WO2022001230A1 - 分光器、odn、识别onu所在光链路的方法、olt、onu和pon系统 - Google Patents

分光器、odn、识别onu所在光链路的方法、olt、onu和pon系统 Download PDF

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WO2022001230A1
WO2022001230A1 PCT/CN2021/082842 CN2021082842W WO2022001230A1 WO 2022001230 A1 WO2022001230 A1 WO 2022001230A1 CN 2021082842 W CN2021082842 W CN 2021082842W WO 2022001230 A1 WO2022001230 A1 WO 2022001230A1
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optical
light
wavelength
olt
onu
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PCT/CN2021/082842
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English (en)
French (fr)
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董小龙
董振华
董英华
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华为技术有限公司
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q11/0067—Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0795—Performance monitoring; Measurement of transmission parameters
    • H04B10/07955—Monitoring or measuring power
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0795—Performance monitoring; Measurement of transmission parameters
    • H04B10/07957—Monitoring or measuring wavelength
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/40—Transceivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0079—Operation or maintenance aspects
    • H04Q2011/0083—Testing; Monitoring

Definitions

  • the present invention relates to the field of optical communication, and more particularly, to an optical splitter, an ODN, a method for identifying an optical link where an ONU is located in a PON system, an OLT, an ONU and a PON system.
  • a passive optical network (PON) system it usually includes an optical line termination (OLT), an optical distribution network (ODN) and an optical network unit (ONU), ODN Provide optical transmission physical channel between OLT and ONU.
  • OLT optical line termination
  • ODN optical distribution network
  • ONU optical network unit
  • ODN generally includes optical distribution frame (Optical Distribution Frame, ODF), optical cable splice box (also known as splitting and splicing closure (SSC)), optical cable junction box (also known as fiber distribution terminal (fiber distribution terminal, FDT)), fiber distribution box (also known as fiber access terminal (FAT)), fiber terminal box (also known as access terminal box (ATB)), etc.
  • FDT may include Optical splitter 1
  • FAT may include optical splitter 2.
  • the optical signal from the OLT is split through the optical splitter 1 in the ODF, SSC, and FDT in sequence, split by the optical splitter 2 in the FAT, and then reaches the ONU through the ATB, that is, the optical signal from the OLT passes through the OLT and the ONU.
  • the optical link between them is transmitted to the ONU.
  • the optical splitter 1 divides the received optical signal power equally, one of the branches is transmitted to the optical splitter 2, and then the optical splitter 2 divides the received optical signal power equally, and each branch is transmitted to the connected ONU respectively.
  • the output end of the last stage optical splitter in the ODN is used as the output port of the ODN, and the ONU is connected to the output port of the ODN.
  • the operator or the central office cannot know which output port of the ODN each ONU is specifically connected to, that is, which optical link each ONU is located on, or the installer needs to go to the site. Only by recording, can each ONU be specifically connected to which ODN output port (that is, which optical link the ONU is specifically located on), which is not only prone to errors, but also inefficient and labor-intensive.
  • the present application provides an optical splitter, an ODN, a method for identifying an optical link where an ONU is located in a PON system, an OLT, an ONU and a PON system, aiming to quickly and accurately detect the optical link where the ONU is located, and improve the accuracy of the optical link. Efficiency of the optical link where the ONU is located.
  • a light splitter in a first aspect, includes: a light incident segment and N light exit segments, where N is an integer greater than or equal to 2; and each light exit segment in at least N-1 light exit segments is provided with At least one optical filter structure, each optical filter structure filters a light signal of a wavelength with a specific transmittance; any two light-emitting sections provided with the optical filter structure meet at least one of the following conditions 1 and 2: Condition 1: The filtered at least one wavelength is different; Condition 2: The transmittance to the optical signal of at least one wavelength is different. Wherein, there are at least two of the light-emitting segments that satisfy the condition 2.
  • the optical splitter When the optical splitter is applied to the ODN of the PON, since the wavelengths of the optical signals filtered between the two light-emitting sections can be different, or the transmittance of the same optical signal is different, it can not only be distinguished by the wavelength of the filtered optical signals The optical segment can also be distinguished by combining the transmittance of the same optical signal. Therefore, when the OLT side sends test light to detect the optical link where the ONU is located, it can greatly reduce the types of test light, save wavelength resources, and reduce The wavelength scanning range of the test light of the small OLT reduces the manufacturing difficulty and cost of the device that transmits the test light of the OLT, and is easy to implement.
  • At least one of the light exit segments is provided with M optical filter structures, each of which is The light exit section filters optical signals of M wavelengths, where M is an integer greater than or equal to 2.
  • a third possible implementation manner at most one of the light filtering structures is provided on each of the light exit segments.
  • Each light-emitting section is distinguished by the number of light filtering structures, the filtered wavelengths, and the corresponding transmittance. Various combinations further reduce the types of test light and expand the transmittance interval.
  • the optical splitter is an equal splitter or an unequal splitter.
  • the N light emitting sections of the unequal splitter include 1 unequal ratio light section and N-1 equal ratio light sections, and the unequal ratio light section can be The optical filter structure is not set.
  • one of the optical filtering structures may also be provided on the unequal ratio light output segment, or at least two optical filtering structures may also be provided.
  • the difference between the unequal-ratio light-emitting section and any of the equal-ratio light-emitting sections satisfies that there is no optical filtering structure capable of filtering the same wavelength.
  • Multi-level optical splitters can identify the optical link where the ONU is located.
  • the optical splitter may be a planar optical waveguide PLC splitter, and the PLC splitter includes an optical input end fiber, N optical exit fibers, and a planar optical waveguide; the planar optical waveguide includes an input optical fiber.
  • each of the optical outgoing segments includes the intermediate branch A waveguide, a pair of the light-exiting waveguide ends and the light-exiting end fibers connected to each other.
  • the light filtering structure is disposed on at least one of the intermediate branch waveguide, the light exit waveguide end, and the light exit end fiber.
  • the optical fiber at the light exit end includes a ribbon fiber, and the optical filter structure is arranged on the ribbon fiber, which is more convenient to manufacture the optical filter structure, and the preparation is simple.
  • the grating can be etched centrally, thereby reducing the cost.
  • the optical splitter further includes a fixed box body, and the fixed box body is used for encapsulating and fixing the part of the tape fiber provided with the light filtering structure inside the fixed box body.
  • the fixed box can straighten and fix the part with the grating on the tape fiber as much as possible, and set it in the air, so that the grating can minimize the influence of external environmental factors, such as the influence of the stress generated by artificial pulling and wind blowing on the grating period. , to protect the grating
  • the optical splitter can also be a fused taper optical splitter, the fused taper optical splitter includes an optical input end fiber, a coupling region optical fiber and N light exit end fibers, and the optical filtering structure is arranged on the light exit end fibers.
  • the light filtering structure is a grating, or the light filtering structure is a filter film.
  • an optical distribution network ODN includes a primary optical splitter and a secondary optical splitter; the primary optical splitter is the optical splitter according to any one of the first aspect above, and the first optical splitter
  • the light incident section of the first-level optical splitter is called the first light-incident section, and the light-exit section of the first-level optical splitter is called the first light-exit section;
  • the second-level optical splitter is the optical splitter described in any one of the first aspects above , and the incident light section of the secondary beam splitter is called the second incident light section, and the light exit section of the secondary beam splitter is called the second light exit section; a first light exit section and a second light entrance section Optical segment connection; the first light incident segment, a pair of mutually connected first light exit segments and second light incident segments, and one of the second light exit segments form an optical link; any two The optical link satisfies at least one of the following conditions 1 and 2: condition 1, at least one of the wavelengths to be
  • the wavelengths of the filtered optical signals between the two light-emitting segments can be different, or the transmittance of the same optical signal can be different, not only the wavelengths of the filtered optical signals can be used to distinguish the optical segments, but also the same optical signal can be combined. Therefore, when the test light is sent on the OLT side to detect the optical link where the ONU is located, the types of test light can be greatly reduced, wavelength resources can be saved, and the wavelength scanning range of the OLT test light can be reduced. The manufacturing difficulty and cost of the device that transmits the test light are easy to realize.
  • the first-level optical splitter and the second-level optical splitter are equal splitters, and there are multiple second-level optical splitters, and Each of the secondary optical splitters is the same optical splitter, and any primary optical splitter and any secondary optical splitter are different optical splitters.
  • the secondary optical splitter is the same optical splitter, which can greatly reduce the types of optical splitters in the ODN. One is to reduce the production cost of the manufacturer, and the other is to facilitate the installation of the construction personnel, and it is not easy to make mistakes during the installation process.
  • any one of the first light exit segments and any of the second light exit segments satisfies: there is no filter capable of filtering the light filtering structure of the same wavelength. Therefore, for any optical link, there is only one optical filter structure to filter the optical signal of the same wavelength with a specific transmittance, and the optical splitters of different levels will not superimpose the filtering of the optical signal of the same wavelength.
  • Optical splitters do not affect each other when filtering optical signals, and multiple levels of optical splitters can be set in the ODN, such as four or more levels of optical splitters, etc., all of which can identify the optical link where the ONU is located.
  • both the first-level optical splitter and the second-level optical splitter are unequal splitters; so
  • the light emitting section of the unequal splitter includes 1 unequal ratio light section and N-1 equal ratio light sections; Describe the incoming optical segment connection.
  • the primary optical splitter and the secondary optical splitter are the same unequal splitter. Therefore, only one type of unequal splitter can be included in the ODN.
  • the fewer types of optical splitters in the ODN the more favorable it is to reduce the cost, and it is not easy to make mistakes in the installation process.
  • a method for identifying an optical link of an optical network unit ONU in a passive optical network PON system including: the OLT sends down test light of Q wavelengths, wherein Q is an integer greater than or equal to 1,
  • the first optical link between the OLT and the first ONU has a specific transmittance to the test light of at least one wavelength;
  • the OLT receives the feedback information fed back by the first ONU, and the feedback information is used to indicate the received power value of the test light;
  • the OLT determines the transmittance according to the received power value of the test light of at least one wavelength;
  • the OLT determines the transmittance according to the relationship between the optical link and the wavelength and transmittance, and the At least one wavelength and the determined transmittance determine that the first ONU is located in the first optical link.
  • the wavelength and transmittance are combined. Therefore, when the OLT side sends the test light to detect the optical link where the ONU is located, the transmission of the test light can be greatly reduced. It saves wavelength resources, reduces the wavelength scanning range of the test light of the OLT, reduces the manufacturing difficulty and cost of the device for transmitting the test light of the OLT, and is easy to implement.
  • Q is greater than or equal to 2
  • the OLT sending down the test light of the Q wavelengths includes: the OLT sequentially sending down the Q wavelengths in time sequence. Test light; wherein, after the OLT sends the test light of one wavelength in the downlink each time, it waits to receive the feedback information fed back by the first ONU; after receiving the feedback information, the OLT downlinks again The test light of the next wavelength is sent.
  • This method does not need to occupy additional information to indicate the wavelength, and the wavelength can be judged directly according to the time sequence. No additional changes to the message format are required.
  • each of the Q wavelengths of test light sent downstream by the OLT carries a label, wherein any two wavelengths of the test light carry a label.
  • the labels carried by the test light are different; the feedback information is used to indicate the received power value of the test light and the label carried in the test light; the method further includes: the OLT determines the label according to the label. The wavelength of the test light corresponding to the received power value.
  • the method further includes: the OLT determines, by the OLT, a maximum value among multiple received power values as a reference reception power value; the determining of the transmittance by the OLT according to the received power value of the test light of at least one wavelength includes: the OLT determining the transmittance according to the received power value of the test light of the at least one wavelength and the reference received power value transmittance of the test light of the at least one wavelength in the first optical link.
  • the method further includes: the OLT sends a service optical signal downlink; the OLT receives service optical information fed back by the first ONU, where the service optical information is used to indicate service optical received power of the service optical signal value; the OLT determines the transmittance of the test light of the at least one wavelength on the first optical link according to the received power value of the test light of the at least one wavelength and the received power value of the service light.
  • the method further includes: the OLT sending optical link information, where the optical link information is used to indicate the first optical link.
  • the optical link information includes identification information of each of the optical splitters in the various levels of optical splitters, and identification information of each of the ports located on the first optical link.
  • the PON system includes an optical distribution network ODN, and the ODN is the above ODN.
  • a fourth aspect provides a method for identifying an optical link where an optical network unit ONU in a passive optical network PON system is located, comprising: the optical network unit ONU receiving test light of Q wavelengths sent by the optical line terminal OLT, wherein Q Be an integer greater than or equal to 1, the first optical link between the OLT and the ONU has a specific transmittance to the test light of at least one wavelength; the ONU determines the The received power value of the test light; the ONU sends feedback information to the OLT, where the feedback information is used to indicate the received power value of the test light. Since the first optical link between the OLT and the ONU transmits the optical signal, the wavelength and transmittance are combined.
  • the types of test light can be greatly reduced.
  • the wavelength resource is saved, the wavelength scanning range of the test light of the OLT is reduced, the manufacturing difficulty and cost of the device for transmitting the test light of the OLT are reduced, and it is easy to realize.
  • Q is greater than or equal to 2
  • the ONU receiving the test light of the Q wavelengths sent by the OLT includes: the ONU sequentially receiving the Q wavelengths sent by the OLT according to the time sequence wavelength of test light; wherein, after the ONU receives the test light of one wavelength, it sends feedback information to the OLT, where the feedback information is used to indicate the received power of the test light of the one wavelength and after sending the feedback information, the ONU receives the test light of the next wavelength.
  • This method does not need to occupy additional information to indicate the wavelength, and the wavelength can be judged directly according to the time sequence. No additional changes to the message format are required.
  • each of the Q wavelengths of test light received by the ONU carries a label, wherein the test light of any two wavelengths The labels carried by the light are different;
  • the ONU sending the determined received power value of the test light of each wavelength to the OLT includes: the ONU sending feedback information to the OLT, and the feedback information is used for Indicates the received power value of the test light and the tag carried in the test light.
  • the OLT sending test light and the ONU sending feedback information are not limited by time sequence, and the implementation is more flexible.
  • the method further includes: the ONU receiving a service optical signal sent by the OLT; the ONU determining the service optical signal Service optical received power value of the optical signal; the ONU sends service optical information to the OLT, where the service optical information is used to indicate the service optical received power value of the service optical signal.
  • a fifth aspect provides an OLT, the OLT includes a transceiver and a processor; the transceiver is used for downlink sending test light of Q wavelengths, where Q is an integer greater than or equal to 1, and the OLT and the first
  • the first optical link between an ONU has a specific transmittance for the test light of at least one wavelength
  • the transceiver is further configured to receive feedback information fed back by the first ONU, and the feedback information is used for Indicate the received power value of the test light
  • the processor is used to determine the transmittance according to the received power value of the test light of at least one wavelength
  • the processor is also used to determine the transmittance according to the optical link and the wavelength and transmittance.
  • the at least one wavelength and the determined transmittance determine that the first ONU is located on the first optical link. Since the first optical link between the OLT and the first ONU transmits the optical signal, the wavelength and transmittance are combined. Therefore, when the OLT side sends the test light to detect the optical link where the ONU is located, the transmission of the test light can be greatly reduced. It saves wavelength resources, reduces the wavelength scanning range of the test light of the OLT, reduces the manufacturing difficulty and cost of the device for transmitting the test light of the OLT, and is easy to implement.
  • the transceiver when Q is greater than or equal to 2, the transceiver sends down the test light of the Q wavelengths in sequence in sequence; wherein, the transceiver downlinks each time After sending the test light of one wavelength, wait to receive the feedback information fed back by the first ONU; after receiving the feedback information, the transceiver sends the test light of the next wavelength downlink .
  • This method does not need to occupy additional information to indicate the wavelength, and the wavelength can be judged directly according to the time sequence. No additional changes to the message format are required.
  • the transceiver is further configured to send optical link information, where the optical link information is used to indicate the the first optical link, the optical link information includes the identification information of each of the optical splitters in the optical splitters at all levels, and the identification information of each of the ports located on the first optical link .
  • a sixth aspect provides an ONU, the ONU includes a transceiver and a processor; the transceiver is used to receive test light of Q wavelengths sent by the optical line terminal OLT, wherein Q is an integer greater than or equal to 1, so The first optical link between the OLT and the ONU has a specific transmittance to the test light of at least one wavelength; the processor is used to determine the received power of the test light of each wavelength received value; the transceiver is further configured to send feedback information to the OLT, where the feedback information is used to indicate the received power value of the test light. Since the first optical link between the OLT and the ONU transmits the optical signal, the wavelength and transmittance are combined.
  • the types of test light can be greatly reduced.
  • the wavelength resource is saved, the wavelength scanning range of the test light of the OLT is reduced, the manufacturing difficulty and cost of the device for transmitting the test light of the OLT are reduced, and it is easy to realize.
  • the transceiver is further configured to receive the service optical signal sent by the OLT; the processor is further configured to use for determining the service optical received power value of the service optical signal; the transceiver is further configured to send service optical information to the OLT, where the service optical information is used to indicate the service optical received power value of the service optical signal.
  • a passive optical network PON system includes the above-mentioned optical line terminal OLT, the above-mentioned optical network unit ONU, and the above-mentioned optical distribution network ODN.
  • Another aspect of the present application provides a computer-readable storage medium, where the computer-readable storage medium stores corresponding computer software instructions used by the OLT described in the third aspect and any implementation manner thereof. When it runs on a computer, it causes the computer to execute the corresponding method steps described in the above aspects.
  • Figure 1 is a schematic structural diagram of a PLC optical splitter in an embodiment of the present invention.
  • Figure 1 (2) is a schematic structural diagram of a PLC optical splitter in another embodiment of the present invention.
  • Fig. 1 (3) is the structural representation of PLC optical splitter in another embodiment of the present invention.
  • Fig. 1 is the structural representation of PLC optical splitter in still another embodiment of the present invention.
  • FIG. 2 is a schematic diagram of the fixing of the fixing box body and the tape fiber according to an embodiment of the present invention
  • FIG. 3(1) is a schematic structural diagram of an FBT optical splitter in an embodiment of the present invention.
  • Figure 3 (2) is a schematic structural diagram of an FBT optical splitter in another embodiment of the present invention.
  • FIG. 4 is an exemplary diagram of an optical filter structure filtering an optical signal of one wavelength with a specific transmittance in the present invention
  • FIG. 5 is a schematic structural diagram of an unequal splitter in an embodiment of the present invention.
