CN101902665B - Optical line terminal, optical add-drop multiplexer and optical access system - Google Patents
Optical line terminal, optical add-drop multiplexer and optical access system Download PDFInfo
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- CN101902665B CN101902665B CN200910203470.7A CN200910203470A CN101902665B CN 101902665 B CN101902665 B CN 101902665B CN 200910203470 A CN200910203470 A CN 200910203470A CN 101902665 B CN101902665 B CN 101902665B
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Abstract
The embodiment of the invention discloses an optical access system comprising one or more optical add-drop multiplexers sequentially connected through optical fibers in series to form a wavelength division multiplexing ring, wherein both ends of the wavelength division multiplexing ring are connected with one optical line terminal. The optical line terminal comprises a transmitter array, a multiplexer, a wavelength division ring protector, a receiver array and a demultiplexer, wherein the wavelength division ring protector is used for detecting whether the wavelength division multiplexing ring is broken or not; when the wavelength division multiplexing ring is normal, multiplexed downstream optical signals are transmitted to the wavelength division multiplexing ring from one end; when the wavelength division multiplexing ring is broken, the downstream optical signals are transmitted to the wavelength division multiplexing ring from both ends; and when the wavelength division multiplexing ring is normal, upstream optical signals are received from one end of the wavelength division multiplexing ring, and when the wavelength division multiplexing ring is broken, the upstream optical signals are received from both ends of the wavelength division multiplexing ring, and then the received upstream optical signals are transmitted to the demultiplexer.
Description
Technical field
The present invention relates to light access field, particularly a kind of optical line terminal, optical add/drop multiplexer and multi-plexing light accessing system.
Background technology
At light access field, the technique direction that has at present two kinds of main flows, a kind of is time division multiplexing EPON (Time Division Multiplexed Passive Optical Network, TDM-PON), another kind is Wave division multiplexing passive optical network (Wavelength Division Multiplexed Passive OpticalNetwork, WDM-PON); TDM-PON, WDM-PON respectively have advantage, and TDM-PON has: the good advantage such as low, the single copy broadcast of statistical multiplexing gain, very high peak rate, cost; WDM-PON has: bandwidth is huge, link load is little, fail safe and robustness is good, the advantages such as sensitivity height of continuous reception.
Along with the increase of user bandwidth demand and the continuous appearance of various emerging services, large user's capacity, large bandwidth, two-way speed symmetry, longer transmission range are the development trends of following Optical Access Network, and the scheme that merges TDM-PON and WDM-PON can meet following network demand.Thus, there is integrating the WDM+TDM mixing PON (WDM+TDM hybrid PON, HPON) of TDM-PON and WDM-PON advantage.
As shown in Figure 1, for a kind of HPON system, comprise: a plurality of time division multiplexing EPONs (TDM-PON) are by metropolitan area access point 101 (Metro Access Point, MAP) access wavelength division multiplexing ring (WDM) ring 102 (ring), network node (NN, Network Node) optical line terminal 103 (Optical Line Terminal, OLT), optical network unit 104 (Optical Network Terminal, ONT) can be also Optical Network Terminal (Optical Network Unit, ONU) here; Down direction at light signal, TDM-PON separates one from the light signal of the specific wavelength of OLT (103) by MAP (101) from WDM ring (102), then through one or more levels branch, arrive ONT (104), and recover downlink data by ONT (104); At up direction, uplink optical signal from the specific wavelength of ONT (104) is inserted in WDM ring (102) by MAP (101), above-mentioned light signal arrives the OLT (103) of network node (NN) through WDM ring (102), and recovers upstream data by OLT (103).Above-mentioned optical network unit 104 also can be described as Optical Network Terminal (ONT OpticalNetwork Terminal) sometimes.
Inventor finds that in realizing process of the present invention prior art exists following problem: in HPON, a network node (NN) with Optical Network Terminal (ONT) very many, if opening circuit appears in the trunk optical fiber of WDM ring, will cause large-scale network paralysis.
Summary of the invention
The technical problem that the embodiment of the present invention will solve is to provide a kind of optical line terminal, optical add/drop multiplexer and multi-plexing light accessing system, for realizing the backup protection of wavelength division multiplexing ring.
The embodiment of the present invention provides a kind of optical line terminal, comprising:
Transmitter array, multiplexer, wavelength-division ring protection device, receiver array, demodulation multiplexer;
Described transmitter array, for launching downlink optical signal;
Described multiplexer, multiplexing for described downlink optical signal is carried out, by the downlink optical signal after multiplexing, send to described wavelength-division ring protection device;
Whether described wavelength-division ring protection device, open circuit for detection of wavelength division multiplexing ring; When described wavelength division multiplexing ring is normal, described downlink optical signal after multiplexing is sent to described wavelength division multiplexing ring from one end; When described wavelength division multiplexing ring opens circuit, described downlink optical signal is sent to described wavelength division multiplexing ring from two ends; When described wavelength division multiplexing ring is normal, from one end of described wavelength division multiplexing ring, receive uplink optical signal, when described wavelength division multiplexing ring opens circuit, from the two ends of described wavelength division multiplexing ring, receive uplink optical signal, to described demodulation multiplexer, send the uplink optical signal receiving;
Described demodulation multiplexer, for the described uplink optical signal receiving is carried out to demultiplexing, sends to described receiver array by the uplink optical signal after demultiplexing;
Described receiver array, for according to the uplink optical signal after described demultiplexing, recovers upstream data.
