CN119449177B - Methods, apparatus, equipment, and storage media for measuring the Kerr effect nonlinear coefficient of hollow-core optical fiber. - Google Patents
Methods, apparatus, equipment, and storage media for measuring the Kerr effect nonlinear coefficient of hollow-core optical fiber.Info
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- CN119449177B CN119449177B CN202411445334.XA CN202411445334A CN119449177B CN 119449177 B CN119449177 B CN 119449177B CN 202411445334 A CN202411445334 A CN 202411445334A CN 119449177 B CN119449177 B CN 119449177B
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Abstract
本申请公开了一种空芯光纤克尔效应非线性系数测量方法、装置、设备及存储介质，涉及光通信技术领域，该方法包括：接收发射端中待测空芯光纤传输的高阶调制信号，对高阶调制信号进行解调制，得到高阶解调信号；将高阶解调信号映射至星座图中，并确定高阶解调信号在星座图中的非线性相移；基于高阶解调信号在星座图中的非线性相移以及预构建的克尔效应非线性数学模型，确定待测空芯光纤的克尔效应非线性折射率系数；基于待测空芯光纤的克尔效应非线性折射率系数，优化待测空芯光纤的通信性能。通过上述方式，对解调制后信号星座图中的映射点进行分析，确定非线性相移，从而利用非线性数学模型与非线性相移准确计算出克尔效应非线性折射率系数。
This application discloses a method, apparatus, device, and storage medium for measuring the Kerr effect nonlinear coefficient of hollow-core optical fiber, relating to the field of optical communication technology. The method includes: receiving a high-order modulated signal transmitted in the hollow-core optical fiber under test at the transmitting end; demodulating the high-order modulated signal to obtain a high-order demodulated signal; mapping the high-order demodulated signal onto a constellation diagram and determining the nonlinear phase shift of the high-order demodulated signal in the constellation diagram; determining the Kerr effect nonlinear refractive index coefficient of the hollow-core optical fiber under test based on the nonlinear phase shift of the high-order demodulated signal in the constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model; and optimizing the communication performance of the hollow-core optical fiber under test based on the Kerr effect nonlinear refractive index coefficient. Through the above method, the mapping points in the constellation diagram of the demodulated signal are analyzed to determine the nonlinear phase shift, thereby accurately calculating the Kerr effect nonlinear refractive index coefficient using the nonlinear mathematical model and the nonlinear phase shift.
Description
Technical Field
The present application relates to the field of optical communications technologies, and in particular, to a method, an apparatus, a device, and a storage medium for measuring a kerr effect nonlinear coefficient of an air core optical fiber.
Background
With the rise of technologies and industries such as cloud computing, big data, artificial intelligence and the like, the demand for ultra-large capacity ultra-low time delay data transmission is rapidly increased. The hollow fiber has the outstanding advantages of low nonlinearity, large communication window, small loss and the like, can well solve the capacity and time delay limit problems of commercial quartz fiber in physical characteristics, and becomes a main technical means for constructing a next-generation large-bandwidth low-time delay optical communication system.
Nonlinear effects are the main factor that currently limits the capacity, distance rise of fiber optic communication systems, with the Kerr (Kerr) effect most severely affecting high-speed optical signals. Therefore, in order to take advantage of the performance of the fiber channel, it is necessary to perform channel modeling and characterization on the kerr effect nonlinearity of the fiber, so as to improve the system performance by establishing an adaptive code modulation equalization method. However, it is difficult to precisely measure the nonlinear refractive index coefficient of the hollow fiber by the currently adopted measurement method.
The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present invention and is not intended to represent an admission that the foregoing is prior art.
Disclosure of Invention
The application mainly aims to provide a method, a device, equipment and a storage medium for measuring the Kerr effect nonlinear coefficient of an air core optical fiber, and aims to solve the technical problem that the Kerr effect nonlinear refractive index of the air core optical fiber is difficult to measure accurately in the prior art.
In order to achieve the above purpose, the present application provides a method for measuring the kerr effect nonlinear coefficient of a hollow fiber, which comprises the following steps:
receiving a high-order modulation signal transmitted by a hollow fiber to be detected in a transmitting end, and demodulating the high-order modulation signal to obtain a high-order demodulation signal;
mapping the high-order demodulation signal into a constellation diagram, and determining nonlinear phase shift of the high-order demodulation signal in the constellation diagram;
Based on the nonlinear phase shift of the high-order demodulation signal in a constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model, determining the Kerr effect nonlinear refractive index of the hollow fiber to be detected;
and optimizing the communication performance of the hollow fiber to be tested based on the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested.
In one embodiment, a first correspondence between signal strength, effective fiber length, kerr effect nonlinear coefficient and nonlinear phase shift is obtained;
Determining a second corresponding relation among the slope of a fitting curve of the signal intensity and the nonlinear phase shift, the effective fiber length and the Kerr effect nonlinear coefficient based on the first corresponding relation;
Acquiring a third corresponding relation among the Kerr effect nonlinear refractive index coefficient, the effective mode field area, the wavelength of the signal light and the Kerr effect nonlinear coefficient;
based on the second correspondence, converting the third correspondence into a fourth correspondence between a fitted curve slope of signal intensity and nonlinear phase shift, an effective mode field area, a signal light wavelength, an effective fiber length, a kerr effect nonlinear coefficient, and a kerr effect nonlinear refractive index coefficient;
and constructing the Kerr effect nonlinear mathematical model based on the fourth corresponding relation.
In an embodiment, mapping the high-order demodulation signal into a constellation diagram, and determining a center position of a mapping point of the high-order demodulation signal in the constellation diagram;
Determining a rotation angle between a mapping point and an origin based on the center position of the mapping point of the high-order demodulation signal in a constellation diagram;
Based on the rotation angle, a nonlinear phase shift of the high order demodulation signal in a constellation is determined.
In an embodiment, the mapping points of the high-order demodulation signal in the constellation diagram are classified according to the signal intensity, and a plurality of mapping groups are determined, wherein the signal intensity of the mapping points in each mapping group is the same;
And determining an arithmetic average value of the rotation angles of the mapping groups based on the rotation angles of the mapping points in the mapping groups, and taking the arithmetic average value of the rotation angles of the mapping groups as the nonlinear phase shift of the mapping points in the mapping groups.
