Bank machine room temperature monitoring system and method based on weak fiber grating array

Abstract

The invention provides a bank machine room temperature monitoring system and method based on a weak fiber grating array. The method comprises the following steps: generating a plurality of access pulses with different emergent wavelengths; for each access pulse, each grating in the fiber grating array is reflected to form a reflected pulse; collecting each reflected pulse output by the fiber grating array to obtain spectral data of each grating and a reflection time difference corresponding to each piece of spectral data; sending each piece of spectral data and the corresponding reflection time difference to a processor; the processor performs Gaussian fitting on each piece of spectral data to obtain a reflection wavelength, and determines a grating corresponding to the spectral data based on a reflection time difference corresponding to each piece of spectral data; and monitoring the reflection wavelength change of the spectral data corresponding to each grating to obtain the temperature change condition of the bank machine room. In the scheme, the fiber grating array is used as a sensor, the external interference resistance is high, the accuracy is high, TDM and WDM technologies are adopted, the cost is reduced, and the accuracy is ensured.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and in particular to a bank computer room temperature monitoring system and method based on a weak optical fiber grating array. Background Art

[0002] As major banks deepen their digital transformation, the financial technology industry has become an indispensable part of banking business. As the cornerstone of technological development, the physical security of data center rooms is even more important. In order to ensure the normal environment of the computer room, it is often necessary to monitor the temperature and other information of the computer room in real time to prevent unknown risks.

[0003] At present, the monitoring system built by traditional electric sensors is commonly used for temperature monitoring in bank computer rooms. Due to the limitations of the working principle and manufacturing materials of traditional electric sensors, they have shortcomings such as easy corrosion and loss, and weak resistance to external interference. At the same time, in order to achieve high-accuracy monitoring, a large number of sensors need to be deployed on the six sides of the computer room, which will lead to a surge in the cost of building the monitoring system. If the density of sensor deployment is reduced to save costs, it will lead to problems such as insufficient system monitoring accuracy and untimely response. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a bank computer room temperature monitoring system and method based on a weak fiber grating array to achieve the purpose of improving the ability to resist external interference, reducing costs and ensuring accuracy.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] The embodiment of the present invention discloses a bank computer room temperature monitoring system based on a weak fiber grating array.

[0007] The system includes: a fiber grating array, a demodulation system and a processor; the fiber grating array is deployed on the surface of each wall in the bank's computer room, and the fiber grating array is composed of multiple gratings;

[0008] The demodulation system is used to generate a plurality of access pulses with different emission wavelengths; for each of the access pulses, send them to each grating in the fiber grating array; receive the reflected pulse reflected by each of the gratings in the fiber grating array, and demodulate each group of the reflected pulses to obtain a plurality of spectral data and corresponding reflection time differences; and send each of the spectral data and the corresponding reflection time differences to the processor;

[0009] The fiber grating array is used to output multiple groups of reflected pulses to the demodulation system; each group of reflected pulses is obtained by the corresponding grating reflecting the access pulses of different emission wavelengths;

[0010] The processor is used to perform Gaussian fitting on each spectral data to obtain the reflection wavelength, and determine the grating corresponding to the spectral data based on the reflection time difference corresponding to each spectral data; monitor the change of the reflection wavelength of the spectral data corresponding to each grating to obtain the temperature change of the bank room.

[0011] Preferably, the demodulation system comprises: a scanning laser, an SOA module, an EDFA module, an optical fiber circulator, a photodetector, a data acquisition card and a pulse generator;

[0012] The scanning laser is used to generate a plurality of optical signals with different emission wavelengths and output them to the SOA module;

[0013] The SOA module is used to modulate each of the optical signals using the pulse signal output by the pulse generator to obtain each access pulse to be amplified, and input each access pulse to be amplified into the EDFA module;

[0014] The EDFA module amplifies each access pulse to be amplified to obtain each access pulse, and inputs each access pulse into the optical fiber circulator;

[0015] The fiber circulator is used to send each access pulse to each grating in the fiber grating array; receive the reflected pulse reflected by each grating in the fiber grating array, and input each group of the reflected pulses into the photodetector;

[0016] The photoelectric detector is used to convert each group of the reflected pulses into individual electrical signals, and input each of the electrical signals into the data acquisition card;

[0017] The data acquisition card is used to perform acquisition and processing based on each of the electrical signals and the pulse signal output by the pulse generator to obtain a plurality of spectral data and corresponding reflection time differences; and send each of the spectral data and the corresponding reflection time difference to the processor.

[0018] Preferably, the processor is further used for:

[0019] Determine whether each of the spectral data is affected by crosstalk and shadow effects;

[0020] If so, for each spectral data affected by the crosstalk and the shadow effect, a layer-by-layer compensation algorithm is used to perform crosstalk suppression processing to obtain the processed spectral data.

[0021] Preferably, for each of the spectral data affected by the crosstalk and the shadow effect, a layer-by-layer compensation algorithm is used to perform crosstalk suppression processing to obtain the processed spectral data, specifically for:

[0022] Layering the gratings according to the central wavelengths corresponding to the gratings;

[0023] Calculate the first light intensity of the reflected pulses of each layer after the i-th layer reduced due to the access pulse being reflected by the i-th layer of the grating; i is a positive integer;

[0024] Calculate the second light intensity of the reflected pulse of the grating of the i-th layer after multiple first-order reflections and the reflected pulse of the i+1-th layer superimposed;

[0025] Accumulate each of the first light intensities and each of the second light intensities corresponding to the first i layers according to the time division multiplexing crosstalk generation principle to obtain an accumulation result;

[0026] For each spectral data affected by crosstalk in the i-th layer, crosstalk suppression is performed on the spectral data using the accumulated result to obtain the spectral data after crosstalk suppression;

[0027] The shadow effect compensation is calculated, and the spectrum data after the crosstalk suppression is compensated based on the shadow effect compensation to obtain the processed spectrum data.

