CN101702785B

CN101702785B - Multi-wavelength passive optical network system, wavelength reusing method and optical network unit

Info

Publication number: CN101702785B
Application number: CN200910236737.2A
Authority: CN
Inventors: 张民; 卢炼; 陈雪; 张治国
Original assignee: Beijing University of Posts and Telecommunications
Current assignee: Beijing University of Posts and Telecommunications
Priority date: 2009-10-29
Filing date: 2009-10-29
Publication date: 2013-01-23
Anticipated expiration: 2029-10-29
Also published as: CN101702785A

Abstract

The invention provides a multi-wavelength passive optical network system, a wavelength reusing method and an optical network unit. The system comprises a light line terminal, a wavelength division multiplex module and one or more optical network units; the light line terminal is used for transmitting multi-wavelength downlink signals and receiving uplink signals transmitted by the optical network units; each optical network unit comprises a first light branch module, a downlink signal receiving module and an uplink signal modulation module, wherein the first light branch module is used for splitting downlink signals with preset wavelength in the multi-wavelength downlink signals transmitted by the light line terminal into a first path and a second path; the downlink signal receiving module is used for receiving the first path of downlink signals; and the uplink signal modulation module is used for taking the second path of downlink signals as modulation light sources for radio-frequency uplink service signals of the optical network units, modulating the uplink signals of the optical network units and transmitting uplink radio-frequency optical signals obtained by modulation to the light line terminal. With the technical scheme, light signal sources of the whole system can be provided by only the light line terminal, thus light sources are not needed to be arranged at the optical network unit sides.

Description

The method of multi-wavelength passive optical network system, Wavelength reuse and optical network unit

Technical field

The present invention relates to the passive optical network technique field, particularly relate to method and the optical network unit of a kind of multi-wavelength passive optical network system, Wavelength reuse.

Background technology

At present, the line speed of broadband access network has reached G bps (Gbit/s) magnitude, and bandwidth demand and number of users are still in continuous growth.Traditional shared with time division multiplexing mechanism by a large number of users and be difficult to satisfy ever-increasing bandwidth demand owing to bandwidth based on time-multiplexed EPON (Time-DivisionMultiplexing Passive Optical Network, TDM-PON).In addition, the optical power budget that the TDM-PON system allows is limited, limited shunt ability and the effective coverage range of PON, namely the quantity of optical network unit (Optical Network Unit, ONU) and and optical line terminal (Optical Line TerminalOLT) between distance.By contrast, multi-wavelength passive optical network (Wavelength DivisionMultiplexing Passive Optical Network, WDM-PON) enlarge exponentially the network bandwidth by the multi-wavelength technology, have the advantages such as two-forty, easy upgrading, be considered to the desirable upgrade expanding solution of optical access network.

Access Network is very responsive to cost, so there are the outstanding problems such as cost height and wavelength configuration mechanism complexity in the WDM-PON scheme that has now proposed.For example, the WDM-PON scheme that has now proposed need to be the light source module of each ONU configuration respective wavelength.That is to say, in the enforcement of whole network system, be required to be a large amount of ONU configuration different wave length source modules.Like this, not only increase cost, also be unfavorable for extensive realization and maintenance that system disposes.In addition, for OLT, the wavelength of the whole network system of administration configuration causes network wavelength resource utilance low neatly, also is unfavorable for the optimization of network simultaneously.

Summary of the invention

The purpose of this invention is to provide a kind of multi-wavelength passive optical network system of Wavelength reuse, method and optical network unit of realization Wavelength reuse realized, in the multi-wavelength passive optical network structure that solves prior art, need to for the light source module of each ONU configuration respective wavelength, cause cost to increase and the low technical problem of network wavelength resource utilance.

To achieve these goals, the invention provides a kind of multi-wavelength passive optical network system, comprising: optical line terminal, Wavelength division multiplexing module and one or more optical network unit, it is characterized in that,

Described optical line terminal is used for sending the multi-wavelength downstream signal, and receives the up radio frequency light signal that described optical network unit sends;

Described Wavelength division multiplexing module, be connected with described each optical network unit with described optical line terminal, be used for the described multi-wavelength downstream signal that described optical line terminal sends is decomposed into each single wavelength downstream signal corresponding to each optical network unit, be sent to corresponding optical network unit, and after will closing ripple from the up radio frequency light signal of single wavelength of each optical network unit, be sent to described optical line terminal;

In the described optical network unit each comprises:

The first optical branch module is used for the multi-wavelength downstream signal of described optical line terminal transmission, the downstream signal of predetermined wavelength are divided into the first via and the second tunnel;

The downstream signal receiver module is used for receiving described first via downstream signal;

The upward signal modulation module, be used for the modulated light source of described the second road downstream signal as the radio frequency uplink service signal of optical network unit under the described upward signal modulation module, described radio frequency uplink service signal is modulated, and the up radio frequency light signal that modulation obtains is sent to described Wavelength division multiplexing module by described the first optical branch module, be sent to described optical line terminal by described Wavelength division multiplexing module.

