Optical fiber network system and method for smart devices

Abstract

The application relates to the technical field of communication, in particular to a fiber network system and method for intelligent equipment. The system comprises a central optical node and a plurality of access optical nodes. The central optical node is arranged in a central computing unit of the equipment, and is internally provided with a laser light source and a power splitting unit. The central optical node outputs the same-wavelength optical carrier to distribute the local oscillation light path and the access optical nodes at each edge gateway. Each access optical node modulates uplink data to different frequency point subcarriers based on the same-source optical carrier to realize uplink frequency domain isolation transmission by FDMA. The central optical node converges multiple uplink optical signals through an optical coupler, a coherent receiver multiplexes the same-source local oscillation light to complete coherent reception and converts the optical signals into electrical signals, and a digital signal processing module analyzes the electrical signals to separate and recover each uplink data. The network architecture of the application is simple, uplink signal interference is avoided by relying on frequency division multiple access, and the coherent reception improves the receiving sensitivity, so that the application is suitable for the internal multi-point fiber high-speed communication scene of intelligent equipment.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a fiber optic network system and method for smart devices. Background Technology

[0002] As the automation and intelligence of various smart devices continue to improve, the number and accuracy of sensors used to collect various signal types such as video, images and sound are constantly increasing, leading to a rapid increase in data interaction traffic within smart devices. This places demands on the communication networks within smart devices for high bandwidth, low latency, low jitter and high reliability.

[0003] Currently, existing smart devices typically employ an Ethernet communication network architecture based on copper cables. In this architecture, various smart devices connect to the Ethernet network through network ports, switches, and controllers, using copper cables as the physical transmission medium. Data, control commands, and status information are carried in the form of electrical signals, enabling point-to-point interconnection between devices. This architecture is relatively mature and has good applicability in low-speed communication scenarios. However, with the continuous increase in communication bandwidth, copper cable transmission media is gradually facing technical bottlenecks. Specifically, copper cables are susceptible to electromagnetic interference when transmitting high-speed electrical signals, requiring electromagnetic compatibility (EMC) design and shielding in complex electromagnetic environments. The weight and cost of high-speed copper cables and their matching connectors increase significantly with the speed, making it difficult to meet engineering requirements in densely wired devices or weight-sensitive applications. Furthermore, copper cables suffer from severe signal attenuation and crosstalk problems during high-speed signal transmission, limiting their further application in high-bandwidth scenarios.

[0004] Compared to copper cable communication, fiber optic communication is unaffected by external electromagnetic interference, possesses excellent transmission characteristics of high bandwidth and low latency, and is lighter and smaller, effectively reducing the overall weight and wiring complexity of cables. Therefore, fiber optic communication can better meet the high-speed communication needs within smart devices, supporting continuous evolution towards higher precision sensors and higher real-time performance, and has become an important development trend in smart device communication networks.

[0005] In existing solutions for applying fiber optic communication technology to smart devices, the existing Passive Optical Network (PON) typically adopts a point-to-multipoint (P2MP, PTMP, or PMP) structure. In the uplink direction, it employs a time-division multiple access (TDMA) mode, where multiple access optical nodes share the same uplink channel. Each access optical node can only transmit uplink data within its allocated time slots. To avoid time-domain conflicts between uplink signals from different access optical nodes, the TDMA architecture requires the introduction of multiple mechanisms such as ranging, time slot scheduling, collision avoidance, registration, dynamic bandwidth allocation, and burst mode reception control. This results in a complex network architecture that struggles to meet the requirements of smart device communication for low latency, high real-time performance, simple structure, and high reliability. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides an optical fiber network system and method for smart devices, based on a frequency division multiple access (FDMA) optical access architecture and uplink access method using the same optical carrier. In uplink communication, multiple optical frequency channels with a defined frequency relationship are generated through the same optical carrier system, enabling different access optical nodes to occupy different spectrum ranges for uplink transmission, without the need for time-shifting transmission as in TDMA mode.

[0007] A first aspect of this application provides a fiber optic network system for smart devices, the fiber optic network system for smart devices comprising: A central optical node is located at the central computing unit of the intelligent device. The central optical node includes a laser source and a power splitting unit. The laser source is used to generate an optical carrier, and the power splitting unit is used to distribute the optical carrier generated by the laser source into multiple paths, which are then transmitted to the local oscillator optical path and multiple access optical nodes, respectively. The plurality of access optical nodes are located at the edge gateway of the smart device. Each access optical node is connected to the central optical node via an optical fiber, and each access optical node modulates an optical carrier with the same wavelength generated by the same laser source from the central optical node. Each of the access optical nodes includes a modulation unit, which is used to modulate the uplink data to be transmitted onto subcarriers of different frequencies on the same optical carrier to generate uplink optical signals, so that the uplink optical signals of different access optical nodes are separated from each other in the frequency domain and share the uplink transmission channel in the frequency division multiple access manner. The central optical node also includes an optical coupler and a coherent receiver. The optical coupler is used to receive and couple uplink optical signals from each of the access optical nodes. The coherent receiver is used to perform photoelectric conversion on the coupled uplink optical signals to convert the uplink optical signals into electrical signals. The central optical node further includes a first digital signal processing module, which is used to perform spectrum analysis on the electrical signal and extract the uplink data of each access optical node from the spectrum of the electrical signal according to the subcarrier frequency point corresponding to each access optical node, so as to recover the uplink data of each access optical node.

[0008] In one optional implementation, the power splitting unit divides the optical carrier generated by the laser source into 1:N paths according to power, where N≥2; one of the 1:N output paths is output as local oscillator light to the coherent receiver, and the remaining N-1 paths are transmitted to the corresponding N-1 access optical nodes through polarization-maintaining fibers. The polarization-maintaining fibers are used to keep the polarization state of the optical carrier stable during transmission, so that the optical carriers received by each access optical node have the same polarization state.

[0009] In an optional implementation, each access optical node further includes a second digital signal processing module, which is used to perform spectrum shaping and frequency shifting processing on the uplink data to be transmitted by each access optical node, so that the uplink optical signals of different access optical nodes occupy non-overlapping spectrum ranges in the frequency domain, and the frequency offset of the subcarrier frequency point of each access optical node relative to the optical carrier is a predetermined fixed value.

[0010] In one optional implementation, the coherent receiver is a zero-difference coherent receiver, wherein the local oscillator and the optical carrier of the uplink optical signal both originate from the same laser source of the central optical node and have the same wavelength. The coherent receiver performs photoelectric conversion on the coupled uplink optical signal through zero-difference coherent reception, converting the uplink optical signal into an electrical signal for subsequent data recovery processing by the digital signal processing module.