In an embodiment, the mapping points of the high-order demodulation signals in the constellation diagram are clustered, and the clustering center of the mapping points of the high-order demodulation signals in the constellation diagram is determined;
And determining the central position of the mapping point of the high-order demodulation signal in the constellation diagram based on the position of the clustering center of the mapping point of the high-order demodulation signal in the constellation diagram.
In one embodiment, the high-order modulated signal is obtained by modulating a high-order quadrature amplitude modulated signal on a plurality of orthogonal subcarriers, the high-order quadrature amplitude modulated signal being modulated using a coherent optical orthogonal frequency division multiplexing modulation scheme, the rate of the quadrature amplitude modulated signal being greater than the rate of the subcarriers.
In an embodiment, a total time period is determined based on the number of subcarriers and the time period of the subcarriers;
Determining the dispersion length of the hollow fiber to be measured based on the total time period and the group velocity dispersion parameter of the hollow fiber to be measured, wherein the lifting multiple between the dispersion length of the hollow fiber to be measured and the single carrier modulation dispersion length is the square number of the subcarriers;
And when the transmission distance of the high-order modulated signal is smaller than the dispersion length, executing the step of receiving the high-order modulated signal transmitted by the hollow fiber to be detected in the transmitting end, and demodulating the high-order modulated signal to obtain a high-order demodulated signal.
In addition, in order to achieve the above object, the present application also provides a hollow fiber kerr effect nonlinear coefficient measuring apparatus, which includes:
the demodulation module is used for receiving the high-order modulation signal transmitted by the hollow fiber to be detected in the transmitting end, and demodulating the high-order modulation signal to obtain a high-order demodulation signal;
a mapping module, configured to map the high-order demodulation signal into a constellation diagram, and determine a nonlinear phase shift of the high-order demodulation signal in the constellation diagram;
the characterization module is used for determining the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be detected based on the nonlinear phase shift of the high-order demodulation signal in the constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model;
and the optimization module is used for optimizing the communication performance of the hollow fiber to be tested based on the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested.
In addition, in order to achieve the aim, the application also provides a hollow fiber Kerr effect nonlinear coefficient measuring device, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the computer program is configured to realize the steps of the hollow fiber Kerr effect nonlinear coefficient measuring method.
In addition, in order to achieve the above objective, the present invention further provides a storage medium, which is a computer readable storage medium, and a computer program is stored on the storage medium, and the computer program when executed by a processor implements the steps of the above hollow fiber kerr effect nonlinear coefficient measurement method.
In addition, to achieve the above object, the present application also provides a computer program product, which includes a computer program, and the computer program when executed by a processor implements the steps of the hollow fiber kerr effect nonlinear coefficient measurement method as described above.
The application provides a method for measuring a Kerr effect nonlinear coefficient of an air core optical fiber, which comprises the steps of receiving a high-order modulation signal transmitted by the air core optical fiber to be measured in a transmitting end, demodulating the high-order modulation signal to obtain a high-order demodulation signal, mapping the high-order demodulation signal into a constellation diagram, determining the nonlinear phase shift of the high-order demodulation signal in the constellation diagram, determining the Kerr effect nonlinear refractive index coefficient of the air core optical fiber to be measured based on the nonlinear phase shift of the high-order demodulation signal in the constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model, and optimizing the communication performance of the air core optical fiber to be measured based on the Kerr effect nonlinear refractive index coefficient of the air core optical fiber to be measured. By means of the method, the received modulation signal is demodulated, the constellation diagram damaged by nonlinearity is recovered, the mapping points in the constellation diagram are analyzed, and the nonlinear phase shift is determined, so that the Kerr effect nonlinear refractive index is accurately calculated by means of fine characterization of a Kerr effect nonlinear mathematical model and the nonlinear phase shift, and an adaptive code modulation balance strategy can be established to improve communication performance, and the technical problem that the Kerr effect nonlinear refractive index of the hollow fiber is difficult to accurately measure is solved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to a person skilled in the art that other drawings can be obtained from these drawings without inventive effort.
FIG. 1 is a schematic flow chart of a method for measuring the Kerr effect nonlinear coefficient of an air core fiber according to an embodiment of the application;
Fig. 2 is a schematic diagram of a mapping relationship of a 64QAM modulation constellation in a method for measuring a kerr effect nonlinear coefficient of an air core optical fiber according to an embodiment of the present application;
FIG. 3 is a schematic diagram of nonlinear phase shift of a method for measuring Kerr effect nonlinear coefficient of hollow fiber according to an embodiment of the present application;
FIG. 4 is a schematic diagram showing the slope of a fitted curve of a method for measuring the Kerr effect nonlinear coefficient of an air core fiber according to an embodiment of the present application;
FIG. 5 is a schematic flow chart of a second embodiment of a Kerr-effect nonlinear coefficient measurement method for hollow-core optical fibers;
FIG. 6 is a schematic flow chart of a third embodiment of a method for measuring the Kerr effect nonlinear coefficient of an air core fiber according to the present application;
fig. 7 is a schematic diagram of the overall architecture of a method for measuring the kerr effect nonlinear coefficient of an air core fiber according to the third embodiment of the present application;
fig. 8 is a schematic diagram of a transmitting end DSP of a method for measuring a kerr effect nonlinear coefficient of an air core fiber according to a third embodiment of the present application;
Fig. 9 is a schematic diagram of a receiving end DSP of a method for measuring a kerr effect nonlinear coefficient of an air core fiber according to a third embodiment of the present application;
FIG. 10 is a schematic block diagram of a Kerr effect nonlinear coefficient measurement device of an embodiment of the application;
Fig. 11 is a schematic diagram of an apparatus structure of a hardware operating environment related to a method for measuring a kerr effect nonlinear coefficient of a hollow core fiber according to an embodiment of the present application.
The achievement of the objects, functional features and advantages of the present application will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the technical solution of the present application and are not intended to limit the present application.
For a better understanding of the technical solution of the present application, the following detailed description will be given with reference to the drawings and the specific embodiments.