  • Fig. 6 is an example diagram of an ODN-implementation scheme
  • FIG. 7 is a schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 8 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 9 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 10 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 11 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 12 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 13 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 14 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 15 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • 16 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 17 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • FIG. 18 is another schematic diagram of an ODN in a PON system according to an embodiment of the present invention.
  • 19 is a schematic flowchart of a method for identifying an optical link where an ONU is located in a PON system according to an embodiment of the present invention
  • FIG. 20 is a schematic structural diagram of an OLT in an embodiment of the present invention.
  • FIG. 21 is a schematic structural diagram of an ONU in an embodiment of the present invention.
  • An embodiment of the present application provides an optical splitter, and the optical splitter may also be referred to as an optical splitter module, an optical splitter, or the like.
  • the optical splitter is used to divide one optical signal into multiple optical signals.
  • the optical splitter can be used in scenarios where light splitting is required, such as in an optical distribution network (ODN). Take the optical splitter used in ODN as an example, the optical splitter can be set in the optical splitting device. .
  • ODN optical distribution network
  • FIG. 1(1), FIG. 1(2), FIG. 1(3), FIG. 1(4), FIG. 3(1) and FIG. 3(2), FIG. 1(1) to FIG. 1(4) is a schematic structural diagram of a planar optical waveguide beam splitter in an embodiment of the present invention
  • FIG. 3(1) and FIG. 3(2) are schematic structural diagrams of a fused taper beam splitter in an embodiment of the present invention.
  • the optical splitter includes an incident light segment 100 and N light outgoing segments 200 , where N is an integer greater than or equal to 2.
  • the optical signal enters through the light incoming segment 100 and is output from the N light outgoing segments 200 .
  • At least one light filter structure 210 is provided on each light exit segment 200 of the at least N-1 light exit segments 200, and each light filter structure filters an optical signal of one wavelength with a specific transmittance, which can also be understood as an optical filter structure.
  • 210 filters a central wavelength optical signal with a specific transmittance. It can be understood that, the optical filter structure 210 filters an optical signal in a wavelength range, and the optical signal in this wavelength has a center wavelength, and the transmittance reaches a minimum value at the center wavelength.
  • FIG. 4 is a schematic diagram of the optical filter structure 210 filtering an optical signal of one wavelength with a specific transmittance, where the abscissa represents the wavelength and the ordinate represents the transmittance. Assuming that the transmittance at the central wavelength 1 reaches a minimum value of 20% in FIG. 4 , it can be understood that the optical filter structure 210 filters the optical signal of wavelength 1 (or central wavelength 1 ) with a specific transmittance.
  • the above-mentioned light filtering structure 210 filters an optical signal of one wavelength with a specific transmittance, wherein the specific transmittance may have a minimum value of 0 and a maximum value of less than 100%.
  • any two light emitting sections 200 provided with the optical filter structure 210 at least satisfy at least one of the following conditions 1 and 2: condition 1, at least one wavelength to be filtered is different; condition 2, for optical signals of at least one wavelength different transmittances. It can be understood that, between any two light exit segments 200 provided with the optical filter structure 210 , only condition 1 may be satisfied, or only condition 2 may be satisfied, or both conditions 1 and 2 may be satisfied simultaneously.
  • Condition 2 can be understood as different transmittances for optical signals of the same wavelength. For example, if there is a light-emitting section 200 with a transmittance of 30% for the optical signal of wavelength 1, and there is another light-emitting section 200 with a transmittance of 70% for the optical signal with wavelength 1, it is considered that the two light-emitting sections 200 satisfy the condition 2 .
  • the light incident section 100 is an optical path in an optical splitter for transmitting the above-mentioned one optical signal. Inside the optical splitter, one optical signal is divided into N optical signals, and the light exit section 200 is the optical path after the light entrance section 100 .
  • the number of light incident segments 100 of the optical splitter may be one, or at least two. Taking two light incident sections 100 as an example, when the optical splitter is used in an ODN network, one of the light incident sections 100 is connected to the main path optical fiber, and the other light incident section 100 is connected to the backup optical fiber.
  • the optical splitter is a planar lightwave circuit (PLC) optical splitter, and the PLC optical splitter includes an optical input end fiber 110 and N light output fibers. end fiber 221, and planar optical waveguide 230.
  • the PLC optical splitter may further include a substrate 240 on which the planar optical waveguide 230 is disposed.
  • the planar optical waveguide 230 includes an incoming optical waveguide end 120, N outgoing waveguide ends 231, and an intermediate branch waveguide 232 connected between the incoming optical waveguide end and the N optical outgoing waveguide ends 231.
  • the light incident end fiber 110 is connected to the light incident waveguide end.
  • the N light-exiting end fibers 221 are connected to the N light-exiting waveguide ends 231 in a one-to-one correspondence.
  • the PLC optical splitter may further include an adhesive 250 for connecting the optical fiber 110 at the incoming end to the optical waveguide end, and connecting the optical fiber 221 at the outgoing end with the optical waveguide end 231 .
  • the above-mentioned light incident section 100 includes the light incident end optical fiber 110 and the light incident waveguide end.
  • Each light exit section 200 includes a middle branch waveguide 232 , a pair of light exit waveguide ends 231 and a light exit fiber 221 connected to each other. It can be understood that each light exit section 200 includes a part of the intermediate branch waveguide 232.
  • the intermediate branch waveguide 232 in the first light exit section 200 shown in FIG. 1(1) includes M21 and M31; the second light exit section The intermediate branch waveguide 232 in 200 includes M21, M32.
  • the ends of the N light-exiting end fibers 221 form the fiber array 220, the substrate 240 and the waveguide form a beam splitter chip, and the beam splitter chip and the fiber array 220 are bonded together by the adhesive 250, and make N
  • the light-outgoing waveguide ends 231 are connected to the N light-outgoing end fibers 221 in a one-to-one correspondence.
  • the optical splitter is a Fused biconical taper (FBT) optical splitter
  • the FBT optical splitter includes an optical input end fiber 110, a coupling region Optical fiber 270 and N light-exiting end optical fibers 221 .
  • the FBT optical splitter bundles two or more optical fibers together, and then melts and stretches them on the taper machine, and monitors the change of the splitting ratio in real time. After the splitting ratio reaches the requirements, the melting and stretching is ended, and one optical fiber is retained at the input end.
  • the remaining optical fibers are cut off, and the remaining optical fiber is used as the optical fiber 110 at the optical input end, and the optical fibers at the output end are used as the N optical fibers 221 at the optical output end.
  • the light incident section 100 may include the above-mentioned light incident end fibers 110
  • the light exit section 200 may include the above-mentioned N light exit end fibers 221 .
  • an optical filter structure 210 is a segment of grating, and a segment of grating filters an optical signal of one wavelength with a specific transmittance.
  • the above grating is a diffraction grating formed by periodically modulating the refractive index of the light exit segment 200 in the axial direction by a certain method.
  • the above-mentioned grating may be a fiber grating (ie, the grating is formed on an optical fiber), or may be a waveguide grating (ie, the grating is formed on a waveguide).
  • the fiber grating may be a fiber Bragg grating (FBG) or a long period fiber grating (LPFG).
  • the incident light coherent field pattern is written into the fiber core by means of ultraviolet light exposure, and the periodic change of the refractive index along the axis of the fiber core is generated in the fiber core, thereby Form a permanent space phase grating.
  • fiber gratings can also be fabricated by femtosecond lasers, carbon dioxide lasers, and the like.
  • the above-mentioned preparation method of the fiber grating can also be used.
  • a section of grating can be viewed as a band-stop filter for a specific center wavelength.
  • the optical signal of a specific center wavelength is completely reflected, and the optical signals of other wavelengths will continue to transmit through the grating; or, the grating filters the optical signal of a specific center wavelength with a certain transmittance, That is, the optical signal of a specific center wavelength is partially reflected, and the optical signal part of the specific center wavelength continues to transmit through the grating, and the optical signal of the remaining wavelengths will continue to transmit through the grating.
  • the grating filters is an optical signal in a wavelength range, and the optical signal in this wavelength range has the above-mentioned center wavelength.
  • the above-mentioned central wavelength and transmittance can be controlled by adjusting the grating period, the grating pitch and the exposure time in the process of making the grating.
  • the above-mentioned light filter structure 210 may also be a filter film.
  • the filter film can be a thin film coated on a waveguide or optical fiber.
  • the end face of the waveguide can be coated, or the waveguide can be coated after opening, or the end face of the optical fiber can be coated, or the optical fiber can be coated after opening.
  • the number and position of the filter films on each light emitting segment 200 can be set with reference to the corresponding description of the grating, which will not be repeated here. It can be understood that the filter film filters optical signals in a wavelength range, and the optical signals in this wavelength range have the above-mentioned central wavelength.
  • each light exit segment 200 can be implemented in various ways:
  • each light emitting section 200 is provided with at most one optical filter structure 210, and the fewer the number of optical filter structures 210, the simpler the production process of the optical splitter, and the less difficult it is to manufacture, which is conducive to reducing costs.
  • Case 1 each of the N light-emitting sections 200 is provided with an optical filter structure 210, and each light-emitting section 200 filters an optical signal of one wavelength, that is, the light on each light-emitting section 200 The filtering structure 210 filters an optical signal of one wavelength.
  • there is one light emitting segment 200 without the light filtering structure 210 there is one light emitting segment 200 without the light filtering structure 210 , and each of the remaining N ⁇ 1 light emitting segments 200 is provided with one light filtering structure 210 .
  • At least one light exit segment 200 is provided with M optical filter structures 210 , each light exit segment 200 filters optical signals of M wavelengths, and M is an integer greater than or equal to 2.
  • N 8
  • each light exit section 200 is provided with two light filter structures 210 , or some light exit sections 200 are provided with one light filter structure 210 , and the rest of the light exit sections 200 are provided with two light filter structures 210 .
  • the N light emitting segments 200 there is one light emitting segment 200 that is not provided with the light filtering structure 210 . At least one optical filter structure 210 is provided in each of the remaining light exit segments 200 .
  • Each light exit section 200 is provided with one optical filter structure 210 or two optical filter structures 210 are provided.
  • the optical filter structure 210 is arranged on the intermediate branch waveguide 232, the light exit waveguide end 231 (as shown in FIG. 1(2)), and the light exit fiber 221 (as shown in FIG. 1(1), At least one of Figures 1(3) and 1(4)).
  • the optical fiber 221 at the light output end includes the optical fiber 222 on the optical fiber array 220, the ribbon fiber 223, the pigtail fiber 224, and the like.
  • the optical splitter further includes a splitter 225, one end of the splitter 225 is connected to the ribbon fiber 223, the other end is connected to the pigtail 224, and the ribbon fiber 223 is located between the splitter 225 and the fiber 222 on the fiber array 220.
  • the optical filter structure 210 is arranged on the optical fiber 221 at the light output end, and includes: the optical fiber 222 (as shown in FIG. 1(1)), the ribbon fiber 223 (as shown in FIG. 1(3)) and the fiber optic in the pigtail with the optical filter structure 210 arranged on the fiber array 220. at least one.
  • the M optical filter structures 210 on one light exit section 200 are all disposed on the light exit waveguide end 231; or may all be disposed on the light exit end fiber 221.
  • the M optical filter structures 210 on one light exit section 200 are all disposed on the optical fibers 222 on the optical fiber array 220; or as shown in FIG. 1(3)), the M optical filter structures 210 on one light exit section 200
  • the M optical filter structures 210 are all arranged on the ribbon fiber 223; or as shown in FIG.
  • the M optical filter structures 210 on one light exit section 200 may also be dispersedly arranged on the light exit waveguide end 231, the light exit end fiber 221 (including the fiber 222, the ribbon fiber 223 and the pigtail fiber 224 on the fiber array 220) and the intermediate branch waveguide 232 on at least two of them.
  • the optical filtering structure 210 is disposed on the optical fiber 221 at the light exit end.
  • the fixing box 260 can straighten and fix the part with the grating on the tape fiber 223 as much as possible, and set it in the air, so that the grating can reduce the influence of external environmental factors as much as possible, such as the stress generated by artificial pulling, wind blowing, etc., on the grating
  • the effect of the period plays a role in protecting the grating.
  • FIG. 2 is a schematic diagram of the fixing of the fixing box 260 and the tape fiber 223.
  • the middle part of the tape fiber 223 is stripped of the tape fiber 223 sleeve, and the fiber is exposed. Gratings are engraved on the bare fiber.
  • the ribbon fibers 223 are respectively fixed at the ends, so that the bare optical fibers in the middle of the ribbon fibers 223 are straightened and fixed.
  • the fixing box body 260 can be fixed with a fixing glue to fix the tape fiber 223, or can also be fixed by means of clipping or the like.
  • optical filter structure 210 is a filter film
  • the methods shown in FIG. 1(1) to FIG. 1(4) can also be used, and the above beneficial effects can also be achieved, which will not be repeated here.
  • the above-mentioned optical input end fiber 110 refers to the fiber at the end of the optical splitter with fewer branches.
  • the above-mentioned light-emitting end fiber 221 refers to the fiber at each end of the optical splitter with many branches.
  • the optical signal can enter from the optical fiber 110 at the light input end, is divided into multiple optical signals by the optical splitter, and output through each of the optical fibers 221 at the light output end.
  • the optical signal may also enter from the light-emitting end fiber 221 and output through the light-incoming end fiber 110 .
  • the splitter is an equal splitter.
  • the powers of the optical signals output by the N light output sections 200 of the equal splitter are the same or substantially the same.
  • the equal splitter may be a PLC splitter.
  • the equal splitter can also be an FBT splitter.
  • the optical splitter is an unequal splitter.
  • the N light emitting sections 200 of the unequal ratio splitter include one unequal ratio light emitting section 201 and N-1 equal ratio light emitting sections 202 .
  • the powers of the optical signals output by each of the proportional optical sections 202 are the same or substantially the same.
  • the unequal ratio optical output section 201 is also generally referred to as the large branch ratio optical section 200.
  • the power of the optical signal output by the unequal ratio optical output section 201 is different or greatly different from the power of the optical signal output by each of the equal ratio optical output sections 202.
  • the power of the optical signal output by the unequal ratio optical output segments 201 is greater than the power of the optical signals output by each of the equal ratio optical output segments 202 .
  • the unequal optical splitter includes one unequal ratio output optical fiber 221 and N-1 equal ratio optical output fibers 221 .
  • the unequal splitter can be a PLC splitter or an FBT splitter.
  • the unequal splitter can also be a splitter that combines PLC and FBT.
  • the 1:2 optical splitting section in FIG. 5 can be implemented by FBT, and the 1:8 optical splitting section can be implemented by PLC.
  • the output optical power ratio of the two branch ends of the 1:2 beam splitting section is 30%:70%, and 30% of the branch ends of the 1:2 beam splitting section are connected to the 1:8 beam splitting section.
  • an optical filter structure 210 is provided in the unequal ratio light output section 201, and the unequal ratio light output section 201 filters an optical signal of one wavelength. There is at most one proportional light emitting segment 202 without the optical filter structure 210 in each of the proportional light emitting segments 202 .
  • the unequal ratio light emitting segment 201 and any of the equal ratio light emitting segments 202 satisfies that there is no light filtering structure 210 capable of filtering the same wavelength. For example, if the unequal ratio optical section 201 filters the optical signal of wavelength 1, and the first proportional optical section 202 filters the optical signal of wavelength 1 and wavelength 2, it is considered that there is an optical filter structure 210 capable of filtering the same wavelength. If the unequal ratio optical section 201 filters the optical signal of wavelength 1, and the first proportional optical section 202 filters the optical signal of wavelength 2 and wavelength 3, it is considered that there is no optical filter structure 210 between the two that can filter the same wavelength.
  • the unequal ratio light output segment 201 is not provided with the light filter structure 210 , and each of the proportional light output segments 202 is provided with at least one light filter structure 210 .
  • At least two optical filter structures 210 are provided in the unequal ratio light exit section 201 .
  • the difference between the unequal-ratio light-emitting segment 201 and any of the equal-ratio light-emitting segments 202 satisfies that there is no optical filtering structure 210 capable of filtering the same wavelength.
  • the unequal ratio optical section 201 filters the optical signals of wavelength 1 and wavelength 3
  • the one-proportional optical section 202 filters the optical signals of wavelength 1 and wavelength 2 it is considered that there is a device capable of filtering the same wavelength.
  • the light filtering structure 210 If the unequal ratio optical section 201 filters the optical signals of wavelength 1 and wavelength 3, and the first proportional optical section 202 filters the optical signals of wavelength 2 and wavelength 4, it is considered that there is no optical filter structure 210 capable of filtering the same wavelength.
  • the two light emitting sections 200 satisfy the above condition 1.
  • one light emitting section 200 is not provided with the light filtering structure 210 (that is, the number of filtered wavelengths is 0), and the other light emitting section 200 is provided with at least one optical filtering structure 210 (that is, the number of filtered wavelengths is at least 1), Then it can be considered that the above condition 1 is satisfied.
  • one light-emitting section 200 is provided with one optical filter structure 210 (that is, the number of filtered wavelengths is one), and the other light-emitting section 200 is provided with two optical filter structures 210 (for example, the number of filtered wavelengths is two). ), it can be considered that the above condition 1 is satisfied.
  • the two light emitting sections 200 satisfy the above condition 1.
  • the wavelengths filtered by one light emitting section 200 are wavelength 1 and wavelength 2
  • the wavelengths filtered by another light emitting section 200 are wavelength 1 and wavelength 3
  • the above condition 1 is satisfied.
  • the wavelengths filtered by one light emitting section 200 are wavelength 1 and wavelength 2
  • the wavelengths filtered by another light emitting section 200 are wavelength 3 and wavelength 4, it is considered that the above condition 1 is satisfied.
  • the two light emitting sections 200 can filter the optical signal with wavelength 1, the transmittance of one light emitting section 200 to the optical signal of wavelength 1 is R1, and the other light emitting section 200 is to the light of wavelength 1. If the transmittance of the signal is R2, and R1 and R2 are different, it is considered that the two light-emitting sections 200 satisfy the above-mentioned condition 2.
  • the unequal ratio optical splitter may also include two or more unequal ratio light output segments 201 .
  • the embodiments of the present application further provide an ODN, where the ODN includes a primary optical splitter and a secondary optical splitter.
  • the primary optical splitter and the secondary optical splitter are the optical splitters described in the above embodiments.
  • the ODN can also include ODF, SSC, FDT, FAT, ATB, etc.