[0011] In one optional implementation, the fiber optic network system for the smart device is set up independently of the computing unit of the smart device; the fiber optic network system for the smart device is connected to the computing unit of the smart device through a standard communication interface, and the fiber optic network system for the smart device is provided with an independent power supply interface and a communication management module.

[0012] A second aspect of this application provides a method for a fiber optic network system for smart devices, applied to the aforementioned fiber optic network system for smart devices, the method comprising: The central optical node generates an optical carrier through an internal laser source and distributes the optical carrier into multiple paths through a power splitting unit, which are then transmitted to the local oscillator optical path and multiple access optical nodes respectively. Each of the access optical nodes modulates an optical carrier with the same wavelength generated by the same laser source from the central optical node; Each of the access optical nodes modulates its uplink data to be transmitted onto subcarriers of different frequencies based on the same optical carrier, generating uplink optical signals, so that the uplink optical signals of different access optical nodes are separated from each other in the frequency domain, and multi-path parallel uplink transmission is realized in the frequency division multiple access mode. Each of the access optical nodes transmits the uplink optical signal to the central optical node via optical fiber; The central optical node receives and couples uplink optical signals from each of the access optical nodes through an optical coupler, and converts the optical signals into electrical signals using the local oscillator light that originates from the same laser source as the uplink optical signals. The central optical node performs spectrum analysis on the electrical signal through the first digital signal processing module. Based on the subcarrier frequency points corresponding to each access optical node, it extracts the uplink data of each access optical node from the spectrum of the electrical signal to recover the uplink data of each access optical node.

[0013] In an optional implementation, the step of modulating the respective uplink data to be transmitted onto subcarriers of different frequencies to generate uplink optical signals includes: Each of the access optical nodes acquires the uplink data to be transmitted and converts the uplink data to be transmitted into a digital baseband signal; Each of the access optical nodes performs spectrum shaping processing on the digital baseband signal through a digital signal processing module in order to control the spectral width of the digital baseband signal; Each access optical node uses the digital signal processing module to shift the spectrum-shaped digital baseband signal to the corresponding subcarrier frequency point. The subcarrier frequencies of different access optical nodes are different from each other, and the frequency offset of each subcarrier frequency point relative to the optical carrier is a predetermined fixed value. Each access optical node converts the digital baseband signal moved to the corresponding subcarrier frequency point into an analog modulation signal after digital-to-analog conversion. The analog modulation signal is then used to modulate the optical carrier to generate the uplink optical signal.

[0014] In one optional implementation, the central optical node receives uplink optical signals from each of the access optical nodes through a single coherent receiver and performs photoelectric conversion. The converted electrical signals enter the first digital signal processing module. The first digital signal processing module performs spectrum analysis on the electrical signals and extracts the uplink data of each access optical node from the spectrum of the electrical signals according to the subcarrier frequency points corresponding to each access optical node.

[0015] In one optional implementation, each of the access optical nodes has a different subcarrier frequency configuration, and each access optical node continuously modulates the optical carrier according to its corresponding subcarrier frequency and transmits uplink optical signals.

[0016] In summary, the fiber optic network system and method for smart devices provided in this application have at least one of the following beneficial effects: 1. Each access optical node modulates an optical carrier with the same wavelength generated by the same laser source from the central optical node. Based on this, each access optical node uses its own modulation unit to modulate the uplink data to be transmitted onto subcarriers of different frequencies, generating an uplink optical signal. Because different access optical nodes use different subcarrier frequencies, the uplink optical signals are separated in the frequency domain, allowing multiple access optical nodes to transmit uplink data simultaneously and independently, without needing to take turns transmitting in time, and without signal conflicts. 2. Because the uplink optical signals of each access optical node are naturally separated in the frequency domain, the central optical node, after receiving and coupling the uplink optical signals from each access optical node through an optical coupler, can directly distinguish the data of different nodes in the frequency domain and recover the uplink data of each access optical node. This frequency domain separation characteristic eliminates the need for the system to rely on the protocol mechanisms necessary for TDMA, such as ranging, time slot scheduling, collision avoidance, and registration. 3. The coherent receiver at the central optical node uses the local oscillator light from the local oscillator path for coherent reception. This local oscillator light and the optical carrier of the uplink optical signal originate from the same laser source. Since the local oscillator light and the optical carrier of the uplink optical signal originate from the same laser, the frequency offset and phase noise problems between different lasers are eliminated. Therefore, a zero-difference coherent reception method can be adopted, without the need for additional frequency offset estimation and phase recovery. This significantly improves the signal reception quality and greatly simplifies the processing complexity of the digital signal processing module at the receiver end. At the same time, the uplink optical signals of each access optical node are modulated based on the same wavelength. There is no problem of inconsistent wavelength drift caused by different lasers due to temperature changes or aging in multi-source schemes. This further enhances the long-term stability and reliability of the system in complex temperature environments. Therefore, by using the same laser source to provide co-source optical carriers, FDMA frequency domain separation at each node, and co-source zero-difference coherent reception, each access optical node can transmit uplink data in parallel and independently, while the central optical node can directly distinguish the data from different nodes in the frequency domain. The system eliminates the need for complex protocol mechanisms such as ranging, time slot scheduling, collision avoidance, and registration required in TDMA mode, simplifying the network architecture and significantly reducing protocol overhead. This allows the system to meet the communication requirements of intelligent devices for low latency, high real-time performance, simple structure, and high reliability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the architecture of a fiber optic network system for smart devices, as shown in an embodiment of this application. Figure 2 This is a schematic diagram illustrating a fiber optic network architecture according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating an access optical node supporting multiple types of service interfaces, as shown in an embodiment of this application; Figure 4 This is a schematic diagram of a carrier light source for uplink transmission from a central node, as shown in an embodiment of this application. Figure 5 This is a schematic diagram of an uplink FDMA network structure shown in an embodiment of this application; Figure 6 This is a schematic diagram of a central optical node homogeneous coherent reception according to an embodiment of this application; Figure 7 This is a schematic diagram illustrating a process for preprocessing and spectrum shifting uplink signals based on DSP technology, as shown in an embodiment of this application. Figure 8 This is a schematic flowchart illustrating an optical fiber network communication method according to an embodiment of this application; Figure 9 This is a schematic diagram illustrating an in-vehicle optical fiber communication network architecture based on a central optical node and multiple optical access nodes inside an intelligent electric vehicle, as shown in an embodiment of this application. Figure 10 This is a schematic diagram illustrating an internal optical fiber communication network architecture for an intelligent robot, based on a central optical node and multiple optical access nodes, as shown in an embodiment of this application. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] The following will clearly and completely describe the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this invention can be combined interactively without contradicting each other.