The main solution of the embodiment of the application is that the high-order modulation signal transmitted by the hollow fiber to be tested in the transmitting end is received, the high-order modulation signal is demodulated to obtain the high-order demodulation signal, the high-order demodulation signal is mapped into a constellation diagram, the nonlinear phase shift of the high-order demodulation signal in the constellation diagram is determined, the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested is determined based on the nonlinear phase shift of the high-order demodulation signal in the constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model, and the communication performance of the hollow fiber to be tested is optimized based on the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested.
At present, the adopted measurement mode is difficult to accurately measure the Kerr effect nonlinear refractive index coefficient of the hollow fiber.
The application provides a solution, which is to demodulate a received modulation signal, recover a constellation diagram damaged by nonlinearity, analyze mapping points in the constellation diagram, determine nonlinear phase shift, thereby utilizing a Kerr effect nonlinear mathematical model to perform fine characterization on the nonlinear phase shift, accurately calculate a Kerr effect nonlinear refractive index, further establish an adaptive code modulation equalization strategy to improve communication performance, and solve the technical problem that the Kerr effect nonlinear refractive index of an air core optical fiber is difficult to accurately measure.
It should be noted that, the execution body of the embodiment may be a computing service device with functions of data processing, network communication and program running, such as a tablet computer, a personal computer, a mobile phone, or an electronic device, a hollow fiber kerr effect nonlinear coefficient measuring device, or the like, which can implement the above functions, and the embodiment is not limited in particular. The present embodiment and the following embodiments will be described below by taking a hollow fiber kerr effect nonlinear coefficient measurement apparatus as an example.
The embodiment of the application provides a hollow fiber Kerr effect nonlinear coefficient measurement method, and referring to FIG. 1, FIG. 1 is a flow chart of a first embodiment of the hollow fiber Kerr effect nonlinear coefficient measurement method.
In this embodiment, the method for measuring the kerr effect nonlinear coefficient of the hollow fiber includes steps S10 to S40:
step S10, receiving a high-order modulation signal transmitted by an air core optical fiber to be detected in a transmitting end, and demodulating the high-order modulation signal to obtain a high-order demodulation signal;
The hollow fiber to be measured is the hollow fiber with the Kerr effect nonlinear coefficient to be measured. The high-order modulation signal is a signal transmitted from the transmitting end to the receiving end through the hollow fiber to be measured, and is obtained by modulating a high-order quadrature amplitude modulation signal on a plurality of quadrature subcarriers, wherein the quadrature amplitude modulation signal is a high-order QAM (Quadrature Amplitude Modulation ) signal, that is, the high-order modulation signal is a modulated high-order QAM signal. In this embodiment, the high-order QAM signal is modulated by using a coherent optical orthogonal frequency division multiplexing modulation scheme, that is, CO-OFDM (Coherent Optical Orthogonal Frequency Division Multiplexing ) technology, where the high-order modulated signal may be considered as a high-order OFDM-QAM signal, and in other embodiments, intensity modulation may be used to directly detect OFDM (Direct Detection Optical Orthogonal Frequency Division Multiplexing, DDO-OFDM), which is not particularly limited.
It can be understood that, through CO-OFDM, a high-order QAM signal can be modulated on a plurality of orthogonal low-speed subcarriers, and the rate of the quadrature amplitude modulation signal is far greater than that of the subcarriers, so that a larger dispersion length is obtained, and further, long-distance measurement of the high-order OFDM-QAM signal is realized.
It should be understood that, after the receiving end receives the high-order modulated signal, the high-order modulated signal is demodulated, and the signal obtained after demodulation is the high-order demodulated signal, where the high-order demodulated signal usually has a certain nonlinear impairment, if the kerr effect nonlinear coefficient is directly calculated, it is difficult to ensure accuracy.
Step S20, mapping the high-order demodulation signal into a constellation diagram, and determining nonlinear phase shift of the high-order demodulation signal in the constellation diagram;
It should be noted that, in this embodiment, the high-order demodulation signal is mapped to a constellation, where the mapping points in the constellation generally include symbol information with different magnitudes and different phase combinations, for example, referring to fig. 2, for 64QAM, the different mapping points correspond to different positions in two-dimensional coordinates, which are expressed as coordinates ,A total of 64 map points. Under the influence of Kerr nonlinear effect, the mapping points in the constellation diagram are usually rotated, the rotation angles of the mapping points are nonlinear phase shifts of the mapping points, and referring to FIG. 3, the mapping points with different signal strengths experience nonlinear phase shifts with different degrees。
It can be appreciated that the present embodiment needs to determine the nonlinear phase shift of the higher-order demodulation signal in the constellation, and can find the center position in the constellation first, and determine the final nonlinear phase shift according to the rotation angle between the center position and the origin.
Step S30, determining the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be detected based on the nonlinear phase shift of the high-order demodulation signal in a constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model;
It should be noted that, the Kerr effect nonlinear mathematical model is a constellation mapping-Kerr nonlinear mathematical model constructed in this embodiment.
In one possible implementation, the step of constructing the kerr effect nonlinear mathematical model may include steps S301 to S303:
step S301, a first corresponding relation among signal intensity, effective optical fiber length, kerr effect nonlinear coefficient and nonlinear phase shift is obtained, and a second corresponding relation among fitting curve slope of the signal intensity and nonlinear phase shift, the effective optical fiber length and Kerr effect nonlinear coefficient is determined based on the first corresponding relation;
the first correspondence between the signal intensity, the effective fiber length, the kerr effect nonlinear coefficient and the nonlinear phase shift, that is, the calculation relation of the nonlinear phase shift, is described as follows:
In the formula, Representing the non-linear phase shift,The signal strength is indicated by the signal strength,The time is represented by the time period of the day,Representing the kerr effect non-linear coefficient,Indicating the effective fiber length. The calculated relationship for the effective fiber length is as follows:
In the formula, Indicating the length of the effective optical fiber,The loss factor is represented by the number of the coefficients of loss,Indicating the actual length of the hollow fiber to be measured.
