Passive optical network access marking device and method

Abstract

This invention relates to the field of optical fiber network technology, and discloses a passive optical fiber network access marking device and method, comprising: an optical transmitting unit transmitting an optical signal at the access end when a user accesses the network and superimposing identity marking information based on dispersion characteristics; an optical fiber access link receiving the optical signal, and superimposing inherent physical attribute information of the link based on the inherent dispersion effect of the optical fiber access link during the optical signal access process; transmitting the optical signal using an optical fiber transmission link; a photoelectric converter receiving the optical signal at the central office and converting it into an electrical signal; a processing unit preprocessing the electrical signal and extracting dispersion-related signal feature parameters from the preprocessed electrical signal; and an identity marking module identifying the identity marking information based on the signal feature parameters and comparing it with the identity marking information in the optical signal when the user accesses the network to obtain the identity marking result of the access user. This invention can improve access security at the physical layer without adding external optical devices or occupying communication bandwidth.

Description

Technical Field

[0001] This invention relates to the field of optical fiber network technology, and in particular to a passive optical fiber network access marking device and method. Background Technology

[0002] Ethernet Passive Optical Network (EPON) is a PON technology based on Ethernet that can provide various services over Ethernet and is a major technology route for broadband access. In recent years, with the continuous surge in the number of access terminals, its application scenarios have expanded from traditional home broadband to diversified fields such as enterprise leased lines, industrial internet, and smart cities.

[0003] Large-scale user access poses a serious challenge to the security of optical access networks, especially at the physical layer, where threats such as malicious access, unauthorized eavesdropping, and identity spoofing are becoming increasingly prominent. Due to the shared channel characteristics of passive fiber optic networks (PFON), security vulnerabilities can lead to widespread service disruptions and the leakage of sensitive information. Therefore, it is necessary to introduce lightweight and reliable security labeling and authentication methods at the physical layer to enhance the trusted access capabilities of PFON. To address this issue, existing technologies primarily employ the following methods:

[0004] 1. Access control methods based on identity encoding information. The principle of this method is that during optical signal transmission, an identity code is embedded in the message or physical layer modulation signal. The access end or central office equipment determines the legitimacy of the terminal by comparing the identity information. Specific implementations include adding an additional bit sequence to the frame header or introducing a pseudo-random sequence bound to the user during modulation. This method can achieve identity differentiation on existing transmission links and is flexible in deployment. However, this method relies on additional communication resources, requiring additional communication resources and leading to a decrease in effective bandwidth.

[0005] 2. Marking methods based on optical filtering characteristics. This type of method utilizes the inherent spectral or wavelength response characteristics of optical devices to achieve access identification. For example, by introducing a fiber Bragg grating with a specific center wavelength and bandwidth at the user end, the transmission / reflection characteristics of the optical filter cause different access points to exhibit unique spectral responses. The central office can then determine the identity of the corresponding access user by detecting the received spectral characteristics using an optical interferometer. The characteristics generated by this method cannot be easily tampered with and possess a certain degree of physical uniqueness. However, this method requires external optical equipment such as optical filters and optical interferometers, which increases costs and makes deployment difficult.

[0006] 3. Software- or upper-layer protocol-based authentication mechanisms. The principle behind this type of method is that during the access authentication phase, the terminal needs to engage in encrypted challenge-response interaction with the authentication server to verify its legitimacy. This method is mainly implemented through traditional encryption and authentication protocols, such as identity verification mechanisms based on symmetric keys or public key systems. Common schemes include the 802.1X authentication framework and digital certificate authentication based on Public Key Infrastructure (PKI). This type of method can provide strong logical security and is relatively flexible in deployment. However, this method only stays at the upper-layer protocol level. Once the identity code is intercepted or copied, attackers can forge legitimate access, posing a significant security risk, and the security level remains relatively low. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a passive optical fiber network access marking device and method, which can improve access security at the physical layer without adding external optical devices or occupying communication bandwidth.

