Intelligent carpet with multi-dimensional perception

Abstract

The application discloses a kind of multi-dimensional perception intelligent carpets, including Brillouin time domain analysis system chip, sensing optical fiber carpet and processing module, the sensing optical fiber carpet is provided with reticular optical fiber, the Brillouin time domain analysis system chip is connected the sensing optical fiber carpet, the sensing optical fiber carpet connects the processing module;Wherein, the Brillouin time domain analysis system chip is used to generate pump light and probe light;The sensing optical fiber carpet is used to generate feedback signal according to the pump light and the probe light of incidence;The processing module is used to determine probe information according to the feedback signal.The embodiment of the application is convenient for device integration, reduces equipment cost, and can be widely applied in detection technical field.

Description

Technical Field

[0001] This invention relates to the field of detection technology, and more particularly to a multi-dimensional sensing smart carpet. Background Technology

[0002] Currently, most electrical sensors in use are point sensors, which involve complex cable installations and are susceptible to electromagnetic interference. In contrast to traditional electronic sensors, optical fibers serve as both information transmission channels and sensing units, enabling long-distance and distributed sensing. Furthermore, since most optical fibers are made of quartz, they are lightweight, small in size, and easy to lay. Fiber optic sensing also possesses anti-interference and corrosion-resistant properties. Finally, fiber optic sensing offers a wider measurement range, higher sensitivity, and higher resolution.

[0003] In recent years, distributed fiber optic sensing has developed rapidly. Compared with other sensing principles, distributed Brillouin fiber optic sensing technology has the performance of measuring distances of up to hundreds of kilometers and monitoring points of up to millions. Moreover, given a sufficiently large frequency measurement range, the maximum measurable strain or temperature can reach the limit that the fiber can withstand. By introducing high-frequency signal generator technology, Brillouin fiber optic sensing systems can achieve dynamic measurements at the kHz level, realizing long-distance, fast, and high spatial resolution stress and temperature measurements.

[0004] The shortcomings of existing technologies / the technical problems to be solved by this invention: Brillouin fiber optic sensing and measurement systems can achieve dynamic measurements, but they mainly rely on high-bandwidth signal generators. The bandwidth requirement of the signal generator depends on the magnitude of the Brillouin frequency shift in the fiber, typically requiring around 11 GHz. Such instruments are bulky, making integration difficult and significantly increasing equipment costs. Furthermore, the system resolution is limited by pulse width constraints, not less than a phonon lifetime of 10 ns, corresponding to a system resolution of 1 m, which restricts its application scenarios. Summary of the Invention

[0005] In view of this, in order to solve one of the above problems, the purpose of this invention is to provide a multi-dimensional sensing smart carpet that facilitates device integration, reduces equipment costs, and improves resolution.

[0006] This invention provides a multi-dimensional sensing smart carpet, including a Brillouin time-domain analysis system chip, a sensing fiber optic carpet, and a processing module. The sensing fiber optic carpet is provided with a mesh of optical fibers. The Brillouin time-domain analysis system chip is connected to the sensing fiber optic carpet, and the sensing fiber optic carpet is connected to the processing module.

[0007] The Brillouin time-domain analysis system chip is used to generate pump light and probe light;

[0008] The sensing fiber carpet is used to generate a feedback signal based on the incident pump light and the probe light;

[0009] The processing module is used to determine the detection information based on the feedback signal.

[0010] Optionally, the Brillouin time-domain analysis system chip includes a frequency-modulated continuous wave laser, a beam splitter, a first optical path, and a second optical path. The light emitted by the frequency-modulated continuous wave laser is split into two paths by the beam splitter. One path is modulated into a pulsed laser as pump light through the first optical path, and the other path is frequency-shifted through the second optical path to obtain probe light.

[0011] Optionally, the first optical path includes a first electro-optic modulator, a first amplifier, and a circulator connected in sequence.

[0012] Optionally, the second optical path includes a second electro-optic modulator, a filter, a second amplifier, and an optical isolator connected in sequence.

[0013] Optionally, the frequency-modulated continuous wave laser includes a semiconductor amplifier and a micro-ring modulator, wherein the micro-ring modulator is used to scan the laser at a preset frequency according to the modulation voltage.

[0014] Optionally, the modulation voltage includes a linear function, the linear scan region is a first preset time, and a second preset time is set as a spare time between the linear periods.

[0015] Optionally, the platform material of the Brillouin time-domain analysis system chip includes any one of lithium niobate, silicon-on-insulator, or silicon nitride.

