Optical splitter, optical distribution network, and passive optical network

Abstract

Provided in embodiments of the present application are an optical splitter, an optical distribution network, and a passive optical network, used for determining a network topology. The optical splitter provided in the embodiments of the present application comprises a beam splitting unit, a plurality of first waveguides, and a plurality of delay units. The beam splitting unit comprises a common port and a plurality of branch ports. The plurality of first waveguides are connected to the plurality of branch ports in a one-to-one correspondence, and the plurality of delay units are connected to the plurality of first waveguides in a one-to-one correspondence. Any delay unit among the plurality of delay units comprises a beam splitting and combining module and a delay module. The beam splitting and combining module is coupled to the corresponding first waveguide. The beam splitting and combining module is used for splitting a second optical signal from a first optical signal in a first region of the first waveguide, and coupling the second optical signal passing through the delay module to a second region of the first waveguide. The delay module is used for providing an optical path difference between the first optical signal and the second optical signal. Among the plurality of delay units, delay modules of different delay units are used for providing different optical path differences.

Description

A splitter, an optical fiber distribution network, and a passive optical network

[0001] This application claims priority to Chinese Patent Application No. 202411527421.X, filed on October 29, 2024, entitled "A Fiber Splitter, Fiber Distribution Network and Passive Optical Network", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical communication, and more particularly to a splitter, an optical fiber distribution network, and a passive optical network. Background Technology

[0003] Passive optical network (PON) is a point-to-multipoint network architecture, consisting of an optical line termination (OLT), an optical distribution network (ODN), and multiple optical network units (ONUs). The OLT connects to multiple ONUs through the ODN.

[0004] ODN includes one or more optical splitters, which are used to divide the optical signal from the OLT into multiple beams for transmission to different ONUs. ODN typically splits the light according to power; the splitter divides the signal from the uplink port (OLT direction) into multiple beams according to power, which are then transmitted to different ONUs through multiple downlink ports.

[0005] Because optical splitters distribute power, in the uplink direction, they cannot map the optical signals from the ONU to their ports, making it impossible to determine the ODN network topology. When a component in the PON fails (e.g., a splitter failure, fiber breakage, ONU failure), troubleshooting must be performed on each splitter and port in the ODN to pinpoint the fault location, leading to maintenance difficulties. Summary of the Invention

[0006] This application provides an optical splitter, an optical fiber distribution network, and a passive optical network for determining network topology.

[0007] In a first aspect, embodiments of this application provide a beam splitter. The beam splitter includes a beam-splitting unit, a plurality of first waveguides, and a plurality of delay units. The beam-splitting unit includes a common port and a plurality of branch ports. Each of the plurality of first waveguides is connected to one of the plurality of branch ports, and each of the plurality of delay units is connected to one of the plurality of first waveguides. Each of the plurality of delay units includes a beam-splitting and beam-combining module and a delay module. The beam-splitting and beam-combining module is coupled to the corresponding first waveguide. The beam-splitting and beam-combining module is used to separate a second optical signal from a first optical signal in a first region of the first waveguide, and to couple the second optical signal, which has passed through the delay module, to a second region of the first waveguide. The delay module is used to provide an optical path difference between the first optical signal and the second optical signal. In the plurality of delay units, the delay modules of different delay units are used to provide different optical path differences.

[0008] In this embodiment, the optical path difference of the delay module corresponds to the branch port connected to the delay unit where the delay module is located. The magnitude of the optical path difference of the delay module indicates the corresponding branch port, thus distinguishing different branch ports of the beam splitting unit. After the first optical signal passes through the beam splitter, it outputs a first optical signal and a second optical signal. A device connected to the beam splitter (e.g., an OLT or ONU) receives this optical signal and can determine which branch port of the beam splitter the signal flows through based on the magnitude of the optical path difference between the first and second optical signals, thereby associating the optical signal with the corresponding branch port and determining the network topology.

[0009] In one alternative implementation, the beam splitting and combining module includes a splitter and a combiner. One end of the splitter is coupled to a first region, and the other end is coupled to a first end of the delay module. One end of the combiner is coupled to a second region, and the other end is coupled to a second end of the delay module.

[0010] In this embodiment, a target region is also included between the first region and the second region on the first waveguide. The splitter, delay module, combiner, and target region constitute an MZI structure. The MZI structure has the characteristic of interference superposition after beam splitting. The delay superposition of optical signals can be achieved by introducing a delay module, and the structure is simple and easy to implement.

[0011] In one alternative implementation, the splitter and combiner are directional couplers. Directional couplers are simple in structure and easy to implement, which can reduce the difficulty and cost of manufacturing.

[0012] In one optional implementation, the beam splitting and combining module includes a splitter and a combiner. A first waveguide includes a target region located between a first region and a second region. The common port of the splitter is connected to the first region of the first waveguide, a first branch port of the splitter is connected to a first end of the target region, and a second branch port is coupled to a third end of the delay module. The common port of the combiner is connected to the second region of the first waveguide, a third branch port of the combiner is connected to a second end of the target region, and a fourth branch port is coupled to a fourth end of the delay module.

[0013] In this embodiment, the splitter, delay module, combiner, and target region constitute an MZI structure. The MZI structure features interference superposition after beam splitting, and the delay superposition of optical signals can be achieved by introducing a delay module, making the structure simple and easy to implement.

[0014] In one optional implementation, the optical splitter includes a first chip and a second chip. A beam-splitting unit, multiple first waveguides, and a splitter and combiner for multiple delay units are located on the first chip. The first chip also includes a first coupler and a second coupler. Delay modules for the multiple delay units are located on the second chip. The second chip also includes a third coupler and a fourth coupler, with the third coupler, delay modules, and fourth coupler connected sequentially. The splitter is connected to the first coupler, and the combiner is connected to the second coupler. The third coupler of the second chip is used for coupling with the first coupler of the first chip, and the fourth coupler of the second chip is used for coupling with the second coupler of the first chip.

[0015] In this embodiment, the delay module and the first waveguide are disposed on chips with different waveguide core materials, thereby increasing the refractive index difference between the delay module and the first waveguide relative to the cladding material. A delay module of unit length can provide a larger optical path difference (relative to the first waveguide), thereby reducing the length of the delay module, reducing the overall volume of the beam splitter, and achieving miniaturization of the beam splitter.

