Passive optical network based on wavelength-division multiplex technique
Technical field
The invention belongs to the passive optical network technique field, particularly based on the passive optical network of wavelength-division multiplex technique.
Background technology
EPON (PON) provides being connected of optical line terminal (OLT) and a plurality of optical network units (ONU), share OLT to the optical fiber medium between the distant-end node (RN), have cost low, be convenient to safeguard, to advantages such as miscellaneous service are transparent, while PON transition to optical fiber smoothly arrives family (FTTH), thereby has fine development prospect.
EPON is a power Splittable EPON, adopts star coupler along separate routes, on/descending transmission adopts the TDMA/TDM mode to realize the shared channel bandwidth, because the luminous power distribution, thereby limited ONU quantity, influence the further network capacity extension.
1 OLT can be installed on the every optical fiber of traditional EPON carry 32 tunnel user, although saving that can be more a large amount of than traditional transmission means fiber resource, but in the big city of the density of population, when doing access network construction, still need to lay a large amount of optical fiber as transmission medium, cause initial stage whole networking expense costliness.
The utility model content
The purpose of this utility model is to provide a kind of passive optical network based on wavelength-division multiplex technique, to solve the problem of the fiber resource deficiency in the existing EPON network, reduces network construction cost.
For reaching above-mentioned purpose, the utility model adopts following technical scheme:
A kind of passive optical network based on wavelength-division multiplex technique comprises:
A plurality of optical line terminals, described optical line terminal adopt separate up wavelength and downstream wavelength;
The Wavelength division multiplexer/demultiplexer that is connected with described a plurality of optical line terminal light, when downlink optical signal passed through described Wavelength division multiplexer/demultiplexer, it was used for that the downlink optical signal that a plurality of optical line terminals are exported is converged to optical fiber and transmits as multiplexer; When uplink optical signal when the described Wavelength division multiplexer/demultiplexer, it is as demodulation multiplexer, is used for uplink optical signal demultiplexing and export the described optical line terminal of corresponding wavelength to respectively;
Wavelength-division demultiplexing/the multiplexer that is connected with described Wavelength division multiplexer/demultiplexer optical fiber, when uplink optical signal passes through described Wavelength division multiplexer/demultiplexer, it is as multiplexer, being used for that the uplink optical signal that described a plurality of optical branching devices are exported is converged to optical fiber transmits, when downlink optical signal passes through this Wavelength division multiplexer/demultiplexer, it is as demodulation multiplexer, is used for downlink optical signal demultiplexing and export the optical branching device of corresponding wavelength to respectively;
With a plurality of optical branching devices that described wavelength-division demultiplexing/multiplexer light is connected, described optical branching device adopts up wavelength and the downstream wavelength identical with corresponding described optical line terminal; When downlink optical signal passes through described optical branching device, described optical branching device is used for energy distribution with the downlink optical signal of same wavelength to the described a plurality of optical network units that are connected with this optical branching device, when uplink optical signal passes through described optical branching device, it is used for receiving and converging this uplink optical signal, and sends it to described wavelength-division demultiplexing/multiplexer;
Be connected a plurality of optical network units with described optical branching device light, each optical network unit adopts two identical optical wavelength transmission uplink and downlink data of coupled optical branching device, described optical network unit receives the downlink optical signal of the described optical branching device transmission that is connected with its light, and sends uplink optical signal in turn to the described optical branching device that is connected with its light according to time-multiplexed mode.
As a kind of improvement of the present utility model, also comprise and be located at the image intensifer that connects on Wavelength division multiplexer/demultiplexer and the wavelength-division demultiplexing/multiplexer optical fiber.
As another improvement of the present utility model, also comprise two pump light sources that are used to image intensifer that bi-directional gain is provided.
As a kind of optimal way of the present utility model, described pump light source is ASE self-excitation radiating light source or super-radiance light emitting diode light source.
One improve as of the present utility model, described a plurality of optical line terminals, described Wavelength division multiplexer/demultiplexer and image intensifer are positioned at same core machine room again.
As another optimal way of the present utility model, described optical branching device is assigned to the optical network unit that is connected with this optical branching device with the energy of the downlink optical signal of same wavelength in average mode.
As an optimal way more of the present utility model, described optical branching device is fused biconical taper formula optical fiber splitter or planar optical waveguide splitter.
As an optimal way more of the present utility model, described Wavelength division multiplexer/demultiplexer and wavelength-division demultiplexing/multiplexer are film filter plate type device or array waveguide grating.
As an optimal way more of the present utility model, described optical line terminal is provided with the optical fiber interface that is used for being connected to metropolitan area network.
As an optimal way more of the present utility model, described optical line terminal be provided with 100,000,000 or gigabit Ethernet on connect mouth.
As an optimal way more of the present utility model, described optical branching device is the wavelength of same wave band with up wavelength and downstream wavelength that corresponding described optical line terminal adopts.
Of the present utility model having the following advantages:
1, utilizes wavelength-division multiplex technique, realize a plurality of optical line terminals and numerous optical network unit optical fiber communications, saved the fiber resource of the linkage section of metropolitan area network and sub-district, reduced the optical fiber cost of access of metropolitan area network by simple optical fiber.
2, the passive optical network that provides of the utility model based on wavelength-division multiplex technique, when the network bandwidth is upgraded, only need to increase the optical network line terminal quantity and the corresponding optical branching device of the use different wave length that inserts, just can realize transformation, greatly reduce the cost of transformation network bandwidth upgrading.
3, by wavelength-division multiplex technique, can be implemented in increases tens of times transmission bandwidth (relevant with multiplexing number of wavelengths) on the existing basis, and the user that can increase tens of times inserts quantity.
