WO2009056064A1 - An optical line terminal, a remote node unit, an optical transimission method and system thereof - Google Patents

An optical line terminal, a remote node unit, an optical transimission method and system thereof Download PDF

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Publication number
WO2009056064A1
WO2009056064A1 PCT/CN2008/072823 CN2008072823W WO2009056064A1 WO 2009056064 A1 WO2009056064 A1 WO 2009056064A1 CN 2008072823 W CN2008072823 W CN 2008072823W WO 2009056064 A1 WO2009056064 A1 WO 2009056064A1
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Prior art keywords
optical
group
optical signals
signals
carrier
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English (en)
French (fr)
Inventor
Fan Yu
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Priority to EP08844454.2A priority Critical patent/EP2209228B1/en
Publication of WO2009056064A1 publication Critical patent/WO2009056064A1/zh
Priority to US12/766,533 priority patent/US8625990B2/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0278—WDM optical network architectures
    • H04J14/0282—WDM tree architectures

Definitions

  • the invention belongs to the technical field of network communication, and relates to an optical line terminal, a remote node unit, an optical transmission method and a system, in particular to an optical line terminal and a remote node capable of reducing the number of optical network light sources in a wavelength division multiplexing system. Unit, optical transmission method and system. Background technique
  • optical line terminals (0LT) and optical network units (0NU) are allocated optical signals through optical splitters, and the uplink and downlink carriers are respectively used differently.
  • the wavelength is used for data transmission.
  • the existing optical network system has a large optical attenuation, and the traditional Passive Optical Network (PON) technology is limited in terms of transmission and separation, and each 0NU is obtained.
  • PON Passive Optical Network
  • the upstream bandwidth is limited, and it is difficult to meet the needs of high-bandwidth services such as high-definition digital.
  • each ONU is allocated two different wavelengths for transmission of uplink and downlink carriers, respectively.
  • the optical line terminal is placed in the central office (C0) as shown in Figure 1.
  • the optical line terminal (0LT) uses a multi-wavelength source, and the downlink is transmitted to 0 and 1, 0NU2. . . ONUn is modulated to a wavelength of ⁇ . 1.
  • ⁇ 2, . . . ⁇ is transmitted on the optical carrier, and the signal is allocated to the destination optical network unit through a passive remote node (RN) to complete the downlink transmission.
  • RN passive remote node
  • Wavelength-Division Multiplexing Access A is used to solve the channel competition problem.
  • Each volume uses a specific wavelength to carry uplink data.
  • n zero volumes are respectively in ⁇ ⁇ . ⁇ 2 . . . ⁇ ′ carries the uplink data on the optical carrier, and does not require timing and network synchronization.
  • the uplink signal is uploaded to the receiving end of the OLT through a Wavelength Grating Router (WGR), and is uploaded to the receiving end of the OLT through the Arrayed Waveguide Grating (AWG) in FIG.
  • WGR Wavelength Grating Router
  • AWG Arrayed Waveguide Grating
  • the existing TOM-P0N has too much initial investment and high cost.
  • each volume uses different wavelengths as the upstream and downstream carrier signals, and the TOM-P0N system will use 2N light sources; for some wavelength division multiplexing systems, Each 0 requires two uplink carriers to obtain higher uplink modulated signal power.
  • N zero-volume systems each of which occupies 3 optical carriers, uses one wavelength of downlink carrier, and two different wavelengths.
  • 3N sources will be used in the system.
  • the prior art mainly adopts the following two methods:
  • each 0NU uses the same wavelength to transmit the uplink and downlink signals, and N light sources will be used in the system.
  • the total number of light sources can be reduced by half compared with the system shown in Figure 1.
  • 0 The downlink optical signal carrying the downlink data from the 0LT is divided into two parts, one part is used for detecting and recovering downlink data, and the other part is used for uplink data transmission, and the uplink data is re-modulated on the part of the downlink light, and then Send back to 0LT.
  • the uplink and downlink of each ONU are carried at the same wavelength, 0 without setting the light source, and only setting the light source at 0LT.
  • the optical network unit uses the remodulation method, and the downlink data carried on the downlink optical has an influence on the modulation of the uplink data, which affects the reception quality of the uplink data at the system 0LT.
  • Two high-power wide-spectrum light sources are set at 0LT, and the wide-spectrum light source spectrum division method is used to provide the downlink optical carrier and the upstream optical carrier for 0LT and 0, respectively, such as the broad-spectrum light source in Figure 3 (Broadband) L ght Source (abbreviated as BLS), the second wide-spectrum light source is used to provide a locked-wavelength light source to the OLT, and the first wide-spectrum light source is used to provide a lock-wavelength light source for zero.
  • BLS Broadband L ght Source
  • a wide-spectrum light from a broad-spectrum light source is demultiplexed by a demulse-demultiplexer (DEMUX) to obtain a series of narrow-spectrum light, which is injected into a series of receiving/transmitting parts of 0LT or 0 in the central office.
  • An injection locking light source is generated, as shown in FIG.
  • the above-mentioned spectral division method divides the broadband spectrum into a plurality of narrow spectra, and there is a spectral gap between the narrow spectra. Therefore, the utilization of the light source power is not high; at the same time, the high-power wide-spectrum light source device is not mature and high in cost.
  • the wavelength division multiplexing system needs to use more light sources. Although there are ways to reduce the number of light sources in the prior art, problems such as low signal transmission quality, low power utilization of the light source, or high cost are also brought. . Summary of the invention
  • a first object of the present invention is to provide an optical transmission method for solving the problem that the existing optical network system has a large number of light sources, high cost, and existing technical solutions for reducing the number of network light sources, and the signal transmission quality is not high, and the power source power is utilized.
  • the problem is not high, and the number of light sources in the network is reduced, the reception quality is improved, and the cost of the system is reduced.
  • a second object of the present invention is to provide an optical line terminal for solving the problem that the existing optical line terminal reduces the number of network light sources, and needs to add a high-power wide-spectrum light source device, and the power utilization rate of the light source is not high, and the cost is high or
  • the existing technical solutions have problems such as low reception quality, and the like, thereby reducing the number of light sources in the network, improving the signal transmission quality, and simultaneously reducing the cost of the system.
  • a third object of the present invention is to provide a remote node unit for solving the problems of a large number of optical sources and high cost of the existing optical network system, thereby reducing the number of light sources in the network and improving signal transmission quality. Reduce the cost of the system.
  • a fourth object of the present invention is to provide an optical transmission system for solving the problem that the existing optical network system has a large number of light sources, high cost, and the existing system for reducing the number of network light sources is not high, and the light is not high.
  • the problem of low source power utilization such as reducing the number of light sources in the network, improving the signal transmission quality, and reducing the cost of the system.
  • Part or all of the M different wavelength optical signals generated by the M light sources are respectively branched by power to form a first group of optical signals including the first branched optical signals and a second set of optical signals including the second branched optical signals, wherein The first group of optical signals and the second group of optical signals each having N different wavelengths;
  • the first group of optical signals and the second group of optical signals are cross-routed to form N carrier group signals that need to be provided to N optical network units, where the N carrier group signals share K carriers.
  • Each carrier group signal includes a carrier of a first group of optical signals and a carrier of a second group of optical signals, and each carrier group signal includes a carrier having a different wavelength.
  • a processing module configured to perform power branching on a part or all of a group of optical signals having different wavelengths generated by the light source module, to form a first group of optical signals including the first branched optical signal and a second optical signal including the second branched optical signal Generating an optical signal, and modulating the downlink data to the first group of optical signals, wherein the first group of optical signals and the second group of optical signals each have N different wavelengths, and the second group of optical signals are used As an uplink carrier;
  • a wavelength division multiplexing module configured to separately perform wavelength division multiplexing on the optical signal modulated with downlink data and the second optical signal, respectively, to form a first group of optical signals respectively modulated with downlink data and used as an uplink carrier Two channels of mixed optical signals of the second set of optical signals;
  • an embodiment of a remote node unit of the present invention includes: a cross-routing module, configured to cross-route the input multi-channel mixed optical signals to form a plurality of carrier group signals composed of different wavelengths, Multiple carrier group signals are respectively used as carriers of different optical network units;
  • Each of the mixed optical signals of the multiple mixed optical signals includes a plurality of carriers of different wavelengths, and the multiplexed optical signals have one or more carriers of the same wavelength.
  • An optical line terminal configured to generate a set of light sources of M different wavelengths, and respectively perform power branching on some or all of the light sources to generate a first group of optical signals including the first branch optical signal and a second group including the second branched optical signal
  • the optical signal is modulated in the first group of optical signals, and the first group of optical signals modulated with the downlink data and the second group of optical signals are separately wavelength-multiplexed to form downlink data respectively modulated a two-way mixed optical signal of the first set of optical signals and the second set of optical signals;
  • each carrier group signal comprises one carrier of the mixed optical signal of the unmixed downlink data of the two mixed optical signals and one carrier of the mixed optical signal of the two mixed optical signals modulated with the downlink data.
  • the present invention provides an optical line terminal, a remote node unit, and an optical transmission method and system capable of reducing the number of network light sources.
  • Each technical solution reuses a generated light source to generate an optical signal generated by one or a group of light sources. Divided into two groups of the same two or overlapping wavelengths, branching the power of one mixed optical signal into the same two paths, and treating two or two sets of optical signals as respectively Carrier of the same optical network unit.
  • the carriers of the same wavelength generated by the same light source are respectively used for carriers of different optical network units (0) through subsequent cross-routes.
  • a system with N 0s needs to use 2N or 3N light sources.
  • Wavelength division multiplexing can use an existing arrayed waveguide grating (Arrowed Wavegui de Grating, AWG for short), and the modulation can be applied.
  • a mature Mach-Zehnder Modul a tor (abbreviated as ⁇ ) or an electroabsorption modulator (EAM), etc., and the wavelength of the phase wave of the prior art scheme 2 is not The same, so the quality of the signal transmission is greatly improved compared with the prior art solution 1.
  • 1 is a schematic structural diagram of a conventional wavelength division multiplexing system
  • FIG. 2 is a schematic structural diagram of a conventional passive modulation optical network system based on remodulation
  • FIG. 3 is a schematic structural diagram of a conventional passive optical network system based on broad spectrum source spectrum division
  • FIG. 4 is a flow chart of a first embodiment of an optical transmission method capable of reducing the number of light sources according to the present invention
  • FIG. 5 is a flow chart of a second embodiment of an optical transmission method capable of reducing the number of light sources according to the present invention
  • FIG. 7 is a flowchart of Embodiment 4 of an optical transmission method capable of reducing the number of light sources according to the present invention
  • FIG. 8 is a flowchart of Embodiment 5 of an optical transmission method capable of reducing the number of light sources according to the present invention
  • FIG. 10 is a schematic structural diagram of Embodiment 1 of an optical line terminal according to the present invention
  • FIG. 11 is a schematic structural view of Embodiment 2 of an optical line terminal according to the present invention
  • 12 is a schematic structural diagram of Embodiment 1 and a remote node unit of an optical transmission system capable of reducing the number of light sources according to the present invention
  • FIG. 13 is a schematic structural diagram of Embodiment 2 of the optical transmission system capable of reducing the number of light sources, Embodiment 2 of the remote node unit, and Embodiment 3 of the optical line terminal according to the present invention;
  • FIG. 14 is a schematic structural diagram of Embodiment 3 of an optical transmission system capable of reducing the number of light sources according to the present invention
  • FIG. 15 is a schematic structural diagram of Embodiment 4 of the optical transmission system capable of reducing the number of light sources according to the present invention
  • Embodiment 5 is a schematic structural diagram of Embodiment 5 of an optical transmission system capable of reducing the number of light sources according to the present invention
  • FIG. 17 is a schematic structural diagram of Embodiment 6 of an optical transmission system capable of reducing the number of light sources according to the present invention
  • FIG. 18 is a schematic structural diagram of Embodiment 7 of the optical transmission system capable of reducing the number of light sources according to the present invention
  • FIG. 19 is a schematic structural diagram of Embodiment 8 of the optical transmission system capable of reducing the number of light sources according to the present invention.
  • FIG. 20 is a schematic structural diagram of Embodiment 9 of the optical transmission system capable of reducing the number of light sources according to the present invention and a seventh embodiment of the remote node unit. detailed description
  • FIG. 4 is a flow chart of Embodiment 1 of an optical transmission method capable of reducing the number of light sources according to the present invention. As shown in FIG. 4, this embodiment includes:
  • Step 1 The optical signal generated by one light source is branched into two optical signals.
  • Step 20 The two optical signals of the same wavelength are respectively used as carriers of different optical network units.
  • the optical signal power emitted by the same light source can be branched into two optical signals of the same wavelength, respectively, as the uplink carrier and the downlink carrier of different optical network units, for example, using one power source power branch of the wavelength input to generate two wavelengths.
  • a t optical signal, and one of the wavelengths is ⁇
  • the optical signal is used as the uplink carrier of one optical network unit, and the optical signal of the other wavelength is used as the downlink carrier of another different optical network unit.
  • the optical signal of a certain wavelength generated by one light source in the prior art can be used only as a downlink carrier or an uplink carrier of a certain optical network unit.
  • the optical signal of a certain wavelength generated by the same light source is repeatedly used, and the light emitted by the same light source is divided into two parts and used as carriers of two different 0s. Therefore, for two different zero volumes, only one is used.
  • the light source can generate two optical carrier signals, which can effectively reduce the number of light sources.