The embodiment of the present invention provides a kind of optical add/drop multiplexer, and described optical add/drop multiplexer and optical fiber compose in series a wavelength division multiplexing ring, and the two ends of described wavelength division multiplexing ring are connected with an optical line terminal; Described optical add/drop multiplexer is connected with several network terminals by the tree type fiber optic tap net consisting of with branch optical fiber optical branching device; Described optical add/drop multiplexer comprises:
First wave division multiplexer, Second Wave division multiplexer; Wherein,
Described first wave division multiplexer, for receiving the downlink optical signal from optical line terminal from wavelength division multiplexing articulating, extracts the downlink optical signal of predetermined wavelength, sends the downlink optical signal of the predetermined wavelength of described extraction to described optical branching device; By the downlink optical signal of its commplementary wave length by the described Second Wave division multiplexer described wavelength division multiplexing ring that is again coupled back;
Described Second Wave division multiplexer, for accepting traveling optical signal from wavelength division multiplexing articulating, extracts the downlink optical signal of described predetermined wavelength, sends the downlink optical signal of the predetermined wavelength of described extraction to described optical branching device; By the downlink optical signal of its commplementary wave length by the described first wave division multiplexer described wavelength division multiplexing ring that is again coupled back;
Described optical branching device, for receive the downlink optical signal of described predetermined wavelength from first wave division multiplexer or Second Wave division multiplexer, is divided into after predetermined umber, to Optical Network Terminal, sends;
Described optical branching device, also for receiving the uplink optical signal from Optical Network Terminal, and sends described uplink optical signal to described first wave division multiplexer and Second Wave division multiplexer simultaneously;
Described first wave division multiplexer and Second Wave division multiplexer, also, for respectively the uplink optical signal that comes from described optical branching device being coupled into described wavelength division multiplexing ring, described wavelength division multiplexing ring sends to described optical line terminal by described uplink optical signal.
The embodiment of the present invention also provides a kind of multi-plexing light accessing system, comprising:
One or more optical add/drop multiplexers are connected in series successively by optical fiber, form wavelength division multiplexing ring, and the two ends of described wavelength division multiplexing ring are connected with an optical line terminal;
Described optical line terminal is connected with some Optical Network Terminal by described wavelength division multiplexing ring, sets up the communication link of bidirectional data interaction;
Wherein, described optical line terminal comprises: transmitter array, multiplexer, wavelength-division ring protection device, receiver array, demodulation multiplexer;
Described transmitter array, for launching downlink optical signal;
Described multiplexer, multiplexing for described downlink optical signal is carried out, by the downlink optical signal after multiplexing, send to described wavelength-division ring protection device;
Whether described wavelength-division ring protection device, open circuit for detection of described wavelength division multiplexing ring; When described wavelength division multiplexing ring is normal, described downlink optical signal is sent to described wavelength division multiplexing ring from one end; When described wavelength division multiplexing ring opens circuit, described downlink optical signal is sent to described wavelength division multiplexing ring from two ends; When described wavelength division multiplexing ring is normal, from one end of described wavelength division multiplexing ring, receive up optical information, when described wavelength division multiplexing ring opens circuit, from the two ends of described wavelength division multiplexing ring, receive uplink optical signal, to described demodulation multiplexer, send the uplink optical signal receiving;
Described demodulation multiplexer, for the uplink optical signal receiving is carried out to demultiplexing, and sends to described receiver array by the uplink optical signal after demultiplexing;
Described receiver array, for recovering upstream data according to the uplink optical signal after described demultiplexing.
By above embodiment; can find out; technical scheme of the present invention has following beneficial effect: after opening circuit appears in the trunk optical fiber of WDM ring; optical line terminal can send respectively downlink optical signal or receive uplink optical signal from the two ends of WDM ring; network still can be communicated by letter, and has realized the backup protection of WDM ring.
Accompanying drawing explanation
Fig. 1 is prior art HPON system schematic;
Fig. 2 is the embodiment of the present invention one optical line terminal structural representation;
Fig. 3 is the embodiment of the present invention one optical add-drop multiplexer architecture schematic diagram;
Fig. 4 is the embodiment of the present invention two HPON system configuration schematic diagrames;
Fig. 5 is the fiber cut status architecture schematic diagram of the embodiment of the present invention two HPON system WDM rings;
Fig. 6 is the structural representation of the embodiment of the present invention two OADM;
Fig. 7 is the embodiment of the present invention two optical network unit figure;
Fig. 8 is the embodiment of the present invention three HPON system configuration schematic diagrames;
Fig. 9 is the fiber cut status architecture schematic diagram of the embodiment of the present invention three HPON system WDM rings;
Figure 10 is the structural representation of the embodiment of the present invention three OADM;
Figure 11 is the embodiment of the present invention four HPON system configuration schematic diagrames;
Figure 12 is the fiber cut status architecture schematic diagram of the embodiment of the present invention four HPON system WDM rings;
Figure 13 is the embodiment of the present invention five HPON system configuration schematic diagrames.
Embodiment
The technical problem that the embodiment of the present invention will solve is to provide a kind of optical line terminal, optical add/drop multiplexer and multi-plexing light accessing system, can realize backup protection, in the multi-plexing light accessing system providing in the embodiment of the present invention: one or more optical add/drop multiplexers are connected in series successively by optical fiber, form wavelength division multiplexing ring, the two ends of described wavelength division multiplexing ring are connected with an optical line terminal; Described optical line terminal is connected with some Optical Network Terminal by described wavelength division multiplexing ring, sets up the communication link of bidirectional data interaction.Specifically refer to following description:
Embodiment mono-, and as shown in Figure 2, the embodiment of the present invention provides a kind of optical line terminal 200, comprising:
At the down direction of light signal, the propagation path of light signal is:
Whether wavelength-division ring protection device 203, open circuit for detection of wavelength division multiplexing ring 400; When wavelength division multiplexing ring 400 is normal, above-mentioned downlink optical signal is sent to wavelength division multiplexing ring 400 from one end; When wavelength division multiplexing ring 400 opens circuit, above-mentioned downlink optical signal is sent to wavelength division multiplexing ring 400 from two ends;
At the up direction of light signal, the propagation path of light signal is:
When wavelength division multiplexing ring 400 is normal, optical add/drop multiplexer 300 is one end transmission uplink optical signal to optical line terminal 200 by wavelength division multiplexing ring 400, when wavelength division multiplexing ring 400 opens circuit, optical add/drop multiplexer 300 is the two ends transmission uplink optical signal to optical line terminal 200 by wavelength division multiplexing ring 400;
Above-mentioned wavelength-division ring protection device 203, receives the uplink optical signal that above-mentioned optical add/drop multiplexer 300 sends, and uplink optical signal is sent to demodulation multiplexer 205;
Receiver array 204, for recovering upstream data according to the uplink optical signal after above-mentioned demultiplexing.