[0016] Optionally, the mesh optical fibers are laid crosswise along two mutually perpendicular directions.

[0017] Implementing this embodiment of the invention offers the following advantages: The multi-dimensional sensing smart carpet in this embodiment includes a Brillouin time-domain analysis system chip, a sensing fiber optic carpet, and a processing module. The sensing fiber optic carpet is equipped with a mesh of optical fibers. The Brillouin time-domain analysis system chip is connected to the sensing fiber optic carpet, and the sensing fiber optic carpet is connected to the processing module. The Brillouin time-domain analysis system chip generates pump light and probe light. The sensing fiber optic carpet generates feedback signals based on the incident pump light and probe light. The processing module determines the detection information based on the feedback signals. By simultaneously generating pump light and probe light through the Brillouin time-domain analysis system chip, it replaces the traditional fast high-frequency signal generator to achieve rapid frequency conversion. Integrating the device onto the Brillouin time-domain analysis system chip reduces equipment costs. The smart carpet, through the mesh laying of optical fibers, can change the spatial resolution of the system by altering the fiber spacing, improving the system resolution to the millimeter level, and can be arbitrarily spliced ​​and expanded. Attached Figure Description

[0018] Figure 1 This is a structural block diagram of a multi-dimensional sensing smart carpet provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the transmission of pump light and probe light provided in an embodiment of the present invention;

[0020] Figure 3 This is a structural block diagram of a Brillouin time-domain analysis system chip provided in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of a laser linear scanning method provided in an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of another multi-dimensional sensing smart carpet provided in an embodiment of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0024] See Figure 1 This invention provides a multi-dimensional sensing smart carpet, including a Brillouin time-domain analysis system chip, a sensing fiber optic carpet, and a processing module. The sensing fiber optic carpet is equipped with a mesh of optical fibers. The Brillouin time-domain analysis system chip is connected to the sensing fiber optic carpet, and the sensing fiber optic carpet is connected to the processing module.

[0025] Brillouin time-domain analysis system chip, used to generate pump light and probe light;

[0026] A sensing fiber optic carpet is used to generate feedback signals based on incident pump and probe light.

[0027] The processing module is used to determine the detection information based on the feedback signal.

[0028] It should be noted that the feedback signal refers to the signal formed after the pump light and probe light are transmitted through the optical fiber; the detection information refers to the information to be detected, including but not limited to temperature information, stress information, or velocity information. The pump light and probe light generated by the Brillouin time-domain analysis system chip are incident on the optical fiber of the sensing fiber carpet; the pump light and probe light produce Brillouin scattering in the optical fiber, generating different feedback signals when the external environment is different; after receiving the feedback signal, the processing module processes and analyzes the feedback signal to obtain the detection information.

[0029] The main principle for detecting stress and velocity sensing information in this invention is the Brillouin scattering effect of optical fiber. The principle of scattering-type distributed optical fiber sensing is to demodulate external temperature or strain information by utilizing changes in the intensity or frequency shift of the scattered signal in the optical fiber. The frequency of the scattered light relative to the incident light is called Stokes light in the low-frequency component and anti-Stokes light in the high-frequency component. The main types of scattered light signals include Rayleigh scattering, Rayleigh wing scattering, Brillouin scattering, and Raman scattering.

[0030] The Brillouin frequency shift of backscattering in optical fibers is related to the effective refractive index and the velocity of sound in the fiber. When external environmental factors cause changes in the effective refractive index or the velocity of sound in the fiber, the corresponding Brillouin frequency shift will also change. Therefore, distributed sensing of external environmental factors such as strain and temperature along the fiber can be achieved by measuring the Brillouin frequency shift. This solution's sensing chip is based on the principle of stimulated Brillouin scattering and employs a Brillouin optical time-domain analysis system, implemented on a lithium niobate integrated optical platform.

[0031] See Figure 2 The main principle of the Brillouin time-domain analysis system chip is that the pump light (P1) and the probe light (P2) undergo stimulated Brillouin scattering in the fiber under test. The scattered light is collected by the detector. The pump light is usually a pulsed light, and the probe light is a continuous light that is frequency-shifted and swept by the modulator.