[0028] Preferably, the processor is further used for:

[0029] Based on the temperature change of the bank computer room, a temperature change curve of each position in the bank computer room is generated.

[0030] Preferably, the system further comprises: a display;

[0031] The display is used to display the temperature change curve at each position.

[0032] The second aspect of the embodiment of the present invention discloses a bank computer room temperature monitoring method based on a weak fiber grating array, which is applied to any of the bank computer room temperature monitoring systems based on a weak fiber grating array disclosed in the first aspect of the embodiment of the present invention, and the method comprises:

[0033] Generate a plurality of access pulses with different emission wavelengths by using a demodulation system, and send each of the access pulses to each grating in the fiber grating array;

[0034] Using a demodulation system to receive the reflected pulses reflected by each grating in the fiber grating array, demodulating each group of the reflected pulses to obtain a plurality of spectrum data and corresponding reflection time differences, and sending each of the spectrum data and the corresponding reflection time differences to a processor; each group of the reflected pulses is obtained by the corresponding grating reflecting the access pulses of different emission wavelengths;

[0035] Using the processor to perform Gaussian fitting on each of the spectral data to obtain a reflection wavelength;

[0036] Determine the grating corresponding to the spectral data by using the processor and the reflection time difference corresponding to each spectral data;

[0037] The processor is used to monitor the change of the reflection wavelength of the spectral data corresponding to each grating to obtain the temperature change of the bank room.

[0038] Preferably, the demodulation system comprises: a scanning laser, an SOA module, an EDFA module, an optical fiber circulator, a photodetector, a data acquisition card and a pulse generator;

[0039] Accordingly, the demodulation system is used to generate a plurality of access pulses with different emission wavelengths, and each access pulse is sent to each grating in the fiber grating array, including:

[0040] The scanning laser is used to generate a plurality of optical signals with different emission wavelengths and output them to the SOA module. The SOA module uses the pulse signal output by the pulse generator to modulate each of the optical signals to obtain each access pulse to be amplified.

[0041] Inputting each access pulse to be amplified into the EDFA module for amplification processing to obtain each access pulse, and inputting each access pulse into the optical fiber circulator;

[0042] The fiber circulator sends each access pulse to each grating in the fiber grating array;

[0043] Correspondingly, the demodulation system is used to receive the reflected pulse reflected by each grating in the fiber grating array, demodulate each group of the reflected pulses to obtain a plurality of spectral data and corresponding reflection time differences, and send each of the spectral data and the corresponding reflection time differences to the processor, including:

[0044] Using the fiber circulator to receive the reflected pulses reflected by each grating in the fiber grating array, and inputting each group of the reflected pulses into the photodetector;

[0045] The photoelectric detector converts each group of the reflected pulses into individual electrical signals, and inputs each of the electrical signals into the data acquisition card;

[0046] The data acquisition card performs acquisition processing based on each of the electrical signals and the pulse signal output by the pulse generator to obtain a plurality of spectral data and corresponding reflection time differences, and sends each of the spectral data and the corresponding reflection time differences to the processor.

[0047] Preferably, the method further comprises:

[0048] Determining, using the processor, whether each of the spectral data is affected by crosstalk and shadow effects;

[0049] If so, for each spectral data affected by the crosstalk and the shadow effect, a layer-by-layer compensation algorithm is used to perform crosstalk suppression processing to obtain the processed spectral data.

[0050] Preferably, for each of the spectral data affected by the crosstalk and the shadow effect, crosstalk suppression processing is performed using a layer-by-layer compensation algorithm to obtain the processed spectral data, including:

[0051] Layering the gratings according to the central wavelengths corresponding to the gratings;

[0052] Calculate the first light intensity of the reflected pulses of each layer after the i-th layer reduced due to the access pulse being reflected by the i-th layer of the grating; i is a positive integer;

[0053] Calculate the second light intensity of the reflected pulse of the grating of the i-th layer after multiple first-order reflections and the reflected pulse of the i+1-th layer superimposed;

[0054] Accumulate each of the first light intensities and each of the second light intensities corresponding to the first i layers according to the time division multiplexing crosstalk generation principle to obtain an accumulation result;

[0055] For each spectral data affected by crosstalk in the i-th layer, crosstalk suppression is performed on the spectral data using the accumulated result to obtain the spectral data after crosstalk suppression;

[0056] The shadow effect compensation is calculated, and the spectrum data after the crosstalk suppression is compensated based on the shadow effect compensation to obtain the processed spectrum data.

