A method and apparatus for predicting time division crosstalk of a fiber grating array

Abstract

The application relates to the technical field of optical fiber sensing, in particular to a prediction method and device for time division crosstalk of a fiber grating array. The prediction method comprises the following steps: simulating a main pulse after laser input into the fiber grating array; calculating the number of crosstalk pulses and the corresponding grating sequence number when each crosstalk pulse is reflected according to the time division channel number of the fiber grating array; simulating total crosstalk pulses according to the number of crosstalk pulses and the corresponding reflected grating sequence number when each crosstalk pulse is reflected; calculating total interference pulses according to the simulation results of the main pulse and the total crosstalk pulses, extracting interference signals from the total interference pulses and demodulating the interference signals. The application can comprehensively predict and evaluate the crosstalk of the fiber array by considering the size and phase information of the main pulse and the crosstalk pulse, thereby more accurately predicting the crosstalk of the fiber grating array and more detailedly displaying the channel interference pulses, interference signals and demodulation results under the influence of crosstalk.

Description

Technical Field

[0001] This application relates to the field of fiber optic sensing technology, specifically to a method and device for predicting time-division crosstalk in a fiber Bragg grating array. Background Technology

[0002] Fabry-Perot (FP) fiber Bragg grating (FBG) acoustic signal sensing systems based on matched interference have advantages such as simple structure, easy large-scale multiplexing, high sensitivity, and large dynamic range, and are therefore widely used in underwater acoustic sensing. While FBG arrays are ideal devices for underwater acoustic sensing, the simultaneous transmission and reflection of light by the FBG causes multiple reflections of the optical signal within the FP-type FBG array, generating crosstalk between array channels and degrading the array system's sensing performance. Generally, crosstalk between channels in time-division multiplexed arrays has the greatest impact on performance because the FBGs in a time-division multiplexed array have the same center wavelength. Therefore, accurate prediction of the crosstalk magnitude in time-division multiplexed FBG arrays is crucial for array design.

[0003] In related technologies, the analysis of crosstalk principles in fiber Bragg grating (FP-Cavity) hydrophones mainly involves calculating the amplitudes of the main pulse and crosstalk pulses based on the reflectivity R and transmittance (1-R) ​​of the fiber Bragg grating. However, existing technologies do not adequately consider the impact of interference between the main pulse and crosstalk pulses on the results, ignoring phase information and only using the worst-case interference signal amplitude to assess the crosstalk magnitude, leading to errors in the assessment and results. Therefore, accurately predicting the crosstalk situation in each channel of different fiber Bragg grating arrays is a pressing technical problem to be solved in optimizing fiber Bragg grating array design. Summary of the Invention

[0004] In related technologies, the analysis and prediction of time-division crosstalk for fiber Bragg grating arrays only uses the amplitude of the interference signal under the worst case to evaluate the crosstalk magnitude, which leads to errors in the evaluation and results.

[0005] In a first aspect, embodiments of this application provide a method for predicting time-division crosstalk in a fiber Bragg grating array, the prediction method comprising: The simulation is performed on the main pulse after the laser is input into the fiber Bragg grating array. The main pulse is the reflected pulse generated by the optical pulse entering the fiber Bragg grating array and only undergoing one reflection of the fiber Bragg grating, which is then transmitted to the first fiber Bragg grating and transmitted to the output array. The number of crosstalk pulses and the grating sequence number corresponding to each crosstalk pulse when it is reflected are calculated based on the number of time-division channels in the fiber grating array. The total crosstalk pulses are simulated based on the number of crosstalk pulses and the number of the reflection grating corresponding to each crosstalk pulse when it is reflected. The total interference pulse is calculated based on the simulation results of the main pulse and the total crosstalk pulse, and the interference signal is extracted from the total interference pulse and demodulated.

[0006] In conjunction with the first aspect, in one embodiment, calculating the number of crosstalk pulses and the grating sequence number corresponding to the reflection of each crosstalk pulse based on the time-division channel number of the fiber grating array includes: The number of reflections of the crosstalk pulse of the corresponding order in the fiber grating array is obtained based on the predicted crosstalk pulse order. The number of crosstalk pulses is calculated based on the number of time-division channels and the number of reflections of the fiber grating array, and the grating corresponding to each crosstalk pulse when it is reflected is obtained.

