A passive optical network system and related devices

Abstract

The present invention provides a passive optical network system and related devices. This passive optical network system uses an optical reflector installed in an optical network (ODN) to optically reflect a first signal sent from a first optical network unit (ONU) to a second optical network unit (ONU). This allows the first signal to reach the second ONU without passing through the optical transmission line (OLT). This implements passive optical switching within a local area, enabling the first ONU to transmit data to the second ONU within the local area. Therefore, the solution of the present invention does not require the OLT, resulting in low latency.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular to a passive optical network system and related devices. Background Art

[0002] Passive optical network (PON) is currently the primary solution for fiber-to-the-home (FTTH). PON access provides sufficient access bandwidth and has advantages such as low deployment cost and simple operation and maintenance.

[0003] Figure 1 This application provides a diagram of the PON architecture. A PON is a single-fiber, bidirectional optical access network using a point-to-multipoint (P2MP) architecture. A PON system consists of an optical line terminal (OLT) at the central office, an optical distribution network (ODN), and optical network units (ONUs) at the user end.

[0004] In data transmission systems, the data transmitted can be described as "north-south traffic" and "east-west traffic." North-south traffic typically refers to traffic between clients and servers, while east-west traffic can refer to traffic between different servers or between different data centers. Specifically, in a PON system, north-south traffic can refer to traffic from the server to the OLT to the ONU, while east-west traffic can refer to traffic between different ONUs. Figure 2 Schematic diagram of north-south flow and east-west flow. Figure 2 The traffic between the server ONUs is north-south traffic, and the traffic between each ONU is east-west traffic.

[0005] like Figure 2 As shown in FIG, if data from ONU1# needs to be transmitted to ONU2#, the data needs to be sent to the OLT first, and then the OLT sends the data to ONU2#. This data transmission method has a large delay and cannot meet the requirement of fast data transmission. Summary of the Invention

[0006] The present invention provides a passive optical network system and related devices. The optical reflectors in the ODN reflect the signals sent from one ONU to another, thus achieving passive optical switching within a local area. The signals do not need to pass through the OLT, thus reducing latency.

[0007] In a first aspect, an embodiment of the present application provides a passive optical network system, comprising an optical distribution network (ODN), a first optical network unit (ONU), and a second ONU; the first ONU is provided with a first transmitter for transmitting a first signal of a preset wavelength to the ODN; the backbone optical fiber of the ODN is equipped with an optical reflector for optically reflecting the signal of the preset wavelength, for reflecting the first signal so that the first signal is transmitted to the second ONU; and the second ONU is provided with a first receiver for receiving the first signal. In this embodiment of the present application, an optical reflector installed in the ODN is used to optically reflect the first signal transmitted from the first ONU to the second ONU, so that the first signal can reach the second ONU without passing through the OLT, thereby achieving passive optical switching within a local area and enabling the first ONU to transmit data to the second ONU within the local area. Therefore, the solution of the embodiment of the present application does not require passing through the OLT, and thus has a low latency. Furthermore, since the OLT does not need to forward the first signal, the solution provided by the embodiment of the present application actually reduces the load on the OLT.

[0008] In conjunction with the first aspect, in one implementation of the embodiments of the present application, the second ONU is further provided with a second transmitter for transmitting a second signal of a preset wavelength to the ODN; the optical reflector is further provided with a second transmitter for reflecting the second signal so that the second signal is transmitted to the first ONU; and the first ONU is further provided with a second receiver for receiving the second signal. This implementation provides a method for the second ONU to transmit the second signal to the first ONU, making the solution provided by the embodiments of the present application more comprehensive.

[0009] In conjunction with the first aspect, in one implementation of the embodiments of the present application, the system further includes an optical line terminal (OLT); the first ONU is provided with a third transmitter for transmitting a third signal having a non-preset wavelength to the ODN; the optical reflector does not reflect the third signal, allowing the third signal to pass through the optical reflector and be transmitted to the OLT; and the first ONU is provided with a third receiver for receiving a fourth signal from the OLT that has passed through the optical reflector. This implementation provides a method for transmitting north-south traffic, making the solution provided by the embodiments of the present application more comprehensive.

[0010] In conjunction with the first aspect, in one implementation of the embodiments of the present application, a dynamic bandwidth scheduling (DBA) module is provided on the OLT; the DBA module is configured to receive a request from a first ONU and send an authorized allocated time slot to the first ONU; the first ONU transmits a first signal to the ODN via a first transmitter during the time slot allocated by the OLT. In this implementation, the OLT can use the DBA module to perform authorization control and time slot control over the process of the first ONU sending the first signal to the second ONU, enriching the implementation of the control plane and making the solution provided by the embodiments of the present application more comprehensive.

[0011] In conjunction with the first aspect, in one implementation of the embodiment of the present application, the first ONU further includes an optical time domain reflectometer (OTDR) module; the OTDR module is configured to transmit a pulsed optical signal for testing the optical fiber link to the ODN via the first transmitter; the optical reflector is further configured to reflect the pulsed optical signal so that the pulsed optical signal is transmitted to the second receiver of the first ONU; and the first ONU generates a reflected light intensity curve based on the pulsed optical signal received by the second receiver. In this implementation, the first ONU can also obtain a reflected light intensity curve using the OTDR module and the above process, and then perform fault diagnosis and location based on the reflected light intensity curve.

[0012] In conjunction with the first aspect, in one implementation of the embodiment of the present application, the first ONU further includes a circulator; a first end of the circulator is connected to the output of the first transmitter, a second end of the circulator is connected to the wavelength combiner / demultiplexer of the first ONU, and a third end of the circulator is connected to the input of the second receiver of the first ONU. In this implementation, the circulator can separate the first upstream signal from the second downstream signal, making the solution provided by the embodiment of the present application more comprehensive.