As shown in Figure 3, can be in the lump with reference to figure 2, the optical add/drop multiplexer 300 in technique scheme, specifically can comprise:
First wave division multiplexer 301, Second Wave division multiplexer 302;
At down direction, the propagation path of light signal is:
First wave division multiplexer 301, for receiving downlink optical signal, extracts the downlink optical signal of predetermined wavelength, and the downlink optical signal of its commplementary wave length is sent to Second Wave division multiplexer 302; To above-mentioned optical branching device 303, send the downlink optical signal of the predetermined wavelength of said extracted; To wavelength division multiplexing ring 400, send the downlink optical signal from its commplementary wave length of above-mentioned Second Wave division multiplexer 302, sending direction and first wave division multiplexer 301 receive the opposite direction of downlink optical signal from wavelength division multiplexing ring 400;
Second Wave division multiplexer 302, for receiving downlink optical signal, extracts the downlink optical signal of above-mentioned predetermined wavelength, and the downlink optical signal of its commplementary wave length is sent to first wave division multiplexer 301; To above-mentioned optical branching device 303, send the downlink optical signal of the predetermined wavelength of said extracted; To wavelength division multiplexing ring 400, send the downlink optical signal of its commplementary wave length sending from above-mentioned first wave division multiplexer 301, sending direction and Second Wave division multiplexer 302 receive the opposite direction of downlink optical signal from wavelength division multiplexing ring 400;
Optical branching device 303, is divided into predetermined umber by the descending light letter of predetermined wavelength, sends the downlink optical signal of the predetermined wavelength after above-mentioned minute to Optical Network Terminal;
At up direction, the propagation path of light signal is:
Above-mentioned optical branching device 303, also for receiving uplink optical signal, sends above-mentioned uplink optical signal to above-mentioned first wave division multiplexer 301 and Second Wave division multiplexer 302;
Above-mentioned first wave division multiplexer 301, also for sending above-mentioned uplink optical signal to wavelength division multiplexing ring 400, sending direction and first wave division multiplexer 301 receive the opposite direction of downlink optical signal from wavelength division multiplexing ring 400;
Above-mentioned Second Wave division multiplexer 302, also for sending above-mentioned uplink optical signal to wavelength division multiplexing ring 400, sending direction and Second Wave division multiplexer 302 receive the opposite direction of downlink optical signal from wavelength division multiplexing ring 400.
Above-described embodiment and embodiment mono-are accordingly, suppose when opening circuit does not appear in trunk optical fiber, optical add/drop multiplexer extracts downlink optical signal by first wave division multiplexer 301 from wavelength division multiplexing ring 400, and after opening circuit appears in trunk optical fiber, be subject to disconnected fibre to affect first wave division multiplexer 301 and cannot normally from wavelength division multiplexing ring 400, receive downlink optical signal.When opening circuit does not appear in trunk optical fiber, first wave division multiplexer 301 extracts the downlink optical signal of specific wavelength to optical branching device 303 from downlink optical signal, and the downlink optical signal of its commplementary wave length is sent to Second Wave division multiplexer 302, then continued to transmit toward next optical add/drop multiplexer from Second Wave division multiplexer 302 coupling echo division multiplexing rings 400.Relatively; when opening circuit appears in trunk optical fiber; optical line terminal can send respectively downlink optical signal from the two ends of wavelength division multiplexing ring 400; although at this moment above-mentioned optical add/drop multiplexer cannot receive downlink optical signal by first wave division multiplexer 301; but can receive downlink optical signal by Second Wave division multiplexer 302; thereby network still can communicate by letter, realized backup protection.Residing position can be referring to the residing position of optical add/drop multiplexer in Fig. 1 in system for optical add/drop multiplexer.
At follow-up embodiment bis-, to being implemented into five, will provide four kinds of multi-plexing light accessing systems, in multi-plexing light accessing system, by optical line terminal and the optical add/drop multiplexer used in above-described embodiment one, in subsequent embodiment, will be further described optical line terminal and optical add/drop multiplexer.As a signal, explanation no longer one by one in the figure of Optical Network Terminal 500 in subsequent embodiment; Optical Network Terminal 500 can have a plurality of, connects with an optical add/drop multiplexer (Optical Add-Drop Multiplexer, OADM); From OADM optical fiber, optical branching device, this three part of optical fiber down, belong to tree type branched network, each OADM can be connected with several optical network units by the tree-like branched network being comprised of with branch optical fiber optical branching device.