[0007] In conjunction with the first aspect, in one embodiment, simulating the total crosstalk pulses based on the number of crosstalk pulses and the corresponding grating number when each crosstalk pulse is reflected includes: The reflection process of the crosstalk pulse is simulated and calculated based on the grating number corresponding to each crosstalk pulse when it is reflected to obtain the reflection pulse results; Based on the reflected pulse results, the process of each crosstalk pulse being transmitted to the first fiber grating and then transmitted is simulated and calculated to obtain the corresponding crosstalk pulse signal. The total crosstalk pulse signal is obtained by summing all the crosstalk pulse signals.

[0008] In conjunction with the first aspect, in one embodiment, the step of simulating and calculating the reflection process of the crosstalk pulses based on the reflection grating number corresponding to each crosstalk pulse being reflected to obtain the reflection pulse result includes: The reflection order in each crosstalk pulse is obtained by determining the reflection grating number corresponding to each crosstalk pulse when it is reflected. The reflection process between gratings in a crosstalk pulse is simulated and calculated according to the reflection sequence.

[0009] In conjunction with the first aspect, in one embodiment, the simulation calculation of the reflection process between gratings in the crosstalk pulse according to the reflection sequence includes: The process of light pulse being transmitted from the first grating to the first ordinal grating in the reflection grating sequence is simulated and calculated to obtain the result of the first reflection pulse. The simulation calculations for all reflection pulse results are completed sequentially based on the first reflection pulse result and the reflection grating sequence.

[0010] In conjunction with the first aspect, in one embodiment, the simulation calculation of the process of the light pulse being transmitted from the first grating to the first ordinal grating in the reflection grating sequence to obtain the result of the first reflected pulse includes: According to the formula:

[0011]

[0012] Obtain the result of the first reflected pulse In the formula, r is the reflection coefficient. Where is the digital sampling rate, L is the fiber length between two adjacent gratings, c is the speed of light in a vacuum, and n is the effective refractive index of the fiber. For sound signals, This is the transmitted light pulse for the first grating.

[0013] In conjunction with the first aspect, in one embodiment, calculating the total interference pulse based on the main pulse and the total crosstalk pulse includes: According to the formula:

[0014] Obtain the total interference pulse In the formula, is the total crosstalk pulse signal, pulsesignalzt is the main pulse signal corresponding to the (Z+1)th fiber grating, pulsesignal0r is the main pulse corresponding to the first fiber grating, and a is the time-division channel number of the fiber grating array.

[0015] In conjunction with the first aspect, in one embodiment, the step of extracting the interference signal from the total interference pulse and demodulating the interference signal includes: According to the formula:

[0016] Acquire the interference signal for each time-division channel In the formula, TDM represents time-division channel. Where is the digital sampling rate, L is the fiber length between two adjacent gratings, c is the speed of light in a vacuum, and n is the effective refractive index of the fiber. Where is the pulse sampling rate, and N is the number of sampling points.

[0017] In conjunction with the first aspect, in one embodiment, simulating the main pulse after the laser is input into the fiber Bragg grating array includes: The simulation was performed based on preset simulation parameters to simulate the process of continuous laser output from the laser being input into the fiber grating array via an optical modulator and interferometer. The result was calculated that the reflected pulse generated by each fiber grating after receiving the first optical pulse was transmitted to the first fiber grating and then transmitted to the output array.

[0018] Secondly, embodiments of this application provide a device for predicting time-division crosstalk (TDC) of a fiber Bragg grating array, characterized in that the prediction device includes a processor, a memory, and a prediction program stored in the memory and executable by the processor, wherein when the prediction program is executed by the processor, it implements the steps of the method for predicting TDC of a fiber Bragg grating array as described in any of the preceding claims.

