Optical distribution network, optical network system, splitter and method for identifying ports of a splitter - Patents.com

Abstract

To solve the problem in the prior art that compatibility with existing optical network termination devices is not supported when identifying a splitter port, an optical distribution network, an optical network system, a splitter, and a method for identifying a splitter port are provided. The optical distribution network includes a splitter, a first optical filter, and a first power changing assembly. The splitter includes at least two output ports, each corresponding to at least one first optical filter, and different output ports correspond to different first optical filters, and the different first optical filters pass or reject different center wavelengths of detected light. Each output port of each splitter in the Nth level splitter corresponds to a first power changing assembly, and the first power changing assembly is configured to change the power of the first service light based on the received first detected light. In this way, the splitter port connected to the optical network termination device can be determined based on the first power of the first service light, the second power of the power-changed first service light, and the center wavelength of the corresponding detected light.

Description

[Technical field]

[0001] This application claims priority to Chinese Patent Application No. 202011358792.1, entitled “OPTICAL DISTRIBUTION NETWORK, OPTICAL NETWORK SYSTEM, SPLITTER, AND METHOD FOR IDENTIFYING PORT OF SPLITTER,” filed with the State Intellectual Property Office of the People's Republic of China on November 27, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of optical communication technology, and in particular to an optical distribution network, an optical network system, a splitter, and a method for identifying ports of a splitter. [Background technology]

[0003] With the development of communication technology, passive optical network (PON) systems are increasingly widely used in optical communication technology. The PON system mainly includes an optical line terminal (OLT), multiple optical network terminals (ONTs), and an optical distribution network (ODN) that connects the OLT and the ONT. The OLT is a central office device of telecommunications and is located at the central office in the PON network. The ONT, also called the "optical modem", is the terminating unit of the PON network. The ODN can provide an optical signal transmission channel between the OLT and the ONT. The ODN does not contain any electronic components or electronic power sources. The ODN mainly includes passive components such as splitters and fibers, and does not need to include active electronic devices. The PON network can flexibly support various topology structures such as tree topology, star topology, and bus topology.

[0004] The PON network has characteristics such as wide coverage, a large number of branching optical paths, and passivity. After the ODN network is put into operation, the topology connection relationship of the ODN network cannot be determined intuitively because the ports of the splitters in the ODN network connected to the ONT are invisible, in other words, the PON cannot identify the output ports of the splitters connected to the ONT. In the prior art, in order to determine the topology connection relationship of the ODN network, an additional assembly needs to be added to the ONT, or the receiving optical path of the ONT needs to be changed. However, this is not compatible with the existing ONT. Summary of the Invention [Means for solving the problem]

[0005] The present application provides an optical distribution network, an optical network system, a splitter, and a method for identifying a port of a splitter connected to an ONT while supporting compatibility of existing ONTs.

[0006] According to a first aspect, the present application provides an optical distribution network. The optical distribution network may include N levels of splitters, M first optical filters, and K first power modifying assemblies, where N, M, and K are all positive integers. Each of the N levels of splitters includes at least one splitter, and each of the at least one splitter may include at least two output ports, and each of the at least two output ports corresponds to at least one first optical filter, and different output ports correspond to different first optical filters, and the center wavelengths of the detected light that the different first optical filters pass or do not pass are different. Each output port of each splitter in the Nth level splitter further corresponds to a first power modifying assembly, and the first power modifying assembly is configured to modify the power of the first service light from the optical line termination based on the received first detected light, and the Nth level splitter is one of the N levels of splitters configured to connect to an optical network termination, and N is a positive integer.

[0007] Based on this solution, the central wavelengths of the detection light that different first optical filters pass or do not pass are different. When both the detection light and the first service light are transmitted to the first power modifying assembly, the first power modifying assembly can modify the power of the first service light. When only the first service light is transmitted to the first power modifying assembly, the first power modifying assembly does not modify the power of the first service light, so that the central wavelength of the corresponding detection light can be determined based on the first power of the first service light and the second power of the power-modified first service light, the corresponding first optical filter can be determined based on the central wavelength of the detection light, and the port of the splitter connected to the optical network termination device can be further determined based on the determined first optical filter.

[0008] In a possible implementation, N is an integer greater than 1. Specifically, the optical distribution network includes two or more levels of splitters. A first optical filter corresponding to any output port of a Kth level splitter is different from a first optical filter corresponding to any output port of an Hth level splitter. The Kth level splitter and the Hth level splitter are any two of the N level splitters, and H and K are both positive integers.

[0009] Based on this solution, the output ports of different level splitters correspond to different first optical filters, and thus it can be determined which level splitter among the N level splitters is connected to the optical network termination device.

[0010] In a possible implementation, N is an integer greater than 1. Specifically, the optical distribution network includes two or more levels of splitters. An output port of each splitter in an Lth level splitter corresponds to a second power modifying assembly, the Lth level splitter being a splitter other than an Nth level splitter in the N level splitters, and L is a positive integer. The second power modifying assembly is configured to modify a power of the first service light from the optical line termination based on the received second detected light.

[0011] Further, optionally, the first optical filter corresponding to the output port of the Lth level splitter is the same as the first optical filter corresponding to the output port of the Nth level splitter.

[0012] Based on this solution, when the output ports of the splitters of different levels correspond to the same first optical filter, the output ports of the splitters connected to the optical network termination device can be distinguished based on the different powers generated for the first service light by the second power changing assembly corresponding to the splitter. This helps to save wavelength resources, so as to reduce the specification of the splitter (in other words, the specification of the splitters of different levels is the same).

[0013] The following shows an example of a possible implementation for connecting an output port, a power modifying assembly corresponding to the output port, and a first optical filter corresponding to the output port. The i-th output port is used as an example. The i-th output port is any one of at least two output ports of any splitter in the N-level splitter, and i is a positive integer.

[0014] Implementation form 1: The i-th output port, the first optical filter corresponding to the i-th output port, and the first power changing assembly corresponding to the i-th output port or the second power changing assembly corresponding to the i-th output port are integrated together in sequence.

[0015] This simplifies the manufacturing process of the optical distribution network by integrating the splitter, the first optical filter, and the gain assembly together.

[0016] Implementation form 2: A first optical filter corresponding to the i-th output port is integrated into the i-th output port, and a first power change assembly corresponding to the i-th output port or a second power change assembly corresponding to the i-th output port is connected in series with the integrated first optical filter corresponding to the i-th output port.

[0017] Implementation form 3: A first optical filter corresponding to the i-th output port is connected in series to the i-th output port, and a first power changing assembly corresponding to the i-th output port or a second power changing assembly corresponding to the i-th output port is connected in series to the first optical filter corresponding to the i-th output port.

[0018] In possible implementations, the first power changing assembly is a first gain assembly and the second power changing assembly is a second gain assembly, or the first power changing assembly is a first attenuation assembly and the second power changing assembly is a second attenuation assembly.

[0019] In a possible implementation, the first power modifying assembly further corresponds to a second optical filter configured to reflect the first detected light from the first power modifying assembly back to the first power modifying assembly.

[0020] Based on this solution, the power of the first service light is changed at least twice in the first power changing assembly, in this way, the difference between the power fluctuations of the first service light when the first service light is output from different output ports is increased, thereby helping to improve the accuracy of the identified port.

[0021] It may also be understood that one end of the first power modifying assembly is connected to the first optical filter, and the other end of the first power modifying assembly is connected to the second optical filter.

[0022] According to a second aspect, the present application provides an optical network system. The optical network system may include an optical network termination device and an optical distribution network in any one of the first aspect or possible implementation forms of the first aspect. The optical network termination device is configured to determine a first power of a first service light from the optical distribution network and a second power of a power-modified first service light, and the first power and the second power are used to determine an output port of a splitter connected to the optical network termination device.

[0023] In a possible implementation, the optical network system further includes an optical line termination, which is configured to receive the first power and the second power from the optical network termination, determine a power fluctuation based on the first power and the second power, determine a central wavelength of the detected light that the first optical filter passes or does not pass based on the power fluctuation and the central wavelength of the first detected light, and determine an output port of a splitter connected to the optical network termination based on the central wavelength of the detected light that the first optical filter passes or does not pass and a correspondence between the central wavelength and the output port of the splitter.

[0024] In a possible implementation, the optical network termination device is configured to determine a power fluctuation based on the first power and the second power, determine a central wavelength of the detected light that the first optical filter will pass or not pass based on the power fluctuation and the central wavelength of the first detected light, and determine an output port of a splitter connected to the optical network termination device based on the central wavelength of the detected light that the first optical filter will pass or not pass and a correspondence between the central wavelength and the output port of the splitter.

[0025] In possible implementations, the detection light source can be a tunable light source and / or a combination of an optical switch and a light source emitting at least one fixed wavelength, the optical switch being configured to control one of the light sources emitting at least one fixed wavelength to output the detection light, the central wavelength of the detection light output by the light source corresponding to the central wavelength that the first optical filter passes or does not pass.

[0026] In a possible implementation, N is an integer greater than 1, and specifically, the optical distribution network includes two or more levels of splitters. A first optical filter corresponding to any output port of a Kth level splitter is different from a first optical filter corresponding to any output port of an Hth level splitter. The Kth level splitter and the Hth level splitter are any two of the N level splitters, and H and K are both positive integers.

[0027] Based on this solution, the output ports of different level splitters correspond to different first optical filters, and thus it can be determined which level splitter among the N level splitters is connected to the optical network termination device.

[0028] In a possible implementation, N is an integer greater than 1, and specifically, the optical distribution network includes two or more levels of splitters. An output port of each splitter in an Lth level splitter corresponds to a second power modifying assembly, the Lth level splitter being a splitter other than the Nth level splitter in the N level splitters, and L is a positive integer. The second power modifying assembly is configured to modify a power of the first service light from the optical line termination based on the received second detected light.

[0029] Further, optionally, the first optical filter corresponding to the output port of the Lth level splitter is the same as the first optical filter corresponding to the output port of the Nth level splitter.

[0030] Based on this solution, when the output ports of splitters at different levels correspond to the same first optical filter, the output ports of the splitters connected to the optical network termination device can be distinguished based on the different powers generated for the first service light by the second power changing assembly corresponding to the splitter.

[0031] The following shows an example of a possible implementation for connecting an output port, a power modifying assembly corresponding to the output port, and a first optical filter corresponding to the output port. The i-th output port is used as an example. The i-th output port is any one of at least two output ports of any splitter in the N-level splitter, and i is a positive integer.

[0032] Implementation form 1: The i-th output port, the first optical filter corresponding to the i-th output port, and the first power changing assembly corresponding to the i-th output port or the second power changing assembly corresponding to the i-th output port are integrated together in sequence.

[0033] This simplifies the manufacturing process of the optical distribution network by integrating the splitter, the first optical filter, and the gain assembly together.

[0034] Implementation form 2: A first optical filter corresponding to the i-th output port is integrated into the i-th output port, and a first power change assembly corresponding to the i-th output port or a second power change assembly corresponding to the i-th output port is connected in series with the integrated first optical filter corresponding to the i-th output port.

[0035] Implementation form 3: A first optical filter corresponding to the i-th output port is connected in series to the i-th output port, and a first power changing assembly corresponding to the i-th output port or a second power changing assembly corresponding to the i-th output port is connected in series to the first optical filter corresponding to the i-th output port.

[0036] In possible implementations, the first power changing assembly is a first gain assembly and the second power changing assembly is a second gain assembly, or the first power changing assembly is a first attenuation assembly and the second power changing assembly is a second attenuation assembly.

[0037] In a possible implementation, the first power modifying assembly further corresponds to a second optical filter configured to reflect the first detected light from the first power modifying assembly back to the first power modifying assembly.

[0038] Based on this solution, the power of the first service light is changed at least twice in the first power changing assembly, in this way, the difference between the power fluctuations of the first service light when the first service light is output from different output ports is increased, thereby helping to improve the accuracy of the identified port.

[0039] It may also be understood that one end of the first power modifying assembly is connected to the first optical filter, and the other end of the first power modifying assembly is connected to the second optical filter.

[0040] According to a third aspect, the present application provides a splitter. The splitter may include at least two output ports and at least one first optical filter corresponding to each of the at least two output ports. Different output ports correspond to different first optical filters, and the central wavelengths of detection light that the different first optical filters pass or do not pass are different.

[0041] Further, optionally, the splitter includes a power modifying assembly, the power modifying assembly configured to modify a power of the first service light from the optical line termination based on the received first detected light.