  • the primary optical splitter can be set in FDT, FAT, ODF, SSC and other devices, and the secondary optical splitter can be set in FDT, FAT, ODF, SSC, etc. etc. in the device.
  • the primary beam splitter and the secondary beam splitter can be installed in different types of devices, or can be in the same device.
  • the primary optical splitter and the secondary optical splitter in each embodiment of the present application are relative concepts, and the light incident section 100 of the secondary optical splitter is directly or indirectly connected to the light output section 200 of the primary optical splitter.
  • the ODN shown in FIG. 7 includes four levels of optical splitters, namely optical splitter 11 , optical splitter 21 , optical splitter 31 and optical splitter 41 .
  • the light incident section 100 of the optical splitter 12 is directly connected to a light outgoing section 200 of the optical splitter 11 through an optical fiber, and the optical splitter 11 may be referred to as a primary optical splitter, and the optical splitter 12 may be referred to as a secondary optical splitter.
  • the light incident section 100 of the optical splitter 31 is directly connected to the first light output section 200 of the optical splitter 21 through an optical fiber, and the optical splitter 21 can also be called a primary optical splitter, and the optical splitter 31 can be called a secondary optical splitter.
  • the light-incident section 100 of the optical splitter 31 is indirectly connected to the first light-emitting section 200 of the optical splitter 11 through the optical splitter 21, then the optical splitter 11 can be called a primary optical splitter, and the optical splitter 31 can be called a secondary optical splitter device.
  • the light incident section 100 of the first-level optical splitter is referred to as the first light-incident section 100
  • the light-exit section 200 of the first-level optical splitter is referred to as the first light-exit section 200
  • the light-incident section 100 of the second-level optical splitter is referred to as The second light incident section 100 and the light exit section 200 of the secondary beam splitter are called the second light exit section 200 .
  • a first light exit segment 200 is connected to the second light entrance segment 100, and it can be understood that it can be directly connected or indirectly connected.
  • the first light incident section 100, a pair of mutually connected first light exit sections 200 and second light incident sections 100, and a second light exit section 200 form an optical link.
  • the ODN includes one first-level optical splitter 11 and eight second-level optical splitters 21 , the eight second-level optical splitters are the same, and only two second-level optical splitters are shown in FIG. 6 . , and the remaining secondary beam splitters are omitted and not shown.
  • the wavelengths filtered by any two first light emitting sections 200 are different, and the wavelengths filtered by any first light emitting section 200 and any second light emitting section 200 are different. Therefore, the optical link in the ODN shown in Figure 6 can filter optical signals of 16 wavelengths. Therefore, in the process that the OLT sends the test optical signal to identify the optical link where each ONU is located, the OLT needs to send the test optical signal of 16 wavelengths. Not only a lot of wavelength resources are occupied, but also the scanning wavelength range on the OLT side is too large and the cost is high.
  • any two optical links satisfy at least one of the following conditions 1 and 2: condition 1: at least one of the filtered wavelengths is different; condition 2: for at least one The transmittance of optical signals of different wavelengths is different.
  • the two optical links are considered to satisfy the above condition 1. For example, if the number of wavelength types filtered by one optical link is 0, and the number of wavelength types filtered by another optical link is at least one, it can be considered that the above condition 1 is satisfied. For another example, if the number of wavelength types filtered by one optical link is one, and the number of wavelength types filtered by another optical link is two, it can be considered that the above condition 1 is satisfied.
  • the two optical links can filter the same number of types of optical signals, and the wavelengths filtered by the two optical links are not all the same, it is considered that the two optical links meet the above condition 1.
  • the wavelengths filtered by one optical link are wavelength 1 and wavelength 2
  • the wavelengths filtered by another optical link are wavelength 1 and wavelength 3
  • the above condition 1 is satisfied.
  • the wavelengths filtered by one optical link are wavelength 1 and wavelength 2
  • the wavelengths filtered by another optical link are wavelength 3 and wavelength 4, it is considered that the above condition 1 is satisfied.
  • any two optical splitting sections of the optical splitter satisfy at least one of the above-mentioned conditions 1 and 2, and any two optical links satisfy at least one of the above-mentioned conditions 1 and 2, and the light-emitting section is provided with an optical filter structure.
  • the difficulty and cost of manufacturing devices are easy to implement.
  • both the primary beam splitter and the secondary beam splitter are equal splitters, and there are multiple secondary beam splitters (only two secondary beam splitters are shown in FIGS. 8 to 10 . and the others are not shown), each secondary optical splitter is the same optical splitter, and any primary optical splitter and any secondary optical splitter are different optical splitters. Therefore, even if each secondary optical splitter is the same optical splitter, since any two first light-emitting sections 200 of the primary optical splitter satisfy at least one of the above conditions 1 and 2, the optical link where the ONU is located can still be identified.
  • the first light emitting section 200 of the second optical splitter identifies the port of the primary optical splitter on the optical link where the ONU is located; at the same time, since any two second optical emitting sections 200 of the secondary optical splitter satisfy at least the above condition 1 and condition 2, it can be
  • the second optical outgoing section 200 of the optical link where the ONU is located is further identified, that is, the port of the secondary optical splitter on the optical link where the ONU is located is identified.
  • the secondary optical splitter is the same optical splitter, which can greatly reduce the types of optical splitters in the ODN. One is to reduce the production cost of the manufacturer, and the other is to facilitate the installation of the construction personnel, and it is not easy to make mistakes during the installation process.
  • any first light emitting section 200 and any second light emitting section 200 satisfy that there is no light filtering structure 210 capable of filtering the same wavelength. Therefore, for any optical link, there is only one optical filter structure 210 for filtering the optical signal of the same wavelength with a specific transmittance, and the optical splitters of different levels will not superimpose the filtering of the optical signal of the same wavelength.
  • the optical splitters do not affect each other when filtering optical signals, and multiple levels of optical splitters can be set in the ODN, such as four or more levels of optical splitters, which can identify the optical link where the ONU is located.
  • the wavelengths filtered by any two first light emitting sections 200 are the same, and the transmittances of any two first light emitting sections 200 to the filtered wavelengths are different.
  • the wavelengths filtered by any two second light emitting sections 200 are the same, and the transmittances of any two second light emitting sections 200 to the filtered wavelengths are different. That is, each port of the primary optical splitter is distinguished by transmittance, and each port of the secondary optical splitter is distinguished by transmittance, and the optical splitter level is distinguished by the filtered wavelength.
  • the types of test light can be further reduced and wavelength resources can be saved.
  • FIG. 9 the wavelengths filtered by any two first light emitting sections 200 are the same, and the transmittances of any two first light emitting sections 200 to the filtered wavelengths are different.
  • the wavelengths filtered by any two second light emitting sections 200 are the same, and the transmittances of any two second light emitting sections 200 to the filtered wavelengths are different. That is, each port of the primary optical splitter
  • the optical splitter level can also be distinguished by wavelength, and the optical splitter port can be distinguished by the combination of wavelength and transmittance, which can not only reduce the types of test light, but also enable different ports
  • the transmittance interval for the same wavelength is as large as possible, which is more conducive to identifying the optical link and improving the accuracy of identifying the optical link.
  • the splitter level can also be distinguished by transmittance, and the splitter port can be distinguished by wavelength.
  • At least M optical filters can be set on at least one light exit section 200 of the primary optical splitter
  • at least M light filtering structures 210 may also be arranged on at least one light exit section 200 of the secondary optical splitter, where M is an integer greater than or equal to 2.
  • two optical filter structures 210 are set on each light exit section 200 of the primary beam splitter and the secondary beam splitter as an example, as shown in FIG.
  • the transmittance of the light exit section 2001 of the primary beam splitter to wavelength 1 is 0%, and the transmittance to wavelength 2 is 0%; the transmittance of light-emitting section 2006 to wavelength 1 is 40%, and the transmittance to wavelength 2 is 80%, and the remaining light-emitting section 200 and the secondary beam splitter Similarly, the transmittance of wavelengths can be referred to FIG. 11 , which will not be repeated here.
  • the number of optical filter structures 210 provided on each light exit section 200 of the primary optical splitter may be different.
  • there is a light exit section 200 without the light filter structure 210 and there is also a light exit section 200 with one light filter structure 210.
  • Each light emitting section 200 is distinguished by the number of light filtering structures, the filtered wavelengths, and the corresponding transmittances.
  • Various combinations further reduce the types of test light and expand the transmittance interval.
  • the second-level optical splitter is the same as the above-mentioned first-level optical splitter, and details are not repeated here.
  • both the primary beam splitter and the secondary beam splitter are unequal beam splitters.
  • the number of optical splitters in each stage is one, and the light incident section 100 of the next stage optical splitter is connected to the unequal ratio light output section 201 of the previous optical splitter. It can be understood that, in other examples, there may also be at least two optical splitters at the same level.
  • the optical filter structure 210 is not provided on the unequal ratio light output section 201 of the optical splitters at all levels. As shown in FIG. 7 , it includes 3 unequal splitters (spectroscopes 11, 21, 31 in FIG. 7 ) and one equal splitter (spectroscope 41 in FIG. 7 ).
  • the splitter distinguishes the splitter level by wavelength and the splitter port by transmittance. It can be understood that, in other embodiments, as shown in FIG. 15 , the unequal splitters at all levels can also distinguish the splitter levels by transmittance, and distinguish splitter ports by wavelength. Or in other embodiments, as shown in FIG. 16 , the unequal splitters at all levels can also distinguish the splitter levels by wavelength, and distinguish splitter ports by the combination of wavelength and transmittance.
  • an optical filter structure 210 is disposed on the unequal ratio light output section 201 .
  • the unequal ratio light output sections 201 of the unequal splitters at all levels can filter optical signals of the same wavelength, and can also filter optical signals of different wavelengths.
  • the unequal splitters at all levels can distinguish the splitter levels by wavelength or transmittance or their combination, and can also distinguish splitter ports by wavelength or transmittance or their combination. It can also be shown in Figures 17 and 18 that the unequal splitters at each level are the same unequal splitters. As shown in FIG.
  • each proportional light-emitting section 202 of the first-level optical splitter 11 only filters wavelength 1
  • each equivalent-proportional light-emitting section 202 of the second-level optical splitter 21 filters wavelength 2 with a transmittance of 70%, and also simultaneously
  • the fourth-level optical splitter is an equal ratio
  • Each equal-ratio optical output section 202 of the unequal splitter of each level and the equal-ratio splitter of the fourth level both filter the optical signal of wavelength 1, and distinguish ports by the transmittance of wavelength 1.
  • the levels of the individual beamsplitters are differentiated by wavelength 2 transmittance. Therefore, only two types of optical splitters are included in the ODN, one is to reduce the production cost of the manufacturer, and the other is to facilitate the installation of the construction personnel, and it is not easy to make mistakes in the installation process.
  • each equal-ratio optical output section 202 of each level of unequal splitter and the fourth-level equal splitter both filter the optical signals of wavelength 1 and wavelength 2, and pass the transmittance of wavelength 1 and wavelength 2 of the optical signal.
  • the transmittance is used to distinguish the ports, and the level of each optical splitter is distinguished by the transmittance of wavelength 3.
  • the ODN also includes only two types of optical splitters. The fewer types of optical splitters in the ODN, the more favorable it is to reduce costs, and it is not easy to make mistakes in the installation process.
  • the unequal ratio light emitting segment 201 and any of the equal ratio light emitting segments 202 satisfies that there is no light filtering structure 210 capable of filtering the same wavelength.
  • the wavelength filtered by the unequal ratio light emitting section 201 will not affect each other with the wavelength filtered by the equal ratio light emitting section 202, and then the ODN More levels of optical splitters can be set in the switch, all of which can identify the optical link where the ONU is located.
  • proportional light output section 202 of the unequal optical splitters at all levels can refer to the above-mentioned introductions about the equal optical splitters at all levels (for example, FIG. 8 to FIG. 14 ), which also has the effects described above. It is not repeated here.
  • At least two light filter structures 210 may also be provided on the unequal ratio light output section 201 .
  • the first-level optical splitter 31 is an unequal splitter
  • the second-level optical splitter 41 is an equal splitter.
  • the first-level optical splitter and the second-level optical splitter may also have an optical filter structure 210 that can filter the same wavelength, as long as each optical link satisfies at least one of the above-mentioned conditions 1 and 2. One is enough.
  • the PON system in this application can be next-generation PON (NG-PON), NG-PON1, NG-PON2, gigabit-capable PON (GPON), 10 gigabit per second PON ( 10gigabit per second PON, XG-PON), symmetric 10 gigabit passive optical network (10-gigabit-capable symmetric passive optical network, XGS-PON), Ethernet PON (Ethernet PON, EPON), 10 gigabits per second EPON (10gigabit per second EPON, 10G-EPON), next-generation EPON (NG-EPON), wavelength-division multiplexing (WDM) PON, time-and wavelength-division multiplexing (time-and wavelength) -division multiplexing, TWDM) PON, point-to-point (point-to-point, P2P) WDM PON (P2P-WDM PON), asynchronous transfer mode PON (asynchronous transfer mode PON, APON), broadband PON (broadband PON
  • 25 gigabit per second PON 25gigabit per second PON, 25G-PON
  • 50 gigabit per second PON 50gigabit per second PON, 50G-PON
  • 100 gigabit per second PON 100gigabit per second PON (100gigabit per second PON, 100G -PON)
  • 25 gigabits per second EPON 25gigabit per second EPON, 25G-EPON
  • 50 gigabits per second EPON 50gigabit per second EPON, 50G-EPON
  • 100 gigabits per second EPON 100 gigabits per second EPON (100gigabit per second EPON, 100G-EPON
  • other various PON systems specified by ITU or other various PON systems specified by IEEE, etc.
  • the PON system may include an OLT, an ODN, and at least one ONU (as shown in Figures 7-18).
  • the direction from the OLT to the ONU is defined as the downstream direction
  • the direction from the ONU to the OLT is defined as the upstream direction.
  • the OLT is the core component of the optical access network, usually located in the central office (Central Office, CO), and can manage at least one ONU in a unified manner.
  • the OLT is used to provide data and management for each ONU connected.
  • the OLT can be used to send optical signals to each ONU, receive information fed back by each ONU, and process the information or other data fed back by the ONU.
  • the ONU is used to receive the data sent by the OLT, respond to the management commands of the OLT, buffer the user's Ethernet data, and send data to the upstream direction in the sending window allocated by the OLT, and so on.
  • the ODN may be the ODN described in the foregoing embodiment, and details are not described herein again. It can be understood that the following embodiments also have the beneficial effects described in the above ODN embodiments.
  • the ODN includes a first-level optical splitter 11.
  • the first-level optical splitter includes 8 ports, and each port is respectively connected to a second-level optical splitter, that is, there are a total of eight second-level optical splitters.
  • Figure 14 shows only two secondary optical splitters 21 and 22, wherein the secondary optical splitter 21 is connected to port 1 of the primary optical splitter, the secondary optical splitter 22 is connected to port 6 of the primary optical splitter, and the remaining secondary optical splitters The optical splitter is not shown, and the remaining secondary optical splitters and the secondary optical splitters 21 and 22 may be the same optical splitters.
  • Each secondary optical splitter includes 8 ports, each port can be connected to an ONU, wherein, port 4 of the secondary optical splitter 21 is connected to the first ONU 301, port 7 of the secondary optical splitter 22 is connected to the second ONU 302, and the rest ONU is not shown.
  • the ODN includes a total of 64 optical links.
  • the optical link between the OLT and the first ONU 301 is referred to as the first optical link
  • the optical link between the OLT and the second ONU 302 is referred to as the second optical link.
  • FIG. 14 is only an example diagram, and the optical link where the first ONU 301 and the second ONU 302 are located is not limited to the optical link shown in FIG. 14 .
  • the following embodiments relate to the first ONU 301 and the second ONU 301
  • the relevant description of the ONU 302 may be applicable to the ONU on any optical link in the ODN, and may also be applicable to the ONU in other ODN embodiments.
  • the embodiment of the present application also provides a method for identifying the optical link where the ONU is located in the PON system. As shown in Figure 19, the method includes:
  • Step S10 the OLT sends down test light of Q wavelengths, wherein Q is an integer greater than or equal to 1, and the first optical link between the OLT and the first ONU 301 has a specific transmittance for the test light of at least one wavelength .
  • Q is an integer greater than or equal to 1
  • the first optical link between the OLT and the first ONU 301 has a specific transmittance for the test light of at least one wavelength .
  • Q is at least equal to the number of wavelength species of the optical signal filtered by the first optical link.
  • the optical filter structure 210 is not provided in the light exit section 200 of the primary optical splitter where the first optical link is located, and the light exit section 200 of the secondary optical splitter where the first optical link is located can filter wavelengths 3 and 4 Therefore, the number of wavelengths of the optical signal that can be filtered by the first optical link is 2, that is, Q is at least equal to 2, and the OLT sends at least the test light of wavelength 3 and wavelength 4 downstream.
  • Q is equal to the number of wavelength species of optical signals filtered by all optical links in the ODN.
  • the ODN can filter the optical signals of wavelength 1, wavelength 2, wavelength 3 and wavelength 4, so the OLT can send down the test light of wavelength 1, wavelength 2, wavelength 3 and wavelength 4. That is, Q is equal to 4.
  • Q is equal to 4.
  • the first optical link is provided with at least one optical filter structure, and one optical filter structure filters the test light of one wavelength with a specific transmittance.
  • the wavelength 3 is filtered with a transmittance of 0%
  • the wavelength 4 is filtered with a transmittance of 0%.
  • the first optical link has a specific transmittance to the test light, which can be understood as the first optical link has a specific transmittance to each test light.
  • the transmittance of test light of one wavelength is all 100%. Generally, there is at most one such optical link in each ODN.
  • step S10 includes: the OLT sequentially sends down the test light of Q wavelengths in sequence.
  • Step S20 the first ONU 301 receives the test light of Q wavelengths sent by the OLT.
  • Q is greater than or equal to 2
  • step S20 includes: the ONU sequentially receives the test light of Q wavelengths sent by the OLT according to the time sequence.
  • Step S30 the first ONU 301 determines the received power value of the received test light of each wavelength.
  • Step S40 the first ONU 301 generates feedback information, where the feedback information is used to indicate the received power value of the test light.
  • Step S50 the first ONU 301 sends feedback information to the OLT.
  • one piece of feedback information indicates the received power value of the test light of one wavelength.
  • the feedback information may be one piece, and one piece of feedback information indicates the received power value of the test light of Q wavelengths.