4, adopt two pump light sources to provide bi-directional gain for image intensifer 50, the two directional pump light source amplifies the up-downgoing light signal simultaneously, provides cost savings.
5, a plurality of optical line terminals, image intensifer unification can be positioned in the good core machine room of temperature conditions, increase the useful life of circuit, and reduce the Network Management cost.
Further specify the utility model below in conjunction with drawings and Examples.
Description of drawings
Fig. 1 is the existing passive optical network structure;
Fig. 2 is the passive optical network example structure schematic diagram of the utility model based on wavelength-division multiplex technique.
Embodiment
As shown in Figure 2, a kind of passive optical network based on wavelength-division multiplex technique comprises;
A plurality of optical line terminals 10, each optical line terminal all adopt separate up wavelength and downstream wavelength.Be optical line terminal 1,2 ..., n adopt respectively wavelength be λ 1, λ 2 ..., λ n light signal as uplink optical signal, and light network optical line terminal 1,2 ..., n adopt respectively wavelength be λ 1 ', λ 2 ' ..., λ n ' light signal as downlink optical signal.Described each optical line terminal both can be by being connected to metropolitan area network on the optical fiber interface, also can be by 100,000,000 or connected mode such as gigabit Ethernet mouth connect equipment such as core switch;
The Wavelength division multiplexer/demultiplexer 20 that is connected with described a plurality of optical line terminal light, when the downlink optical signal of a plurality of optical line terminal 10 outputs passes through this Wavelength division multiplexer/demultiplexer 20, it is as multiplexer, be used for optical line terminal 1,2 ..., n output wavelength be λ 1, λ 2 ..., λ n downlink optical signal converge in the optical fiber and transmit.When the uplink optical signal of wavelength-division demultiplexing/multiplexer 60 outputs passes through this Wavelength division multiplexer/demultiplexer 20, it is as demodulation multiplexer, be used for wavelength be λ 1 ', λ 2 ' ..., λ n ' uplink optical signal respectively demultiplexing and export to corresponding wavelength optical line terminal 1,2 ..., among the n;
Wavelength-division demultiplexing/the multiplexer 60 that is connected with described Wavelength division multiplexer/demultiplexer optical fiber, the effect of wavelength-division demultiplexing/multiplexer 60 is opposite with described Wavelength division multiplexer/demultiplexer 20, promptly when uplink optical signal passes through this Wavelength division multiplexer/demultiplexer 60, it is as multiplexer, be used for wavelength with n optical branching device output and be λ 1 ', λ 2 ' ..., λ n ' uplink optical signal converge in the optical fiber and transmit.When downlink optical signal when this Wavelength division multiplexer/demultiplexer 60, it is as demodulation multiplexer, be used for wavelength be λ 1, λ 2 ..., λ n downlink optical signal demultiplexing and exporting in n the optical branching device of corresponding wavelength respectively;
With a plurality of optical branching devices 70 that described wavelength-division demultiplexing/multiplexer light is connected, each optical branching device all adopts up wavelength and the downstream wavelength identical with corresponding optical line terminal.When the downlink optical signal of wavelength-division demultiplexing/multiplexer 60 outputs passes through this optical branching device 70, it is used for energy distribution with the downlink optical signal of same wavelength to the optical network unit that is connected with this optical branching device, to increase the quantity of the optical network unit (ONU) that can insert.The energy that preferably distributes the light signal of same wavelength in the present embodiment in average mode.When a plurality of optical network units 80 according to the uplink optical signal of time-division multiplex technology output during by this optical branching device 70, it is used for receiving and converging this uplink optical signal, and exports it to described wavelength-division demultiplexing/multiplexer 60.Described optical branching device 70 can be deposited in the user area, for example place such as building, user area.
Be connected a plurality of optical network units 80 with described optical branching device 70 light, described optical network unit 80 receives the downlink optical signal of described optical branching device 70 transmissions that are connected with its light, and sends uplink optical signal in turn to the described optical branching device 70 that is connected with its light according to time-multiplexed mode.Described optical network unit 80 adopts coupled optical branching device 70 two identical optical wavelength to transmit the uplink and downlink data.The transmission of wherein said uplink and downlink data can adopt time-multiplexed mode to carry out.Because this part can adopt time-multiplexed existing techniques in realizing in the optical-fiber network, therefore omit detailed description to this part;
And be located at and be used to strengthen the energy of up-downgoing light signal and the image intensifer 50 of increase transmission range on the optical fiber that connects Wavelength division multiplexer/demultiplexer and wavelength-division demultiplexing/multiplexer;
And be used to image intensifer 50 that two pump light sources 40,50 of bi-directional gain are provided, described pump light source 30,40 can adopt ASE (amplified spont-aneous emission, Amplification of Spontaneous Emission) self-excitation radiating light source also can use SLD (Super Luminescent Diode) super-radiance light emitting diode light source.
Wherein, described Wavelength division multiplexer/demultiplexer 20 and wavelength-division demultiplexing/multiplexer 60, can be film filter plate type (ThinFilm Filter Type WDM) device, also can be array waveguide grating (Array Waveguide Grating Type WDM, AGW).
Wherein, described optical branching device 70 can use fused biconical taper formula optical fiber splitter (Fused Fiber Splitter), also can use planar optical waveguide splitter (PLC Splitter).Each described optical branching device can connect 2~64 optical network units.
Described optical branching device 70 is the wavelength of same wave band with up wavelength and downstream wavelength that corresponding described optical line terminal 10 adopts.This wave band can be C-band wavelength (1530nm~1565nm), E+ wave band wavelength (1360nm~1460nm), also can use L-band (1570-1603nm) etc.