[0020] Reference Figure 1 The diagram shown is an architectural schematic of a fiber optic network system for smart devices according to an embodiment of this application. The fiber optic network system for smart devices is used to realize high-speed, low-latency, low-jitter, and high-reliability data communication between the central computing unit inside the smart device and each edge terminal.

[0021] Refer to together Figure 2 In the fiber optic network system for smart devices provided in this embodiment, the fiber optic network system adopts a multi-point-to-point fiber optic network architecture. Specifically, a central optical node (or root node) is set at the location of the central computing unit of the smart device, and access optical nodes (or leaf optical nodes) are set at the locations of edge gateways. The central optical node and each access optical node are connected via optical fibers and splitters / couplers to achieve optical communication networking. This fiber optic network system for smart devices is networked independently of the computing unit of the smart device. The fiber optic network system for smart devices is set up independently of the computing unit of the smart device, and the fiber optic network system for smart devices is connected to the computing unit through a standard communication interface. The fiber optic network system for smart devices independently completes network communication. That is, this fiber optic network system for smart devices is decoupled from the computing unit of the smart device in both physical form and functional logic, forming an independent fiber optic communication subnet. In terms of physical form, the optical communication devices inside the central optical node, such as the laser source, power splitting unit, optical coupler, and coherent receiver, are hardware-independent from the computing chip of the central computing unit, and are connected through standard communication interfaces (such as PCIe, Ethernet MAC interface, SerDes high-speed serial interface, etc.). In terms of functional logic, the optical signal transmission, optical power distribution, signal modulation and demodulation, spectrum management, and other operations within the fiber optic network system used for intelligent devices are all completed by the fiber optic network system used for intelligent devices itself, without the need for the computing unit to intervene in the control.

[0022] Refer to together Figure 3As shown, the central optical node acts as the root node, connecting to multiple access optical nodes (i.e., leaf optical nodes) via a fiber optic network. Each access optical node is located at the edge gateway of the intelligent device, used to connect various service terminals and realize the access and uplink transmission of multiple types of service data. Specifically, the access optical nodes support multiple service interface types, and the service terminals that can be connected include, but are not limited to: image acquisition devices, such as high-definition cameras, for acquiring video image signals; radar detection devices, such as ultrasonic radar, lidar, and millimeter-wave radar, for acquiring environmental perception signals; various general-purpose sensors, for acquiring multiple physical quantity signals such as temperature, pressure, humidity, and acceleration; electronic skin, for acquiring flexible perception signals such as touch and force; display terminals, for receiving and presenting downlink control commands or data; and execution terminals, for receiving and executing control commands from the central computing unit.

[0023] Because optical fiber communication networks have transparent transmission characteristics, meaning that optical signals do not depend on specific data formats or protocol types during transmission, they can uniformly carry and transparently transmit service data of different rates, formats, and protocols. Therefore, the optical fiber network system in this embodiment can achieve comprehensive access to the above-mentioned service types without configuring dedicated transmission channels or protocol conversion devices for different service types, and has good versatility and scalability.

[0024] Each access optical node aggregates signals from the aforementioned service terminals and transmits them uniformly to the central optical node via the uplink optical communication link. The central computing unit then performs centralized processing and decision-making, thereby achieving efficient aggregation and real-time interaction of multi-source data within the intelligent device.

[0025] It should be noted that the above list of service terminals is for illustrative purposes only and does not constitute a limitation on the scope of protection of this application. Those skilled in the art will understand that any service terminal suitable for fiber optic network access can be connected to the optical access node of this application embodiment through the corresponding interface.

[0026] In this embodiment, the uplink communication between the central optical node and the access optical node adopts a frequency division multiple access (FDMA) access scheme based on the same source optical carrier. The following is a detailed description of the optical fiber network system for smart devices and its uplink communication method in this embodiment.

[0027] Refer to together Figure 2 and Figure 4 The central optical node is located in the central computing unit of the smart device, and it includes a laser source, a power splitting unit, an optical coupler, a coherent receiver, and a digital signal processing (DSP) module (referred to as the first digital signal processing module for easy distinction).

[0028] The laser source is used to generate optical carriers. This laser source serves as the unified light source for the entire fiber optic network system used in smart devices, providing carriers for uplink communication of all access optical nodes, while also providing local oscillator light for coherent reception at the central optical node.

[0029] The power splitting unit is connected to the output of the laser source and is used to distribute the optical carrier generated by the laser source into multiple paths according to power, which are then transmitted to the local oscillator path and multiple access optical nodes. Specifically, the power splitting unit distributes the optical carrier generated by the laser source into 1:N paths according to power, where N≥2. One of the 1:N paths serves as the local oscillator light and is input to the coherent receiver via the local oscillator path; the remaining N-1 paths are transmitted to the corresponding N-1 access optical nodes through polarization-maintaining fibers. The polarization-maintaining fibers are used to maintain the polarization state of the optical carrier during transmission, ensuring that the optical carriers received by each access optical node have the same polarization state.

[0030] The splitting ratio of the power splitting unit can be configured according to the actual application scenario. For example, in scenarios with a large number of access optical nodes, the proportion of optical power allocated to each access optical node can be appropriately increased; in scenarios with a small number of access optical nodes, the proportion of optical power allocated to the local oscillator optical path can be appropriately increased. The specific value of the splitting ratio can be reasonably set by those skilled in the art based on the system link budget.

[0031] An optical coupler is located at the receiving front end of the central optical node. Its input ends are connected to the uplink optical fibers of each access optical node, and its output end is connected to the signal input end of the coherent receiver. The optical coupler is used to receive and couple uplink optical signals from each access optical node, and then send the coupled uplink optical signals to the coherent receiver.

[0032] A coherent receiver is located at the receiving end of the central optical node. It utilizes the local oscillator light, originating from the same laser source as the uplink optical signal's carrier light, to coherently receive the coupled uplink optical signal, converting the optical signal into an electrical signal. This coherent receiver is a zero-difference coherent receiver. Both the local oscillator light and the uplink optical signal's carrier light originate from the same laser source at the central optical node and have the same wavelength. The coherent receiver performs photoelectric conversion on the coupled uplink optical signal using a zero-difference coherent reception method. Since both the local oscillator light and the uplink optical signal's carrier light originate from the same laser source at the central optical node and have the same wavelength, the coherent receiver is a zero-difference coherent receiver. This zero-difference coherent reception method significantly improves signal reception quality and reduces the impact of laser source frequency offset and phase noise.