[0042] In a possible implementation, the power modifying assembly is a gain assembly or an attenuation assembly.

[0043] According to a fourth aspect, the present application provides a method for identifying a port of a splitter, the method being applied to an optical network system. The optical network system includes an optical distribution network and an optical network termination device. The optical distribution network includes N levels of splitters, M first optical filters, and K first power modification assemblies, where N, M, and K are all positive integers. Each of the N levels of splitters includes at least one splitter, each of the at least one splitter includes at least two output ports, each of the at least two output ports corresponds to at least one first optical filter, different output ports correspond to different first optical filters, and the center wavelengths of the detected light that the different first optical filters pass or do not pass are different. Each output port of each splitter in the Nth level splitter further corresponds to a first power modification assembly, and the Nth level splitter is one of the N levels of splitters configured to connect to the optical network termination device. The method includes receiving a first service light and determining a first power of the first service light, receiving a power-altered first service light and determining a second power of the power-altered first service light, where the power-altered first service light is obtained by modifying the power of the first service light based on the received first detected light by a first power modifying assembly, The first power and the second power are used to determine an output port of a splitter connected to an optical network termination device.

[0044] In a possible implementation, the optical network termination device can determine a power fluctuation based on the second power and the first power, determine a central wavelength of the detected light that the first optical filter will pass or not pass based on the power fluctuation and the central wavelength of the first detected light, and determine an output port of the splitter connected to the optical network termination device based on the central wavelength of the detected light that the first optical filter will pass or not pass and a correspondence between the central wavelength and the output port of the splitter.

[0045] In another possible implementation, the optical network system may further include an optical line termination, which receives the first power and the second power from the optical network termination, determines a power fluctuation based on the first power and the second power, determines a central wavelength of the detected light that the first optical filter passes or does not pass based on the power fluctuation and the central wavelength of the first detected light, and determines an output port of the splitter connected to the optical network termination based on the central wavelength of the detected light that the first optical filter passes or does not pass and a correspondence between the central wavelength and the output port of the splitter.

[0046] According to a fifth aspect, the present application provides a method for identifying a port of a splitter. The method includes the steps of: an optical network termination receiving a first service light from an optical line termination and determining a first power of the first service light; and the optical network termination receiving a power-modified first service light from a first power modifying assembly and determining a second power of the power-modified first service light, the power-modified first service light being obtained by modifying the power of the first service light based on a first detected light received by the first power modifying assembly. The center wavelength of the first detected light is a center wavelength that a first optical filter corresponding to the first power modifying assembly passes, and the center wavelengths of the detected light that different first optical filters pass or do not pass are different. The first power and the second power are used to determine an output port of a splitter connected to the optical network termination.

[0047] In a possible implementation, the optical network termination device determines a power fluctuation based on the second power and the first power, the optical network termination device determines a central wavelength of the detected light that the first optical filter passes or does not pass based on the power fluctuation and the central wavelength of the first detected light, and the optical network termination device determines an output port of the splitter connected to the optical network termination device based on the central wavelength of the detected light that the first optical filter passes or does not pass and a correspondence between the central wavelength and the output port of the splitter.

[0048] In another possible implementation, the optical line terminal receives a first power and a second power from the optical network terminal, the optical line terminal determines a power fluctuation based on the first power and the second power, the optical line terminal determines a central wavelength of the detected light to be passed or not passed by the first optical filter based on the power fluctuation and the central wavelength of the first detected light, and the optical line terminal determines an output port of the splitter connected to the optical network terminal based on the central wavelength of the detected light to be passed or not passed by the first optical filter and a correspondence between the central wavelength and the output port of the splitter.

[0049] According to a sixth aspect, the present application provides a computer-readable storage medium. The computer-readable storage medium stores a computer program or instructions. When the computer program or instructions are executed by an optical network termination or an optical line termination, the optical network termination or the optical line termination is enabled to perform the method of the fourth aspect or any one of the possible implementation forms of the fourth aspect.

[0050] According to a seventh aspect, the present application provides a computer program product. The computer program product includes a computer program or instructions, which, when executed by an optical network termination or an optical line termination, enables the optical network termination or the optical line termination to perform the method of the first aspect or any one of the possible implementation forms of the first aspect.

[0051] For technical effects that can be achieved in any one of the second to seventh aspects, please refer to the description of the advantageous effects in the first aspect, and details will not be repeated here. [Brief description of the drawings]

[0052] [Figure 1] FIG. 2 is a simplified schematic diagram of energy levels of an erbium ion according to the present application. [Diagram 2] 1 is a schematic diagram of the architecture of a PON system according to the present application; [Diagram 3] FIG. 1 is a schematic diagram of an architecture of an optical distribution network according to the present application. [Figure 4] FIG. 2 is a schematic diagram of a splitter structure according to the present application. [Figure 5a] FIG. 2 is a schematic diagram of the corresponding relationship between the output ports of the splitter and the first optical filter according to the present application. [Figure 5b] FIG. 13 is a schematic diagram of another correspondence between the output ports of the splitter and the first optical filter according to the present application. [Figure 6a] FIG. 2 is a schematic diagram of the corresponding relationship between each output port of a two-level splitter and a first optical filter according to the present application. [Figure 6b] FIG. 2 is a schematic diagram of another correspondence between the output ports of each of the two-level splitters and the first optical filter according to the present application. [Figure 6c] FIG. 2 is a schematic diagram of another correspondence between the output ports of each of the two-level splitters and the first optical filter according to the present application. [Figure 6d] FIG. 2 is a schematic diagram of another correspondence between the output ports of each of the two-level splitters and the first optical filter according to the present application. [Figure 6e] FIG. 13 is a schematic diagram of yet another correspondence between the output ports of each of the two-level splitters and the first optical filter according to the present application. [Figure 7a] 2 is a schematic diagram of a method of connecting an output port of a splitter, a first optical filter, and a gain assembly according to the present application. [Figure 7b] FIG. 13 is a schematic diagram of another method of connecting an output port of a splitter, a first optical filter, and a gain assembly according to the present application. [Figure 7c] FIG. 13 is a schematic diagram of yet another method of connecting an output port of a splitter, a first optical filter, and a gain assembly according to the present application. [Figure 8] 1 is a schematic diagram of the architecture of an optical network system according to the present application; [Figure 9a] 1 is a schematic diagram of a structure of a combination optical switch and a light source emitting a fixed wavelength according to the present application. [Figure 9b] 2 is a schematic diagram of the structure of another combination of an optical switch and a light source emitting a fixed wavelength according to the present application. [Figure 10a] 1 is a schematic diagram of the architecture of a PON system according to the present application; [Figure 10b] 1 is a schematic diagram of the architecture of a PON system according to the present application; [Figure 10c] 1 is a schematic diagram of the architecture of a PON system according to the present application; [Figure 11] 2 is a schematic flow chart of a method for identifying an output port of a splitter according to the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0054] The following explains some terms in this application. Please note that these explanations are intended to facilitate the understanding of those skilled in the art, but do not constitute any limitation on the scope of protection claimed in this application.

[0055] 1. Stimulated Brillouin scattering (SBS) effect The SBS effect is a Raman effect. Due to the interaction between photons and molecules, the silicon dioxide lattice of the fiber generates light scattering when the incident light is too strong, forming a frequency-shifted scattered wave. Part of the energy of the incident light is transferred to the backscattered light. As a result, the incident light is dissipated on the fiber. This effect occurs because the incident power is so high that the electromagnetic telescopic effect generated by the light wave stimulates ultrasonic waves in the material, and the incident light is scattered under the influence of ultrasonic waves.

[0056] 2. First Optical Filter The first optical filter is a device used for wavelength selection. The first optical filter can select or filter a required wavelength from a plurality of wavelengths.

[0057] 3. Splitter A splitter is a passive component, sometimes called an optical splitter, and may be a junction component having multiple inputs and multiple outputs. In general, when a splitter splits a normal link, it splits the light into multiple links in a ratio according to the power. It should be understood that there is some attenuation in the power of the link where the optical split is performed.

[0058] 4. Optical Switch An optical switch is an optical path conversion component, an optical component with one or more arbitrary transmission ports. The function of an optical switch is to perform physical switching or logical operations on optical signals in an optical transmission path or an integrated optical path. The optical switch may be a conventional mechanical optical switch, a micromechanical optical switch, a thermal optical switch, a liquid crystal optical switch, an electro-optical switch, an acousto-optical switch, etc. The mechanical optical switch can move the fiber to directly couple the light to the output end, or use a prism or reflector to switch the optical path to directly transmit or reflect the light to the output end.

[0059] 5. Doped Fiber A doped fiber is a fiber doped with a specific element, for example, a rare-earth doped fiber. A rare-earth doped fiber is an optical fiber in which ions of rare-earth elements are added to a silica fiber. The rare-earth doped fiber can be configured to amplify received signal light of various wavelengths. Specifically, the gain corresponding to each wavelength of signal light can be obtained through design based on the intrinsic parameters of the rare-earth doped fiber. The doped rare earth can be erbium ions, thulium ions, neodymium ions, erbium ions, ytterbium ions, etc. This is not limited in the present application.

[0060] The gain generated for the input signal light varies depending on the concentration of the doping element, and also varies depending on the type of doping element, i.e., the gain of a doped fiber is related to parameters such as the type and concentration of the doping element.

[0061] 6.Wavelength division multiplexing (WDM) Wavelength division multiplexing is a technique that combines two or more different wavelengths of optical signals (carrying various information) at the transmitting end by using a multiplexer (also called a combiner) and couples the combined signal into the same fiber of an optical line for transmission. At the receiving end, the optical signals with various wavelengths are separated by using a demultiplexer (also called a beam splitter or demultiplexer) and then further processed by an optical receiver to restore the original signal. This technique of transmitting two or more different wavelengths of optical signals on the same fiber is called wavelength division multiplexing. Wavelength division multiplexers transmit optical signals based on wavelength division multiplexing technology.

[0062] 7. Planar lightwave circuit (PLC) In a planar lightwave circuit, the lightwave circuit is arranged in a plane.

[0063] The above describes some terms in this application, and the following describes the technical features in this application. Please note that these descriptions are intended to facilitate the understanding of those skilled in the art, but do not constitute any limitation on the scope of protection claimed in this application.

[0064] An erbium doped fiber (EDF) is used as an example to explain the principle of amplifying signal light (also referred to as generating gain for signal light) by an EDF.

[0065] The principle by which EDF amplifies the signal light is to convert the energy of the detection light (i.e., pump light) into the energy of the signal light. The erbium ion has three energy levels, namely the E1 energy level, the E2 energy level, and the E3 energy level. Figure 1 is a simplified schematic diagram of the energy levels of the erbium ion. The E1 energy level represents the ground state, which has the lowest energy and the largest amount of particles. The E2 energy level is a metastable state, which is an intermediate energy level, and is more active than the ground state and more stable than the excited state. The amount of particles in the metastable state is relatively stable and can be kept in a stable state for a period of time. The E3 energy level represents the excited state, which has the highest energy.

[0066] When a detection light source is added and the photon energy of the detection light is equal to the energy difference between the E3 / E2 energy level and the E1 energy level, the erbium ion absorbs the detection light and jumps from the ground state to the excited state, in other words, the E1 energy level jumps to the E3 / E2 energy level after the energy of the detection light is absorbed. In this case, the EDF enters a population inversion state. Because the excited state is unstable, the erbium ion quickly returns to the E2 energy level. When the energy of the input signal light is equal to the energy difference between the E2 energy level and the E1 energy level, the erbium ion in the E2 energy level jumps to the ground state, which can generate stimulated emission light and amplify the signal light.

[0067] Based on the above, FIG. 2 is a schematic diagram of the architecture of a PON system. An example is used in which the PON system is a PON system based on a tree network topology structure. The PON system may include an OLT, an ODN, and an ONT. The OLT is connected to each of the four ONTs through the ODN. In FIG. 2, an example is used in which the four ONTs are ONT 1, ONT 2, ONT 3, and ONT 4, respectively. The ODN includes a feeder fiber, a splitter, and a distribution fiber. In FIG. 2, for example, a one-level splitter is included, and the splitter at that level is a 1×4 splitter. The OLT is connected to the splitter through the feeder fiber, and the splitter is connected to each ONT through the distribution fiber.