Preferably, described multi-wavelength passive optical network system, wherein, described each optical network unit also comprises:

Electricity territory processing module, being used for obtaining two-way, to have a predetermined phase poor and carry the same frequency radio frequency uplink service signal of uplink business data: Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal;

Described upward signal modulation module, the downstream signal that is further used for described the second tunnel is divided into the five the road and the six the tunnel, downstream signal with the described the five road and the six tunnel is respectively as the modulated light source of described Third Road and the four road radio frequency uplink service signal, respectively described Third Road and the four road radio frequency uplink service signal are modulated, obtain two-way after the modulation and have the poor up radio frequency light signal of predetermined phase, the up radio frequency light signal that described two-way modulation is obtained is coupled, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal.

Preferably, described multi-wavelength passive optical network system, wherein, described upward signal modulation module comprises:

The second optical branch module, comprise the 3rd branch and the 4th branch, be used at down direction described the second road downstream signal being divided into the uniform the five the road and the six the tunnel, described the five road signal is by the transmission of described the 3rd branch, and described the six road signal is by the transmission of described the 4th branch;

The first reflection type semiconductor image intensifer, be connected with the 3rd branch and the described electric territory processing module of described the second optical branch module, be used for described Third Road radio frequency uplink service signal being modulated as modulated light source with the described the five tunnel downstream signal, and the first up radio frequency light signal that obtains is modulated in output;

The second reflection type semiconductor image intensifer, be connected with the 4th branch and the described circuit domain module of described the second optical branch module, be used for described the four road radio frequency uplink service signal being modulated as modulated light source with the described the six tunnel downstream signal, and the second up radio frequency light signal that obtains is modulated in output;

Described the second optical branch module is further used for the described first up radio frequency light signal and the second up radio frequency light signal are coupled, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal by described the first optical branch module.

Preferably, described multi-wavelength passive optical network system, wherein, described upward signal modulation module is: be aided with the waveguide type Michelson's interferometer of reflection type semiconductor image intensifer, described first, second reflection type semiconductor image intensifer lays respectively at up and down two arms of described waveguide type Michelson's interferometer.

Preferably, described multi-wavelength passive optical network system, wherein, when the uplink service signal of described optical network unit was base band uplink service signal, described electric territory processing module comprised:

Radio-frequency signal source is for generation of the radio-frequency carrier signal of two-way with the frequency homophase;

First-phase shifting formwork piece is connected with described radio-frequency signal source, is used for the phase difference of described two-way radio-frequency carrier signal is regulated, and obtains to have the first poor radio-frequency carrier signal of predetermined phase and the second radio-frequency carrier signal;

Modulation module, be used for described base band uplink service signal is divided into two-way, and described two-way base band uplink service signal is modulated to respectively on described the first radio-frequency carrier signal and the second radio-frequency carrier signal, obtain to carry described the 3rd radio frequency uplink service signal and the 4th radio frequency uplink service signal of described base band uplink service signal data.

Preferably, described multi-wavelength passive optical network system, wherein, the phase difference of described Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal is: 0 degree, 90 degree or 180 degree.

Preferably, described multi-wavelength passive optical network system, wherein, described upward signal modulation module also comprises:

Second-phase shifting formwork piece is arranged in the 3rd branch or the 4th branch of described the second optical branch module, is used for the phase difference of the described first up radio frequency light signal and the second up radio frequency light signal is adjusted to predetermined value.

Preferably, described multi-wavelength passive optical network system, wherein, when the uplink service signal of described optical network unit was radio frequency uplink service signal, described electric territory processing module comprised:

Third phase shifting formwork piece is used for the radio frequency uplink service signal that is divided into the two-way transmission is carried out phase adjusted, to obtain to have the poor described Third Road radio frequency uplink service signal of predetermined phase and the four road radio frequency uplink service signal.

Preferably, described multi-wavelength passive optical network system, wherein, each in the described optical network unit also comprises:

Optical signal isolator is connected with described downstream signal receiver module with described the first optical branch module, is used for straight-through described first via downstream signal to described downstream signal receiver module, and the light signal that stops described downstream signal receiver module to reflect.

Preferably, described multi-wavelength passive optical network system, wherein, the multi-wavelength downstream signal that described optical line terminal sending module sends is: the single wavelength downstream signal of multichannel is carried out the multi-wavelength downstream signal that forms behind the direct intensity modulation.

On the other hand, provide a kind of multi-wavelength passive optical network system to realize the method for Wavelength reuse, wherein, comprising:

Steps A, optical network unit is divided into the first via and the second tunnel with the downstream signal of the predetermined wavelength that optical line terminal sends;

Step B, optical network unit receives described first via downstream signal, and with described the second road downstream signal as the modulated light source that is used for modulated RF uplink service signal, after to described radio frequency uplink service signal modulation, obtain up radio frequency light signal, and described up radio frequency light signal is sent to described optical line terminal.

Preferably, described method, wherein, described step B comprises:

Step B1, obtaining two-way, to have a predetermined phase poor and carry the same frequency radio frequency uplink service signal of uplink service signal data: Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal;

Step B2, described the second road downstream signal is divided into the five the road and the six the tunnel, and with the described the five road and the six road downstream signal respectively as the modulated light source of described Third Road and the four road radio frequency uplink service signal, respectively described Third Road and the four road radio frequency uplink service signal are modulated, the two-way that obtains after the modulation has the poor up radio frequency light signal of predetermined phase, the described up radio frequency light signal that has after the poor two-way of predetermined phase is modulated is coupled, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal.