[0016] In one optional implementation, the beam splitter is a planar waveguide PLC chip. The beam splitting unit, multiple first waveguides, and splitters and combiners for multiple delay units are located on the first layer of the PLC chip. The first layer also includes a fifth coupler and a sixth coupler. The delay modules for the multiple delay units are located on the second layer of the PLC chip. The waveguides in the first and second layers are made of different materials. The second layer also includes a seventh coupler and an eighth coupler, with the seventh coupler, delay modules, and eighth coupler connected sequentially. The splitter is connected to the fifth coupler, and the combiner is connected to the sixth coupler. The seventh coupler in the second layer is used to couple with the fifth coupler in the first layer, and the eighth coupler in the second layer is used to couple with the sixth coupler in the first layer.

[0017] In this embodiment, the delay module and the first waveguide are disposed on different layers of the chip, so that the waveguide materials of different layers are different, which increases the refractive index difference between the delay module and the first waveguide relative to the cladding material. The delay module per unit length can provide a larger optical path difference (relative to the first waveguide), thereby reducing the length of the delay module, reducing the volume of the entire beam splitter, and realizing the miniaturization of the beam splitter.

[0018] In one alternative implementation, the optical splitter includes a chip, a beam-splitting unit, multiple first waveguides, and a splitter and combiner for the delay unit located on the chip. The chip also includes a ninth coupler and a tenth coupler. The splitter is connected to the ninth coupler, and the combiner is connected to the tenth coupler. The delay module is an optical fiber, with both ends of the fiber coupled to the ninth and tenth couplers on the chip, respectively.

[0019] In this embodiment, the first waveguide is disposed on the chip, and the delay module is disposed of as an optical fiber outside the chip. Since optical fiber has low loss and is flexible, it offers the advantage of low-loss delay.

[0020] In one alternative implementation, the delay module includes a second waveguide. The first and second ports of the beam splitter / combiner module are connected to a first region and a second region of the first waveguide, respectively, and the third and fourth ports are coupled to both ends of the second waveguide, respectively. The beam splitter / combiner module is used to couple optical signals from the first and third ports to the second and fourth ports.

[0021] In this embodiment, the beam splitter and combiner module and the second waveguide constitute a micro-ring MRR structure. The MRR structure is characterized by its simple structure and low loss, and can realize a low insertion loss and easily implemented delay superposition structure.

[0022] In one alternative implementation, the beam splitter includes a first chip and a second chip. A beam-splitting and combining module comprising a beam-splitting unit, multiple first waveguides, and multiple delay units is located on the first chip. The first chip also includes an eleventh coupler and a twelfth coupler. Second waveguides of the multiple delay units are located on the second chip. The second chip also includes a thirteenth coupler and a fourteenth coupler, with the thirteenth coupler, second waveguides, and fourteenth coupler connected sequentially. The third and fourth ports of the beam-splitting and combining module are connected to the eleventh and twelfth couplers, respectively. The thirteenth coupler of the second chip is used for coupling with the eleventh coupler of the first chip, and the fourteenth coupler of the second chip is used for coupling with the twelfth coupler of the first chip.

[0023] In this embodiment, the second waveguide and the first waveguide are disposed on a chip with different waveguide core materials, thereby increasing the refractive index difference between the second waveguide and the first waveguide relative to the cladding material. The second waveguide per unit length can provide a larger optical path difference (relative to the first waveguide), thereby reducing the length of the second waveguide, reducing the volume of the entire beam splitter, and realizing the miniaturization of the beam splitter.

[0024] In one optional implementation, the beam splitter is a planar optical waveguide PLC chip. The beam splitting unit, multiple first waveguides, and a beam combining module for multiple delay units are located on the first layer of the PLC chip. The first layer also includes a fifteenth coupler and a sixteenth coupler. The delay modules for the multiple delay units are located on the second layer of the PLC chip. The waveguides in the first and second layers are made of different materials. The second layer also includes a seventeenth coupler and an eighteenth coupler, which are connected sequentially to the seventeenth coupler, the delay modules, and the eighteenth coupler. The third and fourth ports of the beam combining module are connected to the fifteenth and sixteenth couplers, respectively. The seventeenth coupler of the second layer is used to couple with the fifteenth coupler of the first layer, and the eighteenth coupler of the second layer is used to couple with the sixteenth coupler of the first layer.

[0025] In this embodiment, the second waveguide and the first waveguide are disposed on different layers of the chip, so that the waveguide materials of the different layers are different, which increases the refractive index difference between the second waveguide and the first waveguide relative to the cladding material. The second waveguide per unit length can provide a larger optical path difference (relative to the first waveguide), thereby reducing the length of the second waveguide, reducing the volume of the entire beam splitter, and realizing the miniaturization of the beam splitter.

[0026] In one alternative implementation, the beam splitter includes a chip, a beam-splitting unit, multiple first waveguides, and a beam-splitting and combining module with multiple delay units located on the chip. The chip also includes a nineteenth coupler and a twentieth coupler. The third and fourth ports of the beam-splitting and combining module are connected to the nineteenth and twentieth couplers, respectively. The delay modules are optical fibers, with both ends of the optical fibers coupled to the nineteenth and twentieth couplers on the chip, respectively.

[0027] In this embodiment, the first waveguide is disposed on the chip, and the second waveguide is disposed on an optical fiber outside the chip. Since optical fibers have low loss and are flexible, they offer the advantage of low-loss delay.

[0028] In one alternative implementation, the beam splitter / combiner module and the second waveguide constitute a micro-ring MRR. If the intensity of the second optical signal is less than the intensity of the first optical signal, the micro-ring is set to an extremely undercoupled state; if the intensity of the second optical signal is greater than the intensity of the first optical signal, the micro-ring is set to an extremely overcoupled state.

[0029] In this embodiment, if the intensity of the second optical signal is less than the intensity of the first optical signal, the micro-ring is set to an extremely undercoupled state to reduce the static extinction ratio at the resonant wavelength of the micro-ring, thereby reducing the loss of the optical signal with the resonant wavelength passing through the structure. If the intensity of the second optical signal is greater than the intensity of the first optical signal, the micro-ring is set to an extremely overcoupled state, which can also reduce the static extinction ratio at the resonant wavelength of the micro-ring, thereby reducing the loss of the optical signal with the resonant wavelength passing through the structure.

[0030] In one alternative implementation, the delay module further includes an attenuation submodule, which is used to attenuate the resonant signal within the microring when the intensity of the second optical signal is less than the intensity of the first optical signal.

[0031] In this embodiment, the attenuation submodule is used to attenuate the resonant signal within the microring when the intensity of the second optical signal is less than the intensity of the first optical signal, so as to more flexibly set the coupling state of the microring.

[0032] In one alternative implementation, among multiple delay units, the delay module includes a second waveguide, and the lengths of the second waveguides of different delay units are different.