[0019] The beneficial effects of the technical solutions provided in this application include: This application, by considering the magnitude and phase information of the main pulse and crosstalk pulse, can comprehensively predict and evaluate the crosstalk situation of fiber arrays, thereby more accurately and comprehensively predicting the crosstalk situation of fiber Bragg grating arrays, and more detailedly showing the interference pulses, interference signals, and demodulation results of each channel under the influence of crosstalk, further guiding the array design of fiber Bragg gratings. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating an embodiment of the method for predicting time-division crosstalk in a fiber Bragg grating array according to this application. Figure 2 This is a schematic diagram of the laser output from the laser to the fiber grating array in one embodiment of this application; Figure 3 This is a schematic diagram of the interferometer in one embodiment of this application; Figure 4 This is a distance map of each crosstalk pulse transmission in one embodiment of this application; Figure 5 This is a diagram showing the total interference pulse calculation results in one embodiment of this application; Figure 6 This is a diagram showing the signal demodulation result of the first time division in one embodiment of this application; Figure 7 This is a diagram showing the signal demodulation result at the second time division in one embodiment of this application; Figure 8 This is a schematic diagram of a system using heterodyne modulation in one embodiment of this application; Figure 9 This is a schematic diagram of the hardware structure of the fiber grating array time-division crosstalk prediction device involved in the embodiments of this application. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0022] In related technologies, the analysis and prediction of time-division crosstalk for fiber Bragg grating arrays only uses the amplitude of the interference signal under the worst case to evaluate the crosstalk magnitude, which leads to errors in the evaluation and results.

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0024] In a first aspect, embodiments of this application provide a method for predicting time-division crosstalk in a fiber Bragg grating array, the prediction method comprising: Step S1: Simulate the main pulse after the laser is input into the fiber grating array. The main pulse is the reflected pulse generated by the optical pulse entering the fiber grating array and only undergoing reflection once by the fiber grating, and is transmitted to the first fiber grating and transmitted to the output array.

[0025] In one optional embodiment of this application, the process of the laser output to the fiber grating array is as follows: Figure 2 As shown, the process of continuous laser output from the laser being input into the fiber grating array via an optical modulator and interferometer is simulated according to preset simulation parameters. The results of the reflected pulse generated by each fiber grating after receiving the first optical pulse are calculated and transmitted to the first fiber grating and then through the output array.

[0026] The simulation process for the main pulse in this embodiment includes: Step S1a: Set simulation parameters.

[0027] Specifically, taking PGC modulation as an example, the simulation parameters that need to be set in this implementation scheme include: the reflectivity R of the fiber grating; the transmittance T = 1 - R; and the reflection coefficient. Transmission coefficient Interferometer arm length difference and fiber grating spacing (fiber length between two adjacent fiber gratings) L; characteristic frequency corresponding to the modulation method. Sound signal frequency Digital sampling rate Pulse sampling rate (pulse modulation period) Pulse width .

[0028] In some alternative implementations, if it is as follows Figure 8 The same applies to heterodyne modulation. Step S1a: Simulate the process from the laser to the acousto-optic modulator.

[0029] It should be noted that this process involves the continuous laser output from the laser being modulated into periodic pulsed light by an acousto-optic modulator.

[0030] First pulse light The expression is:

[0031] In the formula, Where t is the pulse period and t is the transmission coefficient. This represents the pulse width.

[0032] Step S1b: Simulate the process of pulsed light from the acousto-optic modulator to the interferometer.

[0033] It should be noted that the specific structure of the interferometer is as follows: Figure 3 As shown, in this simulation process, the modulated optical pulse output by the acousto-optic modulator is split into two optical pulses by a 2×2 coupler. These pulses pass through the reference arm and the signal arm, respectively, and are reflected by a Faraday rotator mirror before being transmitted back. The reference arm and the signal arm have different lengths and are both wound on a PZT. The difference in arm lengths causes the two optical pulses to have different transmission times. The two arms can modulate different signals. In this example, the carrier wave is modulated on the signal arm, and the reference acoustic signal can be selectively modulated on the reference arm. Finally, the pulses are reversed and combined by the 2×2 coupler into a dual optical pulse consisting of two optical pulses with a time delay.