[0013] In a second aspect, embodiments of the present application provide an optical distribution network (ODN), wherein a backbone optical fiber of the optical distribution network (ODN) is equipped with an optical reflector that reflects a signal of a preset wavelength. The optical reflector is configured to reflect a first signal, the first signal being a signal of a preset wavelength from a first optical network unit (ONU), so that the first signal is transmitted to a second ONU. The second ONU is provided with a first receiver that receives the first signal. The optical reflector installed in the optical distribution network can implement the solutions of the embodiments of the present application. Furthermore, the optical reflector can be a fully transmitting device that fully transmits a specific wavelength.

[0014] In a third aspect, embodiments of the present application provide an optical network unit (ONU), comprising a first transmitter configured to transmit a first signal of a preset wavelength to an optical distribution network (ODN), such that an optical reflector mounted on a trunk optical fiber of the ODN reflects the first signal, thereby transmitting the first signal to another optical network unit (ONU); wherein the optical reflector is configured to optically reflect the signal of the preset wavelength, and the other ONU is provided with a first receiver configured to receive the first signal. The technical effects of the optical network unit of the third aspect of the present application can be understood with reference to the relevant effects of the first ONU described above in the first aspect, and are not further elaborated here.

[0015] In combination with the third aspect, in one implementation of an embodiment of the present application, the optical network unit also includes a second receiver for receiving a second signal; wherein the second signal is a signal of a preset wavelength sent by a second transmitter in another ONU, and the second signal is reflected by the optical reflecting device and then transmitted to the second receiver of the optical network unit.

[0016] In combination with the third aspect, in one implementation of an embodiment of the present application, the optical network unit further includes a third transmitter, which is used to send a third signal of a non-preset wavelength to the ODN, so that the optical reflecting device does not reflect the third signal, so that the third signal passes through the optical reflecting device and is transmitted to the optical line terminal OLT; the optical network unit further includes a third receiver, which is used to receive a fourth signal from the OLT that passes through the optical reflecting device.

[0017] In combination with the third aspect, in one implementation of an embodiment of the present application, the optical network unit also includes an optical time domain reflectometer OTDR module; the OTDR module is used to send a pulsed light signal for testing the optical fiber link to the ODN through a first transmitter, so that the optical reflecting device reflects the pulsed light signal, so that the pulsed light signal is transmitted to the second receiver of the optical network unit; the optical network unit is used to generate a reflected light intensity curve based on the pulsed light signal received by the second receiver.

[0018] In combination with the third aspect, in one implementation of the embodiment of the present application, the optical network unit also includes a circulator; the first end of the circulator is connected to the output end of the first transmitter, the second end of the circulator is connected to the wavelength combiner / demultiplexer of the optical network unit, and the third end of the circulator is connected to the input end of the second receiver of the optical network unit.

[0019] In a fourth aspect, an embodiment of the present application provides an optical line terminal, wherein the optical line terminal OLT is connected to multiple optical network units ONUs through an optical distribution network ODN, wherein the multiple optical network units ONUs include a first ONU and a second ONU, and the OLT includes: a first dynamic bandwidth scheduling DBA module, used to authorize the allocation of a first time slot period to the first ONU, so that the first ONU sends a first signal to the ODN through a first transmitter of the first ONU during the first time slot, the trunk optical fiber of the ODN is equipped with an optical reflecting device for optically reflecting a signal of a preset wavelength, which is used to reflect the first signal so that the first signal is transmitted to the second ONU, and the second ONU is provided with a first receiver for receiving the first signal; a second DBA module, used to authorize the allocation of a second time slot period to the first ONU, so that the first ONU sends a third signal to the ODN through a third transmitter of the first ONU during the second time slot, the third signal is a signal of a non-preset wavelength, the optical reflecting device does not reflect the third signal, so that the third signal passes through the optical reflecting device and is transmitted to the OLT; a transmitter, used to send the first time slot period and / or the second time slot period to the first ONU. The optical line terminal provided in this application can include two DBA modules: a first DBA module and a second DBA module. The first DBA module is used to control data transmission in the east-west direction, while the second DBA module is used to control data transmission in the north-south direction. Therefore, the optical line terminal can control data transmission through these two DBA modules, making the solutions provided in the embodiments of this application more comprehensive.

[0020] In combination with the fourth aspect, in an implementation method of an embodiment of the present application, the optical line terminal also includes: a receiver, used to receive a request from the first ONU, so that the first DBA module allocates the first time slot period to the first ONU according to the request or enables the second DBA module to allocate the second time slot period to the first ONU according to the request.

[0021] In the fifth aspect, an embodiment of the present application provides an optical network unit ONU, including: a media access control MAC chip, a transmitter and a receiver; the MAC chip, the transmitter and the receiver are interconnected through lines, and the MAC chip is used to realize the functions of the optical network unit as in the third aspect.

[0022] In a sixth aspect, an embodiment of the present application provides an optical line terminal OLT, comprising: a media access control MAC chip, a transmitter, and a receiver; the MAC chip, the transmitter, and the receiver are interconnected through a line, and the MAC chip is used to implement the functions of the optical line terminal as in the fourth aspect.

[0023] In the seventh aspect, an embodiment of the present application provides an optical line terminal OLT, comprising: a media access control MAC chip, a dynamic bandwidth scheduling DBA chip, a transmitter and a receiver; the MAC chip, the DBA chip, the transmitter and the receiver are interconnected through a line, and the DBA chip is used to implement the functions of the optical line terminal of the fourth aspect.