  • FIG. 5 is a flowchart of Embodiment 2 of an optical transmission method capable of reducing the number of light sources according to the present invention. As shown in FIG. 5, this embodiment includes:
  • Step 100 Using a light source to generate a group of optical signals of different wavelengths, respectively performing power branching on part or all of the generated optical signals to generate two sets of optical signals having one or more same wavelengths, that is, generating the first branch. a first set of optical signals of the optical signal and a second set of optical signals of the second branched optical signal;
  • Step 200 Wavelength division multiplexing the two sets of optical signals respectively to form two mixed optical signals respectively including the first group of optical signals and the second group of optical signals of the two sets of optical signals, and transmitting through independent optical media ;
  • Step 300 Cross-routing the two mixed optical signals to form a carrier group signal composed of different wavelengths, wherein carrier group signals composed of different wavelengths respectively serve as carriers of different optical network units.
  • the present embodiment is the same as the embodiment of FIG. 4 in that the light generated by the light source is repeatedly used, but the embodiment is directed to a set of light sources having different wavelengths, and one or more of the light sources of the set of light sources are used.
  • the method of FIG. 4, that is, the signal power generated by the same light source is branched into two paths having the same wavelength, so that one set of optical signals can be separated into two sets of optical signals, and the two sets of optical signals have the same wavelength of one or more optical signals.
  • the two sets of optical signals After being separated into two sets of optical signals, the two sets of optical signals are separately wavelength-multiplexed to form two mixed optical signals, and then the two mixed optical signals are respectively cross-routed, such that one of the set of light sources Or two light sources of the same wavelength generated by multiple light sources respectively As a carrier of different 0.
  • the two sets of optical signals are separately wavelength-multiplexed to form two mixed optical signals, and then the two mixed optical signals are respectively cross-routed, such that one of the set of light sources Or two light sources of the same wavelength generated by multiple light sources respectively As a carrier of different 0.
  • FIG. 12 or FIG. 13 for easy understanding.
  • This embodiment is also based on the method of reusing wavelengths.
  • N light sources For a wavelength division multiplexing system with N zero volumes, at least N light sources need to be set.
  • the wavelengths of the continuous light emitted are respectively ⁇ 1 ⁇ 2 ⁇ ⁇ , and the light of the one wavelength is repeatedly used to divide the light of the two wavelengths into two groups, each group having a different wavelength;
  • the first group of optical signals ⁇ 1 ⁇ 2 is input into downlink carrier-bearing downlink data, wherein each downlink carrier corresponds to one volume;
  • the second group of optical signals ⁇ ⁇ 2 is used as an uplink carrier carrying uplink data, Each of the uplink carriers corresponds to one volume;
  • the two groups of optical signals after wavelength division multiplexing are subsequently cross-routed, so that the uplink carrier and the downlink carrier output to each 0 are different, for example, the first group is and a second optical signal ⁇ optical signals are used as the 0 2 and 1, uplink carrier;
  • a group of light sources may be implemented generating ⁇ different 0, the downlink data carrier.
  • the two sets of optical signals generated are exactly the same, and a total of one light source is required.
  • the optical signals of the two groups in the embodiment of FIG. 1 are not identical, as shown in FIG.
  • the light sources generate two sets of optical signals each of which includes one wavelength, and the light signals of different wavelengths generated by the first one light source are a group, and the light signals of different wavelengths generated by the latter one light source are the second group.
  • the number of zero volumes when there is a zero TOM system, when the number of zero volumes is large, that is, when N is relatively large, only about N light sources are used, and the number of light sources is about the same as that of the ordinary TOM PON system. It can be reduced by half, which can reduce the number of light sources used in the network, which can effectively reduce costs.
  • the present invention can be realized by using a simple and simple device. Compared with the prior art scheme 2, the present invention can achieve a reduction in the number of light sources at a lower cost, and due to the wavelength of the uplink and downlink carriers. Different from each other, the quality of signal transmission is greatly improved compared with the prior art solution 1.
  • FIG. 6 is a flowchart of Embodiment 3 of an optical transmission method capable of reducing the number of light sources according to the present invention. 6 is similar to FIG. 5, and has the same function as that of FIG. 5, but the wavelength division multiplexing process is further refined, and two sets of optical signals are respectively used as an uplink carrier and a downlink carrier, and the downlink data is modulated to the downlink carrier, as shown in FIG. Shown that this embodiment includes:
  • Step 1 00 Using a light source to generate a group of optical signals of different wavelengths, respectively performing power branching on part or all of the generated optical signals to generate two or more optical signals having one or more same wavelengths, that is, generating the first a first set of optical signals of the branched optical signal and a second set of optical signals comprising the second branched optical signal;
  • Step 1 1 The first group of optical signals of the two sets of optical signals are used as downlink carriers, and the downlink data is separately modulated into the first group of optical signals; and the second group of the two sets of optical signals is used.
  • the signal is used as an uplink carrier carrying uplink data;
  • Step 200 Wavelength division multiplexing the two sets of optical signals to form two mixed optical signals respectively including the first group of optical signals and the second group of optical signals;
  • Step 31 Cross-routing the two channels of mixed optical signals to generate a plurality of carrier group signals, where each of the carrier group signals includes two optical signals of different wavelengths, and each carrier group signal includes two Optical signals of different wavelengths belong to the two mixed optical signals respectively;
  • Step 320 Two optical signals having different wavelengths in each carrier group signal respectively serve as an uplink carrier and a downlink carrier of the same optical network unit.
  • two sets of optical signals are respectively used as an uplink carrier and a downlink carrier, and the downlink data is modulated into one of the optical signals, and different optical network units of the different carrier group signals are received, and the uplink data is respectively modulated to the carrier.
  • On the uplink carrier in the group signal it is sent up through the received reversible path.
  • two sets of optical signals are cross-routed, and ⁇ 2 of the first group of optical signals and the second group of optical signals of the two sets of optical signals are respectively used as illustrated in the embodiment of FIG.
  • each carrier group signal is The two or two light wave signals adjacent to the wavelength are composed.
  • each carrier group signal is composed of two optical signals separated by wavelengths. It should be understood by those skilled in the art that there are various ways of cross-routing, as long as the optical signals of different wavelengths are respectively combined into one group, so as to satisfy each cross-combined signal as the same ONU. The requirements for different downlink carrier wavelengths.
  • FIG. 7 is a flow chart of Embodiment 4 of an optical transmission method capable of reducing the number of light sources according to the present invention. 7 is different from FIG. 6. As shown in FIG. 7, this embodiment includes:
  • Step 1 00 Using a light source to generate a group of optical signals of different wavelengths, and performing power branching on part or all of the generated optical signals respectively, generating two sets of optical signals having one or more same wavelengths, that is, generating the first a first set of optical signals of a branched optical signal and a second set of optical signals comprising a second branched optical signal;
  • Step 1 1 The first group of optical signals of the two sets of optical signals are used as downlink carriers, and the downlink data is separately modulated into the first group of optical signals; and the second group of the two sets of optical signals is used.
  • the signal is used as an uplink carrier carrying uplink data;
  • Step 120 Cross-coupling a signal modulated with downlink data and the second group of optical signals to generate a plurality of carrier group signals, wherein each of the carrier group signals is coupled to two optical signals of different wavelengths;
  • Step 21 Cross-routing a plurality of carrier group signals generated after the two sets of optical signals are cross-coupled to form two mixed optical signals respectively including the first group of optical signals and the second group of optical signals of the two sets of optical signals. Transmitting the two mixed optical signals through an independent optical medium;
  • Step 220 Cross-routing the two mixed optical signals to recover the multiple carriers a group signal, wherein each of the carrier group signals includes two optical signals of different wavelengths, and the optical signals of the two different wavelengths included in each of the carrier group signals respectively belong to the two mixed optical signals;
  • Step 320 The multiple carrier group signals after the cross routing are used as carriers of different optical network units.
  • the first group of optical signals and the second group of optical signals are first cross-coupled to generate carrier group signals, each carrier group signal comprising a certain one of the first group of optical signals and the second group of optical signals
  • An uplink carrier signal having a different wavelength such as ⁇ 3 of the first group of optical signals and the second group of optical signals, is cross-coupled into a first carrier group signal; ⁇ 2 of the first group of optical signals and ⁇ of the second group of optical signals 4 cross-coupling into the second carrier group signal; ...; and ⁇ 2 of the second group of optical signals of the first group of optical signals is cross-coupled into the second carrier group signal, and then through a wavelength division multiplexing
  • the device for example, cross-routes the combined signals through a 2 ⁇ port AWG device, and outputs the two mixed optical signals after wavelength division multiplexing.
  • FIG. 14 For details, refer to the embodiment shown in FIG. 14.
  • a cross-coupling step is added before wavelength division multiplexing of the two sets of optical signals, and a 2 ⁇ ⁇ coupling device can be used for cross-coupling, which can further reduce the number of wavelength division multiplexing devices and reduce the cost.
  • using one set of optical signals of different wavelengths generated by a plurality of light sources to generate one or more optical signals of the same wavelength may be: setting a light source that generates light signals of different wavelengths, each light source is generated.
  • the optical signal power is branched into two paths, one branch is used as a downlink carrier carrying downlink data, and the other branch is used as an uplink carrier carrying uplink data;
  • the optical signal generated by the source is composed of the N optical signals as the downlink carrier after the optical signal power is branched, and the first group of optical signals is formed, and the optical signals generated by the N light sources are branched by the optical signal power to be the N of the uplink carrier.
  • the optical signals constitute a second group of optical signals, as shown in FIG. 10, FIG.
  • the remote node that receives the two-way hybrid optical signal after the wavelength division multiplexing subsequently cross-routes the two mixed optical signals to form a carrier group signal, and each group of carrier group signals respectively belong to the two
  • the two optical signals of the mixed optical signal are composed, wherein the wavelengths of the two optical signals in each group of carrier signals are different, that is, as long as the optical signals of the two different mixed optical signals and different wavelengths can be combined into one group, the wavelength They may be adjacent to each other or separated by two or two, and will not be described herein.
  • the two sets of optical signals having one or more optical signals of the same wavelength generated by using a plurality of light signals generated by the plurality of light sources may further be: setting N+1 light beams of different wavelengths.
  • the light source of the signal, the power of the optical signal generated by each of the N-1 light sources in the middle is branched into two paths, thereby generating 2N-2 optical signals; the first one of the N+1 light sources and the middle N-
  • the N-1 optical signal after the branching of one light source constitutes the first group of optical signals, and the N-1 optical signals separated by the N-1 light sources among the N+1 light sources and the N+1th light source are generated.
  • the optical signal constitutes a second group of optical signals, as shown in FIG.
  • the method of grouping is mainly based on the actual design.
  • the remote node performs cross-routing, it is difficult to combine the ⁇ ⁇ of the first group of optical signals and the in-line cross-route of the second group of optical signals to achieve optical wavelength combination output.
  • the N+1th light source is added, so that the signal carrying the downlink data of the second light source and the uplink carrier signal of the N+1th light source can be combined into the second carrier group signal, thereby reducing the design complexity.
  • FIG. 8 is a flow chart of Embodiment 5 of the optical transmission method capable of reducing the number of light sources according to the present invention. As shown in Figure 8, this embodiment includes:
  • Step 1 000 A mixed optical signal comprising a plurality of different wavelengths, the power is branched into two mixed optical signals having the same wavelength as the mixed optical signal;
  • Step 2000 After cross-routing the optical signals of different wavelengths in the two mixed optical signals, forming carrier group signals composed of different wavelengths, respectively serving as carriers of different optical network units.
  • the remote node unit includes a mixed optical signal ⁇ 2 sau, X 3u ⁇ ( N+1 ) u having different wavelengths. Dividing into two paths, and then performing cross-routing on the two optical signals to form a plurality of carrier group signals, and using the carrier group signals as the uplink carriers of different optical network units. In this embodiment, two uplink carriers are sent to each optical network unit.
  • each optical network unit will occupy 3 carrier signals.
  • the method described in this embodiment is used to split the mixed optical signal into two paths and use the cross-route as the uplink carrier of different optical network units.
  • the system requires at least N light sources. As shown in the embodiment of Fig. 18, but no more than 2N light sources, as shown in the embodiment of Fig. 17.
  • FIG. 9 is a flowchart of Embodiment 6 of the optical transmission method capable of reducing the number of light sources according to the present invention. As shown in Figure 9, this embodiment includes:
  • Step 1 1 00. Branching at least one mixed optical signal power of the multiple mixed optical signals into two mixed optical signals; each of the mixed optical signals of the multiple mixed optical signals includes a plurality of different wavelengths;
  • Step 21 00 Cross-routing the remaining mixed optical signals of the unpowered branches of the multiplexed optical signal with the two or more mixed optical signals after the power branching, and forming carrier group signals composed of different wavelengths, respectively, as different Carrier of the optical network unit.
  • FIG. 8 is a mixed optical signal
  • FIG. 9 is a multi-channel mixed optical signal.
  • One of the mixed optical signals is separated according to the method of FIG. 8.
  • FIG. 8 is the separated two.
  • the hybrid optical signal of the road is cross-routed.
  • the mixed optical signal after the power split (power branch) and the remaining optical signals are not cross-routed.
  • the multi-channel mixed optical signal may have the same wavelength. As shown in the embodiment of FIG. 20, the wavelength of the first mixed optical signal of the two mixed optical signals is ⁇ 2 , respectively.
  • the wavelength of the second mixed optical signal is ⁇ 1 ⁇ 2 ⁇ ⁇
  • the subscript "d” in the figure represents the downlink carrier
  • the “u” represents the upper
  • the two mixed optical signals have the same N-1 wavelengths.
  • the wavelengths of the first mixed optical signals of the two mixed optical signals are ⁇ 1 ⁇ 2 ⁇ ⁇
  • the wavelengths of the second mixed optical signals are ⁇ ⁇ +1 and ⁇ ⁇ + 2 ⁇ 2 ⁇ respectively.
  • the subscript "d” in the figure indicates the downlink carrier
  • "u” indicates the uplink carrier.
  • the wavelengths of the two mixed optical signals are different and will not be described in detail.