[0033] The first digital signal processing module is connected to the output of the coherent receiver and is used to perform spectrum analysis on the electrical signal output by the coherent receiver. Based on the subcarrier frequency corresponding to each access optical node, it extracts the uplink data of each access optical node from the spectrum of the electrical signal to recover the uplink data of each access optical node. Since the uplink optical signals of different access optical nodes are separated in the frequency domain, the digital signal processing module can perform spectrum slicing on the received complete spectrum information and recover the uplink data of each access optical node based on the subcarrier frequency position corresponding to each access optical node, thereby realizing the reception of multiple parallel uplink data.

[0034] For the central optical node, it receives uplink optical signals from all access optical nodes through a single coherent receiver and performs photoelectric conversion. The converted electrical signals are then processed uniformly by a digital signal processing module. In terms of physical connection, this fiber optic network system for smart devices achieves multi-point-to-point access, meaning multiple access optical nodes converge to a single receiver on the same central optical node via optical fibers and couplers, offering the low-cost advantage of a multi-point-to-point structure. At the logical communication level, since each access optical node occupies a different spectrum range and communicates directly with the central optical node, the interaction between each access optical node and the central optical node logically achieves a similar effect to point-to-point real-time communication, exhibiting strong real-time performance and determinism.

[0035] Refer to together Figure 2 , Figure 5 and Figure 7 Multiple access optical nodes are located at the edge gateway of the smart device, and each access optical node is connected to the central optical node via optical fiber. Each access optical node modulates an optical carrier with the same wavelength generated by the same laser source from the central optical node.

[0036] Each access optical node includes a modulation unit. In some embodiments, each access optical node further includes a digital signal processing module (referred to as a second digital signal processing module for ease of distinction) and a digital-to-analog converter (DAC). The second digital signal processing module performs spectrum shaping and frequency shifting processing on the uplink data to be transmitted by each access optical node, so that the uplink optical signals of different access optical nodes occupy non-overlapping frequency ranges in the frequency domain, and the frequency offset of the subcarrier frequency of each access optical node relative to the optical carrier is a predetermined fixed value. Specifically, the access optical nodes receive an optical carrier from the central optical node. This optical carrier is distributed by the power splitting unit of the central optical node and transmitted to each access optical node through polarization-maintaining fiber. All access optical nodes receive an optical carrier from the same laser source, with the same wavelength and the same polarization state. Then, the access optical nodes acquire the uplink data to be transmitted. Figure 3As shown, the uplink data of the access optical node originates from various service terminals connected to it, including but not limited to video image signals captured by high-definition cameras, radar signals captured by ultrasonic radar / liquid radar / millimeter-wave radar, physical quantity signals captured by various sensors, and tactile / force signals captured by electronic skin. Furthermore, the access optical node preprocesses the uplink data to be transmitted through a second digital signal processing module. For example... Figure 7 As shown, after the digital signal from the external data signal source enters the second digital signal processing module, it first uses signal spectrum shaping technology to control the signal's spectral width to suppress out-of-band spectral leakage, thus limiting the signal's spectral width to a preset range. Then, spectrum shifting technology shifts the signal to be transmitted to the corresponding subcarrier frequency. Each access optical node has a different subcarrier frequency configuration; the subcarrier frequencies of different access optical nodes are different, and the frequency offset of each subcarrier frequency relative to the optical carrier is a predetermined fixed value, thereby ensuring that the uplink optical signals of different access optical nodes occupy non-overlapping spectral ranges in the frequency domain. Subsequently, the access optical nodes convert the spectrum-shifted digital signal into an analog electrical signal via a digital-to-analog converter, and then use this analog electrical signal to modulate the optical carrier from the central optical node through a modulation unit to generate the uplink optical signal.

[0037] In this way, the modulation units of each access optical node modulate their respective uplink data to be transmitted onto subcarriers of different frequencies on the same optical carrier, generating uplink optical signals. Since the subcarrier frequencies of each access optical node are different, the uplink optical signals of different access optical nodes are separated in the frequency domain, sharing the uplink transmission channel in a frequency division multiple access manner.

[0038] See also Figure 5 and Figure 6 Each access optical node transmits its generated uplink optical signal to the central optical node via optical fiber. For example... Figure 5 As shown, different access optical nodes modulate data onto subcarriers in different frequency bands based on FDMA frequency division multiplexing technology. The frequency offset of each access optical node relative to the light source carrier is a constant value, ensuring that the crosstalk of the optical signals of each node in the frequency domain is minimal after uplink aggregation.

[0039] At the central optical node, a passive optical power coupler couples uplink optical signals from different access optical nodes. The uplink optical signals coupled by the passive optical power coupler are then uniformly input to the coherent receiver at the central optical node for photoelectric conversion. For example... Figure 6 As shown, after the light is combined by the passive optical coupler at the central optical node, all modulated optical signals from the access optical nodes enter the coherent receiver. The local oscillator light used for coherent reception at the central optical node and the optical carrier of the uplink optical signal from the access nodes both originate from the same laser, achieving zero-difference coherent reception.

[0040] After the coherent receiver performs photoelectric conversion on the coupled uplink optical signal, it outputs an electrical signal containing uplink data information from each access optical node to the first digital signal processing module at the central optical node. The first digital signal processing module performs spectral analysis on the electrical signal and extracts the uplink data of each access optical node from its spectrum based on the subcarrier frequency corresponding to each access optical node. Since the uplink optical signals of different access optical nodes are separated in the frequency domain, the digital signal processing module can recover the uplink data of each access optical node by performing spectral slicing on the received complete spectral information and based on the subcarrier frequency position corresponding to each access optical node, thereby achieving the reception of multiple parallel uplink data streams.

[0041] Therefore, the working principle of a fiber optic network system used for intelligent devices is as follows: The laser source at the central optical node generates an optical carrier, which is distributed into multiple paths by a power splitter. One path serves as the local oscillator for coherent reception, while the remaining paths are transmitted to each access optical node via polarization-maintaining fiber, providing each access optical node with an optical carrier of the same wavelength and polarization state. Upon receiving the optical carrier from the central optical node, each access optical node processes its uplink data to be transmitted through digital signal processing (spectrum shaping and frequency shifting), digital-to-analog conversion, and then modulates it onto the optical carrier to generate an uplink optical signal. The uplink optical signals from different access optical nodes occupy different subcarrier frequencies, thus separating them in the frequency domain. Each access optical node transmits its generated uplink optical signal through fiber to the central optical node, where it is coupled by a passive optical power coupler and then uniformly enters the coherent receiver. The coherent receiver uses the local oscillator, which originates from the same laser source as the uplink optical signal, for zero-difference coherent reception, converting the optical signal into an electrical signal. The first digital signal processing module of the central optical node performs spectrum analysis on the electrical signal output by the coherent receiver, extracting the uplink data of each access optical node from the spectrum of the electrical signal to complete the uplink communication. Since each access optical node accesses in parallel through different frequency channels and communicates directly with the central optical node within its own spectrum range, there is no time slot scheduling, ranging, collision avoidance, and registration process as required by TDMA mode. There are no delay changes or jitter during communication, resulting in a simple network architecture, low access latency, strong real-time performance, and high reliability.