Preferably, described method, wherein, when the uplink service signal of described optical network unit was base band uplink service signal, described step B1 comprised:

Utilize radio-frequency signal source to produce two-way with the radio-frequency carrier signal of frequency homophase;

Utilize first-phase shifting formwork piece that the phase difference of described two-way radio-frequency carrier signal is regulated, obtain to have the first poor radio-frequency carrier signal of predetermined phase and the second radio-frequency carrier signal;

The described base band uplink service signal that optical network unit is sent is divided into two-way, described two-way base band uplink service signal is modulated to respectively on described the first radio-frequency carrier signal and the second radio-frequency carrier signal, obtains to carry described the 3rd radio frequency uplink service signal and the 4th radio frequency uplink service signal of described base band uplink service signal data.

Preferably, described method, wherein, when the uplink service signal of described optical network unit was radio frequency uplink service signal, described step B1 comprised:

Described radio frequency uplink service signal is divided into two-way;

Utilize third phase shifting formwork piece that the phase difference of described two-way radio frequency uplink service signal is regulated, obtain to have the poor described Third Road radio frequency uplink service signal of predetermined phase and the four road radio frequency uplink service signal.

Preferably, described method, wherein, described optical network unit is realized above-mentioned steps B by the upward signal modulation module, described upward signal modulation module comprises:

The second optical branch module comprises the 3rd branch and the 4th branch, is used for described the second road downstream signal is divided into the five the road and the six the tunnel, and described the five road signal is by the transmission of described the 3rd branch, and described the six road signal is by the transmission of described the 4th branch;

The first reflection type semiconductor image intensifer, be connected with the 3rd branch of described the second optical branch module, be used for described Third Road radio frequency uplink service signal being modulated as modulated light source with the described the five tunnel downstream signal, and the first up radio frequency light signal that obtains is modulated in output;

The second reflection type semiconductor image intensifer, be connected with the 4th branch of described the second optical branch module, be used for described the four road radio frequency uplink service signal being modulated as modulated light source with the described the six tunnel downstream signal, and the second up radio frequency light signal that obtains is modulated in output;

Described the second optical branch module is further used for the described first up radio frequency light signal and the second up radio frequency light signal are coupled, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal.

Another aspect provides a kind of optical network unit, wherein, comprising:

The first optical branch module is used for the multi-wavelength downstream signal of optical line terminal transmission, the downstream signal of predetermined wavelength are divided into the first via and the second tunnel;

The upward signal modulation module, be used for the modulated light source of described the second road downstream signal as the radio frequency uplink service signal of optical network unit under the described upward signal modulation module, described radio frequency uplink service signal is modulated, and the up radio frequency light signal that modulation obtains is sent to described optical line terminal.

Preferably, described optical network unit wherein, also comprises:

Described upward signal modulation module, the downstream signal that is further used for described the second tunnel is divided into the five the road and the six the tunnel, downstream signal with the described the five road and the six tunnel is respectively as the modulated light source of described Third Road and the four road radio frequency uplink service signal, respectively described Third Road and the four road radio frequency uplink service signal are modulated, acquisition has the up radio frequency light signal after the poor two-way modulation of predetermined phase, the described up radio frequency light signal that has after the poor two-way of predetermined phase is modulated is coupled, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal.

Preferably, described optical network unit, wherein, described upward signal modulation module comprises:

Preferably, described optical network unit, wherein, described upward signal modulation module is: be aided with the waveguide type Michelson's interferometer of reflection type semiconductor image intensifer, described first, second reflection type semiconductor image intensifer lays respectively at up and down two arms of described waveguide type Michelson's interferometer.

Preferably, described optical network unit, wherein, when the uplink service signal of described optical network unit was base band uplink service signal, described electric territory processing module comprised:

Modulation module, be used for described base band uplink service signal is divided into two-way, and described two-way base band upward signal is modulated to respectively on described the first radio-frequency carrier signal and the second radio-frequency carrier signal, obtain to carry described Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal of described base band uplink service signal data.

Preferably, described optical network unit, wherein, the phase difference of described Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal is: 0 degree, 90 degree or 180 degree.

A technical scheme in the technique scheme has following technique effect:

By adopt the upward signal modulation module at the optical network unit ONU place, can realize only being provided by optical line terminal OLT the optical signal source of whole system, utilize downlink optical signal as the modulated light source of ONU side radio frequency uplink service signal, reuse and load upward signal at downlink optical signal during through the ONU side, send back to again OLT, like this, the ONU side is utilized the wavelength of OLT assignment, does not need to configure light source module again, thereby provides cost savings, and realized colourlessization of ONU, namely ONU has had the wavelength adaptivity;

Further, owing to downgoing baseband signal and the up radio frequency light signal with certain frequency displacement stagger at frequency domain, thus can carry out the single fiber bi-directional transmission, thus really realize the full duplex work of whole multi-wavelength passive optical network.