[0033] In this embodiment, different branch ports of the beam splitting unit are distinguished by using second waveguides of different lengths in different delay units, thus enabling the identification of different branch ports. This structure is simple and easy to implement.

[0034] In one alternative implementation, the beam splitter is a planar waveguide PLC chip. The refractive index difference between the waveguide core and cladding of the second chip is greater than the refractive index difference between the waveguide core and cladding of the first chip.

[0035] In one alternative implementation, the refractive index difference between the waveguide core layer and the cladding layer of the second layer is greater than the refractive index difference between the waveguide core layer and the cladding layer of the first layer.

[0036] In one alternative implementation, the waveguide core material of the delay module is SiN, and the waveguide core material of the multiple first waveguides is SiO2 doped with germanium or silver ions.

[0037] In the embodiments of this application, this material combination is a mature process in the industry, which can realize optical waveguides with low insertion loss.

[0038] Secondly, embodiments of this application provide an optical distribution network (ODN). The ODN includes one or more optical splitters, which are the optical splitters described in the first aspect or its implementation.

[0039] In one alternative implementation, the multiple beam splitters include multi-stage beam splitters, in which the optical path difference of the delay modules in different stages of the beam splitters is different.

[0040] In this embodiment of the application, the optical path difference of different levels of optical splitters is made different. Then, the receiving end of the optical signal (e.g., OLT or ONU) can identify the optical path difference experienced by the signal in the multi-level optical splitters it passes through based on the difference between the optical path differences between different levels of optical splitters. This allows the branch ports of each level of optical splitter that the optical signal passes through to be determined, and the network topology to be determined in the network of multi-level optical splitters.

[0041] Thirdly, embodiments of this application provide a passive optical network (PON). This PON includes the ODN described in the second aspect or its implementation.

[0042] The beneficial effects of the second and third aspects are described in the first aspect and will not be repeated here. Attached Figure Description

[0043] Figure 1 is a schematic diagram of the structure of the PON network provided in this application;

[0044] Figure 2 is a schematic diagram of a beam splitter provided in an embodiment of this application;

[0045] Figure 3 is another structural schematic diagram of the beam splitter provided in an embodiment of this application;

[0046] Figure 4 is a schematic diagram of a splitter including a splitter and a combiner provided in an embodiment of this application;

[0047] Figure 5 is another structural schematic diagram of a splitter including a splitter and a combiner provided in an embodiment of this application;

[0048] Figure 6a is a schematic diagram of a beam splitter including multiple chips provided in an embodiment of this application;

[0049] Figure 6b is another structural schematic diagram of a beam splitter including multiple chips provided in an embodiment of this application;

[0050] Figure 7 is a schematic diagram of a beam splitter including multiple chip layers provided in an embodiment of this application;

[0051] Figure 8 is a schematic diagram of a splitter including a chip and an optical fiber provided in an embodiment of this application;

[0052] Figure 9 is a schematic diagram of a beam splitter including a beam splitting and combining module provided in an embodiment of this application;

[0053] Figure 10 is a schematic diagram of a beam splitter including multiple chips and beam splitting and combining modules provided in an embodiment of this application;

[0054] Figure 11 is a schematic diagram of a beam splitter including multiple chip layers and beam splitting and combining modules provided in an embodiment of this application;

[0055] Figure 12 is a schematic diagram of a beam splitter including a chip, a beam splitting and combining module and an optical fiber provided in an embodiment of this application;

[0056] Figure 13 is a schematic diagram of the structure of an ODN provided in an embodiment of this application. Detailed Implementation

[0057] The embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0058] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of units is not necessarily limited to those units, but may include other units not explicitly listed or inherent to those processes, methods, products, or apparatuses. Additionally, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can be expressed as: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0059] Passive Optical Network (PON) is an important component of optical communication networks. PON is a point-to-multipoint fiber optic transmission and access technology. As shown in Figure 1, PON includes an Optical Line Terminal (OLT), an Optical Distribution Network (ODN), and Optical Network Units (ONUs). In a PON network, the OLT is called the central office, and the ONUs are called terminals. The central office OLT is connected to multiple ONUs through the ODN.

[0060] The signal transmission direction from the OLT to the ODN is downlink, and signal transmission is achieved through broadcasting. The signal transmission direction from the ONU to the OLT is uplink. Multiple ONUs under the same ODN are connected to the same OLT. In the uplink direction, multiple ONUs communicate with the OLT using time-division multiplexing, and multiple ONUs share the bandwidth of one OLT.

[0061] As shown in Figure 1, an ODN includes one or more optical splitters (also called fiber optic splitters). In the downlink transmission direction, the optical splitter divides the optical signal from the OLT into multiple beams and transmits them to different ONUs; in the uplink transmission direction, the optical splitter couples the optical signals from different ONUs into one beam and transmits it to the OLT.

[0062] In the downlink direction, the optical splitter splits the optical signal according to a preset optical power ratio, and the ports of the splitter in the downlink direction are allocated according to power. In the uplink direction, the optical splitter cannot map the optical signal from the ONU to the splitter port, making it impossible to determine the network topology. When a section of the PON network fails (e.g., fiber breakage, splitter failure, ONU failure, etc.), it is necessary to troubleshoot each splitter and each splitter port in the ODN to determine the fault location, leading to operational and maintenance difficulties.

[0063] To achieve network topology identification of an ODN, this application embodiment provides an optical splitter, an ODN, and a PON network. This application embodiment distinguishes different branch ports of the optical splitter by setting different delay modules on different branches of the optical splitter, thereby achieving network topology identification. Figure 2 is a schematic diagram of the structure of the optical splitter provided in this application embodiment. As shown in Figure 2, the optical splitter 2000 provided in this application embodiment includes: a beam splitting unit 2100, multiple first waveguides 2200, and multiple delay units 2300. The beam splitting unit 2100 includes a common port 2110 and multiple branch ports 2120.

[0064] The common port 2110 is used to connect to the uplink OLT, or to a higher-level optical splitter in the uplink direction. Multiple first waveguides 2200 are connected one-to-one with multiple branch ports 2120, and multiple delay units 2300 are connected one-to-one with multiple first waveguides 2200.

[0065] Any of the multiple delay units 2300 includes a beam splitter / combiner module 2310 and a delay module 2320. The beam splitter / combiner module 2310 on the delay unit 2300 is coupled to the first waveguide 2200 corresponding to the delay unit 2300 (i.e., the first waveguide 2200 connected to the delay unit 2300).