  • FIG. 10 is a schematic structural diagram of Embodiment 1 of an optical line terminal according to the present invention.
  • the embodiment includes a light source module 1 that generates N optical signals of different wavelengths, for example, where the light source module 1 includes N laser diodes (LDs) for generating different ones.
  • the optical signals of the wavelengths are denoted as the first LD, the second LD...the Nth LD, and the generated N different wavelength optical signals are denoted as ⁇ ⁇ 2 ⁇ ⁇ .
  • a photodiode can be used.
  • the carrier group signal of each optical network unit includes different downlink carriers and uplink carrier wavelengths, the uplink carrier transmitted by the certain volume received in the receiving module 4 is different from the wavelength of the downlink carrier transmitted to the zero volume. Therefore, wavelength reuse can be achieved without affecting the uplink and the downlink.
  • the embodiment further includes: a processing module 2 connected to the light source module 1 for using a group of optical signals having different wavelengths generated by the light source module 1 to respectively power part or all of the set of optical signals generated by the light source module 1 Branching, forming a first group of optical signals including a first branched optical signal (at which time no data is modulated on the first set of optical signals) and a second set of optical signals including a second branched optical signal, the two sets of optical signals having a Or a plurality of the same wavelength, such as the first branch optical signal and the second branched optical signal having the same wavelength, wherein the first group of optical signals is used as a downlink carrier for modulating downlink data, and the second group of optical signals is used as an uplink carrier; 2 further comprising a modulation function, modulating the downlink data into the first group of optical signals, and modulating the downlink data of each optical network unit to a corresponding one of the wavelengths.
  • a processing module 2 connected to the light source module 1 for using a group
  • the wavelength division multiplexing module 3 is connected to the processing module 2, and is configured to separately perform wavelength division multiplexing on the optical signal modulated with the downlink data and the second group optical signal to form the first group of lights respectively modulated with the downlink data.
  • the signal and the two mixed optical signals used as the second group of optical signals of the uplink carrier, and the downlink data is modulated in the first group of optical signals included in the two mixed optical signals.
  • the existing arrayed waveguide grating (Arrayed Waveguide Grating, AWG for short) can be used for wavelength division multiplexing. As shown in Fig. 10, the first AWG and the second AWG device are used to implement the wavelength division multiplexing/demultiplexing.
  • the processing module in this embodiment may be further refined, including:
  • the ion-dividing module 23 is connected to the light source module 1 for performing power branching on part or all of a group of optical signals having different wavelengths generated by the light source module 1, and the first branch optical signal is provided as a downlink carrier for modulating downlink data.
  • the modulation sub-module 21, the optical signal of the second branch is provided as an uplink carrier to the uplink carrier sub-module 22.
  • the ion-dividing module 23 may be a virtual module having a plurality of discrete branching elements or an integrated module having a plurality of branching components, wherein each of the branching components power branches the optical signals generated by one light source to generate two wavelengths. The same optical signal.
  • the modulation sub-module 21 is connected to the wavelength division multiplexing module 3 for receiving a first group of optical signals, and the first group of optical signals includes a first branch optical signal provided by the separation sub-module 23.
  • the modulation sub-module 21 modulates the downlink data to the first group of optical signals, and each of the optical network units corresponds to one of the first group of optical signals.
  • the first group of optical signals carrying the downlink data is added to the downlink (short d) flag, as shown in FIG. 10, the first group of optical signals is ⁇ ⁇ , ⁇ 1 ⁇ ⁇ ⁇ ;
  • a Mach-Zehnder modulator (Mach-Zehnder) is used.
  • Modulator is used as the modulation device; the modulation sub-module 21 can be a virtual module composed of a plurality of discrete Mach-Zehnder modulators, or an integrated module including a plurality of Mach-Zehnder modulators.
  • the uplink carrier sub-module 22 is connected to the wavelength division multiplexing module 3, and uses the generated second optical signals of different wavelengths as the uplink carrier; as shown in FIG. 10, the uplink carrier signal is added to the uplink.
  • the second set of optical signals are denoted as ⁇ lu , ⁇ 2 ⁇ , , ⁇ Nu ; the first set of optical signals and the second set of optical signals add up and down signs, but for ⁇ lu , ⁇ 1 (1 represents light of the same wavelength ⁇ , but is used for the downlink carrier and the uplink carrier, respectively, and so on.
  • the number of carriers of the number is equal to the number of optical network units, and the first group of optical signals that are provided to the modulation sub-module 21 for use as the downlink carrier is the first branch optical signal; if the optical signal portion generated by the light source module 1 performs power branching or power branching
  • the number of carriers of the optical signal is smaller than the number of optical network units, and the first group of optical signals provided to the modulation sub-module 21 for use as the downlink carrier further includes an unbranched optical signal, which may be provided by the separation sub-module 23. It can also be provided directly by the light source module 1.
  • the first group of optical signals that are provided to the uplink carrier sub-module 22 for use as the downlink carrier is the first a branch optical signal; if the light source module
  • the number of carriers of the optical signal portion of the generated optical signal portion for power branching or power branching is smaller than the number of optical network units, and the second group of optical signals that are provided to the uplink carrier sub-module 22 for use as the uplink carrier further include unbranched optical signals.
  • This unbranched optical signal may be provided by the separation sub-module 23 or directly by the light source module 1.
  • the generated N light sources are repeatedly used, and the optical signals of different wavelengths generated by one set of light sources are divided into two groups, one group is used for carrying downlink data, and the other group is used as an uplink carrier, and the same light source is generated.
  • the wavelength light is used for the uplink and downlink data carriers of different optical network units (0), and the light generated by the N light sources can be used as the carrier of the uplink and downlink data for N different ONUs.
  • a system with N zero volumes needs to use 2N light sources.
  • only N light sources are required to provide both uplink and downlink data carriers, thereby effectively reducing the number of light sources used in the network.
  • the system cost is reduced.
  • the present invention can reduce the number of light sources at a lower cost, and because the wavelengths of the uplink and downlink carriers are different, the quality of the signal transmission is higher than the existing one.
  • a technical solution has been greatly improved.
  • FIG. 11 is a schematic structural view of Embodiment 2 of an optical line terminal according to the present invention.
  • This embodiment is similar to FIG. 10, and the same function is not described in detail, but the difference is that the embodiment further includes: a cross-coupling module 105, which is connected to the processing module 102 and the wavelength division multiplexing module 103, and is used for Two optical signals respectively located in the two sets of optical signals and having different wavelengths are cross-coupled to generate a plurality of carrier group signals.
  • a cross-coupling module 105 which is connected to the processing module 102 and the wavelength division multiplexing module 103, and is used for Two optical signals respectively located in the two sets of optical signals and having different wavelengths are cross-coupled to generate a plurality of carrier group signals.
  • the first carrier group signal ⁇ ⁇ ⁇ 2 taken after cross-coupling in Figure 1 1 , the second carrier group letter No. ⁇ ⁇ ⁇ , ... the second carrier group signal Nd lu , the wavelength division multiplexing module 103 of this embodiment may be a 2 ⁇ ⁇ AWG device, for details, refer to the related description in the embodiment of FIG. 7 , Compared to the embodiment, the reduction of one AWG device is more cost effective.
  • the optical line terminal (0LT) in Fig. 13 is a different structure from Fig. 10 and Fig. 11, which will be explained and illustrated in the embodiment of Fig. 13.
  • FIG. 12 is a schematic structural diagram of Embodiment 1 and a remote node unit of an optical transmission system capable of reducing the number of light sources according to the present invention.
  • the remote node unit includes: a cross-routing module, which is connected to the input 2-way mixed optical signal, and is used for cross-routing the input 2-way mixed optical signal to generate multiple carrier group signals, and multiple carrier groups are generated.
  • the signals respectively serve as carriers of different optical network units; wherein each of the two mixed optical signals includes two carriers of different wavelengths, and the two mixed optical signals have one or more carriers of the same wavelength. , wherein one of the mixed optical signals is also modulated with downlink data.
  • the cross-routing module implements the cross-routing function using the third AWG device as shown in FIG.
  • the embodiment provides an optical transmission system capable of reducing the number of light sources, including an optical line terminal ⁇ , a remote node unit ⁇ , and a plurality of optical network units C, which are sequentially connected, and the optical line terminal ⁇ see the description of the embodiment of FIG. 10, Similarly, in Fig. 10, the optical line terminal A connects the generated two-way mixed optical signal to the remote node unit B through two independent optical media.
  • N light sources emit N optical signals, where the optical signal emitted by the light source is continuous light, and some or all of the N optical signals are branched by power to form a first optical signal including the first branch.
  • the group optical signal forms a first group of optical signals including the first branched optical signal and a second set of optical signals including the second branched optical signal, and modulates the downlink data to the optical signal of the first group of optical signals modulated with downlink data
  • Wavelength division multiplexing is performed by the first AWG at the 0LT; the second group of optical signals is wavelength-multiplexed directly through the second AWG at the 0LT as an uplink carrier that is sent to the optical network unit.
  • the multiplexed two-way mixed optical signals are respectively transmitted by two optical fibers, one transmission
  • the optical signal carrying the downlink data is transmitted, and the other is transmitted as the optical signal of the uplink carrier.
  • the first group of optical signals may only include the first branched optical signal (the number of the light sources M is equal to the number N of the optical network units or the power of all the optical signals generated by the light source is branched).
  • the first set of optical signals may include the first A branch optical signal in turn includes other optical signals (the number of light sources M is greater than the number N of optical network units or power branches of the optical signals generated by the light source).
  • the second group of optical signals may only include the second branch optical signal (the number of light sources M is equal to the number N of optical network units or the power of all the optical signals generated by the light source is branched).
  • the second set of optical signals may include the second branch.
  • the optical signal in turn includes other optical signals (the number of light sources M is greater than the number N of optical network units or the power branches of the optical signals generated by the light source).
  • the two fibers are connected to a 2 ⁇ third AWG device. Due to the cross-route characteristics of the AWG device, one of the output ports will output a downlink data signal and a carrier signal of the uplink carrier, respectively. As shown in FIG. 12, the first output port outputs ( ⁇ 1 (1 , ⁇ 2 ⁇ ), the second output port outputs ( ⁇ ⁇ , 3u ), ..., the Nth output port output ( ⁇ ⁇ , Lu ) Since the Free Spectral Range (FSR) of each AWG device is fixed, the cross-route of wavelengths can be realized only when a certain operating wavelength relationship is satisfied, and a carrier group signal composed of a plurality of different wavelengths is output. In order to achieve this cross-routing feature, this embodiment requires a reasonable selection of the operating wavelength of the N light sources and the FSR of the third AWG device.
  • FSR Free Spectral Range
  • Each carrier group signal output by the remote node unit B corresponds to one of the plurality of optical network units (0) C, for example, the output port 1 corresponds to the first optical network unit 1, and the output port N corresponds to the first N optical network unit.
  • Each optical network unit such as the first optical network unit, includes: a filtering module, connected to the remote node unit B, configured to filter the received carrier group signal, and separate two different wavelengths in the carrier group signal, such as The first optical network unit in FIG. 12 is filtered by the TOM device. It should be noted that the present embodiment includes a filtering module, but when used in other network structures, filtering is not necessarily required, and the filtering module is not needed at this time;
  • a modulation module connected to the filtering module, configured to receive the filtered uplink carrier signal, modulate the uplink data, and send the reversible path of the receiving channel to the optical line terminal through the remote node,
  • the uplink carrier signal is sent to a modulation device, such as the relatively low cost electro-absorption modulator (EAM) shown in FIG. 12, to modulate the uplink data.
  • the modulated uplink signal is sent to the receiving (Rx) module of the 0LT via the reversible path;
  • the downlink receiving module is connected to the filtering module, and is configured to receive a downlink carrier signal carrying downlink data, and perform detection to obtain downlink data, and send the downlink data signal in the first carrier group signal to the first optical network, as shown in FIG.
  • the receiving module inside the unit.
  • the embodiment provides an optical transmission system and a remote node unit capable of reducing the number of network light sources.
  • N N different wavelengths of light sources
  • each group of two different wavelengths of light is generated by power branching of the light source signals.
  • the signal and the cross-route of the subsequent remote node unit realize that the same wavelength optical signal generated by the same light source is used for the uplink and downlink carriers of different optical network units (0 volumes) respectively, and a set of light sources can generate different 0s.
  • the uplink and downlink carriers Compared with the prior art scheme 2, the invention can realize the reduction of the number of light sources with a simple cost and a mature simple device, and the quality of the reception is higher than that of the prior art scheme 1 because the wavelengths of the uplink and downlink carriers are different. The ratio has been greatly improved.
  • FIG. 13 is a schematic structural diagram of Embodiment 2 of the optical transmission system capable of reducing the number of light sources, Embodiment 2 of the remote node unit, and Embodiment 3 of the optical line terminal. 13 is similar to the embodiment of FIG. 12, except that the internal structure of the optical line terminal, the two mixed optical signals generated by the optical line terminal A1 in this embodiment do not have the same wavelength, and the remote node unit B inputs The wavelengths of the two mixed optical signals are not exactly the same. As can be seen from the embodiment of FIG. 12, when the third AWG device in the remote node unit B of FIG. 12 cross-routes the input optical signal, the last output port realizes the optical wavelength combination output pair of ( ⁇ ⁇ , lu ).
  • the design of the third AWG is difficult to implement.
  • (N+1) light sources of different wavelengths are used at the optical line terminal A1, and the (N+1) different wavelengths are used.