[0068] It should be understood that the number of OLTs, ONTs, splitters, and ports in a PON system, as well as the number of ports included in a splitter, are all not limited in this application. Figure 2 is merely a schematic diagram.

[0069] It should be noted that the transmission direction in which an optical signal is transmitted from an OLT to an ONT is referred to as a downstream direction. The transmission direction in which an optical signal is transmitted from an ONT to an OLT is referred to as an upstream direction. The OLT can transmit an optical signal to an ONT in a broadcast mode, and the ONT can transmit an optical signal to an OLT in a unicast mode. It should be understood that in the upstream direction, the PON system is a multi-point to point (MP2P) system, and in the downstream direction, the PON system is a point 2 multiple point (P2MP) system.

[0070] Based on the PON system shown in FIG. 2, in the prior art, the structure of the ONT needs to be modified to identify the output port of the splitter connected to the ONT. For example, a three-way optical subassembly is additionally added to the ONT, and the output port of the splitter connected to the ONT is determined by determining the power of the optical signal received by the three-way optical subassembly. In other words, in the prior art, when the port of the splitter connected to the ONT is determined, the structure of the existing ONT needs to be modified. In other words, the compatibility of the existing ONT is not supported.

[0071] In view of the above problems, the present application provides an optical distribution network, an optical network system, a splitter, and a method for identifying a port of a splitter. The output port of a splitter connected to an optical network termination device can be identified while supporting the compatibility of existing optical network termination devices. The following describes in detail the optical distribution network, the optical network system, the splitter, and the method for identifying a port of a splitter provided in the present application.

[0072] 3 is a schematic diagram of an architecture of an optical distribution network according to the present application. The optical distribution network includes N level splitters, M first optical filters, and K first power modifying assemblies, where N, M, and K are all positive integers. Each of the N level splitters includes at least one splitter, where each of the at least two output ports corresponds to at least one first optical filter, where different output ports correspond to different first optical filters, and the center wavelengths of the detected light that the different first optical filters pass or do not pass are different. Each output port of each splitter in the Nth level splitter further corresponds to a first power modifying assembly, where the first power modifying assembly is configured to modify the power of the first service light from the optical line termination based on the received first detected light, where the Nth level splitter is one of the N level splitters configured to connect to the optical network termination, where N is a positive integer.

[0073] In Fig. 3, an Nth level splitter is used as an example. For example, the Nth level splitter includes one splitter, the splitter includes eight output ports, and port #1 to port #8 are used to identify eight different output ports, and each output port corresponds to one first optical filter. Port #1 corresponds to the first optical filter 1 and corresponds to the power modifying assembly 1, port #2 corresponds to the first optical filter 2 and corresponds to the power modifying assembly 2, ..., port #8 corresponds to the first optical filter 8 and corresponds to the power modifying assembly 8. The central wavelengths of the detection light that the first optical filter 1 to the first optical filter 8 pass or do not pass are different, and the power modifying assembly 1 to the power modifying assembly 8 are collectively referred to as the first power modifying assembly.

[0074] It should be understood that the optical distribution network shown in Figure 3 is merely an example, and the optical distribution network in this application may have more or fewer splitters than the optical distribution network shown in Figure 3, or may have more or fewer output ports than the splitters shown in Figure 3.

[0075] Based on this solution, the central wavelengths of the detection light that different first optical filters pass or do not pass are different. When both the detection light and the first service light are transmitted to the first power modifying assembly, the first power modifying assembly can modify the power of the first service light. When only the first service light is transmitted to the first power modifying assembly, the first power modifying assembly does not modify the power of the first service light, so that the central wavelength of the corresponding detection light can be determined based on the first power of the first service light and the second power of the power-modified first service light, the corresponding first optical filter can be determined based on the central wavelength of the detection light, and the port of the splitter connected to the optical network termination device can be further determined based on the determined first optical filter.

[0076] In a possible implementation, the first service light includes, but is not limited to, downstream signal light of gigabit-capable passive optical networks (GPON) or Xgigabit-capable passive optical networks (XGPON), for example, 10 GPON or 20 GPON, where the wavelength of GPON is about 1490±10 nm and the wavelength of XGPON is about 1575 nm to 1581 nm.

[0077] In a possible implementation, the central wavelengths of the different detection lights are different, and the central wavelength of the first detection light can enable the particles in the first power changing assembly to jump from the ground state to the excited state. With reference to FIG. 1, when the first power changing assembly is an EDF, the central wavelength of the first detection light can pass through the corresponding first optical filter, and the erbium ions can be enabled to jump from the ground state (E1 energy level) to the excited state (e.g., E2 energy level or higher energy level). For the central wavelength of the detection light, please refer to the following related description of the detection light source.

[0078] In the following, each functional structure shown in FIG. 3 will be described to provide an example of a specific implementation solution.

[0079] 1. Optical Filter In a possible implementation, the first optical filter may be a bandstop filter (BSF). A bandstop filter is a filter that attenuates waves of a specific frequency band very low and passes light of a frequency band other than the specific frequency band. That is, a bandstop filter does not transmit light of a specific frequency band and transmits light of a frequency band other than the specific frequency band. The wavelength corresponding to the specific frequency band is the center wavelength of light that the bandstop filter does not pass. In other words, a bandstop filter does not pass light of a specific wavelength (i.e., center wavelength).

[0080] In another possible implementation, the first optical filter may alternatively be a band pass filter (BPF). A band pass filter is a filter that passes light in a specific frequency band and blocks (or attenuates to a very low level) light in other frequency bands. The wavelength corresponding to a specific frequency band is the center wavelength of light that the band pass filter passes. That is, the band pass filter passes light of a specific wavelength (i.e., center wavelength). It should be understood that a band stop filter is related to a band pass filter.

[0081] For example, the first optical filter may be a fiber filter. A fiber filter is a component that uses a special fiber structure to select or filter a wave with a central wavelength (i.e., a specific wavelength) from waves with different wavelengths. That is, the fiber filter may be a band-stop filter or a band-pass filter. The fiber filter may be, for example, a fiber bragg grating (FBG) or a long period fiber grating (LPG).

[0082] To facilitate the explanation of the solution, the central wavelength of the light that the first optical filter passes or does not pass is hereinafter referred to as the central wavelength corresponding to the first optical filter. The central wavelength corresponding to the first optical filter may also be understood to be the central wavelength of the light that the first optical filter passes or does not pass. That is, the central wavelength corresponding to the first optical filter in the following explanation may be replaced with the central wavelength of the light that the first optical filter transmits, or may be replaced with the central wavelength of the light that the first optical filter does not transmit.

[0083] In the present application, different first optical filters correspond to different central wavelengths. For example, the first optical filter 1 corresponds to a central wavelength λ1, the first optical filter 2 corresponds to a central wavelength λ2, and the first optical filter 3 corresponds to a central wavelength λ3. The central wavelengths λ1, λ2, and λ3 are different from each other. The first optical filter 1 corresponds to the central wavelength λ1 means that the first optical filter 1 transmits light of the central wavelength λ1, the first optical filter 2 corresponds to the central wavelength λ2 means that the first optical filter 2 transmits light of the central wavelength λ2, and the first optical filter 3 corresponds to the central wavelength λ3 means that the first optical filter 3 transmits light of the central wavelength λ3. Alternatively, the first optical filter 1 corresponding to a central wavelength λ1 means that the first optical filter 1 does not pass light of the central wavelength λ1, the first optical filter 2 corresponding to a central wavelength λ2 means that the first optical filter 2 does not pass light of the central wavelength λ2, and the first optical filter 3 corresponding to a central wavelength λ3 means that the first optical filter 3 does not pass light of the central wavelength λ3.

[0084] In a possible implementation, the second optical filter is a reflective optical filter. The second optical filter can reflect the entire band of light. In addition, optionally, the second optical filter can reflect the detection light of all center wavelengths emitted by the detection light source. For example, if the center wavelengths of the detection light emitted by the detection light source are respectively center wavelength λ1 to center wavelength λ8, the second optical filter can reflect all detection light of center wavelength λ1 to center wavelength λ8. It should be understood that different first power modification assemblies can correspond to the same second optical filter.

[0085] 2. Splitter In possible implementations, there are mainly two types of splitters: fused biconical taper type and planar lightwave circuit PLC type. Usually, 1×2 splitters and 1×4 splitters use fused biconical taper type. 1×8 and above splitters use PLC type. PLC type splitters use semiconductor processing technology, which ensures good light splitting consistency and good channel uniformity. 1×2 splitter indicates that the splitter contains one input port and two output ports, 1×4 splitter indicates that the splitter contains one input port and four output ports, and 1×8 splitter indicates that the splitter contains one input port and eight output ports.

[0086] FIG. 4 is a schematic diagram of the structure of a splitter according to the present application. It is used as an example for explanation that the splitter is a 1×8 splitter. Specifically, the splitter includes one input port and eight output ports. A signal light (e.g., a first service light) may be input to the splitter from the input port and split into eight parts, which are output from eight different output ports respectively (i.e., split into eight links). Note that the signal light may be equally divided into eight parts based on the power, or may be equally divided into eight parts based on a fixed ratio of power. It should be understood that the split ratio of the splitter may be equal or unequal. This is not limited in the present application.

[0087] 3. Power Modification Assembly In possible implementations, the power modifying assembly may be a gain assembly, which is an assembly that generates gain for the transmitted signal light, and an attenuation assembly, which is an assembly that attenuates the transmitted signal light.

[0088] For example, the power modifying assembly may be a doped fiber, such as EDF or thulium doped fiber (TDF), and may have a length, for example, of about 40 cm. Alternatively, the power modifying assembly may be a doped glass block, such as an erbium doped glass block or a thulium doped glass block. It should be noted that the power modifying assembly may alternatively be a fiber or glass block doped with another element, and the aforementioned rare earths are used merely as examples.

[0089] In this application, different power modifying assemblies generate different power variations for the first service light. Each output port of each splitter in the Nth level splitter corresponds to a first power modifying assembly, and different output ports may correspond to the same first power modifying assembly or different first power modifying assemblies.

[0090] In the following description, an example in which the power modifying assembly is a gain assembly is used to facilitate the description of the solution.

[0091] In a possible implementation, the first gain assembly generates a gain for the first service light based on the received first detected light. In other words, if both the first detected light and the first service light are transmitted to the gain assembly, the gain assembly can amplify the first service light. If only the first service light is transmitted to the gain assembly, the gain assembly may not generate a gain for the first service light and transmit the first service light to an output port of a next level splitter or optical network termination device.

[0092] In the following, the corresponding relationships between the output ports of the splitter, the first optical filter and the gain assembly are described by using different cases.

[0093] Case 1: One output port of the splitter corresponds to one first optical filter, and different output ports correspond to different first optical filters.

[0094] It can also be understood that the multiple output ports of the splitter have a one-to-one correspondence with the multiple first optical filters. In other words, the center wavelength corresponding to one first optical filter can identify one output port of the splitter. Figure 5a is a schematic diagram of the correspondence between the output ports and the first optical filters of the splitter according to the present application. A 1x8 splitter is used as an example. The splitter includes eight output ports, namely, output port 1 (port #1), output port 2 (port #2), output port 3 (port #3), output port 4 (port #4), output port 5 (port #5), output port 6 (port #6), output port 7 (port #7), and output port 8 (port #8). Output port 1 corresponds to first optical filter 1, output port 2 corresponds to first optical filter 2, output port 3 corresponds to first optical filter 3, output port 4 corresponds to first optical filter 4, output port 5 corresponds to first optical filter 5, output port 6 corresponds to first optical filter 6, output port 7 corresponds to first optical filter 7, and output port 8 corresponds to first optical filter 8. The central wavelength corresponding to first optical filter 1 is λ1, the central wavelength corresponding to first optical filter 2 is λ2, the central wavelength corresponding to first optical filter 3 is λ3, the central wavelength corresponding to first optical filter 4 is λ4, the central wavelength corresponding to first optical filter 5 is λ5, the central wavelength corresponding to first optical filter 6 is λ6, the central wavelength corresponding to first optical filter 7 is λ7, and the central wavelength corresponding to first optical filter 8 is λ8. The central wavelength λ1, the central wavelength λ2, the central wavelength λ3, the central wavelength λ4, the central wavelength λ5, the central wavelength λ6, the central wavelength λ7, and the central wavelength λ8 are different from one another.

[0095] Case 2: Some output ports of the splitter correspond to one first optical filter, and some output ports correspond to multiple filters.