Additionally, it should be noted that, referring to FIG. 4, the nonlinear phase shiftAnd signal strengthThe slope of the curve can be obtained by fitting, namely, the slope of the fitted curve. The second correspondence between the signal strength and the fitted curve slope of the nonlinear phase shift, the effective fiber length, and the kerr effect nonlinear coefficient, i.e., the calculated relationship of the fitted curve slope, is as follows:
In the formula, Represents the slope of the fitted curve,Representing the kerr effect non-linear coefficient,Indicating the effective fiber length.
Step S302, a third corresponding relation among a Kerr effect nonlinear refractive index coefficient, an effective mode field area, a signal light wavelength and the Kerr effect nonlinear coefficient is obtained, and the third corresponding relation is converted into a fourth corresponding relation among a fitting curve slope of signal intensity and nonlinear phase shift, an effective mode field area, a signal light wavelength, an effective optical fiber length, the Kerr effect nonlinear coefficient and the Kerr effect nonlinear refractive index coefficient based on the second corresponding relation;
the third correspondence relationship between the Kerr effect nonlinear refractive index, the effective mode field area, the signal light wavelength, and the Kerr effect nonlinear coefficient, i.e., the calculated relationship of the Kerr nonlinear coefficient, is as follows:
In the formula, Representing the kerr effect nonlinear index of refraction,Representing the effective mode field area of the hollow fiber to be measured,Represents the signal light wavelength of the high-order demodulation signal,Representing the kerr effect nonlinear coefficient. Thus, the following calculation relation can be obtained:
Further, according to By deduction, a fourth corresponding relation among the slope of the fitted curve of the signal intensity and the nonlinear phase shift, the effective mode field area, the signal light wavelength, the effective optical fiber length, the Kerr effect nonlinear coefficient and the Kerr effect nonlinear refractive index coefficient can be obtained, and is as follows:
In the formula, Representing the kerr effect nonlinear index of refraction,Representing the effective mode field area of the hollow fiber to be measured,Represents the signal light wavelength of the high-order demodulation signal,Represents the slope of the fitted curve,Indicating the effective fiber length.
And step S303, constructing the Kerr effect nonlinear mathematical model based on the fourth corresponding relation.
It can be understood that the kerr effect nonlinear mathematical model is constructed based on a fourth correspondence between the fitted curve slope of the signal intensity and nonlinear phase shift, the effective mode field area, the signal light wavelength, the effective fiber length, the kerr effect nonlinear coefficient, and the kerr effect nonlinear refractive index coefficient.
It should be understood that the nonlinear refractive index of the hollow fiber to be measured can be calculated by substituting the nonlinear phase shift of the high-order demodulation signal in the constellation diagram into the Kerr effect nonlinear mathematical model。
Furthermore, other desired parameters in the model, besides nonlinear phase shift, can be obtained by characterizing the hollow-core fiber to be measured, such as effective fiber length, effective mode field area. And the signal light wavelength of the high-order modulation signal can be regulated to carry out multiple measurements, and the average value of the multiple measurements is taken as the final Kerr effect nonlinear refractive index coefficient so as to reduce measurement errors.
And step S40, optimizing the communication performance of the hollow fiber to be tested based on the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested.
It should be noted that, after the characterization of the kerr effect nonlinear coefficient of the hollow fiber to be tested is completed, the communication performance can be improved by establishing an adaptive code modulation equalization strategy.
The embodiment provides a method for measuring a Kerr effect nonlinear coefficient of an air core optical fiber, which is used for receiving a high-order modulation signal transmitted by the air core optical fiber to be measured in a transmitting end, demodulating the high-order modulation signal to obtain a high-order demodulation signal, mapping the high-order demodulation signal into a constellation diagram, determining the nonlinear phase shift of the high-order demodulation signal in the constellation diagram, determining the Kerr effect nonlinear refractive index coefficient of the air core optical fiber to be measured based on the nonlinear phase shift of the high-order demodulation signal in the constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model, and optimizing the communication performance of the air core optical fiber to be measured based on the Kerr effect nonlinear refractive index coefficient of the air core optical fiber to be measured. Through the method, the received modulation signal is demodulated, the constellation diagram damaged by nonlinearity is recovered, the mapping points in the constellation diagram are analyzed, and the nonlinear phase shift is determined, so that the Kerr effect nonlinear refractive index is accurately calculated by utilizing the Kerr effect nonlinear mathematical model and the nonlinear phase shift to carry out fine characterization, and an adaptive code modulation equalization strategy can be established to improve the communication performance.
In the second embodiment of the present application, the same or similar content as in the first embodiment of the present application may be referred to the description above, and will not be repeated. On this basis, referring to fig. 5, step S20 may include steps S201 to S203:
step S201, mapping the high-order demodulation signal into a constellation diagram, and determining the center position of a mapping point of the high-order demodulation signal in the constellation diagram;
In a possible implementation manner, step S201 includes clustering mapping points of the higher-order demodulation signals in a constellation, determining a clustering center of the mapping points of the higher-order demodulation signals in the constellation, and determining a center position of the mapping points of the higher-order demodulation signals in the constellation based on a position of the clustering center of the mapping points of the higher-order demodulation signals in the constellation.
It can be understood that, in this embodiment, the clustering algorithm is used to analyze the mapping points in the constellation diagram, and determine the clustering center, so as to find the center position of the mapping points in the constellation diagram. The clustering algorithm may be a K-means clustering algorithm, or may be any other suitable clustering method, or may be a deep learning algorithm or a genetic algorithm, which is not limited in particular. In the embodiment, a K-means clustering algorithm is adopted, so that the complexity of the DSP is not increased.
Step S202, determining a rotation angle between a mapping point and an origin based on the center position of the mapping point in a constellation diagram of the high-order demodulation signal;
It should be noted that, according to the center position of the mapping point in the constellation, the rotation angle of the mapping point with respect to the origin may be obtained.
Step S203, determining a nonlinear phase shift of the high-order demodulation signal in the constellation diagram based on the rotation angle.
In a possible implementation manner, step S203 includes classifying mapping points of the high-order demodulation signal in a constellation diagram according to signal intensity, determining a plurality of mapping groups, wherein the signal intensity of the mapping points in each mapping group is the same, determining an arithmetic average value of rotation angles of the mapping groups based on rotation angles of the mapping points in the mapping groups, and taking the arithmetic average value of rotation angles of the mapping groups as a nonlinear phase shift of the mapping points in the mapping groups.