  • the light sources are divided into two groups, the first set of optical signals includes ⁇ ld , ⁇ 2 ⁇ ⁇ ⁇ , and the second set of optical signals includes ⁇ 2 ⁇ , ⁇ 3u ⁇ ( N +1 ) u , which is performed at the remote node (RN) unit B1
  • the output port N outputs ( ⁇ ⁇ , ⁇ (N+1) U ) to the Nth optical network unit in the optical network unit CI, ⁇ ⁇ and ⁇ ow ) u respectively as the Nth optical network unit
  • the output port N outputs ( ⁇ ⁇ , ⁇ (N+1) U ) to the Nth optical network unit in the optical network unit CI, ⁇ ⁇ and ⁇ ow ) u respectively as the Nth optical network unit
  • FIG. 14 is a schematic structural diagram of Embodiment 3 of an optical transmission system capable of reducing the number of light sources according to the present invention.
  • the optical line terminal in this embodiment is similar in structure to the embodiment of Fig. 11.
  • the system of the present embodiment is different from the embodiment of FIG. 12 and FIG. 13.
  • the optical line terminal A2 is internally cross-coupled, and a wavelength division multiplexing device is used to complete the wave division of the two sets of optical signals after cross-coupling.
  • a wavelength division multiplexing device is used to complete the wave division of the two sets of optical signals after cross-coupling.
  • the wavelength division device of the remote node unit in the embodiment of FIG. 12 to FIG. 1 only implements cross routing using a 2 ⁇ N AWG device, but those skilled in the art should understand that the wavelength division device of the remote node unit also According to the same structural principle inside the 0LT in Figure 10-11, the two 1 x N AWG devices are separately wavelength-multiplexed with the two mixed optical signals, and then the wavelength division multiplexed The signals are cross-routed, and N carrier group signals are formed and sent to the respective ONUs.
  • FIG. FIG. 15 is a schematic structural diagram of Embodiment 4 of the optical transmission system capable of reducing the number of light sources according to the present invention and a third embodiment of the remote node unit.
  • the cross-routing module of the remote node unit B2 has the same function as that of FIG. 13, but different wavelengths are used to form a plurality of carrier group signals by wavelength division multiplexing after the third AWG and the fourth AWG device respectively.
  • FIG. 16 is a schematic structural diagram of Embodiment 5 of the optical transmission system capable of reducing the number of light sources according to the present invention and a fourth embodiment of the remote node unit.
  • the remote node unit in the embodiment of FIG. 16 is different from that in FIG. 12-15.
  • the remote node unit B3 includes:
  • a separating module B31 configured to mix the optical signals including N different wavelengths, and branch the power into two mixed optical signals having the same wavelength as the mixed optical signal;
  • the cross-routing module B 33 is connected to the separation module B31, and is configured to input the two mixed optical signals, and cross-route the two mixed optical signals to generate a plurality of carrier group signals, and use different carrier group signals as different An uplink carrier of the optical network unit, where each carrier group signal includes two optical signals of different wavelengths, and the optical signals of the two different wavelengths included in each carrier group signal belong to two mixed optical signals respectively.
  • the third AWG device in the embodiment of FIG. 16 implements the cross-routing function, and for the downlink signal, only the wavelength division multiplexing (TOM) device B 32 is used for wavelength division. After multiplexing, it is used as the downlink signal of each different optical network unit.
  • TOM wavelength division multiplexing
  • the carriers of the N optical network units are implemented by using N+1 light sources.
  • each of the plurality of optical network units C 3 in the embodiment corresponds to 3
  • the carrier group signals of different wavelengths, each carrier group signal includes one uplink carrier and two uplink carriers, and the structure of the optical line terminal and the optical network unit has been described in detail in the foregoing embodiments, and will not be described here.
  • this embodiment reduces about 2N light sources, which can be completed with mature devices and has low cost.
  • FIG. 17 is a schematic structural view of Embodiment 6 of an optical transmission system capable of reducing the number of light sources according to the present invention.
  • the internal structure of the remote node unit in this embodiment is similar to that of FIG. 16.
  • the optical line terminal A3 is different from the embodiment of FIG. 12 to FIG. 16.
  • the optical line terminal A3 uses 2N light sources of different wavelengths, and a set of N
  • the optical signals generated by the different wavelengths of the light source are used as the downlink carrier, and the optical signals generated by the other group of N different wavelengths are used as the uplink carrier, such as the N different wavelengths generated by the first LD to the Nth LD in the light source module A31.
  • the set of wavelength optical signals is used as the downlink carrier, and the other group of wavelength optical signals of the N different wavelengths generated by the N+1 LD to the 2N LDs in the light source module A 32 are used as the uplink carrier, and the remote node unit B4 is passed.
  • the splitting module is divided into two uplink carrier mixed optical signals, and then performs subsequent cross-routes to generate carriers of different optical network units.
  • the optical line terminal in this embodiment does not improve, but the remote node unit B4 Since the power branch and the subsequent cross-route are performed, for a system with N optical network units, 3N carrier signals can be generated by using 2N light sources, compared with the prior art. Reducing the N light sources.
  • the optical signals used as the uplink carrier generated by the one light source provide 2 uplink carriers for the optical network units after power branching, and may be N + 1 , 2N-1 light sources as above.
  • the generated optical signal used as the uplink carrier provides 2 uplink carriers for the optical network unit.
  • FIG. 18 is a schematic structural diagram of Embodiment 7 and the remote node unit of the optical transmission system capable of reducing the number of light sources.
  • the internal structure of the optical line terminal in this embodiment is the same as that of the embodiment of FIG. 14.
  • the remote node unit is similar to that of FIG. 16, and the overall structure is similar to the embodiment of FIG. 16, but FIG. 16 requires N+1 light sources, and FIG. 18 requires one.
  • the internal structure of the node unit B5 and the optical network unit C5 is similar to that of the foregoing embodiment except that the wavelengths of the carrier signals are different, and will not be described here.