[0008] To address the aforementioned technical problems, this invention provides a passive optical fiber network access marking device, comprising an optical transmitting unit, an optical fiber access link, an optical fiber transmission link, a photoelectric converter, a processing unit, and an identification marking module.

[0009] The optical transmitting unit transmits an optical signal when a user accesses the network at the access end, and the optical signal is superimposed with identity tag information based on the dispersion characteristics;

[0010] The optical fiber access link serves as the access path for optical signals. During the optical signal access process, the inherent physical attribute information of the link is superimposed based on the inherent dispersion effect of the optical fiber access link.

[0011] The optical fiber transmission link is used to transmit optical signals, and the photoelectric converter receives the optical signals transmitted by the optical fiber transmission link at the central office and converts them into electrical signals.

[0012] The processing unit preprocesses the electrical signal and extracts dispersion-related signal feature parameters from the preprocessed electrical signal.

[0013] The identity marking module identifies identity marking information based on the signal feature parameters and compares it with the identity marking information in the optical signal when the user accesses the system to obtain the identity marking result of the accessing user.

[0014] Furthermore, it includes at least one optical transmitting unit, at least one optical fiber access link, and at least one identity tagging module, wherein the optical fiber access link corresponds one-to-one with the optical transmitting unit, and the identity tagging module corresponds one-to-one with the optical transmitting unit.

[0015] Furthermore, the optical transmitting unit includes an optical transmitter and an identity tag dispersion component. The optical transmitter transmits the optical signal when the user accesses the network, and the identity tag dispersion component changes the group velocity dispersion characteristics of the optical signal, superimposing identity tag information on the original link dispersion characteristics.

[0016] Furthermore, the light emitter is a laser, and the identity marker dispersion component is a fiber Bragg grating.

[0017] Furthermore, it also includes an optical splitter, which splits the optical signal before it is transmitted through the optical fiber transmission link, for coupling multiple access end optical signals.

[0018] Furthermore, the optical splitter is a planar waveguide type or a fused conical type structure.

[0019] Furthermore, based on the inherent dispersion effect of the optical fiber access link superimposed with the inherent physical attribute information of the link, specifically:

[0020] The time-domain waveform and frequency-domain characteristics of the optical signal are updated based on the inherent dispersion, attenuation, and phase noise in the optical fiber access link.

[0021] Furthermore, the processing unit is a digital signal processor, a field-programmable gate array, or a central processing unit.

[0022] Furthermore, the identification of identity marker information based on the aforementioned signal feature parameters specifically includes:

[0023] Based on the signal feature parameters, identification tag information is identified using deep learning networks, support vector machines, cluster analysis, statistical feature matching, or principal component analysis.

[0024] The present invention also provides a passive optical fiber network access marking method, comprising the following steps:

[0025] A first optical signal is sent to the fiber optic network when a user accesses the network. Based on the dispersion characteristics, identity tag information is superimposed on the first optical signal to obtain a second optical signal.

[0026] The second optical signal is accessed, and during the access process of the second optical signal, the inherent physical attribute information of the optical fiber access link is superimposed based on the inherent dispersion effect of the optical fiber access link to obtain the third optical signal;

[0027] The third optical signal is transmitted, and the third optical signal is received at the central office and converted into an electrical signal.

[0028] The electrical signal is preprocessed, and the dispersion-related signal feature parameters are extracted from the preprocessed electrical signal.

[0029] The identity marker information is identified based on the signal feature parameters and compared with the identity marker information in the first optical signal when the user accesses the network to obtain the identity identification result of the accessing user.

[0030] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0031] This invention utilizes the inherent dispersion characteristics of optical fiber links to influence signal generation and their controllable variations, enabling unique identification and marking of access users at the physical layer. This requires no additional external optical devices and does not consume communication bandwidth. Furthermore, this invention relies entirely on the inherent physical characteristics of the optical fiber link itself to complete the marking and marking, exhibiting excellent stability and uniqueness, effectively improving the access security and reliability of passive optical fiber networks at the physical layer. Attached Figure Description

[0032] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0033] Figure 1 This is a frame diagram of a passive optical fiber network access marking device in a preferred embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram of a specific structure of a passive optical fiber network access marking device in a preferred embodiment of the present invention.

