

2. The control device according to claim 1, characterized in that: The processing circuit is further used to generate initial configuration information; and send the initial configuration information to the control circuit; The control circuit is used to generate an initial modulated electrical signal based on the initial configuration information, and send the initial modulated electrical signal to the optical modulator, and the optical modulator is specifically used to modulate the initial modulated electrical signal to the carrier optical signal to generate an initial modulated optical signal, wherein the initial configuration information includes at least one of the following configuration values ​​of the initial modulated optical signal: the number of pulses, the pulse width, and the pulse shape; The optical fiber is used to generate a first detection optical signal based on the initial modulated optical signal. The receiving circuit receives the carrier optical signal output by the laser and the first detection optical signal output by the optical fiber, and outputs a first detection signal in response to the carrier optical signal and the first detection optical signal.

3. The control device according to claim 2, characterized in that: The processing circuit specifically obtains characteristic parameters of the first detection signal, and the characteristic parameters include any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the first detection signal do not meet predetermined conditions, the first configuration information is generated, wherein the pulse shape included in the first configuration information is different from the pulse shape included in the initial configuration information, and / or the pulse width included in the first configuration information is different from the pulse width included in the initial configuration information.

4. The control device according to claim 1 or 3, characterized in that: The optical fiber is used to generate a second detection optical signal based on the first modulated optical signal; the receiving circuit is used to receive the carrier optical signal output by the laser and the second detection optical signal output by the optical fiber, and output a second detection signal in response to the carrier optical signal and the second detection optical signal; The processing circuit is further configured to obtain a characteristic parameter of the second detection signal based on the second detection signal output by the receiving circuit, wherein the characteristic parameter includes any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the second detection signal do not meet the predetermined conditions, generate second configuration information, wherein the pulse shape contained in the second configuration information is different from the pulse shape contained in the first configuration information, and / or the pulse width contained in the second configuration information is different from the pulse width contained in the first configuration information; send the second configuration information to the control circuit.

5. The control device according to claim 4, characterized in that: The processing circuit is further used to obtain a characteristic parameter of the second detection signal based on the second detection signal output by the receiving circuit, wherein the characteristic parameter includes any one of the following: signal-to-noise ratio, phase noise, and dynamic range; If the characteristic parameter of the second detection signal meets a predetermined condition, the first configuration information is sent to the control circuit.

6. The control device according to claim 2, characterized in that: The processing circuit specifically obtains characteristic parameters of the first detection signal, and the characteristic parameters include any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the first detection signal meet predetermined conditions, the first configuration information is generated, wherein the number of pulses included in the first configuration information is greater than the number of pulses included in the initial configuration information.

7. The control device according to claim 1 or 6, characterized in that: The optical fiber is used to generate a second detection optical signal based on the first modulated optical signal; the receiving circuit is used to receive the carrier optical signal output by the laser and the second detection optical signal output by the optical fiber, and output a second detection signal in response to the carrier optical signal and the second detection optical signal; The processing circuit is further configured to obtain a characteristic parameter of the second detection signal based on the second detection signal output by the receiving circuit, wherein the characteristic parameter includes any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the second detection signal meet the predetermined conditions, generating the second configuration information, wherein the number of pulses included in the second configuration information is greater than the number of pulses included in the first configuration information; The second configuration information is sent to the control circuit.

8. A signal processing method, characterized in that: Used in an optical detection system, the optical detection system comprising a laser, an optical modulator and a receiving circuit; the optical modulator couples the laser and the optical fiber, the receiving circuit couples the laser and the optical fiber; the receiving circuit is used to receive a carrier optical signal output by the laser and a first detection optical signal output by the optical fiber, and output a first detection signal in response to the carrier optical signal and the first detection optical signal; The signal processing method comprises: generating first configuration information based on the first detection signal; A first modulated electrical signal is generated based on the first configuration information, and the first modulated electrical signal is sent to the optical modulator, wherein the optical modulator is specifically used to modulate the first modulated electrical signal onto the carrier optical signal to generate the first modulated optical signal, wherein the first configuration information includes at least one of the following configuration values ​​of the first modulated optical signal: number of pulses, pulse width, and pulse shape.

9. The signal processing method according to claim 8, characterized in that: The step of generating the first configuration information based on the first detection signal also includes: Generate initial configuration information; generating an initial modulated electrical signal based on the initial configuration information, and sending the initial modulated electrical signal to the optical modulator, wherein the optical modulator is specifically configured to modulate the initial modulated electrical signal onto the carrier optical signal to generate an initial modulated optical signal, wherein the initial configuration information includes at least one of the following configuration values ​​of the initial modulated optical signal: the number of pulses, the pulse width, and the pulse shape; The optical fiber is used to generate a first detection optical signal based on the initial modulated optical signal. The receiving circuit receives the carrier optical signal output by the laser and the first detection optical signal output by the optical fiber, and outputs a first detection signal in response to the carrier optical signal and the first detection optical signal.

10. The signal processing method according to claim 9, characterized in that: Acquire a characteristic parameter of the first detection signal, where the characteristic parameter includes any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the first detection signal do not meet the predetermined conditions, the first configuration information is generated, wherein the pulse shape contained in the first configuration information is different from the pulse shape contained in the initial configuration information, and / or the pulse width contained in the first configuration information is different from the pulse width contained in the initial configuration information.

11. The signal processing method according to claim 8 or 10, characterized in that: The optical fiber is used to generate a second detection optical signal based on the first modulated optical signal; the receiving circuit is used to receive the carrier optical signal output by the laser and the second detection optical signal output by the optical fiber, and output a second detection signal in response to the carrier optical signal and the second detection optical signal; Acquire a characteristic parameter of the second detection signal, where the characteristic parameter includes any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the second detection signal do not meet the predetermined conditions, second configuration information is generated, wherein the pulse shape contained in the second configuration information is different from the pulse shape contained in the first configuration information, and / or the pulse width contained in the second configuration information is different from the pulse width contained in the first configuration information.

12. The signal processing method according to claim 11, characterized in that: Acquire characteristic parameters of the second detection signal, wherein the characteristic parameters include any one of the following: signal-to-noise ratio, phase noise, and dynamic range; If the characteristic parameter of the second detection signal meets a predetermined condition, the first configuration information is still generated.

13. The signal processing method according to claim 9, characterized in that: Acquire a characteristic parameter of the first detection signal, where the characteristic parameter includes any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the first detection signal meet predetermined conditions, the first configuration information is generated, wherein the number of pulses included in the first configuration information is greater than the number of pulses included in the initial configuration information.

14. The signal processing method according to claim 8 or 13, characterized in that: The optical fiber is used to generate a second detection optical signal based on the first modulated optical signal; the receiving circuit is used to receive the carrier optical signal output by the laser and the second detection optical signal output by the optical fiber, and output a second detection signal in response to the carrier optical signal and the second detection optical signal; Acquire a characteristic parameter of the second detection signal, where the characteristic parameter includes any one of the following: signal-to-noise ratio, phase noise and dynamic range; if the characteristic parameters of the second detection signal meet predetermined conditions, the second configuration information is generated, wherein the number of pulses included in the second configuration information is greater than the number of pulses included in the first configuration information.

15. A light detection system, characterized in that: The optical detection system comprises: a laser, an optical modulator and a receiving circuit; The optical modulator is coupled to the laser and the optical fiber, and the receiving circuit is coupled to the laser and the optical fiber; the receiving circuit is used to receive the carrier optical signal output by the laser and the detection optical signal output by the optical fiber, and output a detection signal in response to the carrier optical signal and the detection optical signal; And a control device as described in any one of claims 1 to 7.

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