  • FIG. 19 is a schematic structural diagram of Embodiment 8 and a remote node unit of the optical transmission system capable of reducing the number of light sources according to the present invention.
  • the remote node unit B6 includes:
  • a separating module B61 configured to branch power of one of the two mixed optical signals (unmodulated downlink data) into two mixed optical signals that are the same as the mixed optical signal;
  • the cross-routing module B62 is connected to the separation module B61, and is configured to cross-route the three mixed optical signals and the unpowered optical signals (modulated with downlink data) of the power branch input by the separation module B61. Generating a plurality of carrier group signals, respectively, using the plurality of carrier group signals as carriers of different optical network units, wherein each carrier group signal includes three optical signals of different wavelengths and each carrier group signal includes three different wavelengths The optical signals belong to the three-way mixed optical signal input to the cross-routing module B62, respectively.
  • the optical line terminal A3 is configured to generate two sets of optical signals by using two sets of light sources, and separately perform wavelength division multiplexing on the two sets of optical signals to form a first set of optical signals and a second set of optical signals respectively included in the two sets of optical signals.
  • Two-way mixed optical signal wherein the two sets of light sources have different wavelengths;
  • the remote node unit B6 is connected to the optical line terminal through two independent optical media, and is used for two-way mixing of the input
  • the optical signals are cross-routed to generate a plurality of carrier group signals, and the plurality of carrier group signals are respectively used as carriers of different optical network units.
  • each carrier group signal includes three carriers, which are respectively sent to the optical network unit.
  • the wavelengths of the two mixed optical signals generated by the optical line terminals are different.
  • FIG. 20 is a schematic structural diagram of Embodiment 9 of the optical transmission system capable of reducing the number of light sources according to the present invention and a seventh embodiment of the remote node unit.
  • the embodiment of Figure 20 is similar to the embodiment of Figure 19 in that an AWG device is used as the cross-routing module, but the optical line termination is different from Figure 19.
  • Optical line terminal of this embodiment Al is the same structure as the embodiment of FIG. 16.
  • the two mixed optical signals generated by the optical line terminal A1 have N-1 identical wavelengths.
  • This embodiment has the same optical line terminal A1 and optical network as the embodiment of FIG. Unit C3, but remote node unit B7 is similar to the embodiment of Fig. 19.
  • the present invention can be embodied in a variety of different forms.
  • the technical solutions of the present invention are exemplified in the following with reference to FIG. 4 to FIG. 20, which does not mean that the specific examples applied to the present invention can be limited to In the particular flowchart and embodiment structure, one of ordinary skill in the art will appreciate that the specific embodiments provided above are just a few examples of various preferred uses, and any group of optical signals are reused and divided into two groups.
  • An optical signal, each set of optical signals having different wavelengths and the two sets of optical signals having one or more identical wavelengths, and respectively transmitted through different media, and implementing two sets of optical signals as upper and lower carrier signals respectively by cross routing The embodiments are all within the scope of the claimed invention.
  • the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

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Description

光线路终端、 远端节点单元、 光传输方法及系统 本申请要求于 2007 年 10 月 25 日提交中国专利局、 申请号为 200710167350.7、 发明名称为"光线路终端、 远端节点单元、 减少光源数量 的方法及系统"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
本发明属于网络通信技术领域， 涉及一种光线路终端、 远端节点单元、 光传输方法及系统， 特别是一种波分复用系统中能够减少光网络光源数量的 光线路终端、 远端节点单元、 光传输方法及系统。 背景技术
目前光接入技术的共同特点是： 光线路终端（ Optical Line Terminal, 简称 0LT) 和光网络单元 （ Optical Network Unit, 简称 0NU)之间通过光 分路器分配光信号， 上下行载波分别使用不同的波长进行数据传输。
现有的光网络系统中存在较大的光衰耗， 并且传统的无源光网络 ( Passive Optical Network, 简称 PON )技术在传输巨离和分路 t匕等方面 都受到了限制， 各 0NU获得的上行带宽有限， 很难满足高清晰数字等高带 宽业务的需求。
针对现有光网络系统的情况， 在接入网中引入波分复用技术
(Wavelength Division Multiplex , 简称 TOM) 可以解决 PON技术的问题。 如图 1所示，每个 0NU分配 2个不同的波长，分别用于上行和下行载波的传 输。 光线路终端， 置于如图 1所示的中心局 （C0) 中， 光线路终端 （0LT) 使用多波长光源， 下行传给 0而 1， 0NU2. . . ONUn的数据分别调制到波 长为 λ 1、 λ 2、 . . . λη的光载波上后发送， 通过无源远端节点 （Remote node, 简称 RN)把信号分配给目的光网络单元， 完成下行传输。 上行传输 时， ONU间釆用 ( Wavelength-Division Multiplexing Access, 简称画 A) 解决信道竟争问题， 每个 0冊使用一个特定的波长承载上行数据， 如图 1 所示 n个 0冊分别在 λ Γ、 λ 2 . . . λη'的光载波上承载上行数据， 不需 要定时和网络同步。 上行信号通过波长光栅路由器（Wavelength Grating Router , 简称 WGR) 上传到 OLT的接收端， 如通过图 1 中的阵列波导光栅 ( Arrayed Waveguide Grating, 简称 AWG)上传到 OLT的接收端。 但是现有 的 TOM-P0N相对其他宽带接入方式， 初期投资太大， 成本过高， 其主要原因 是系统中需要使用大量的光源。 如图 1所示， 对于有 N个 0而的系统， 每个 0冊釆用不同波长作为上、 下行的载波信号， 此 TOM-P0N系统将使用 2N个光 源； 对于有些波分复用系统，每个 0而需要两个上行载波以获得较高的上行 调制信号功率， 有 N个 0冊的系统， 每个 0冊占用 3个光载波， 釆用一个波长 的下行载波， 和 2个不同波长的上行载波信号， 系统中将使用 3N个光源。 为了降低 PON 统中的光源数量， 现有技术主要通过以下两种方式：
一、 光网络单元处釆用重调制的方式
这种方式对于有 N个 0冊的系统， 每个 0NU釆用相同波长传输上下行 信号， 系统中将使用 N个光源， 光源总数目与图 1所示的系统相比可降低 一半。 具体的： 0而把来自 0LT的携带有下行数据的下行光信号分成两部 分， 一部分用于探测恢复出下行数据， 另一部分用于上行数据发送， 上行 数据重调制于此部分下行光上， 再发送回 0LT, 如图 2所示， 每个 0NU的 上下行承载于同一个波长， 0而不设置光源， 只在 0LT处设置光源。
第一种方式虽然可以降低光源的数量， 但光网络单元处釆用重调制的 方式， 在下行光上承载的下行数据对上行数据的调制会有影响， 影响系统 0LT处上行数据的接收质量。
二、 基于宽谱光源谱分割的方式
0LT处设置两个高功率的宽谱光源，釆用宽谱光源谱分割的方法为 0LT 和 0而分别提供下行光载波和上行光载波，如图 3中的宽谱光源（Broadband L i ght Source , 简称 BLS ) , 第二宽谱光源用于给 OLT提供锁波长的光源， 第一宽谱光源用于为 0而提供锁波长的光源。 宽谱光源发出的宽谱光经解 复用器 （Demul t i p l exer , DEMUX ) 进行谱分割后得到一系列窄光谱光， 注 入到一系列置于中心局内的 0LT或 0而的接收 /发送部分中产生注入锁定光 源， 如图 3所示。
上述谱分割的方式将宽频光谱分割成若干个窄光谱， 窄光谱之间存在 频谱间隙， 因此， 光源功率的利用率不高； 同时， 高功率宽谱光源器件还 不太成熟， 成本高。
现有技术中波分复用系统需要使用较多的光源， 虽然现有技术中有降 低光源数量的方式， 但同时会带来信号传输质量不高、 光源功率利用率不高 或成本较高等问题。 发明内容
本发明的第一目的是提供一种光传输方法， 用以解决现有的光网络系统 光源数量较多、 成本高及现有的降低网络光源数量的技术方案信号传输质量 不高、 光源功率利用率不高等问题， 实现降低网络中光源的数量、 提高接收 质量， 并同时降低系统的成本。
本发明的第二目的是提供一种光线路终端， 用以解决现有的光线路终端 降低网络光源数量的技术方案需要加入高功率宽谱光源器件、 光源功率利用 率不高、 成本较高或现有的技术方案接收质量不高等问题， 实现既降低网络 中光源的数量、 提高信号传输质量， 又同时降低系统的成本。
本发明的第三目的是提供一种远端节点单元， 用以解决现有的光网络系 统光源数量较多、 成本较高等问题， 实现既降低网络中光源的数量、 提高信 号传输质量， 又同时降低系统的成本。
本发明的第四目的是提供一种光传输系统， 用以解决现有的光网络系统 光源数量较多、 成本高及现有的降低网络光源数量的系统接收质量不高、 光 源功率利用率不高等问题， 实现降低网络中光源的数量、 提高信号传输质量， 并同时降低系统的成本。
为了实现本发明第一目的， 本发明一光传输方法实施方式， 利用光线 路终端上的 M个光源为 N个光网络单元提供 K个载波， 所述 M、 N和 K都为 大于 1的整数， 且1 ^>= 所述方法包括：
将 M个光源产生的 M个不同波长的光信号的部分或全部分别进行功率 分支， 形成包含第一分支光信号的第一组光信号和包含第二分支光信号的 第二组光信号， 其中， 所述第一组光信号和所述第二组光信号均具有 N个 不同波长；
将所述第一组光信号和所述第二组光信号进行交叉路由， 形成需要提供 给 N个光网络单元的 N个载波组信号， 其中， 所述 N个载波组信号共有 K个 载波， 每一个载波组信号包含第一组光信号的载波和第二组光信号的载波， 且每个载波组信号包含的载波的波长不同。
为实现本发明第二目的， 本发明光线路终端的实施方式包括产生 M个 不同波长的光源模块， 光线路终端上的 M个光源为 N个光网络单元提供 K 个载波， 所述 M、 N和 K都为大于 1的整数， 且1 ^>= 所述光线路终端 还包括：
处理模块， 用于将光源模块产生的具有不同波长的一组光信号中部分 或全部分别进行功率分支， 形成包含第一分支光信号的第一组光信号和包 含第二分支光信号的第二组光信号， 并将下行数据调制到所述第一组光信 号， 其中， 所述第一组光信号和所述第二组光信号均具有 N个不同波长， 所述第二组光信号用作上行载波；