[0032] Implementing this embodiment of the invention offers the following advantages: The multi-dimensional sensing smart carpet in this embodiment includes a Brillouin time-domain analysis system chip, a sensing fiber optic carpet, and a processing module. The sensing fiber optic carpet is equipped with a mesh of optical fibers. The Brillouin time-domain analysis system chip is connected to the sensing fiber optic carpet, and the sensing fiber optic carpet is connected to the processing module. The Brillouin time-domain analysis system chip generates pump light and probe light. The sensing fiber optic carpet generates feedback signals based on the incident pump light and probe light. The processing module determines the detection information based on the feedback signals. By simultaneously generating pump light and probe light through the Brillouin time-domain analysis system chip, it replaces the traditional fast high-frequency signal generator to achieve rapid frequency conversion. Integrating the device onto the Brillouin time-domain analysis system chip reduces equipment costs. The smart carpet, through the mesh laying of optical fibers, can change the spatial resolution of the system by altering the fiber spacing, improving the system resolution to the millimeter level, and can be arbitrarily spliced ​​and expanded.

[0033] Optionally, the Brillouin time-domain analysis system chip includes a frequency-modulated continuous wave laser, a beam splitter, a first optical path, and a second optical path. The light emitted by the frequency-modulated continuous wave laser is split into two paths by the beam splitter. One path is modulated into a pulsed laser as pump light through the first optical path, and the other path is frequency-shifted through the second optical path to obtain the probe light.

[0034] See Figure 3A frequency-modulated continuous wave laser can generate pump light and probe light by modulating at different time periods. Then, it is split into two beams by a beam splitter. One beam is modulated into a pulsed laser as pump light through the first optical path, and the other beam is frequency-shifted through the second optical path to obtain probe light.

[0035] Optionally, the frequency-modulated continuous wave laser includes a semiconductor amplifier and a microring modulator, the microring modulator being used to scan the laser at a preset frequency according to the modulation voltage.

[0036] A semiconductor amplifier is used to generate laser light, which is then modulated by a micro-ring modulator to achieve a preset frequency scan of the laser.

[0037] Optionally, the first optical path includes a first electro-optic modulator, a first amplifier, and a circulator connected in sequence.

[0038] The first electro-optic modulator is used to generate a pulse modulation signal, the first amplifier is used to amplify the modulated signal, and the amplified signal is output after passing through a circulator.

[0039] Optionally, the second optical path includes a second electro-optic modulator, a filter, a second amplifier, and an optical isolator connected in sequence.

[0040] The second electro-optic modulator is used to shift the frequency of the signal, the filter is used to filter the sidebands outside the center wavelength, the second amplifier is used to amplify the filtered signal, and the optical isolator is used to isolate the light transmitted in the opposite direction.

[0041] Optionally, the modulation voltage includes a linear function, the linear scan region is a first preset time, and a second preset time is set as a spare time between the linear periods.

[0042] It should be noted that the first preset time and the second preset time are determined according to the actual application, and this embodiment does not impose specific restrictions.

[0043] See Figure 4 In one specific embodiment, the modulation voltage of the laser in the frequency-modulated continuous-wave laser chip is a linear function, the linear sweep region is 20 ns, and the sweep speed is set to 15 MHz / ns to achieve frequency scanning of the light source from 0 to 300 MHz. A 10 ns idle time is set between each linear cycle. During the time without sweeping, the laser is modulated into pulsed light as pump light, and during the linear sweep region, it is modulated into probe light. The frequency-modulated continuous-wave laser chip can generate pump light and probe light, thereby realizing the generation of stimulated Brillouin signal in the fiber under test.

[0044] Optionally, the platform material of the Brillouin time-domain analysis system chip includes any one of lithium niobate, silicon-on-insulator, or silicon nitride.

[0045] The platform materials of the Brillouin time-domain analysis system chip include, but are not limited to, lithium niobate, silicon-on-insulator, or silicon nitride. The Brillouin time-domain analysis system chip integrates light-emitting materials on the platform.

[0046] Lithium niobate is an important photonic material with excellent electro-optic coefficients and a wide optical transparency window, making it widely used in photonic devices such as optical modulators, second harmonic generators, and acoustic transducers. However, lithium niobate is a dielectric material and cannot effectively generate and detect photons. In optical communication systems, electrically pumped semiconductor lasers based on InP and GaAs materials have been widely used. Therefore, leveraging the advantages of different material platforms, III-V semiconductors are heterogeneously or hybridized with lithium niobate.