[0024] In an eighth aspect, an embodiment of the present application provides an optical line terminal (OLT), comprising: a processor, a memory, a transmitter, and a receiver; the processor, the memory, the transmitter, and the receiver are interconnected via a line, and the processor calls a program code in the memory so that the OLT implements the functions of the optical line terminal of the fourth aspect.

[0025] In a ninth aspect, an embodiment of the present application provides a passive optical network, which includes: an ONU as in the fifth aspect and an OLT as in the sixth aspect, the seventh aspect or the eighth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a PON architecture diagram provided by this application;

[0027] Figure 2 Schematic diagram of north-south flow and east-west flow;

[0028] Figure 3 A schematic diagram of a passive optical network system provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of an optical line terminal provided in an embodiment of the present application;

[0030] Figure 5 Schematic diagram of application scenarios provided by embodiments of the present application;

[0031] Figure 6 This is a schematic diagram of using the OTDR module for fault diagnosis;

[0032] Figure 7 A schematic diagram of another optical line terminal provided in an embodiment of the present application;

[0033] Figure 8 A schematic diagram of another optical line terminal provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The present invention provides a passive optical network system and related devices. The optical reflectors in the ODN reflect the signals sent from one ONU to another, thus achieving passive optical switching within a local area. The signals do not need to pass through the OLT, thus reducing latency.

[0035] The terms "first," "second," "third," "fourth," etc. (if any) in the specification and claims of the present application and in the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential sequence. It should be understood that the numbers used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "corresponding to," and any variations thereof, are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or apparatus.

[0036] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0037] Figure 3 A schematic diagram of a passive optical network system provided in an embodiment of the present application is provided. The system at least includes: an optical distribution network (ODN), a first optical network unit (ONU), and a second ONU.

[0038] The first ONU is provided with a first transmitter for transmitting a first signal of a preset wavelength to the ODN. The ODN's trunk optical fiber is equipped with an optical reflector for reflecting signals of the preset wavelength, thereby reflecting the first signal so that the first signal is transmitted to the second ONU. The second ONU is provided with a first receiver for receiving the first signal.

[0039] In the embodiment of the present application, the first signal is generally transmitted in the form of an optical signal. The first signal is transmitted from the first transmitter, reflected by the optical reflector of the ODN, and then broadcast to all ONUs corresponding to the ODN. Therefore, the second ONU can receive the first signal.

[0040] It will be understood that the preset wavelength of the first signal is pre-set by personnel based on the specific wavelength corresponding to the optical reflector installed in the ODN. When the wavelength of the first signal is the preset wavelength, upon reaching the optical reflector, it is reflected by the optical reflector to all ONUs corresponding to the ODN. Therefore, the second ONU can receive the first signal. When signals other than the preset wavelength reach the optical reflector, these signals can pass through the optical reflector. Therefore, any optical reflector capable of reflecting optical signals of a specific wavelength and transmitting optical signals of other wavelengths can implement the solution of the present application.

[0041] In an embodiment of the present application, the optical reflector may be a device that reflects optical signals within a certain wavelength range, and thus the preset wavelength of the first signal may be within this wavelength range. In practical applications, the optical reflector may also transmit optical signals within certain wavelength ranges and reflect optical signals within other wavelength ranges. In this case, the preset wavelength of the first signal may be set to the wavelength range corresponding to the reflection by the optical reflector. Therefore, the wavelength range corresponding to the optical signal reflected by the optical reflector matches the preset wavelength of the first signal. This matching relationship enables the optical reflector to reflect the first signal to implement the solution provided by the embodiment of the present application. The embodiment of the present application does not limit the wavelength range corresponding to the optical signal reflected by the optical reflector.

[0042] It is understood that the optical reflector can partially or completely reflect the first signal. When the optical reflector partially reflects the first signal, the solution of the embodiment of the present application is implemented as long as the second ONU can receive the first signal. When the optical reflector completely reflects the first signal, the solution of the embodiment of the present application is most effective.

[0043] In the embodiment of the present application, the optical reflector can be specifically set in the trunk optical fiber of the ODN, that is, the common end of the ODN, so that it can reflect the optical signal with a preset wavelength from any ONU, and after such optical signal is reflected, it can be broadcast to each ONU through the ODN. It is understood that the ODN includes trunk optical fiber and branch optical fiber, wherein the branch optical fiber is used to connect each ONU, and the optical signal can be transmitted to each ONU separately through the branch optical fiber. The trunk optical fiber is the main optical fiber that converges the optical signals of each ONU and is generally used for communication between the ONU and other devices (such as the OLT).

[0044] Specifically, the light reflecting device can be a filter wavelength division multiplexer (FWDM), a reflector that reflects a specific wavelength, an in-line total reflector, etc. The embodiment of the present application does not limit the specific model of the light reflecting device.

[0045] In an embodiment of the present application, each ONU connected to the ODN can receive the first signal, so the second ONU can receive the first signal. In some embodiments, the first receiver in the second ONU can convert the first signal into an electrical signal, recovering all the information carried by the optical carrier. A processing module configured in the second ONU can then extract relevant information from the total information and, based on this relevant information, determine that the first signal is intended for reception by the second ONU. The processing modules in the other ONUs can, based on this relevant information, determine that the first signal is not intended for reception and, therefore, discard the information about the first signal. The processing module configured in the ONU can be a Media Access Control (MAC) module, which is not limited in this embodiment of the present application. The relevant information recovered from the first signal can be the identifier of the target ONU, which matches the identifier of the second ONU but not the identifier of the other ONUs. Therefore, the processing module can determine whether the first signal is intended for reception based on the identifier of the target ONU. In actual applications, the ONUs may also use other methods to verify reception, which is not limited in this embodiment of the present application.