[0035] Figure 3 This is a flowchart of the passive optical fiber network access marking method in a preferred embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0037] Reference Figure 1 As shown, the present invention discloses a passive optical fiber network access marking device, comprising: at least one optical transmitting unit, at least one optical fiber access link, an optical splitter, an optical fiber transmission link, a photoelectric converter, a processing unit, and at least one identification marking module.

[0038] The optical transmitting unit transmits downlink or uplink optical signals at the access end when a user accesses the network. These optical signals are superimposed with identity tag information based on dispersion characteristics. The unique identity tag information superimposed on the optical signal based on dispersion characteristics uniquely transforms the optical signal, serving as the starting point for identity tag transmission during user access. Figure 2As shown, the optical transmitting unit in this embodiment includes an optical transmitter and an identity tag dispersion component. The optical transmitter transmits the optical signal when a user accesses the network. The identity tag dispersion component modifies the group velocity dispersion characteristics of the optical signal, superimposing identity tag information on the original link dispersion characteristics, thereby completing the loading of the access point tag. The optical transmitter is a laser, and the identity tag dispersion component is a fiber Bragg grating. Each optical transmitting unit includes a laser and a fiber Bragg grating; that is, the first optical transmitting unit includes a first laser and a first fiber Bragg grating, the second optical transmitting unit includes a second laser and a second fiber Bragg grating, ..., the Nth optical transmitting unit includes an Nth laser and an Nth fiber Bragg grating.

[0039] The optical fiber access link serves as the access path for optical signals. Each optical fiber access link corresponds one-to-one with an optical transmitting unit; one optical transmitting unit corresponds to one optical fiber access link. In this embodiment, taking N optical transmitting units (denoted as the first optical transmitting unit, the second optical transmitting unit, ..., the Nth optical transmitting unit) as an example, there are corresponding N optical fiber access links (denoted as the first optical fiber access link, the second optical fiber access link, ..., the Nth optical fiber access link). The link dispersion characteristics of the optical fiber access link have inherent differences in user access points, providing a source of physical layer difference information for identity marking. During the optical signal access process, the inherent physical attribute information of the link is superimposed based on the inherent dispersion effect of the optical fiber access link. The time-domain waveform and frequency-domain characteristics of the optical signal are updated according to the inherent dispersion, attenuation, and phase noise characteristics in the optical fiber access link, thereby enabling the optical signal to carry dispersion information related to the link. The process of superimposing the inherent physical attribute information of the link does not depend on external equipment.

[0040] An optical splitter splits the optical signal before it is transmitted through the optical fiber transmission link, and is used to couple multiple access point optical signals. In this embodiment, the optical splitter is a planar waveguide (PLC) or fused biconical tapered (FBT) structure.

[0041] The optical fiber transmission link is used to transmit the split optical signal and amplifies the inherent physical properties of the optical fiber access link during the transmission of the optical signal.

[0042] The photoelectric converter receives downlink or uplink optical signals transmitted by the access user through the optical fiber transmission link at the central office and converts them into electrical signals for subsequent digital processing and analysis.

[0043] The processing unit preprocesses the electrical signal, including operations such as filtering, normalization, and time-domain / frequency-domain transformation. It then extracts dispersion-related signal characteristic parameters from the preprocessed electrical signal, such as pulse broadening, inter-symbol interference characteristics, and spectral distortion parameters. In this embodiment, the processing unit is a digital signal processor (DSP), a field-programmable gate array (FPGA), or a central processing unit (CPU).