[0047] Fiber optic sensing systems often contain many active and passive components that are incompatible for integration on the same platform, such as optical amplifiers and photodetectors, which are typically fabricated using group III-V materials. Compared to traditional Brillouin optical time-domain analysis techniques, the fiber optic sensing chip in this invention integrates active and passive components made of group III-V materials, significantly reducing device size. System integration also reduces system losses and improves device performance. Sensing measurements can be achieved simply by connecting a low-frequency microwave signal.

[0048] Optionally, the mesh fiber optic cable is laid in a crisscross pattern along two mutually perpendicular directions.

[0049] The specific laying method of the mesh fiber optic cable is determined according to the actual application, and this embodiment does not impose specific restrictions. Laying the mesh fiber optic cable in two mutually perpendicular directions can reduce the amount of calculation.

[0050] Traditional Brillouin fiber optic sensing systems rely on pulse length for spatial resolution. However, due to the lifetime of fiber phonons, the system pulse width must be at least 10 ns, resulting in a minimum spatial resolution of 1 m. This limits the application of Brillouin sensing systems in high spatial resolution scenarios. Therefore, overcoming the pulse width limitation and improving the system's spatial resolution is crucial.

[0051] This solution employs a mesh-like fiber optic cable layout, adjusting the system's spatial resolution by controlling the fiber spacing. The detailed solution is attached. Figure 5As shown in the magnified view of the optical fiber in the sensing system, the optical fiber under test is laid interwoven in both the x and y directions. When strain occurs at a certain point, both directions of the fiber will be affected by stress, resulting in a change in the Brillouin frequency shift. The reflected signal will show abrupt changes in the Brillouin frequency shift of two or more fiber segments. These abrupt changes are mapped to the positions of the fiber segments in both directions according to their length information; the intersection point is the location of the stress. Therefore, the spatial resolution of the system can be changed by altering the fiber spacing. Reducing the fiber spacing can improve the spatial resolution; for example, laying the fiber with a 10mm spacing can achieve a system resolution of 10mm. This embodiment of the invention can achieve a very small (millimeter-level) spatial resolution without complex processing of the measurement results.

[0052] In one specific embodiment, optical fibers are used as sensors. These fibers are placed between two layers of carpet to form a sensing carpet, which can be freely spliced ​​together to achieve distributed sensing on a planar surface. The carpet can be spliced ​​and expanded according to the size of the target being sensed, making it highly portable and flexible.

[0053] The processing module can obtain changes in the temporal signal within the optical fiber and determine the location of the corresponding stress point based on the temporal position. The spacing and length of the optical fiber installation for each carpet are recorded in the processing module. The optical signal acquired through the sensing fiber is a one-dimensional temporal signal. Different time points correspond to different one-dimensional positions within the fiber. Strain at a certain point causes a frequency shift in the Brillouin center wavelength at one or more ends of the fiber in the temporal signal. The processing module establishes different positional models for carpets with different fiber installations, processes the obtained Brillouin scattering signals, and assigns different temporal positions to different spatial locations. The rate of stress change can also be obtained based on the rate of change of the location point, thus achieving intelligent sensing of stress and velocity.

[0054] This system, comprised of a Brillouin time-domain analysis system chip, a fiber optic sensing mat, and a processing module, enables rapid, high-resolution, and highly sensitive real-time intelligent sensing of stress, temperature, and other parameters. It can be used not only as a portable fiber optic sensing mat but also embedded in floors, roads, and bridges. Fiber optics, as a sensor, offer the advantage of easy connectivity; fiber optic networks can be freely spliced ​​and expanded, thus limiting the sensing range. The stress and temperature sensitivity of this invention allows for applications in motion monitoring, providing real-time stress changes during races or training sessions. It can also be used on racetracks or airports to monitor the stress exerted by race cars or aircraft on the ground. Due to the integrated system, the sensor chip is very small and lightweight, enhancing its application in spacecraft.

[0055] In one specific embodiment, the multidimensional sensing smart carpet includes a Brillouin time-domain analysis system chip (1-1), a sensing fiber carpet (1-2), and a processing module (1-3). The Brillouin time-domain analysis system chip (1-1) includes a frequency-modulated continuous wave laser (1-1-1), a first modulator (1-1-2), a first amplifier (1-1-3), a circulator (1-1-4), a second modulator (1-1-5), a filter (1-1-6), a second amplifier (1-1-7), and an optical isolator (1-1-8). The frequency-modulated continuous wave laser (1-1-1) includes a semiconductor amplifier (1-1-10), a phase modulator (1-1-11), a micro-ring modulator (1-1-12), and a tunable loop reflector (1-1-13). The sensing fiber carpet (1-2) is provided with a mesh of optical fibers (1-2-1).