Description of drawings

Fig. 1 is the structural representation of the multi-wavelength passive optical network system of one embodiment of the invention;

Fig. 2 is the structural representation of the multi-wavelength passive optical network system of another embodiment of the present invention;

Fig. 3 is the structural representation of the multi-wavelength passive optical network system of further embodiment of this invention;

Fig. 4 is the structural representation of the optical network unit of the embodiment of the invention;

Fig. 5 is the structural representation of the multi-wavelength passive optical network system of further embodiment of this invention;

Fig. 6 is that the upward signal of radio frequency 5GHz is through the spectrogram of RSOA-MI structure output among the present invention embodiment shown in Figure 4;

Fig. 7 is that the upward signal of radio frequency 32GHz is through the spectrogram of RSOA-MI structure output among the present invention embodiment shown in Figure 4;

Fig. 8 is in the embodiment of the invention, the structural representation of a plurality of passive optical network PON module-cascades of optical line terminal;

Fig. 9 is the schematic flow sheet that the multi-wavelength passive optical network system of the embodiment of the invention is realized the method for Wavelength reuse.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, describe the present invention below in conjunction with the accompanying drawings and the specific embodiments.

Fig. 1 is the structural representation of the multi-wavelength passive optical network system of one embodiment of the invention.Such as Fig. 1, the multi-wavelength passive optical network system of the embodiment of the invention comprises: optical line terminal 101, Wavelength division multiplexing module 102 and one or more optical network unit 103, wherein,

In the described optical network unit each comprises: the first optical branch module 104 is used for the multi-wavelength downstream signal of described optical line terminal transmission, the downstream signal of predetermined wavelength are divided into the first via and the second tunnel; Downstream signal receiver module 105 is used for receiving described first via downstream signal, and obtains the downstream signal data in the described downstream signal, obtains the target data that OLT sends to the user; Upward signal modulation module 106, be used for the modulated light source of described the second road downstream signal as the radio frequency uplink service signal of optical network unit under the described upward signal modulation module, described radio frequency uplink service signal is modulated, and the up radio frequency light signal that modulation obtains is sent to Wavelength division multiplexing module by the first optical branch module, be sent to optical line terminal by Wavelength division multiplexing module again.

This technical scheme of the embodiment of the invention is by adopting the upward signal modulation module at the optical network unit ONU place, can realize only being provided by optical line terminal OLT the optical signal source of whole system, utilize downlink optical signal as the modulated light source of ONU side radio frequency uplink service signal, reuse and load the uplink service signal during through the ONU side at downlink optical signal, send back to again OLT, like this, by OLT assignment wavelength, the ONU side does not just need to configure light source module again, thereby realized colourlessization of ONU, namely ONU has had the wavelength adaptivity.

In an embodiment of the present invention, concrete corresponding which wavelength of which optical network unit can be by in advance assignment of OLT.

Preferably, in the described multi-wavelength passive optical network system, described each optical network unit also comprises: electric territory processing module, and be used for obtaining two-way, to have a predetermined phase poor and carry the same frequency radio frequency uplink service signal of uplink business data: Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal; Described upward signal modulation module, the downstream signal that is further used for described the second tunnel is divided into the five the road and the six the tunnel, downstream signal with the described the five road and the six tunnel is respectively as the modulated light source of described Third Road and the four road radio frequency uplink service signal, respectively described Third Road and the four road radio frequency uplink service signal are modulated, obtain that the two-way modulation obtains, have a poor up radio frequency light signal of predetermined phase, the up radio frequency light signal that described two-way modulation is obtained is coupled, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal.

Preferably, described multi-wavelength passive optical network system, wherein, described upward signal modulation module comprises: the second optical branch module, comprise the 3rd branch and the 4th branch, be used at down direction described the second road downstream signal being divided into the uniform the five the road and the six the tunnel, described the five road signal is by the transmission of described the 3rd branch, and described the six road signal is by the transmission of described the 4th branch; The first reflection type semiconductor image intensifer (RSOA, Reflective Semiconductor Optical Amplifier), be connected with the 3rd branch and the described electric territory processing module of described the second optical branch module, be used for described Third Road radio frequency uplink service signal being modulated as modulated light source with the described the five tunnel downstream signal, and the first up radiofrequency signal that obtains is modulated in output; The second reflection type semiconductor image intensifer, be connected with the 4th branch and the described circuit domain module of described the second optical branch module, be used for described the four road radio frequency uplink service signal being modulated as modulated light source with the described the six tunnel downstream signal, and the second up radio frequency light signal that obtains is modulated in output; Described the second optical branch module is further used for the described first up radio frequency light signal and the second up radio frequency light signal are coupled, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal by described the first optical branch module.

Fig. 2 is the structural representation of the multi-wavelength passive optical network system of another embodiment of the present invention.Such as Fig. 2, the multi-wavelength passive optical network system of this embodiment of the invention comprises: an optical line terminal OLT 201, a waveguide array grating 202 and n optical network unit ONU 203, n is integer.Exemplarily, the number n of ONU can be 16,32,64 etc. usually.Such as Fig. 2, OLT is with λ ₁To λ _nThe downstream signal of n wavelength send to respectively among n the ONU.

Among this embodiment, the optical signal source of whole system is provided by OLT, adopting the modulating part of the upward signal that comprises RSOA at the ONU place is the upward signal modulation module, replace light source with the RSOA module as modulator, downlink optical signal is reflected and reuses and load the up radio frequency light signal of radio frequency upward signal radio frequency uplink service signal formation when the ONU side, send back to again OLT, thereby ONU has colourless property, namely have the wavelength adaptivity.Downstream signal is baseband signal, and by adjusting the first front up radio frequency light signal of coupling and the phase difference of the second up radio frequency light signal, can realize having the upward signal of the particular modulation forms such as radio frequency single-side belt SSB, double-side band DSB or inhibition light carrier OCS, thereby when realizing full duplex, can effectively suppress the unfavorable factors such as reverse Rayleigh scattering and optical fiber dispersion.