[0046] Therefore, in the solution provided in the embodiment of the present application, an optical reflector installed in the ODN is used to optically reflect the first signal sent by the first ONU to the second ONU. This allows the first signal to reach the second ONU without passing through the OLT, thus achieving passive optical switching within the local area and enabling the first ONU to transmit data to the second ONU within the local area. The solution provided in the embodiment of the present application does not require the OLT, so the solution has low latency. Furthermore, because the OLT does not need to forward the first signal, the solution provided in the embodiment of the present application actually reduces the load on the OLT.

[0047] In some embodiments, the optical reflector may be a total reflection device that totally reflects optical signals of a specific wavelength. Using a total reflection device to achieve reflection can achieve a better reflection effect, thereby reducing the loss of the first signal.

[0048] In some embodiments, the second ONU is further provided with a second transmitter for sending a second signal of a preset wavelength to the ODN; the optical reflecting device is further used to reflect the second signal so that the second signal is transmitted to the first ONU; the first ONU is further provided with a second receiver for receiving the second signal.

[0049] In an embodiment of the present application, the second ONU sends a second signal through a second transmitter, and the optical reflecting device corresponding to the ODN can reflect and broadcast the second signal to all ONUs communicating with the ODN, so that the first ONU receives the second signal through the second receiver, thereby enabling the second ONU to send data to the first ONU.

[0050] It is understandable that the wavelength of the first signal and the wavelength of the second signal may be the same, both corresponding to the wavelength of the light reflected by the optical reflector. Therefore, the optical reflector corresponding to the ODN may reflect both the first signal and the second signal.

[0051] Combined with the transmission of the above-mentioned first signal, the embodiment of the present application can actually realize bidirectional data transmission between the first ONU and the second ONU within the local area, realize data communication between the first ONU and the second ONU, and realize east-west transmission of data within the local area.

[0052] In some embodiments, Figure 3 The system shown also includes an optical line terminal (OLT); a third transmitter is provided in the first ONU, for sending a third signal of a non-preset wavelength to the ODN; the optical reflector does not reflect the third signal, so that the third signal passes through the optical reflector and is transmitted to the OLT; the first ONU is provided with a third receiver, for receiving a fourth signal from the OLT that passes through the optical reflector.

[0053] In an embodiment of the present application, the wavelength of the third signal is different from that of the first signal, and the optical reflector does not reflect the third signal, but instead allows the third signal to pass through the optical reflector. Therefore, after the third signal is emitted from the third transmitter of the first ONU, it can pass through the ODN and the optical reflector to reach the OLT, achieving north-south data transmission from the first ONU to the OLT. Similarly, the fourth signal passes through the OLT, the optical reflector, and the ODN, and is broadcast to all ONUs connected to the ODN. The first ONU can then receive the broadcasted fourth signal through the third receiver, achieving north-south data transmission from the OLT to the first ONU. Similarly, a fourth transmitter can also be provided in the second ONU to send optical signals to the OLT, and a fourth receiver can be provided to receive optical signals from the OLT.

[0054] Therefore, the solution of the embodiment of the present application can be compatible with the existing north-south traffic and realize the east-west traffic within the local area.

[0055] In some embodiments, a first dynamically bandwidth assignment (DBA) module is provided on the OLT; the first DBA module is used to receive a request from a first ONU and send an authorized allocated time slot to the first ONU; the first ONU sends a first signal to the ODN via a first transmitter during the time slot allocated by the OLT.

[0056] In the embodiment of the present application, the control plane is implemented by the OLT. Specifically, for east-west traffic, the OLT authorizes the first ONU to allocate a first time slot through the first DBA module, so that the first ONU sends a first signal to the ODN through the first transmitter during the first time slot allocated by the OLT, completing the east-west transmission of data.

[0057] In practical applications, the OLT is used not only to schedule east-west traffic, but also north-south traffic. A second DBA module is provided in the OLT. The second DBA module is configured to authorize the allocation of a second time slot to the first ONU, so that the first ONU transmits a third signal to the ODN via the first ONU's third transmitter during the second time slot. The third signal is a signal of a non-preset wavelength (the third signal is an optical signal with a different wavelength from the first signal), and the optical reflector does not reflect the third signal, allowing the third signal to pass through the optical reflector and be transmitted to the OLT.

[0058] It is understandable that the first time slot period and the second time slot period authorized by the OLT have no relationship and can overlap because optical signals of different wavelengths can propagate simultaneously. Taking the first time slot period as an example, the following describes the function of the first time slot period:

[0059] After receiving requests from each ONU for east-west transmission, the first DBA module allocates different first time slots to each ONU, allowing each ONU to transmit an east-west optical signal (first signal) during different time periods. This prevents conflicts between the ONUs in the east-west direction. For example, the first DBA module may allocate a one-minute time slot from 00:00 to 00:01 to the first ONU, allowing the first ONU to transmit the first signal during this time slot. Other ONUs are prohibited from transmitting east-west optical signals during this time slot (because the first DBA module has not authorized these ONUs to allocate time slots). Therefore, the first signal transmitted by the first ONU will not be interfered with by signals from other ONUs.

[0060] Similarly, after receiving the north-south transmission request from each ONU, the second DBA module allocates different second time slots to each ONU, so that each ONU sends the north-south transmission optical signal in different time periods, so there will be no conflict in the north-south traffic of the ONU.