[0066] The first waveguide 2200 includes a first region 2210 and a second region 2220. A beam splitter / combiner module 2310 is used to separate a second optical signal from the first optical signal in the first region 2210 and couple the second optical signal to the second region 2220. A delay module 2320 is used to provide the optical path difference between the first and second optical signals.

[0067] In this embodiment of the application, in order to distinguish the different branch ports 2120 of the beam splitting unit 2100, the delay modules 2320 of the multiple delay units 2300 provide different optical path differences. For example, as shown in FIG2, the optical path difference of the delay modules 2320 in the multiple delay units 2300 from top to bottom gradually increases.

[0068] In this embodiment, the optical path difference of the delay module 2320 corresponds to the branch port 2120 connected to the delay unit 2300 where the delay module 2320 is located. The magnitude of the optical path difference of the delay module 2320 indicates the corresponding branch port 2120, thus distinguishing different branch ports 2120 of the beam splitting unit 2100. After the first optical signal passes through the beam splitter 2000, it is output as a first optical signal and a second optical signal. Devices connected to the beam splitter 2000 (e.g., OLT or ONU) receive the optical signal and, based on the optical path difference between the first and second optical signals, determine which branch port 2120 of the beam splitter 2000 the signal flows through, thereby associating the optical signal with the corresponding branch port 2120 and determining the network topology.

[0069] In the structure shown in Figure 2, the first region 2210 is the region on the first waveguide 2200 where the delay unit 2300 is away from the branch port 2120, and the second region 2220 is the region on the first waveguide 2200 where the delay unit 2300 is close to the branch port 2120. In this structure, the first optical signal is the uplink transmission signal from the ONU. After the first optical signal passes through the optical splitter 2000, the output is a first optical signal and a second optical signal.

[0070] After receiving the signal, the upstream OLT can determine which branch port 2120 of the optical splitter 2000 the optical signal passes through based on the optical path difference between the first and second optical signals. Then, based on the source address information (indicating the source ONU) in the signal, it can determine the optical splitter 2000 and branch port 2120 connected to that ONU, thereby determining the network topology.

[0071] Optionally, as shown in Figure 3, the first region 2210 is the region on the first waveguide 2200 near the branch port 2120 of the delay unit 2300, and the second region 2220 is the region on the first waveguide 2200 away from the branch port 2120 of the delay unit 2300. In this structure, the first optical signal is the downlink transmission signal from the OLT. After passing through the optical splitter 2000, the first optical signal is output as a first optical signal and a second optical signal.

[0072] After receiving the signal, the downstream ONU can determine which branch port 2120 of the optical splitter 2000 the optical signal passes through based on the optical path difference between the first optical signal and the second optical signal, thereby determining the connection relationship between this ONU and the upstream optical splitter 2000 and branch port 2120, and thus determining the topology of this ONU.

[0073] The beam splitter 2000 provided in this application determines the network topology by connecting delay modules 2320 with different optical path differences on the routes of different branch ports 2120. The beam splitter and combiner module 2310 is used to couple the delay modules 2320 with the corresponding routes of the branch ports 2120 (i.e., the corresponding first waveguides 2200). In this application embodiment, the beam splitter and combiner module 2310 has different structural designs, such as a structure based on Mach zehnder interference (MZI) or a structure based on a micro ring resonator (MRR), which will be described in detail below.

[0074] I. 2310 beam splitting and combining module based on MZI structure.

[0075] As shown in Figure 4, the beam splitting and combining module 2310 includes a splitter 2311 and a combiner 2312. One end of the splitter 2311 is coupled to the first region 2210, and the other end is coupled to the first end of the delay module 2320. One end of the combiner 2312 is coupled to the second region 2220, and the other end is coupled to the second end of the delay module 2320.

[0076] Optionally, the splitter 2311 and combiner 2312 can be the directional couplers shown in Figure 4. The splitter 2311 is actually a segment of waveguide coupled to a first region 2210 of the first waveguide 2200, with one end coupled to the first region 2210 and the other end coupled to the first end of the delay module 2320. Similarly, the combiner 2312 is actually a one-end waveguide coupled to a second region 2220, with one end coupled to the second region 2220 and the other end coupled to the second end of the delay module 2320.

[0077] On the first waveguide 2200, between the first region 2210 and the second region 2220, there is also a target region 2230, a splitter 2311, a delay module 2320, a combiner 2312, and the target region 2230, forming an MZI structure.

[0078] In the embodiments of this application, the structure of MZI has the characteristic of interference superposition after beam splitting, and the delay superposition of optical signals can be realized by further introducing a delay module.

[0079] In this embodiment, the splitter 2311 and combiner 2312 are configured as directional couplers. Directional couplers have a simple and easy-to-implement structure, reducing the difficulty and cost of manufacturing.

[0080] Optionally, the delay module 2320 can be a planar waveguide, optical fiber, free space optical path, etc., and this application does not limit it.

[0081] In this embodiment, splitter 2311 couples the first optical signal from first region 2210 to delay module 2320 and target region 2230, and combiner 2312 couples the second optical signal from delay module 2320 and the first optical signal from target region 2230 to second region 2220. It is worth noting that splitter 2311 and combiner 2312 can also support reverse signal transmission; that is, combiner 2312 can couple the optical signal from second region 2220 to delay module 2320 and target region 2230, and splitter 2311 can couple the optical signals from delay module 2320 and target region 2230 to first region 2210.

[0082] Optionally, the splitter 2311 and combiner 2312 can also be devices independent of the first waveguide 2200. As shown in Figure 5, the splitter 2311 is a 1*2 splitter, including one common port and two branch ports. The common port of the splitter 2311 is connected to the first region 2210, the first branch port of the splitter 2311 is connected to end A of the target region 2230, and the second branch port is coupled to end A of the delay module 2320. The combiner 2312 is a 2*1 combiner, including one common port and two branch ports. The common port of the combiner 2312 is connected to the second region 2220, the third branch port of the combiner 2312 is connected to end B of the target region 2230, and the fourth branch port is coupled to end B of the delay module 2320.

[0083] In this embodiment, the delay module 2320 is used to provide the optical path difference between the first optical signal and the second optical signal. To distinguish the different branch ports 2120 of the beam splitter unit 2100, the optical path differences between the different branches need to be different. Therefore, the absolute value of the optical path difference in the delay module 2320 needs to be larger to improve the distinguishability between the different branches. This requires that the refractive index difference between the waveguide core layer and the cladding of the delay module 2320 be as large as possible compared to the refractive index difference between the waveguide core layer and the cladding on the first waveguide 2200. This embodiment employs several approaches to achieve a larger refractive index difference:

[0084] 1.1 The delay module 2320 and the first waveguide 2200 are located on different chips.