  • Step S60 the OLT receives the feedback information fed back by the first ONU 301 .
  • Step S70 the OLT determines the transmittance according to the received power value of the test light of at least one wavelength. Including the following ways:
  • the received power value of the test light received by the OLT includes not only the received power value of the test light with a specific transmittance on the first optical link, but also the test with full transmittance on the first optical link the received power value of the light, the method further includes: the OLT determines the maximum value of the received multiple received power values as the reference received power value P0, and step S70 includes: the OLT tests the received power value of the light according to at least one wavelength With reference to the received power value, the transmittance of the test light of at least one wavelength in the first optical link is determined.
  • the OLT may take the received power value P1 smaller than P0 as the received power value of the test light with a specific transmittance on the first optical link.
  • the transmittance may eg be equal to 10 ⁇ (P1/10)/10 ⁇ (P0/10).
  • the transmittance of wavelength 3 is 50%
  • the transmittance of wavelength 4 is 50%.
  • the method further includes: the OLT sends a service optical signal downstream; the ONU receives the service optical signal, the ONU determines a service optical receive power value of the service optical signal, and the ONU sends service optical information to the OLT, and the service optical information is used to indicate the service optical signal.
  • Service optical receive power value of the optical signal is used to indicate the service optical signal.
  • the OLT receives the service light information fed back by the first ONU 301; the OLT determines the transmittance of the test light of at least one wavelength on the first optical link according to the received power value of the test light of at least one wavelength and the received power value of the service light.
  • the service optical received power value in this mode has full transmittance on the first optical link, which is similar to P0 in the first mode, and the calculation formula of the transmittance is the same as that in the first mode, and will not be repeated here.
  • an optical link may be represented by an optical link number. For example, if 64 optical links are included in FIG. 14 , there are a total of 64 optical link numbers.
  • the optical link can also be characterized by the level of the optical splitter and the port number of the optical splitter. For example, for the first optical link where the first ONU 301 shown in FIG. 14 is located, it can be characterized as: a first-level optical splitter Port 1 and secondary splitter port 4.
  • the relationship between the first optical link and the wavelength and transmittance may be: port 1 of the primary optical splitter and port 4 of the secondary optical splitter, the transmittance of wavelength 3 is 0%, and the transmittance of wavelength 4 is 0%.
  • the OLT When performing the above step S80, the OLT also needs to know which wavelength of the received power value of the test light the received power value is.
  • the method further includes that the OLT determines the wavelength of the test light corresponding to the received power value. Including the following ways:
  • Mode 1 After the OLT sends a test light of one wavelength in the downlink each time, it waits to receive the feedback information fed back by the first ONU301;
  • the ONU After each time the ONU receives the test light of one wavelength, it determines the received power value of the test light and generates feedback information, and sends the feedback information to the OLT, where the feedback information indicates the received power value of the test light.
  • the OLT After receiving the feedback information, the OLT sends down the test light of the next wavelength.
  • the ONU receives the test light of the next wavelength, and the ONU repeats the above steps of generating and sending feedback information. Therefore, the wavelength of the test light sent before the time when the OLT receives the feedback information is the wavelength of the test light corresponding to the received power value indicated by the feedback information.
  • no additional information is required to indicate the wavelength, and the wavelength can be determined directly according to the time sequence. No additional changes to the message format are required.
  • Method 2 After the OLT sends down the test light of Q wavelengths in sequence, the ONU receives the test light of Q wavelengths in sequence, and determines the received power values of the Q wavelengths respectively, and the ONU records the reception of the test light of the Q wavelengths. timing.
  • the ONU may send Q pieces of feedback information to the OLT, and each piece of feedback information indicates the received power value of one wavelength.
  • the ONU sequentially sends the corresponding Q pieces of feedback information according to the receiving sequence of the test light of various wavelengths.
  • the OLT can determine the wavelength of the corresponding test light according to the timing of the received feedback information.
  • the ONU may send a piece of feedback information to the OLT, where the feedback information indicates the received power values of the Q wavelengths and the reception timing of the test light of the Q wavelengths.
  • Each of the Q wavelengths of test light sent downstream by the OLT carries a label, wherein any two wavelengths of test light carry different labels; the feedback information is used to indicate the reception of the test light The power value and the label carried in the test light corresponding to the received power value; the method further includes: the OLT determines the wavelength of the test light corresponding to the received power value according to the label.
  • the OLT sending test light and the ONU sending feedback information are not limited by time sequence, and the implementation is more flexible.
  • the method may further include: the OLT sends optical link information, where the optical link information is used to indicate the first optical link.
  • the OLT can send optical link information to other servers.
  • the optical link information is specifically used to indicate all levels of optical splitters and ports of the optical splitters on the first optical link.
  • the optical link information includes identification information of each optical splitter in each level of optical splitters, and identification information of each port located on the first optical link.
  • the ONU feeds back the received power value to the OLT, and the OLT determines the transmittance according to the received power value, and further determines the optical link information.
  • the transmittance can also be determined by the ONU according to the received power value, and the transmittance can be fed back to the OLT (for example, the feedback information is used to indicate the transmittance), and the optical link information can be determined by the OLT,
  • the feedback information is used to indicate the transmittance
  • the transmittance can also be determined by the ONU according to the received power value, and the optical link information can be further determined, and then the ONU feeds back the optical link information to the OLT (for example, the feedback information is used to indicate the optical link information).
  • the OLT for example, the feedback information is used to indicate the optical link information.
  • the present invention also provides an OLT 400 as described in each of the above embodiments.
  • the OLT 400 includes a processor 410 and a transceiver 420 .
  • the transceiver 420 includes an optical transmitter and an optical receiver.
  • the optical transmitter converts the electrical signal into an optical signal and sends the optical signal to the ODN
  • the optical receiver receives the optical signal from the ODN network and converts the optical signal into an electrical signal.
  • the light transmitter can be realized by a light-emitting device, such as a gas laser, a solid-state laser, a liquid laser, a semiconductor laser, a directly modulated laser, and the like.
  • the optical receiver may be implemented by a photodetector, such as a photodetector or a photodiode (eg, an avalanche diode) or the like.
  • the transceiver 420 can be an optical module.
  • the optical module may also include a control circuit.
  • the above-mentioned optical transmitter has a wavelength adjustable function, and can be a Distributed Bragg Reflector (DBR) laser, a group of Distributed Feedback Bragg (DFB) lasers, or other forms.
  • the optical module may include an optical transmitter that transmits the service wavelength and the test wavelength simultaneously.
  • the optical module may also include two optical transmitters, one optical transmitter is used to transmit service light, and the other optical transmitter is used to transmit test light.
  • the processor 410 is used to implement functions such as ONU management, DBA (Dynamic Bandwidth Allocation, dynamic bandwidth allocation), ONU registration, and data sending and receiving.
  • the processor 410 can be implemented by a hardware circuit, by a software program, or by a combination of hardware and software, such as a Field-Programmable Gate Array (FPGA), or a dedicated integrated chip (Application Specific Integrated Circuit (ASIC) or System on Chip (SoC), or Media Access Control (MAC), or Central Processor Unit (CPU), or Network Processor (NP) ), or a digital signal processing circuit (Digital Signal Processor, DSP), or a microcontroller (Micro Controller Unit, MCU), or a programmable controller (Programmable Logic Device, PLD) or other integrated chips.
  • the processor 410 may perform the above-mentioned determination of transmittance, determination of reference received power value P0, determination of optical link, and the like.
  • the OLT 400 further includes a memory 430, which can be a read-only memory (Read Only Memory, ROM), a static storage device, a dynamic storage device, or a random access memory (Random Access Memory, RAM), or a register, or a non-volatile memory non-volatile memory, such as flash, or at least one disk storage.
  • a memory 430 can be a read-only memory (Read Only Memory, ROM), a static storage device, a dynamic storage device, or a random access memory (Random Access Memory, RAM), or a register, or a non-volatile memory non-volatile memory, such as flash, or at least one disk storage.
  • program codes for implementing the technical solutions provided by the embodiments of the present invention are stored in the memory 430 and executed by the processor 410 .
  • the memory 430 and the processor 410 may be located on different physical entities, or may be partially or fully integrated into one physical entity, and the physical entity may be a Field-Programmable Gate Array (FPGA), or Application Specific Integrated Circuit (ASIC) or System on Chip (SoC), or Central Processor Unit (CPU), or Network Processor (NP), or digital signal processing circuit (Digital Signal Processor, DSP), or microcontroller (Micro Controller Unit, MCU), or programmable controller (Programmable Logic Device, PLD) or other integrated chips.
  • FPGA Field-Programmable Gate Array
  • ASIC Application Specific Integrated Circuit
  • SoC System on Chip
  • CPU Central Processor Unit
  • NP Network Processor
  • DSP Digital Signal Processor
  • MCU Micro Controller Unit
  • PLD programmable controller
  • OLT 400 also includes wavelength division multiplexing (WDM) device 440 .
  • a wavelength division multiplexer is connected to the transceiver 420, and when the OLT 400 transmits an optical signal, the wavelength division multiplexer acts as a multiplexer. When the OLT400 receives the optical signal, the wavelength division multiplexer acts as a demultiplexer.
  • a wavelength division multiplexer can also be called an optocoupler.
  • wavelength division multiplexer 440 may also exist independently of the OLT 400 .
  • the OLT 400 shown in FIG. 20 executes steps S10 , S60 , S70 , and S80 in the embodiment shown in FIG. 19 .
  • the processor 410 executes steps S70 and S80.
  • the transceiver 420 performs steps S10 and S60. More details when the processor 410 and the transceiver 420 perform the above steps can be found in the relevant descriptions of the various embodiments of the above methods and the accompanying drawings, and are not repeated here.
  • the OLT 400 has the corresponding beneficial effects as in the foregoing method embodiments, which will not be repeated here.
  • OLT 400 may also include other devices, which will not be repeated here.
  • the present invention also provides an ONU 300 as described in the above embodiments.
  • the ONU 300 includes a processor 310 and a transceiver 320 .
  • the transceiver 320 includes an optical transmitter and an optical receiver.
  • the optical transmitter converts the electrical signal into an optical signal and sends the optical signal to the ODN
  • the optical receiver receives the optical signal from the ODN network and converts the optical signal into an electrical signal.
  • the light transmitter can be realized by a light-emitting device, such as a gas laser, a solid-state laser, a liquid laser, a semiconductor laser, a directly modulated laser, and the like.
  • the optical receiver may be implemented by a photodetector, such as a photodetector or a photodiode (eg, an avalanche diode) or the like.
  • the transceiver 320 can be an optical module.
  • the optical module includes an optical component and a control circuit.
  • the transceiver 320 can also be an optical component.
  • Optical components include optical transmitters and optical receivers.
  • the optical assembly may include an optical transmitter and an optical receiver for receiving service light and test light.
  • the optical component may also include an optical transmitter and two optical receivers, wherein one optical receiver is used for receiving service light, and the other optical receiver is used for receiving test light.
  • the processor 310 is used to implement functions such as management of the ONU 300, DBA (Dynamic Bandwidth Allocation, dynamic bandwidth allocation), registration of the ONU 300, and data sending and receiving.
  • the processor 310 can be implemented by a hardware circuit, by a software program, or by a combination of hardware and software, such as a Field-Programmable Gate Array (FPGA), or a dedicated integrated chip (Application Specific Integrated Circuit (ASIC) or System on Chip (SoC), or Media Access Control (MAC), or Central Processor Unit (CPU), or Network Processor (NP) ), or a digital signal processing circuit (Digital Signal Processor, DSP), or a microcontroller (Micro Controller Unit, MCU), or a programmable controller (Programmable Logic Device, PLD) or other integrated chips.
  • the processor 310 may perform the above-mentioned determination of the received power values of the test light and service light, generation of feedback information and service light information, and the like.
  • the ONU 300 may further include a memory 330, which may be a read-only memory (Read Only Memory, ROM), a static storage device, a dynamic storage device, or a random access memory (Random Access Memory, RAM), or a register, or a non-volatile storage device. Volatile memory (non-volatile memory), such as flash memory, or at least one disk storage.
  • ROM Read Only Memory
  • RAM Random Access Memory
  • Volatile memory non-volatile memory
  • program codes for implementing the technical solutions provided by the embodiments of the present invention are stored in the memory 330 and executed by the processor 310 .
  • the memory 330 and the processor 310 may be located on different physical entities, or may be partially or fully integrated into one physical entity, and the physical entity may be a Field-Programmable Gate Array (FPGA), or Application Specific Integrated Circuit (ASIC) or System on Chip (SoC), or Central Processor Unit (CPU), or Network Processor (NP), or digital signal processing circuit (Digital Signal Processor, DSP), or microcontroller (Micro Controller Unit, MCU), or programmable controller (Programmable Logic Device, PLD) or other integrated chips.
  • FPGA Field-Programmable Gate Array
  • ASIC Application Specific Integrated Circuit
  • SoC System on Chip
  • CPU Central Processor Unit
  • NP Network Processor
  • DSP Digital Signal Processor
  • MCU Micro Controller Unit
  • PLD programmable controller
  • the ONU 300 also includes a wavelength division multiplexing (WDM) device 340 .
  • the wavelength division multiplexer 340 is connected to the transceiver 320 .
  • the ONU 300 shown in FIG. 21 executes steps S20 , S30 , S40 , and S50 in the embodiment shown in FIG. 19 .
  • the processor 310 executes steps S30 and S40.
  • the transceiver 320 performs steps S20 and S50. More details when the processor 310 and the transceiver 320 perform the above steps can be found in the related descriptions of the various embodiments of the above methods and the accompanying drawings, and are not repeated here.
  • the ONU 300 has the beneficial effects corresponding to those in the above method embodiments, which are not repeated here.
  • the ONU 300 described above may also include other devices, which will not be repeated here.
  • the present invention also provides a PON system, where the PON system includes the OLT400, the ONU300 and the ODN described in the above embodiments.
  • the PON system includes the OLT400, the ONU300 and the ODN described in the above embodiments.
  • the PON system has the beneficial effects corresponding to those in the above-mentioned embodiments, which will not be repeated here.
  • the above-mentioned embodiments it may be implemented in whole or in part by software, hardware, firmware or any combination thereof.
  • software it can be implemented in whole or in part in the form of a computer program product.
  • the computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated.
  • the computer may be a general purpose computer, special purpose computer, computer network, or other programmable device.
  • the computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server, or data center is by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.).
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media.
  • the usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), among others.