In this example, Wavelength division multiplexing module is wavelength division multiplexer, and wavelength division multiplexer is called again the WDM multiplexing demultiplexing device, can utilize the device realizations such as array waveguide grating AWG, adopt the port organization of 1 * n, wherein n is integer, exemplarily, n is 16,32 or 64 etc., and its value equates with the quantity of ONU.Wavelength division multiplexer is decomposed into each single wavelength signals corresponding to each ONU with descending multiple wavelength optical signal, and will be multiplexed with one the tunnel corresponding to the up radio frequency light signal of the multi-wavelength of OLT from the up radio frequency light signal of single wavelength of each ONU.

Fig. 3 is the structural representation of the multi-wavelength passive optical network system of further embodiment of this invention.Fig. 4 is the structural representation of the optical network unit of the embodiment of the invention.Such as Fig. 3, among this embodiment, optical line terminal 6 comprises at least one optical line terminal transmitter module TX1 61 and optical line terminal receiver module RX163; Wherein, optical line terminal transmitter module 61 be used for downstream signal is carried out the direct modulation of laser, thereby the downstream signal that the optical line terminal transmitter module sends is baseband signal; Optical line terminal receiver module 63 be used for to receive upward signal, in the technical scheme of the present invention, is used for receiving the up radiofrequency signal that Optical Network Terminal sends, the processing that up radiofrequency signal is carried out demodulation and is scheduled to.

In this example, in the optical line terminal 6, downstream signal obtains by direct modulated laser in TX1 61, carries out downlink transfer through circulator 62 injection fibres 5.And from optical network unit, and the upward signal that passes through optical fiber 5 outputs enters RX1 63 behind circulator 62.

Distant-end node 4 is mainly wavelength division multiplexer, can utilize the device realizations such as existing array waveguide grating AWG.Be mainly used at up direction the upward signal from each ONU being carried out the multiplexing road of namely closing, and at down direction the downstream signal from OLT carried out shunt.

Such as Fig. 3 and Fig. 4, optical network unit 1 comprises: the receiving unit 2 of 1 * 2 optical branching device 3, downstream signal and the modulating part 1 of upward signal.Among this embodiment, the modulating part 1 of upward signal comprises: the waveguide type Michelson's interferometer RSOA-MI that is aided with reflection type semiconductor image intensifer RSOA.In this example, RSOA-MI comprises: 1 * 2 optical branching device 3 and two RSOA15,16.

Such as Fig. 3, arrow represents the transmission direction of signal, and what thick line was described is light path, and what fine rule was described is the transmission channel of electric territory signal.The downlink transfer light signal is all with " d ^*" represent in turn by the light down direction, the uplink light signal is all with " u ^*" represent in turn by the light up direction.Such as Fig. 3, particularly, downstream signal comprises that " d1 " is to " d5 "; Upward signal comprises that " u1 " is to " u5 ".

The below realizes that to the multi-wavelength passive optical network system of this embodiment the process of Wavelength reuse describes:

At down direction:

1 * 2 optical branching device 3, with preassigned, be divided into 1: 1 two-way with single wavelength downlink optical signal d1 corresponding to optical network unit under self: one road d2 enters the receiving unit 2 of downstream signal, via optical signal isolator 21, enter the downstream signal receiver module 22 of ONU; Another road d3 enters the modulating part 1 of upward signal.In the modulating part 1 of upward signal, by 1 * 2 optical branching device 18 the light signal d3 that enters is divided into uniform two bundle d4, d5, enter respectively RSOA-MI up and down among the RSOA 15 and RSOA 16 of two arms, RSOA because of have gain fast saturated and slow recovery characteristics the light signal of input had amplitude clamp down on effect, the optical signal magnitude after being reflected by RSOA changes little and then as the modulated light source of uplink service signal.Exemplarily, this optical branching device 18 is the Waveguide type optical branching device.

In the embodiments of the invention, uplink business data can be divided into two kinds of situations, uplink business data can have following two kinds of situations: when the uplink service signal of (1) optical network unit is base band uplink service signal, base band uplink service signal is modulated to radio frequency through the electric territory of ONU processing module first, be further divided into the two-way radio frequency uplink service signal with suitable phase difference, respectively as the electrical modulation signal of two RSOA; When (2) the uplink service signal of optical network unit is radio frequency uplink service signal from wireless traffic access point AP, up radio frequency uplink service signal is divided into two-way and adds suitable phase difference and then as the electrical modulation signal of RSOA.With the input RSOA downlink optical signal as modulated light source, after the electrical modulation signal of inputting RSOA being carried in the downstream signal of input RSOA, two-way has loaded the descending light letter reflected light splitter 18 of electrical modulation signal, after the coupling of optical branching device 18, the up radio frequency light signal that the output coupling obtains.Wherein, above-mentioned coupling is the downlink optical signal that the two-way that above-mentioned two RSOA reflect has loaded electrical modulation signal to be carried out luminous power close the road.