Embodiment bis-, the multi-plexing light accessing system that the present embodiment provides, in embodiments of the present invention, the position of each equipment in system do not need to make change, and residing position can the explanation no longer one by one in the position subsequent embodiment in system with reference to equipment in figure 1 in system for each equipment.As shown in Figure 4, be the schematic diagram of the WDM+TDM mixing PON system with backup protection.Whole system comprises and is positioned at central machine room (CentralOffice, CO) optical line terminal 1101 (Optical Line Terminal, OLT), outdoor optical add/drop multiplexer 1111 (Optical Add-Drop Multiplexer, OADM), WDM ring 1112.Wherein, optical line terminal 1101 comprises: reflector (Transmitter, TX) array 1102, receiver (Receiver, RX) array 1103, multiplexer 1104 (multiplexer, MUX)/demultiplexing 1105 (De-multiplexer, DEMUX), 2:2 splitter 1106,2:2 splitter 1107, optical switch 1108 (disconnect during normal condition; Interconnection when optical fiber opens circuit), isolator 1109, isolator 1110.The direction of arrow in Fig. 4 represents the direction that light signal can be propagated.
The light signal of take on optical add/drop multiplexer 1 (OADM1) at this for sake of convenience, is described the signal flow graph under the optical fiber normal condition of WDM ring 1112 as example;
At down direction, (λ 1 for the descending light being sent by TX array 1102, λ 2...... λ n) by MUX (1104), be multiplexed into a mixed light signal, and enter 2:2 splitter 1104, after 2:2 splitter 1104, there is 50% light signal to encircle 1112 by WDM and entered optical add/drop multiplexer 1111 (OpticalAdd-Drop Multiplexer, OADM), OADM1 (1111) extracts (drop) and goes out the downlink optical signal that wavelength is λ 1 from mixed light signal, then the downlink optical signal of λ 1 is divided into n part by the splitter of 2:n (SP), then enter n Optical Network Terminal (Optical Network Unit, ONU) recover downlink data.
At up direction, the uplink optical signal that is λ 1 from the wavelength of ONU is divided into n part after 2:n splitter, wherein two parts enter into OADM1 (1111), a clockwise direction in above-mentioned two parts is through OADM2, OAMD3 ... OAMDn, last again after the splitter 1107 of 2:2 in two, half enters DEMUX (1105), finally arrives RX1 (1103) and recovers upstream data (second half is by unidirectional isolator 1109 terminations); And another part of wavelength is to be divided into two halves after λ 1 uplink optical signal counter-clockwise direction transmission enters 2:2 splitter 1106, half enters TX array (1102) and is terminated after MUX (1104), and second half is terminated (because optical switch now disconnects) after entering optical switch 1108.The signal of other OADM node flows to identical with on OADM1, in this explanation no longer one by one.
Signal under the fiber cut state of WDM ring 1112 flows to, and as shown in Figure 5, " X " on the WDM ring 1112 in Fig. 5 is expressed as trip point, and in fact trip point can encircle at WDM 1112 optional position, in this embodiment of the present invention, is not construed as limiting; After the optical fiber of WDM ring 1112 opens circuit, optical switch 1108 closures.After optical switch 1108 closures, there is change in the flow direction of upward signal that is positioned at each OADM (1111) of the right one side of something of breakpoints of optical fiber, and the flow direction of downstream signal remains unchanged.Still the signal on optical add/drop multiplexer 1 of take flows to as example and is described; signal when not disconnected from optical fiber flows to different; wavelength is that the clockwise part uplink optical signal of λ 1 is terminated at breakpoints of optical fiber place; and the up light of counterclockwise part that wavelength is λ 1 enters another 2:2 splitter 1107 by optical switch 1108 again after 2:2 splitter 1106; pass through again DEMUX (1105) and enter RX1 (1103) and recover upstream data, thereby realized the protection of OADM1 (1111) uplink optical signal.And there is change than Fig. 4 in the flow direction of downstream signal that is positioned at each OADM (1111) of the left one side of something of breakpoints of optical fiber, because optical fiber disconnects, originally clockwise downlink optical signal cannot arrive OADM4～OADMn, but due to optical switch 1108 closures, downlink optical signal from MUX (1104) is divided into after two parts by 2:2 splitter (1106), some passes through 2:2 splitter 1107 after by optical switch 1108 again, and counter-clockwise direction enters OADMn～OADM4.Therefore,, after optical switch closure, solved the protection problem of the uplink and downlink signals of all OADM (1111) after optical fiber disconnects.
As shown in Figure 6, structural representation for OADM (1111), at down direction, down mixing light signal is (by wavelength X 1, the down mixing light signal that the light signal of λ 2...... λ n mixes) by fiber optic loop, entered along clockwise direction WDM1 (1301) the device arrival optical fiber 1302 of OADM, the downlink optical signal that WDM1 (1301) is λ 1 wavelength reflexes to optical fiber 1303, and remaining wavelength is that the light signal of λ 2...... λ n is transparent to optical fiber 1304.Wavelength is that λ 1 light signal is reflected to after optical fiber 1303, enter 2:n splitter (1305) and then enter n ONU, and the light signal that wavelength is λ 2...... λ n is transparent to after optical fiber 1304, clockwise direction passes through WDM2 (1306) (WDM1 and WDM2 can be just the same again, only need to adopt back-to-back to connect), then in optical fiber 1307 outputs, come back to wavelength division multiplexing ring, clockwise direction transmits toward next optical add/drop multiplexer.
At up direction, from the wavelength of n ONU, be that the uplink optical signal of λ 1 is after 2:n splitter (1305), have two parts output, a part is reflexed to optical fiber 1302 by optical fiber 1303 by WDM1 (1301), and counter-clockwise direction is transferred to the OLT of CO end; Another part is reflexed to optical fiber 1307 by optical fiber 1308 by WDM2 (1306), and clockwise direction sends back OLT.In the cut situation of optical fiber, downlink optical signal enters the optical fiber 1307 of WDM2 (1306) from counter-clockwise direction, now wavelength is that the light signal of λ 1 is reflected to optical fiber 1308, remaining light signal (wavelength is the light signal of λ 2...... λ n) is transparent to optical fiber 1304, thereby guarantees that OADM also can extract the light signal that wavelength is λ 1 from inhour enters the light signal of OADM.