[0085] As shown in Figures 6a and 6b, the beam splitter 2000 can be a chip module structure. The beam splitter 2000 includes a first chip 3100 and a second chip 3200. The refractive index difference between the waveguide core layer and the cladding of the second chip 3200 is greater than the refractive index difference between the waveguide core layer and the cladding of the first chip 3100.

[0086] The beam splitter 2100, the multiple first waveguides 2200, and the splitter 2311 and combiner 2312 of the multiple delay units 2300 are all located on the first chip 3100. The first chip 3100 also includes coupler A and coupler B. Coupler A and coupler B are located on the side of the first chip 3100 facing the second chip 3200. As shown in Figure 6b, coupler A is connected to splitter 2311, and coupler B is connected to combiner 2312.

[0087] The delay modules 2320 of the multiple delay units 2300 are located on the second chip 3200. Among them, the delay modules 2320 of different delay units 2300 can be waveguides of different lengths.

[0088] The second chip 3200 also includes coupler C and coupler D, which are connected sequentially to the delay module 2320 and the fourth coupler D. Coupler C and coupler D are located on the side of the second chip 3200 facing the first chip 3100. As shown in Figure 6b, coupler C and coupler D are respectively connected to the two ends of the delay module 2320.

[0089] The coupler C of the second chip 3200 is used to couple with the coupler A of the first chip 3100, and the coupler D of the second chip 3200 is used to couple with the coupler B of the first chip 3100.

[0090] Coupler A and coupler C can be in-plane vertical couplers or evanescent wave couplers; coupler B and coupler D can be in-plane vertical couplers or evanescent wave couplers.

[0091] In this embodiment, the delay module 2320 and the first waveguide 2200 are disposed on chips with different waveguide core materials, thereby increasing the refractive index difference between the delay module 2320 and the first waveguide 2200 relative to the cladding material. A unit length of delay module 2320 can provide a larger optical path difference (relative to the first waveguide 2200), thereby reducing the length of delay module 2320, reducing the overall volume of beam splitter 2000, and achieving miniaturization of beam splitter 2000.

[0092] In one example, both the first chip 3100 and the second chip 3200 are planar lightwave circuit (PLC) chips. The first chip 3100 is a PLC chip made of quartz or silicon nitride, while the second chip 3200 is a PLC chip made of silicon nitride or single-crystal silicon. Compared to the first chip 3100, the second chip 3200 has a larger refractive index difference, which allows for a smaller volume of the second chip 3200, thereby reducing the overall volume of the beam splitter 2000.

[0093] 1.2 The delay module 2320 and the first waveguide 2200 are located on different layers of the chip.

[0094] As shown in Figure 7, the beam splitter 2000 can be a chip structure, such as a planar lightwave circuit (PLC). The beam splitter 2000 includes a chip 4000, which comprises a first layer 4100 and a second layer 4200. The waveguide materials of the first layer 4100 and the second layer 4200 are different. The refractive index difference between the waveguide core layer and the cladding of the second layer 4200 is greater than the refractive index difference between the waveguide core layer and the cladding of the first layer 4100.

[0095] The beam splitter unit 2100, multiple first waveguides 2200, and multiple delay units 2300, along with their splitter 2311 and combiner 2312, are all located on the first layer 4100. The first layer 4100 also includes coupler A and coupler B. Coupler A and coupler B are located on the side of the first layer 4100 facing the second layer 4200. Coupler A is connected to splitter 2311, and coupler B is connected to combiner 2312.

[0096] Delay modules 2320 of multiple delay units 2300 are located on the second layer 4200. Among them, the delay modules 2320 of different delay units 2300 can be waveguides of different lengths.

[0097] The second chip 3200 also includes coupler C and coupler D, with coupler C, delay module 2320, and fourth coupler D connected in sequence. Coupler C and coupler D are located on the side of the second chip 3200 facing the first chip 3100. Coupler C and coupler B are respectively connected to the two ends of delay module 2320.

[0098] Coupler C of the second layer 4200 is used to couple with coupler A of the first layer 4100, and coupler D of the second layer 4200 is used to couple with coupler B of the first layer 4100.

[0099] Coupler A and coupler C can be in-plane vertical couplers or evanescent wave couplers; coupler B and coupler D can be in-plane vertical couplers or evanescent wave couplers.

[0100] In this embodiment, the delay module 2320 and the first waveguide 2200 are disposed on different layers of the chip, so that the waveguide materials of the different layers are different, which increases the refractive index difference between the delay module 2320 and the first waveguide 2200 relative to the cladding material. The delay module 2320 per unit length can provide a larger optical path difference (relative to the first waveguide 2200), thereby reducing the length of the delay module 2320, reducing the volume of the entire beam splitter 2000, and realizing the miniaturization of the beam splitter 2000.

[0101] In the structures shown in Figures 6a and 7, the cladding material of both the delay module 2320 and the first waveguide 2200 can be SiO2, the waveguide core material of the delay module 2320 can be SiN, and the waveguide core material of the first waveguide 2200 can be SiO2 doped with germanium or silver ions. This material combination is a mature technology in the industry and can achieve low insertion loss optical waveguides.

[0102] 1.3 The first waveguide 2200 is on the chip, while the delay module 2320 is an external waveguide.

[0103] As shown in Figure 8, the beam splitter 2000 can be a chip + optical waveguide structure. The beam splitter 2000 includes a chip 5000. The beam splitting unit 2100, multiple first waveguides 2200, and multiple delay units 2300, along with their respective splitter 2311 and combiner 2312, are all located on the chip 5000. The chip 5000 also includes coupler A and coupler B. Coupler A and coupler B are located on the same surface of the chip 5000. Coupler A is connected to the splitter 2311, and coupler B is connected to the combiner 2312.

[0104] The delay modules 2320 of the multiple delay units 2300 are multiple optical waveguides outside the chip 5000, such as the optical fibers shown in Figure 8. The delay modules 2320 of different delay units 2300 can be optical fibers of different lengths. The two ends of the optical fibers are coupled to coupler A and coupler B on the chip 5000, respectively.

[0105] Coupler A and coupler B can be in-plane vertical couplers or evanescent wave couplers.

[0106] In this embodiment, the first waveguide 2200 is disposed on the chip 5000, and the delay module 2320 is disposed on an optical fiber outside the chip 5000. Since optical fibers have low loss and are flexible, they offer the advantage of low-loss delay.