Fig. 3 provides is the embodiment of uplink service signal when being base band uplink service signal.Such as Fig. 3, at up direction:

Radio-frequency signal source 11 produces the radio-frequency carrier signal of preset frequency, and exemplary generation frequency is the radio-frequency carrier signal of fs.In this example, the radio-frequency carrier signal that radio-frequency signal source produces is divided into two-way with the radio-frequency carrier signal of frequency homophase, and by first-phase shifting formwork piece the phase difference of above-mentioned two-way radio-frequency carrier signal is regulated, obtain to have the first poor radio-frequency carrier signal of predetermined phase and the second radio-frequency carrier signal.In the specific implementation, first-phase shifting formwork piece reaches the effect of the phase difference of regulating the two-way radiofrequency signal by regulating the wherein phase place of one road radio-frequency carrier signal.

Base band uplink service signal is divided into uniform two-way, and the uplink business data in the two-way base band uplink service signal is modulated to respectively above-mentioned two-way with frequently and have on the poor radio-frequency carrier signal of predetermined phase, with gained two-way radio-frequency carrier signal, i.e. the first radio-frequency carrier signal and the second radio-frequency carrier signal, electrical modulation signal as two RSOA, modulation realizes the sub-carrier modulation of radio frequency at this moment as the downstream signal of light source.In the specific implementation, by modulation module with the Data Modulation of base band uplink service signal to radio-frequency carrier, exemplarily, realize respectively the base band upward signal is modulated on the radio-frequency carrier signal by multiplier shown in Figure 3 13,14.

At optical branching device 18 places, after the two-beam u1 that two RSOA are reflected and u2 are coupled, be back to again optical branching device 3 rear continuation uplink.Wherein, this two-beam u1 and u2 are the first up radio frequency light signal and the second up radio frequency light signal that has loaded electrical modulation signal.Wherein, can regulate by the phase difference of 17 pairs of two-way radio-frequency carrier signals of second-phase shifting formwork piece, so that light u1 and the u2 of input optical branching device 18 have predetermined phase difference.Usually, after setting the phase difference of two-way radio-frequency carrier by first-phase shifting formwork piece, second-phase shifting formwork piece 17 roles are fine setting effects, so that reaching predetermined value, light u1 and u2 phase difference get, thereby, the up radio frequency light signal that is coupled out by optical branching device can reach predetermined requirement, as makes the up radio frequency light signal that is coupled out become the SSB signal.In the specific implementation, above-mentioned phase shift module can be embodied as phase-shifter.

Among this embodiment, key element is reflection type semiconductor image intensifer RSOA15 and RSOA16.In the specific implementation, adopt the RSOA of general commercial to get final product, there is no extra parameter value and limit.Reuse downstream wavelength, upstream data is carried out after the relevant treatment such as phase shift respectively via two RSOA modulation, and then realize the uplink optical signal of different modulating mode.

Such as Fig. 3, among this embodiment, the electric territory processing module that optical network unit comprises comprises: radio-frequency signal source 11, first-phase shifting formwork piece 12, the first multiplier 13, the second multiplier 14.Electricity territory processing module is modulated to base band uplink service signal on the radio-frequency carrier, and the radio-frequency carrier that the upward signal data are carried in output is that radio frequency uplink service signal is as the electrical modulation signal of input RSOA.In subsequent treatment, with the downstream signal of the RSOA reflection modulated light source as upward signal, realized reusing of downstream signal, and the reflection of upward signal when ONU does not possess light emission module, thereby realized the wavelength self adaptation of ONU.In this example, the effect of electric territory processing module is that base band uplink service signal loading is had on the poor radio-frequency carrier signal of predetermined phase, forms the radio frequency uplink service signal that can be used as different RSOA electrical modulation signal.

Further, by regulating the phase-shift value of above-mentioned first-phase shifting formwork piece and/or second-phase shifting formwork piece, can in the adaptive while of wavelength of realizing ONU, neatly upward signal be modulated to radio frequency single-side belt, the double-side band with certain frequency displacement or suppress optical carrier.Exemplarily, when the phase difference of two-way electrical modulation signal of two RSOA of input is 90 when spending, the up radio frequency light signal that optical network unit is sent to optical line terminal is the radio frequency single sideband singal of corresponding modulating on predetermined wavelength, and the downstream signal of exporting when optical line terminal is that wavelength is λ ₀Baseband signal, the upward signal that exports optical line terminal after RSOA-MI modulation to is the radio frequency single sideband singal with certain frequency displacement; When the phase difference of two-way electricity territory signal is 180 when spending, upward signal is the inhibition optical carrier of corresponding modulating on predetermined wavelength; When the phase difference of two-way electricity territory signal is 0 when spending, upward signal is that corresponding modulating is in the radio frequency double-sideband signal of predetermined wavelength.In sum, when downstream signal is baseband signal, the multi-wavelength passive optical network system of the embodiment of the invention can transmit uplink and downlink signals simultaneously on single fiber, thereby, when realizing full duplex, can suppress the adverse factors such as reverse Rayleigh scattering and optical fiber dispersion, avoided the impact of reverse Rayleigh scattering and optical fiber dispersion, thereby can under lower cost, realize the high-quality high speed transmission of signals of single fiber bi-directional.