As shown in Figure 7, provided the structural representation of the optical network unit 1400 being connected with OADM1 (1111), at down direction, wavelength is that the descending light of λ 1 is divided into two parts by 1:2 splitter 1401, a part is passed through optical detection diode 1402 (Photo Detector successively, PD), trans-impedance amplifier 1403 (transimpedance amplifier, TIA)/limiting amplifier (Limiting Amplifier, LA), protocol processor 1405 (protocol processor), recover downlink data, another part is reflected semiconductor optical amplifier 1407 (Semiconductor Optical Amplifier, RSOA) heavily use, at up direction, data are passed through protocol processor 1405, laser tube drive circuit 1406 (Laser Diode Driver successively, LDD), RSOA (1407) is carried in the light signal that wavelength is λ 1, wavelength is that the up light of λ 1 is sent to 2:n splitter 1305 through 1:2 splitter 1401.In up wavelength and the inconsistent situation of downstream wavelength, above-mentioned 1:2 splitter 1401 can adopt WDM to replace, for to downstream wavelength with upgoing wave progress row is multiplexing and demultiplexing, can reduce the lossy causing due to 1:2 splitter 1401, meanwhile, avoided reflection on descending and impact ascending performance.
Whether above-mentioned inspection wavelength division multiplexing ring opens circuit and can adopt optical switch controller to realize, and comprising:
Whether loss of signal alarm signal monitoring unit, received loss of signal alarm signal for monitoring;
Switch control unit, for after receiving loss of signal alarm signal, closed optical switch, otherwise, disconnect optical switch.
Or above-mentioned optical switch controller comprises:
Detect light transmitting element, for sending sensed light signal to wavelength division multiplexing environment-development;
Detect light receiving unit, for receiving sensed light signal;
Switch control unit, during for above-mentioned reception sensed light signal failure, closed optical switch, otherwise, disconnect optical switch.
Between the some Optical Network Terminal 500 that are connected with same tree type branched network, can share bandwidth resources by time division multiplexing mode;
In above-described embodiment, after opening circuit appears in the trunk optical fiber of WDM ring, optical line terminal can send respectively downlink optical signal from the two ends of WDM ring; Meanwhile, after opening circuit appears in the trunk optical fiber of WDM ring, optical line terminal receives respectively uplink optical signal from the two ends of WDM ring, so network can keep communicating by letter normally, has realized the backup protection of system.
Embodiment tri-, the multi-plexing light accessing system that the present embodiment provides, as shown in Figure 8 and Figure 9, schematic diagram for the WDM+TDM mixing PON system with backup protection, be with embodiment bis-differences, reflector (Transmitter in the present embodiment, TX) reflector in array 1502 and receiver (Receiver, RX) receiver in array 1503 is corresponding one by one, in a pair of receiver and reflector, the wavelength of receiver receiving optical signals is different from the wavelength that reflector sends light signal, the wavelength of optical signal that in embodiment bis-, receiver receives is identical with the wavelength of optical signal that reflector sends,
Whole multi-plexing light accessing system comprises and is positioned at central machine room (Central Office, CO) optical line terminal 1501 (Optical Line Terminal, OLT), outdoor optical add/drop multiplexer 1511 (Optical Add-DropMultiplexer, OADM), WDM ring 1512.Wherein, optical line terminal 1101 comprises: reflector (Transmitter, TX) array 1502, receiver (Receiver, RX) array 1503, multiplexer 1504 (multiplexer, MUX)/demultiplexing 1505 (de-multiplexer, DEMUX), 2:2 splitter 1506,2:2 splitter 1107, optical switch 1508 (disconnect during normal condition; Interconnection when optical fiber opens circuit), isolator 1509, isolator 1510.The direction of arrow in Fig. 8 represents the direction that light signal can be propagated.Concrete implementation is similar to embodiment bis-, and difference is, the WDM1 of OADM and the reflection of WDM2 (reflection) end respectively increase a port.Note: although the up wavelength of each optical add/drop multiplexer and the subscript of downstream wavelength are denoted as adjacent numeral in figure, this just for sake of convenience, it does not represent that actual optical wavelength must be also adjacent.
For sake of convenience, still take OADM1 is described as example.As shown in figure 10, at down direction, downlink optical signal (comprises wavelength X 1, the light signal of λ 2...... λ n) clockwise direction enters WDM1 (1703) the arrival optical fiber 1701 of OADM, its medium wavelength is that the light signal of λ 1 is reflected to optical fiber 1702, then passes through 4:N splitter (1704) and enter n ONU.If downlink optical signal is inhour to be entered WDM2 (1707) and then arrive optical fiber 1710, wavelength is that the light signal of λ 1 is reflected to optical fiber 1709, then passes through 4:N splitter (1706) and enter n ONU.
At up direction, wavelength is that the uplink optical signal of λ 2 is after 4:N splitter (1706), there are 4 part optical signals, wherein two parts are terminated at optical fiber 1702 and optical fiber 1709, other two parts are reflected to optical fiber 1701 and optical fiber 1710 by optical fiber 1704 and optical fiber 1708 respectively, then by counter-clockwise and clockwise direction, are sent back respectively the OLT of CO.Note, in order to realize the consistency of all ONU under each OADM, eliminate storage problem, can consider the up wavelength of each OADM and downstream wavelength to be configured to two different-wavebands.