[0057] Based on the above-mentioned embodiment of the present invention, a bank room temperature monitoring system and method based on a weak fiber grating array is provided. The system includes: a fiber grating array, a demodulation system and a processor; the fiber grating array is deployed on each wall surface in the bank room, and the fiber grating array is composed of a plurality of gratings; the demodulation system is used to generate a plurality of access pulses with different emission wavelengths; for each of the access pulses, it is sent to each grating in the fiber grating array; the reflected pulse reflected by each grating in the fiber grating array is received, and each group of the reflected pulses is demodulated to obtain a plurality of spectral data and corresponding reflection time difference; each of the spectral data and the corresponding reflection time difference is sent to the processor; the fiber grating array is used to output multiple groups of reflection pulses to the demodulation system; each group of reflection pulses is obtained by the corresponding grating reflecting the access pulses of different emission wavelengths; the processor is used to perform Gaussian fitting for each of the spectral data to obtain the reflection wavelength, and determine the grating corresponding to the spectral data based on the reflection time difference corresponding to each of the spectral data; monitor the change of the reflection wavelength of the spectral data corresponding to each grating to obtain the temperature change of the bank room. In this solution, optical fiber is used as a sensor, which has very stable properties, eliminates the influence of other factors on temperature monitoring except temperature, and has high accuracy; optical signal is used as the signal transmission medium, and the optical signal propagates quickly, so that the optical fiber sensor has a fast response speed; TDM and WDM technologies are used at the same time, which can ensure that the sensor monitoring accuracy is accurate to the centimeter level while ensuring the low cost of system construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0059] Figure 1 A structural diagram of a bank computer room temperature monitoring system based on a weak fiber grating array disclosed in an embodiment of the present invention;

[0060] Figure 2 A schematic diagram of a single-wall fiber grating array deployment method disclosed in an embodiment of the present invention;

[0061] Figure 3 The present invention discloses a flow chart of a method for monitoring temperature in a bank computer room based on a weak fiber grating array. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0064] First, the technical terms appearing in this application are explained as follows:

[0065] Weak fiber Bragg grating (wFBG): refers to a fiber Bragg grating with ultra-low reflectivity. A fiber Bragg grating is a grating with periodic spatial phase distribution formed in the fiber core by laser processing and other methods. Its essence is to form equidistant narrowband filters or reflectors in the fiber core. By using its reflection characteristics and the characteristics that its central wavelength changes with temperature, a quasi-distributed fiber Bragg grating sensing system can be constructed.

[0066] Quasi-distributed fiber optic sensing system (i.e. fiber grating array): multiple wFBGs can be multiplexed on one fiber to construct a quasi-distributed fiber grating sensing system, which has the advantages of high-speed response, high resolution, high sensitivity, and easy wavelength demodulation. However, multi-point measurement does not mean that any point on the fiber to be measured is a sensing point, but the measurement points are discretely distributed on the entire sensing fiber to achieve the purpose of distributed measurement, so it can only be called a quasi-distributed system.

[0067] Time Division Multiplexing (TDM): Time division multiplexing means using time as a reference for signal segmentation in a signal system. A signal system built using time division multiplexing technology divides the time for information transmission in the entire channel into several equally spaced time slices when processing signals. A quasi-distributed fiber grating sensing system built based on time division multiplexing technology distinguishes the optical signals returned by different wFBGs based on the time difference between the optical signals reflected by different wFBGs and returning to the signal receiver.

[0068] Wavelength Division Multiplexing (WDM): Wavelength division multiplexing is to couple multiple different wavelengths of carrier optical signals together at the transmitting end and transmit them through optical fiber, and then separate and demodulate the light of each wavelength at the receiving end to obtain the information carried by the different wavelength carriers. The quasi-distributed fiber grating sensing system built based on wavelength division multiplexing technology distinguishes the optical signals returned by different wFBGs according to the different center wavelengths of the spectrum returned by different wFBGs after scanning by the scanning laser.

[0069] Layer-by-layer compensation algorithm: The layer-by-layer compensation algorithm is based on the principle of crosstalk generated by time-division multiplexing of light grating arrays and related calculation methods. It uses layer-by-layer compensation to eliminate the influence of multiple reflected light and shadow effects corresponding to the previous grating on the subsequent grating reflected light layer by layer, thereby achieving the goal of improving the accuracy and stability of the measurement results of the quasi-distributed fiber Bragg grating wavelength demodulation system.

[0070] As can be seen from the background technology, the current monitoring system for bank computer room temperature monitoring is usually built with traditional electrical sensors. Due to the limitations of the working principle and manufacturing materials of traditional electrical sensors, they have shortcomings such as easy corrosion and loss, and weak resistance to external interference. At the same time, in order to achieve high-accuracy monitoring, a large number of sensors need to be deployed on the six sides of the computer room, which will lead to a surge in the cost of building the monitoring system. If the density of sensor deployment is reduced in order to save costs, it will lead to problems such as insufficient system monitoring accuracy and untimely response.

[0071] Therefore, the embodiment of the present invention discloses a bank room temperature monitoring system and method based on a weak fiber grating array. In this solution, optical fiber is used as a sensor, which has strong resistance to external interference and high accuracy. In addition, TDM and WDM technologies are used to maintain the accuracy of monitoring while ensuring low costs.

[0072] like Figure 1 FIG. 1 is a structural diagram of a bank room temperature monitoring system based on a weak fiber grating array according to an embodiment of the present invention. The system includes: a fiber grating array, a demodulation system and a processor.

[0073] Among them, the fiber grating array is deployed on the surface of each wall in the bank's computer room, and the fiber grating array is composed of multiple gratings.

[0074] The fiber grating array is used to output multiple groups of reflected pulses to the demodulation system; each group of reflected pulses is obtained by corresponding gratings reflecting access pulses of different output wavelengths.