Fig. 5 is the structural representation of the multi-wavelength passive optical network system of further embodiment of this invention.Among this embodiment, the uplink service signal of optical network unit directly is the radio frequency uplink service signal from wireless traffic access point AP, after the radio frequency uplink business data being divided into two-way and adding suitable phase difference as the electrical modulation signal of RSOA.Such as Fig. 5, the electric territory processing module of this embodiment comprises: third phase shifting formwork piece 19, be used for the up radiofrequency signal that is divided into the two-way transmission is carried out phase adjusted, input RSOA as two-way radio frequency upward signal, Third Road and the four road radio frequency upward signal of electrical modulation signal to obtain having poor being used for of predetermined phase.

Fig. 6 is among the present invention embodiment shown in Figure 4, when the phase difference of electric territory signal of input RSOA be 90 degree, when optical source wavelength is 1490 nanometer, the upward signal of radio frequency 5GHz is through the spectrogram of RSOA-MI structure output.By as shown in Figure 6, through the up radio frequency light signal of the radio frequency 5GHz of RSOA-MI structure output for being modulated at the radio frequency single sideband singal on 1490 nano wave lengths.

Fig. 7 is among the present invention embodiment shown in Figure 4, when the phase difference of electric territory signal of input RSOA be 90 degree, when optical source wavelength is 1550 nanometer, the upward signal of radio frequency 32GHz is through the spectrogram of RSOA-MI structure output.By as shown in Figure 7, through the up radio frequency light signal of the radio frequency 32GHz of RSOA-MI structure output for being modulated at the radio frequency single sideband singal on 1550 nano wave lengths.

Fig. 3, the optical line terminal side that shows embodiment illustrated in fig. 4 only have a transmitting element, and the situation of a corresponding optical network unit only.In specific implementation, can corresponding a plurality of optical network units in the optical line terminal.Therefore, can in optical line terminal, a plurality of optical transmission modules can be set, and increase wavelength division multiplexing wave multiplexer, channel-splitting filter realization optical-fiber network.Fig. 8 is in the embodiment of the invention, the structural representation of a plurality of passive optical network PON module-cascades of optical line terminal.CO (central office) represents central local side.

The embodiment of the invention also discloses a kind of multi-wavelength passive optical network system and realize the method for Wavelength reuse.Such as Fig. 9, the multi-wavelength passive optical network system of the embodiment of the invention realizes that the method for Wavelength reuse comprises:

Step 901, optical network unit is divided into the first via and the second tunnel with the downstream signal of the predetermined wavelength that optical line terminal sends;

In this step, in the specific implementation, the multi-wavelength signals that optical line terminal sends is decomposed into a plurality of single wavelength downstream signals by Wavelength division multiplexing module such as AWG according to wavelength, and these a plurality of single wavelength downstream signals correspond respectively to different optical network units;

Step 902, optical network unit receives described first via downstream signal, and with described the second road downstream signal as the modulated light source that is used for modulated RF uplink service signal, after described radio frequency uplink service signal is modulated, obtain up radio frequency light signal, and described up radio frequency light signal is sent to described optical line terminal.

Preferably, described method, wherein, described step B comprises:

Step B2, described the second road downstream signal is divided into the five the road and the six the tunnel, and with the described the five road and the six road downstream signal respectively as the modulated light source of described Third Road and the four road radio frequency uplink service signal, respectively described Third Road and the four road radio frequency uplink service signal are modulated, obtain that the two-way modulation obtains, have a poor up radio frequency light signal of predetermined phase, after the described up radio frequency light signal coupling that has after the modulation of the poor two-way of predetermined phase, and the up radio frequency light signal that coupling obtains is sent to described optical line terminal.

Described radio frequency uplink service signal is divided into two-way;

In conjunction with the multi-wavelength passive optical network system of the invention described above embodiment, the method for the realization Wavelength reuse of one embodiment of the invention comprises:

The multichannel downstream signal carries out direct intensity modulated at the multi wave length illuminating source place of OLT, and the modulated signal of multi-wavelength forms the multi-wavelength downstream signal;

Above-mentioned multi-wavelength downstream signal transfers to the ONU place through trunk optical fiber, wavelength division multiplexer, branch optical fiber, be divided into two bundles by optical branching device 3, the a branch of mediation as the received module solution of downstream signal recovered, and another bundle enters the modulating part of the upward signal of ONU, i.e. RSOA-MI;

The modulating part of the upward signal of described ONU utilizes optical branching device that light signal is divided into uniform two-way, enter respectively among the RSOA of underarm, RSOA because of have gain fast saturated and slow recovery characteristics the light signal of input had amplitude clamp down on effect, the optical signal magnitude after being reflected by RSOA changes little and then as the modulated light source of upward signal;

In the processing module of ONU electricity territory, upstream data is modulated on the radio-frequency carrier of two-way with quadrature frequently, with the two-way radiofrequency signal of the gained electrical modulation signal as two RSOA, to modulating as the downstream signal of light source this moment.The phase difference of regulating the two-way radio-frequency carrier signal can make the up radio frequency light signal of the rear gained of coupling realize the particular modulation form of SSB or OCS.