[0096] It can also be understood that some output ports of a splitter may be identified by using a center wavelength corresponding to one first optical filter, and some output ports may be identified by using center wavelengths respectively corresponding to multiple first optical filters. In other words, a combination code of center wavelengths respectively corresponding to multiple first optical filters can identify an output port of one splitter. Figure 5b is a schematic diagram of another correspondence between output ports and first optical filters of a splitter according to the present application. A 1x7 splitter is used as an example. The splitter has output port 1 (port #1), output port 2 (port #2), output port 3 (port #3), output port 4 (port #4), output port 5 (port #5), output port 6 (port #6), and output port 7 (port #7). Output port 1 corresponds to the first optical filter 1, output port 2 corresponds to the first optical filter 2, output port 3 corresponds to the first optical filter 3, output port 4 corresponds to the first optical filter 1 and the first optical filter 2, output port 5 corresponds to the first optical filter 1 and the first optical filter 3, output port 6 corresponds to the first optical filter 2 and the first optical filter 3, and output port 7 corresponds to the first optical filter 1, the first optical filter 2 and the first optical filter 3. The central wavelength corresponding to the first optical filter 1 is λ1, the central wavelength corresponding to the first optical filter 2 is λ2, and the central wavelength corresponding to the first optical filter 3 is λ3. The central wavelength λ1, the central wavelength λ2, and the central wavelength λ3 are different from each other.That is, output port 1 may be identified using a central wavelength λ1 corresponding to the first optical filter 1, output port 2 may be identified using a central wavelength λ2 corresponding to the first optical filter 2, output port 3 may be identified using a central wavelength λ3 corresponding to the first optical filter 3, output port 4 may be identified using a combination of the central wavelength λ1 corresponding to the first optical filter 1 and the central wavelength λ2 corresponding to the first optical filter 2, output port 5 may be identified using a combination of the central wavelength λ1 corresponding to the first optical filter 1 and the central wavelength λ3 corresponding to the first optical filter 3, output port 6 may be identified using a combination of the central wavelength λ2 corresponding to the first optical filter 2 and the central wavelength λ3 corresponding to the first optical filter 3, and output port 7 may be identified using a combination of the central wavelength λ1 corresponding to the first optical filter 1, the central wavelength λ2 corresponding to the first optical filter 2, and the central wavelength λ3 corresponding to the first optical filter 3.

[0097] The different output ports of the splitter are identified by using combinations of center wavelengths corresponding to multiple first optical filters, which helps to reduce the amount of center wavelengths required.

[0098] It should be noted that the minimum number of different first optical filters required is determined based on the number of output ports of the splitter. For example, if the splitter includes eight output ports, at least three first optical filters corresponding to different center wavelengths are required for combining to distinguish the eight different output ports.

[0099] In the present application, different output ports of the same level splitter correspond to different first optical filters (which may be a single first optical filter (as shown in FIG. 5a) or may correspond to a combination of multiple first optical filters (as shown in FIG. 5b)), and the different first optical filters correspond to different center wavelengths. The output ports of the different level splitters may correspond to different first optical filters. For example, the first optical filter corresponding to any output port of the Kth level splitter is different from the first optical filter corresponding to any output port of the Hth level splitter, where H and K are both positive integers. The Kth level splitter and the Hth level splitter are any two of the N level splitters.

[0100] Alternatively, the output ports of the splitters of different levels may correspond to the same first optical filter. For example, the first optical filter corresponding to the output port of the Lth level splitter is the same as the first optical filter corresponding to the output port of the Nth level splitter, and the Lth level splitter is a splitter other than the Nth level splitter among the N level splitters, where L is a positive integer. It should be noted that the output port of the Lth level splitter further corresponds to a second power modifying assembly, and the second power modifying assembly is configured to modify the power of the first service light from the optical line termination based on the received second detected light.

[0101] In the following, the possible combination schemes of different levels of splitters are described separately. In order to facilitate the description of the solution, N=2 is used as an example. The two levels of splitters are respectively referred to as a first level splitter and a second level splitter. It should be understood that there may be multiple second level splitters. In the following description, in order to facilitate the description of the solution, an example in which there is one second level splitter is used.

[0102] Scheme 1: The first optical filter corresponding to the output port of the first-level splitter is different from the first optical filter corresponding to the output port of the second-level splitter.

[0103] FIG. 6a is a schematic diagram of the correspondence between the output ports and the first optical filters of each of the two-level splitters according to the present application. The eight output ports of the first level splitter correspond to eight different first optical filters, and the eight output ports of the second level splitter correspond to eight different first optical filters. The eight different first optical filters corresponding to the eight output ports of the first level splitter correspond to eight central wavelengths, namely, central wavelength λ1, central wavelength λ2, central wavelength λ3, central wavelength λ4, central wavelength λ5, central wavelength λ6, central wavelength λ7, and central wavelength λ8. The eight different first optical filters corresponding to the eight output ports of the second level splitter correspond to eight central wavelengths, namely, central wavelength λ9, central wavelength λ10, central wavelength λ11, central wavelength λ12, central wavelength λ13, central wavelength λ14, central wavelength λ15, and central wavelength λ16. The 16 central wavelengths from central wavelength λ1 to central wavelength λ16 are different from each other. For details, see Table 1.

[0104] [Table 1]

[0105] 6b is a schematic diagram of another correspondence between the output ports of each of the two-level splitters and the first optical filters according to the present application. The eight output ports of the first level splitter correspond to eight different first optical filters, and some of the eight output ports of the second level splitter can be identified by using a combination of center wavelengths corresponding to multiple first optical filters. The eight different first optical filters corresponding to the eight output ports of the first level splitter correspond to eight center wavelengths, namely, center wavelength λ1, center wavelength λ2, center wavelength λ3, center wavelength λ4, center wavelength λ5, center wavelength λ6, center wavelength λ7, and center wavelength λ8. Output port 1 of the second level splitter corresponds to the first optical filter 9, output port 2 of the second level splitter corresponds to the first optical filter 10, output port 3 of the second level splitter corresponds to the first optical filter 11, output port 4 of the second level splitter corresponds to the first optical filter 9 and the first optical filter 10, output port 5 of the second level splitter corresponds to the first optical filter 9 and the first optical filter 11, output port 6 of the second level splitter corresponds to the first optical filter 10 and the first optical filter 11, and output port 7 of the second level splitter corresponds to the first optical filter 9, the first optical filter 10, and the first optical filter 11. Please refer to Table 2 for details.

[0106] [Table 2]

[0107] According to scheme 1, the gain assembly can be arranged only on each output port of the last level splitter (i.e., the second level splitter). For example, the gain assembly may be arranged after the first optical filter connected to each output port of the second level splitter. In other words, the first optical filter and the gain assembly are sequentially integrated into each output port of the last level splitter. See Figure 6a or Figure 6b.

[0108] It should be noted that the gain assembly may alternatively be placed after the first optical filter connected to each output port of the splitter of each level. The gain assembly is placed only after the first optical filter connected to each output port of the last level splitter. This helps to simplify the process of the optical distribution network.

[0109] Scheme 2: The first optical filter corresponding to the output port of the first-level splitter is the same as the first optical filter corresponding to the output port of the second-level splitter.

[0110] 6c is a schematic diagram of another correspondence between the output ports of each of the two-level splitters and the first optical filters according to the present application. The eight output ports of the first level splitter correspond to eight different first optical filters, and the eight output ports of the second level splitter also correspond to eight different first optical filters. The eight different first optical filters corresponding to the eight output ports of the first level splitter correspond to eight center wavelengths, namely, center wavelength λ1, center wavelength λ2, center wavelength λ3, center wavelength λ4, center wavelength λ5, center wavelength λ6, center wavelength λ7, and center wavelength λ8. The eight different first optical filters corresponding to the eight output ports of the second level splitter correspond to eight center wavelengths, namely, center wavelength λ1, center wavelength λ2, center wavelength λ3, center wavelength λ4, center wavelength λ5, center wavelength λ6, center wavelength λ7, and center wavelength λ8. It can be understood that the eight first optical filters corresponding to the eight output ports of the splitter at the same level are different, and the eight first optical filters corresponding to the eight output ports of the splitter at the first level are the same as the eight first optical filters corresponding to the eight output ports of the splitter at the second level. For details, please refer to Table 3 below.

[0111] [Table 3]

[0112] 6d is a schematic diagram of another correspondence between the output ports of each of the two level splitters and the first optical filters according to the present application, where output port 1 of the first level splitter corresponds to the first optical filter 1, output port 2 of the first level splitter corresponds to the first optical filter 2, output port 3 of the first level splitter corresponds to the first optical filter 3, output port 4 of the first level splitter corresponds to the first optical filter 1 and the first optical filter 2, output port 5 of the first level splitter corresponds to the first optical filter 1 and the first optical filter 3, output port 6 of the first level splitter corresponds to the first optical filter 2 and the first optical filter 3, and output port 7 of the first level splitter corresponds to the first optical filter 1, the first optical filter 2, and the first optical filter 3. Output port 1 of the second level splitter corresponds to the first optical filter 1, output port 2 of the second level splitter corresponds to the first optical filter 2, output port 3 of the second level splitter corresponds to the first optical filter 3, output port 4 of the second level splitter corresponds to the first optical filter 1 and the first optical filter 2, output port 5 of the second level splitter corresponds to the first optical filter 1 and the first optical filter 3, output port 6 of the second level splitter corresponds to the first optical filter 2 and the first optical filter 3, and output port 7 of the second level splitter corresponds to the first optical filter 1, the first optical filter 2, and the first optical filter 3. Please refer to Table 4 for details.

[0113] [Table 4]

[0114] According to scheme 2, a gain assembly is disposed at the output port of the splitter of each level. For example, the gain assembly may be disposed after the first optical filter at each level. In other words, the first optical filter and the gain assembly are sequentially integrated at each output port of the splitter of each level. See Fig. 6c or Fig. 6d. For example, the first gain assembly is connected in series to the first optical filter connected to each output port of the splitter of the second level, and the second gain assembly is connected in series to the first optical filter connected to each output port of the splitter of the first level.

[0115] The above-mentioned scheme 2 is helpful to save wavelength resources, so as to further reduce the specification of the splitter (in other words, the specification of the first level splitter and the second level splitter are the same). In other words, the output port of the first level splitter and the output port of the second level splitter are identified by using the same wavelength.

[0116] Scheme 3: Some of the first optical filters corresponding to the output ports of the first-level splitter are the same as some of the first optical filters corresponding to the output ports of the second-level splitter.

[0117] 6e is a schematic diagram of yet another correspondence between the output ports of each of the two-level splitters and the first optical filters according to the present application. The eight output ports of the first level splitter correspond to eight different first optical filters. The eight different first optical filters corresponding to the eight output ports of the first level splitter correspond to eight center wavelengths, namely, center wavelength λ1, center wavelength λ2, center wavelength λ3, center wavelength λ4, center wavelength λ5, center wavelength λ6, center wavelength λ7, and center wavelength λ8. Output port 1 of the second level splitter corresponds to the first optical filter 4, output port 2 of the second level splitter corresponds to the first optical filter 2, output port 3 of the second level splitter corresponds to the first optical filter 3, output port 4 of the second level splitter corresponds to the first optical filter 2 and the first optical filter 4, output port 5 of the second level splitter corresponds to the first optical filter 3 and the first optical filter 4, output port 6 of the second level splitter corresponds to the first optical filter 3 and the first optical filter 2, and output port 7 of the second level splitter corresponds to the first optical filter 2, the first optical filter 3, and the first optical filter 4. Please refer to Table 5 for details.

[0118] [Table 5]

[0119] It should be noted that, alternatively, there may be another correspondence between the output ports of the second level splitters and the first optical filters, for example, output port 1 of the second level splitters corresponds to the first optical filter 3, output port 1 of the second level splitters corresponds to the first optical filter 4, output port 1 of the second level splitters corresponds to the first optical filter 2 and the first optical filter 3, output port 1 of the second level splitters corresponds to the first optical filter 3 and the first optical filter 4, or output port 1 of the second level splitters corresponds to the first optical filter 2, the first optical filter 3, and the first optical filter 4.