In addition, in the present embodiment, the wavelength of the uplink optical signal of OADM and the wavelength of downlink optical signal can be also adjacent wavelength, like this can be in same port when the realizing of OADM defeated entry/exit (for example, in Figure 10, λ 1 and λ 2 are in the defeated entry/exit of same port), the splitter of available employing 2:N so in the present embodiment, thus the optical fiber between OADM and splitter saved.
In above-described embodiment, after opening circuit appears in the trunk optical fiber of WDM ring, optical line terminal sends respectively downlink optical signal from the two ends of WDM ring; Meanwhile, after opening circuit appears in the trunk optical fiber of WDM ring, optical line terminal receives respectively uplink optical signal from the two ends of WDM ring, so network can keep communicating by letter normally, has realized the backup protection of system.
Embodiment tetra-, and the multi-plexing light accessing system that the present embodiment provides is the schematic diagram of the WDM+TDM mixing PON system with backup protection, and distinctive points is CO end, as shown in Figure 11 and Figure 12, comprising:
Be positioned at central machine room (Central Office, CO) optical line terminal 1801 (Optical LineTerminal, OLT) comprising: reflector (Transmitter, TX) array 1802, receiver (Receiver, RX) array 1803, multiplexer 1804 (multiplexer, MUX)/demultiplexing 1805 (De-multiplexer, DEMUX), 1:2 splitter 1806,1:2 splitter 1807, optical switch 1808 (disconnect during normal condition; Intersection when optical fiber opens circuit), the direction of arrow in isolator 1809, isolator 1810, wavelength division multiplexer 1811, wavelength division multiplexer 1812, Figure 11 represents the direction that light signal can be propagated.
Be with embodiment bis-differences, after the 2:2 splitter that in the present embodiment, CO holds, uplink optical signal and downlink optical signal be respectively by two WDM1 (1811), WDM2 (1812) coupling, and (loss of WDM device is less than 2:2 splitter can to reduce like this loss of 3 dB that introduce due to 2:2 splitter.The splitter being connected with WDM1 (1811), WDM2 (1812) in addition can adopt 1:2 splitter, in this embodiment, and the realization of OADM and ONU is identical with embodiment bis-, no longer repeats.
Embodiment five, and the multi-plexing light accessing system that the present embodiment provides is the schematic diagram of the WDM+TDM mixing PON system with backup protection, and distinctive points is CO end, as shown in figure 13, comprising:
Be positioned at central machine room (Central Office, CO) optical line terminal 2001 (Optical LineTerminal, OLT) comprising: reflector (Transmitter, TX) array 2002, receiver (Receiver, RX) array 2003, multiplexer 2004 (multiplexer, MUX)/demodulation multiplexer 2005 (De-multiplexer, DEMUX), 1:2 splitter 2006,1:2 splitter 2007, switch 1 (2008), switch 2 (2009) (disconnect during normal condition; Intersection when optical fiber opens circuit), wavelength division multiplexer 2010, wavelength division multiplexer 2011.
The present embodiment is than embodiment tetra-, please also refer to Figure 11, distinctive points is, the present embodiment has removed isolator, directly adopt two switches (optical switch, OS): the backup protection that switch 1 (2008), switch 2 (2009) are realized while opening circuit; It should be noted that, there is an intersection at Figure 13 in above-mentioned switch 1 (2008), switch 2 (2009), is not a connection that light signal can be communicated by letter here.
Under normal operation, two switch OS1 (2008) in CO, OS2 (2009) disconnects, therefore, downlink optical signal from Tx1～Tx2n-1 enters fiber optic loop by WDM2 (2012) clockwise direction, and by WDM1 (2011), enters Rx2～Rx2n receiver from uplink optical signal clockwise direction in fiber optic loop of OADM1～OADMn.After optical fiber is cut off; OS1 (2008); OS2 (2009) closure; the downlink optical signal that enters clockwise WDM ring by WDM2 (2012) can arrive OADM4～OADMn; simultaneously; the counter-clockwise direction that the uplink optical signal of OADM1～OADM3 also can encircle by WDM is transferred to Rx2～Rx6, thereby realizes the protection of the uplink and downlink signals transmitting-receiving of each OADM
In above-described embodiment, after opening circuit appears in the trunk optical fiber of WDM ring, optical line terminal sends respectively downlink optical signal from the two ends of WDM ring; Meanwhile, after opening circuit appears in the trunk optical fiber of WDM ring, optical line terminal receives respectively uplink optical signal from the two ends of WDM ring, so network can keep communicating by letter normally, has realized the backup protection of system.
One of ordinary skill in the art will appreciate that all or part of step realizing in above-described embodiment method is to come the hardware that instruction is relevant to complete by program, described program can be stored in a kind of computer-readable recording medium, and the above-mentioned storage medium of mentioning can be in the storage medium of interior known any other form of memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field.
The optical line terminal above embodiment of the present invention being provided, optical add/drop multiplexer and multi-plexing light accessing system are described in detail, applied specific case herein principle of the present invention and execution mode are set forth, the explanation of above embodiment is just for helping to understand method of the present invention and core concept thereof; , for one of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention meanwhile.