[0056] In one specific embodiment, a frequency-modulated continuous-wave laser is used as the light source, modulated by an arbitrary waveform generator. The wavelength of the frequency-modulated continuous-wave laser is set to 1550 nm, the frequency sweep range is 300 MHz, the frequency sweep speed is 15 MHz / ns, and the sweep idle interval is 10 ns. This light source is heterogeneously or hybrid-integrated on a lithium niobate platform and split into two paths by an on-chip 50:50 beam splitter. The first path of light is modulated into pulsed light as pump light by an electro-optic modulator. The pulse modulation function is generated by the arbitrary waveform generator and synchronized with the laser modulation function to ensure that the light is modulated into a pulse during the 1 ns idle time of the laser. The pulse length is 10 ns and the duty cycle is 33%. The pulsed light is amplified by an amplifier, which is a heterogeneously integrated III-V semiconductor optical amplifier on the lithium niobate platform, and then leaves the chip and enters the optical fiber after passing through a circulator. The second beam is frequency-shifted by 10.6 GHz by an electro-optic modulator operating at the carrier suppression point, changing the frequency from 0–300 MHz to a high-frequency scan of 10.6–10.9 GHz, near the Brillouin shift of the fiber, thus frequency-shifting the continuous light. Then, it passes through a micro-ring filter to remove additional first-order sidebands. This filter has a bandwidth of 3 GHz, and the center wavelength is adjusted to filter out other sidebands. The light is then amplified to 100 mW by an optical amplifier before passing through an optical isolator and entering the fiber under test. The pump and probe beams generate stimulated Brillouin scattering signals within the fiber under test, which are detected and collected by a photodetector. A 1 km long polarization-maintaining fiber is selected as the fiber under test, laid sequentially in the x and y directions with a fiber spacing of 10 cm. The fiber is connected to the external fiber of the chip using a flange. The scattered signal in the fiber is detected by the photodetector and then transmitted to the processing module for processing. The stress location is analyzed to obtain the measurement results.

[0057] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A multi-dimensional sensing smart carpet, characterized in that, The system includes a Brillouin time-domain analysis system chip, a sensing fiber optic carpet, and a processing module. The sensing fiber optic carpet is provided with a mesh of optical fibers, which are laid crosswise in two mutually perpendicular directions. The Brillouin time-domain analysis system chip is connected to the sensing fiber optic carpet, and the sensing fiber optic carpet is connected to the processing module. The Brillouin time-domain analysis system chip is used to generate pump light and probe light. The Brillouin time-domain analysis system chip includes a frequency-modulated continuous-wave laser, a beam splitter, a first optical path, and a second optical path. The light emitted by the frequency-modulated continuous-wave laser is split into two paths by the beam splitter. One path is modulated into a pulsed laser as pump light through the first optical path, and the other path is frequency-shifted through the second optical path to obtain probe light. The frequency-modulated continuous-wave laser includes a semiconductor amplifier and a micro-ring modulator. The micro-ring modulator is used to scan the laser at a preset frequency according to the modulation voltage. The modulation voltage includes a linear function, with the linear scanning region being a first preset time, and a second preset time interval between the linear periods. The sensing fiber carpet is used to generate a feedback signal based on the incident pump light and the probe light; The processing module is used to determine the detection information based on the feedback signal; When strain occurs at a certain point, the optical fibers in both directions will be affected by stress, resulting in a change in the Brillouin frequency shift. The reflected signal will show abrupt changes in the Brillouin frequency shift of two or more optical fiber segments. These abrupt changes are mapped to the positions of the optical fibers in the two directions according to their length information. The intersection point is the location where stress is received. The spatial resolution of the system can be changed by changing the arrangement spacing of the optical fibers. If the optical fiber spacing is reduced, the spatial resolution can be improved.

2. The smart carpet according to claim 1, characterized in that, The first optical path includes a first electro-optic modulator, a first amplifier, and a circulator connected in sequence.

3. The smart carpet according to claim 1, characterized in that, The second optical path includes a second electro-optic modulator, a filter, a second amplifier, and an optical isolator connected in sequence.

4. The smart carpet according to any one of claims 1-3, characterized in that, The platform material of the Brillouin time-domain analysis system chip includes any one of lithium niobate, silicon-on-insulator, or silicon nitride.

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