[0120] It is further noted that the three first optical filters connected to the output ports of the second level splitters can be any three of the seven first optical filters other than the first optical filter 1, and are not limited to the first optical filter 2 to the first optical filter 4. It can also be understood that the first optical filters connected to the output ports of the second level splitters cannot be the same as the first optical filters corresponding to the output ports of the splitters connected to the input ports of the second level splitters. For example, each output port of the second level splitter connected to the port #1 of the first level splitter cannot be connected to the first optical filter 1, each output port of the second level splitter connected to the port #2 of the first level splitter cannot be connected to the first optical filter 2, and so on.

[0121] According to scheme 3, a gain assembly is disposed at the output port of the splitter of each level. For example, the gain assembly may be disposed after the first optical filter at each level. In other words, the first optical filter and the gain assembly are sequentially integrated at each output port of the splitter of each level. See Fig. 6e. For example, the first gain assembly is connected in series to the first optical filter connected to each output port of the splitter of the second level, and the second gain assembly is connected in series to the first optical filter connected to each output port of the splitter of the first level.

[0122] It should be understood that the locations of the first level splitters and the second level splitters may alternatively be swapped.

[0123] Below are examples of three possible implementations for connecting the output ports of the splitter, the first optical filter, and the gain assembly.

[0124] Implementation 1: The output port of the splitter, the first optical filter, and the gain assembly are integrated together.

[0125] FIG. 7a is a schematic diagram of a scheme for connecting the output port of a splitter, a first optical filter, and a gain assembly according to the present application. The first optical filter and the gain assembly are sequentially integrated into the corresponding output port of the splitter, in other words, the output port of the first optical filter, the splitter, and the gain assembly are integrated together. As shown in FIG. 7a, the first optical filter 1 and the gain assembly are sequentially integrated into the output port 1 (port #1) of the splitter, the first optical filter 2 and the gain assembly are sequentially integrated into the output port 2 (port #2) of the splitter, ..., the first optical filter 8 and the gain assembly are sequentially integrated into the output port 8 (port #8) of the splitter. By integrating the splitter, the first optical filter, and the gain assembly together, the manufacturing process of the optical distribution network can be simplified.

[0126] Implementation 2: The output port of the splitter and the first optical filter are integrated and then connected in series to the gain assembly.

[0127] FIG. 7b is a schematic diagram of another method of connecting the output port of the splitter, the first optical filter, and the gain assembly according to the present application. The first optical filter may be integrated (e.g., etched or exposed to UV light) into the scattering fiber of the splitter and then serially connected (e.g., thermally melted) to the gain assembly. As shown in FIG. 7b, the first optical filter 1 is integrated into the output port 1 (port #1) of the splitter and then serially connected to the gain assembly, the first optical filter 2 is integrated into the output port 2 (port #2) of the splitter and then serially connected to the gain assembly, ..., the first optical filter 8 is integrated into the output port 8 (port #8) of the splitter and then serially connected to the gain assembly.

[0128] Implementation 3: A first optical filter is processed on the output port of the splitter and then connected in series to the gain assembly.

[0129] 7c is a schematic diagram of yet another method of connecting an output port of a splitter, a first optical filter, and a gain assembly according to the present application: The first optical filter is processed (e.g., etched or exposed to UV light) on the output port of the splitter and then connected in series to the gain assembly.

[0130] It should be noted that the gains generated by the gain assemblies corresponding to the output ports of the splitters in the above three implementations may be the same or different, which is not a limitation in this application.

[0131] According to the above-mentioned implementation form 1, the second optical filter may be integrated with the output port of the splitter, the first optical filter, and the gain assembly, or may be connected in series with the output port of the splitter, the first optical filter, and the gain assembly integrated together.

[0132] According to the above-mentioned implementations 2 and 3, the second optical filter may be connected in series with the gain assembly.

[0133] In a possible implementation, the splitter in the three implementations above may be a PLC type splitter.

[0134] In a possible implementation, the first power modifying assembly further corresponds to a second optical filter configured to reflect the first detected light from the first power modifying assembly back to the first power modifying assembly.

[0135] Referring to Figure 6a, one end of the first gain assembly is connected to the first optical filter, and the other end of the first gain assembly is connected to the second optical filter. The first gain assembly can amplify the power of the first service light by at least two times, which helps to improve the accuracy of the identified output port of the splitter connected to the optical network termination device.

[0136] Please note that one end of the first gain assembly in Figure 6b, Figure 6c, Figure 6d, or Figure 6e may alternatively be connected to a second optical filter. The above uses Figure 6a simply as an example. For the second optical filter, please refer to the related description above. Details will not be repeated here.

[0137] It is further noted that the present application does not limit the number of ports included in the splitters in the optical distribution network, the cascading manner of the splitters (e.g., single-level or multi-level), the splitting ratio of the splitters, etc. The above embodiments are merely examples to facilitate the description of the solution.

[0138] Based on the above-mentioned optical distribution network, FIG. 8 shows an optical network system according to the present application. The optical network system may include an optical network termination device and an optical distribution network in any one of the above-mentioned embodiments. For the optical distribution network, please refer to the description in any one of the above-mentioned embodiments. Details will not be repeated here. The optical network termination device is configured to determine a first power of a first service light from the optical distribution network and a second power of the power-modified first service light, and the first power and the second power are used to determine an output port of a splitter connected to the optical network termination device.

[0139] Further, optionally, the optical network system may include an optical line terminal. The optical line terminal is configured to emit a first service light. When the detection light source is not turned on, the first service light is transmitted to the optical network terminal through the optical distribution network, and the optical network terminal may be configured to determine a first power of the received first optical signal. When the detection light source is turned on, the detection light source is used to emit the detection light, and the detection light and the first service light may be coupled to the optical distribution network. In the optical distribution network, if the first optical filter passes the first detection light, both the first detection light and the first service light may be transmitted to the first power modifying assembly. The first power modifying assembly may be configured to modify the power of the first service light and transmit the power-modified first service light to the optical network terminal. If the first optical filter does not pass the first detection light, only the first service light may be transmitted to the first power modifying assembly. The first power modifying assembly does not modify the power of the first service light, and the first service light may be transmitted to the optical network termination device. It should be understood that when the first power modifying assembly receives only the first service light, the power of the first service light is not modified, and the first service light may be transmitted directly to the optical network termination device.

[0140] In a possible implementation, a photoelectric detector in the optical network termination device can determine a first power of the received first service light and a second power of the power-altered first service light.

[0141] Based on the optical network system shown in FIG. 8, the following shows two implementation examples of determining the ports of the splitter connected to the optical network termination device.

[0142] Implementation 1: The optical line terminal determines the port of the splitter connected to the optical network terminal.

[0143] In a possible implementation, the optical line termination device may be configured to receive a first power and a second power from the optical network termination device and determine an output port of a splitter connected to the optical network termination device based on the first power and the second power.

[0144] Further, optionally, the optical line termination device may be configured to receive the first power and the second power from the optical network termination device, determine a power fluctuation based on the second power and the first power, determine a central wavelength of the detected light to be passed or not passed by the first optical filter based on the power fluctuation and the central wavelength of the first detected light, and determine an output port of the splitter connected to the optical network termination device based on the central wavelength of the detected light to be passed or not passed by the first optical filter and a correspondence relationship (as shown in any one of Tables 1 to 5) between the central wavelength and the output port of the splitter.

[0145] For example, if the first optical filter is a band-stop filter and the power fluctuation is zero (in other words, the power remains unchanged), this indicates that the wavelength of the detection light that the first optical filter does not allow to pass is the central wavelength of the first detection light. If the first optical filter is a band-pass filter and the power changes, this indicates that the wavelength of the detection light that the first optical filter allows to pass is the central wavelength of the first detection light.

[0146] Implementation 2: The optical network terminator determines the port of the splitter connected to the optical network terminator.

[0147] In a possible implementation, the optical line termination may be configured to determine an output port of a splitter connected to the optical network termination based on the first power and the second power.

[0148] Further, optionally, the optical network termination may be configured to determine a power fluctuation based on the first power and the second power, determine a central wavelength of the detection light that the first optical filter passes or does not pass based on the power fluctuation and the central wavelength of the first detection light, and determine an output port of the splitter connected to the optical network termination based on the central wavelength of the detection light that the first optical filter passes or does not pass and the correspondence between the central wavelength and the output port of the splitter (as shown in any one of Tables 1 to 5). In this case, the optical network termination does not need to report the determined first power and second power to the optical line termination. It should be noted that the correspondence between the central wavelength and the output port of the splitter may alternatively be pre-stored in the optical network termination, or the optical line termination may send the correspondence between the central wavelength and the output port of the splitter (as shown in any one of Tables 1 to 5) to the optical network termination, and in response, the optical network termination receives the correspondence between the central wavelength and the output port of the splitter from the optical line termination.

[0149] In a possible implementation, the optical network system may further include a detection light source. Next, the detection light source will be described.

[0150] 4.Detection light source In a possible implementation, the minimum amount of wavelengths that can be emitted by the detection light source is the same as the amount of central wavelengths corresponding to the first optical filter in the optical distribution network.

[0151] Referring to FIG. 6a, the detection light source can emit detection light of at least 16 wavelengths, and the 16 central wavelengths of the detection light are respectively from central wavelength λ1 to central wavelength λ16. Referring to FIG. 6b, the detection light source can emit detection light of at least 11 wavelengths, and the 11 central wavelengths of the detection light are respectively from central wavelength λ1 to central wavelength λ11. Referring to FIG. 6c, the detection light source can emit detection light of at least 8 wavelengths, and the eight central wavelengths of the detection light are respectively from central wavelength λ1 to central wavelength λ8. Referring to FIG. 6d, the detection light source may emit detection light of at least three wavelengths, and the three central wavelengths of the detection light are respectively from central wavelength λ1 to central wavelength λ3. Referring to FIG. 6e, the detection light source can emit detection light of at least eight central wavelengths, and the eight central wavelengths of the detection light are respectively from central wavelength λ1 to central wavelength λ8. It should be understood that the detection light source may separately emit detection light of different central wavelengths. For example, the detection light source may emit detection light of one central wavelength at one instant in time.

[0152] Below are examples of two possible configurations of the detection light source.

[0153] Configuration 1: The detection light source can be a tunable light source.

[0154] A tunable light source means that the wavelength of the output detection light can be changed as needed. For example, the light source can be a tunable continuous wave (CW) light source or a tunable pulsed light source.

[0155] For example, the tunable light source may be a tunable laser, such as a distributed feedback (DFB) laser, a Fabry-Perot (FP) laser, or an electro-absorption modulated laser (EML). The following provides a detailed description separately.

[0156] DFB lasers mainly use semiconductor materials, including gallium antimonide (GaSb), gallium arsenide (GaAs), indium phosphate (InP), zinc sulfide (ZnS), etc., as dielectrics, and have a high side-mode suppression ratio (SMSR). SMSR, also called side-mode suppression ratio, is the ratio of the maximum intensity of the main mode to the maximum intensity of the side mode, and is an important indicator of longitudinal mode performance. A grating is integrated in the active layer of a DFB laser, in other words, the laser oscillation of a DFB laser is the optical coupling formed by the grating. By changing the magnitude of the current injected into the DFB laser, the wavelength of the light output by the DFB laser can be adjusted.

[0157] The principle by which an EML outputs a signal light is the same as that by which a DFB laser outputs a signal light. Specifically, the wavelength of the light output from the EML can be adjusted by changing the magnitude of the current injected into the EML.

[0158] The principle of outputting signal light by FP laser is to inject light into the optical resonant cavity of FP laser and make the lasing wavelength of the optical resonant cavity of FP laser coincide with the wavelength of the injected light, that is, by changing the wavelength of the injected light, the wavelength of the output light of FP laser is changed.

[0159] In a possible implementation, the light source may be controlled by using an optical line terminal such that the wavelength emitted by the light source is tunable.

[0160] Configuration 2: The detection light source can be a combination of an optical switch and a detection light source that emits at least one fixed wavelength.

[0161] The optical switch may be configured to control one detection light source in the at least one detection light source having a fixed wavelength to output the detection light. When a link of the optical switch is in a connected state, the detection light source corresponding to the link may output the detection light of the fixed wavelength. When a link of the optical switch is in a disconnected state, the detection light source corresponding to the link cannot output the detection light.