[0034] Furthermore, two second light pulses , Represented as:

[0035] In the formula, This is the first pulse optical signal.

[0036] The optical pulse passing through the reference arm is modulated by the reference acoustic signal and represented as:

[0037]

[0038] In the formula, For reference acoustic signal, Using the reference acoustic signal frequency, the optical pulse passing through the sensing arm is modulated by a carrier wave as follows:

[0039] In the formula, The time delay caused by the difference in arm length during the round-trip transmission of light, c is the speed of light in a vacuum, and n is the effective refractive index of the optical fiber. After passing through the coupler, the two pulses are combined into one, which is the third pulse output by the interferometer. :

[0040] It should be noted that, as Figure 2The function of the circulator is to ensure the transmission sequence of light. The circulator allows the light output from the interferometer to be injected into the fiber Bragg grating array, while the light reflected back from the fiber Bragg grating enters the data acquisition unit. This application Figure 2 In this embodiment, the fiber Bragg grating array is an 8-time-division multiplexed array, consisting of 9 fiber Bragg gratings, with each pair of adjacent fiber Bragg gratings forming a sensing element.

[0041] Step S1c: Simulate the main pulse signal reflected after the pulse output by the interferometer is injected into the fiber grating.

[0042] Specifically, this application provides a specific embodiment of an 8-time-division multiplexing array, wherein step S1c includes: Step A: The first fiber grating will simultaneously reflect and transmit light pulses.

[0043] The reflected light of the first fiber grating and transmitted light pulse Represented as:

[0044] It should be noted that the first fiber grating mentioned above refers to the first fiber grating injected after an optical pulse is injected into the fiber grating array.

[0045] Step B, the delay and acoustic signal modulation of the transmitted light after passing through a section of optical fiber, can be represented as follows:

[0046] in, The pulse transmitted from the first fiber Bragg grating to the second fiber Bragg grating undergoes reflection and transmission upon encountering the second fiber Bragg grating, which can be represented as follows:

[0047] Step C, the reflected light from the second fiber grating will again undergo a delay and acoustic signal modulation after passing through a section of optical fiber, which can be represented as:

[0048] In the formula, This refers to the pulse that travels from the second fiber grating to the first fiber grating, and then, upon encountering the first fiber grating again, undergoes both reflection and transmission. These are represented as follows:

[0049] Step D: The transmitted light from the second fiber grating will repeat the above-described delay, acoustic signal modulation, and transmission / reflection process for the next fiber grating. This process can be repeated to calculate the result of the reflected pulse from each fiber grating being transmitted to the first fiber grating and then through the output array. , , , , , , , , That is, the main pulse reflected by the fiber grating.

[0050] Step S2: Calculate the number of crosstalk pulses and the grating sequence number corresponding to each crosstalk pulse when it is reflected, based on the number of time-division channels of the fiber grating array.

[0051] The above step S2 specifically includes: Step S2a: Obtain the number of reflections of the crosstalk pulse of the corresponding order in the fiber grating array based on the predicted crosstalk pulse order.

[0052] Specifically, if the target signal to be predicted is a first-order crosstalk pulse, then the first-order crosstalk pulse will be reflected three times in a fiber optic grating array.

[0053] Step S2b: Calculate the number of crosstalk pulses based on the number of time-division channels and the number of reflections of the fiber grating array, and obtain the grating corresponding to each crosstalk pulse when it is reflected.

[0054] In some alternative embodiments, taking a fiber Bragg grating array with 8 time-division channels as an example, there are 9 fiber Bragg gratings. The first reflection of the optical pulse will occur at any of the 2nd to 9th gratings, assuming the grating where the first reflection occurs is the i-th grating, i=2:1:9; the second reflection will occur at one of the 1st to (i-1th)th gratings, assuming the grating where the second reflection occurs is the j-th grating, j=1:1:i-1; the third reflection will occur at one of the (j+1th)th to 9th gratings, assuming the grating where the third reflection occurs is the k-th grating, k=j+1:1:9.