[0075] like Figure 2 FIG. 1 is a schematic diagram of a single-wall fiber grating array deployment method disclosed in an embodiment of the present invention.

[0076] To ensure measurement accuracy, the distance between adjacent gratings in the deployed fiber grating array is about 50 cm. Figure 2 The length of the fiber turning point is exactly the distance between two adjacent gratings. Deploying the fiber grating array in this way can ensure that there is at least one fiber sensor in every 0.25 square meters (each grating is a fiber sensor), which greatly ensures the measurement accuracy.

[0077] Preferably, to achieve three-dimensional precise measurement, the fiber grating array needs to be evenly deployed on every wall of the bank's computer room, including the ceiling and floor of the computer room.

[0078] The demodulation system is called a quasi-distributed wavelength demodulation system, which is mainly used to demodulate the optical signal reflected by the fiber grating array.

[0079] Specifically, the demodulation system is used to generate multiple access pulses with different output wavelengths; for each access pulse, it is sent to each grating in the fiber grating array; it receives the reflected pulse reflected by each grating in the fiber grating array, and demodulates each group of reflected pulses to obtain multiple spectral data and corresponding reflection time differences; and each spectral data and corresponding reflection time difference is sent to the processor.

[0080] In the embodiment of the present invention, both the access pulse and the reflected pulse are optical signals.

[0081] Furthermore, the demodulation system includes: a scanning laser, an SOA module, an EDFA module, an optical fiber circulator, a photoelectric detector, a data acquisition card and a pulse generator.

[0082] The operating principle of the demodulation system is as follows: the optical signal is emitted from the scanning laser, modulated into pulse light by SOA (semiconductor optical amplifier), amplified by EDFA (erbium-doped fiber amplifier), and then enters the fiber grating array to be tested through the fiber circulator. The optical signal reflected by each grating is then converted into an electrical signal by the photodetector and finally collected by the data acquisition card.

[0083] The specific implementation process of the demodulation system is as follows:

[0084] The scanning laser is used to generate multiple optical signals with different output wavelengths and output them to the SOA module.

[0085] The SOA module is used to modulate each optical signal using the pulse signal output by the pulse generator to obtain each access pulse to be amplified, and input each access pulse to be amplified into the EDFA module.

[0086] The EDFA module amplifies each access pulse to be amplified to obtain each access pulse, and inputs each access pulse into the optical fiber circulator.

[0087] The fiber circulator is used for sending each access pulse to each grating in the fiber grating array; receiving the reflected pulse reflected by each grating in the fiber grating array, and inputting each group of reflected pulses into the photodetector.

[0088] The photoelectric detector is used to convert each group of reflected pulses into individual electrical signals and input each electrical signal into a data acquisition card.

[0089] The data acquisition card is used to collect and process the pulse signals output by the pulse generator based on the electrical signals to obtain a plurality of spectral data and corresponding reflection time differences; and send the spectral data and the corresponding reflection time differences to the processor.

[0090] It should be noted that the existing demodulation system is deployed in a time-division multiplexing manner to monitor scenes that are prone to structural deformation, such as bridges and elevator shafts. If the system is deployed in a time-division multiplexing mode, its measurement resolution is often 3-5 meters, which is not accurate enough due to the influence of signal acquisition frequency and optical signal propagation speed. At the same time, when the fiber grating array is too long, that is, when there are too many fiber grating sensors deployed on a single optical fiber in a time-division multiplexing manner, its time-division multiplexing crosstalk will be greatly increased, which will have a certain impact on the measurement accuracy of the back-end fiber grating sensor. In an embodiment of the present invention, the demodulation system is constructed in combination with the principles of time-division multiplexing and wavelength-division multiplexing to solve the above problems.

[0091] Specifically, the demodulation system adopts the time division multiplexing principle to distinguish the reflected pulses of different gratings according to the reflection time difference collected by the data acquisition card. However, it is limited by the acquisition frequency of the data acquisition card. In order to ensure the independence and integrity of the reflected pulses of each grating, the intervals between adjacent gratings cannot be too close.

[0092] Therefore, in order to improve the distribution density of gratings in the fiber Bragg grating array, the demodulation system also introduces wavelength division multiplexing technology. Assuming that the wavelength division multiplexing uses output wavelengths of 1546nm, 1548nm, 1550nm, 1552nm, and 1554nm, it is necessary to set the scanning range of the scanning laser to 1544nm to 1556nm. If needed, the step value of the laser scanning can be set to 0.008nm. Then, in order to obtain the complete spectral data of 5 adjacent gratings, it is necessary to emit 1500 lasers with different output wavelengths for scanning, and then distinguish the collected reflected pulses according to the reflection time difference, so as to obtain the complete spectral data of each grating.

[0093] Among them, the scanned wavelength range is from 1544nm to 1556nm; the scanned wavelength range: 1556nm-1544nm=12nm; when each wavelength step is 0.008nm, the number of scanned wavelengths: 12nm÷0.008nm=1500; therefore, within this range (1544nm to 1556nm), if each step is 0.008nm, there will be a total of 1500 wavelength points.