[0042] Reference Figure 8 The diagram shown is a flowchart illustrating an optical fiber network communication method according to an embodiment of this application. The optical fiber network communication method is applied to smart devices and can be implemented based on the optical fiber network system for smart devices described above. The optical fiber network communication method includes the following steps.

[0043] S81, the central optical node generates an optical carrier through an internal laser light source, and distributes the optical carrier into multiple paths through a power beam splitting unit, which are then transmitted to the local oscillator optical path and multiple access optical nodes respectively.

[0044] The central optical node generates optical carriers through its laser source and distributes these optical carriers into multiple paths according to power using a power splitting unit. For example... Figure 3 As shown, after the laser source at the central optical node is powered on, it generates a continuous optical carrier. This optical carrier enters the power splitting unit, which distributes the optical carrier into 1:N paths (N≥2) according to power. One path is used as the local oscillator light input to the coherent receiver at the central optical node, and the remaining N-1 paths are transmitted to the corresponding access optical nodes through polarization-maintaining fibers.

[0045] S82, each of the access optical nodes modulates an optical carrier with the same wavelength generated by the same laser source from the central optical node.

[0046] Each access optical node receives an optical carrier from the central optical node via polarization-maintaining fiber. Since all optical carriers originate from the same laser source, the optical carriers received by all access optical nodes have the same wavelength. Furthermore, due to the use of polarization-maintaining fiber transmission, the optical carriers received by each access optical node also have the same polarization state.

[0047] S83, each of the access optical nodes modulates its own uplink data to be transmitted onto subcarriers of different frequencies based on the same optical carrier, generating uplink optical signals, so that the uplink optical signals of different access optical nodes are separated from each other in the frequency domain, and multi-path parallel uplink transmission is realized in the frequency division multiple access mode.

[0048] Each access optical node first acquires the uplink data to be transmitted, which originates from the service terminal (e.g., ...) connected to each access optical node. Figure 3 (As shown), including but not limited to video data acquired by cameras, point cloud data acquired by radar, and physical quantity data acquired by sensors. Each access optical node sends the acquired uplink data to the digital signal processing module. After spectrum shaping and spectrum shifting, it generates an analog modulation signal through digital-to-analog conversion. This analog modulation signal is then used to modulate the same optical carrier from the central optical node to generate an uplink optical signal. Since the subcarrier frequencies of different access optical nodes are different, the uplink optical signals generated by each access optical node are separated in the frequency domain, thereby achieving multi-path parallel uplink transmission using frequency division multiple access.

[0049] In an optional implementation, modulating the respective uplink data to be transmitted onto subcarriers of different frequencies to generate uplink optical signals includes: Each of the access optical nodes acquires the uplink data to be transmitted and converts the uplink data to be transmitted into a digital baseband signal; Each of the access optical nodes performs spectrum shaping processing on the digital baseband signal through a digital signal processing module in order to control the spectral width of the digital baseband signal; Each access optical node uses the digital signal processing module to shift the spectrum-shaped digital baseband signal to the corresponding subcarrier frequency point. The subcarrier frequencies of different access optical nodes are different from each other, and the frequency offset of each subcarrier frequency point relative to the optical carrier is a predetermined fixed value. Each access optical node converts the digital baseband signal moved to the corresponding subcarrier frequency point into an analog modulation signal after digital-to-analog conversion. The analog modulation signal is then used to modulate the optical carrier to generate the uplink optical signal.

[0050] In some embodiments, see also Figure 7 Each access optical node acquires the uplink data to be transmitted. The uplink data originates from the service terminals connected to each access optical node (such as…). Figure 3 As shown, the uplink data includes video data acquired by cameras, point cloud data acquired by radar, and physical quantity data acquired by sensors. Each access optical node converts the acquired uplink data into a digital baseband signal and sends it to the digital signal processing module for processing. The digital signal processing module performs spectrum shaping on the digital baseband signal, controls the signal's spectral width, and then shifts the signal to the corresponding subcarrier frequency using spectrum shifting technology. Different access optical nodes are configured with different subcarrier frequencies, and the frequency offset of each subcarrier frequency relative to the optical carrier is a predetermined fixed value. Next, each access optical node sends the spectrum-shifted digital signal to a digital-to-analog converter to convert it into an analog modulation signal. Finally, the modulation unit of each access optical node uses this analog modulation signal to modulate the optical carrier from the central optical node, generating an uplink optical signal. Because different access optical nodes use different subcarrier frequencies for modulation, the uplink optical signals generated by each access optical node are separated in the frequency domain, and each node occupies non-overlapping spectrum segments in parallel.

[0051] S84, each of the access optical nodes transmits the uplink optical signal to the central optical node via optical fiber.

[0052] Each access optical node transmits the modulated uplink optical signal to the central optical node via uplink fiber. For example... Figure 5 As shown, uplink optical signals from different access optical nodes are transmitted independently in the optical fiber, each carrying modulation information of different subcarrier frequencies.

[0053] S85, the central optical node receives and couples uplink optical signals from each of the access optical nodes through an optical coupler, and converts the optical signals into electrical signals using the local oscillator light that originates from the same laser source as the uplink optical signals.

[0054] S86, the central optical node performs spectrum analysis on the electrical signal through the first digital signal processing module, and extracts the uplink data of each access optical node from the spectrum of the electrical signal according to the subcarrier frequency point corresponding to each access optical node, so as to recover the uplink data of each access optical node.

[0055] See Figure 5 and Figure 6 After the uplink optical signals from each access optical node are transmitted to the central optical node, they first enter the passive optical power coupler. The passive optical power coupler couples the uplink optical signals from different access optical nodes into a single optical signal, which is then output to the coherent receiver.

[0056] The coherent receiver receives the coupled uplink optical signal and simultaneously receives the local oscillator light from the local oscillator path. This local oscillator light and the optical carrier of the uplink optical signal originate from the same laser source at the central optical node, and they have the same wavelength and phase relationship. The coherent receiver uses the local oscillator light to perform zero-difference coherent reception of the coupled uplink optical signal, converting the optical signal into an electrical signal.