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Abstract

一种分光器、ODN、识别ONU所在光链路的方法、OLT、ONU和PON系统。分光器包括入光段和N个出光段，至少N-1个出光段中的每个出光段上设有至少一个光滤波结构，每一光滤波结构以特定的透射率过滤一种波长的光信号；设有光滤波结构的任意两个出光段至少满足以下条件之一：条件1，过滤的至少一种波长不同；条件2，对至少一种波长的光信号的透射率不同。设有光滤波结构的出光段中，存在至少两个出光段满足条件2。将分光器应用于PON的ODN中，可以通过过滤的光信号的波长或透射率来识别出光段，因此在OLT侧发送测试光检测ONU所在光链路时，能够减少测试光的种类，减小OLT的测试光波长扫描范围，降低OLT的发送测试光的器件的制作难度和成本。

Description

分光器、ODN、识别ONU所在光链路的方法、OLT、ONU和PON系统
本申请要求于2020年6月30日提交中国国家知识产权局、申请号为202010614699.6、申请名称为“分光器、ODN、识别ONU所在光链路的方法、OLT、ONU和PON系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及光通信领域，并且更具体地，涉及一种分光器、ODN、识别PON系统中ONU所在光链路的方法、OLT、ONU和PON系统。
背景技术
在无源光网络(passive optical network，PON)系统中，通常包括光线路终端(optical Line Termination，OLT)、光分布网络(optical distribution network，ODN)和光网络单元(optical network unit，ONU)，ODN为OLT和ONU之间提供光传输物理通道。
ODN一般包括光配线架(Optical Distribution Frame，ODF)、光缆接头盒(也称作分光熔接盒(splitting and splicing closure,SSC))、光缆交接箱(也称作光纤分配终端(fiber distribution terminal，FDT))、光纤分纤箱(也称作光纤接入终端(fiber access terminal,FAT))、光纤终端盒(也称作接入终端盒(access terminal box,ATB))等，其中FDT可以包括分光器1，FAT可以包括分光器2。从OLT出来的光信号依次经由ODF、SSC、FDT中的分光器1进行分光、FAT中的分光器2进行分光、以及经由ATB后到达ONU，即从OLT出来的光信号经由OLT与该ONU之间的光链路传输至ONU。其中，分光器1将接收到的光信号功率等分，其中一个支路传输至分光器2，然后分光器2再将接收到的光信号功率等分，各个支路分别传输至所连接的ONU。其中，ODN中最后一级分光器的输出端作为ODN的输出端口，ONU连接至ODN的输出端口。
然而，运营商或局端(Central Office，CO)无法获知每个ONU具体连接至ODN的哪一个输出端口，即无法获知每个ONU具体位于哪一个光链路上，或者，需要安装人员去现场记录，才能确定每个ONU具体连接到哪一个ODN的输出端口(即ONU具体位于哪一个光链路上)，不仅容易出错，而且效率低下，人力成本较高。
发明内容
有鉴于此，本申请提供了一种分光器、ODN、识别PON系统中ONU所在光链路的方法、OLT、ONU和PON系统，旨在快速且准确地检测ONU所在的光链路，提高确定ONU所在光链路的效率。
第一方面，提供了一种分光器，该分光器包括：入光段和N个出光段，N为大于或等于2的整数；至少N-1个出光段中的每个出光段上设有至少一个光滤波结构，每一光滤波结构以特定的透射率过滤一种波长的光信号；设有光滤波结构的任意两个出光段满足以下条件1和条件2中的至少一个：条件1：过滤的至少一种波长不同；条件2：对至少一种波长的光信号的透射率不同。其中，存在至少两个所述出光段满足所述条件2。将该分光器应用于PON的ODN中，由于两个出光段之间过滤的光信号的波长可以不同，或者对同一种光信号的透 射率不同，因此不仅可以通过过滤的光信号的波长来区分出光段，还可以结合对同一种光信号的透射率来区分出光段，因此在OLT侧发送测试光检测ONU所在光链路时，能够很大程度上减少测试光的种类，节约波长资源，减小OLT的测试光波长扫描范围，降低OLT的发送测试光的器件的制作难度和成本，易于实现。
根据上述第一方面，在第一种可能的实现方式中，上述N个出光段中，存在一个未设置所述光滤波结构的出光段，还存在至少一个设置一个所述光滤波结构的出光段。
根据上述第一方面以及第一种可能的实现方式，在第二种可能的实现方式中，上述N个出光段中，至少一个所述出光段上设有M个所述光滤波结构，每一个所述出光段过滤M种波长的光信号，M为大于或等于2的整数。
根据上述第一方面以及第一种可能的实现方式，在第三种可能的实现方式中，每一个所述出光段上最多设置一个所述光滤波结构。
各个出光段通过光过滤结构的数量、过滤的波长、以及对应的透射率来区分，多种组合方式，进一步减少了测试光种类，同时扩大了透射率间隔。
根据上述第一方面以及上述任意一种可能的实现方式，在第四种可能的实现方式中，所述分光器为等比分光器或不等比分光器。
在为不等比分光器时，所述不等比分光器的N个所述出光段包括1个不等比出光段和N-1个等比出光段，所述不等比出光段上可以不设置光滤波结构。
或者不等比出光段上也可以设置一个所述光滤波结构，或者还可以设置至少两个光滤波结构。所述不等比出光段与任一所述等比出光段之间满足：不存在能够过滤相同波长的所述光滤波结构。通过将不等比出光段过滤的波长与等比出光段过滤的波长区分开，因此不等比出光段过滤的波长不会与等比出光段过滤的波长相互影响，进而该ODN中可以设置更多级别的分光器，均可以实现识别ONU所在的光链路。
在为等比分光器时，所述分光器可以为平面光波导PLC分光器，所述PLC分光器包括入光端光纤、N根出光端光纤、和平面光波导；所述平面光波导包括入光波导端、N个出光波导端、以及连接于所述入光波导端和所述N个出光波导端之间的中间分支波导；所述入光端光纤与所述入光波导端连接，所述入光段包括所述入光端光纤与所述入光波导端；所述N根出光端光纤与所述N个出光波导端一一对应连接；每一所述出光段包括所述中间分支波导、一对相互连接的所述出光波导端和所述出光端光纤。所述光滤波结构设置在所述中间分支波导、所述出光波导端、和所述出光端光纤中的至少一种。
所述出光端光纤包括带纤，所述光滤波结构设置在所述带纤上，更加便于制作光滤波结构，制备简单，例如可以集中刻蚀光栅，降低成本。
所述分光器还包括固定盒体，所述固定盒体用于将所述带纤上设有所述光滤波结构的部分封装固定在所述固定盒体内部。固定盒体能够将带纤上设有光栅的部分尽量拉直固定，并且悬空设置，使得光栅尽量减少外界环境因素的影响，如人为拉拽、风吹等长产生的应力对光栅周期产生的影响，起到保护光栅的作用
分光器还可以为熔融拉锥分光器，所述熔融拉锥分光器包括入光端光纤、耦合区光纤和N根出光端光纤，所述光滤波结构设置在所述出光端光纤上。
根据上述第一方面以及任意一种可能的实现方式，在另一种可能的实现方式中，光滤波结构为一段光栅，或者所述光滤波结构为滤光膜。
第二方面，提供了一种光分配网络ODN，该ODN包括一级分光器和二级分光器；所述一级分光器为上述第一方面任一项所述的分光器，且所述一级分光器的入光段称为第一入光 段，所述一级分光器的出光段称为第一出光段；所述二级分光器为上述第一方面任一项所述的分光器，且所述二级分光器的入光段称为第二入光段，所述二级分光器的出光段称为第二出光段；一所述第一出光段与一所述第二入光段连接；所述第一入光段、一对相互连接的所述第一出光段和所述第二入光段、以及一所述第二出光段形成一条光链路；任意两条所述光链路满足以下条件1和条件2中的至少一个：条件1，过滤的至少一种所述波长不同；条件2，对至少一种所述波长的光信号的透射率不同。其中，存在至少两条光链路满足条件2。由于两个出光段之间过滤的光信号的波长可以不同，或者对同一种光信号的透射率不同，因此不仅可以通过过滤的光信号的波长来区分出光段，还可以结合对同一种光信号的透射率来区分出光段，因此在OLT侧发送测试光检测ONU所在光链路时，能够很大程度上减少测试光的种类，节约波长资源，减小OLT的测试光波长扫描范围，降低OLT的发送测试光的器件的制作难度和成本，易于实现。
根据第二方面，在所述ODN的第一种可能的实现方式中，所述一级分光器和所述二级分光器均为等比分光器，所述二级分光器为多个，且各个所述二级分光器为相同的分光器，任一一级分光器与任一二级分光器为不同的分光器。二级分光器为相同的分光器，可以极大减少ODN中的分光器的种类，一是降低制造商的生产成本，二是便于施工人员安装，安装过程中不容易出错。
根据第二方面以及第一种可能的实现方式，在所述ODN的第二种可能的实现方式中，任一所述第一出光段和任一所述第二出光段满足：不存在能够过滤相同波长的所述光滤波结构。因此对于任意一条光链路，同一种波长的光信号只存在一个光滤波结构以特定的透射率进行过滤，不同级别的分光器不会对同一种波长的光信号的过滤进行叠加，各个级别的分光器在过滤光信号时互不影响，进而该ODN中可以设置多个级别的分光器，如四个甚至更多级别的分光器等，均可以识别ONU所在的光链路。
根据第二方面以及上述任意一种可能的实现方式，在所述ODN的第三种可能的实现方式中，所述一级分光器与所述二级分光器均为不等比分光器；所述不等比分光器的出光段包括1个不等比出光段和N-1个等比出光段；所述一级分光器的所述不等比出光段与所述二级分光器的所述入光段连接。所述一级分光器与所述二级分光器为相同的不等比分光器。因此可以使得该ODN中仅包括一种类型的不等比分光器，ODN中分光器类型越少，越有利于降低成本，安装过程中不容易出错。
第三方面，提供了一种识别无源光网络PON系统中光网络单元ONU所在光链路的方法，包括：OLT下行发送Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与第一ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；所述OLT接收所述第一ONU反馈的反馈信息，所述反馈信息用于指示所述测试光的接收功率值；所述OLT根据至少一种波长的测试光的接收功率值确定透射率；所述OLT根据光链路与波长、透射率之间的关系，以及所述至少一种波长和确定的所述透射率，确定所述第一ONU位于所述第一光链路。由于OLT与第一ONU之间的第一光链路透射光信号时将波长和透射率结合起来，因此在OLT侧发送测试光检测ONU所在光链路时，能够很大程度上减少测试光的种类，节约波长资源，减小OLT的测试光波长扫描范围，降低OLT的发送测试光的器件的制作难度和成本，易于实现。
根据第三方面，在第三方面的第一种实现方式中，Q大于或等于2，所述OLT下行发送Q种波长的测试光包括：所述OLT按时序依次下行发送所述Q种波长的测试光；其中，所述OLT每次下行发送一种波长的所述测试光之后，等待接收所述第一ONU反馈的所述反馈信 息；所述OLT在接收到所述反馈信息之后，再下行发送下一种波长的所述测试光。该方式不需要占用额外的信息来指示波长，直接根据时序即可判断波长。不需要额外改动信息格式。
根据第三方面，在第三方面的第二种实现方式中，所述OLT下行发送的所述Q种波长的测试光中的每一种测试光中均携带标签，其中，任意两种波长的测试光携带的所述标签不同；所述反馈信息用于指示所述测试光的接收功率值以及该测试光中携带的所述标签；所述方法还包括：所述OLT根据所述标签确定所述接收功率值对应的所述测试光的波长。该方式中，OLT发送测试光以及ONU发送反馈信息不受时序限制，实现起来比较灵活。
根据第三方面以及以上任意一种实现方式，在第三方面的第三种实现方式中，所述方法还包括：所述OLT将接收到的多个接收功率值中的最大值确定为基准接收功率值；所述OLT根据至少一种波长的测试光的接收功率值确定透射率包括：所述OLT根据所述至少一种波长的测试光的接收功率值与所述基准接收功率值，确定所述至少一种波长的测试光在所述第一光链路的透射率。或者，所述方法还包括：所述OLT下行发送业务光信号；所述OLT接收所述第一ONU反馈的业务光信息，所述业务光信息用于指示所述业务光信号的业务光接收功率值；所述OLT根据所述至少一种波长的测试光的接收功率值与所述业务光接收功率值，确定所述至少一种波长的测试光在所述第一光链路的透射率。
根据第三方面以及以上任意一种实现方式，在第三方面的第四种实现方式中，所述方法还包括：所述OLT发送光链路信息，所述光链路信息用于指示所述第一光链路。所述光链路信息包括所述各级分光器中每个所述分光器的标识信息，以及位于所述第一光链路上的每一所述端口的标识信息。
根据第三方面以及以上任意一种实现方式，在第三方面的第五种实现方式中，所述PON系统包括光分配网络ODN，所述ODN为如上述的ODN。
第四方面，提供了一种识别无源光网络PON系统中光网络单元ONU所在光链路的方法，包括：光网络单元ONU接收光线路终端OLT发送的Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与所述ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；所述ONU确定接收的每一种波长的所述测试光的接收功率值；所述ONU向所述OLT发送反馈信息，所述反馈信息用于指示所述测试光的接收功率值。由于OLT与ONU之间的第一光链路透射光信号时将波长和透射率结合起来，因此在OLT侧发送测试光检测ONU所在光链路时，能够很大程度上减少测试光的种类，节约波长资源，减小OLT的测试光波长扫描范围，降低OLT的发送测试光的器件的制作难度和成本，易于实现。
根据第四方面，在第三方面的第一种实现方式中，Q大于或等于2，所述ONU接收OLT发送的Q种波长的测试光包括：所述ONU按照时序依次接收OLT发送的Q种波长的测试光；其中，所述ONU接收到一种波长的所述测试光之后，向所述OLT发送反馈信息，所述反馈信息用于指示所述一种波长的所述测试光的接收功率值；并在发送所述反馈信息之后，所述ONU接收下一种波长的所述测试光。该方式不需要占用额外的信息来指示波长，直接根据时序即可判断波长。不需要额外改动信息格式。
根据第四方面，在第四方面的第二种实现方式中，所述ONU接收的所述Q种波长的测试光中的每一种测试光中均携带标签，其中，任意两种波长的测试光携带的所述标签不同；所述ONU向所述OLT发送确定的每一种波长的所述测试光的接收功率值包括：所述ONU向所述OLT发送反馈信息，所述反馈信息用于指示所述测试光的接收功率值以及指示该测试光中携带的所述标签。该方式中，OLT发送测试光以及ONU发送反馈信息不受时序限制，实现起来比较灵活。
根据第四方面以及以上任意一种实现方式，在第四方面的第三种实现方式中，所述方法还包括：所述ONU接收所述OLT发送的业务光信号；所述ONU确定所述业务光信号的业务光接收功率值；所述ONU向所述OLT发送业务光信息，所述业务光信息用于指示所述业务光信号的业务光接收功率值。
根据第四方面以及以上任意一种实现方式，在第四方面的第四种实现方式中，所述PON系统包括光分配网络ODN，所述ODN为上述的ODN。
第五方面，提供了一种OLT，所述OLT包括收发器和处理器；所述收发器用于下行发送Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与第一ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；所述收发器还用于接收所述第一ONU反馈的反馈信息，所述反馈信息用于指示所述测试光的接收功率值；所述处理器用于根据至少一种波长的测试光的接收功率值确定透射率；所述处理器还用于根据光链路与波长、透射率之间的关系，以及所述至少一种波长和确定的所述透射率，确定所述第一ONU位于所述第一光链路。由于OLT与第一ONU之间的第一光链路透射光信号时将波长和透射率结合起来，因此在OLT侧发送测试光检测ONU所在光链路时，能够很大程度上减少测试光的种类，节约波长资源，减小OLT的测试光波长扫描范围，降低OLT的发送测试光的器件的制作难度和成本，易于实现。
根据第五方面，在第五方面的第一种实现方式中，Q大于或等于2，所述收发器按时序依次下行发送所述Q种波长的测试光；其中，所述收发器每次下行发送一种波长的所述测试光之后，等待接收所述第一ONU反馈的所述反馈信息；所述收发器在接收到所述反馈信息之后，再下行发送下一种波长的所述测试光。该方式不需要占用额外的信息来指示波长，直接根据时序即可判断波长。不需要额外改动信息格式。
根据第五方面及第五方面的第一种实现方式，在第五方面的第二种实现方式中，所述收发器还用于发送光链路信息，所述光链路信息用于指示所述第一光链路，所述光链路信息包括所述各级分光器中每个所述分光器的标识信息，以及位于所述第一光链路上的每一所述端口的标识信息。
第六方面，提供一种ONU，所述ONU包括收发器和处理器；所述收发器用于接收光线路终端OLT发送的Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与所述ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；所述处理器用于确定接收的每一种波长的所述测试光的接收功率值；所述收发器还用于向所述OLT发送反馈信息，所述反馈信息用于指示所述测试光的接收功率值。由于OLT与ONU之间的第一光链路透射光信号时将波长和透射率结合起来，因此在OLT侧发送测试光检测ONU所在光链路时，能够很大程度上减少测试光的种类，节约波长资源，减小OLT的测试光波长扫描范围，降低OLT的发送测试光的器件的制作难度和成本，易于实现。
根据第六方面，在第六方面的第一种实现方式中，Q大于或等于2，所述收发器按照时序依次接收OLT发送的Q种波长的测试光；其中，所述收发器接收到一种波长的所述测试光之后，向所述OLT发送反馈信息，所述反馈信息用于指示所述一种波长的所述测试光的接收功率值；并在发送所述反馈信息之后，所述收发器接收下一种波长的所述测试光。该方式不需要占用额外的信息来指示波长，直接根据时序即可判断波长。不需要额外改动信息格式。
根据第六方面及第六方面的第一种实现方式，在第六方面的第二种实现方式中，所述收发器还用于接收所述OLT发送的业务光信号；所述处理器还用于确定所述业务光信号的业务光接收功率值；所述收发器还用于向所述OLT发送业务光信息，所述业务光信息用于指示所 述业务光信号的业务光接收功率值。
第七方面，提供一种无源光网络PON系统，所述PON系统包括上述的光线路终端OLT，上述的光网络单元ONU，以及上述的光分配网络ODN。
本申请的又一方面，提供了一种计算机可读存储介质，所述计算机可读存储介质中存储有上述第三方面及其任一实现方式所述的OLT所用的相应的计算机软件指令，当其在计算机上运行时，使得计算机执行上述各方面所述的相应方法步骤。
本申请的又一方面，提供了一种计算机可读存储介质，所述计算机可读存储介质中存储有上述第四方面及其任一实现方式所述的ONU所用的相应的计算机软件指令，当其在计算机上运行时，使得计算机执行上述各方面所述的相应方法步骤。
附图说明
图1(1)为本发明一实施例中PLC分光器的结构示意图；
图1(2)为本发明另一实施例中PLC分光器的结构示意图；
图1(3)为本发明又一实施例中PLC分光器的结构示意图；
图1(4)为本发明再一实施例中PLC分光器的结构示意图；
图2为本发明一实施例中固定盒体与带纤的固定示意图；
图3(1)为为本发明一实施例中FBT分光器的结构示意图；
图3(2)为为本发明另一实施例中FBT分光器的结构示意图；
图4为本发明中光滤波结构以特定的透射率过滤一种波长的光信号的一示例图；
图5为本发明一实施例中不等比分光器的结构示意图；
图6为ODN一实现方案的示例图；
图7为本发明一实施例PON系统中ODN的一示意图；
图8为本发明一实施例PON系统中ODN的另一示意图；
图9为本发明一实施例PON系统中ODN的另一示意图；
图10为本发明一实施例PON系统中ODN的另一示意图；
图11为本发明一实施例PON系统中ODN的另一示意图；
图12为本发明一实施例PON系统中ODN的另一示意图；