[0061] In some embodiments, the first ONU further includes an optical time-domain reflectometer (OTDR) module; the OTDR module is used to send a pulsed light signal for testing the optical fiber link to the ODN; the optical reflector is also used to reflect the pulsed light signal so that the pulsed light signal is transmitted to the second receiver of the first ONU; the first ONU generates a reflected light intensity curve based on the pulsed light signal received by the second receiver.

[0062] In an embodiment of the present application, after the OTDR module sends a pulsed optical signal to the ODN, the backward Rayleigh scattered light of the pulsed optical signal during the optical fiber transmission process is continuously reflected back to the second receiver of the first ONU. The first ONU describes the intensity of the pulsed optical signal received by the second receiver as a reflected light intensity curve, thereby being able to describe the attenuation and reflection time on the optical fiber link between the ONU and the total reflector on the reflected light intensity curve. When a fiber link fails, the fault location can be determined by the reflected light intensity curve. The specific method for determining the fault location is similar to the method for determining the location of the optical fiber fault point using an optical time domain reflectometer and will not be repeated here. Therefore, in the solution provided in the embodiment of the present application, the location of the fault can be estimated by the OTDR module.

[0063] In some embodiments, the first ONU further includes a circulator (also referred to as a circulator); a first end of the circulator is connected to an output end of the first transmitter, a second end of the circulator is connected to a first multiplexer / demultiplexer of the first ONU, and a third end of the circulator is connected to an input end of a second receiver of the first ONU.

[0064] like Figure 3As shown, the circle above the first transmitter in the first ONU is a schematic diagram of a circulator. The circulator's circulation direction is specifically clockwise. Therefore, the optical signal transmitted by the first transmitter can be input from the first end of the circulator and output from the second end of the circulator to the first wavelength combiner / demultiplexer. The optical signal input from the first wavelength combiner / demultiplexer to the second end of the circulator passes through the circulator and is output from the third end of the circulator to the second receiver. In actual applications, a circulator with a counterclockwise circulation direction can also be used, and the positions of the first transmitter and the second receiver can be matched to the counterclockwise direction. The embodiment of the present application does not limit the circulation direction of the circulator.

[0065] Similarly, a suitable circulator can also be installed in the second ONU. The specific details of the circulator are similar to those of the first ONU, and will not be repeated here.

[0066] The following is a detailed description of multiplexer / demultiplexer (Mux / Demux):

[0067] In this embodiment of the present application, the first wavelength multiplexing / demultiplexing device of the first ONU is used to multiplex the optical signal from the ODN into several parts and forward them to each ONU, or to combine the optical signals from different transmitters at the same time and then forward them to the ODN. The optical signals from each transmitter are usually of different wavelengths, so these optical signals do not interfere with each other.

[0068] The second wavelength multiplexing / demultiplexing device in the second ONU is similar to the first wavelength multiplexing / demultiplexing device, and will not be described in detail herein.

[0069] In an embodiment of the present application, the optical distribution network (ODN) is not only used to forward the optical signal sent by the OLT to N ONUs with a splitting ratio of 1:N, but also used to reflect and broadcast the optical signal of a preset wavelength from a certain ONU through an optical reflector, so that N ONUs receive the optical signal of the preset wavelength, realizing east-west transmission of data.

[0070] In an embodiment of the present application, a first optical network unit (ONU) includes at least a first transmitter configured to transmit a first signal of a preset wavelength to an optical distribution network (ODN), so that an optical reflector mounted on a trunk optical fiber of the ODN reflects the first signal, thereby transmitting the first signal to another optical network unit (ONU). The optical reflector is configured to optically reflect the signal of the preset wavelength, and the other ONU is provided with a first receiver configured to receive the first signal.

[0071] Furthermore, the first ONU also includes a second receiver for receiving a second signal; wherein the second signal is a signal of a preset wavelength sent by a second transmitter in another ONU, and the second signal is reflected by the optical reflecting device and then transmitted to the second receiver of the optical network unit.

[0072] Furthermore, the first ONU also includes a third transmitter, which is used to send a third signal of a non-preset wavelength to the ODN, so that the optical reflecting device does not reflect the third signal, so that the third signal passes through the optical reflecting device and is transmitted to the optical line terminal OLT; the first ONU also includes a third receiver, which is used to receive a fourth signal from the OLT that passes through the optical reflecting device.

[0073] Furthermore, the first ONU also includes a circulator; the first end of the circulator is connected to the output end of the first transmitter, the second end of the circulator is connected to the wavelength combiner / demultiplexer of the optical network unit, and the third end of the circulator is connected to the input end of the second receiver of the optical network unit.

[0074] Furthermore, the first ONU further includes an optical time domain reflectometer OTDR module ( Figure 3 The OTDR module is used to send a pulsed optical signal for testing the optical fiber link to the ODN, so that the optical reflector reflects the pulsed optical signal, so that the pulsed optical signal is transmitted to the second receiver of the optical network unit; the optical network unit is used to generate a reflected light intensity curve according to the pulsed optical signal received by the second receiver.

[0075] In addition, the first ONU further includes a first wavelength multiplexing / demultiplexing device, which has been described in the above embodiment and will not be described in detail here. The second ONU has a similar structure to the first ONU and will not be described in detail here.

[0076] Figure 4 Schematic diagram of an optical line terminal provided in an embodiment of the present application. The optical line terminal OLT provided in an embodiment of the present application includes:

[0077] A first dynamic bandwidth scheduling (DBA) module is configured to authorize allocation of a first time slot to the first ONU, so that the first ONU transmits a first signal to the ODN via a first transmitter of the first ONU during the first time slot. A trunk optical fiber of the ODN is equipped with an optical reflector that reflects light of a signal of a preset wavelength, and is configured to reflect the first signal so that the first signal is transmitted to the second ONU. The second ONU is provided with a first receiver for receiving the first signal.