[0094] After obtaining the complete spectrum data of each grating, based on the principle that the central wavelength of the grating (fixed value at room temperature) changes linearly with the external temperature, the processor can realize distributed measurement of the room temperature, as follows:

[0095] The processor is used to perform Gaussian fitting on each spectral data to obtain the reflection wavelength, determine the grating corresponding to the spectral data based on the reflection time difference corresponding to each spectral data; monitor the change of the reflection wavelength of the spectral data corresponding to each grating to obtain the temperature change of the bank room.

[0096] It should be noted that because each grating has a fixed central wavelength, the central wavelength at room temperature is known, and then when the temperature changes, the central wavelength will shift, that is, there will be an offset value between the reflected wavelength and the central wavelength at room temperature. This solution calculates the temperature change based on this offset value. The central wavelength of the grating becomes smaller when the temperature drops and becomes larger when the temperature rises. This change value is linearly related to the temperature. Gaussian fitting is to determine the reflected wavelength after the offset.

[0097] In one embodiment, the system also includes: a display connected to the processor; accordingly, the processor is also used to: generate temperature change curves for various locations in the bank machine room based on the temperature changes in the bank machine room, and output the temperature change curves for each location to the display; the display is used to display the temperature change curves for each location.

[0098] Through the display, the temperature changes at various locations in the bank's computer room can be visualized, realizing distributed temperature monitoring.

[0099] Since bank computer rooms are generally large, a large number of fiber optic sensors need to be deployed to achieve high-precision measurements of the entire room. This will cause the reflected pulse of the end grating to be distorted by multiple reflections and shadow effects of the previous reflected pulse of the grating with the same central wavelength, thus affecting the accuracy of the measurement results.

[0100] In one embodiment, in order to ensure the accuracy of the measurement result, the processor is further configured to:

[0101] Determine whether each spectral data is affected by crosstalk and shadow effect; if so, use a layer-by-layer compensation algorithm to perform crosstalk suppression processing on each spectral data affected by crosstalk and shadow effect to obtain processed spectral data.

[0102] It should be noted that whether each spectral data is affected by crosstalk and shadow effects is mainly determined based on the number of gratings in the fiber grating array deployed in the bank's computer room and historical experience.

[0103] In the embodiment of the present invention, a layer-by-layer compensation algorithm is proposed to suppress crosstalk with reference to the idea of ​​the layer-stripping algorithm. When time division multiplexing and wavelength division multiplexing are used at the same time, if the layer-by-layer compensation method is used to suppress crosstalk, the gratings must first be grouped according to the central wavelength of the grating (i.e., a fixed central wavelength known at room temperature), and layer-by-layer compensation is performed according to the dimensions distinguished by the central wavelength. The main idea of ​​the algorithm is:

[0104] The fiber grating array is divided into discrete layers. Starting from the initial conditions, the structural parameters of the first layer are first obtained, and then the second layer is analyzed based on the transmission characteristics of the light field of this layer. When analyzing the second layer, the first layer has no effect on the parameter acquisition of all subsequent layers of the fiber grating array. In this way, the first layer can be peeled off, and the second layer can be regarded as the first layer. The above process is repeated until the last layer of the grating, thereby achieving the layer-by-layer acquisition of the structural parameters of each layer in the entire grating, and finally achieving the reconstruction of the entire fiber grating array spectrum.

[0105] Here, the structural parameter refers to the reflectivity of the grating.

[0106] Furthermore, the processor for performing crosstalk suppression processing on each spectral data affected by the crosstalk and shadow effect by using a layer-by-layer compensation algorithm to obtain processed spectral data is specifically used for:

[0107] The gratings are layered according to the central wavelengths corresponding to the gratings; the first light intensity of the reflected pulses of the layers after the i-th layer is calculated, which is caused by the reflection of the access pulse by the i-th layer grating, resulting in the reduction of the reflected pulses of the layers after the i-th layer; i is a positive integer; the second light intensity of the reflected pulse of the i-th layer grating is calculated after the reflected pulse is superimposed with the reflected pulse of the i+1-th layer after first-order multiple reflections; the first light intensities and the second light intensities corresponding to the first i layers are accumulated according to the time-division multiplexing crosstalk generation principle to obtain the accumulated result; for each spectral data affected by crosstalk in the i-th layer, the spectral data is crosstalk suppressed using the accumulated result to obtain the spectral data after crosstalk suppression; the shadow effect compensation is calculated, and the spectral data after crosstalk suppression is compensated based on the shadow effect compensation to obtain the processed spectral data.

[0108] The specific calculation process is as follows:

[0109] When only the influence of crosstalk caused by multiple reflections on the demodulation result is considered, the reflection spectrum will be affected by crosstalk only when the grating position is the third or later. Therefore, assuming that the light intensity reflected from the i-th grating is Re i (λ), assuming that all grating characteristic parameters in the fiber grating array are the same (i.e., using identical weak gratings as fiber sensors), the intensity of the reflected pulse of each layer of grating after compensation can be obtained as:

[0110]

[0111] Where R is the reflectivity of the grating corresponding to each fiber optic sensor, and I0 is the intensity of the incident light initially incident on the grating (i.e., the light intensity of the access pulse).

[0112] However, it is not possible to guarantee that the reflectivity of each grating in the fiber grating array is consistent, so if it is directly calculated as consistent, it will lead to large errors. According to the idea of ​​the layer stripping algorithm, the spectrum data of the reflected pulse of each layer of grating in the upstream layer can be used to calculate the spectrum data of the reflected pulse of the next layer of grating layer by layer, thereby achieving more accurate elimination of multiple reflection crosstalk. Through this method, the reflected light intensity of each layer of grating after suppressing crosstalk can be obtained as follows:

[0113]

[0114] Here, R i (λ) is the light intensity in the spectral data after crosstalk suppression.