It should be noted that, in this embodiment, the mapping points are classified according to signal intensities, the mapping points with the same signal intensities are used as a group, and one group of mapping points is the mapping group, so that multiple groups of mapping groups can be obtained, where the signal intensities of the mapping points in the mapping groups are the same. The arithmetic average value of the rotation angles is taken as the nonlinear phase shift of the mapping group, so that the influence of sampling variation is reduced.
The embodiment provides a hollow fiber Kerr effect nonlinear coefficient measurement method, which comprises the steps of mapping a high-order demodulation signal into a constellation diagram, determining the central position of a mapping point of the high-order demodulation signal in the constellation diagram, determining the rotation angle between the mapping point and an origin based on the central position of the mapping point of the high-order demodulation signal in the constellation diagram, determining the nonlinear phase shift of the high-order demodulation signal in the constellation diagram based on the rotation angle, accurately determining the central position of the mapping point through clustering, and accurately calculating the nonlinear phase shift, so that the Kerr effect nonlinear refractive index can be accurately calculated by utilizing a Kerr effect nonlinear mathematical model to carry out fine characterization on the nonlinear phase shift, and further an adaptive code modulation equalization strategy can be established to improve communication performance.
In the third embodiment of the present application, the same or similar contents as those of the above-described embodiments can be referred to the above description, and the description thereof will not be repeated. On this basis, referring to fig. 6, step S10 may include steps S01 to S03:
step S01, determining a total time period based on the number of the subcarriers and the time period of the subcarriers;
it should be noted that, fiber dispersion is one of the non-negligible channel impairment phenomena in an optical communication system, its influence is related to the signal rate, and the dispersion length is calculated as follows:
In the formula, Representing the time period of the higher order modulated signal, the inverse of which corresponds to the baud rate of the higher order modulated signal,Indicating the group velocity dispersion parameter, the group velocity dispersion value of the hollow core fiber is about one sixth of that of the quartz fiber.
It will be appreciated that when the actual fiber transmission distance isWhen the signal transmission is not affected by chromatic dispersion, when the actual optical fiber transmission distance isWhen the signal transmission is greatly affected by dispersion, the Kerr nonlinear coefficient cannot be characterized by signal distortion (nonlinear phase shift).
Thus, the present embodiment modulates a high-order QAM signal onto multiple orthogonal low-speed subcarriers, assuming commonSub-carriers, for modulation asTime period for higher order modulated signals of individual subcarriers,The time period of each subcarrier is represented, so that the total time period, i.e., the total time period, can be calculated as the time period of the high-order modulation signal according to the number of subcarriers and the time period of the subcarriers.
Step S02, based on the total time period and the group velocity dispersion parameter of the hollow fiber to be measured, determining the dispersion length of the hollow fiber to be measured, wherein the lifting multiple between the dispersion length of the hollow fiber to be measured and the single carrier modulation dispersion length is the square number of the subcarriers;
It should be noted that, according to the total time period and the group velocity dispersion parameter of the hollow fiber to be measured, the dispersion length of the hollow fiber to be measured is calculated, and at this time, compared with the single carrier modulation dispersion length, the dispersion length of the hollow fiber to be measured in this embodiment can be increased The improvement factor is the square number of the subcarriers, so that the measurement length can be effectively improved.
And S03, executing the step of receiving the high-order modulated signal transmitted by the hollow fiber to be tested in the transmitting end and demodulating the high-order modulated signal to obtain a high-order demodulated signal when the transmission distance of the high-order modulated signal is smaller than the dispersion length.
It can be understood that when the transmission distance of the high-order modulated signal is smaller than the dispersion length, steps S10 to S40 are performed to characterize the kerr effect nonlinear coefficient of the hollow fiber to be measured. The embodiment can promote the measurement length to be single carrier modulationMultiple times.
Further, the transmitting end can add a Cyclic Prefix (CP) into the signal to prevent inter-symbol interference caused by channel dispersion.
The embodiment provides a hollow fiber Kerr effect nonlinear coefficient measurement method, which modulates a high-order QAM signal on a plurality of orthogonal low-speed subcarriers, so as to obtain a larger dispersion length and further realize long-distance measurement of the high-order OFDM-QAM signal.
For an example, in order to facilitate understanding of the implementation flow of the method for measuring the kerr effect nonlinear coefficient of the hollow fiber according to the third embodiment, please refer to fig. 7, fig. 7 provides a schematic diagram of the overall architecture of the method for measuring the kerr effect nonlinear coefficient of the hollow fiber, specifically:
The optical power of the incoming fiber is varied by adjusting the value of an adjustable optical attenuator (Variable Optical Attenuator, VOA) at the transmitting end to better excite nonlinear effects. The OFDM baseband signal is generated in digital signal Processing (DIGITAL SIGNAL Processing, DSP), referring to fig. 8, a serial bit stream input from a transmitting end is firstly converted into a multi-path parallel data stream through serial/parallel conversion, each path of data is subjected to symbol mapping according to QAM modulation, the mapped data is filled with zeros to construct a guard band, then inverse fourier transform (INVERSE FAST Fourier Transform, IFFT) is performed, cyclic prefix is added to a time-domain OFDM signal to prevent inter-symbol interference caused by channel dispersion, and after serial/parallel conversion, the serial bit stream is converted into an analog signal, i.e., a baseband OFDM signal through an arbitrary waveform generator (Arbitrary Waveform Generator, AWG). The transmitting end adopts a scheme of continuously tunable laser and IQ modulator, the electric signal to be transmitted is modulated to the light field, the modulated optical signal enters the hollow fiber transmission link to be tested after passing through the optical amplifier, the received optical signal is changed into an analog electric signal through the coherent receiver, and finally, the analog electric signal is sampled into a digital signal by the real-time oscilloscope and is further processed by the DSP. Referring to fig. 9, the processing flow of the received high-order modulated signal by the receiving end includes synchronization, phase noise compensation, serial-parallel conversion, CP removal, FFT, demodulation, QAM mapping, and the like, and according to the constellation mapping relationship after demodulation, the central position of each mapping point is represented, and finally the Kerr nonlinear refractive index coefficient of the hollow fiber to be detected is obtained by calculation, and meanwhile, the link and DSP parameters can be optimized according to the quality (such as signal-to-noise ratio and bit error rate) of the output signal, so as to obtain the optimal state.