[0162] FIG. 9a is a schematic diagram of the structure of a combination of an optical switch and a detection light source emitting a fixed wavelength according to the present application. The optical switch may specifically be a 4×1 switch including four input ends and one output end. The four input ends of the optical switch are respectively connected to four detection light sources, and the output end of the optical switch is connected to the WDM. Specifically, the detection light source 1 is connected to the input end 1 of the optical switch, the detection light source 2 is connected to the input end 2 of the optical switch, the detection light source 3 is connected to the input end 3 of the optical switch, and the detection light source 4 is connected to the input end 4 of the optical switch. One detection light source may output one fixed wavelength detection light. Specifically, the detection light source 1 may output the detection light of wavelength 1, the detection light source 2 may output the detection light of wavelength 2, the detection light source 3 may output the detection light of wavelength 3, and the detection light source 4 may output the detection light of wavelength 4. When the input end 1 is connected to the output end, the link of the input end 1 is in a connected state, so that the detection light of wavelength 1 emitted by the detection light source 1 can be output to the WDM; when the input end 2 is connected to the output end, the link of the input end 2 is in a connected state, so that the detection light of wavelength 2 emitted by the detection light source 2 can be output to the WDM; and similarly in other cases.

[0163] 9b is a schematic diagram of the structure of another combination of an optical switch and a detection light source emitting a fixed wavelength according to the present application. The optical switch can specifically be a 4×4 switch including four input ends and four output ends. The four input ends are respectively connected to four detection light sources, and the four output ends are separately connected to the WMD. When the input end 1 is connected to the output end 1, the link of the input end 1 is in a connected state, so that the detection light of wavelength 1 emitted by the detection light source 1 can be output to the WDM, and when the input end 2 is connected to the output end 2, the link of the input end 2 is in a connected state, so that the detection light of wavelength 2 emitted by the detection light source 2 can be output to the WDM, and so on in other cases.

[0164] In addition, optionally, a low-frequency phase modulator or intensity modulator and radio frequency (RF) may be added to the output end of the detection light source to suppress the SBS effect. See FIG. 9a or FIG. 9b. The RF can input a modulation signal into the phase modulator or intensity modulator to modulate the phase or intensity of the detection light with a narrow linewidth emitted by the detection light source, so as to increase the linewidth of the detection light emitted by the detection light source, and further suppress the SBS effect. It should be understood that when the linewidth of the detection light is narrow and the power of the fiber is greater than 8 dBm, the SBS effect will occur in the fiber, specifically, most of the detection light will be dissipated throughout the fiber.

[0165] It should be noted that in Fig. 9a or 9b, the phase modulation or intensity modulation applied to the detection light belongs to external modulation. It should be understood that the phase or intensity modulation performed on the detection light may alternatively be internal modulation, specifically, the RF may input a modulation signal to the detection light source to implement the internal modulation performed on the phase or intensity of the detection light.

[0166] In a possible implementation, the detection light source can be a pump detection light source. The detection light source may select S-band, C-band, or U-band, and the wavelength range of the detection light can be selected based on the center wavelength of each first optical filter in the optical distribution network. The power of the detection light source can be adjusted over a wide range based on the existing network loss and erbium-doped fiber specifications.

[0167] Based on the foregoing, and with reference to a specific optical network system, the following provides an implementation process for identifying an output port of a splitter connected to an optical network termination device.

[0168] In the following description, for example, the optical network system is a PON system, the first optical filter is a band-stop filter, the manner of integrating the output port of the splitter, the first optical filter and the gain assembly is the above-mentioned implementation form 1, and the detection light source is a wavelength-tunable light source. An optical network termination device connected to the output port of the second-level splitter is used as an example.

[0169] It should be noted that when the wavelength of the detection light is the same as the central wavelength corresponding to the first optical filter, the detection light is reflected by the first optical filter to the input port, and the detection light cannot be continuously transmitted to the gain assembly, and only the first service light is transmitted to the gain assembly. In this case, the gain assembly does not generate gain for the first service light. When the wavelength of the detection light is different from the central wavelength corresponding to the first optical filter, both the detection light and the first service light can be transmitted to the gain assembly. In this case, under the action of the detection light, the gain assembly may generate gain for the first service light. In other words, the first service light may be amplified by the gain assembly, i.e., the power of the first service light is also changed. For the principle of amplifying the first service light by the gain assembly, please refer to the description of FIG. 1. Details will not be repeated here.

[0170] FIG. 10a is a schematic diagram of the architecture of a PON system according to the present application. The PON system may include a detection light source, a WDM, an OLT, an ODN, and an ONT. Two levels of splitters (a first level splitter and a second level splitter) are used as an example. For example, there is one second level splitter, and the ODN is the ODN shown in FIG. 6a (refer to the above related description, and the details are not described again here). The WDM may be configured to couple the received detection light and the first service light to a feeder fiber, and transmit the detection light and the first service light to the first level splitter through the feeder fiber. Each output port of the first level splitter may be configured to connect to one second level splitter, and each output port of the second level splitter may be configured to connect to one ONT.

[0171] When the detection light source is not turned on, the ONT is configured to receive the first service light from the OLT and determine a first power P0 of the first service light. It should be understood that when the first service light passes through the first gain assembly, the first gain assembly does not generate gain for the first service light. Further, the ONT is configured to report the first power P0 of the first service light to the OLT.

[0172] When the detection light source is turned on, it can be used to separately emit detection light of wavelengths λ1 to λ16 at different moments. In other words, at a certain moment, the detection light source may emit detection light of one central wavelength. For example, detection light of central wavelength λ1 is emitted at time t1, detection light of central wavelength λ2 is emitted at time t2, detection light of central wavelength λ3 is emitted at time t3, ..., detection light of central wavelength λ15 is emitted at time t15, and detection light of central wavelength λ16 is emitted at time t16.

[0173] When the central wavelength of the detected light is λ1, the ONT determines a second power P1 of the received power-altered first service light, when the central wavelength of the detected light is λ2, the ONT determines a second power P2 of the received power-altered first service light, ..., when the central wavelength of the detected light is λ15, the ONT determines a second power P15 of the received power-altered first service light, and when the central wavelength of the detected light is λ16, the ONT determines a second power P16 of the received power-altered first service light.

[0174] Further, optionally, the ONT is configured to report the determined second power to the OLT as shown in Table 6. In a possible implementation, the ONT can report one second power to the OLT every time the ONT determines a second power, or the ONT can report the 16 second powers together to the OLT after determining 16 second powers. In addition, the ONT can report the first power and the second power together to the OLT, or can report the first power first and then the second power. This is not limited in the present application.

[0175] [Table 6]

[0176] Correspondingly, the OLT is configured to receive second powers from the ONT, where the second powers are respectively a second power P1, a second power P2, a second power P3, a second power P4, a second power P5, a second power P6, a second power P7, a second power P8, a second power P9, a second power P10, a second power P11, a second power P12, a second power P13, a second power P14, a second power P15, and a second power P16, receive a first power P0 from the ONT, and separately calculate a power fluctuation ΔPn, where ΔPn=Pn-P0, where the value of n is in the range of 1 to 16.

[0177] Further, the OLT may be configured to determine an output port of the splitter connected to the ONT based on the power fluctuation ΔPn. In a possible implementation, the power fluctuation ΔPn may be compared with a resolution or decision threshold (Δm, which may be set to 0.3 dB, for example) of the PON system to determine whether the power of the signal light received by the OLT changes when the detection light source is turned on and when the detection light source is not turned on. If ΔPn ≧ Δm, ΔPn is recorded as "1", indicating that the power of the first service light changes by one unit under the detection light of the wavelength λn. This indicates that both the detection light of the wavelength λn and the first service light are incident on the first gain assembly, and further indicates that the first optical filter corresponding to the output port of the splitter passes the detection light of the wavelength λn. If ΔPn < Δm, ΔPn may be recorded as "0", indicating that the power of the first service light does not change under the detection light of the wavelength λn. This indicates that the detection light of wavelength λn and the first service light are not incident on the first gain assembly together, and the first optical filter corresponding to the output port of the splitter does not pass (or reflects) the detection light of wavelength λn. Furthermore, it may be determined that the center wavelength corresponding to the first optical filter is also λn. Therefore, the output port of the splitter connected to the ONT may be determined based on the correspondence (as shown in Table 1 above) between the output port and the center wavelength of the splitter.

[0178] Note that ΔPn may be greater than Δm, and ΔPn is recorded as "1." If ΔPn≦Δm, ΔPn is recorded as "0."

[0179] In a possible implementation, the OLT may determine an output port of a first-level splitter connected to the ONT based on ΔP1 to ΔP8, and may determine an output port of a second-level splitter connected to the ONT based on ΔP9 to ΔP16.

[0180] For example, ΔP1 to ΔP8 are 01111111, respectively. Specifically, when the central wavelength of the detection light is λ1, the power of the signal light received by the ONT does not change. When the central wavelength of the detection light is λ2, when the central wavelength of the detection light is λ3, when the central wavelength of the detection light is λ4, when the central wavelength of the detection light is λ5, when the central wavelength of the detection light is λ6, when the central wavelength of the detection light is λ7, or when the central wavelength of the detection light is λ8, the power of the signal light received by the ONT changes. When the central wavelength of the detection light is the same as the central wavelength corresponding to the first optical filter, the detection light is reflected to the input end by the first optical filter. Therefore, the power of the signal light received by the ONT does not change. Therefore, the OLT can determine that the center wavelength corresponding to the first optical filter connected to the ONT is λ1, and based on the correspondence between the center wavelengths and the output ports of the splitters (as shown in Table 1), can determine that the center wavelength λ1 corresponds to output port 1 (port #1) of the first level splitter, and can further determine that the ONT is connected to port #1 of the first level splitter.

[0181] Furthermore, when the central wavelength of the detection light is λ2, the central wavelength of the detection light is λ3, the central wavelength of the detection light is λ4, the central wavelength of the detection light is λ5, the central wavelength of the detection light is λ6, the central wavelength of the detection light is λ7, or the central wavelength of the detection light is λ8, both the detection light and the first service light reach the gain assembly. This indicates that each of the seven wavelengths of the detection light is different from the central wavelength corresponding to the first optical filter. Therefore, the power of the signal light received by the ONT changes. Therefore, the OLT can determine that the ONT is not connected to port #2, port #3, port #4, port #5, port #6, port #7, or port #8 of the first level splitter.

[0182] For example, ΔP9 to ΔP16 are 01111111, respectively. Specifically, when the central wavelength of the detection light is λ9, the power of the signal light received by the ONT does not change. When the central wavelength of the detection light is λ10, when the central wavelength of the detection light is λ11, when the central wavelength of the detection light is λ12, when the central wavelength of the detection light is λ13, when the central wavelength of the detection light is λ14, when the central wavelength of the detection light is λ15, or when the central wavelength of the detection light is λ16, the power of the signal light received by the ONT changes. Based on the same principle, the OLT can determine that the central wavelength corresponding to the first optical filter connected to the ONT is λ9, and based on the correspondence relationship (as shown in Table 1) between the central wavelength and the output port of the splitter, it can determine that the output port of the second level splitter corresponding to the central wavelength λ9 is port #1, and further determine that the ONT is connected to port #1 of the second level splitter.

[0183] Furthermore, when the central wavelength of the detection light is λ10, the central wavelength of the detection light is λ11, the central wavelength of the detection light is λ12, the central wavelength of the detection light is λ13, the central wavelength of the detection light is λ14, the central wavelength of the detection light is λ15, or the central wavelength of the detection light is λ16, both the detection light and the first service light reach the gain assembly. This indicates that each of the seven wavelengths of the detection light is different from the central wavelength corresponding to the first optical filter. Therefore, the power of the signal light received by the ONT changes. Therefore, the OLT can determine that the ONT is not connected to port #2, port #3, port #4, port #5, port #6, port #7, and port #8 of the second level splitter.

[0184] Based on the foregoing, when the OLT determines that the power variations ΔP1 to ΔP16 are 0111111101111111, the OLT can further determine that the ONT is connected to port #1 of the first level splitter and port #1 of the second level splitter.

[0185] FIG. 10b is a schematic diagram of another PON system architecture according to the present application. The PON system may include a detection light source, a WDM, an OLT, an ODN, and an ONT. Two levels of splitters (i.e., a first level splitter and a second level splitter) are used as an example. For example, there is one second level splitter, and the ODN is the ODN shown in FIG. 6c (please refer to the related description above, and the details will not be described again here). The WDM may be configured to couple the received detection light and the first service light to a feeder fiber, and transmit the detection light and the first service light to the first level splitter through the feeder fiber. Each output port of the first level splitter may be configured to connect to one second level splitter, and each output port of the second level splitter may be configured to connect to one ONT.