[0107] In the structures shown in Figures 6a to 8, the splitter 2311 is located on the side closer to the splitting unit 2100, and the combiner 2312 is located on the side farther from the splitting unit 2100. It is worth noting that the splitter 2311 can also be located on the side farther from the splitting unit 2100, and the combiner 2312 can be located on the side closer to the splitting unit 2100; this application does not limit this.

[0108] In the embodiments of this application, in addition to the MZI structure shown in Figures 4 to 8, the beam splitting and combining module can also be based on the micro-ring MRR structure.

[0109] II. 2310 beam splitting and combining module based on MRR structure.

[0110] As shown in Figure 9, the delay module 2320 includes a second waveguide 2321. The beam splitter and combiner module 2310 has a 2*2 structure and includes four ports. Optionally, the beam splitter and combiner module 2310 can be a multimode interference (MMI) coupler or a directional coupler (DC).

[0111] As shown in Figure 9, ports E and F of the beam splitter and combiner module 2310 are connected to the first region 2210 and the second region 2220 of the first waveguide 2200, respectively, and ports G and H are coupled to the two ends of the second waveguide 2321, respectively. The beam splitter and combiner module 2310 and the second waveguide 2321 constitute a micro-ring MRR.

[0112] The beam splitter and combiner module 2310 is used to couple optical signals from ports E and G to ports F and H, and to couple optical signals from ports F and H to ports E and G.

[0113] In this embodiment, the beam splitter / combiner module 2310 and the second waveguide 2321 constitute a micro-ring MRR structure. An optical signal is input from the first region 2210. The beam splitter / combiner module 2310 couples the first optical signal from port E to port H. The first optical signal then passes through the second waveguide 2321 to obtain a second optical signal. The beam splitter / combiner module 2310 couples the second optical signal from port G and the first optical signal from port E to port F. Port F outputs the first and second optical signals to the second region.

[0114] If the intensity of the second optical signal is less than that of the first optical signal, the micro-ring is set to an extremely undercoupled state to reduce the static extinction ratio at the resonant wavelength of the micro-ring, thereby reducing the loss of the optical signal with the resonant wavelength passing through this structure. If the intensity of the second optical signal is greater than that of the first optical signal, the micro-ring is set to an extremely overcoupled state, which can also reduce the static extinction ratio at the resonant wavelength of the micro-ring, thereby reducing the loss of the optical signal with the resonant wavelength passing through this structure.

[0115] In the embodiments of this application, the MRR structure has the characteristics of simple structure and low loss, and can realize a low insertion loss and easy-to-implement delay superposition structure.

[0116] Optionally, the delay module 2320 may also include an attenuation submodule, which is connected to the second waveguide 2321. The attenuation submodule is used to attenuate the resonant signal within the microring when the intensity of the second optical signal is less than the intensity of the first optical signal, so as to more flexibly set the coupling state of the microring.

[0117] Similar to the MZI structure, a large refractive index difference between the delay module 2320 and the first waveguide 2200 can also be achieved in the MRR structure through different structural designs.

[0118] 2.1 The delay module 2320 and the first waveguide 2200 are located on different chips.

[0119] As shown in Figure 10, the beam splitter 2000 can be a chip module structure. The beam splitter 2000 includes a first chip 3100 and a second chip 3200. The refractive index difference between the waveguide core layer and the cladding of the second chip 3200 is greater than the refractive index difference between the waveguide core layer and the cladding of the first chip 3100.

[0120] The beam splitter unit 2100, the multiple first waveguides 2200, and the beam combining module 2310 comprising the multiple delay units 2300 are all located on the first chip 3100. The first chip 3100 also includes couplers E and F. Couplers E and F are located on the side of the first chip 3100 facing the second chip 3200. Couplers E and F are respectively connected to port G and port H of the beam combining module.

[0121] The second waveguides 2321 of the multiple delay units 2300 are located on the second chip 3200. The second waveguides 2321 of different delay units 2300 can be waveguides of different lengths.

[0122] The second chip 3200 also includes coupler G and coupler H, which are connected sequentially to the second waveguide 2321 and the fourth coupler H. Coupler G and coupler H are located on the side of the second chip 3200 facing the first chip 3100. Coupler G and coupler H are respectively connected to both ends of the second waveguide 2321.

[0123] The coupler G of the second chip 3200 is used to couple with the coupler E of the first chip 3100, and the coupler H of the second chip 3200 is used to couple with the coupler F of the first chip 3100.

[0124] Coupler E and coupler G can be in-plane vertical couplers or evanescent wave couplers; coupler F and coupler H can be in-plane vertical couplers or evanescent wave couplers.

[0125] In this embodiment, the second waveguide 2321 and the first waveguide 2200 are disposed on chips with different waveguide core layer materials, thereby increasing the refractive index difference between the second waveguide 2321 and the first waveguide 2200 relative to the cladding material. The second waveguide 2321 per unit length can provide a larger optical path difference (relative to the first waveguide 2200), thereby reducing the length of the second waveguide 2321, reducing the overall volume of the beam splitter 2000, and achieving miniaturization of the beam splitter 2000.

[0126] In one example, both the first chip 3100 and the second chip 3200 are PLC chips. The first chip 3100 is a PLC chip made of quartz or silicon nitride, while the second chip 3200 is a PLC chip made of silicon nitride or single-crystal silicon. Compared to the first chip 3100, the second chip 3200 has a larger refractive index difference, which allows for a smaller volume of the second chip 3200, thereby reducing the overall volume of the beam splitter 2000.

[0127] 2.2 The delay module 2320 and the first waveguide 2200 are located on different layers of the chip.

[0128] As shown in Figure 11, the beam splitter 2000 can be a chip structure, such as a PLC chip. The beam splitter 2000 includes a chip 4000, which comprises a first layer 4100 and a second layer 4200. The waveguide materials of the first layer 4100 and the second layer 4200 are different. The refractive index difference between the waveguide core layer and the cladding of the second layer 4200 is greater than the refractive index difference between the waveguide core layer and the cladding of the first layer 4100.

[0129] The beam splitting unit 2100, the multiple first waveguides 2200, and the beam splitting and combining module 2310 of the multiple delay units 2300 are all located on the first layer 4100. The first layer 4100 also includes couplers E and F. Couplers E and F are located on the side of the first layer 4100 facing the second layer 4200. Coupler E is connected to port G, and coupler H is connected to port H.

[0130] The second waveguides 2321 of multiple delay units 2300 are located on the second layer 4200. The second waveguides 2321 of different delay units 2300 can be waveguides of different lengths.