波分复用模块， 用于分别对调制有下行数据的光信号和所述第二组光 信号分别进行波分复用， 形成分别包含调制有下行数据的第一组光信号和 用作上行载波的第二组光信号的两路混合光信号；
接收模块，用于接收 N个光网络单元的上行光信号， 其中， 每一个光网络 单元的上行光信号的载波与发送给该光网络单元的下行载波的波长不同。 为了实现本发明第三目的， 本发明一远端节点单元的实施方式包括： 交叉路由模块， 用于对输入的多路混合光信号进行交叉路由， 组成多个 由不同波长构成的载波组信号， 将多个载波组信号分别作为不同光网络单 元的载波；
其中， 所述多路混合光信号中的每路混合光信号均包含多个不同波长 的载波， 且多路混合光信号具有一个或多个相同波长的载波。
为了实现本发明第四目的， 本发明一光传输系统的实施方式包括： 依 次相连的能够产生 M个不同波长光信号的光线路终端、 远端节点单元及 N个 光网络单元，光线路终端能够为所述 N个光网络单元提供 K个载波，所述 M、 N和 K都为大于 1的整数， 且〖^>=
光线路终端， 用于产生 M 个不同波长的一组光源， 对部分或全部光源 分别进行功率分支， 生成包含第一分支光信号的第一组光信号和包含第二 分支光信号的第二组光信号， 将下行数据调制于所述第一组光信号中， 将 调制有下行数据的第一组光信号和所述第二组光信号分别进行波分复用， 形成分别包含调制有下行数据的第一组光信号和第二组光信号的两路混合 光信号；
远端节点单元， 与所述光线路终端连接， 用于对输入的两路混合光信号 进行交叉路由， 组成多个由不同波长构成的载波组信号， 将多个载波组信号 分别作为不同光网络单元的载波， 其中， 每一个载波组信号包含两路混合 光信号中未调制下行数据的混合光信号的一个载波和两路混合光信号中调制 有下行数据的混合光信号的一个载波。
综上所述， 本发明提出了一种光线路终端、 远端节点单元、 能够降低 网络光源数量的光传输方法及系统， 各技术方案重复利用产生的光源将一 个或一组光源产生的光信号分成了相同的两路或有重叠波长的两组， 将一 路混合光信号功率分支成了相同的两路， 将两路或两组光信号分别作为不 同光网络单元的载波。 对于两组光信号形成的混合光信号通过后续的交叉 路由，实现了将同一光源产生的同一波长光分别用于不同光网络单元（ 0而） 的载波。 现有技术中有 N个 0而的系统需要使用 2N或 3N个光源， 经过验 证， 本发明各实施例只需设置大约 N个光源既可， 因此， 可以有效的减少 网络中所使用的光源数量， 进而降低系统成本， 并且， 本发明釆用成熟的 简单器件即可实现， 波分复用可以釆用现有的阵列波导光栅 （Ar rayed Wavegui de Gra t ing , 简称 AWG) , 调制可以釆用成熟的马赫曾德尔调制器 ( Mach-Zehnder Modul a tor , 简 称 ΜΖΜ ) 或 者 电 吸收调 制 器 ( e lec t ro-absorpt ion modula tor , 简称 EAM ) 等, 与现有技术方案 2相 波的波长不相同， 所以信号传输的质量比现有技术方案 1相比又有很大提 高。
下面通过附图和实施例， 对本发明的技术方案做进一步的详细描述。 附图说明
图 1为现有的波分复用系统结构示意图；
图 2为现有的基于重调制的无源光网络系统结构示意图；
图 3为现有的基于宽谱光源谱分割的无源光网络系统结构示意图;
图 4为本发明能够减少光源数量的光传输方法实施例一流程图； 图 5为本发明能够减少光源数量的光传输方法实施例二流程图； 图 6为本发明能够减少光源数量的光传输方法实施例三流程图； 图 7为本发明能够减少光源数量的光传输方法实施例四流程图； 图 8为本发明能够减少光源数量的光传输方法实施例五流程图； 图 9为本发明能够减少光源数量的光传输方法实施例六流程图； 图 10为本发明光线路终端实施例一结构示意图；
图 11为本发明光线路终端实施例二结构示意图； 图 12为本发明能够减少光源数量的光传输系统实施例一及远端节点单元 实施例一结构示意图；
图 1 3为本发明能够减少光源数量的光传输系统实施例二、 远端节点单元 实施例二及光线路终端实施例三结构示意图；
图 14为本发明能够减少光源数量的光传输系统实施例三结构示意图； 图 15为本发明能够减少光源数量的光传输系统实施例四及远端节点单元 实施例三结构示意图；
图 16为本发明能够减少光源数量的光传输系统实施例五及远端节点单元 实施例四结构示意图；
图 17为本发明能够减少光源数量的光传输系统实施例六结构示意图； 图 18为本发明能够减少光源数量的光传输系统实施例七及远端节点单元 实施例五结构示意图；
图 19为本发明能够减少光源数量的光传输系统实施例八及远端节点单元 实施例六结构示意图；
图 20为本发明能够减少光源数量的光传输系统实施例九及远端节点单元 实施例七结构示意图。 具体实施方式
图 4 为本发明能够减少光源数量的光传输方法实施例一流程图。 如图 4 所示， 本实施例包括：
步骤 1 0.将一个光源产生的光信号， 功率分支为两路光信号； 步骤 20.将所述两路相同波长的光信号分别作为不同光网络单元的载 波。
具体的， 可以将同一光源发出的光信号功率分支为两路相同波长的光 信号， 分别作为不同光网络单元的上行载波和下行载波， 如利用波长入 的 一个光源功率分支产生两路波长均为 A t的光信号， 并将其中一路波长为 λ 的光信号作为某一光网络单元的上行载波，将另一路波长为 的光信号作 为另一不同光网络单元的下行载波。 与现有技术不同， 现有技术中一个光 源产生的某波长的光信号， 只利用一次， 只能作为某一个光网络单元的下 行载波或上行载波。 本实施例重复利用同一光源产生的某波长的光信号， 将同一光源发出的光，分成两部分，并分别作为两个不同 0而的载波， 因此， 对于两个不同的 0冊， 只利用一个光源， 即可产生两个光载波信号， 从而可 有效减少光源的数量。
图 5为本发明能够减少光源数量的光传输方法实施例二流程图。 如图 5 所示， 本实施例包括：
步骤 100.利用光源产生不同波长的一组光信号， 对产生的这组光信号 的部分或全部分别进行功率分支， 生成有一个或多个相同波长的两组光信 号， 即生成包含第一分支光信号的第一组光信号和第二分支光信号的第二 组光信号；
步骤 200.将两组光信号分别进行波分复用， 形成分别包含所述两组光 信号中第一组光信号和第二组光信号的两路混合光信号， 通过独立的光媒 介进行传输；
步骤 300.将所述两路混合光信号进行交叉路由， 组成由不同波长构成 的载波组信号， 其中， 由不同波长构成的载波组信号分别作为不同光网络 单元的载波。
本实施例与图 4实施例相同之处均是重复利用光源产生的光， 但本实 施例针对的是一组波长各不相同的光源， 将这一组光源中的一个或多个光 源釆用图 4的方法， 即同一光源产生的信号功率分支为波长相同的两路， 这样， 一组光信号可以分离成两组光信号， 该两组光信号有一个或多个光 信号的波长相同。 在分离为两组光信号后， 将两组光信号分别进行波分复 用， 形成两路混合光信号， 后续再将两路混合光信号分别进行交叉路由， 这样， 这一组光源中的一个或多个光源产生的两路波长相同的光信号分别 作为不同 0而的载波。 本实施例具体可参见图 12或图 1 3实施例以便于理 解。
本实施例还是基于重复利用波长的方式， 釆用本实施例所述的方法， 对于有 N个 0冊的波分复用系统， 最少只需设置等于 N个光源。 如， 设置 N个 光源时， 发出的连续光波长分别为 λ 1 λ 2 λ Ν , 重复利用此 Ν个波 长的光， 将这 Ν个波长的光分成两组， 每组有 Ν个不同波长； 将第一组光信 号 λ 1 λ 2 入^乍为下行载波承载下行数据， 其中， 每一个下行载 波对应一个 0冊； 第二组光信号 λ λ 2 入^乍为承载上行数据的上 行载波， 其中， 每一个上行载波对应一个 0冊； 后续会对波分复用后的两组 光信号进行交叉路由， 使得输出给每一个 0而的上行载波和下行载波不同， 例如，将上述第一组光信号的 和第二组光信号的 λ 2分别用作 0而1的下、 上行载波； 第一组光信号的 λ 2和第二组光信号的入3分别用作 0而2 的下、 上行载波； ... ...； 而第一组光信号的 λ Ν和第二组光信号的入 分别用作 0NUN 的下、 上行载波， 实现了将同一光源产生的同一波长光分别用于不同光网 络单元 （0冊） 的上行和下行数据载波， 利用 Ν个数量的一组光源即可以实 现产生 Ν个不同 0冊的上、 下行数据的载波。 如图 12实施例所示， 产生的两 组光信号完全相同， 共需 Ν个光源； 图 1 3实施例的两组光信号则不完全相 同， 如图 1 3所示， 需要利用 N+1 个光源， 产生每组包含 Ν个波长的两组光 信号， 前 Ν个光源产生的不同波长光信号为一组， 后 Ν个光源产生的不同波 长光信号为第二组。
通过上述举例可知， 本实施例在有 Ν个 0而的 TOM系统， 在 0冊的数 量较多时， 即 N比较大时只使用大约 N个光源， 与普通的 TOM PON系统相 比， 光源数量大约可以减少一半， 可以减少网络中所使用的光源数量， 从 而可以有效的降低成本。
本发明釆用成熟的简单器件即可实现， 与现有技术方案 2相比， 本发 明釆用较低的成本即可以实现减少光源数量， 并且由于上下行载波的波长 不相同， 所以信号传输的质量比现有技术方案 1相比又有很大提高。
图 6为本发明能够减少光源数量的光传输方法实施例三流程图。 图 6与 图 5类似， 具有与图 5相同的功能， 但是波分复用过程进一步细化， 将两组 光信号分别作为上行载波和下行载波， 并调制下行数据到下行载波， 如图 6 所示， 本实施例包括：
步骤 1 00.利用光源产生不同波长的一组光信号， 对产生的这组光信号 的部分或全部分别进行功率分支， 生成有一个或多个相同波长的两组光信 号， 即生成包含第一分支光信号的第一组光信号和包含第二分支光信号的 第二组光信号；
步骤 1 1 0.将所述两组光信号中的第一组光信号作为下行载波， 将下行 数据分别调制于所述第一组光信号； 将所述两组光信号中的第二组光信号 作为承载上行数据的上行载波；
步骤 200.将两组光信号分别进行波分复用， 形成分别包含所述第一组 光信号和所述第二组光信号的两路混合光信号；
步骤 31 0.将所述两路混合光信号进行交叉路由， 生成多个载波组信 号， 其中， 所述每个载波组信号包含两个不同波长的光信号， 每个载波组 信号包含的两个不同波长的光信号分别属于所述两路混合光信号；
步骤 320.每个载波组信号中波长不同的两个光信号分别作为同一光 网络单元的上行载波和下行载波。
本实施例将两组光信号分别作为上行载波和下行载波， 并将下行数据 调制到其中一组光信号中，接收到所述不同载波组信号的不同光网络单元， 分别将上行数据调制到载波组信号中的上行载波上， 通过接收的可逆路径 向上行发送。 对两组光信号分别进行波分复用具体可参见图 12、 1 3、 15、 1 6、 20等实施例。 本实施例对两组光信号进行交叉路由， 如图 5实施例所例 举的将两组光信号中第一组光信号的 和第二组光信号的 λ 2分别用作
0NU1 的下、 上行载波； 第一组光信号的 λ 2和第二组光信号的入3分别用作 0NU2的下、上行载波； ... ...； 而第一组光信号的 λ Ν和第二组光信号的入 分 别用作 0NUN的下、 上行载波， 这时， 每个载波组信号由波长相邻的两两光 波信号组成。 当然也可以釆取其它交叉路由或交叉联合的方式， 如将第一 组光信号的 和第二组光信号的入3分别用作 0冊1 的下、 上行载波； 第一 组光信号的 λ 2和第二组光信号的入4分别用作 0冊2的下、 上行载波； ... ...； 而第一组光信号的 λ Ν和第二组光信号的 λ 2分别用作 0NUN的下、 上行载波， 这时， 每个载波组信号由波长相隔的两两光波信号组成。 本领域普通技术 人员应当了解， 交叉路由的方式有多种， 只要是分别位于两组光信号中且不 同波长的光信号组合成一组即可， 以满足每个交叉组合信号作为同一 0NU的 上、 下行载波波长不同的要求。
图 7为本发明能够减少光源数量的光传输方法实施例四流程图。 图 7与 图 6不同， 如图 7所示， 本实施例包括：
步骤 1 00.利用光源产生不同波长的一组光信号， 对产生的这组光信号 的部分或全部分别进行功率分支后， 生成具有一个或多个相同波长的两组 光信号， 即生成包含第一分支光信号的第一组光信号和包含第二分支光信 号的第二组光信号；
步骤 1 1 0.将所述两组光信号中的第一组光信号作为下行载波， 将下行 数据分别调制于所述第一组光信号； 将所述两组光信号中的第二组光信号 作为承载上行数据的上行载波；
步骤 120.将调制有下行数据的信号和所述第二组光信号进行交叉耦 合， 生成多个载波组信号， 其中， 所述每个载波组信号耦合两个不同波长 的光信号；
步骤 21 0.对两组光信号交叉耦合后生成的多个载波组信号进行交叉 路由， 形成分别包含所述两组光信号中第一组光信号和第二组光信号的两 路混合光信号， 将所述两路混合光信号通过独立的光媒介进行传输；
步骤 220.将所述两路混合光信号进行交叉路由， 恢复成所述多个载波 组信号， 其中， 每一个载波组信号包含两个不同波长的光信号， 所述每一 个载波组信号包含的两个不同波长的光信号分别属于所述两路混合光信 号；
步骤 320.将交叉路由后的多个载波组信号作为不同光网络单元的载波。 对两组光信号进行交叉耦合之后再进行波分复用具体可参见图 1 4 或 图 1 8实施例中光线路终端内部的结构。
综合图 6和图 7实施例， 对两组光信号进行波分复用有多种方式：
1 ) 直接将第一组光信号和第二组光信号分别进行波分复用， 如， 将 第一组含有的 N个光信号作为一个波分复用器件 （如 AWG ) 的 N个输入进 行波分复用； 将第二组含有的 N个光信号作为另一个波分复用器件的 N个 输入进行波分复用， 由此形成波分复用后的两路混合光信号；
2 ) 第一组光信号和第二组光信号先进行交叉耦合， 生成载波组信 号， 每个载波组信号包括第一组光信号中的某一波长信号和第二组光信号 中的与该波长不同的一上行载波信号，如第一组光信号的 和第二组光信 号的 λ 3交叉耦合为第 1个载波组信号；第一组光信号的 λ 2和第二组光信号 的 λ 4交叉耦合为第 2个载波组信号； ... ...； 而第一组光信号的 第二组 光信号的 λ 2交叉耦合为第 Ν个载波组信号， 然后通过一个波分复用器件， 如通过一个 2 χ Ν端口 AWG器件对组合后的信号进行交叉路由， 输出波分复 用后的两路混合光信号， 具体可参见图 14所示的实施例。
本实施例在对两组光信号进行波分复用之前还加入了交叉耦合的步 骤， 用一个 2 χ Ν的耦合器件即可进行交叉耦合， 可以进一步减少波分复用 器件的数目， 降低成本。
上述实施例中， 利用多个光源产生的不同波长一组光信号， 生成有一 个或多个相同波长的两组光信号具体可以是： 设置 Ν个产生不同波长光信 号的光源， 每个光源产生的光信号功率分支为两路， 一分支作为承载下行 数据的下行载波， 另一分支作为承载上行数据的上行载波； 将所述 Ν个光 源产生的光信号通过光信号功率分支后的作为下行载波的 N个光信号下行 载波组成第一组光信号， 将所述 N个光源产生的光信号通过光信号功率分 支后作为上行载波的 N个光信号组成第二组光信号， 具体可参见图 1 0、 图 1 1、 图 12或图 14。 这时， 后续接收到所述波分复用后的两路混合光信号 的远端节点， 对两路混合光信号进行交叉路由， 组成载波组信号， 每组载 波组信号由分别属于所述两路混合光信号的两个光信号组成， 其中， 每组 载波组信号中的两个光信号的波长不同， 即只要分别属于两路混合光信号 且不同波长的光信号就可组合成一组， 波长可以两两相邻或两两相隔， 在此 不再赘述。
上述实施例中， 利用多个光源产生的具有不同波长的一组光信号， 生 成具有一个或多个相同波长的光信号的两组光信号具体还可以是：设置 N+1 个产生不同波长光信号的光源， 中间的 N-1 个光源中每个光源产生的光信 号功率分支为两路， 由此产生 2N-2路光信号； 将 N+1个光源中第一个光源 及中间 N-1个光源分支后的 N-1路光信号组成第一组光信号， 将 N+1个光源 中中间 N-1个光源分离出的 N-1路光信号及第 N+1个光源产生的光信号组成 第二组光信号， 具体可参见图 1 3。 这种分组的方式主要是考虑到实际设计 时， 远端节点进行交叉路由时， 如将第一组光信号的 λ Ν和第二组光信号的 入 交叉路由实现光波长组合输出时比较困难， 则加入了第 N+1个光源， 从 而可以将第 Ν个光源的承载下行有数据的信号与第 N+1 个光源的上行载波 信号组成第 Ν个载波组信号， 减少了设计的复杂度。