[0044] The identity marking module corresponds one-to-one with each optical transmitting unit. In this embodiment, N optical transmitting units correspond to N identity marking modules (denoted as the first identity marking module, the second identity marking module, ..., the Nth identity marking module). Based on the signal characteristic parameters, signal differences caused by link dispersion are classified and identified to determine identity marking information. This information is then compared with the identity marking information in the optical signal at the time of user access to obtain the user's identity identification result. Based on the signal characteristic parameters, pattern recognition or feature classification algorithms such as deep learning networks, support vector machines, cluster analysis, statistical feature matching, or principal component analysis are used to identify identity marking information. One optical transmitting unit, one optical fiber access link, and one identity marking module form a group for marking one type of user access identity. Finally, the first identity marking module identifies the first identity marking information corresponding to the first optical transmitting unit, the second identity marking module identifies the second identity marking information corresponding to the second optical transmitting unit, ..., the Nth identity marking module identifies the Nth identity marking information corresponding to the Nth optical transmitting unit. The identity marking signal is used to mark the corresponding user access link or device and can be returned to the upper-level management system or security control module as the result of system authentication. In this way, the present invention enables the identification and authentication process to be completed without the need for additional hardware devices, relying solely on the inherent dispersion characteristics of the optical fiber link.

[0045] This invention also discloses a passive optical fiber network access marking method, such as... Figure 3 As shown, it includes the following steps:

[0046] S1: A laser is used to send the first optical signal to the fiber optic network when a user accesses the network. The laser, as the source of the optical signal, primarily provides a stable, continuous optical signal with a certain bandwidth to ensure that the signal fully reflects the dispersion characteristics of the fiber optic link during transmission. In this embodiment, a narrow-linewidth distributed feedback laser or an external cavity laser can be selected to achieve controllable spectral characteristics and good signal coherence, thereby providing high-quality input for subsequent extraction of dispersion features.

[0047] S2: The first optical signal is superimposed with identification information using a fiber Bragg grating to obtain a second optical signal. The optical signal emitted by the laser is processed by a fiber Bragg grating, which modulates the wavelength or performs narrowband filtering on the input optical signal to form an optical signal with specific wavelength distribution characteristics. This signal will be affected by the inherent dispersion effect of the link during subsequent transmission, thus exhibiting unique dispersion response characteristics at the output end. By introducing a fiber Bragg grating, not only can the dispersion characteristics be enhanced in the signal, but precise control of the initial state of the signal can also be achieved, providing a clearer characteristic reference for identification.

[0048] S3: The second optical signal is accessed through the optical fiber access link. During the access process of the second optical signal, the inherent physical attribute information of the link is superimposed according to the inherent dispersion effect of the optical fiber access link to obtain the third optical signal. The third optical signal contains both the inherent physical attribute information of the link and the identity marking information, and is the basic signal for subsequent identity determination.

[0049] The optical signal, processed by a fiber Bragg grating, enters the fiber optic access link. This link typically consists of the access fiber from the user side to the aggregation node and possesses inherent dispersion parameters. Due to differences in manufacturing processes, fiber aging, and environmental stress among different fiber optic access links, their dispersion characteristics are unique. Therefore, the fiber optic access link plays a crucial role as a "physically unreplicable characteristic source" within the system, making it a key component for identity verification.

[0050] S4: The third optical signal is transmitted after being split by an optical splitter. After the third optical signal enters the link through the first optical fiber, it is split by the optical splitter. The main function of the optical splitter is to distribute the power of the optical signal so as to extract part of the signal for identity feature analysis without affecting the transmission of communication services. In this embodiment, the optical splitter can adopt a planar waveguide (PLC) or fused biconical tapered (FBT) structure, and its splitting ratio can be configured according to system requirements to achieve a balance between signal detection and service transmission.

[0051] After the optical signal is split, the third optical signal enters the fiber optic transmission link. The fiber optic transmission link is typically the transmission fiber segment from the aggregation node to the core network, featuring a longer transmission distance and more complex dispersion accumulation effects. Because the accumulation and compensation methods for dispersion differ across different fiber segments, the fiber optic transmission link further amplifies and superimposes the dispersion characteristics from the access link, making the dispersion characteristics in the final output signal more pronounced, effectively enhancing the reliability and uniqueness of the identification tag.