图13为本发明一实施例PON系统中ODN的另一示意图；
图14为本发明一实施例PON系统中ODN的另一示意图；
图15为本发明一实施例PON系统中ODN的另一示意图；
图16为本发明一实施例PON系统中ODN的另一示意图；
图17为本发明一实施例PON系统中ODN的另一示意图；
图18为本发明一实施例PON系统中ODN的另一示意图；
图19为本发明一实施例识别PON系统中ONU所在光链路的方法的流程示意图；
图20为本发明一实施例中OLT的结构示意图；
图21为本发明一实施例中ONU的结构示意图。
具体实施方式
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的术语在适当情况下可以互换，以便这里描述的实施例能够以除了在这里图示或描述的内容以外的顺序实施。此外， 术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列产品或设备不必限于清楚地列出的那些结构，而是可包括没有清楚地列出的或对于这些产品或设备固有的其它结构，本申请中所出现的结构的举例，仅仅是一种逻举例说明，实际应用中实现时可以有另外替换的结构，例如多个部件可以结合成或集成在另一个结构中，或一些结构特征可以忽略，或不执行，另外，所显示的或讨论的相互之间的耦合或直接耦合，可以根据实际的需要选择其中的部分或全部结构来实现本发明实施例方案的目的。
下面将结合本发明实施例中的附图，对本发明实施例的技术方案进行描述。
本申请实施例提供一种分光器，该分光器也可以称为分光器模块、光分路器等。该分光器用于将一路光信号分为多路光信号。该分光器可以用在需要分光的场景，例如用在光分配网络(optical distribution network，ODN)中。以分光器用在ODN中为例，分光器可以设置在分光装置中，分光装置例如可以是ODF、SSC、FDT、FAT、CBT(connectorised block terminal)、ATB等设备，也可以是ODN中的其他设备。
在一实施例中，参照图1(1)、图1(2)、图1(3)、图1(4)、图3(1)和图3(2)，图1(1)至图1(4)为本发明实施例中平面光波导分光器的结构示意图，图3(1)和图3(2)为本发明实施例中熔融拉锥分光器的结构示意图。分光器包括入光段100和N个出光段200，N为大于或等于2的整数，光信号经由入光段100进入，并从N个出光段200输出。至少N-1个出光段200中的每个出光段200上设有至少一个光滤波结构210，每一个光滤波结构以特定的透射率过滤一种波长的光信号，也可以理解为光滤波结构210以特定的透射率过滤一种中心波长的光信号。可以理解的是，光滤波结构210过滤的是一段波长范围的光信号，该段波长的光信号具有中心波长，在中心波长上透射率达到最小值。如图4所示，图4为光滤波结构210以特定的透射率过滤一种波长的光信号的示意图，横坐标表示波长，纵坐标表示透射率。假设图4中在中心波长1上透射率达到最小值20％，则可以理解为光滤波结构210以特定的透射率过滤波长1(或中心波长1)的光信号。
上述光滤波结构210以特定的透射率过滤一种波长的光信号，其中的特定的透射率最小值可以为0，最大值小于100％。
其中，设有光滤波结构210的任意两个出光段200至少满足以下条件1和条件2中的至少一个：条件1，过滤的至少一种波长不同；条件2，对至少一种波长的光信号的透射率不同。可以理解的是，设有光滤波结构210的任意两个出光段200之间可以仅满足条件1，或者也可以仅满足条件2，或者还可以同时满足条件1和条件2。
在一实施例中，设有光滤波结构210的出光段200中，存在至少两个出光段200满足条件2。条件2可以理解为，对同一种波长的光信号的透射率不同。例如，存在一个出光段200对波长1的光信号的透射率为30％，还存在一个出光段200对波长1的光信号的透射率为70％，则认为这两个出光段200满足条件2。
在一实施例中，入光段100为分光器中用于传输上述一路光信号的光路。分光器内部将一路光信号分为N路光信号，出光段200为入光段100之后的光路。
在一实施例中，分光器的入光段100的数量可以为1个，也可以为至少2个。以2个入光段100为例，在分光器用于ODN网络时，其中一个入光段100连接主路光纤，另一个入光段100连接备用光纤。
在一实施例中，如图1(1)至图1(4)所示，分光器为平面光波导(planar lightwave circuit,PLC)分光器，PLC分光器包括入光端光纤110、N根出光端光纤221、和平面光波导230。PLC分光器还可以包括衬底240，平面光波导230设于衬底240上。平面光波导230包括入 光波导端120、N个出光波导端231、以及连接于入光波导端和N个出光波导端231之间的中间分支波导232。入光端光纤110与入光波导端连接。N根出光端光纤221与N个出光波导端231一一对应连接。PLC分光器还可以包括粘合剂250，用于将入光端光纤110与入光波导端连接，以及将出光端光纤221与出光波导端231连接。其中，上述入光段100包括入光端光纤110与入光波导端。每一出光段200包括中间分支波导232、一对相互连接的出光波导端231和出光端光纤221。可以理解的是，每一个出光段200包括中间分支波导232的一部分，例如，图1(1)所示的第一个出光段200中的中间分支波导232包括M21,M31；第二个出光段200中的中间分支波导232包括M21,M32。在一实施例中，N根出光端光纤221的端部形成光纤阵列220，衬底240和波导形成分光器芯片，分光器芯片和光纤阵列220通过粘合剂250粘接在一起，并且使得N个出光波导端231与N根出光端光纤221一一对应连接。
在另一实施例中，如图3(1)和图3(2)所示，分光器为熔融拉锥(Fused biconical taper，FBT)分光器，FBT分光器包括入光端光纤110、耦合区光纤270和N个出光端光纤221。FBT分光器是将两根或多根光纤捆在一起，然后在拉锥机上熔融拉伸，并实时监控分光比的变化，分光比达到要求后结束熔融拉伸，其中输入端保留一根光纤，其余光纤剪掉，保留的一根光纤作为入光端光纤110，输出端的各路光纤作为N个出光端光纤221。其中，入光段100可以包括上述入光端光纤110，出光段200可以包括上述N个出光端光纤221。
在一实施例中，一个光滤波结构210为一段光栅，一段光栅以特定的透射率过滤一种波长的光信号。
上述光栅是一种通过一定方法使出光段200的折射率发生轴向周期性调制而形成的衍射光栅。上述光栅可以为光纤光栅(即光栅形成在光纤上)，也可以为波导光栅(即光栅形成在波导上)。光纤光栅可以为光纤布拉格光栅(fiber bragg grating,FBG)，也可以为长周期光栅(long period fiber grating，LPFG)。
以光纤光栅为例，一般是利用光纤材料的光敏性，通过紫外光曝光的方法将入射光相干场图样写入纤芯，在纤芯内产生沿纤芯轴向的折射率周期性变化，从而形成永久性空间的相位光栅。另外，光纤光栅还可以通过飞秒激光器、二氧化碳激光器等制作。对于波导上的光栅，也可以采用上述光纤光栅的制备方法。
一段光栅可以被看作为特定中心波长的带阻滤波器。当一束宽光谱的光信号经过光栅时，特定中心波长的光信号产生全部反射，其余波长的光信号将透过光栅继续传输；或者，光栅以一定的透射率过滤特定中心波长的光信号，即特定中心波长的光信号部分反射，并且特定中心波长的光信号部分透过光栅继续传输，其余波长的光信号将透过光栅继续传输。
可以理解的是，光栅过滤的是一段波长范围的光信号，该段波长的光信号具有上述中心波长。
其中，上述中心波长和透射率可以在制作光栅过程中，调整光栅周期、光栅栅距和曝光时间来控制。
在另一实施例中，上述光滤波结构210还可以为滤光膜。滤光膜可以为镀在波导或光纤上的薄膜。例如，可以在波导的端面镀膜，或者在波导上开口后镀膜，或者在光纤的端面上镀膜，或者在光纤上开口后镀膜。每一个出光段200上的滤光膜的数量、位置等设置方式均可以参照上述光栅的相应描述，在此不再赘述。可以理解的是，滤光膜过滤的是一段波长范围的光信号，该段波长的光信号具有上述中心波长。
各个出光段200上设置的光滤波结构210的数量可以有多种实施方式：
在一实施例中，每一个出光段200上最多设置一个光滤波结构210，光滤波结构210数 量越少，分光器的生产工艺越简单，制作难度越小，有利于降低成本。其中包括两种情况：情况一，N个出光段200中的每一个均设有1个光滤波结构210，每个出光段200过滤一种波长的光信号，即每个出光段200上的光滤波结构210过滤一种波长的光信号。情况二，N个出光段200中，存在一个未设置光滤波结构210的出光段200，其余N-1个出光段200中的每一个均设有1个光滤波结构210。
在另一实施例中，至少一个出光段200上设有M个光滤波结构210，每一个出光段200过滤M种波长的光信号，M为大于或等于2的整数。例如，N＝8，每个出光段200均设置2个光滤波结构210，或者，部分出光段200设置1个光滤波结构210，其余出光段200均设置2个光滤波结构210。
在另一实施例中，N个出光段200中，存在一个未设置光滤波结构210的出光段200。其余各个出光段200设置至少1个光滤波结构210。进一步的，情况一：N个出光段200中，还存在至少一个设置一个光滤波结构210的出光段200，例如，N＝8，其中1个出光段200未设置光滤波结构210，其余7个出光段200均设置1个光滤波结构210或者均设置2个光滤波结构210。情况二：N个出光段200中，还存在至少一个设置一个所述光滤波结构210的出光段200，同时还存在至少一个设置至少两个光滤波结构210的出光段200，例如，N＝8，其中1个出光段200未设置光滤波结构210，2个出光段200设置均设置1个光滤波结构210，其余5个出光段200均设置至少2个光滤波结构210。情况三：N个出光段200中，还存在至少一个设置至少两个所述光滤波结构210的出光段200，例如，N＝8，其中1个出光段200未设置光滤波结构210，其余7个出光段200均设置至少两个光滤波结构210。
在一实施例中，对于PLC分光器，光滤波结构210设置在中间分支波导232、出光波导端231(如图1(2)所示)、和出光端光纤221(如图1(1)、图1(3)和图1(4)所示)中的至少一种。
在一实施例中，如图1(3)和图1(4)，出光端光纤221包括光纤阵列220上的光纤222、带纤223、和尾纤224等。如图1(4)，分光器还包括分支器225，分支器225一端连接带纤223，另一端连接尾纤224，且带纤223位于分支器225与光纤阵列220上的光纤222之间。光滤波结构210设置在出光端光纤221包括：光滤波结构210设置在光纤阵列220上的光纤222(如图1(1))、带纤223(如图1(3))和尾纤中的至少一种上。
在一实施例中，如图1(2)，一个出光段200上的M个光滤波结构210全部设置在出光波导端231上；或者也可以全部设置在出光端光纤221上。如图1(1)所示，一个出光段200上的M个光滤波结构210全部设置在光纤阵列220上的光纤222上；或者如图1(3))所示，一个出光段200上的M个光滤波结构210全部设置在带纤223上；或者如图1(4))所示，一个出光段200上的M个光滤波结构210全部设置在尾纤224上。或者，一个出光段200上的M个光滤波结构210也可以分散设置在出光波导端231、出光端光纤221(包括光纤阵列220上的光纤222、带纤223和尾纤224)和中间分支波导232中的至少两种上。
在一实施例中，对于FBT分光器，光滤波结构210设置在出光端光纤221上。
在一实施例中，以所有光滤波结构210为光栅，且光栅全部设置在带纤223上为例，如图1(3)和图2所示，分光器还包括固定盒体260，用于将带纤223上设有光栅的部分封装固定在固定盒体260内部。其中，固定盒体260能够将带纤223上设有光栅的部分尽量拉直固定，并且悬空设置，使得光栅尽量减少外界环境因素的影响，如人为拉拽、风吹等长产生的应力对光栅周期产生的影响，起到保护光栅的作用。如图2为固定盒体260与带纤223的固定示意图，带纤223的中间部分被剥去带纤223套管，裸露出光纤，裸露的光纤上刻有光栅， 固定盒体260相对的两端分别将带纤223固定，使得带纤223中间裸露的光纤被拉直固定。固定盒体260可以通过固定胶来固定带纤223，或者也可以通过卡接等方式固定。
可以理解的是，光滤波结构210为滤波膜时，也可以采用如图1(1)至图1(4)的方式，同样可以达到上述有益效果，在此不再赘述。
可以理解的是，上述入光端光纤110，是指分光器的支路较少的那一端的光纤。上述出光端光纤221，是指分光器的支路较多的各端的光纤。光信号可以从入光端光纤110进入，经由分光器分为多路光信号，并通过各个出光端光纤221输出。光信号也可以从出光端光纤221进入，经由入光端光纤110输出。
在一实施例中，分光器为等比分光器。等比分光器的N个出光段200输出的光信号的功率相同或大体相同。如图1(1)至图1(4)所示，等比分光器可以为PLC分光器。如图3(1)和图3(2)所示，等比分光器也可以为FBT分光器。
在另一实施例中，如图5所示，分光器为不等比分光器。不等比分光器的N个出光段200包括1个不等比出光段201和N-1个等比出光段202。各个等比出光段202输出的光信号的功率相同或大体相同。不等比出光段201一般也称为大分支比出光段200，不等比出光段201输出的光信号的功率与各个等比出光段202输出的光信号的功率不同或差异较大。一般情况下，不等比出光段201输出的光信号的功率大于各个等比出光段202输出的光信号的功率。相应的，不等比分光器包括1个不等比出光端光纤221和N-1个等比出光端光纤221。
不等比分光器可以为PLC分光器，也可以为FBT分光器。
或者不等比分光器还可以为PLC和FBT结合的分光器。例如，图5中的1:2分光段可以采用FBT实现，1:8分光段可以采用PLC实现。以图5为例，1:2分光段的两个分支端的输出光功率比为30％:70％，其中1:2分光段的30％分支端连接1:8分光段。
在一实施例中，不等比出光段201设置一个光滤波结构210，不等比出光段201过滤一种波长的光信号。各个等比出光段202中最多存在一个未设置光滤波结构210的等比出光段202。
在一实施例中，不等比出光段201与任一等比出光段202之间满足：不存在能够过滤相同波长的光滤波结构210。例如，不等比出光段201过滤波长1的光信号，一等比出光段202过滤波长1和波长2的光信号，则认为存在能够过滤相同波长的光滤波结构210。不等比出光段201过滤波长1的光信号，一等比出光段202过滤波长2和波长3的光信号，则认为两者之间不存在能够过滤相同波长的光滤波结构210。
在另一实施例中，不等比出光段201未设置光滤波结构210，各个等比出光段202均至少设置一个光滤波结构210。
在另一实施例中，不等比出光段201设置至少两个光滤波结构210。不等比出光段201与任一等比出光段202之间满足：不存在能够过滤相同波长的光滤波结构210。以设置两个光滤波结构210为例，不等比出光段201过滤波长1和波长3的光信号，一等比出光段202过滤波长1和波长2的光信号，则认为存在能够过滤相同波长的光滤波结构210。不等比出光段201过滤波长1和波长3的光信号，一等比出光段202过滤波长2和波长4的光信号，则认为两者不存在能够过滤相同波长的光滤波结构210。
可以理解的是，如果两个出光段200能够过滤的光信号的波长种类数不同，则认为这两个出光段200满足上述条件1。例如，一个出光段200未设置光滤波结构210(即过滤的波长种类数为0)，另一个出光段200设有至少1个光滤波结构210(即过滤的波长种类数为至少1种)，则可以认为满足上述条件1。又例如，一个出光段200设有1个光滤波结构210(即 过滤的波长种类数为1种)，另一个出光段200设有2个光滤波结构210(如过滤的波长种类数为2种)，则可以认为满足上述条件1。
可以理解的是，如果两个出光段200上的光滤波结构210数量相同，且两个出光段200上过滤的波长没有全部相同，则认为这两个出光段200满足上述条件1。例如，一个出光段200过滤的波长为波长1和波长2，另一个出光段200过滤的波长为波长1和波长3，则认为满足上述条件1。又例如，一个出光段200过滤的波长为波长1和波长2，另一个出光段200过滤的波长为波长3和波长4，则认为满足上述条件1。
可以理解的是，如果两个出光段200上均可以过滤波长为波长1的光信号，其中一个出光段200对波长1的光信号的透射率为R1，另一个出光段200对波长1的光信号的透射率为R2，且R1与R2不相同，则认为这两个出光段200满足上述条件2。
在另一实施例中，不等比分光器也可以包括2个或2个以上的不等比出光段201。
本申请实施例还提供一种ODN，该ODN包括一级分光器和二级分光器。
一级分光器和二级分光器为上述各个实施例所述的分光器。
该ODN还可以包括ODF、SSC、FDT、FAT、ATB等，该一级分光器可以设置在FDT、FAT、ODF、SSC等装置中，该二级分光器可以设置在FDT、FAT、ODF、SSC等装置中。一级分光器和二级分光器可以设置在不同类型的装置中，也可以同一种装置中。
可以理解的是，本申请各个实施例中的一级分光器和二级分光器是相对的概念，二级分光器的入光段100直接或间接的连接到一级分光器的出光段200上。如图7所示的ODN，包括四个级别的分光器，分别为分光器11，分光器21，分光器31和分光器41。其中，分光器12的入光段100通过光纤直接连接到分光器11的一出光段200上，则分光器11可以称为一级分光器，分光器12可以称为二级分光器。另外，分光器31的入光段100通过光纤直接连接到分光器21的一出光段200上，则分光器21也可以称为一级分光器，分光器31可以称为二级分光器。另外，分光器31的入光段100间接的通过分光器21连接到分光器11的一出光段200上，则分光器11可以称为一级分光器，同时分光器31可以称为二级分光器。
为了便于描述，以下一级分光器的入光段100称为第一入光段100，一级分光器的出光段200称为第一出光段200；二级分光器的入光段100称为第二入光段100，二级分光器的出光段200称为第二出光段200。
一第一出光段200与一所述第二入光段100连接，可以理解的是，可以直接连接，也可以间接连接。第一入光段100、一对相互连接的第一出光段200和第二入光段100、以及一第二出光段200形成一条光链路。
在一实现方案中，如图6所示，ODN包括1个一级分光器11和8个二级分光器21，8个二级分光器相同，图6中仅示出2个二级分光器，其余二级分光器省略未示出。任意两个第一出光段200过滤的波长不相同，任一第一出光段200与任一第二出光段200过滤的波长不同。因此图6所示ODN中的光链路能够过滤16种波长的光信号。因此在OLT发送测试光信号来识别各个ONU所在光链路的过程中，OLT要发送16种波长的测试光信号。不仅占用了很多波长资源，也导致OLT侧的扫描波长范围过大，成本较高。
在本发明实施例中，如图7-18所示，任意两条光链路满足以下条件1和条件2中的至少一个：条件1：过滤的至少一种波长不同；条件2：对至少一种波长的光信号的透射率不同。条件1和条件2的具体介绍可以参照上述分光器的相关描述，在此不再赘述。
可以理解的是，如果两条光链路能够过滤的光信号的波长种类数不同，则认为这两条光 链路满足上述条件1。例如，一条光链路过滤的波长种类数为0，另一条光链路过滤的波长种类数为至少1种，则可以认为满足上述条件1。又例如，一条光链路过滤的波长种类数为1种，另一条光链路过滤的波长种类数为2种，则可以认为满足上述条件1。
可以理解的是，如果两条光链路能够过滤的光信号的种类数相同，且两条光链路过滤的波长没有全部相同，则认为这两条光链路满足上述条件1。例如，一条光链路过滤的波长为波长1和波长2，另一条光链路过滤的波长为波长1和波长3，则认为满足上述条件1。又例如，一条光链路过滤的波长为波长1和波长2，另一条光链路过滤的波长为波长3和波长4，则认为满足上述条件1。
在一实施例中，存在至少两条光链路满足条件2。例如，存在一个光链路对波长1的光信号的透射率为30％，还存在一个光链路对波长1的光信号的透射率为70％，则认为这两个光链路满足条件2。