[0131] The second chip 3200 also includes coupler G and coupler H, which are connected sequentially to the second waveguide 2321 and the fourth coupler H. Coupler G and coupler H are located on the side of the second chip 3200 facing the first chip 3100. Coupler G and coupler H are respectively connected to both ends of the second waveguide 2321.

[0132] The coupler G of the second layer 4200 is used to couple with the coupler E of the first layer 4100, and the coupler H of the second layer 4200 is used to couple with the coupler F of the first layer 4100.

[0133] Coupler E and coupler G can be in-plane vertical couplers or evanescent wave couplers; coupler F and coupler H can be in-plane vertical couplers or evanescent wave couplers.

[0134] In this embodiment, the second waveguide 2321 and the first waveguide 2200 are disposed on different layers of the chip, so that the waveguide materials of the different layers are different, which increases the refractive index difference between the second waveguide 2321 and the first waveguide 2200 relative to the cladding material. The second waveguide 2321 per unit length can provide a larger optical path difference (relative to the first waveguide 2200), thereby reducing the length of the second waveguide 2321, reducing the volume of the entire beam splitter 2000, and realizing the miniaturization of the beam splitter 2000.

[0135] In the structures shown in Figures 10 and 11, the cladding material of both the second waveguide 2321 and the first waveguide 2200 can be SiO2, the waveguide core material of the delay module 2320 can be SiN, and the waveguide core material of the first waveguide 2200 can be SiO2 doped with germanium or silver ions. This material combination is a mature technology in the industry and can achieve low insertion loss optical waveguides.

[0136] 2.3 The first waveguide 2200 is on the chip, while the delay module 2320 is an external waveguide.

[0137] As shown in Figure 12, the beam splitter 2000 can be a chip + optical waveguide structure. The beam splitter 2000 includes a chip 5000. A beam-splitting and combining module 2310, comprising a beam-splitting unit 2100, multiple first waveguides 2200, and multiple delay units 2300, is located on the chip 5000. The chip 5000 also includes couplers E and F. Couplers E and F are located on the same surface of the chip 5000. Coupler E is connected to port G, and coupler F is connected to port H.

[0138] The second waveguides 2321 of the multiple delay units 2300 are multiple optical waveguides outside the chip 5000, such as the optical fibers shown in Figure 12. The second waveguides 2321 of different delay units 2300 can be optical fibers of different lengths. The two ends of the optical fibers are coupled to couplers E and F on the chip 5000, respectively.

[0139] Coupler E and coupler F can be in-plane vertical couplers or evanescent wave couplers.

[0140] In this embodiment, the first waveguide 2200 is disposed on the chip 5000, and the second waveguide 2321 is disposed as an optical fiber outside the chip 5000. Since optical fibers have low loss and are flexible, they have the advantage of low loss delay.

[0141] The above embodiments all use a PLC chip as a base to illustrate the structure of the beam splitter 2000. It is worth noting that the beam splitter 2000 can also be implemented based on a fused biconical taper (FBT) structure. For example, the multiple first waveguides 2200 connected to the multiple branch ports 2120 of the beam splitting unit 2100 are multiple optical fibers. The beam splitter 2000 structure can be obtained by fusing optical fibers (delay modules 2320) of different lengths onto the multiple first waveguides 2200 using the FBT process.

[0142] This application also includes an optical fiber distribution network (ODN). The ODN includes one or more optical splitters 2000. The optical splitter 2000 is the optical splitter 2000 described in any of the embodiments shown in Figures 2 to 12 above.

[0143] Optionally, if, as shown in Figure 13, the multiple optical splitters 2000 of the ODN include multiple stages of optical splitters (e.g., the first-stage optical splitter in Figure 13, and multiple second-stage optical splitters connected to the first-stage optical splitter), then the optical path difference of the delay modules 2320 in different stages of the optical splitter is different.

[0144] In this embodiment of the application, the optical path difference of different levels of optical splitters is made different. Then, the receiving end of the optical signal (e.g., OLT or ONU) can identify the optical path difference experienced by the signal in the multi-level optical splitters it passes through based on the difference between the optical path differences between different levels of optical splitters. This allows the branch ports of each level of optical splitter that the optical signal passes through to be determined, and the network topology to be determined in the network of multi-level optical splitters.

[0145] For example, in Figure 13, the optical path differences x of the delay modules 2320 on the three branch ports of the first-stage optical splitter are 11, 12, and 13 from top to bottom; the optical path differences y1 of the delay modules 2320 on the two branch ports of the second-stage optical splitter A are 1 and 2 from top to bottom. The optical signal sent by the ONU connected to the second-stage optical splitter A is transmitted to the OLT via the second-stage optical splitter A and the first branch port of the second-stage optical splitter A. The OLT can identify the optical path difference 11 and the optical path difference 1 from the received signal, thereby determining that the ONU is connected to the first branch port of the second-stage optical splitter A and the first branch port of the second-stage optical splitter A.

[0146] It is worth noting that, for beam splitters of the same level, the embodiments of this application do not limit whether their optical path differences are the same. For example, in Figure 13, the optical path differences y1-y3 of the second-level beam splitter AC can be the same or different.

[0147] Applying the above-mentioned ODN to the PON network shown in Figure 1 results in the Passive Optical Network (PON) provided in this embodiment of the application.

[0148] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0149] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0150] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0151] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0152] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A beam splitter, characterized in that, It includes a beam splitter unit, multiple first waveguides, and multiple delay units, wherein the beam splitter unit includes a common port and multiple branch ports; The plurality of first waveguides are connected to the plurality of branch ports one by one, and the plurality of delay units are connected to the plurality of first waveguides one by one; Any of the plurality of delay units includes a beam splitting and combining module and a delay module; The beam splitting and combining module is coupled to the corresponding first waveguide. The beam splitting and combining module is used to separate the second optical signal from the first optical signal in the first region of the first waveguide, and to couple the second optical signal through the delay module to the second region of the first waveguide. The delay module is used to provide the optical path difference between the first optical signal and the second optical signal. Among the multiple delay units, the delay modules of different delay units are used to provide different optical path differences.

2. The beam splitter according to claim 1, characterized in that, The beam splitting and combining module includes a splitter and a combiner; One end of the splitter is coupled to the first region, and the other end is coupled to the first end of the delay module; One end of the combiner is coupled to the second region, and the other end is coupled to the second end of the delay module.

3. The beam splitter according to claim 1, characterized in that, The beam splitter and combiner module includes a splitter and a combiner, and the first waveguide includes a target region, which is located between the first region and the second region. The common port of the splitter is connected to the first region of the first waveguide, the first branch port of the splitter is connected to the first end of the target region, and the second branch port is coupled to the third end of the delay module. The common port of the combiner is connected to the second region of the first waveguide, the third branch port of the combiner is connected to the second end of the target region, and the fourth branch port is coupled to the fourth end of the delay module.