[0115] In order to restore the original reflection spectrum of the grating as much as possible, it is also necessary to compensate for the weakening of the light intensity caused by the shadow effect. When considering multiple reflection crosstalk and shadow effects at the same time, the reflected light intensity of the fiber grating at the i-th layer can be obtained as follows:

[0116]

[0117] Among them, R i and R j is the reflectivity of the i-th and j-th grating layers, R j (λ) is the reflected light intensity of the j-th grating.

[0118] Here R i (λ) is the light intensity in the spectral data after compensation for the shadow effect.

[0119] The pseudo code for crosstalk suppression and shadow effect compensation using the layer-by-layer compensation algorithm is as follows:

[0120]

[0121] Based on the above-mentioned embodiment of the present invention, a bank computer room temperature monitoring system based on a weak fiber Bragg grating array is disclosed. It does not require complex lines and a large number of electrical sensors. It is simple to build and low-cost. At the same time, it does not need to introduce additional circuit systems in the bank computer room. Compared with the use of traditional electrical sensors for distributed deployment, it reduces the risk of additional circuits in the computer room. Fiber Bragg gratings are stable and reliable after deployment due to their stable physical properties and corrosion resistance. They are not easy to damage and are easy to maintain. At the same time, the system uses optical signals as detection signals, is not easily affected by external electromagnetic interference, and has accurate measurement results. In scenarios with a large number of electrical equipment such as computer rooms, the stability of its monitoring results is more guaranteed. The crosstalk problem caused by fiber Bragg grating time division multiplexing has always been an important factor affecting the measurement performance of large-scale quasi-distributed fiber Bragg grating sensing systems. The present invention proposes a crosstalk suppression method based on a layer-by-layer compensation algorithm, which greatly improves the measurement accuracy of the back-end grating of the computer room temperature monitoring system built on the principle of optical fiber wavelength demodulation.

[0122] like Figure 3 As shown, it is a flow chart of a bank computer room temperature monitoring method based on a weak fiber grating array disclosed in an embodiment of the present invention, which is applied to any bank computer room temperature monitoring system based on a weak fiber grating array disclosed in the above-mentioned embodiments of the present invention.

[0123] It should be noted that, for the explanation of the method, reference may be made to the bank computer room temperature monitoring system based on weak fiber grating array disclosed in the above-mentioned embodiment of the present invention.

[0124] The method comprises the following steps:

[0125] Step S101: using a demodulation system to generate a plurality of access pulses with different output wavelengths, and sending each access pulse to each grating in a fiber grating array.

[0126] Step S102: using a demodulation system to receive reflected pulses reflected by each grating in the fiber grating array, demodulating each group of reflected pulses to obtain a plurality of spectral data and corresponding reflection time differences, and sending each spectral data and corresponding reflection time difference to a processor.

[0127] Each group of reflected pulses is obtained by reflecting the access pulses of different emission wavelengths from the corresponding grating.

[0128] In step S102, the reflection time difference refers to the time difference between the reflected pulses reflected from different fiber gratings and reaching the receiver (photoelectric sensor).

[0129] In one embodiment, a processor is used to determine whether each spectral data is affected by crosstalk and shadow effects; if so, a layer-by-layer compensation algorithm is used to perform crosstalk suppression processing on each spectral data affected by crosstalk and shadow effects to obtain processed spectral data.

[0130] In the specific implementation process, each grating is layered according to the central wavelength corresponding to each grating; the first light intensity of the reflected pulse of each layer after the i-th layer is reduced due to the reflection of the access pulse by the i-th layer grating is calculated; i is a positive integer; the second light intensity of the reflected pulse of the i-th layer grating after the first-order multiple reflections and the superposition of the reflected pulse of the i+1-th layer is calculated; the first light intensities and the second light intensities corresponding to the first i layers are accumulated according to the time division multiplexing crosstalk generation principle to obtain the accumulated result; for each spectral data affected by crosstalk in the i-th layer, the spectral data is crosstalk suppressed using the accumulated result to obtain the spectral data after crosstalk suppression; the shadow effect compensation is calculated, and the spectral data after crosstalk suppression is compensated based on the shadow effect compensation to obtain the processed spectral data.

[0131] Step S103: using a processor to perform Gaussian fitting on each spectral data to obtain a reflection wavelength.

[0132] In step S103, the spectrum data of the fiber grating usually presents one or more sharp peaks, and the shapes of these peaks are usually close to Gaussian distribution. Therefore, a Gaussian function can be used to fit these peaks to extract the Bragg wavelength (i.e., reflection wavelength) of each fiber grating.

[0133] Step S104: using the processor and the reflection time difference corresponding to each spectral data, determine the grating corresponding to the spectral data.

[0134] In step S104, by measuring the reflection time difference, the reflection pulses reflected by different fiber gratings can be distinguished.

[0135] It should be noted that because the distance from the grating to the optical fiber incident port is fixed, after the access pulse is incident, the distance of the grating from the incident port can be located based on the propagation speed of light in the optical fiber and the time it takes for the reflected pulse to reach the photoelectric sensor, and thus each grating can be distinguished.

[0136] Step S105: Using a processor to monitor the change in the reflected wavelength of the spectral data corresponding to each grating, the temperature change of the bank's computer room is obtained.