图 8为本发明能够减少光源数量的光传输方法实施例五流程图。 如图 8 所示， 本实施例包括：
步骤 1 000.将包含多个不同波长的一路混合光信号， 功率分支为与该 混合光信号波长相同的两路混合光信号；
步骤 2000.将所述两路混合光信号中不同波长的光信号进行交叉路由 后，组成由不同波长构成的载波组信号， 分别作为不同光网络单元的载波。 本实施例可参见图 16-18实施例的结构图进行理解，如图 16实施例远 端节点单元， 将一个包含不同波长的混合光信号 λ 2„、 X 3u λ ( N+1 ) u, 分成两路， 然后对两路光信号进行交叉路由， 形成若干个载波组信号， 将载波组信号作为不同光网络单元的上行载波， 本实施例对每个光网络单 元下发两个上行载波， 以获得较高的上行调制信号功率， 如果加上下行的 载波， 每个光网络单元将占用 3个载波信号。 对于现有技术， 如果每个光 网络单元占用 3个载波信号， 共有 N个光网络单元， 则共需 3N个光源， 釆 用本实施例所述的方法， 将一路混合光信号分成两路， 并通过交叉路由后 作为不同光网络单元的上行载波， 系统最少只需要 N个光源， 如图 18实施 例所示， 但最多不超过 2N个光源， 如图 17实施例所示。
图 9 为本发明能够减少光源数量的光传输方法实施例六流程图。 如图 9 所示， 本实施例包括：
步骤 1 1 00.将多路混合光信号中的至少一路混合光信号功率分支成两 路混合光信号； 所述多路混合光信号中的每路混合光信号均包含多个不同 的波长；
步骤 21 00.将多路混合光信号中未功率分支的剩余混合光信号与功率 分支后的两路或多路混合光信号进行交叉路由后， 组成由不同波长构成的 载波组信号， 分别作为不同光网络单元的载波。
本实施例与图 8实施例类似， 但图 8为一路混合光信号， 图 9为多路 混合光信号， 将其中一路混合光信号按照图 8的方法进行分离， 图 8是对 分离后的两路混合光信号进行交叉路由， 本实施例是将功分（功率分支） 后的混合光信号以及未功分的剩余光信号一起进行交叉路由， 具体可参见 图 1 9-20实施例中远端节点 （RN ) 单元内部的结构实施例， 所述的多路混 合光信号可以有相同的波长，如图 20实施例，有 2路混合光信号第一路混 合光信号的波长分别为 λ 2、 λ 3 λ ( Ν+1 ) , 第 2路混合光信号的波长 分别为 λ 1 λ 2 λ Ν, 图中的下标 " d"表示下行载波， "u "表示上 行载波， 由图 20可看出， 两路混合光信号共有 N-1 个波长相同。 如图 19 所示， 有 2路混合光信号第一路混合光信号的波长分别为 λ 1 λ 2 λ Ν, 第 2 路混合光信号的波长分别为 λ Ν+1 、 λ Ν+2 λ 2Ν, 图中的下 标 "d"表示下行载波， "u "表示上行载波， 由图 20可看出， 两路混合光 信号的波长各不相同， 不再详述。
图 10为本发明光线路终端实施例一结构示意图。 如图 10所示， 本实施 例包括产生不同波长的 N个光信号的光源模块 1 , 例如， 其中光源模块 1包 括 N个激光二极管 （La ser Di ode , 简称 LD ) , 用于产生 Ν个不同波长的光信 号， 分别表示为第一 LD、 第二 LD…第 N个 LD, 产生的 N个不同波长的光信号 记为 λ λ 2 λ Ν。 如图 10 中的接收模块 4，可以釆用光电二极管
( Photo Diode , 简称 PD )等接收不同波长的光信号， 不再举例。 另外， 由 于每一个光网络单元的载波组信号包含的下行载波和上行载波波长不同， 因此接收模块 4中接收到的某一 0冊发送的上行载波与发送给该 0冊的下行 载波的波长不同，从而实现波长重用又不影响上下行的。本实施例还包括： 处理模块 2 , 与光源模块 1连接， 用于利用光源模块 1产生的具有不同 波长的一组光信号， 将光源模块 1产生的这组光信号的部分或全部分别进 行功率分支，形成包含第一分支光信号的第一组光信号（此时第一组光信号 上还未调制数据）和包含第二分支光信号的第二组光信号，这两组光信号具 有一个或多个相同波长，如第一分支光信号和第二分支光信号的波长相同， 其中， 第一组光信号用作调制下行数据的下行载波， 第二组光信号用作上 行载波； 处理模块 2还包括调制功能， 将下行数据调制到第一组光信号中， 每一个光网络单元的下行数据调制到对应的一个波长。
波分复用模块 3 , 与处理模块 2连接， 用于对调制有下行数据的光信 号和所述第二组光信号分别进行波分复用， 形成分别包含调制有下行数据 的第一组光信号和用作上行载波的第二组光信号的两路混合光信号， 两路 混合光信号中包含的第一组光信号中调制有下行数据。 可以釆用现有的阵列波导光栅（ Arrayed Waveguide Grating,简称 AWG) 实现波分复用， 如图 10中利用第一 AWG和第二 AWG器件分别实现 Ι χΝ波 分复用 /解复用。
如图 10所示， 本实施例处理模块还可进一步细化， 包括：
分离子模块 23, 与光源模块 1连接， 用于将光源模块 1产生的具有不同 波长的一组光信号中部分或全部分别进行功率分支， 第一分支光信号作为 调制下行数据的下行载波提供给调制子模块 21, 第二分支的光信号作为上 行载波提供给上行载波子模块 22。 分离子模块 23可以是具有多个分立的分 支元件构成的虚拟模块也可以是具有多个分支元件的集成模块， 其中， 每一 个分支元件将一个光源产生的光信号进行功率分支， 生成两路波长相同的光 信号。
调制子模块 21, 与波分复用模块 3连接， 用于接收第一组光信号， 第一 组光信号包含分离子模块 23提供的第一分支光信号。 调制子模块 21将下行 数据调制于第一组光信号， 每一个光网络单元对应第一组光信号中的一个 载波。 为区别第一组光信号与第二组光信号， 将承载了下行数据的第一组光 信号加入下行（downstream, 简写 d)标志， 如图 10 所示， 第一组光信号为 λΜ、 λ1ά λΜ; 本实施例中釆用马赫曾德尔调制器（Mach-Zehnder
Modulator, 简称 MZM )作为调制器件； 调制子模块 21可以是多个分立的马 赫曾德尔调制器构成的虚拟模块， 也可以是包括多个马赫曾德尔调制器的 集成模块。
上行载波子模块 22, 与波分复用模块 3连接， 将产生的 N个不同波长的 第二组光信号作为上行载波； 如图 10 所示， 将上行载波信号加入上行
( upstream, 简写 u)标志, 第二组光信号记为 λ lu、 λ2υ、 、 λ Nu； 第 一组光信号与第二组光信号虽然加入了上行和下行的标志，但对于 λ lu、 λ 1(1表 示为同为波长 λ 的光，只是分别用于下行载波和上行载波，其它依次类推。
如果光源模块 1产生的光信号全部进行功率分支或者功率分支的光信 号的载波数目等于光网络单元的数目， 提供给调制子模块 21用作下行载波 的第一组光信号就是第一分支光信号； 如果光源模块 1 产生的光信号部分 进行功率分支或功率分支的光信号的载波数目小于光网络单元的数目， 提 供给调制子模块 21 用作下行载波的第一组光信号还要包括未分支的光信 号， 这个未分支的光信号可以由分离子模块 23提供，也可以直接由光源模 块 1提供。 同样的， 如果光源模块 1产生的光信号部分进行功率分支或者 功率分支的光信号的载波数目小于光网络单元的数目， 提供给上行载波子 模块 22用作下行载波的第一组光信号就是第一分支光信号； 如果光源模块
1 产生的光信号部分进行功率分支或功率分支的光信号的载波数目小于光 网络单元的数目， 提供给上行载波子模块 22用作上行载波的第二组光信号 还要包括未分支的光信号， 这个未分支的光信号可以由分离子模块 23 提 供， 也可以直接由光源模块 1提供。 本实施例重复利用产生的 N个光源， 将一组光源产生的不同波长的光信号分成了两组，一组用于承载下行数据， 另一组作为上行载波， 实现了将同一光源产生的同一波长光分别用于不同 光网络单元（0而）的上行和下行数据载波， 利用 N个光源产生的光可以作 为 N个不同的 0NU进行上、 下行数据的载波。 现有技术中有 N个 0冊的系 统需要使用 2N个光源， 本实施例只需设置 N个光源既可提供上、下行数据 的载波， 因此， 可以有效的减少网络中所使用的光源数量， 进而降低系统 成本， 与现有第二种技术方案相比， 本发明釆用较低的成本即可以实现减 少光源数量， 并且由于上下行载波的波长不相同， 所以信号传输的质量比 现有第一种技术方案相比又有很大提高。
图 11为本发明光线路终端实施例二结构示意图。本实施例与图 1 0类似， 相同的功能不再详述， 但不同之处在于， 本实施例中还包括： 交叉耦合模 块 105 , 与处理模块 102及波分复用模块 103连接， 用于将分别位于所述两 组光信号中且波长不同的两个光信号进行交叉耦合，生成多个载波组信号。
如图 1 1 中交叉耦合后的第一个载波组信号 λ Μ λ 2„, 第二个载波组信 号 λ Μ λ , …第 Ν个载波组信号 Nd lu , 本实施例波分复用模块 1 03 釆用 一个 2 χ Ν的 AWG器件即可， 具体可参见图 7实施例中的相关说明， 与图 1 0 实施例相比， 减少了一个 AWG器件， 更加节约了成本。
上述只是对 0LT 的几种例举， 本领域普通技术人员应当了解， 为适用不 同的需求， 与图 10-图 11不同， 光源产生模块提供的光源的数目 Μ可以设置 为 N+1或 Ν+2等， 如图 1 3中的光线路终端 （0LT ) 即为与图 1 0和图 11不同 的结构， 具体会在图 1 3实施例中进行阐述和说明。
图 12为本发明能够减少光源数量的光传输系统实施例一及远端节点单元 实施例一结构示意图。
本实施例远端节点单元 Β包括： 交叉路由模块， 与输入的 2路混合光信 号相连，用于对输入的 2路混合光信号进行交叉路由，生成多个载波组信号， 将多个载波组信号分别作为不同光网络单元的载波； 其中， 所述 2 路混合 光信号中的每路混合光信号均包含 Ν个不同波长的载波， 且两路混合光信 号具有一个或多个相同波长的载波， 其中一路混合光信号还调制有下行数 据。 交叉路由模块釆用如图 12所示的第三 AWG器件实现交叉路由功能。
本实施例提供了能够减少光源数量的光传输系统， 包括依次相连的光 线路终端 Α、 远端节点单元 Β及多个光网络单元 C , 光线路终端 Α参见图 10 实施例的说明， 结构与图 10类似， 光线路终端 A通过两个独立的光媒介将生 成的两路混合光信号与所述远端节点单元 B相连。
在光线路终端 （0LT ) , N个光源发出 N路光信号， 这里光源发出的光 信号为连续光， 将 N路光信号中部分或全部通过功率分支， 形成包含第一 分支光信号的第一组光信号形成包含第一分支光信号的第一组光信号和包 含第二分支光信号的第二组光信号， 并将下行数据调制到所述第一组光信 号调制有下行数据的光信号通过 0LT处的第一 AWG进行波分复用； 将第二 组光信号， 直接通过 0LT处的第二 AWG进行波分复用， 作为下发给光网络 单元的上行载波。 复用后的两路混合光信号分别由两根光纤传输， 一根传 输承载有下行数据的光信号， 另一根传输作为上行载波的光信号。 这里， 第一组光信号可以仅仅包括第一分支光信号 （光源数目 M等于光网络单元 数目 N或将光源产生的光信号的全部进行功率分支） ， 当然， 第一组光信 号可以既包括第一分支光信号又包括其它光信号 （光源数目 M大于光网络 单元数目 N或将光源产生的光信号的部分进行功率分支） 。 第二组光信号 可以仅仅包括第二分支光信号 （光源数目 M等于光网络单元数目 N或将光 源产生的光信号的全部进行功率分支） ， 当然， 第二组光信号可以既包括 第二分支光信号又包括其它光信号 （光源数目 M大于光网络单元数目 N或 将光源产生的光信号的部分进行功率分支） 。
在远端节点单元 B,两根光纤连接到一个 2 χΝ的第三 AWG器件，由于 AWG 器件的交叉路由特性，其 Ν个输出端口将分别输出一个下行数据信号和一个 上行载波的载波组信号。 如图 12所示， 第一输出端口输出 ( λ1(1, λ2υ) ， 第二输出端口输出 （ λΜ, 3u) , ......， 第 N个输出端口输出 （ λΜ, lu) 。 由于每个 AWG器件的自由光语范围 （Free Spectral Range , 简称 FSR)是 固定的， 因此， 只有满足一定工作波长关系才能实现波长的交叉路由， 输 出多个不同波长构成的载波组信号。 为了实现此交叉路由特性， 本实施例 需要合理地选择 N个光源的工作波长以及第三 AWG器件的 FSR。
远端节点单元 B输出的每个载波组信号对应多个光网络单元 （0而） C 中的某一光网络单元， 如， 输出端口 1对应第一光网络单元 1, …输出端 口 N对应第 N光网络单元。 每个光网络单元， 如第一光网络单元包括： 滤波模块， 与远端节点单元 B相连， 用于对接收到的载波组信号进行 滤波，分离出载波组信号中两个不同的波长，如图 12中第一光网络单元釆 用 TOM器件进行滤波， 需要说明的是， 本实施例含有滤波模块， 但用于其 他网络结构中时， 则不一定需要滤波， 此时就不需要滤波模块；
调制模块， 与滤波模块连接， 用于接收滤波后的上行载波信号， 调制 上行数据， 并经接收通道的可逆路径通过远端节点发送到光线路终端， 将 上行载波信号送至一个调制器件，如图 12所示的成本相对较低的电吸收调 制器 ( electro-absorption modulator, 简称 EAM ) , 调制上行数据。 调 制后的上行信号经可逆路径送至 0LT的接收（ Rx )模块；
下行接收模块， 与滤波模块连接， 用于接收承载有下行数据的下行载 波信号， 并进行探测获得下行数据，如图 12中将第一个载波组信号中的下 行数据信号送至第一光网络单元内部的接收模块。
本实施例提供了一种能够降低网络光源数量的光传输系统及远端节点 单元， 利用 N个不同波长的光源， 通过对光源信号的功率分支， 生成每组 有 N个不同波长的两组光信号， 并通过后续远端节点单元的交叉路由， 实 现了将同一光源产生的同一波长光信号分别用于不同光网络单元（ 0冊 )的 上行和下行载波， 利用一组光源即可以产生不同 0而的上、 下行载波。 与 现有技术方案 2相比， 本发明釆用较低的成本、 成熟的简单器件即可以实 现减少光源数量， 并且由于上下行载波的波长不相同， 所以接收的质量比 现有技术方案 1相比又有很大提高。
图 13为本发明能够减少光源数量的光传输系统实施例二、远端节点单元 实施例二及光线路终端实施例三结构示意图。 图 13与图 12实施例类似， 不 同之处在于光线路终端的内部结构， 本实施例中光线路终端 A1产生的两路 混合光信号也不具有完全相同的波长，远端节点单元 B输入的两路混合光信 号的波长不完全相同。 通过图 12实施例可看出， 图 12实施例远端节点单 元 B中的第三 AWG器件对输入光信号进行交叉路由时， 最后一个输出端口实 现 （ λΜ, lu) 的光波长组合输出对第三 AWG的设计实现比较困难， 本实 施例对于有 N个光网络单元的系统， 光线路终端 A1处釆用 （N+1 )个不同波 长的光源， 将该（N+1 )个不同波长的光源分为两组， 第一组光信号包括 λ ld、 λ2ά λΜ, 第二组光信号包括 λ2υ、 λ 3u λ (N+1)u, 在远端 节点 （RN) 单元 B1 进行交叉路由时， 输出端口 N输出 ( λΜ, λ (N+1)U) 给光 网络单元 CI 中的第 N光网络单元， λΜ和 λ ow)u分别作为第 N光网络单元的 下、 上行载波， 具体可参见方法实施例的相关说明， 不再赘述。 图 14为本发明能够减少光源数量的光传输系统实施例三结构示意图。 本 实施例中的光线路终端与图 1 1 实施例的结构类似。 本实施例系统与图 1 2 和图 1 3实施例不同， 本实施例光线路终端 A2 内部还釆用交叉耦合， 并利 用一个波分复用器件完成交叉耦合后两组光信号的波分复用， 具体可参见 方法实施例图 7及图 1 1中光线路终端的相关说明。
图 12-图 1 3实施例中的远端节点单元的波分器件只釆用一个 2 X N的 AWG 器件实现交叉路由， 但是， 本领域普通技术人员应当了解， 远端节点单元的 波分器件也可以才艮据图 10-图 11中 0LT内部相同的结构原理， 釆用两个 1 x N 的 AWG器件分别对两路混合光信号分别进行波分复用， 然后再将波分复用后 的信号进行交叉路由， 形成 N个载波组信号发送到各个 0NU, 具体可参见图 15。 图 15为本发明能够减少光源数量的光传输系统实施例四及远端节点单元 实施例三结构示意图。 其中远端节点单元 B2 的交叉路由模块与图 1 3的功能 相同， 但釆用不同的实现方式， 通过第三 AWG和第四 AWG器件分别波分复用 后再交叉形成多个载波组信号作为光网络单元 C1 的各个光网络单元的载波。