[0057] During coherent reception, the coherent receiver performs photoelectric conversion on the combined local oscillator light and uplink optical signal, outputting an electrical signal containing uplink data information from each access optical node to the digital signal processing module (i.e., the first digital signal processing module) at the central optical node. The digital signal processing module performs spectral analysis on the electrical signal, extracting the uplink data of each access optical node from the complete spectrum based on the subcarrier frequency position corresponding to each access optical node, thereby completing the recovery of the uplink data from each access optical node. Since the uplink optical signals of each access optical node are separated in the frequency domain, the central optical node can simultaneously extract and process the uplink data from multiple nodes in parallel, based on the subcarrier frequency configuration of each node, thus realizing multi-channel parallel uplink communication.

[0058] Therefore, the central optical node receives uplink optical signals from all access optical nodes through a single coherent receiver, realizing multi-point-to-point access in terms of physical connection, and realizing point-to-point real-time communication between each access optical node and the central optical node in terms of logical communication. The communication between each access optical node and the central optical node does not have the waiting delay and latency jitter caused by time slot scheduling, ranging, collision avoidance or registration process based on time division multiple access.

[0059] Through steps S81 to S86 above, this embodiment realizes FDMA uplink communication based on co-source optical carriers. In this embodiment, each access optical node exclusively occupies a communication spectrum and conducts point-to-point real-time communication with the central optical node within its respective spectrum range, enabling the immediate transmission of external sensor data. Compared with the TDMA time division multiple access method commonly used in PON uplink communication, this embodiment eliminates the need for complex protocols such as ranging, collision avoidance, registration, and time slot allocation, resulting in a simpler network architecture. Furthermore, since there is no waiting or jitter caused by TDMA time slot scheduling, this embodiment can significantly reduce communication latency and latency jitter. Furthermore, for the central optical node, it receives uplink optical signals from all access optical nodes through a single coherent receiver. In terms of physical connection, multiple access optical nodes converge to a single receiver on the same central optical node via optical fibers and couplers, achieving point-to-point access and possessing the low-cost advantage of a point-to-point structure. At the logical communication level, since each access optical node occupies a different spectrum range and communicates directly with the central optical node, point-to-point real-time communication is achieved between the access optical nodes and the central optical node, exhibiting strong real-time performance and determinism. Further, in the uplink communication of this embodiment, all modulated optical signals from the access optical nodes uniformly enter the coherent receiver of the central optical node. Since the local light source of the central optical node and the uplink optical signals from the access nodes originate from the same laser, a coherent reception method with zero difference between sources can be adopted, significantly improving signal reception quality. Simultaneously, the uplink signals from each access optical node are modulated based on the same wavelength, eliminating wavelength deviation issues between different light sources. Therefore, it is less susceptible to wavelength drift caused by temperature changes, further enhancing system stability and reliability. Therefore, the technical solution provided in this embodiment achieves a simpler network architecture, lower access latency, stronger real-time performance, and higher reliability, and is suitable for realizing high-bandwidth and low-latency optical communication networks between smart devices.

[0060] To facilitate understanding of the inventive concept of this application, intelligent electric vehicles and intelligent robots are used as examples of intelligent devices to describe the fiber optic communication network system proposed in this embodiment. Those skilled in the art should understand that intelligent electric vehicles and intelligent robots are merely illustrative examples and do not constitute a limitation of this application.

[0061] Example 1: In this embodiment, the smart device is a smart electric vehicle. Figure 9This diagram illustrates the in-vehicle fiber optic communication network architecture of an intelligent electric vehicle, consisting of a central optical node and multiple optical access nodes. In this architecture, the area containing the central computing unit is designated as the central optical node, while optical access nodes can be installed in areas such as the front, rear, left side, right side, and cabin. Each optical access node connects to an edge gateway within its area to aggregate in-vehicle sensor data and upload it to the central optical node via an in-vehicle fiber optic link.

[0062] Taking the front of the vehicle as an example, the optical access node at the front can connect to sensor devices such as forward-facing LiDAR, forward-looking high-definition cameras, millimeter-wave radar, and ultrasonic radar. Optical access nodes on both sides of the vehicle can connect to devices such as side-facing high-definition cameras, side-facing LiDAR, blind spot monitoring radar, and door or body status sensors. The optical access node at the rear of the vehicle can connect to devices such as rear-facing high-definition cameras, rear-facing millimeter-wave radar, parking assist sensors, and rear environmental perception units. Optical access nodes in the cabin or chassis area can connect to devices such as in-cabin cameras, driver monitoring sensors, chassis control feedback units, and vehicle status monitoring units. Through this setup, perception data, status data, and control feedback data distributed across different areas of the vehicle can all be connected to the in-vehicle fiber optic network via the corresponding optical access nodes.

[0063] During uplink communication, a unified laser source in the central optical node first generates the optical carrier required for uplink communication. This optical carrier is split into multiple paths by a power splitting unit. A portion of it is retained inside the central optical node as the local oscillator light for the coherent receiver; the remaining portion is transmitted to each optical access node through the in-vehicle polarization-maintaining fiber link, so that the optical access nodes at the front, rear, sides of the vehicle, and cabin area all receive the optical carrier generated by the same laser source.

[0064] After receiving the optical carrier from the central optical node, each optical access node uplinks and modulates the data output by sensors or edge gateways within its area. For example, point cloud data from forward-looking LiDAR, video or image data from high-definition cameras, target detection data from millimeter-wave radar, and status feedback data from chassis, battery, and body control units first enter the digital signal processing module in the corresponding optical access node. This module encodes, shapes the spectrum, and shifts the frequency of the data to be uploaded, ensuring that the data from different optical access nodes are within different uplink frequency ranges. Subsequently, the processed digital signal is converted into an analog electrical signal by a digital-to-analog converter and drives a modulator to modulate the same-source optical carrier from the central optical node, thereby forming an uplink modulated optical signal in the corresponding frequency band.

[0065] Optical access nodes in different vehicle areas perform frequency division multiple access (FDMA) uplink transmission according to a preset spectrum allocation scheme. For example, the optical access node at the front of the vehicle can occupy the first uplink frequency band to upload data from the forward-facing LiDAR, forward-facing HD camera, and forward-facing millimeter-wave radar; the optical access node on the left side of the vehicle can occupy the second uplink frequency band to upload data from the left-side camera, side radar, and vehicle status; the optical access node on the right side of the vehicle can occupy the third uplink frequency band; and the optical access node at the rear of the vehicle can occupy the fourth uplink frequency band to upload data from the rear-view camera, parking radar, and rear environmental perception. Because each optical access node occupies different spectrum resources, data from each area can be uploaded in parallel within the vehicle-mounted fiber optic communication network.