本发明中，分光器的任意两个分光段满足上述条件1和条件2中的至少一个，任意两条光链路满足上述条件1和条件2中的至少一个，设有光滤波结构的出光段中，存在至少两个出光段满足条件2，且存在至少两条光链路满足条件2。因此，通过将波长和透射率这两个条件结合起来，能够很大程度上减少测试光的种类，节约波长资源，有利于减小OLT的测试光波长扫描范围，极大降低OLT的发送测试光的器件(如可调激光器)的制作难度和成本，易于实现。
在一实施例中，如图8至14所示，一级分光器和二级分光器均为等比分光器，二级分光器为多个(图8至10仅示出2个二级分光器，其余未示出)，各个二级分光器为相同的分光器，任一一级分光器与任一二级分光器为不同的分光器。因此，即使各个二级分光器为相同的分光器，但由于一级分光器的任意两个第一出光段200至少满足上述条件1和条件2之一，因此仍然能够识别出ONU所在光链路的第一出光段200，即识别出ONU所在光链路上的一级分光器的端口；同时由于二级分光器的任意两个第二出光段200至少满足上述条件1和条件2，因此能够进一步识别出ONU所在光链路的第二出光段200，即识别出ONU所在光链路上的二级分光器的端口。本实施例中，二级分光器为相同的分光器，可以极大减少ODN中的分光器的种类，一是降低制造商的生产成本，二是便于施工人员安装，安装过程中不容易出错。
进一步的，如图8和9所示，任一第一出光段200和任一第二出光段200满足：不存在能够过滤相同波长的光滤波结构210。因此对于任意一条光链路，同一种波长的光信号只存在一个光滤波结构210以特定的透射率进行过滤，不同级别的分光器不会对同一种波长的光信号的过滤进行叠加，各个级别的分光器在过滤光信号时互不影响，进而该ODN中可以设置多个级别的分光器，如四个甚至更多级别的分光器等，均可以识别ONU所在的光链路。
进一步的，在一实施例中，如图9所示，任意两个第一出光段200过滤的波长相同，且任意两个第一出光段200对所过滤的波长的透射率不同。任意两个第二出光段200过滤的波长相同，且任意两个第二出光段200对所过滤的波长的透射率不同。即通过透射率来区分一级分光器的各个端口，以及通过透射率来区分二级分光器的各个端口，通过过滤的波长来区分分光器级别。能够进一步减少测试光的种类，节约波长资源。在另一实施例中，如图8所示，还可以通过波长来区分分光器级别，以及通过波长和透射率的组合来区分分光器端口，不仅能够减少测试光的种类，还能够使得不同端口对同一种波长的透射率间隔尽量大，更有利于识别光链路，提高识别光链路的准确性。
在另一实施例中，如图10所示，还可以通过透射率来区分分光器级别，以及通过波长区 分分光器端口。
为了进一步减少测试光种类，同时使得不同端口对同一种波长的透射率间隔尽量大，如上述分光器的实施例所述，一级分光器的至少一个出光段200上可以设置至少M个光滤波结构210，同样二级分光器的至少一个出光段200上也可以设置至少M个光滤波结构210，M为大于或等于2的整数。以下以一级分光器和二级分光器的每个出光段200上均设置2个光滤波结构210为例，如图11所示，例如一级分光器的出光段2001对波长1的透射率为0％，以及对波长2的透射率为0％；出光段2006对波长1的透射率为40％，以及对波长2的透射率为80％，其余出光段200以及二级分光器对各个波长的透射率同理可参照图11，在此不再赘述，各级分光器过滤的波长种类仅有4种，透射率间隔达到20％至40％。如图12所示，一级分光器和二级分光器过滤的波长种类一共有8种，透射率间隔达到50％。如图13所示，一级分光器和二级分光器过滤的波长种类一共有6种，透射率间隔达到50％。可见，通过增加一个出光段200上设置的光滤波结构210的数量，可以在有效的减少测试光种类的同时，还能够尽可能的扩大不同出光段200对同一种波长的透射率间隔。
在一实施例中，为了进一步减少测试光种类，同时使得不同端口对同一种波长的透射率间隔尽量大，一级分光器的各个出光段200上设置的光滤波结构210数量可以存在不相同的，例如，存在一个未设置光滤波结构210的出光段200，还存在设置1个光滤波结构210的出光段200。如图14，还可以进一步的存在设置2个光滤波结构210的出光段200。各个出光段200通过光过滤结构的数量、过滤的波长、以及对应的透射率来区分，多种组合方式，进一步减少了测试光种类，同时扩大了透射率间隔。二级分光器同上述一级分光器，在此不再赘述。在该实施例中，一级分光器和二级分光器过滤的波长种类一共仅有4种，同时透射率间隔达到50％，有效地实现了减少测试光种类的同时，尽量扩大透射率间隔。
在一实施例中，如图7以及图15-18所示，一级分光器和二级分光器均为不等比分光器。在一个例子中，每一级分光器的数量分别为一个，下一级分光器的入光段100连接至其上一级分光器的不等比出光段201上。可以理解的是，在其他例子中，同一级别的分光器也可以为至少两个。
在一个例子中，各级分光器的不等比出光段201上未设置光滤波结构210。如图7所示，包括3个不等比分光器(如图7中的分光器11,21,31)以及1个等比分光器(如图7中的分光器41)，各级不等比分光器通过波长来区分分光器级别，以及通过透射率区分分光器端口。可以理解的是，在其他实施例中，如图15所示，各级不等比分光器还可以通过透射率来区分分光器级别，以及通过波长区分分光器端口。或者在其他实施例中，如图16所示，各级不等比分光器还可以通过波长来区分分光器级别，以及通过波长和透射率的组合来区分分光器端口。
在另一个例子中，不等比出光段201上设置一个光滤波结构210。各级不等比分光器的不等比出光段201可以过滤相同波长的光信号，也可以过滤不同波长的光信号。各级不等比分光器可以通过波长或透射率或其组合来区分分光器级别，也可以通过波长或透射率或其组合区分分光器端口。还可以如图17和18所示，各个级别的不等比分光器为相同的不等比分光器。如图17，第一级别的分光器11的各个等比出光段202只过滤波长1，第二级别的分光器21的各个等比出光段202以70％的透射率过滤波长2，以及还同时过滤波长1，第三级别的分光器31的各个等比出光段202以70％*70％＝49％的透射率过滤波长2，以及还同时过滤波长1，第四级别的分光器为等比分光器，以70％*70％*70％＝34％的透射率过滤波长2，还同时过滤波长1。各个级别的不等比分光器的各个等比出光段202以及第四级别的等比分光器 均过滤波长1的光信号，并通过波长1的透射率来区分端口。各个分光器的级别通过波长2的透射率来区分。因此该ODN中仅包括两种类型的分光器，一是降低制造商的生产成本，二是便于施工人员安装，安装过程中不容易出错。如图18，各个级别的不等比分光器的各个等比出光段202以及第四级别的等比分光器均过滤波长1和波长2的光信号，并通过波长1的透射率和波长2的透射率来区分端口，各个分光器的级别通过波长3的透射率来区分。该ODN中同样仅包括两种类型的分光器，ODN中分光器类型越少，越有利于降低成本，安装过程中不容易出错。
在一实施例中，不等比出光段201与任一等比出光段202之间满足：不存在能够过滤相同波长的光滤波结构210。通过将不等比出光段201过滤的波长与等比出光段202过滤的波长区分开，因此不等比出光段201过滤的波长不会与等比出光段202过滤的波长相互影响，进而该ODN中可以设置更多级别的分光器，均可以实现识别ONU所在的光链路。
可以理解的是，各级不等比分光器的等比出光段202的具体实施方式可以参照上述有关各级等比分光器的介绍(例如图8至图14)，同样具有上述描述的效果，在此不再赘述。
在其他例子中，不等比出光段201上也可以设置至少两个光滤波结构210。
在一实施例中，如图7，以及图15-18所示，一级分光器31为不等比分光器，二级分光器41为等比分光器。具体实施方式可以参照上述相关描述，在此不再赘述。
可以理解的是，上述各个实施例中，一级分光器与二级分光器也可以存在可以过滤相同波长的光滤波结构210，只要使得各个光链路之间至少满足上述条件1和条件2之一即可。
本申请中的PON系统可以为下一代PON(next-generation PON，NG-PON)、NG-PON1、NG-PON2、千兆比特PON(gigabit-capable PON，GPON)、10吉比特每秒PON(10gigabit per second PON，XG-PON)、对称10吉比特无源光网络(10-gigabit-capable symmetric passive optical network，XGS-PON)、以太网PON(Ethernet PON，EPON)、10吉比特每秒EPON(10gigabit per second EPON，10G-EPON)、下一代EPON(next-generation EPON，NG-EPON)、波分复用(wavelength-division multiplexing，WDM)PON、时分波分堆叠复用(time-and wavelength-division multiplexing，TWDM)PON、点对点(point-to-point，P2P)WDM PON(P2P-WDM PON)、异步传输模式PON(asynchronous transfer mode PON，APON)、宽带PON(broadband PON，BPON)，等等，以及25吉比特每秒PON(25gigabit per second PON，25G-PON)、50吉比特每秒PON(50gigabit per second PON，50G-PON)、100吉比特每秒PON(100gigabit per second PON，100G-PON)、25吉比特每秒EPON(25gigabit per second EPON，25G-EPON)、50吉比特每秒EPON(50gigabit per second EPON，50G-EPON)、100吉比特每秒EPON(100gigabit per second EPON，100G-EPON)，以及ITU规定的其他各种PON系统、或者IEEE规定的其他各种PON系统等。
该PON系统可以包括OLT、ODN以及至少一个ONU(如图7-18所示)。在该PON系统中，从OLT到ONU的方向定义为下行方向，而从ONU到OLT的方向定义为上行方向。
OLT是光接入网的核心部件，通常位于中心局(Central Office，CO)，可以统一管理至少一个ONU，OLT用于为接入的各个ONU提供数据以及提供管理等等。OLT可以用于向各个ONU发送光信号，并接收各个ONU反馈的信息，以及对ONU反馈的信息或其他数据等进行处理。
ONU用于接收OLT发送的数据，响应OLT的管理命令、对用户的以太网数据进行缓存，并在OLT分配的发送窗口中向上行方向发送数据等等。
该ODN可以为上述实施例所述的ODN，在此不再赘述。可以理解的是，以下实施例同样具备上述ODN实施例中描述的有益效果。
以图14为例，ODN包括一级分光器11，该一级分光器包括8个端口，每一端口分别连接一个二级分光器，即一共有8个二级分光器。图14仅示出了两个二级分光器21和22，其中二级分光器21连接至一级分光器的端口1，二级分光器22连接至一级分光器的端口6，其余二级分光器未示出，其余二级分光器与二级分光器21和22可以为相同的分光器。每个二级分光器包括8个端口，每个端口可以连接一个ONU，其中，二级分光器21的端口4与第一ONU301连接，二级分光器22的端口7与第二ONU302连接，其余ONU未示出。该ODN一共包括64个光链路。为了便于描述，以下OLT与第一ONU301之间的光链路称为第一光链路，OLT与第二ONU302之间的光链路称为第二光链路。
可以理解的是，图14仅仅为一示例图，第一ONU301和第二ONU302所在的光链路并不仅仅局限于图14所示的光链路，以下各个实施例关于第一ONU301和第二ONU302的相关描述，可以适用于ODN中任一光链路上的ONU，也可以适用于其他ODN实施例中的ONU。
本申请实施例还提供一种识别PON系统中ONU所在光链路的方法。如图19所示，该方法包括：
步骤S10，OLT下行发送Q种波长的测试光，其中，Q为大于或等于1的整数，OLT与第一ONU301之间的第一光链路对至少一种波长的测试光具有特定的透射率。可以理解的是，光链路对测试光的特定的透射率可以参照上述实施例中光滤波结构210以特定的透射率过滤光信号的相关描述，在此不再赘述。
在一实施例中，Q至少等于第一光链路过滤的光信号的波长种类数。如图14所示，第一光链路所在的一级分光器的出光段200未设置光滤波结构210，第一光链路所在的二级分光器的出光段200能够过滤波长3和波长4的光信号，因此该第一光链路能够过滤的光信号的波长种类数为2种，即Q至少等于2，OLT至少下行发送波长3和波长4的测试光。
在另一实施例中，Q等于ODN中所有光链路过滤的光信号的波长种类数。如图14所示，ODN能够过滤波长1，波长2，波长3和波长4的光信号，因此OLT可以下行发送波长1，波长2，波长3和波长4的测试光。即Q等于4。以下实施例以Q＝4为例描述。
在一实施例中，第一光链路上设有至少一个光过滤结构，一个光过滤结构以特定的透射率过滤一种波长的测试光。如图14中的ONU1所在的第一光链路，以透射率0％过滤波长3，以及以透射率0％过滤波长4。
可以理解的是，还存在一种特殊情况，即当一条光链路上未设置光滤波结构210时，第一光链路对测试光具有特定的透射率可以理解为第一光链路对每一种波长的测试光的透射率均为100％。一般情况下，每个ODN中最多存在一个这样的光链路。
在一实施例中，Q大于或等于2，步骤S10包括：OLT按时序依次下行发送Q种波长的测试光。
步骤S20，第一ONU301接收OLT发送的Q种波长的测试光。在一实施例中，Q大于或等于2，步骤S20包括：ONU按照时序依次接收OLT发送的Q种波长的测试光。
步骤S30，第一ONU301确定接收的每一种波长的测试光的接收功率值。
步骤S40，第一ONU301生成反馈信息，该反馈信息用于指示测试光的接收功率值。
步骤S50，第一ONU301向OLT发送反馈信息。
在一实施例中，反馈信息可以为多条，一条反馈信息指示一种波长的测试光的接收功率值。在另一实施例中，反馈信息可以为一条，一条反馈信息指示Q种波长的测试光的接收功 率值。或者在另一实施例中，反馈信息可以为多条，一条反馈信息指示至少2种(小于Q种)波长的测试光的接收功率值。
步骤S60，OLT接收第一ONU301反馈的反馈信息。
步骤S70，OLT根据至少一种波长的测试光的接收功率值确定透射率。包括以下几种方式：
方式一：OLT接收到的测试光的接收功率值，除了包括在第一光链路上具有特定透射率的测试光的接收功率值，还包括在第一光链路上具有全透射率的测试光的接收功率值，该方法还包括：OLT将接收到的多个接收功率值中的最大值确定为基准接收功率值P0，步骤S70包括：OLT根据至少一种波长的测试光的接收功率值与基准接收功率值，确定至少一种波长的测试光在第一光链路的透射率。
OLT可以将小于P0的接收功率值P1作为在第一光链路上具有特定透射率的测试光的接收功率值。透射率例如可以等于10^(P1/10)/10^(P0/10)。例如，对于图14所示的第二ONU302所在的第一光链路，波长3透射率50％，波长4透射率50％。
方式二：该方法还包括：OLT下行发送业务光信号；ONU接收该业务光信号，ONU确定业务光信号的业务光接收功率值，并且ONU向OLT发送业务光信息，业务光信息用于指示业务光信号的业务光接收功率值。
OLT接收第一ONU301反馈的业务光信息；OLT根据至少一种波长的测试光的接收功率值与业务光接收功率值，确定至少一种波长的测试光在第一光链路的透射率。
该方式中的业务光接收功率值在第一光链路上具有全透射率，类似于方式一中的P0，透射率的计算公式同方式一，在此不再赘述。
步骤S80，OLT根据光链路与波长、透射率之间的关系，以及所述至少一种波长和确定的透射率，确定第一ONU301位于第一光链路。
在一实施例中，OLT内部保存有各个光链路与波长、透射率之间的关系。在一实施例中，光链路可以通过光链路编号来表征，例如图14中包括64条光链路，则一共有64个光链路编号。在另一实施例中，光链路还可以通过分光器级别和分光器端口号来表征，例如，对于图14所示的第一ONU301所在的第一光链路可以表征为：一级分光器端口1和二级分光器端口4。第一光链路与波长和透射率之间的关系可以为：一级分光器端口1和二级分光器端口4，波长3透射率0％，波长4透射率0％。
在执行上述步骤S80时，OLT还要知道接收功率值具体是哪种波长的测试光的接收功率值。该方法还包括，OLT确定接收功率值对应的测试光的波长。包括以下几种方式：
方式一：OLT每次下行发送一种波长的测试光之后，等待接收第一ONU301反馈的反馈信息；
ONU每次接收到一种波长的测试光之后，确定该测试光的接收功率值以及生成反馈信息，并向OLT发送反馈信息，该反馈信息指示该测试光的接收功率值。
OLT在接收到反馈信息之后，再下行发送下一种波长的测试光。ONU接收下一种波长的测试光，并且ONU再重复上述生成以及发送反馈信息的步骤。因此，OLT接收到反馈信息的时刻之前发送的测试光的波长即为该反馈信息指示的接收功率值对应的测试光的波长。该实施例不需要占用额外的信息来指示波长，直接根据时序即可判断波长。不需要额外改动信息格式。
方式二：OLT按时序依次下行发送Q种波长的测试光之后，ONU按时序依次接收Q种波长的测试光，并分别确定Q种波长的接收功率值，ONU记录Q种波长的测试光的接收时 序。
在一实施例中，ONU可以向OLT发送Q条反馈信息，每一条反馈信息指示一种波长的接收功率值。ONU按照各种波长的测试光的接收时序依次发送对应的Q条反馈信息。OLT根据接收的反馈信息的时序即可确定对应的测试光的波长。
在另一实施例中，ONU可以向OLT发送一条反馈信息，该反馈信息指示Q种波长的接收功率值以及Q种波长的测试光的接收时序。
方式三：OLT下行发送的Q种波长的测试光中的每一种测试光中均携带标签，其中，任意两种波长的测试光携带的标签不同；反馈信息用于指示所述测试光的接收功率值以及与该接收功率值对应的测试光中携带的标签；该方法还包括：OLT根据标签确定接收功率值对应的测试光的波长。该方式中，OLT发送测试光以及ONU发送反馈信息不受时序限制，实现起来比较灵活。
进一步的，该方法还可以包括：OLT发送光链路信息，光链路信息用于指示第一光链路。OLT可以向其他服务器发送光链路信息。光链路信息具体用于指示位于第一光链路上的各级分光器以及分光器的端口。例如，光链路信息包括各级分光器中每个分光器的标识信息，以及位于第一光链路上的每一端口的标识信息。
上述实施例中，ONU向OLT反馈接收功率值，由OLT根据接收功率值确定透射率，并进一步确定光链路信息。可以理解的是，在另一实施例中，也可以由ONU根据接收功率值确定透射率，并向OLT反馈透射率(如反馈信息用于指示透射率)，并由OLT确定光链路信息，其他细节可参考上述实施例，在此不再赘述。或者，在另一实施例中，也可以由ONU根据接收功率值确定透射率，并进一步确定光链路信息，然后ONU将光链路信息反馈给OLT(如反馈信息用于指示光链路信息)，其他细节可参考上述实施例，在此不再赘述。
本发明还提供一种如上述各个实施例所述的OLT 400。如图20所示，OLT400包括处理器410和收发器420。
该收发器420包括光发射器和光接收器。光发射器将电信号转换为光信号，并将光信号发送到ODN，光接收器从ODN网络接收光信号，并将光信号转换为电信号。光发射器可以通过发光器件，例如气体激光器、固体激光器、液体激光器、半导体激光器、直调激光器等实现。光接收器可以通过光检测器，例如光电检波器或者光电二极管(如雪崩二极管)等实现。
该收发器420可以为光模块。该光模块还可以包括控制电路。上述光发射器具有波长可调功能，可以为分布布拉格反射(Distributed Bragg Reflector，DBR)激光器，也可以是一组分布反馈布拉格(Distributed Feedback Bragg,DFB)激光器拼接构成，也可以是其他形式构成。该光模块可以包括一个光发射器，该光发射器可同时发送业务波长和测试波长。
或者，该光模块也可以包括两个光发射器，一个光发射器用于发送业务光，另一个光发射器用于发送测试光。