[0078] The second DBA module is configured to authorize allocation of the second time slot to the first ONU, so that the first ONU transmits a third signal to the ODN through a third transmitter of the first ONU during the second time slot, where the third signal is a signal of a non-preset wavelength, and the optical reflector does not reflect the third signal, so that the third signal passes through the optical reflector and is transmitted to the OLT;

[0079] The transmitter is configured to send the first time slot period and / or the second time slot period to the first ONU.

[0080] The receiver is configured to receive a request from the first ONU, so that the first DBA module allocates a first time slot to the first ONU according to the request or the second DBA module allocates a second time slot to the first ONU according to the request.

[0081] The first DBA module and the second DBA module may be submodules of a media access control (MAC) module. The MAC module in the OLT is primarily used to implement access control between external switches and internal transmitters and receivers, and is also used to authorize and control north-south and east-west data transmission through the first and second DBA modules.

[0082] It is understood that the hardware structure of the MAC module can be a MAC chip, which can perform the operations of the first and second DBA modules described above. That is, the MAC chip can automatically allocate respective granted time slots to north-south traffic and east-west traffic based on its internal logic circuitry, ensuring that there is no time conflict during the transmission of north-south traffic or east-west traffic.

[0083] The OLT provided in the embodiment of the present application further includes a wavelength combiner / demultiplexer, which is used to forward the optical signal transmitted by the transmitter or forward the input optical signal to the receiver.

[0084] In the embodiments of the present application, the transmitter and receiver described above may be provided separately, or the functions of the transmitter and receiver may be implemented by a single optical transceiver. The embodiments of the present application do not limit the specific forms of the transmitter and receiver. It is understood that the transmitter may specifically be an optical transmitter, and the receiver may specifically be an optical receiver.

[0085] Figure 5 This is a schematic diagram of an application scenario provided by an embodiment of the present application. This scenario includes a load balancing switch (LSW), an optical line terminal (OLT), an optical distribution network (ODN), and several optical network units (ONUs). The ODN's backbone optical fibers are equipped with optical reflectors for specific wavelengths.

[0086] LSW is a switch used to communicate with the OLT, as well as with other switches and other OLTs to achieve network interconnection.

[0087] In this application example, the OLT and the Figure 4 The OLTs in the corresponding embodiments are similar and will not be described again here.

[0088] In this application example, the ODN split ratio can be 1:32, which means that the ODN can connect to 32 ONUs. Figure 5 Only two ONUs (ONU1 and ONU32) are shown for example. Other ONUs can refer to Figure 5 A passive device for total reflection of λ3 is connected in series to the backbone fiber of the ODN. Figure 3 The ODNs in the corresponding embodiments are similar and will not be described again here.

[0089] The ONU includes a multiplexer / demultiplexer Mux / Demux, a burst transmitter BTx1, a receiver Rx1, a burst transmitter BTx2, a burst receiver BRx2, a circulator, a media access control module MAC1, and a media access control module MAC2. Figure 3 The first wavelength multiplexer / demultiplexer, the third transmitter, the third receiver, the first transmitter, the second receiver and the circulator in the corresponding embodiments are similar and will not be described in detail here.

[0090] In the embodiments of the present application, MAC1 and MAC2 can be implemented by two different MAC chips or a single MAC chip, which is not a limitation of the present embodiment. When a signal is transmitted from an ONU and is transferred to the MAC chip, the MAC chip can determine which transmitter to use based on the current signal type (north-south traffic or east-west traffic), thereby ensuring that the signal is delivered to the appropriate device as needed. Similarly, when the ONU receives a signal, the MAC chip can analyze the received signal to determine whether it meets the requirements. For example, if the signal received by the second receiver is generally east-west traffic, if the MAC chip interprets the signal as not of this type, the MAC chip may discard the signal. Alternatively, if a signal is transmitted from ONU1 to ONU32, and the MAC chip in ONU2 interprets the signal and determines that it is intended for ONU32, the MAC chip may discard the signal. In other words, the MAC chip can be used to implement the signal transmission and reception functions of the aforementioned ONUs. For details, please refer to the aforementioned embodiments and will not be further described here. It will be understood that the burst transmitter can operate in burst mode or normal mode. Burst mode occurs when a transmitter receives an unexpected command during normal data transmission. The transmitter then "intercepts" the command and sends it out, or pauses the normal data flow, sending the command and then resuming it. For more information, see Burst Mode in PON Systems.

[0091] It can be understood that the function of the circulator is to separate the upstream λ3 optical signal and the downstream λ3 optical signal, wherein the upstream λ3 optical signal from BTx2 is transmitted clockwise to the ONU Mux / Demux, and the downstream λ3 optical signal from the ONU Mux / Demux is transmitted clockwise to BRx2 for data reception and recovery.

[0092] The ONU also includes MAC1 and MAC2. MAC1's basic function is to control north-south data transmission, while MAC2's basic function is to control east-west data transmission.