4. The beam splitter according to claim 2 or 3, characterized in that, The beam splitter includes a first chip and a second chip; The beam splitting unit, the plurality of first waveguides, and the splitters and combiners of the plurality of delay units are located on the first chip, and the first chip further includes a first coupler and a second coupler; The delay modules of the plurality of delay units are located on the second chip. The second chip also includes a third coupler and a fourth coupler, and the third coupler, the delay modules, and the fourth coupler are connected in sequence. The splitter is connected to the first coupler, and the combiner is connected to the second coupler; The third coupler of the second chip is used to couple with the first coupler of the first chip, and the fourth coupler of the second chip is used to couple with the second coupler of the first chip.

5. The beam splitter according to claim 2 or 3, characterized in that, The beam splitter is a planar optical waveguide PLC chip; The beam splitting unit, the plurality of first waveguides, and the splitters and combiners of the plurality of delay units are located on the first layer of the PLC chip, and the first layer further includes a fifth coupler and a sixth coupler; The delay modules of the multiple delay units are located on the second layer of the PLC chip. The waveguide materials of the first layer and the second layer are different. The second layer also includes a seventh coupler and an eighth coupler. The seventh coupler, the delay module and the eighth coupler are connected in sequence. The splitter is connected to the fifth coupler, and the combiner is connected to the sixth coupler; The seventh coupler of the second layer is used to couple with the fifth coupler of the first layer, and the eighth coupler of the second layer is used to couple with the sixth coupler of the first layer.

6. The beam splitter according to claim 2 or 3, characterized in that, The beam splitter includes a chip, and the splitter and combiner of the beam splitting unit, the plurality of first waveguides, and the delay unit are located on the chip. The chip also includes a ninth coupler and a tenth coupler. The splitter is connected to the ninth coupler, and the combiner is connected to the tenth coupler; The delay module is an optical fiber, and the two ends of the optical fiber are coupled to the ninth coupler and the tenth coupler on the chip, respectively.

7. The beam splitter according to claim 1, characterized in that, The delay module includes a second waveguide; The first port and the second port of the beam splitting and combining module are respectively connected to the first region and the second region of the first waveguide, and the third port and the fourth port are respectively coupled to the two ends of the second waveguide. The beam splitter and combiner module is used to couple the optical signals from the first port and the third port to the second port and the fourth port.

8. The beam splitter according to claim 7, characterized in that, The beam splitter includes a first chip and a second chip; The beam splitting unit, the plurality of first waveguides, and the beam splitting and combining module of the plurality of delay units are located on the first chip, and the first chip further includes an eleventh coupler and a twelfth coupler; The second waveguide of the plurality of delay units is located on the second chip, and the second chip further includes a thirteenth coupler and a fourteenth coupler, wherein the thirteenth coupler, the second waveguide and the fourteenth coupler are connected in sequence; The third and fourth ports of the beam splitting and combining module are respectively connected to the eleventh coupler and the twelfth coupler; The thirteenth coupler of the second chip is used to couple with the eleventh coupler of the first chip, and the fourteenth coupler of the second chip is used to couple with the twelfth coupler of the first chip.

9. The beam splitter according to claim 7, characterized in that, The beam splitter is a planar optical waveguide PLC chip; The beam splitting unit, the plurality of first waveguides, and the beam splitting and combining module of the plurality of delay units are located on the first layer of the PLC chip, and the first layer further includes a fifteenth coupler and a sixteenth coupler; The delay modules of the multiple delay units are located on the second layer of the PLC chip. The waveguide materials of the first layer and the second layer are different. The second layer also includes a seventeenth coupler and an eighteenth coupler. The seventeenth coupler, the delay module and the eighteenth coupler are connected in sequence. The third and fourth ports of the beam splitting and combining module are respectively connected to the fifteenth and sixteenth couplers; The seventeenth coupler of the second layer is used to couple with the fifteenth coupler of the first layer, and the eighteenth coupler of the second layer is used to couple with the sixteenth coupler of the first layer.

10. The beam splitter according to claim 7, characterized in that, The beam splitter includes a chip, and the beam splitting unit, the plurality of first waveguides, and the beam splitting and combining module of the plurality of delay units are located on the chip. The chip also includes a nineteenth coupler and a twentieth coupler. The third and fourth ports of the beam splitting and combining module are respectively connected to the nineteenth coupler and the twentieth coupler; The delay module is an optical fiber, and the two ends of the optical fiber are coupled to the nineteenth coupler and the twentieth coupler on the chip, respectively.

11. The beam splitter according to any one of claims 7 to 10, characterized in that, The beam splitter and combiner module and the second waveguide form a micro-ring: If the intensity of the second optical signal is less than the intensity of the first optical signal, the micro-ring is set to an extremely undercoupled state. If the light intensity of the second optical signal is greater than that of the first optical signal, then the micro-ring is set to an overcoupled state.

12. The beam splitter according to claim 11, characterized in that, The delay module also includes an attenuation submodule, which is used to attenuate the resonant signal in the micro-ring when the light intensity of the second optical signal is less than that of the first optical signal.

13. The beam splitter according to any one of claims 1 to 12, characterized in that, Among the multiple delay units, the delay module includes a second waveguide, and the length of the second waveguide of different delay units is different.

14. The beam splitter according to claim 4 or 8, characterized in that, The beam splitter is a planar optical waveguide PLC chip; The refractive index difference between the waveguide core layer and the cladding of the second chip is greater than the refractive index difference between the waveguide core layer and the cladding of the first chip.

15. The beam splitter according to claim 5 or 9, characterized in that, The refractive index difference between the waveguide core layer and the cladding layer in the second layer is greater than the refractive index difference between the waveguide core layer and the cladding layer in the first layer.

16. The beam splitter according to claim 14 or 15, characterized in that, The waveguide core material of the delay module is SiN, and the waveguide core material of the plurality of first waveguides is SiO2 doped with germanium ions or silver ions.

17. An optical fiber distributed network (ODN), characterized in that, It includes one or more beam splitters, wherein the beam splitter is any one of claims 1 to 16.

18. The ODN according to claim 17, characterized in that, The multiple beam splitters include multi-stage beam splitters, and the optical path difference of the delay modules in different stages of the beam splitters is different.

19. A passive optical network (PON), characterized in that, Includes the ODN as described in claim 17 or 18.

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