Claims (10)
1. an optical line terminal, is characterized in that, comprising:
Transmitter array, multiplexer, wavelength-division ring protection device, receiver array, demodulation multiplexer;
Described transmitter array, for launching downlink optical signal;
Described multiplexer, multiplexing for described downlink optical signal is carried out, by the downlink optical signal after multiplexing, send to described wavelength-division ring protection device;
Whether described wavelength-division ring protection device, open circuit for detection of wavelength division multiplexing ring; When described wavelength division multiplexing ring is normal, described downlink optical signal after multiplexing is sent to described wavelength division multiplexing ring from one end; When described wavelength division multiplexing ring opens circuit, described downlink optical signal is sent to described wavelength division multiplexing ring from two ends; When described wavelength division multiplexing ring is normal, from one end of described wavelength division multiplexing ring, receive uplink optical signal, when described wavelength division multiplexing ring opens circuit, from the two ends of described wavelength division multiplexing ring, receive uplink optical signal, to described demodulation multiplexer, send the uplink optical signal receiving;
Described demodulation multiplexer, for the described uplink optical signal receiving is carried out to demultiplexing, sends to described receiver array by the uplink optical signal after demultiplexing;
Described receiver array, for according to the uplink optical signal after described demultiplexing, recovers upstream data.
2. optical line terminal according to claim 1, is characterized in that, described wavelength-division ring protection device comprises: the first optical switch, the second optical switch, the first splitter and the second splitter;
When opening circuit appears in described wavelength division multiplexing ring, closed described the first optical switch and the second optical switch; When described wavelength division multiplexing ring is normal, disconnect described the first optical switch and the second optical switch;
Described the first splitter, is divided into two parts for the downlink optical signal that described multiplexer is sent; A downlink optical signal is sent to described wavelength division multiplexing ring, another part of downlink optical signal sent to described the first optical switch;
Described the first optical switch is when closed, from the downlink optical signal of described the first splitter, by described the first optical switch, arrives the second splitter;
Described the second splitter, for sending to wavelength division multiplexing ring by the downlink optical signal that comes from described the first optical switch;
Described the first splitter, also for receiving uplink optical signal, and sends to described the second splitter by the uplink optical signal receiving through described the second optical switch;
When the second optical switch is closed, the uplink optical signal that comes from described wavelength division multiplexing ring can pass through described the second optical switch, and is that the first splitter is to the direction of the second splitter by direction;
Described the second splitter, also, for receiving uplink optical signal from described wavelength division multiplexing ring or described the second optical switch, sends to described demodulation multiplexer by described uplink optical signal.
3. optical line terminal according to claim 1, is characterized in that, described wavelength-division ring protection device comprises: the first isolator, the second isolator, the first optical switch, the second optical switch, the first splitter, the second splitter;
When opening circuit appears in described wavelength division multiplexing ring, closed described the first optical switch and the second optical switch; When described wavelength division multiplexing ring is normal, disconnect described the first optical switch and the second optical switch;
Wherein, described the first splitter, is divided into two parts for the downlink optical signal that described multiplexer is sent; A downlink optical signal is sent to wavelength division multiplexing ring, another part of downlink optical signal sent to the first optical switch;
The in the situation that of described the first optical switch closure, described the first isolator, for isolating all light signals from the second splitter toward the first splitter direction, only allows the downlink optical signal from the first splitter to the second splitter direction to pass through;
Described the second splitter, for sending to wavelength division multiplexing ring by the downlink optical signal that comes from described the first optical switch;
Described the first splitter, also for receiving uplink optical signal, and sends to described the second splitter by the uplink optical signal receiving through described the second optical switch and the second isolator;
The in the situation that of described the second optical switch closure, the second isolator is for isolating the light signal from the second splitter toward the first splitter direction, and only to allow direction be the first splitter passes through to the uplink optical signal of the direction of the second splitter;
Described the second splitter, also, for receiving uplink optical signal from described wavelength division multiplexing ring or described the second optical switch, sends to demodulation multiplexer by described uplink optical signal.
4. optical line terminal according to claim 1, is characterized in that, described wavelength-division ring protection device comprises: the first optical switch, the second optical switch, the first splitter, the second splitter, first wave division multiplexer, Second Wave division multiplexer;
When opening circuit appears in described wavelength division multiplexing ring, closed described the first optical switch and the second optical switch; When described wavelength division multiplexing ring is normal, disconnect described the first optical switch and the second optical switch;
Wherein, the first splitter, is divided into two parts for the downlink optical signal that described multiplexer is sent; A downlink optical signal is sent to wavelength division multiplexing ring by first wave division multiplexer, another part of downlink optical signal sent to the first optical switch;
The first optical switch is when closed, arrives Second Wave division multiplexer, and be coupled into wavelength division multiplexing ring by Second Wave division multiplexer from the downlink optical signal of described the first splitter by described the first optical switch;
Described first wave division multiplexer, also for receiving uplink optical signal, and out sends to described the second optical switch by the uplink optical signal demultiplexing receiving; When the second optical switch is closed, the uplink optical signal that comes from first wave division multiplexer can enter described the second splitter by described the second optical switch, and enters described demodulation multiplexer and receiver array by the second splitter;
Described Second Wave division multiplexer is also for going out uplink optical signal from described wavelength division multiplexing ring demultiplexing, and sends to described the second splitter, and described uplink optical signal is through demodulation multiplexer and receiver array described in the second splitter.
5. according to optical line terminal described in claim 1 to 4 any one, it is characterized in that,
The receiver of described receiver array is corresponding one by one with the reflector of described transmitter array; In a pair of receiver and reflector, the wavelength of receiver receiving optical signals is identical with the wavelength that reflector sends light signal, or has one-to-one relationship.