图 16为本发明能够减少光源数量的光传输系统实施例五及远端节点单元 实施例四结构示意图。 图 16实施例中远端节点单元与图 12-15不同， 本实 施例远端节点单元 B 3包括：
分离模块 B31 , 用于将包含 N个不同波长一路混合光信号， 功率分支成 与该混合光信号波长相同的两路混合光信号；
交叉路由模块 B 33 , 与分离模块 B31连接， 用于输入所述两路混合光 信号， 将将两路混合光信号进行交叉路由， 生成多个载波组信号， 将多个 载波组信号分别作为不同光网络单元的上行载波， 其中， 每个载波组信号 包含两个不同波长的光信号， 且每个载波组信号包含的两个不同波长的光 信号分别属于两路混合光信号。如图 16实施例中的第三 AWG器件， 实现交 叉路由功能， 对于下行信号， 只是釆用波分复用 （TOM )器件 B 32进行波分 复用后作为各个不同光网络单元的下行信号。
图 16实施例中利用 N+1 个光源实现对 N个光网络单元的载波， 如图 1 6所示，本实施例中多个光网络单元 C 3中的每个光网络单元均对应包含 3 个波长不同的载波组信号， 每个载波组信号包含一个上行载波和两个上行 载波， 光线路终端及光网络单元内部的结构前述实施例已经作了详细的阐 述， 在此不多作说明。 本实施例与现有技术相比， 减少了大约 2N个光源， 釆用成熟的器件即可完成， 成本低。
图 17为本发明能够减少光源数量的光传输系统实施例六结构示意图。 本 实施例远端节点单元内部结构与图 16类似， 光线路终端 A 3与图 12-图 1 6 实施例不同， 本实施例中光线路终端 A3釆用 2N个不同波长的光源， 一组 N个不同波长的光源产生的光信号作为下行载波， 另一组 N个不同波长的 光源产生的光信号作为上行载波， 如光源模块 A31中的第一 LD到第 N个 LD产生的 N个不同波长的一组波长光信号作为下行载波， 光源模块 A 32中 的第 N+1个 LD到第 2N个 LD产生的 N个不同波长的另一组波长光信号作为 上行载波， 经过远端节点单元 B4 中的分离模块进行功率分支后， 分成两 路上行载波混合光信号， 再进行后续的交叉路由， 实现生成不同光网络单 元的载波， 本实施例光线路终端没有做改进，但远端节点单元 B4由于进行 了功率分支和后续的交叉路由， 对于有 N个光网络单元的系统， 可以实现 利用 2N个光源产生 3N个载波信号， 与现有技术相比，也减少了 N个光源。 在本实施例中，Ν个光源产生的用作上行载波的光信号经过功率分支后为 Ν 个光网络单元提供 2Ν个上行载波， 和上面一样， 也可以是 N + 1 , 2N-1 个光源产生的用作上行载波的光信号为 Ν个光网络单元提供 2Ν个上行载波 图 18为本发明能够减少光源数量的光传输系统实施例七及远端节点单元 实施例五结构示意图。本实施例中光线路终端内部结构与图 14实施例相同， 远端节点单元与图 16类似， 整体结构与图 16实施例类似，但图 16需要使 用 N+1 个光源， 图 18 需要 Ν个光源， 本实施例中光线路终端 Α2 、 远端 节点单元 B5及光网络单元 C5内部的结构与前述实施例类似， 只是载波信 号的波长不同， 在此不多作说明。
图 19为本发明能够减少光源数量的光传输系统实施例八及远端节点单元 实施例六结构示意图。 本实施例中远端节点单元 B6 包括：
分离模块 B61 , 用于将两路混合光信号中的一路混合光信号（未调制下 行数据） 功率分支成与该混合光信号相同的两路混合光信号；
交叉路由模块 B62 , 与分离模块 B61连接， 用于将分离模块 B61输入的 功率分支后的两路混合光信号和未功率分支的光信号 （调制有下行数据） 这三路混合光信号进行交叉路由， 生成多个载波组信号， 将多个载波组信 号分别作为不同光网络单元的载波， 其中， 每个载波组信号包括三个不同 波长的光信号且每个载波组信号包含的三个不同波长的光信号分别属于输 入交叉路由模块 B62的三路混合光信号。
本实施例能够减少光源数量的光传输系统包括：
光线路终端 A3 , 用于通过两组光源产生两组光信号， 将两组光信号分 别进行波分复用， 形成分别包含所述两组光信号中第一组光信号和第二组 光信号的两路混合光信号， 其中， 所述两组光源具有各不相同的波长； 远端节点单元 B6 , 通过两个独立的光媒介与所述光线路终端连接， 用于 对输入的两路混合光信号进行交叉路由， 生成多个载波组信号， 将多个载波 组信号分别作为不同光网络单元的载波。
本实施例与图 1 7实施例的光线路终端及光网络单元相同，但是远端节 点单元与图 1 7实施例相比， 釆用一个 AWG器件作为交叉路由模块， 实现对 三路混合光信号交叉路由， 每个载波组信号包括三个载波， 分别发送给光 网络单元。本实施例中光线路终端产生的两路混合光信号的波长各不相同。
图 20为本发明能够减少光源数量的光传输系统实施例九及远端节点单元 实施例七结构示意图。 图 20实施例与图 1 9 实施例类似， 釆用一个 AWG器 件作为交叉路由模块， 但光线路终端与图 1 9 不同。 本实施例光线路终端 Al釆用与图 16实施例相同的结构， 光线路终端 A1产生的两路混合光信号 有 N-1个相同的波长， 本实施例与图 16实施例具有相同的光线路终端 A1 及光网络单元 C3 , 但远端节点单元 B7与图 19实施例类似。
本发明能有多种不同形式的具体实施方式，上面以图 4-图 20为例结合附 图对本发明的技术方案作举例说明， 这并不意味着本发明所应用的具体实例 只能局限在特定的流程图和实施例结构中， 本领域的普通技术人员应当了解， 上文所提供的具体实施方案只是多种优选用法中的一些示例， 任何将一组光 信号重复利用， 分为两组光信号， 每组光信号具有不同波长并且该两组光信 号有一个或多个相同波长， 并通过不同媒介分别传输， 并通过交叉路由实现 将两组光信号分别作为上、 下行载波信号， 的实施方式均应在本发明技术方 案所要求保护的范围之内。
本领域普通技术人员可以理解： 实现上述方法实施例的全部或部分步骤 可以通过程序指令相关的硬件来完成， 前述的程序可以存储于一计算机可读 取存储介质中， 该程序在执行时， 执行包括上述方法实施例的步骤； 而前述 的存储介质包括： R0M、 RAM, 磁碟或者光盘等各种可以存储程序代码的介质。
最后应说明的是： 以上实施例仅用以说明本发明的技术方案， 而非对其 限制； 尽管参照前述实施例对本发明进行了详细的说明， 本领域的普通技术 人员应当理解： 其依然可以对前述各实施例所记载的技术方案进行修改， 或 者对其中部分技术特征进行等同替换； 而这些修改或者替换， 并不使相应技 术方案的本质脱离本发明各实施例技术方案的精神和范围。

Claims

权 利 要 求
1. 一种光传输方法， 其特征在于， 利用光线路终端上的 M个光源为 N 个光网络单元提供 K个载波，所述 M、 N和 K都为大于 1的整数，且 K>M>=N , 所述方法包括：
将 M个光源产生的 M个不同波长的光信号的部分或全部分别进行功率 分支， 形成包含第一分支光信号的第一组光信号和包含第二分支光信号的 第二组光信号， 其中， 所述第一组光信号和所述第二组光信号均具有 N个 不同波长；
将所述第一组光信号和所述第二组光信号进行交叉路由， 形成需要提供 给 N个光网络单元的 N个载波组信号， 其中， 所述 N个载波组信号共有 K个 载波， 每一个载波组信号包含第一组光信号的载波和第二组光信号的载波， 且每个载波组信号包含的载波的波长不同。
2. 根据权利要求 1所述的方法， 其特征在于，
所述第一组光信号用作下行载波， 所述第二组光信号用作上行载波； 或者
所述第一组光信号和所述第二组光信号均用作上行载波。
3. 根据权利要求 2所述的方法， 其特征在于， 如果所述第一组光信号 用作下行载波， 所述第二组光信号用作上行载波； 所述方法还包括：
光线路终端将下行数据调制到第一组光信号；
则将所述第一组光信号和所述第二组光信号进行交叉路由， 形成需要提 供给 N个光网络单元的 N个载波组信号具体包括：
光线路终端将调制有下行数据的第一组光信号和所述第二组光信号进 行交叉耦合， 形成需要提供给 N个光网络单元的 N个载波组信号。
4. 根据权利要求 2所述的方法， 其特征在于， 如果所述第一组光信 号用作下行载波， 所述第二组光信号用作上行载波； 所述方法还包括： 光线路终端将下行数据调制到第一组光信号， 并将调制有下行数据的 第一组光信号和所述第二组光信号分别通过第一光媒介和第二光媒介发 送给光线路终端和光网络单元之间的远端节点单元；
则将所述第一组光信号和所述第二组光信号进行交叉路由， 形成需要提 供给 N个光网络单元的 N个载波组信号具体包括：
远端节点单元将来自第一光媒介的调制有下行数据的第一组光信号和来 自第二光媒介的第二组光信号进行交叉路由， 形成需要提供给 N个光网络单 元的 N个载波组信号。
5. 根据权利要求 4 所述的方法， 其特征在于， 每一个载波组信号包含 两个不同波长的上行载波， 则所述远端节点单元将来自第一光媒介的调制有 下行数据的第一组光信号和来自第二光媒介的第二组光信号进行交叉路由， 形成需要提供给 N个光网络单元的 N个载波组信号具体包括：
所述远端节点单元将来自第二光媒介的第二组光信号的部分或全部进行 功率分支， 形成与第二组光信号波长相同的第三组光信号和第四组光信号， 将所述第三组光信号、 第四组光信号和自第一光媒介的调制有下行数据的第 一组光信号进行交叉路由， 形成需要提供给 N个光网络单元的 N个载波组信 号， 每一个载波组信号具有第三组光信号的一个载波、 第四组光信号的一个 载波和所述来自第一光媒介的调制有下行数据的第一组光信号的一个载波； 或者
所述远端节点单元将来自第二光媒介的第二组光信号的部分或全部进行 功率分支， 形成与第二组光信号波长相同的第三组光信号和第四组光信号， 将第三组光信号和第四组光信号进行交叉路由， 形成 N个上行载波组信号， 将 N个上行载波组信号和自第一光媒介的调制有下行数据的第一组光信号的 N个下行载波信号进行交叉耦合， 形成需要提供给 N个光网络单元的 N个载 波组信号， 每一个载波组信号具有上行载波组信号的两个载波和所述自第一 光媒介的调制有下行数据的第一组光信号的一个载波。
6.—种光线路终端， 包括产生 M个不同波长的光源模块 （1 ) , 其特 征在于， 光线路终端上的 M个光源为 N个光网络单元提供 K个载波， 所述 Μ、 Ν和 Κ都为大于 1的整数， 且1 ^>= 所述光线路终端还包括：
处理模块（2 ) , 用于将光源模块 （ 1 ) 产生的具有不同波长的一组光 信号中部分或全部分别进行功率分支， 形成包含第一分支光信号的第一组 光信号和包含第二分支光信号的第二组光信号， 并将下行数据调制到所述 第一组光信号， 其中， 所述第一组光信号和所述第二组光信号均具有 Ν个 不同波长， 所述第二组光信号用作上行载波；
波分复用模块 （3 ) , 用于分别对调制有下行数据的光信号和所述第 二组光信号分别进行波分复用， 形成分别包含调制有下行数据的第一组光 信号和用作上行载波的第二组光信号的两路混合光信号；
接收模块 （4 )，用于接收 Ν个光网络单元的上行光信号， 其中， 每一 个光网络单元的上行光信号的载波与发送给该光网络单元的下行载波的 波长不同。
7.根据权利要求 6所述的光线路终端， 其特征在于， 所述处理模块（2 ) 包括：
分离子模块（23 ) , 用于将光源模块（1 )产生的具有不同波长的一组 光信号中部分或全部分别进行功率分支， 第一分支光信号作为调制下行数 据的下行载波提供给调制子模块（21 ) , 第二分支的光信号作为上行载波 提供给上行载波子模块（ 22 ) ；
调制子模块（21 ) , 用于接收第一组光信号， 将下行数据分别调制于第 一组光信号其中， 所述第一组光信号包含调制子模块（ 21 )提供的第一分支 光信号。
8.根据权利要求 6或 7所述的光线路终端， 其特征在于， 还包括： 交叉耦合模块（ 105 ) , 与处理模块（ 2 )及波分复用模块（ 3 )连接， 用 于分别从来自处理模块（ 2 )的两组光信号中选取波长不同的光信号进行交 叉耦合， 生成多个载波组信号。
9.一种远端节点单元， 其特征在于， 包括：
交叉路由模块， 用于对输入的多路混合光信号进行交叉路由， 组成多个 由不同波长构成的载波组信号， 将多个载波组信号分别作为不同光网络单 元的载波；
其中， 所述多路混合光信号中的每路混合光信号均包含多个不同波长 的载波， 且多路混合光信号具有一个或多个相同波长的载波。
10. 根据权利要求 9所述的远端节点单元， 其特征在于， 所述远端节点 单元还包括：
分离模块， 用于将包含多个不同波长的一路混合光信号， 功率分支成 波长相同的两路混合光信号， 将两路混合光信号发送给交叉路由模块； 交叉路由模块， 与分离模块连接， 用于输入所述两路混合光信号， 将 分别属于两路混合光信号中且波长不同的光信号进行交叉路由， 组成多个 由不同波长构成的载波组，将多个载波组分别作为不同光网络单元的载波。
11. 根据权利要求 9所述的远端节点单元， 其特征在于， 所述远端节点 单元还包括：
至少一个分离模块，每个分离模块用于将两路混合光信号中的第一路发 送给交叉路由模块， 将第二路混合光信号功率分支成与第二路混合光信号 波长相同的第三路混合光信号和第四路混合光信号， 并将所述第三路混合 光信号和第四路混合光信号发送给交叉路由模块， 其中， 所述第三路混合 光信号和第四路混合光信号中的每路混合光信号均包含多个不同的波长； 交叉路由模块， 与分离模块连接， 用于输入第一路混合光信号、 第二 路混合光信号和第三路混合光信号的三路混合光信号进行交叉路由， 组成 多个由不同波长构成的载波组信号， 将多个载波组信号分别作为不同光网 络单元的载波， 其中， 每一个载波组信号分别包含三路混合光信号中的一 个载波。
1 2.—种光传输系统， 其特征在于，包括依次相连的能够产生 M个不同波 长光信号的光线路终端、 远端节点单元及 N个光网络单元， 光线路终端能够 为所述 N个光网络单元提供 K个载波， 所述 M、 N和 K都为大于 1的整数， 且 K>M>=N ,
光线路终端， 用于产生 M个不同波长的一组光源， 对部分或全部光源 分别进行功率分支， 生成包含第一分支光信号的第一组光信号和包含第二 分支光信号的第二组光信号， 将下行数据调制于所述第一组光信号中， 将 调制有下行数据的第一组光信号和所述第二组光信号分别进行波分复用， 形成分别包含调制有下行数据的第一组光信号和第二组光信号的两路混 合光信号；
远端节点单元， 与所述光线路终端连接， 用于对输入的两路混合光信号 进行交叉路由， 组成多个由不同波长构成的载波组信号， 将多个载波组信 号分别作为不同光网络单元的载波， 其中， 每一个载波组信号包含两路混 合光信号中未调制下行数据的混合光信号的一个载波和两路混合光信号中 调制有下行数据的混合光信号的一个载波。
1 3.根据权利要求 1 2所述的光传输系统， 其特征在于， 所述远端节点 单元为一个 2 χ Ν 的阵列波导光栅器件， 用于将两路混合光信号进行交叉路 由， 生成 Ν个载波组信号， 将 Ν个载波组信号分别作为 Ν个光网络单元的 载波。
14.根据权利要求 1 2或 1 3所述的任一光传输系统， 其特征在于， 所 述远端节点单元包括：
分离模块， 用于将未调制下行数据的混合光信号， 功率分支成与该混 合光信号相同的两路混合光信号；
交叉路由模块， 与分离模块连接， 用于将分别属于所述功率分支后的 两路混合光信号且波长不同的光信号进行交叉路由， 生成多个载波组信 号， 将多个载波组信号分别作为不同光网络单元的上行载波；
波分复用模块， 用于将调制有下行数据的混合光信号进行波分复用， 生成多个分别作为不同光网络单元的下行载波。
1 5.根据权利要求 12或 1 3所述的任一光传输系统， 其特征在于， 所 述远端节点单元包括：
分离模块， 用于将两路混合光信号中未调制下行数据的一路混合光信 号， 功率分支成与该混合光信号波长相同的两路混合光信号；
交叉路由模块， 与分离模块连接， 用于输入功率分支后的两路混合光 信号及调制下行数据的一路混合光信号， 将分别位于三路混合光信号中且 波长不同的光信号进行交叉路由， 生成多个载波组信号， 将多个载波组信 号分别作为不同光网络单元的载波。
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