[0093] In this application example, north-south data transmission between the ONU and OLT follows the same principles as current standard GPON and 10GPON systems. The ONU's upstream transmission, BTx1, is time-division multiplexed using staggered time slots, scheduled by the OLT MAC DBA1. East-west data transmission between ONUs within the same OLT PON is accomplished via λ3, scheduled by the OLT MAC DBA2. The following describes a detailed east-west data transmission process:

[0094] When ONU1 wants to send data to ONU32, ONU1 first sends a LAN send request message to the OLT through ONU MAC1 and BTx1 (transmitted to the OLT via an optical signal with a wavelength of λ1). After receiving the LAN send request message from ONU1, the OLT MAC allocates a time slot authorization for burst transmission on λ3 to ONU1 through the DBA2 module, and sends an indication message containing the time slot authorization to ONU1 through λ2. After receiving the λ3 burst transmission indication message from the OLT, ONU1 sends an optical signal with a wavelength of λ3 through BTx2 during the specified time slot to achieve data transmission. The λ3 upstream signal sent by ONU1 passes through the circulator, ONU1 Mux / Demux, 1:32 ODN, λ3 full reflector, 1:32 ODN, ONU32 Mux / Demux, and ONU 32 circulator and enters ONU32 BRx2, thereby receiving and recovering the optical signal with wavelength λ3 from ONU1.

[0095] Similarly, the process of ONU32 sending data to ONU1 is similar to the above process, and the process of transmitting signal data between other ONUs is also similar, which will not be repeated here.

[0096] As can be seen from the above embodiments and application examples, the solution provided by this application uses a device built into the ODN that fully reflects the LAN wavelength, combined with a specially designed ONT transceiver module, to simply and efficiently implement passive optical switching within the local area within the PON system architecture, with low latency. Furthermore, the passive optical local area network in this application's solution has a separate control plane and switching plane, with the control plane moved to the OLT, and optical switching is achieved through passive devices in the ODN.

[0097] Figure 6 This is a schematic diagram of using the OTDR module for fault diagnosis. Figure 5 As shown on the basis of ONU, Figure 6 The ONU shown is equipped with an OTDR module, which can be used for fault detection and location of branch optical fibers.

[0098] It can be understood that the OTDR module can, under the scheduling authorization of the OLT MAC DBA2, send a pulsed optical signal for testing the optical fiber link via BTx2 in the upstream direction. The Rayleigh scattered light of this pulsed optical signal during optical fiber transmission is continuously reflected back to the BRx2 receiver. BRx2 describes the intensity of the reflected optical signal as a reflected light intensity curve. This reflected light intensity curve can then be used to describe the attenuation and reflection time of the optical fiber link between the ONU and the total reflector. Therefore, fault detection and location can be performed based on the reflected light intensity curve. The specific process is similar to the description of the OTDR module in the above embodiment and will not be repeated here.

[0099] Figure 7 Schematic diagram of another optical line terminal provided in an embodiment of the present application. The optical line terminal 700 includes: a processor 701, a memory 702, a MAC chip 704, a transmitter 705, and a receiver 706; the processor 701, the memory 702, the MAC chip 704, the transmitter 705, and the receiver 706 are interconnected via a communication bus 703, and the processor 701 calls the program code in the memory 702 so that the OLT implements the following Figure 3 、 Figure 4 or Figure 5 Specifically, the processor calls the program code in the memory to send relevant instructions to the MAC chip, so that the MAC chip allocates respective authorized time slots to the north-south traffic and the east-west traffic according to the instructions, realizing Figure 4 The operations of the first DBA module and the second DBA module in each corresponding embodiment.

[0100] It is understandable that the optical line terminal 700 further includes a wavelength multiplexing / demultiplexing device 707, which is similar to the aforementioned Figure 4 The wavelength combiner / demultiplexer of the Zhongguang line terminal is similar and will not be described in detail here.

[0101] Figure 8 Schematic diagram of another optical line terminal provided in an embodiment of the present application. The optical line terminal 800 includes: a dynamic bandwidth scheduling DBA chip 801, a MAC chip 803, a transmitter 804, a receiver 805 and a wavelength multiplexing / demultiplexing filter 806. The DBA chip 801, the MAC chip 803, the transmitter 804 and the receiver 805 are interconnected via a communication bus 802. The DBA chip 801 can be used to perform Figure 4 The operations of the first DBA module and the second DBA module in each corresponding embodiment.

[0102] In some cases, the DBA chip 801 may be composed of a first DBA chip and a second DBA chip, wherein the first DBA chip may be used to execute Figure 4 The second DBA chip can be used to perform the operations of the first DBA module in each embodiment. Figure 4 The operation of the second DBA module in each corresponding embodiment. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0104] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0105] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0106] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0107] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A passive optical network system, characterized in that: It includes an optical distribution network ODN, a first optical network unit ONU and a second ONU; The first ONU is provided with a first transmitter, configured to send a first signal of a preset wavelength to the ODN; The ODN is equipped with an optical reflector for optically reflecting a signal of a preset wavelength, and is configured to reflect the first signal so that the first signal is transmitted to the second ONU; The second ONU is provided with a first receiver for receiving the first signal.

2. The system according to claim 1, wherein: The second ONU is further provided with a second transmitter for sending a second signal of a preset wavelength to the ODN; The optical reflecting device is further configured to reflect the second signal so that the second signal is transmitted to the first ONU; The first ONU is further provided with a second receiver for receiving the second signal.

3. The system according to claim 1, wherein: The system also includes an optical line terminal OLT; The first ONU is provided with a third transmitter, configured to send a third signal of a non-preset wavelength to the ODN; The optical reflecting device does not reflect the third signal, so that the third signal passes through the optical reflecting device and is transmitted to the OLT; The first ONU is provided with a third receiver, which is used to receive a fourth signal from the OLT that passes through the optical reflecting device.

4. The system according to claim 3, characterized in that The OLT is provided with a dynamic bandwidth scheduling DBA module; The DBA module is used to receive a request from the first ONU and send an authorized allocated time slot to the first ONU; The first ONU sends the first signal to the ODN through the first transmitter during the time slot allocated by the OLT.