It should be noted that the foregoing examples are only for understanding the present application, and do not constitute limitation of the method for measuring the kerr effect nonlinear coefficient of the hollow fiber of the present application, and it is within the scope of the present application to perform more simple transformation based on the technical idea.
The application also provides a device for measuring the nonlinear coefficient of the kerr effect of the hollow fiber, referring to fig. 10, the device for measuring the nonlinear coefficient of the kerr effect of the hollow fiber comprises:
The demodulation module 10 is configured to receive a high-order modulated signal transmitted by an air core optical fiber to be tested in the transmitting end, and demodulate the high-order modulated signal to obtain a high-order demodulated signal.
A mapping module 20, configured to map the higher order demodulation signal into a constellation diagram, and determine a nonlinear phase shift of the higher order demodulation signal in the constellation diagram.
The characterization module 30 is configured to determine a kerr effect nonlinear refractive index coefficient of the hollow fiber to be measured based on a nonlinear phase shift of the high-order demodulation signal in a constellation diagram and a pre-constructed kerr effect nonlinear mathematical model.
And the optimizing module 40 is used for optimizing the communication performance of the hollow fiber to be tested based on the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested.
In a possible embodiment, the characterization module 30 is further configured to obtain a first correspondence between the signal strength, the effective fiber length, the kerr effect nonlinear coefficient and the nonlinear phase shift;
Determining a second corresponding relation among the slope of a fitting curve of the signal intensity and the nonlinear phase shift, the effective fiber length and the Kerr effect nonlinear coefficient based on the first corresponding relation;
Acquiring a third corresponding relation among the Kerr effect nonlinear refractive index coefficient, the effective mode field area, the wavelength of the signal light and the Kerr effect nonlinear coefficient;
based on the second correspondence, converting the third correspondence into a fourth correspondence between a fitted curve slope of signal intensity and nonlinear phase shift, an effective mode field area, a signal light wavelength, an effective fiber length, a kerr effect nonlinear coefficient, and a kerr effect nonlinear refractive index coefficient;
and constructing the Kerr effect nonlinear mathematical model based on the fourth corresponding relation.
In a possible implementation manner, the mapping module 20 is further configured to map the higher-order demodulation signal into a constellation diagram, and determine a center position of a mapping point of the higher-order demodulation signal in the constellation diagram;
Determining a rotation angle between a mapping point and an origin based on the center position of the mapping point of the high-order demodulation signal in a constellation diagram;
Based on the rotation angle, a nonlinear phase shift of the high order demodulation signal in a constellation is determined.
In a possible implementation manner, the mapping module 20 is further configured to classify mapping points of the high-order demodulation signal in the constellation according to signal strength, and determine a plurality of mapping groups, where the signal strength of the mapping points in each mapping group is the same;
And determining an arithmetic average value of the rotation angles of the mapping groups based on the rotation angles of the mapping points in the mapping groups, and taking the arithmetic average value of the rotation angles of the mapping groups as the nonlinear phase shift of the mapping points in the mapping groups.
In a possible implementation manner, the mapping module 20 is further configured to cluster mapping points of the higher-order demodulation signal in a constellation map, and determine a cluster center of the mapping points of the higher-order demodulation signal in the constellation map;
And determining the central position of the mapping point of the high-order demodulation signal in the constellation diagram based on the position of the clustering center of the mapping point of the high-order demodulation signal in the constellation diagram.
In a possible embodiment, the high-order modulated signal is obtained by modulating a high-order quadrature amplitude modulated signal on a plurality of orthogonal subcarriers, the high-order quadrature amplitude modulated signal being modulated using a coherent optical orthogonal frequency division multiplexing modulation scheme, the rate of the quadrature amplitude modulated signal being greater than the rate of the subcarriers.
In a possible implementation, the demodulation module 10 is further configured to determine a total time period based on the number of subcarriers and the time period of the subcarriers;
Determining the dispersion length of the hollow fiber to be measured based on the total time period and the group velocity dispersion parameter of the hollow fiber to be measured, wherein the lifting multiple between the dispersion length of the hollow fiber to be measured and the single carrier modulation dispersion length is the square number of the subcarriers;
And when the transmission distance of the high-order modulated signal is smaller than the dispersion length, executing the step of receiving the high-order modulated signal transmitted by the hollow fiber to be detected in the transmitting end, and demodulating the high-order modulated signal to obtain a high-order demodulated signal.
The device for measuring the nonlinear coefficient of the hollow fiber Kerr effect provided by the application can solve the technical problem that the nonlinear refractive index coefficient of the hollow fiber Kerr effect is difficult to accurately measure by adopting the method for measuring the nonlinear coefficient of the hollow fiber Kerr effect in the embodiment. Compared with the prior art, the hollow fiber Kerr effect nonlinear coefficient measuring device has the advantages that the hollow fiber Kerr effect nonlinear coefficient measuring device has the same advantages as the hollow fiber Kerr effect nonlinear coefficient measuring method provided by the embodiment, and other technical features in the hollow fiber Kerr effect nonlinear coefficient measuring device are the same as the features disclosed by the method of the embodiment, and are not repeated herein.
The application provides a hollow fiber Kerr effect nonlinear coefficient measuring device, which comprises at least one processor and a memory in communication connection with the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the hollow fiber Kerr effect nonlinear coefficient measuring method in the first embodiment.
Referring now to FIG. 11, a schematic diagram of a hollow core fiber Kerr effect nonlinear coefficient measurement apparatus suitable for use in implementing embodiments of the present application is shown. The hollow fiber kerr effect nonlinear coefficient measuring apparatus in the embodiment of the present application may include, but is not limited to, mobile terminals such as mobile phones, notebook computers, digital broadcast receivers, PDAs (Personal DIGITAL ASSISTANT: personal digital assistants), PADs (Portable Application Description: tablet computers), PMPs (Portable MEDIA PLAYER: multimedia players), vehicle-mounted terminals (e.g., vehicle-mounted navigation terminals), and the like, and fixed terminals such as digital TVs, desktop computers, and the like. The hollow fiber kerr effect nonlinear coefficient measuring apparatus shown in fig. 11 is only one example and should not impose any limitation on the functions and the scope of use of the embodiments of the present application.