[0066] The uplink modulated optical signals output from each optical access node are transmitted back to the central optical node via the vehicle's internal fiber optic link, and then combined at the passive aggregation node of the central optical node using a passive optical coupler. The combined uplink optical signal contains multiple spectral components from the front, rear, sides of the vehicle, and the cabin area. This combined optical signal enters the coherent receiver of the central optical node and is coherently mixed with the local oscillator light retained by the central optical node. Since the local oscillator light and the optical carriers used for modulation by each optical access node all originate from the same laser source, the central optical node can achieve coherent reception with zero difference from the same source, reducing the impact of laser source frequency offset and phase noise.

[0067] The coherently received electrical signal enters the receiver digital signal processing module in the central optical node. Based on the spectral position corresponding to different optical access nodes, the receiver digital signal processing module performs frequency domain separation, filtering, demodulation, and data recovery operations on the composite uplink signal, thereby obtaining LiDAR point cloud data, high-definition camera image data, millimeter-wave radar target data, vehicle status data, chassis feedback data, and cabin monitoring data, respectively. The central computing unit can then perform environmental perception, target recognition, path planning, vehicle control, and intelligent driving decision-making based on the recovered multi-source data.

[0068] Through the above implementation method, multiple edge access optical nodes inside the intelligent electric vehicle can simultaneously upload data to the central computing unit in a frequency division multiplexing manner, reducing the waiting latency and latency jitter caused by time slot scheduling based on traditional time division multiplexing, improving the real-time upload capability of high-bandwidth sensor data such as lidar, high-definition cameras, and millimeter-wave radar, and meeting the requirements of intelligent driving and other scenarios for high-bandwidth, low-latency and high-reliability vehicle communication.

[0069] Example 2: In this embodiment, the intelligent device is an intelligent robot. Figure 10This diagram illustrates the fiber optic communication network architecture of an intelligent robot, consisting of a central optical node and multiple optical access nodes. In this architecture, the central optical node is located at the robot's central computing unit, while optical access nodes are located at the robot's head, torso, arms, hands, legs, feet, or mobile chassis. Each optical access node is positioned close to different functional terminals of the robot to receive sensor data, actuator feedback data, and local control data from those corresponding parts.

[0070] For humanoid robots, the head-mounted optical access node corresponds to the robot's "eyes" and "hearing" terminals. The robot's eyes can be composed of LiDAR and high-definition cameras, such as head-mounted LiDAR and binocular high-definition cameras, used to acquire point cloud and image information of the surrounding environment. The head can also be equipped with a microphone array and posture sensors for voice acquisition, head posture detection, and environmental perception. The dual-arm optical access node can connect to devices such as robotic arm joint encoders, joint torque sensors, and arm posture sensors. The hand or end effector optical access node can connect to devices such as dexterous hand tactile sensors, fingertip pressure sensors, and end-tool status feedback units. The leg and foot optical access nodes can connect to devices such as leg joint encoders, plantar pressure sensors, foot tactile sensors, inertial measurement units, and gait control feedback units. For wheeled or tracked mobile robots, the chassis optical access node can also connect to chassis motor drivers, wheel speed sensors, obstacle avoidance radar, and power management units.

[0071] During uplink communication, a unified laser source in the central optical node generates an optical carrier for uplink transmission within the robot. This optical carrier is split into multiple paths by a power splitter. One portion is retained in the central optical node as the local oscillator light for the coherent receiver, while the other portion is transmitted via internal fiber optic links to optical access nodes at the head, arm, hand, leg, foot, and chassis. Thus, each optical access node receives an optical carrier of the same wavelength generated by the same laser source.

[0072] After receiving the optical carrier from the central optical node, each optical access node uplinks the data generated by its local sensor or actuator feedback unit. Taking the head optical access node as an example, the point cloud data generated by the head lidar, the video image data generated by the high-definition camera, and the audio data generated by the microphone array first enter the digital signal processing module in the head optical access node. This digital signal processing performs operations such as data encoding, spectrum shaping, and frequency shifting, and shifts the head-sensing data to a preset first uplink frequency band. Subsequently, the processed signal is converted from digital to analog and then drives the optical modulator to modulate the same source optical carrier sent by the central optical node, forming the uplink modulated optical signal corresponding to the head-sensing data. For the robot's two arms and two hands, the left arm optical access node can shift the left arm joint angle, joint torque, wrist force sensor, and left hand tactile feedback data to the second uplink frequency band; the right arm optical access node can shift the right arm joint state, end effector position, dexterous hand tactile and gripping force feedback data to the third uplink frequency band. For the robot's legs and feet, the optical access nodes at the legs or feet can transfer leg joint encoder data, plantar pressure data, gait feedback data, and inertial measurement data to the fourth or fifth uplink frequency band. For the torso or chassis, the relevant optical access nodes can transfer body posture, power status, motor drive feedback, and chassis motion status data to other preset uplink frequency bands. After the above processing, the optical access nodes at different parts of the robot, such as the head, arms, hands, legs, feet, and chassis, generate uplink modulated optical signals in different spectral ranges. These uplink modulated optical signals are transmitted back to the central optical node through the robot's internal fiber optic link and combined at the passive convergence node of the central optical node. The combined uplink optical signal contains multiple spectral components, each corresponding to data from a part of the robot or a type of functional terminal, such as head "eye" perception data, hand tactile feedback data, robotic arm force control data, leg gait data, and foot contact feedback data.

[0073] After the composite uplink optical signal enters the coherent receiver in the central optical node, it is coherently received with the local oscillator light retained by the central optical node. Since the local oscillator light and the optical carriers modulated by each optical access node all originate from the same laser source, there are no laser source frequency offset or phase noise issues between the optical access nodes inside the robot. The coherently received electrical signal enters the receiver's digital signal processing module. The receiver's digital signal processing module performs frequency domain separation, filtering, demodulation, and data recovery operations on the signals of different frequency bands according to a preset spectrum allocation relationship, obtaining data from the robot's eye perception terminal, hand operation terminal, leg motion terminal, foot contact terminal, and torso status terminal, respectively.

[0074] Through the above implementation method, the robot's internal devices, such as LiDAR, high-definition cameras, tactile sensors, force sensors, joint encoders, foot pressure sensors, and motor feedback units, can upload data to the central computing unit in parallel. The robot's central computing unit can obtain environmental perception information, hand operation feedback, leg movement status, and foot contact status in real time, and perform tasks such as visual recognition, path planning, robotic arm force control, dexterous hand grasping, posture balance, gait control, and obstacle avoidance decision-making accordingly.