[0055] Understandably, knowing the time-minute fraction of the array allows us to calculate the number of crosstalk pulses and the corresponding grating number (i, j, k) for each crosstalk pulse. (See attached...) Figure 2 The 8-time-division grating array shown can be simulated to have a total of 204 crosstalk pulses and their corresponding 204 sets of grating numbers: i, j, k.

[0056] Furthermore, the transmission distance of each crosstalk pulse is shown in the attached figure. Figure 4 As shown, the red line represents the maximum transmission distance of the main pulse, and the yellow line represents the minimum transmission distance of the next cycle. Crosstalk pulses with a transmission distance below the red line affect the signal of the current cycle. Crosstalk between the red and yellow lines has no effect on the signal, while crosstalk pulses above the yellow line affect the signal of the next cycle. The 8-time-division array used in this example will not have crosstalk between cycles, but arrays with more time divisions will have this problem.

[0057] Step S3: Simulate the total crosstalk pulses based on the number of crosstalk pulses and the corresponding grating number when each crosstalk pulse is reflected.

[0058] The above step S3 specifically includes: Step S3a: Perform simulation calculations on the reflection process of crosstalk pulses based on the grating number corresponding to each crosstalk pulse when it is reflected to obtain the reflection pulse results.

[0059] Specifically, crosstalk pulses can be simulated based on the grating sequence number corresponding to the multiple reflections of each crosstalk pulse.

[0060] In some specific embodiments, step S3a includes: Step A: Obtain the reflection order of each crosstalk pulse based on the reflection grating number corresponding to each crosstalk pulse being reflected.

[0061] Specifically, taking the specific embodiment listed in step S2 as an example: the grating corresponding to the three reflections of a crosstalk pulse, such as the grating numbers i, j, k corresponding to the first crosstalk pulse being 2, 1, 2 respectively.

[0062] Step B: Simulate and calculate the reflection process between gratings in the crosstalk pulse according to the reflection sequence.

[0063] Specifically, the process of a light pulse being transmitted from the first grating to the first ordinal grating in the reflection grating sequence and then being reflected is simulated to obtain the result of the first reflected pulse: first, the process of the light pulse being transmitted from the first grating to the second grating is simulated, and the first reflected pulse after being transmitted to the second grating is calculated. Represented as:

[0064]

[0065] In the formula, The transmitted light pulse is the first grating pulse. r is the reflection coefficient. Where is the digital sampling rate, L is the fiber length between two adjacent gratings, c is the speed of light in a vacuum, and n is the effective refractive index of the fiber. It is an acoustic signal.

[0066] Based on the results of the first reflection pulse and the ordinal number of the reflection grating, perform simulation calculations for all reflection pulse results sequentially: The reflected pulse, transmitted back to the first grating, will be reflected again to form a second reflected pulse, which is represented as:

[0067]

[0068] Furthermore, the third reflected pulse, formed by the second reflected pulse transmitted through the optical fiber to the second grating and then reflected again, is represented as:

[0069]

[0070] Step S3b: Based on the reflected pulse results, simulate and calculate the process of each crosstalk pulse being transmitted to the first fiber grating and then transmitted to obtain the corresponding crosstalk pulse signal. Specifically, taking the above embodiment as an example, the transmission that occurs when the third pulse is transmitted to the first grating is this crosstalk pulse, which is represented as:

[0071]

[0072] Step S3c: Add all the crosstalk pulse signals together to obtain the total crosstalk pulse signal.

[0073] Total crosstalk pulse signal Represented as:

[0074] In the formula, m is the total number of crosstalk pulses corresponding to one grating calculated in step S2.

[0075] Step S4: Calculate the total interference pulse based on the simulation results of the main pulse and the total crosstalk pulse. Specifically, according to the formula:

[0076] Obtain the total interference pulse In the formula, For total crosstalk pulse signal, This is the main pulse signal corresponding to the (Z+1)th fiber grating. This is the main pulse corresponding to the first fiber Bragg grating, where 'a' is the time-division multiplexing channel number of the fiber Bragg grating array. Further pulse calculation results are attached. Figure 5 As shown, yellow represents the power of the total interference pulse, while red and blue represent the amplitude and power of the crosstalk pulse, respectively.