As shown in fig. 11, the hollow fiber kerr effect nonlinear coefficient measuring apparatus may include a processing device 1001 (e.g., a central processor, a graphic processor, etc.) which may perform various appropriate actions and processes according to a program stored in a Read Only Memory 1002 or a program loaded from a storage device 1003 into a random access Memory (RAM: random Access Memory) 1004. In the RAM1004, various programs and data required for the operation of the hollow fiber kerr effect nonlinear coefficient measuring apparatus are also stored. The processing device 1001, the ROM1002, and the RAM1004 are connected to each other by a bus 1005. An input/output (I/O) interface 1006 is also connected to the bus. In general, a system including an input device 1007 such as a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc., an output device 1008 including a Liquid crystal display (LCD: liquid CRYSTAL DISPLAY), a speaker, a vibrator, etc., a storage device 1003 including a magnetic tape, a hard disk, etc., and a communication device 1009 may be connected to the I/O interface 1006. The communication means 1009 may allow the hollow fiber kerr effect nonlinear coefficient measurement apparatus to communicate with other apparatuses wirelessly or by wire to exchange data. While a hollow core fiber kerr effect nonlinear coefficient measurement apparatus having various systems is shown, it should be understood that not all of the illustrated systems are required to be implemented or provided. More or fewer systems may alternatively be implemented or provided.
In particular, according to embodiments of the present disclosure, the processes described above with reference to flowcharts may be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising program code for performing the method shown in the flow chart. In such an embodiment, the computer program may be downloaded and installed from a network through a communication device, or installed from the storage device 1003, or installed from the ROM 1002. The above-described functions defined in the method of the disclosed embodiment of the application are performed when the computer program is executed by the processing device 1001.
The hollow fiber Kerr effect nonlinear coefficient measuring equipment provided by the application can solve the technical problem that the Kerr effect nonlinear refractive index of the hollow fiber is difficult to accurately measure by adopting the hollow fiber Kerr effect nonlinear coefficient measuring method in the embodiment. Compared with the prior art, the beneficial effects of the hollow fiber Kerr effect nonlinear coefficient measurement device provided by the application are the same as those of the hollow fiber Kerr effect nonlinear coefficient measurement method provided by the embodiment, and other technical features of the hollow fiber Kerr effect nonlinear coefficient measurement device are the same as those disclosed in the method of the previous embodiment, so that the description is omitted.
It is to be understood that portions of the present disclosure may be implemented in hardware, software, firmware, or a combination thereof. In the description of the above embodiments, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily appreciate variations or alternatives within the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.
The present application provides a computer readable storage medium having computer readable program instructions (i.e., a computer program) stored thereon for performing the hollow fiber kerr effect nonlinear coefficient measurement method in the above-described embodiments.
The computer readable storage medium provided by the present application may be, for example, a U disk, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, or device, or a combination of any of the foregoing. More specific examples of a computer-readable storage medium may include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access Memory (RAM: random Access Memory), a Read-Only Memory (ROM), an erasable programmable Read-Only Memory (EPROM: erasable Programmable Read Only Memory or flash Memory), an optical fiber, a portable compact disc Read-Only Memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In this embodiment, a computer-readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, or device. Program code embodied on a computer readable storage medium may be transmitted using any appropriate medium, including but not limited to electrical wiring, fiber optic cable, RF (Radio Frequency) and the like, or any suitable combination of the foregoing.
The computer readable storage medium may be included in the hollow fiber kerr effect nonlinear coefficient measuring apparatus or may exist alone without being assembled into the hollow fiber kerr effect nonlinear coefficient measuring apparatus.
The computer readable storage medium carries one or more programs, when the one or more programs are executed by the hollow fiber Kerr effect nonlinear coefficient measuring equipment, the hollow fiber Kerr effect nonlinear coefficient measuring equipment receives a high-order modulation signal transmitted by the hollow fiber to be measured in a transmitting end, demodulates the high-order modulation signal to obtain a high-order demodulation signal, maps the high-order demodulation signal into a constellation diagram, determines nonlinear phase shift of the high-order demodulation signal in the constellation diagram, determines the Kerr effect nonlinear refractive index of the hollow fiber to be measured based on the nonlinear phase shift of the high-order demodulation signal in the constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model, and optimizes communication performance of the hollow fiber to be measured based on the Kerr effect nonlinear refractive index of the hollow fiber to be measured.
Computer program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of remote computers, the remote computer may be connected to the user's computer through any kind of network, including a local area network (LAN: local Area Network) or a wide area network (WAN: wide Area Network), or may be connected to an external computer (for example, through the Internet using an Internet service provider).
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The modules involved in the embodiments of the present application may be implemented in software or in hardware. Wherein the name of the module does not constitute a limitation of the unit itself in some cases.
The readable storage medium provided by the application is a computer readable storage medium, and the computer readable storage medium is stored with computer readable program instructions (namely computer program) for executing the hollow fiber Kerr effect nonlinear coefficient measurement method, so that the technical problem that the hollow fiber Kerr effect nonlinear refractive index is difficult to accurately measure can be solved. Compared with the prior art, the beneficial effects of the computer readable storage medium provided by the application are the same as those of the hollow fiber Kerr effect nonlinear coefficient measuring method provided by the embodiment, and the detailed description is omitted.
The application also provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of the hollow fiber kerr effect nonlinear coefficient measurement method as described above.
The computer program product provided by the application can solve the technical problem that the Kerr effect nonlinear refractive index of the hollow fiber is difficult to accurately measure. Compared with the prior art, the beneficial effects of the computer program product provided by the application are the same as those of the hollow fiber Kerr effect nonlinear coefficient measuring method provided by the embodiment, and the detailed description is omitted.