6. an optical add/drop multiplexer, described optical add/drop multiplexer and optical fiber compose in series a wavelength division multiplexing ring, and the two ends of described wavelength division multiplexing ring are connected with an optical line terminal; Described optical add/drop multiplexer is connected with several network terminals by the tree type fiber optic tap net consisting of with branch optical fiber optical branching device; It is characterized in that, described optical add/drop multiplexer comprises:
First wave division multiplexer, Second Wave division multiplexer; Wherein,
Described first wave division multiplexer, for receiving the downlink optical signal from optical line terminal from wavelength division multiplexing articulating, extracts the downlink optical signal of predetermined wavelength, sends the downlink optical signal of the predetermined wavelength of described extraction to described optical branching device; By the downlink optical signal of its commplementary wave length by the described Second Wave division multiplexer described wavelength division multiplexing ring that is again coupled back;
Described Second Wave division multiplexer, for accepting traveling optical signal from wavelength division multiplexing articulating, extracts the downlink optical signal of described predetermined wavelength, sends the downlink optical signal of the predetermined wavelength of described extraction to described optical branching device; By the downlink optical signal of its commplementary wave length by the described first wave division multiplexer described wavelength division multiplexing ring that is again coupled back;
Described optical branching device, for receive the downlink optical signal of described predetermined wavelength from first wave division multiplexer or Second Wave division multiplexer, is divided into after predetermined umber, to Optical Network Terminal, sends;
Described optical branching device, also for receiving the uplink optical signal from Optical Network Terminal, and sends described uplink optical signal to described first wave division multiplexer and Second Wave division multiplexer simultaneously;
Described first wave division multiplexer and Second Wave division multiplexer, also, for respectively the uplink optical signal that comes from described optical branching device being coupled into described wavelength division multiplexing ring, described wavelength division multiplexing ring sends to described optical line terminal by described uplink optical signal.
7. optical add/drop multiplexer according to claim 6, is characterized in that,
Described optical branching device is 2:N splitter or 4:N splitter.
8. a multi-plexing light accessing system, is characterized in that, comprising: one or more optical add/drop multiplexers, an optical line terminal; One or more optical add/drop multiplexers are connected in series successively by optical fiber, form wavelength division multiplexing ring, and the two ends of described wavelength division multiplexing ring are connected with an optical line terminal;
Described optical line terminal is connected with some Optical Network Terminal by described wavelength division multiplexing ring, sets up the communication link of bidirectional data interaction;
Wherein, described optical line terminal comprises: transmitter array, multiplexer, wavelength-division ring protection device, receiver array, demodulation multiplexer;
Described transmitter array, for launching downlink optical signal;
Described multiplexer, multiplexing for described downlink optical signal is carried out, by the downlink optical signal after multiplexing, send to described wavelength-division ring protection device;
Whether described wavelength-division ring protection device, open circuit for detection of described wavelength division multiplexing ring; When described wavelength division multiplexing ring is normal, described downlink optical signal is sent to described wavelength division multiplexing ring from one end; When described wavelength division multiplexing ring opens circuit, described downlink optical signal is sent to described wavelength division multiplexing ring from two ends; When described wavelength division multiplexing ring is normal, from one end of described wavelength division multiplexing ring, receive up optical information, when described wavelength division multiplexing ring opens circuit, from the two ends of described wavelength division multiplexing ring, receive uplink optical signal, to described demodulation multiplexer, send the uplink optical signal receiving;
Described demodulation multiplexer, for the uplink optical signal receiving is carried out to demultiplexing, and sends to described receiver array by the uplink optical signal after demultiplexing;
Described receiver array, for recovering upstream data according to the uplink optical signal after described demultiplexing;
Described optical add/drop multiplexer comprises: first wave division multiplexer, Second Wave division multiplexer;
Described first wave division multiplexer, for receiving the downlink optical signal from optical line terminal from wavelength division multiplexing articulating, extracts the downlink optical signal of predetermined wavelength, sends the downlink optical signal of the predetermined wavelength of described extraction to optical branching device; By the downlink optical signal of its commplementary wave length by the described Second Wave division multiplexer described wavelength division multiplexing ring that is again coupled back;
Described Second Wave division multiplexer, for accepting traveling optical signal from wavelength division multiplexing articulating, extracts the downlink optical signal of described predetermined wavelength, sends the downlink optical signal of the predetermined wavelength of described extraction to described optical branching device; By the downlink optical signal of its commplementary wave length by the described first wave division multiplexer described wavelength division multiplexing ring that is again coupled back.
9. multi-plexing light accessing system according to claim 8, is characterized in that, each optical add/drop multiplexer on described wavelength division multiplexing ring, and the tree type fiber optic tap net by consisting of optical branching device and several branch optical fibers, is connected with Optical Network Terminal;
Described optical branching device, for receive the downlink optical signal of described predetermined wavelength from first wave division multiplexer or Second Wave division multiplexer, is divided into after predetermined umber, to described Optical Network Terminal, sends;
Described optical branching device, also for receiving the uplink optical signal from described Optical Network Terminal, and sends described uplink optical signal to described first wave division multiplexer and Second Wave division multiplexer simultaneously;
Described first wave division multiplexer and Second Wave division multiplexer, also, for respectively the uplink optical signal that comes from described optical branching device being coupled into described wavelength division multiplexing ring, described wavelength division multiplexing ring sends to described optical line terminal by described uplink optical signal.
10. multi-plexing light accessing system according to claim 9, is characterized in that:
Described optical branching device is 2:N splitter or 4:N splitter.
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| CN102742199A (en) * | 2012-02-23 | 2012-10-17 | 华为海洋网络有限公司 | Optical add-drop multiplexer branch unit and control method thereof |
| US20160112136A1 (en) * | 2013-05-24 | 2016-04-21 | Telefonaktiebolaget Lm Ericsson (Publ) | Optical device, optical distribution network and respective methods performed thereby |
| CN103731227B (en) * | 2014-01-03 | 2016-06-29 | 桂林光隆光电科技股份有限公司 | A kind of Novel bidirectional optical add-drop multiplexer |
| CN105790839B (en) * | 2016-05-25 | 2018-03-20 | 烽火通信科技股份有限公司 | A kind of fibre system and method based on the unglazed relaying of wavelength-division multiplex |
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