[0137] In step S105, since the gratings are distributed at different positions, the temperature change at each position of the bank's computer room can be obtained by monitoring the change of the reflected wavelength of the gratings at different positions.

[0138] In one embodiment, the demodulation system includes: a scanning laser, an SOA module, an EDFA module, an optical fiber circulator, a photodetector, a data acquisition card, and a pulse generator.

[0139] Accordingly, a demodulation system is used to generate a plurality of access pulses with different emission wavelengths, and each access pulse is sent to each grating in the fiber grating array, including:

[0140] A scanning laser is used to generate multiple optical signals with different output wavelengths and output them to the SOA module. The SOA module uses the pulse signal output by the pulse generator to modulate each optical signal to obtain each access pulse to be amplified; each access pulse to be amplified is input into the EDFA module for amplification processing to obtain each access pulse, and each access pulse is input into the fiber circulator; the fiber circulator sends each access pulse to a grating in the fiber grating array.

[0141] Accordingly, a demodulation system is used to receive the reflected pulse reflected by each grating in the fiber grating array, demodulate each group of reflected pulses to obtain a plurality of spectral data and corresponding reflection time differences, and send each spectral data and corresponding reflection time difference to a processor, including:

[0142] A fiber circulator is used to receive reflected pulses reflected by each grating in the fiber grating array, and each group of reflected pulses is input into a photodetector; the photodetector converts each group of reflected pulses into individual electrical signals, and each electrical signal is input into a data acquisition card; the data acquisition card performs collection and processing based on each electrical signal and the pulse signal output by the pulse generator to obtain multiple spectral data and corresponding reflection time differences, and each spectral data and corresponding reflection time difference is sent to a processor.

[0143] Based on the above-mentioned embodiment of the present invention, a bank computer room temperature monitoring method based on a weak fiber Bragg grating array is disclosed. It does not require complex lines and a large number of electrical sensors. It is simple to build and low-cost. At the same time, it does not need to introduce additional circuit systems in the bank computer room. Compared with the use of traditional electrical sensors for distributed deployment, it reduces the risk of additional circuits in the computer room. Fiber Bragg gratings are stable and reliable after deployment due to their stable physical properties and corrosion resistance. They are not easy to damage and are easy to maintain. At the same time, the system uses optical signals as detection signals, is not easily affected by external electromagnetic interference, and has accurate measurement results. In scenarios with a large number of electrical equipment such as computer rooms, the stability of its monitoring results is more guaranteed. The crosstalk problem caused by fiber Bragg grating time division multiplexing has always been an important factor affecting the measurement performance of large-scale quasi-distributed fiber Bragg grating sensing systems. The present invention proposes a crosstalk suppression method based on a layer-by-layer compensation algorithm, which greatly improves the measurement accuracy of the back-end grating of the computer room temperature monitoring system built on the principle of optical fiber wavelength demodulation.

[0144] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0145] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0146] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bank room temperature monitoring system based on weak fiber grating array, characterized in that: The system includes: a fiber grating array, a demodulation system and a processor; the fiber grating array is deployed on the surface of each wall in the bank's computer room, and the fiber grating array is composed of multiple gratings; The demodulation system is used to generate a plurality of access pulses with different emission wavelengths; for each of the access pulses, send them to each grating in the fiber grating array; receive the reflected pulse reflected by each of the gratings in the fiber grating array, and demodulate each group of the reflected pulses to obtain a plurality of spectral data and corresponding reflection time differences; and send each of the spectral data and the corresponding reflection time differences to the processor; The fiber grating array is used to output multiple groups of reflected pulses to the demodulation system; each group of reflected pulses is obtained by the corresponding grating reflecting the access pulses of different emission wavelengths; The processor is used to perform Gaussian fitting on each spectral data to obtain the reflection wavelength, and determine the grating corresponding to the spectral data based on the reflection time difference corresponding to each spectral data; monitor the change of the reflection wavelength of the spectral data corresponding to each grating to obtain the temperature change of the bank room.

2. The system according to claim 1, characterized in that The demodulation system includes: a scanning laser, an SOA module, an EDFA module, an optical fiber circulator, a photoelectric detector, a data acquisition card and a pulse generator; The scanning laser is used to generate a plurality of optical signals with different emission wavelengths and output them to the SOA module; The SOA module is used to modulate each of the optical signals using the pulse signal output by the pulse generator to obtain each access pulse to be amplified, and input each access pulse to be amplified into the EDFA module; The EDFA module amplifies each access pulse to be amplified to obtain each access pulse, and inputs each access pulse into the optical fiber circulator; The fiber circulator is used to send each access pulse to each grating in the fiber grating array; receive the reflected pulse reflected by each grating in the fiber grating array, and input each group of the reflected pulses into the photodetector; The photoelectric detector is used to convert each group of the reflected pulses into individual electrical signals, and input each of the electrical signals into the data acquisition card; The data acquisition card is used to perform acquisition and processing based on each of the electrical signals and the pulse signal output by the pulse generator to obtain a plurality of spectral data and corresponding reflection time differences; and send each of the spectral data and the corresponding reflection time difference to the processor.

3. The system according to claim 1, characterized in that The processor is further configured to: Determine whether each of the spectral data is affected by crosstalk and shadow effects; If so, for each spectral data affected by the crosstalk and the shadow effect, a layer-by-layer compensation algorithm is used to perform crosstalk suppression processing to obtain the processed spectral data.