[0186] When the detection light source is not turned on, the ONT is configured to receive the first service light from the OLT and determine a first power P0 of the first service light. It should be understood that when the first service light passes through the first gain assembly, the first gain assembly does not generate gain for the first service light. Further, the ONT is configured to report the first power P0 of the first service light to the OLT.

[0187] When the detection light source is turned on, it can be used to separately emit detection light of wavelengths λ1 to λ8 at different moments. In other words, at a certain moment, the detection light source may emit detection light of one central wavelength. For example, detection light of central wavelength λ1 is emitted at time t1, detection light of central wavelength λ2 is emitted at time t2, detection light of central wavelength λ3 is emitted at time t3, ..., detection light of central wavelength λ7 is emitted at time t7, and detection light of central wavelength λ8 is emitted at time t8.

[0188] When the central wavelength of the detected light is λ1, the ONT determines a second power P1 of the received power-altered first service light, when the central wavelength of the detected light is λ2, the ONT determines a second power P2 of the received power-altered first service light, ..., when the central wavelength of the detected light is λ8, the ONT determines a second power P8 of the received power-altered first service light.

[0189] Further, optionally, the ONT is configured to report the determined second power to the OLT as shown in Table 7. In a possible implementation, the ONT can report one second power to the OLT every time the ONT determines a second power, or the ONT can report eight second powers together to the OLT after determining eight second powers. In addition, the ONT can report the first power and the second power together to the OLT, or can report the first power first and then the second power. This is not limited in the present application.

[0190] [Table 7]

[0191] Correspondingly, the OLT is configured to receive second powers from the ONT, where the second powers are, respectively, a second power P1, a second power P2, a second power P3, a second power P4, a second power P5, a second power P6, a second power P7, and a second power P8, and is configured to receive a first power P0 from the ONT and separately calculate a power fluctuation ΔPn, where ΔPn=Pn-P0, and the value of n ranges from 1 to 8.

[0192] Further, the OLT may be configured to determine an output port of the splitter connected to the ONT based on the power fluctuation ΔPn. In a possible implementation, the power fluctuation ΔPn may be compared with the resolution or decision threshold (Δm, which may be set to 0.3 dB, for example) of the PON system to determine whether the power of the signal light received by the OLT changes when the detection light source is turned on and when the detection light source is not turned on. If ΔPn=0, this indicates that the power of the first service light does not change under the detection light of the wavelength λn. Specifically, the detection light of the wavelength λn and the first service light are not incident on the first gain assembly together, and the detection light of the wavelength λn is not transmitted to the second gain assembly. This further indicates that the detection light of wavelength λn is reflected back to the input end by the first optical filter corresponding to the output port of the first splitter, and it may be further determined that the center wavelength corresponding to the first optical filter corresponding to the output port of the first level splitter is λn, so that the output port of the first level splitter connected to the ONT may be determined based on the correspondence (as shown in Table 1) between the output port and the center wavelength of the splitter. If ΔPn=Δm, ΔPn may be recorded as "1", indicating that the power of the first service light changes by one unit under the detection light of wavelength λn. This indicates that both the detection light of wavelength λn and the first service light enter the second gain assembly connected to the first level splitter, and further indicates that the first optical filter corresponding to the output port of the first level splitter passes the detection light of wavelength λn. If ΔPn=2Δm, ΔPn may be recorded as "2", indicating that the power of the first service light changes by two units under the detection light of wavelength λn. This indicates that both the detection light and the first service light reach the second gain assembly connected to the first level splitter and the first gain assembly connected to the second level splitter.

[0193] It should be understood that if both the detection light and the first service light are transmitted to the second gain assembly connected to the first level splitter, the detection light and the first service light act once and the power of the first service light is amplified by Δm. If the detection light and the first service light are transmitted to the first gain assembly connected to the second level splitter, the first service light is amplified by Δm again. In other words, if the detection light and the first service light can be transmitted to both the first gain assembly and the second gain assembly, the first service light is amplified by 2πm.

[0194] For example, ΔP1 to ΔP8 are 02222222, respectively. Specifically, when the central wavelength of the detection light is λ1, the power of the signal light received by the ONT does not change. When the central wavelength of the detection light is λ2, when the central wavelength of the detection light is λ3, when the central wavelength of the detection light is λ4, when the central wavelength of the detection light is λ5, when the central wavelength of the detection light is λ6, when the central wavelength of the detection light is λ7, or when the central wavelength of the detection light is λ8, the power of the signal light received by the ONT changes. When the central wavelength of the detection light is the same as the central wavelength corresponding to the first optical filter, the detection light is reflected back to the input end by the first optical filter. Therefore, the power of the signal light received by the ONT does not change. Therefore, the OLT can determine that the center wavelength corresponding to the first optical filter connected to the ONT is λ1, and based on the correspondence between the center wavelengths and the output ports of the splitters (as shown in Table 1), can determine that the center wavelength λ1 corresponds to output port 1 (port #1) of the first level splitter and corresponds to output port 1 (port #1) of the second level splitter.

[0195] Furthermore, when the central wavelength of the detection light is λ2, the central wavelength of the detection light is λ3, the central wavelength of the detection light is λ4, the central wavelength of the detection light is λ5, the central wavelength of the detection light is λ6, the central wavelength of the detection light is λ7, or the central wavelength of the detection light is λ8, both the detection light and the first service light reach the second gain assembly connected to the first level splitter and the first gain assembly connected to the second level splitter. This indicates that each of the seven central wavelengths of the detection light is different from the central wavelength corresponding to the first optical filter. Therefore, the power of the signal light received by the ONT changes. The OLT can determine that the ONT is not connected to port #2, port #3, port #4, port #5, port #6, port #7, or port #8 of the first level splitter, and can further determine that the ONT is not connected to port #2, port #3, port #4, port #5, port #6, port #7, or port #8 of the second level splitter.

[0196] Based on the above, when it is determined that the power variations ΔP1 to ΔP8 are 02222222, respectively, the OLT can determine that the ONT is connected to port #1 of the first level splitter and port #1 of the second level splitter.

[0197] For example, ΔP1 to ΔP8 are 12222220, respectively. Specifically, when the central wavelength of the detection light is λ1, the power of the signal light received by the ONT changes by one unit. When the central wavelength of the detection light is λ2, the central wavelength of the detection light is λ3, the central wavelength of the detection light is λ4, the central wavelength of the detection light is λ5, the central wavelength of the detection light is λ6, or the central wavelength of the detection light is λ7, the power of the first service light received by the ONT changes by two units. When the central wavelength of the detection light is λ8, the power of the first service light received by the ONT does not change. The OLT can determine, based on ΔP8=0, that the detection light of wavelength λ8 is reflected back to the input end by the first optical filter of the first level splitter and cannot reach the second level splitter. Therefore, it can be determined that the central wavelength corresponding to the first optical filter corresponding to the output port of the first level splitter connected to the ONT is λ8. Further, the OLT may determine that the central wavelength λ8 corresponds to the port #8 of the first level splitter based on the correspondence (as shown in Table 3) between the central wavelengths and the output ports of the splitters. The OLT may determine that the first service light generates gain only in the second gain assembly connected to the first level splitter and is reflected back by the first optical filter corresponding to the output port of the second level splitter based on ΔP1=1. Therefore, it may be determined that the central wavelength corresponding to the first optical filter corresponding to the output port of the first level splitter connected to the ONT is λ1. With reference to the correspondence (as shown in Table 2) between the central wavelengths and the output ports of the splitters, the OLT may determine that the central wavelength λ1 corresponds to the port #1 of the second level splitter.

[0198] Furthermore, when the central wavelength of the detection light is λ2, the central wavelength of the detection light is λ3, the central wavelength of the detection light is λ4, the central wavelength of the detection light is λ5, the central wavelength of the detection light is λ6, or the central wavelength of the detection light is λ7, the power of the first service light received by the ONT changes by 2 units. That is, under the detection light of six wavelengths, the detection light and the first service light reach the second gain assembly connected to the first level splitter and the first gain assembly connected to the second level splitter. This indicates that each of the detection light of six wavelengths is different from the central wavelength corresponding to the first optical filter. Therefore, the power of the first service light received by the ONT changes by 2 units. The OLT may determine that the ONT is not connected to port #2, port #3, port #4, port #5, port #6, or port #7 of the first level splitter, and may further determine that the ONT is not connected to port #2, port #3, port #4, port #5, port #6, or port #7 of the second level splitter.

[0199] Based on the above, when it is determined that the power variations ΔP1 to ΔP8 are 12222220, respectively, the OLT can determine that the ONT is connected to port #8 of the first level splitter and port #1 of the second level splitter.

[0200] Note that Δm can be a specific value, an interval, or a function.

[0201] FIG. 10c is a schematic diagram of yet another PON system according to the present application. The PON system may include a detection light source, a WDM, an OLT, an ODN, and an ONT. For example, the ODN is the ODN shown in FIG. 5b (reference is made to the above related description, and the details are not described again here). The WDM may be configured to couple the received detection light and the first service light to a feeder fiber, and transmit the detection light and the first service light to a first level splitter through the feeder fiber. Each output port of the first level splitter may be configured to connect to one second level splitter, and each output port of the second level splitter may be configured to connect to one ONT.

[0202] When the detection light source is not turned on, the ONT is configured to receive the first service light from the OLT and determine a first power P0 of the first service light. It should be understood that when the first service light passes through the first gain assembly, the first gain assembly does not generate gain for the first service light. Further, the ONT is configured to report the first power P0 of the first service light to the OLT.

[0203] When the detection light source is turned on, the detection light source can be used to separately emit detection light of wavelengths λ1 to λ3 at different moments. In other words, at a certain moment, the detection light source may emit detection light of one central wavelength. For example, at time t1, detection light of central wavelength λ1 is emitted, at time t2, detection light of central wavelength λ2 is emitted, and at time t3, detection light of central wavelength λ3 is emitted.

[0204] When the central wavelength of the detected light is λ1, the ONT determines a second power P1 of the received power-altered first service light, when the central wavelength of the detected light is λ2, the ONT determines a second power P2 of the received power-altered first service light, and when the central wavelength of the detected light is λ3, the ONT determines a second power P3 of the received power-altered first service light.

[0205] Further, optionally, the ONT is configured to report the determined second power to the OLT. Correspondingly, the OLT can receive the second power from the ONT. For details, please refer to the above related description. Details are not repeated here.

[0206] Further, the OLT may be configured to determine the output port of the splitter connected to the ONT based on the power fluctuation ΔPn. In a possible implementation, the power fluctuation ΔPn may be compared with the resolution or decision threshold (Δm, which may be set to 0.3 dB, for example) of the PON system to determine whether the power of the signal light received by the OLT changes when the detection light source is turned on and when the detection light source is not turned on. For the value recorded in ΔPn, please refer to the related description above. Details will not be repeated here.

[0207] For example, an ONT is connected to output port 1 of a second level splitter, and the corresponding power fluctuations are ΔP1=P1-P0=0, ΔP2=P2-P0=1, and ΔP3=P3-P0=1. That is, ΔP1 to ΔP3 are 011, respectively. That is, if the OLT determines that the power fluctuations ΔP1 to ΔP3 are 011, respectively, it can determine that the ONT is connected to the #1 port of the second level splitter.

[0208] In another example, the ONT is connected to output port #7 of the second level splitter, and the corresponding power fluctuations are ΔP1=P1-P0=0, ΔP2=P2-P0=0, and ΔP3=P3-P0=0. That is, ΔP1 to ΔP3 are each 000. In other words, if the OLT determines that the power fluctuations ΔP1 to ΔP3 are each 000, it can determine that the ONT is connected to port #7 of the second level splitter.

[0209] It should be noted that the above table showing the correspondences is merely an example and may show a similar correspondence or set of correspondences in an implementation process.

[0210] It is further noted that when the second level splitter includes eight ports, seven of the ports may be identified and the eighth port may be determined according to an exclusion method.

[0211] Based on the above and the same concept, the present application provides a method for identifying a port of a splitter. Please refer to the description of FIG. 11. The method for identifying a port of a splitter may be applied to the PON system shown in any one of the embodiments of FIG. 8 to FIG. 10c. It can also be understood that the method for identifying a port of a splitter may be implemented based on the PON system shown in any one of the embodiments of FIG. 8 to FIG. 10c.