The foregoing is only a part of embodiments of the present application, and is not intended to limit the scope of the present application, and all the equivalent structural changes made by the description and drawings of the present application or the direct/indirect application in other related technical fields are included in the scope of the present application.
Claims (7)
1. The method for measuring the Kerr effect nonlinear coefficient of the hollow fiber is characterized by comprising the following steps of:
receiving a high-order modulation signal transmitted by a hollow fiber to be detected in a transmitting end, and demodulating the high-order modulation signal to obtain a high-order demodulation signal;
The method comprises the steps of mapping a high-order demodulation signal into a constellation diagram, determining nonlinear phase shift of the high-order demodulation signal in the constellation diagram, clustering mapping points of the high-order demodulation signal in the constellation diagram, determining a clustering center of the mapping points of the high-order demodulation signal in the constellation diagram, determining a center position of the mapping points of the high-order demodulation signal in the constellation diagram based on the position of the clustering center of the mapping points of the high-order demodulation signal in the constellation diagram, determining a rotation angle between the mapping points and an origin based on the center position of the mapping points of the high-order demodulation signal in the constellation diagram, classifying the mapping points of the high-order demodulation signal in the constellation diagram according to signal intensity, determining a plurality of mapping groups, wherein the signal intensity of the mapping points in each mapping group is the same, determining a rotation angle arithmetic average value of the mapping groups based on the rotation angle arithmetic average value of the mapping points in the mapping groups, and taking the rotation angle arithmetic average value of the mapping groups as the nonlinear phase shift of the mapping points in the mapping groups;
Based on the nonlinear phase shift of the high-order demodulation signal in a constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model, determining the Kerr effect nonlinear refractive index of the hollow fiber to be detected;
and optimizing the communication performance of the hollow fiber to be tested based on the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested.
2. The method of claim 1, wherein the step of determining the kerr effect nonlinear refractive index of the hollow-core fiber under test based on the nonlinear phase shift of the higher-order demodulation signal in the constellation and a pre-constructed kerr effect nonlinear mathematical model further comprises, prior to:
Acquiring a first corresponding relation among signal intensity, effective optical fiber length, kerr effect nonlinear coefficient and nonlinear phase shift;
Determining a second corresponding relation among a fitting curve slope of the signal intensity and the nonlinear phase shift, the effective fiber length and the Kerr effect nonlinear coefficient based on the first corresponding relation;
Acquiring a third corresponding relation among the Kerr effect nonlinear refractive index coefficient, the effective mode field area, the wavelength of the signal light and the Kerr effect nonlinear coefficient;
based on the second correspondence, converting the third correspondence into a fourth correspondence between a fitted curve slope of signal intensity and nonlinear phase shift, an effective mode field area, a signal light wavelength, an effective fiber length, a kerr effect nonlinear coefficient, and a kerr effect nonlinear refractive index coefficient;
and constructing the Kerr effect nonlinear mathematical model based on the fourth corresponding relation.
3. The method according to claim 1 or 2, wherein the higher order modulated signal is obtained by modulating a higher order quadrature amplitude modulated signal on a plurality of orthogonal sub-carriers, the higher order quadrature amplitude modulated signal being modulated using a coherent optical orthogonal frequency division multiplexing modulation scheme, the rate of the quadrature amplitude modulated signal being greater than the rate of the sub-carriers.
4. A method as claimed in claim 3, further comprising:
Determining a total time period based on the number of subcarriers and the time period of the subcarriers;
Determining the dispersion length of the hollow fiber to be measured based on the total time period and the group velocity dispersion parameter of the hollow fiber to be measured, wherein the lifting multiple between the dispersion length of the hollow fiber to be measured and the single carrier modulation dispersion length is the square number of the subcarriers;
And when the transmission distance of the high-order modulated signal is smaller than the dispersion length, executing the step of receiving the high-order modulated signal transmitted by the hollow fiber to be detected in the transmitting end, and demodulating the high-order modulated signal to obtain a high-order demodulated signal.
5. A hollow fiber kerr effect nonlinear coefficient measuring apparatus, said apparatus comprising:
the demodulation module is used for receiving the high-order modulation signal transmitted by the hollow fiber to be detected in the transmitting end, and demodulating the high-order modulation signal to obtain a high-order demodulation signal;
a mapping module, configured to map the high-order demodulation signal into a constellation diagram, and determine a nonlinear phase shift of the high-order demodulation signal in the constellation diagram;
the characterization module is used for determining the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be detected based on the nonlinear phase shift of the high-order demodulation signal in the constellation diagram and a pre-constructed Kerr effect nonlinear mathematical model;
The optimizing module is used for optimizing the communication performance of the hollow fiber to be tested based on the Kerr effect nonlinear refractive index coefficient of the hollow fiber to be tested;
The mapping module is further configured to cluster mapping points of the high-order demodulation signal in the constellation diagram, and determine a cluster center of the mapping points of the high-order demodulation signal in the constellation diagram;
Determining the central position of the mapping point of the high-order demodulation signal in the constellation diagram based on the position of the clustering center of the mapping point of the high-order demodulation signal in the constellation diagram;
Determining a rotation angle between a mapping point and an origin based on the center position of the mapping point of the high-order demodulation signal in a constellation diagram;
classifying mapping points of the high-order demodulation signals in a constellation diagram according to signal intensity, and determining a plurality of mapping groups, wherein the signal intensity of the mapping points in each mapping group is the same;
And determining an arithmetic average value of the rotation angles of the mapping groups based on the rotation angles of the mapping points in the mapping groups, and taking the arithmetic average value of the rotation angles of the mapping groups as the nonlinear phase shift of the mapping points in the mapping groups.
6. A hollow fiber kerr effect nonlinear coefficient measuring device, characterized in that the device comprises a memory, a processor and a computer program stored on the memory and executable on the processor, the computer program being configured to implement the steps of the hollow fiber kerr effect nonlinear coefficient measuring method according to any one of claims 1 to 4.
7. A storage medium, characterized in that the storage medium is a computer-readable storage medium, on which a computer program is stored, which computer program, when being executed by a processor, realizes the steps of the hollow fiber kerr effect nonlinear coefficient measurement method according to any one of claims 1 to 4.
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