4. The system according to claim 3, characterized in that For each of the spectral data affected by the crosstalk and the shadow effect, a crosstalk suppression process is performed using a layer-by-layer compensation algorithm to obtain the processed spectral data, specifically for: Layering the gratings according to the central wavelengths corresponding to the gratings; Calculate the first light intensity of the reflected pulse of each layer after the i-th layer, which is reduced due to the reflection of the access pulse by the i-th layer of the grating; i is a positive integer; Calculate the second light intensity of the reflected pulse of the grating of the i-th layer after multiple first-order reflections and the reflected pulse of the i+1-th layer superimposed; Accumulate each of the first light intensities and each of the second light intensities corresponding to the first i layers according to the time division multiplexing crosstalk generation principle to obtain an accumulation result; For each spectral data affected by crosstalk in the i-th layer, crosstalk suppression is performed on the spectral data using the accumulated result to obtain the spectral data after crosstalk suppression; The shadow effect compensation is calculated, and the spectrum data after the crosstalk suppression is compensated based on the shadow effect compensation to obtain the processed spectrum data.

5. The system according to claim 1, characterized in that The processor is further configured to: Based on the temperature change of the bank computer room, a temperature change curve of each position in the bank computer room is generated.

6. The system according to claim 5, characterized in that The system further comprises: a display; The display is used to display the temperature change curve at each position.

7. A method for monitoring the temperature of a bank computer room based on a weak fiber grating array, characterized in that: The method applied to the bank computer room temperature monitoring system based on weak fiber grating array according to any one of claims 1 to 6 comprises: Generate a plurality of access pulses with different emission wavelengths by using a demodulation system, and send each of the access pulses to each grating in the fiber grating array; Using a demodulation system to receive the reflected pulses reflected by each grating in the fiber grating array, demodulating each group of the reflected pulses to obtain a plurality of spectrum data and corresponding reflection time differences, and sending each of the spectrum data and the corresponding reflection time differences to a processor; each group of the reflected pulses is obtained by the corresponding grating reflecting the access pulses of different emission wavelengths; Using the processor to perform Gaussian fitting on each of the spectral data to obtain a reflection wavelength; Determine the grating corresponding to the spectral data by using the processor and the reflection time difference corresponding to each spectral data; The processor is used to monitor the change of the reflection wavelength of the spectral data corresponding to each grating to obtain the temperature change of the bank room.

8. The method according to claim 7, characterized in that The demodulation system includes: a scanning laser, an SOA module, an EDFA module, an optical fiber circulator, a photoelectric detector, a data acquisition card and a pulse generator; Accordingly, the demodulation system is used to generate a plurality of access pulses with different emission wavelengths, and each access pulse is sent to each grating in the fiber grating array, including: The scanning laser is used to generate a plurality of optical signals with different emission wavelengths and output them to the SOA module. The SOA module uses the pulse signal output by the pulse generator to modulate each of the optical signals to obtain each access pulse to be amplified. Inputting each access pulse to be amplified into the EDFA module for amplification processing to obtain each access pulse, and inputting each access pulse into the optical fiber circulator; The fiber circulator sends each access pulse to each grating in the fiber grating array; Correspondingly, the demodulation system is used to receive the reflected pulse reflected by each grating in the fiber grating array, demodulate each group of the reflected pulses to obtain a plurality of spectral data and corresponding reflection time differences, and send each of the spectral data and the corresponding reflection time differences to the processor, including: Using the fiber circulator to receive the reflected pulses reflected by each grating in the fiber grating array, and inputting each group of the reflected pulses into the photodetector; The photoelectric detector converts each group of the reflected pulses into individual electrical signals, and inputs each of the electrical signals into the data acquisition card; The data acquisition card performs acquisition processing based on each of the electrical signals and the pulse signal output by the pulse generator to obtain a plurality of spectral data and corresponding reflection time differences, and sends each of the spectral data and the corresponding reflection time differences to the processor.

9. The method according to claim 7, characterized in that: The method further comprises: Determining, using the processor, whether each of the spectral data is affected by crosstalk and shadow effects; If so, for each spectral data affected by the crosstalk and the shadow effect, a layer-by-layer compensation algorithm is used to perform crosstalk suppression processing to obtain the processed spectral data.

10. The method according to claim 9, characterized in that The step of performing crosstalk suppression processing on each of the spectral data affected by the crosstalk and the shadow effect using a layer-by-layer compensation algorithm to obtain the processed spectral data includes: Layering the gratings according to the central wavelengths corresponding to the gratings; Calculate the first light intensity of the reflected pulses of each layer after the i-th layer reduced due to the access pulse being reflected by the i-th layer of the grating; i is a positive integer; Calculate the second light intensity of the reflected pulse of the grating of the i-th layer after multiple first-order reflections and the reflected pulse of the i+1-th layer superimposed; Accumulate each of the first light intensities and each of the second light intensities corresponding to the first i layers according to the time division multiplexing crosstalk generation principle to obtain an accumulation result; For each spectral data affected by crosstalk in the i-th layer, crosstalk suppression is performed on the spectral data using the accumulated result to obtain the spectral data after crosstalk suppression; The shadow effect compensation is calculated, and the spectrum data after the crosstalk suppression is compensated based on the shadow effect compensation to obtain the processed spectrum data.

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