5. The system according to claim 1, wherein: The first ONU also includes an optical time domain reflectometer OTDR module; The OTDR module is used to send a pulse optical signal for testing an optical fiber link to the ODN through the first transmitter; The optical reflecting device is further configured to reflect the pulsed optical signal so that the pulsed optical signal is transmitted to the second receiver of the first ONU; The first ONU generates a reflected light intensity curve according to the pulsed light signal received by the second receiver.

6. The system according to any one of claims 1 to 5, characterized in that: The first ONU further includes a circulator; The first end of the circulator is connected to the output end of the first transmitter, the second end of the circulator is connected to the wavelength combiner / demultiplexer of the first ONU, and the third end of the circulator is connected to the input end of the second receiver of the first ONU.

7. An optical distribution network, characterized in that: The optical distribution network ODN is equipped with an optical reflecting device for optically reflecting a signal of a preset wavelength, and is used to reflect a first signal, where the first signal is a signal of a preset wavelength from the first ONU, so that the first signal is transmitted to the second ONU; The second ONU is provided with a first receiver for receiving the first signal.

8. An optical network unit, characterized in that: The device comprises a first transmitter, configured to send a first signal of a preset wavelength to an optical distribution network (ODN), so that an optical reflector on the ODN reflects the first signal, so that the first signal is transmitted to another optical network unit (ONU); The optical reflector is used to reflect the signal of a preset wavelength, and the other ONU is provided with a first receiver for receiving the first signal.

9. The optical network unit according to claim 8, characterized in that Also included is a second receiver for receiving a second signal; The second signal is a signal of a preset wavelength sent by the second transmitter in the other ONU, and the second signal is reflected by the optical reflecting device and then transmitted to the second receiver of the optical network unit.

10. The optical network unit according to claim 8 or 9, characterized in that: The optical transmission device further includes a third transmitter, configured to transmit a third signal of a non-preset wavelength to the ODN, so that the optical reflection device does not reflect the third signal, and the third signal passes through the optical reflection device and is transmitted to the optical line terminal OLT; The optical network unit further includes a third receiver configured to receive a fourth signal from the OLT that passes through the optical reflecting device.

11. The optical network unit according to claim 8, characterized in that Also includes an optical time domain reflectometer OTDR module; The OTDR module is used to send a pulse optical signal for testing an optical fiber link to the ODN through the first transmitter, so that the optical reflector reflects the pulse optical signal, so that the pulse optical signal is transmitted to the second receiver of the optical network unit; The optical network unit is used to generate a reflected light intensity curve according to the pulsed light signal received by the second receiver.

12. The optical network unit according to claim 8, characterized in that Also included are circulators; The first end of the circulator is connected to the output end of the first transmitter, the second end of the circulator is connected to the wavelength combiner / demultiplexer of the optical network unit, and the third end of the circulator is connected to the input end of the second receiver of the optical network unit.

13. An optical line terminal, characterized in that: The optical line terminal OLT is connected to a plurality of optical network units ONU through an optical distribution network ODN, wherein the plurality of optical network units ONU include a first ONU and a second ONU, and the OLT includes: a first dynamic bandwidth scheduling (DBA) module, configured to authorize allocation of a first time slot to the first ONU, so that the first ONU transmits a first signal to the ODN via a first transmitter of the first ONU during the first time slot; the ODN is equipped with an optical reflector for reflecting signals of a preset wavelength, configured to reflect the first signal so that the first signal is transmitted to the second ONU; and the second ONU is provided with a first receiver for receiving the first signal; a second DBA module, configured to authorize allocation of a second time slot to the first ONU, so that the first ONU transmits a third signal to the ODN through a third transmitter of the first ONU during the second time slot, wherein the third signal is a signal of a non-preset wavelength, and the optical reflector does not reflect the third signal, so that the third signal passes through the optical reflector and is transmitted to the OLT; A transmitter is used to send the first time slot period and / or the second time slot period to the first ONU.

14. The optical line terminal according to claim 13, wherein: Also includes: The receiver is configured to receive a request from the first ONU, so that the first DBA module allocates a first time slot to the first ONU according to the request or the second DBA module allocates a second time slot to the first ONU according to the request.

15. An optical network unit (ONU), characterized in that: include: Media Access Control (MAC) chip, transmitter, and receiver; The MAC chip, the transmitter and the receiver are connected to each other via lines, and the MAC chip is used to implement the function of the optical network unit of any one of claims 8 to 12.

16. An optical line terminal OLT, characterized in that: include: Media Access Control (MAC) chip, transmitter, and receiver; The MAC chip, the transmitter, and the receiver are connected to each other via a line, and the MAC chip is used to implement the function of the optical line terminal of any one of claims 13 to 14.

17. An optical line terminal OLT, characterized in that: include: Media access control (MAC) chip, dynamic bandwidth scheduling (DBA) chip, transmitter, and receiver; The MAC chip, the DBA chip, the transmitter and the receiver are connected to each other via lines, and the DBA chip is used to implement the function of the optical line terminal of any one of claims 13 to 14.

18. An optical line terminal OLT, characterized in that: include: Processor, memory, transmitter, and receiver; The processor, the memory, the transmitter, and the receiver are interconnected via lines, and the processor calls the program code in the memory so that the OLT implements the function of the optical line terminal of any one of claims 13 to 14.

19. A passive optical network, characterized in that: The passive optical network comprises: the ONU according to claim 15 and the OLT according to any one of claims 16 to 18.

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