[0052] S5: The third optical signal is received at the central office and converted into an electrical signal using a photoelectric converter. The electrical signal then enters the processing unit. Through this process, the dispersive features and identification information contained in the optical signal are converted into electrical signals, facilitating further digital processing and analysis.

[0053] In this embodiment, the photoelectric converter is typically implemented by a photodetector (such as a PIN photodiode or avalanche photodiode), which converts the optical signal carrying dispersion characteristics into an electrical signal that is easy to process. This electrical signal contains characteristic information such as group delay variation and spectral broadening caused by the inherent dispersion effect of the link, which is the direct basis for identity marking.

[0054] S6: The processing unit preprocesses the electrical signal and extracts the dispersion-related signal feature parameters from the preprocessed electrical signal.

[0055] S7: The identity marking module identifies identity marking information based on the signal feature parameters and compares it with the identity marking information in the first optical signal accessed by the user to obtain the identity marking result of the accessed user.

[0056] Compared with the prior art, the advantages of the present invention are:

[0057] 1. This invention is based on the influence of the inherent dispersion characteristics of optical fiber links on signal generation and their controllable changes. By utilizing the inherent dispersion effect of optical fiber links during transmission, it classifies and identifies dispersion features at the receiving end, achieving unique identification and marking of access users at the physical layer. Different access links differ in length, transmission medium, environmental disturbances, etc., resulting in naturally unique dispersion characteristics. Based on this difference, the inherent physical attributes of the link are used as the carrier of access identification, fundamentally avoiding the drawbacks of traditional methods that require additional embedding of identity information. The resulting effect is that access identification does not occupy communication resources and does not introduce additional bit overhead, thereby ensuring the bandwidth utilization and transmission efficiency of optical fiber communication links.

[0058] 2. The process of superimposing the inherent physical attribute information of the link in this invention is highly endogenous because the marking is accomplished through modulation of the link dispersion effect, rather than relying on external devices. Compared with existing solutions that rely on physical external modules such as optical filters and optical interferometers, this invention avoids the problems of device aging, stability degradation, and additional costs. The overall architecture is simpler, and the complexity of deployment and maintenance is significantly reduced, making it more feasible and practical.

[0059] 3. By using fiber Bragg gratings to superimpose differential marking information related to the access end into the signal, this invention can not only enhance the manifestation of dispersive features in the signal, but also achieve precise control over the initial state of the signal, providing a clearer feature benchmark for identity identification.

[0060] 4. This invention relies entirely on the inherent physical characteristics of the optical fiber link itself to complete the marking and identification, which has excellent stability and uniqueness, and can effectively improve the access security and reliability of passive optical fiber networks at the physical layer.

[0061] 5. This invention converts optical signals into electrical signals using a photoelectric converter at the receiving end, and completes the identification of the identity signal in the post-processing module. This process enables features such as waveform broadening and spectral distortion caused by dispersion to be extracted and analyzed in digital form, providing rich and stable feature information for the subsequent identification process.

[0062] 6. The recognition process is not limited to a single method; it can employ various approaches such as deep learning networks, support vector machines, cluster analysis, and statistical feature matching, demonstrating excellent flexibility and scalability. This not only ensures high recognition accuracy but also allows for the selection of the optimal recognition processing strategy based on different application scenarios and network conditions, thereby improving the system's robustness.

[0063] 7. The solution of this invention has excellent real-time performance. Since identity verification and recognition are both completed during normal optical signal transmission, without requiring additional interaction or complex protocol processes, identity determination can be completed without increasing access latency. Compared with traditional identity authentication methods based on upper-layer software protocols, this significantly shortens authentication time, improves user access experience, and reduces the possibility of security vulnerabilities.

[0064] 8. This invention is inherently adapted to the long-term operating characteristics of fiber optic links. During use, optical fibers are affected by factors such as temperature, humidity, and mechanical disturbances, causing a slow drift in their dispersion characteristics. The identification process in this invention can be updated and adapted to different situations. By periodically or as needed retraining the classification model, the identification process can continuously adapt to environmental changes, ensuring long-term accuracy and reliability.