[0075] This robot fiber optic communication network is suitable for high real-time control scenarios. For example, humanoid robots need to simultaneously acquire environmental information from head-mounted LiDAR and cameras, leg joint states, foot pressure feedback, and body posture information during walking; robotic arms need to simultaneously acquire visual positioning information, wrist force feedback, and finger tactile information when grasping objects; and mobile robots need to simultaneously acquire LiDAR point clouds, camera images, and chassis motion feedback during obstacle avoidance. By adopting frequency division multiple access uplink communication, data from different parts can be uploaded simultaneously within their respective frequency bands, reducing time slot waiting and uplink conflicts, and improving the real-time performance of the robot's perception, decision-making, and control closed loop.

[0076] Furthermore, robots typically contain numerous motor drivers, power modules, joint actuators, and high-frequency control circuits, creating a complex electromagnetic environment. Using fiber optics as the high-speed communication link within the robot improves its resistance to electromagnetic interference and leverages the lightweight and small size of fiber optics to meet the wiring needs of robot joints, arms, legs, feet, and torso where space is limited. Since all optical access nodes share the same optical carrier from the central optical node, this architecture also reduces the wavelength management complexity associated with multi-source configurations, improving communication stability and reliability during long-term robot operation.

[0077] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0078] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0079] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A fiber optic network system for smart devices, characterized in that, The fiber optic network system for smart devices includes: A central optical node is located at the central computing unit of the intelligent device. The central optical node includes a laser source and a power splitting unit. The laser source generates an optical carrier, and the power splitting unit distributes the optical carrier generated by the laser source into multiple paths, which are then transmitted to the local oscillator path and multiple access optical nodes, respectively. The power splitting unit divides the optical carrier generated by the laser source into 1:N paths according to power, where N≥2. One of the 1:N output paths is used as the local oscillator light output to a coherent receiver, and the remaining N-1 paths are transmitted to the corresponding N-1 access optical nodes through polarization-maintaining fibers. The polarization-maintaining fibers are used to maintain the polarization state of the optical carrier during transmission, so that the optical carriers received by each access optical node have the same polarization state. The plurality of access optical nodes are located at the edge gateway of the smart device. Each access optical node is connected to the central optical node via an optical fiber, and each access optical node modulates an optical carrier with the same wavelength generated by the same laser source from the central optical node. Each of the access optical nodes includes a modulation unit, which is used to modulate the uplink data to be transmitted onto subcarriers of different frequencies on the same optical carrier to generate uplink optical signals, so that the uplink optical signals of different access optical nodes are separated from each other in the frequency domain and share the uplink transmission channel in the frequency division multiple access manner. The central optical node further includes an optical coupler and a coherent receiver. The optical coupler is used to receive and couple uplink optical signals from each of the access optical nodes. The coherent receiver is used to perform photoelectric conversion on the coupled uplink optical signals, converting the uplink optical signals into electrical signals. The coherent receiver is a zero-difference coherent receiver. The local oscillator and the optical carrier of the uplink optical signals both originate from the same laser source of the central optical node and have the same wavelength. The coherent receiver performs photoelectric conversion on the coupled uplink optical signals through zero-difference coherent reception, converting the uplink optical signals into electrical signals for subsequent data recovery processing by the digital signal processing module. The central optical node further includes a first digital signal processing module, which is used to perform spectrum analysis on the electrical signal and extract the uplink data of each access optical node from the spectrum of the electrical signal according to the subcarrier frequency point corresponding to each access optical node, so as to recover the uplink data of each access optical node. Each of the access optical nodes further includes a second digital signal processing module. The second digital signal processing module is used to perform spectrum shaping and frequency shifting processing on the uplink data to be transmitted by each access optical node, so that the uplink optical signals of different access optical nodes occupy non-overlapping spectrum ranges in the frequency domain, and the frequency offset of the subcarrier frequency point of each access optical node relative to the optical carrier is a predetermined fixed value. The fiber optic network system for the smart device is set up independently of the computing unit of the smart device; the fiber optic network system for the smart device is connected to the computing unit of the smart device through a standard communication interface, and the fiber optic network system for the smart device is equipped with an independent power supply interface and a communication management module.

2. A fiber optic network communication method, characterized in that, The fiber optic network communication method, applied to the fiber optic network system for smart devices according to claim 1, comprises: The central optical node generates an optical carrier through an internal laser source and distributes the optical carrier into multiple paths through a power splitting unit, which are then transmitted to the local oscillator optical path and multiple access optical nodes respectively. Each of the access optical nodes modulates an optical carrier with the same wavelength generated by the same laser source from the central optical node; Each of the access optical nodes modulates its uplink data to be transmitted onto subcarriers of different frequencies based on the same optical carrier, generating uplink optical signals, so that the uplink optical signals of different access optical nodes are separated from each other in the frequency domain, and multi-path parallel uplink transmission is realized in the frequency division multiple access mode. Each of the access optical nodes transmits the uplink optical signal to the central optical node via optical fiber; The central optical node receives and couples uplink optical signals from each of the access optical nodes through an optical coupler, and converts the optical signals into electrical signals using the local oscillator light that originates from the same laser source as the uplink optical signals. The central optical node performs spectrum analysis on the electrical signal through the first digital signal processing module. Based on the subcarrier frequency points corresponding to each access optical node, it extracts the uplink data of each access optical node from the spectrum of the electrical signal to recover the uplink data of each access optical node.

3. The optical fiber network communication method according to claim 2, characterized in that, The step of modulating the respective uplink data to be transmitted onto subcarriers of different frequencies to generate uplink optical signals includes: Each of the access optical nodes acquires the uplink data to be transmitted and converts the uplink data to be transmitted into a digital baseband signal; Each of the access optical nodes performs spectrum shaping processing on the digital baseband signal through a digital signal processing module in order to control the spectral width of the digital baseband signal; Each access optical node uses the digital signal processing module to shift the spectrum-shaped digital baseband signal to the corresponding subcarrier frequency point. The subcarrier frequencies of different access optical nodes are different from each other, and the frequency offset of each subcarrier frequency point relative to the optical carrier is a predetermined fixed value. Each access optical node converts the digital baseband signal moved to the corresponding subcarrier frequency point into an analog modulation signal after digital-to-analog conversion. The analog modulation signal is then used to modulate the optical carrier to generate the uplink optical signal.

4. The optical fiber network communication method according to claim 2, characterized in that, The central optical node receives uplink optical signals from each of the access optical nodes through a single coherent receiver and performs photoelectric conversion. The converted electrical signals enter the first digital signal processing module. The first digital signal processing module performs spectrum analysis on the electrical signals and extracts the uplink data of each access optical node from the spectrum of the electrical signals according to the subcarrier frequency points corresponding to each access optical node.

5. The optical fiber network communication method according to claim 2, characterized in that, Each of the access optical nodes has a different subcarrier frequency configuration. Each access optical node continuously modulates the optical carrier according to its corresponding subcarrier frequency and sends uplink optical signals.

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