[0077] Step S5: Extract the interference signal from the total interference pulse and demodulate the interference signal.

[0078] Assuming the number of gratings is Then the array has Each time-division channel is represented by TDM, 0 <TDM< The signal for each time-division channel is:

[0079] Acquire the interference signal for each time-division channel In the formula, TDM represents time-division channel. Where is the digital sampling rate, L is the fiber length between two adjacent gratings, c is the speed of light in a vacuum, and n is the effective refractive index of the fiber. Where is the pulse sampling rate, and N is the number of sampling points. Based on the modulation method used in this example, the signal can be demodulated using the PGC demodulation algorithm.

[0080] In some specific embodiments, with a reflectivity of 0.1, an arm length difference of 20m, an acoustic signal amplitude of 1rad, and a frequency of 400Hz, the demodulation results of the signals in the first and second time segments after the signal is added only in the first time segment are shown in the appendix. Figure 6 , 7 As shown.

[0081] Secondly, embodiments of this application provide a device for predicting time-division crosstalk (TDC) of a fiber Bragg grating array. The device for predicting TDC of a fiber Bragg grating array can be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0082] Reference Figure 9 , Figure 9 This is a schematic diagram of the hardware structure of the time-division crosstalk prediction device for a fiber Bragg grating array involved in the embodiments of this application. In the embodiments of this application, the time-division crosstalk prediction device for a fiber Bragg grating array may include a processor, a memory, a communication interface, and a communication bus.

[0083] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0084] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces used for interconnecting internal devices within the fiber Bragg grating array time-division crosstalk (TDCC) prediction device, as well as interfaces used for interconnecting the TDCC prediction device with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0085] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0086] The processor can be a general-purpose processor, which can call the time-division crosstalk prediction program for fiber Bragg grating arrays stored in the memory and execute the time-division crosstalk prediction method for fiber Bragg grating arrays provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the time-division crosstalk prediction program for fiber Bragg grating arrays is called can refer to the various embodiments of the time-division crosstalk prediction method for fiber Bragg grating arrays in this application, and will not be repeated here.

[0087] Those skilled in the art will understand that Figure 9 The hardware structure shown does not constitute a limitation of this application and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0088] Fourthly, embodiments of this application also provide a computer-readable storage medium.

[0089] The present application stores a program for predicting time-division crosstalk (TDC) of a fiber Bragg grating array on a computer-readable storage medium. When the program is executed by a processor, it implements the steps of the TDC prediction method for a fiber Bragg grating array as described above.

[0090] The method implemented when the time division crosstalk prediction program of the fiber Bragg grating array is executed can be referred to in various embodiments of the time division crosstalk prediction method of the fiber Bragg grating array of this application, and will not be repeated here.

[0091] In summary, by considering the magnitude and phase information of the main pulse and crosstalk pulse, this application can comprehensively predict and evaluate the crosstalk situation of fiber arrays, thereby more accurately and comprehensively predicting the crosstalk situation of fiber Bragg grating arrays, and more detailedly demonstrating the interference pulses, interference signals, and demodulation results of each channel under the influence of crosstalk, further guiding the array design of fiber Bragg gratings.

[0092] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0093] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0094] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0095] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0096] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0097] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0098] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for predicting time-division crosstalk in a fiber optic grating array, characterized in that, The prediction method includes: The simulation is performed on the main pulse after the laser is input into the fiber Bragg grating array. The main pulse is the result of the light pulse entering the fiber Bragg grating array, undergoing only one reflection of the fiber Bragg grating, being transmitted to the first fiber Bragg grating, and then being transmitted to the output array. The number of crosstalk pulses and the grating sequence number corresponding to each crosstalk pulse when it is reflected are calculated based on the number of time-division channels in the fiber grating array. The total crosstalk pulses are simulated based on the number of crosstalk pulses and the number of the reflection grating corresponding to each crosstalk pulse when it is reflected. The total interference pulse is calculated based on the simulation results of the main pulse and the total crosstalk pulse, and the interference signal is extracted from the total interference pulse and demodulated.

2. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 1, characterized in that, The calculation of the number of crosstalk pulses and the grating sequence number corresponding to the reflection of each crosstalk pulse based on the time-division channel number of the fiber grating array includes: The number of reflections of the crosstalk pulse of the corresponding order in the fiber grating array is obtained based on the predicted crosstalk pulse order. The number of crosstalk pulses is calculated based on the number of time-division channels and the number of reflections of the fiber grating array, and the grating corresponding to each crosstalk pulse when it is reflected is obtained.

3. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 1, characterized in that, The simulation of the total crosstalk pulses based on the number of crosstalk pulses and the corresponding grating number when each crosstalk pulse is reflected includes: The reflection process of the crosstalk pulse is simulated and calculated based on the grating number corresponding to each crosstalk pulse when it is reflected to obtain the reflection pulse results; Based on the reflected pulse results, the process of each crosstalk pulse being transmitted to the first fiber grating and then transmitted is simulated and calculated to obtain the corresponding crosstalk pulse signal. The total crosstalk pulse signal is obtained by summing all the crosstalk pulse signals.

4. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 3, characterized in that, The step of simulating and calculating the reflection process of crosstalk pulses based on the reflection grating ordinal number corresponding to each crosstalk pulse being reflected to obtain the reflection pulse results includes: The reflection order in each crosstalk pulse is obtained by determining the reflection grating number corresponding to each crosstalk pulse when it is reflected. The reflection process between gratings in a crosstalk pulse is simulated and calculated according to the reflection sequence.

5. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 4, characterized in that, The simulation calculation of the reflection process between gratings in the crosstalk pulse according to the reflection sequence includes: The process of light pulse being transmitted from the first grating to the first ordinal grating in the reflection grating sequence is simulated and calculated to obtain the result of the first reflection pulse. The simulation calculations for all reflection pulse results are completed sequentially based on the first reflection pulse result and the reflection grating sequence.

6. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 5, characterized in that, The simulation calculation of the process of the light pulse being transmitted from the first grating to the first ordinal grating in the reflection grating sequence to obtain the result of the first reflection pulse includes: According to the formula: Obtain the result of the first reflected pulse In the formula, r is the reflection coefficient. Where is the digital sampling rate, L is the fiber length between two adjacent gratings, c is the speed of light in a vacuum, and n is the effective refractive index of the fiber. For sound signals, This is the transmitted light pulse for the first grating.

7. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 1, characterized in that, The calculation of the total interference pulse based on the main pulse and the total crosstalk pulse includes: According to the formula: Obtain the total interference pulse In the formula, For total crosstalk pulse signal, This is the main pulse signal corresponding to the (Z+1)th fiber grating. It is the main pulse signal corresponding to the first fiber Bragg grating, and 'a' is the time-division channel number of the fiber Bragg grating array.

8. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 1, characterized in that, The step of extracting the interference signal from the total interference pulse and demodulating the interference signal includes: According to the formula: Acquire the interference signal for each time-division channel In the formula, TDM represents time-division channel. Where is the digital sampling rate, L is the fiber length between two adjacent gratings, c is the speed of light in a vacuum, and n is the effective refractive index of the fiber. Where is the pulse sampling rate, and N is the number of sampling points.

9. The method for predicting time-division crosstalk in a fiber optic grating array as described in claim 1, characterized in that, The simulation of the main pulse after the laser is input into the fiber grating array includes: The simulation was performed based on preset simulation parameters to simulate the process of continuous laser output from the laser being input into the fiber grating array via an optical modulator and interferometer. The result was calculated that the reflected pulse generated by each fiber grating after receiving the first optical pulse was transmitted to the first fiber grating and then transmitted to the output array.

10. A device for predicting time-division crosstalk in a fiber Bragg grating array, characterized in that, The prediction device includes a processor, a memory, and a prediction program stored in the memory and executable by the processor, wherein when the prediction program is executed by the processor, it implements the steps of the prediction method for time-division crosstalk of a fiber Bragg grating array as described in any one of claims 1 to 9.

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