处理器410用于实现ONU的管理、DBA(Dynamic Bandwidth Allocation，动态带宽分配)、ONU注册、数据收发等功能。处理器410可以通过硬件电路实现，也可以通过软件程序实现，也可以通过硬件和软件结合的方式实现，比如现场可编程门阵列(Field-Programmable Gate Array，FPGA)，或者专用集成芯片(Application Specific Integrated Circuit，ASIC)或者系统芯片(System on Chip，SoC)，或者媒体接入控制(Media access control,MAC)、或者中央处理器(Central Processor Unit，CPU)，或者网络处理器(Network Processor，NP)，或者数字信 号处理电路(Digital Signal Processor，DSP)，或者微控制器(Micro Controller Unit，MCU)，或者可编程控制器(Programmable Logic Device，PLD)或其他集成芯片。处理器410例如可以执行上述确定透射率、确定基准接收功率值P0、确定光链路等。
OLT400还包括存储器430，可以是只读存储器(Read Only Memory，ROM)，静态存储设备，动态存储设备或者随机存取存储器(Random Access Memory，RAM)，也可以是寄存器，也可以为非易失性存储器(non-volatile memory)，例如闪存flash，或至少一个磁盘存储器。在通过软件或者固件来实现本发明实施例提供的技术方案时，用于实现本发明实施例提供的技术方案的程序代码保存在存储器430中，并由处理器410来执行。
其中，存储器430、处理器410可以分别位于不同的物理实体上，也可以部分或全部集成在一个物理实体上，该物理实体可以是现场可编程门阵列(Field-Programmable Gate Array，FPGA)，或者专用集成芯片(Application Specific Integrated Circuit，ASIC)或者系统芯片(System on Chip，SoC)，或者中央处理器(Central Processor Unit，CPU)，或者网络处理器(Network Processor，NP)，或者数字信号处理电路(Digital Signal Processor，DSP)，或者微控制器(Micro Controller Unit，MCU)，或者可编程控制器(Programmable Logic Device，PLD)或其他集成芯片。
OLT400还包括波分复用(wavelength division multiplexing，WDM)器440。波分复用器与收发器420相连，当OLT400发送光信号时，波分复用器充当复用器。当OLT400接收光信号时，波分复用器充当解复用器。波分复用器也可以称为光耦合器。
可以理解的是，波分复用器440也可以独立于OLT400存在。
根据上述实施例，图20所示的OLT400执行的是图19所示实施例中的步骤S10、S60、S70、S80。具体的，处理器410执行步骤S70、S80。收发器420执行步骤S10、S60。处理器410和收发器420执行上述步骤时的更多细节可以上述方法各个实施例及附图的相关描述，此处不再赘述。同样的，OLT400具备与上述方法实施例中相应的有益效果，在此不再赘述。
可以理解的是，上述描述的OLT400还可以包括其他器件，在此不再赘述。
本发明还提供一种如上述各个实施例所述的ONU300。如图21所示，ONU300包括处理器310和收发器320。
该收发器320包括光发射器和光接收器。光发射器将电信号转换为光信号，并将光信号发送到ODN，光接收器从ODN网络接收光信号，并将光信号转换为电信号。光发射器可以通过发光器件，例如气体激光器、固体激光器、液体激光器、半导体激光器、直调激光器等实现。光接收器可以通过光检测器，例如光电检波器或者光电二极管(如雪崩二极管)等实现。
该收发器320可以为光模块。该光模块包括光组件和控制电路。或者，该收发器320也可以为光组件。
光组件包括光发射器和光接收器。该光组件可以包括一个光发射器和一个光接收器，该光接收器用于接收业务光和测试光。或者该光组件也可以包括一个光发射器和两个光接收器，其中一个光接收器用于接收业务光，另一个光接收器用于接收测试光。
处理器310用于实现ONU300的管理、DBA(Dynamic Bandwidth Allocation，动态带宽分配)、ONU300注册、数据收发等功能。处理器310可以通过硬件电路实现，也可以通过软件程序实现，也可以通过硬件和软件结合的方式实现，比如现场可编程门阵列(Field-Programmable Gate Array，FPGA)，或者专用集成芯片(Application Specific Integrated  Circuit，ASIC)或者系统芯片(System on Chip，SoC)，或者媒体接入控制(Media access control,MAC)、或者中央处理器(Central Processor Unit，CPU)，或者网络处理器(Network Processor，NP)，或者数字信号处理电路(Digital Signal Processor，DSP)，或者微控制器(Micro Controller Unit，MCU)，或者可编程控制器(Programmable Logic Device，PLD)或其他集成芯片。处理器310例如可以执行上述确定测试光和业务光的接收功率值、生成反馈信息和业务光信息等。
ONU300还可以包括存储器330，可以是只读存储器(Read Only Memory，ROM)，静态存储设备，动态存储设备或者随机存取存储器(Random Access Memory，RAM)，也可以是寄存器，也可以为非易失性存储器(non-volatile memory)，例如闪存flash，或至少一个磁盘存储器。在通过软件或者固件来实现本发明实施例提供的技术方案时，用于实现本发明实施例提供的技术方案的程序代码保存在存储器330中，并由处理器310来执行。
其中，存储器330、处理器310可以分别位于不同的物理实体上，也可以部分或全部集成在一个物理实体上，该物理实体可以是现场可编程门阵列(Field-Programmable Gate Array，FPGA)，或者专用集成芯片(Application Specific Integrated Circuit，ASIC)或者系统芯片(System on Chip，SoC)，或者中央处理器(Central Processor Unit，CPU)，或者网络处理器(Network Processor，NP)，或者数字信号处理电路(Digital Signal Processor，DSP)，或者微控制器(Micro Controller Unit，MCU)，或者可编程控制器(Programmable Logic Device，PLD)或其他集成芯片。
ONU300还包括波分复用(wavelength division multiplexing，WDM)器340。波分复用器340与收发器320相连。
根据上述实施例，图21所示的ONU300执行的是图19所示实施例中的步骤S20、S30、S40、S50。具体的，处理器310执行步骤S30、S40。收发器320执行步骤S20、S50。处理器310和收发器320执行上述步骤时的更多细节可以上述方法各个实施例及附图的相关描述，此处不再赘述。同样的，ONU300具备与上述方法实施例中相应的有益效果，在此不再赘述。
可以理解的是，上述描述的ONU300还可以包括其他器件，在此不再赘述。
本发明还提供一种PON系统，该PON系统包括上述实施例描述的OLT400、ONU300和ODN。具体可以参照上述实施例，在此不再赘述。同样的，该PON系统具备与上述各个实施例中相应的有益效果，在此不再赘述。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本发明实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘Solid State Disk (SSD))等。
综上所述，以上仅为本发明的实施例而已，并非用于限定本发明的保护范围。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (35)

  1. 一种分光器，其特征在于，所述分光器包括入光段和N个出光段，N为大于或等于2的整数；
    至少N-1个所述出光段中的每个所述出光段上设有至少一个光滤波结构，每一所述光滤波结构以特定的透射率过滤一种波长的光信号；
    设有所述光滤波结构的任意两个所述出光段满足以下条件1和条件2中的至少一个：条件1：过滤的至少一种所述波长不同；条件2：对至少一种所述波长的光信号的透射率不同；
    其中，设有所述光滤波结构的出光段中，存在至少两个所述出光段满足所述条件2。
  2. 如权利要求1所述的分光器，其特征在于，所述N个出光段中，存在一个未设置所述光滤波结构的出光段，还存在至少一个设置一个所述光滤波结构的出光段。
  3. 如权利要求1或2所述的分光器，其特征在于，所述N个出光段中，至少一个所述出光段上设有M个所述光滤波结构，每一个所述出光段过滤M种波长的光信号，M为大于或等于2的整数。
  4. 如权利要求1至3任一项所述的分光器，其特征在于，所述分光器为等比分光器或不等比分光器。
  5. 如权利要求4所述的分光器，其特征在于，所述不等比分光器的N个所述出光段包括1个不等比出光段和N-1个等比出光段，所述不等比出光段上设置一个所述光滤波结构。
  6. 如权利要求5所述的分光器，其特征在于，所述不等比出光段与任一所述等比出光段之间满足：不存在能够过滤相同波长的所述光滤波结构。
  7. 如权利要求1至6任一项所述的分光器，其特征在于，所述分光器为平面光波导PLC分光器，所述PLC分光器包括入光端光纤、N根出光端光纤、和平面光波导；
    所述平面光波导包括入光波导端、N个出光波导端、以及连接于所述入光波导端和所述N个出光波导端之间的中间分支波导；
    所述入光端光纤与所述入光波导端连接，所述入光段包括所述入光端光纤与所述入光波导端；
    所述N根出光端光纤与所述N个出光波导端一一对应连接；
    每一所述出光段包括所述中间分支波导、一对相互连接的所述出光波导端和所述出光端光纤。
  8. 如权利要求7所述的分光器，其特征在于，所述光滤波结构设置在所述中间分支波导、所述出光波导端、和所述出光端光纤中的至少一种。
  9. 如权利要求8所述的分光器，其特征在于，所述出光端光纤包括带纤，所述光滤波结构设置在所述带纤上；
    所述分光器还包括固定盒体，所述固定盒体用于将所述带纤上设有所述光滤波结构的部分封装固定在所述固定盒体内部。
  10. 如权利要求1至6任一项所述的分光器，其特征在于，所述分光器为熔融拉锥分光器，所述熔融拉锥分光器包括入光端光纤、耦合区光纤和N根出光端光纤，所述光 滤波结构设置在所述出光端光纤上。
  11. 如权利要求1至10任一项所述的分光器，其特征在于，所述光滤波结构为一段光栅，或者所述光滤波结构为滤光膜。
  12. 一种光分配网络ODN，其特征在于，包括一级分光器和二级分光器；
    所述一级分光器为权利要求1至11任一项所述的分光器，且所述一级分光器的入光段称为第一入光段，所述一级分光器的出光段称为第一出光段；
    所述二级分光器为权利要求1至11任一项所述的分光器，且所述二级分光器的入光段称为第二入光段，所述二级分光器的出光段称为第二出光段；
    一所述第一出光段与一所述第二入光段连接；
    所述第一入光段、一对相互连接的所述第一出光段和所述第二入光段、以及一所述第二出光段形成一条光链路；
    任意两条所述光链路满足以下条件1和条件2中的至少一个：条件1：过滤的至少一种所述波长不同；条件2：对至少一种所述波长的光信号的透射率不同；
    其中，存在至少两条所述光链路满足所述条件2。
  13. 如权利要求12所述的ODN，其特征在于，所述一级分光器和所述二级分光器均为等比分光器，所述二级分光器为多个，且各个所述二级分光器为相同的分光器，任一一级分光器与任一二级分光器为不同的分光器。
  14. 如权利要求13所述的ODN，其特征在于，任一所述第一出光段和任一所述第二出光段满足：不存在能够过滤相同波长的所述光滤波结构。
  15. 如权利要求12所述的ODN，其特征在于，所述一级分光器与所述二级分光器均为不等比分光器；
    所述不等比分光器的出光段包括1个不等比出光段和N-1个等比出光段；
    所述一级分光器的所述不等比出光段与所述二级分光器的所述入光段连接。
  16. 如权利要求15所述的ODN，其特征在于，所述一级分光器与所述二级分光器为相同的不等比分光器；且所述不等比分光器的不等比出光段与任一等比出光段满足：不存在能够过滤相同波长的所述光滤波结构。
  17. 一种识别无源光网络PON系统中光网络单元ONU所在光链路的方法，其特征在于，包括：
    OLT下行发送Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与第一ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；
    所述OLT接收所述第一ONU反馈的反馈信息，所述反馈信息用于指示所述测试光的接收功率值；
    所述OLT根据至少一种波长的测试光的接收功率值确定透射率；
    所述OLT根据光链路与波长、透射率之间的关系，以及所述至少一种波长和确定的所述透射率，确定所述第一ONU位于所述第一光链路。
  18. 如权利要求17所述的方法，其特征在于，Q大于或等于2，所述OLT下行发送Q种波长的测试光包括：所述OLT按时序依次下行发送所述Q种波长的测试光；
    其中，所述OLT每次下行发送一种波长的所述测试光之后，等待接收所述第一ONU 反馈的所述反馈信息；所述OLT在接收到所述反馈信息之后，再下行发送下一种波长的所述测试光。
  19. 如权利要求17所述的方法，其特征在于，所述OLT下行发送的所述Q种波长的测试光中的每一种测试光中均携带标签，其中，任意两种波长的测试光携带的所述标签不同；
    所述反馈信息用于指示所述测试光的接收功率值以及该测试光中携带的所述标签；
    所述方法还包括：所述OLT根据所述标签确定所述接收功率值对应的所述测试光的波长。
  20. 如权利要求17至19任一项所述的方法，其特征在于，所述方法还包括：
    所述OLT下行发送业务光信号；
    所述OLT接收所述第一ONU反馈的业务光信息，所述业务光信息用于指示所述业务光信号的业务光接收功率值；
    所述OLT根据所述至少一种波长的测试光的接收功率值与所述业务光接收功率值，确定所述至少一种波长的测试光在所述第一光链路的透射率。
  21. 如权利要求17至20任一项所述的方法，其特征在于，所述方法还包括：
    所述OLT发送光链路信息，所述光链路信息用于指示所述第一光链路。
  22. 如权利要求21所述的方法，其特征在于，所述光链路信息包括所述各级分光器中每个所述分光器的标识信息，以及位于所述第一光链路上的每一所述端口的标识信息。
  23. 如权利要求17至22任一项所述的方法，其特征在于，所述PON系统包括光分配网络ODN，所述ODN为如权利要求12至16任一项所述的ODN。
  24. 一种识别无源光网络PON系统中光网络单元ONU所在光链路的方法，其特征在于，包括：
    光网络单元ONU接收光线路终端OLT发送的Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与所述ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；
    所述ONU确定接收的每一种波长的所述测试光的接收功率值；
    所述ONU向所述OLT发送反馈信息，所述反馈信息用于指示所述测试光的接收功率值。
  25. 如权利要求24所述的方法，其特征在于，Q大于或等于2，所述ONU接收OLT发送的Q种波长的测试光包括：所述ONU按照时序依次接收OLT发送的Q种波长的测试光；
    其中，所述ONU接收到一种波长的所述测试光之后，向所述OLT发送反馈信息，所述反馈信息用于指示所述一种波长的所述测试光的接收功率值；并在发送所述反馈信息之后，所述ONU接收下一种波长的所述测试光。
  26. 如权利要求24所述的方法，其特征在于，所述ONU接收的所述Q种波长的测试光中的每一种测试光中均携带标签，其中，任意两种波长的测试光携带的所述标签不同；所述ONU向所述OLT发送确定的每一种波长的所述测试光的接收功率值包括：
    所述ONU向所述OLT发送反馈信息，所述反馈信息用于指示所述测试光的接收功率值以及指示该测试光中携带的所述标签。
  27. 如权利要求24至26任一项所述的方法，其特征在于，所述方法还包括：
    所述ONU接收所述OLT发送的业务光信号；
    所述ONU确定所述业务光信号的业务光接收功率值；
    所述ONU向所述OLT发送业务光信息，所述业务光信息用于指示所述业务光信号的业务光接收功率值。
  28. 如权利要求24至27任一项所述的方法，其特征在于，所述PON系统包括光分配网络ODN，所述ODN为如权利要求12至16任一项所述的ODN。
  29. 一种光线路终端OLT，其特征在于，所述OLT包括收发器和处理器；
    所述收发器用于下行发送Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与第一ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；
    所述收发器还用于接收所述第一ONU反馈的反馈信息，所述反馈信息用于指示所述测试光的接收功率值；
    所述处理器用于根据至少一种波长的测试光的接收功率值确定透射率；
    所述处理器还用于根据光链路与波长、透射率之间的关系，以及所述至少一种波长和确定的所述透射率，确定所述第一ONU位于所述第一光链路。
  30. 如权利要求29所述的OLT，其特征在于，Q大于或等于2，所述收发器按时序依次下行发送所述Q种波长的测试光；
    其中，所述收发器每次下行发送一种波长的所述测试光之后，等待接收所述第一ONU反馈的所述反馈信息；所述收发器在接收到所述反馈信息之后，再下行发送下一种波长的所述测试光。
  31. 如权利要求29或30所述的OLT，其特征在于，所述收发器还用于发送光链路信息，所述光链路信息用于指示所述第一光链路，所述光链路信息包括所述各级分光器中每个所述分光器的标识信息，以及位于所述第一光链路上的每一所述端口的标识信息。
  32. 一种光网络单元ONU，其特征在于，所述ONU包括收发器和处理器；
    所述收发器用于接收光线路终端OLT发送的Q种波长的测试光，其中，Q为大于或等于1的整数，所述OLT与所述ONU之间的第一光链路对至少一种波长的所述测试光具有特定的透射率；
    所述处理器用于确定接收的每一种波长的所述测试光的接收功率值；
    所述收发器还用于向所述OLT发送反馈信息，所述反馈信息用于指示所述测试光的接收功率值。
  33. 如权利要求32所述的ONU，其特征在于，Q大于或等于2，所述收发器按照时序依次接收OLT发送的Q种波长的测试光；
    其中，所述收发器接收到一种波长的所述测试光之后，向所述OLT发送反馈信息，所述反馈信息用于指示所述一种波长的所述测试光的接收功率值；并在发送所述反馈信息之后，所述收发器接收下一种波长的所述测试光。
  34. 如权利要求32或33所述的ONU，其特征在于，
    所述收发器还用于接收所述OLT发送的业务光信号；
    所述处理器还用于确定所述业务光信号的业务光接收功率值；
    所述收发器还用于向所述OLT发送业务光信息，所述业务光信息用于指示所述业务光信号的业务光接收功率值。
  35. 一种无源光网络PON系统，其特征在于，所述PON系统包括如权利要求29至31任一项所述的光线路终端OLT，如权利要求32至34任一项所述的光网络单元ONU，以及如权利要求12至16任一项所述的光分配网络ODN。
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