[0212] 11 is a schematic flowchart of a method for identifying a port of a splitter according to the present application. The method can be applied to an optical network system according to any one of the above-mentioned embodiments. The method includes the following steps:

[0213] Step 1101: Receive a first service optical from an optical line terminal, and determine a first power of the first service optical.

[0214] Herein, the first service light from the optical line terminal may be received when the detection light source is not turned on.

[0215] Step 1102: Receive a power-modified first service light from a first power modifying assembly, and determine a second power of the power-modified first service light.

[0216] The power-modified first service light is obtained by modifying the power of the first service light by the first power modifying assembly based on the received first detected light, the central wavelength of the first detected light is the central wavelength that a first optical filter corresponding to the first power modifying assembly passes, and the central wavelengths of the detected light that different first optical filters pass or do not pass are different. The first power and the second power can be used to determine an output port of a splitter connected to an optical network termination device.

[0217] In this specification, the power-modified first service light is obtained by modifying the power of the first service light by the first power modifying assembly based on the received first detection light. In other words, after the detection light source is turned on, the detection light emitted by the detection light source is transmitted to the first power modifying assembly together with the first service light after passing through the corresponding first optical filter, and the first power modifying assembly can modify the power of the first service light, so that the power-modified first service light can be obtained.

[0218] Both steps 1101 and 1102 can be performed by an optical network termination device. For details, please refer to the related description above. Details will not be repeated here.

[0219] In a possible implementation form, the output port of the splitter connected to the optical network termination device is determined based on the first power and the second power, may be performed by the optical network termination device, or may be performed by the optical line termination device. For details, please refer to the above related description. Details are not repeated here.

[0220] Further, optionally, the power fluctuation may be determined based on the second power and the first power, a central wavelength of the detected light that the first optical filter passes or does not pass is determined based on the power fluctuation and the central wavelength of the first detected light, and an output port of the splitter connected to the optical network termination device is determined based on the central wavelength of the detected light that the first optical filter passes or does not pass and a correspondence between the central wavelength and the output port of the splitter.

[0221] From step 1101 and step 1102, it can be seen that the central wavelengths of the detection light that different first optical filters pass or do not pass are different. When both the detection light and the first service light are transmitted to the first power modifying assembly, the first power modifying assembly can modify the power of the first service light. When only the first service light is transmitted to the first power modifying assembly, the first power modifying assembly does not modify the power of the first service light, so that the central wavelength of the corresponding detection light can be determined based on the power of the first service light, the corresponding first optical filter can be determined based on the central wavelength of the detection light, and the port of the splitter connected to the optical network termination device can be further determined based on the determined first optical filter.

[0222] In the above-described embodiments, the gain assembly may alternatively be replaced with an attenuation assembly, and the gain assembly and attenuation assembly may be collectively referred to as a power modifying assembly.

[0223] In the embodiments of the present application, unless otherwise specified or there is no logical contradiction, the terms and / or descriptions between different embodiments are consistent and may be cross-referenced, and the technical features of different embodiments may be combined based on their internal logical relationships to form a new embodiment.

[0224] In this application, "uniformity" does not mean absolute uniformity, and allows for engineering error, for example, as described above, "good channel uniformity." Equal does not mean absolute equality, and allows for engineering error. For example, the aforementioned "the photon energy of the detection light is equal to the energy difference between the E3 / E2 energy level and the E1 energy level," and in another example, the aforementioned "the energy of the input signal light is equal to the energy difference between the E2 energy level and the E1 energy level." At least one means one or more, and "multiple" means two or more, for example, the aforementioned "at least one first optical filter." Another example is the aforementioned "at least one fixed wavelength." The term "and / or" describes a relational relationship between related objects and represents that three relations may exist. For example, A and / or B can represent the following cases, namely, when only A exists, when both A and B exist, and when only B exists, and A and B can be singular or plural. An example is, as mentioned above, "the detection light source may be a tunable light source, and / or a combination of an optical switch and a light source emitting at least one fixed wavelength." In the text description of this application, the character " / " usually indicates an "or" relationship between related objects, for example, the "E3 / E2 energy level" mentioned above. In addition, in this application, the word "example" is used to represent giving an example, illustration, or explanation. Any embodiment or design manner described as an "example" in this application should not be described as being preferred or having more advantages over another embodiment or design manner. Alternatively, the word "example" may be used to present a concept in a particular manner and may be understood as not constituting a limitation to this application. In this application, the power of an optical signal may also be referred to as optical power.

[0225] It can be understood that various numbers in the embodiments of the present application are used merely to distinguish for ease of description, and are not used to limit the scope of the embodiments of the present application. The sequence numbers of the above processes do not mean the execution sequence, and the execution sequence of the processes should be determined based on the functions and internal logic of the processes. Terms such as "first", "second", etc. are used to distinguish similar objects, but do not necessarily indicate a specific order or sequence. In addition, the terms "include", "have", and any variations thereof are intended to cover non-exclusive inclusion, for example, including a series of steps or units. A method, system, product, or device is not necessarily limited to the literally recited steps or units, and may include other steps or units that are not literally recited or are inherent to such a process, method, product, or device.

[0226] Although the present application is described with reference to specific features and embodiments thereof, it is clear that various modifications and combinations may be made thereto without departing from the scope of the present application. Correspondingly, the specification and the accompanying drawings are merely examples for illustrating the solutions defined by the appended claims, and any or all of the modifications, variations, combinations or equivalents are deemed to encompass the scope of the present application.

[0227] It is obvious that those skilled in the art can make various modifications and variations to this application without departing from the scope of the present invention. This application is intended to cover these modifications and variations, provided that they fall within the scope of protection defined by the following claims and their equivalent technologies.

Claims

1. An optical distribution network comprising at least one splitter cascaded from an optical line terminal to an Nth level, M1 first optical filters, and M2 first power changing assemblies, where N, M1, and M2 are all positive integers, each of the at least one splitter includes at least two output ports, each of the at least two output ports corresponding to at least one first optical filter, different output ports corresponding to different first optical filters, and the different first optical filters pass or do not pass different central wavelengths of light; An optical distribution network, wherein each output port of the Nth level splitter further corresponds to a first power changing assembly, the first power changing assembly being configured to change the power of the first service light when a first detection light emitted by a detection light source is transmitted to the first power changing assembly together with the first service light from the optical line terminal after passing through a corresponding first optical filter, and the Nth level splitter is configured to connect to an optical network terminal.

2. N is an integer greater than 1, a first optical filter corresponding to any output port of a K-th level splitter is different from a first optical filter corresponding to any output port of a H-th level splitter, both H and K being positive integers different from each other; 2. The optical distribution network of claim 1, wherein the K level splitter and the H level splitter are any two of at least one splitter cascaded up to the N level.

3. N is an integer greater than 1, an output port of each splitter in an Lth level corresponds to a second power modifying assembly, the Lth level splitters being splitters other than the Nth level splitters, L being a positive integer; 2. The optical distribution network of claim 1, wherein the second power modifying assembly is configured to modify the power of the first service light from the optical line terminal when a second detection light emitted by a second detection light source is transmitted to the second power modifying assembly together with the first service light after passing through a corresponding first optical filter.

4. 4. The optical distribution network of claim 3, wherein a first optical filter corresponding to the output port of the L-level splitter is the same as a first optical filter corresponding to the output port of the N-level splitter.

5. an i-th output port, a first optical filter corresponding to the i-th output port, and a first power changing assembly corresponding to the i-th output port or a second power changing assembly corresponding to the i-th output port; the i-th output port, the first optical filter corresponding to the i-th output port, and the first power modifying assembly corresponding to the i-th output port or the second power modifying assembly corresponding to the i-th output port are sequentially integrated together; or the first optical filter corresponding to the i-th output port is integrated into the i-th output port, and the first power modifying assembly corresponding to the i-th output port or the second power modifying assembly corresponding to the i-th output port is connected in series with the integrated first optical filter corresponding to the i-th output port; or the first optical filter corresponding to the i-th output port is connected in series to the i-th output port, and the first power modifying assembly corresponding to the i-th output port or the second power modifying assembly corresponding to the i-th output port is connected in series to the first optical filter corresponding to the i-th output port; 5. The optical distribution network of claim 1, wherein the i-th output port is any one of at least two output ports of any splitter in at least one splitter cascaded up to the N level, where i is a positive integer.

6. the first power modifying assembly is a first gain assembly and the second power modifying assembly is a second gain assembly; or 4. The optical distribution network of claim 3, wherein the first power modifying assembly is a first attenuation assembly and the second power modifying assembly is a second attenuation assembly.

7. the first power modifying assembly further corresponding to a second optical filter; 7. The optical distribution network of claim 1, wherein the second optical filter is configured to reflect the first detected light from the first power modifying assembly back to the first power modifying assembly.

8. 8. An optical network system comprising an optical network termination device and an optical distribution network according to any one of claims 1 to 7, wherein the optical network termination device is configured to determine a first power of a first service light from the optical distribution network and a second power of a power-modified first service light, The first power and the second power are used to determine an output port of a splitter connected to the optical network termination unit.

9. The optical network system further includes an optical line terminal; The optical line terminal comprises: receiving the first power and the second power from the optical network termination; determining a power fluctuation based on the first power and the second power; determining a central wavelength of light that a first optical filter passes or does not pass based on the power fluctuation and the central wavelength of the first detected light; 9. The optical network system of claim 8, configured to determine the output port of the splitter connected to the optical network termination device based on the center wavelength of the light that the first optical filter passes or does not pass and a correspondence between center wavelengths and output ports of the splitter.

10. The optical network termination device determining a power fluctuation based on the first power and the second power; determining a central wavelength of light that a first optical filter passes or does not pass based on the power fluctuation and the central wavelength of the first detected light; 10. The optical network system of claim 8, further configured to determine the output port of the splitter connected to the optical network termination device based on the center wavelength of the light that the first optical filter passes or does not pass and a correspondence between center wavelengths and output ports of a splitter.

11. The detection light source is A tunable light source; and a combination of an optical switch and a light source emitting at least one fixed wavelength, wherein the optical switch is configured to control one of the light sources emitting at least one fixed wavelength to output detection light, and a central wavelength of the detection light output by the light source corresponds to a central wavelength that the first optical filter passes or does not pass.

12. at least two output ports; and at least one first optical filter corresponding to each of the at least two output ports; Equipped with the different output ports correspond to different first optical filters, and the different first optical filters pass or do not pass different central wavelengths of light; A splitter, wherein each output port further corresponds to a power modifying assembly, the power modifying assembly being configured to modify a power of the first service light when a first detection light emitted by a detection light source is transmitted to the power modifying assembly together with a first service light from an optical line terminal after passing through a corresponding first optical filter.

13. The splitter of claim 12 , wherein the power modifying assembly is a gain assembly or an attenuation assembly.

14. 1. A method for identifying a port of a splitter, comprising: receiving, by an optical network termination unit, a first service light from an optical line termination unit and determining a first power of the first service light; receiving, by the optical network termination device, a power-modified first service light from a first power modifying assembly, and determining a second power of the power-modified first service light, wherein the power-modified first service light is obtained by modifying the power of the first service light when the first power modifying assembly receives, together with the first service light, a first detection light emitted by a detection light source after passing through a corresponding first optical filter, and a central wavelength of the first detection light is a central wavelength passed by the first optical filter corresponding to the first power modifying assembly, and central wavelengths of light passed or not passed by different first optical filters are different; The method of claim 1, wherein the first power and the second power are used to determine an output port of a splitter connected to the optical network termination unit.

15. The method comprises: determining, by the optical network termination unit, a power fluctuation based on the second power and the first power; determining, by the optical network termination unit, a central wavelength of light that the first optical filter will pass or not pass based on the power fluctuations and the central wavelength of the first detected light; 15. The method of claim 14, further comprising: determining, by the optical network termination device, the output port of the splitter connected to the optical network termination device based on the center wavelength of the light that the first optical filter passes or does not pass and a correspondence between center wavelengths and output ports of splitters.

16. The method comprises: receiving, by the optical line termination, the first power and the second power from the optical network termination; determining, by the optical line terminal, a power fluctuation based on the first power and the second power; determining, by the optical line terminal, a central wavelength of light that the first optical filter will pass or not pass based on the power fluctuations and the central wavelength of the first detected light; 15. The method of claim 14, further comprising: determining, by the optical line termination, the output port of the splitter connected to the optical network termination based on the center wavelength of the light that the first optical filter passes or does not pass and a correspondence between center wavelengths and output ports of splitters.

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