[0065] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0066] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0067] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0068] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0069] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A passive optical fiber network access marking device, characterized in that: It includes an optical transmitting unit, an optical fiber access link, an optical fiber transmission link, an optoelectronic converter, a processing unit, and an identification module. The optical transmitting unit transmits an optical signal when a user accesses the network at the access end, and the optical signal is superimposed with identity tag information based on the dispersion characteristics; The optical fiber access link serves as the access path for optical signals. During the optical signal access process, the inherent physical attribute information of the link is superimposed based on the inherent dispersion effect of the optical fiber access link. The optical fiber transmission link is used to transmit optical signals, and the photoelectric converter receives the optical signals transmitted by the optical fiber transmission link at the central office and converts them into electrical signals. The processing unit preprocesses the electrical signal and extracts dispersion-related signal feature parameters from the preprocessed electrical signal. The identity marking module identifies identity marking information based on the signal feature parameters and compares it with the identity marking information in the optical signal when the user accesses the system to obtain the identity marking result of the accessing user.

2. The passive optical fiber network access marking device according to claim 1, characterized in that: It includes at least one optical transmitting unit, at least one optical fiber access link, and at least one identification tag module, wherein the optical fiber access link corresponds one-to-one with the optical transmitting unit, and the identification tag module corresponds one-to-one with the optical transmitting unit.

3. The passive optical fiber network access marking device according to claim 1, characterized in that: The optical transmitting unit includes an optical transmitter and an identity tag dispersion component. The optical transmitter transmits the optical signal when the user accesses the network. The identity tag dispersion component changes the group velocity dispersion characteristics of the optical signal and superimposes identity tag information on the original link dispersion characteristics.

4. The passive optical fiber network access marking device according to claim 3, characterized in that: The light emitter is a laser, and the identity marker dispersion component is a fiber Bragg grating.

5. The passive optical fiber network access marking device according to claim 1, characterized in that: It also includes an optical splitter, which splits the optical signal before it is transmitted in the optical fiber transmission link, and is used to couple multiple access end optical signals.

6. The passive optical fiber network access marking device according to claim 5, characterized in that: The optical splitter has a planar waveguide type or a fused conical tapered structure.

7. The passive optical fiber network access marking device according to claim 1, characterized in that: Based on the inherent dispersion effect of the optical fiber access link and the inherent physical attribute information of the link, specifically: The time-domain waveform and frequency-domain characteristics of the optical signal are updated based on the inherent dispersion, attenuation, and phase noise in the optical fiber access link.

8. The passive optical fiber network access marking device according to claim 1, characterized in that: The processing unit is a digital signal processor, a field-programmable gate array, or a central processing unit.

9. The passive optical fiber network access marking device according to any one of claims 1-8, characterized in that: Identifying identity marker information based on the aforementioned signal feature parameters specifically involves: Based on the signal feature parameters, identification tag information is identified using deep learning networks, support vector machines, cluster analysis, statistical feature matching, or principal component analysis.

10. A passive optical fiber network access marking method, characterized in that, Includes the following steps: A first optical signal is sent to the fiber optic network when a user accesses the network. Based on the dispersion characteristics, identity tag information is superimposed on the first optical signal to obtain a second optical signal. The second optical signal is accessed, and during the access process of the second optical signal, the inherent physical attribute information of the optical fiber access link is superimposed based on the inherent dispersion effect of the optical fiber access link to obtain the third optical signal; The third optical signal is transmitted, and the third optical signal is received at the central office and converted into an electrical signal. The electrical signal is preprocessed, and the dispersion-related signal feature parameters are extracted from the preprocessed electrical signal. The identity marker information is identified based on the signal feature parameters and compared with the identity marker information in the first optical signal when the user accesses the network to obtain the identity identification result of the accessing user.

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