In the method for this embodiment, the descending multi-wavelength baseband signal of described WDM-PON, direct intensity modulation is adopted on each road; Upward signal is the subcarrier signal of multi-wavelength, and each road signal is SSB or the OCS signal that is modulated on the subcarrier of certain wavelength; Therefore uplink and downlink signals can transmit on single fiber simultaneously, and can not be subject to the impact of reverse Rayleigh scattering.Here subcarrier is once explained: have light source, light source that the light carrier of multi-wavelength is provided in the optical line terminal.And the radio frequency upward signal has been modulated on the light signal through RSOA namely by the signal that forms after the radio-frequency carrier modulation, and in the radio frequency light signal, originally the radio-frequency carrier on the meaning just becomes subcarrier at this moment.

Only there be special differing in electric territory signal among the electricity territory processing module input two-way RSOA with frequently.Like this, the light signal after the two RSOA reflection modulation can produce comparatively ideal particular modulation effect after optical branching device 18 couplings.For example, the two-way electricity territory signal of input RSOA differs when being 90 °, after the remodulates light signal coupling of two RSOA output, can realize optical SSB SSB modulation.The two-way electricity territory signal of input RSOA differs when being 180 °, after the remodulates light signal coupling of two RSOA output, can realize light suppressed carrier OCS modulation.

Compared with prior art, one of the present invention's technical scheme has the following advantages:

By having reused the downstream signal light of OLT transmission, with the modulated light source of these downlink optical signals as upward signal, can realize in ONU, need not being the special light source of upward signal configuration, thereby the configuration of all ONU is unified among the WDM-PON, be convenient to large-scale production and extensive buying, and then reduce cost.

Further, in the technical scheme of the embodiment of the invention, the up-downgoing light signal shares the light carrier of Same Wavelength, lower behavior baseband signal, upper behavior has been offset the radiofrequency signal of certain frequency, both saved wavelength resource, and overcome again among traditional single fiber list wavelength bidirectional WDM-PON and be subjected to reverse Rayleigh scattering to affect serious shortcoming;

Further, in the technical scheme of the embodiment of the invention, ONU need not configure the upper line light source of special wavelength, and ONU has Wavelength-independent, namely to the adaptivity of wavelength, is convenient to OLT from angle unified distribution and the scheduling wavelength resource of the whole network;

Further, the technical scheme of the embodiment of the invention can be in the wavelength adaptive ability that realizes ONU, can realize neatly having the upward signal of the particular modulation forms such as SSB or OCS, this flexibly modulation system reduces dispersion to the impact of radio frequency light signal being beneficial to;

Further, the ONU of the embodiment of the invention is in links such as light splitting and modulation, and Passive Optical Components all adopts waveguide devices, and active optical component is the RSOA device of compact conformation, and the overall structure volume is little, easy of integration, low in energy consumption;

Further, the applicable uplink and downlink signals speed symmetry of the technical scheme of the embodiment of the invention and asymmetrical two kinds of situations under low power condition, are reused downstream wavelength, carry out two-forty, high performance transmission;

Further, the technical scheme of the embodiment of the invention is applicable to the radiofrequency signal of several GHz-tens GHz more modulation forms, transmits efficiently apart from interior at Access Network under the lower-wattage.

The above only is preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims

1. multi-wavelength passive optical network system comprises: optical line terminal, Wavelength division multiplexing module and one or more optical network unit, it is characterized in that,

In the described optical network unit each comprises:

The upward signal modulation module, be used for the modulated light source of described the second road downstream signal as the radio frequency uplink service signal of optical network unit under the described upward signal modulation module, described radio frequency uplink service signal is modulated, and the up radio frequency light signal that modulation obtains is sent to described Wavelength division multiplexing module by described the first optical branch module, be sent to described optical line terminal by described Wavelength division multiplexing module;

Described each optical network unit also comprises:

2. multi-wavelength passive optical network system according to claim 1 is characterized in that, described upward signal modulation module comprises:

The second reflection type semiconductor image intensifer, be connected with the 4th branch and the described electric territory processing module of described the second optical branch module, be used for described the four road radio frequency uplink service signal being modulated as modulated light source with the described the six tunnel downstream signal, and the second up radio frequency light signal that obtains is modulated in output;

3. multi-wavelength passive optical network system according to claim 2, it is characterized in that, described upward signal modulation module is: be aided with the waveguide type Michelson's interferometer of reflection type semiconductor image intensifer, described first, second reflection type semiconductor image intensifer lays respectively at up and down two arms of described waveguide type Michelson's interferometer.

4. multi-wavelength passive optical network system according to claim 2 is characterized in that, when the uplink service signal of described optical network unit was base band uplink service signal, described electric territory processing module comprised:

Modulation module, be used for described base band uplink service signal is divided into two-way, and described two-way base band uplink service signal is modulated to respectively on described the first radio-frequency carrier signal and the second radio-frequency carrier signal, obtain to carry described Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal of described base band uplink service signal data.

5. multi-wavelength passive optical network system according to claim 1 is characterized in that, the phase difference of described Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal is: 0 degree, 90 degree or 180 degree.

6. multi-wavelength passive optical network system according to claim 4 is characterized in that, described upward signal modulation module also comprises:

7. multi-wavelength passive optical network system according to claim 2 is characterized in that, when the uplink service signal of described optical network unit was radio frequency uplink service signal, described electric territory processing module comprised:

8. multi-wavelength passive optical network system according to claim 1 is characterized in that, each in the described optical network unit also comprises:

9. multi-wavelength passive optical network system according to claim 1 is characterized in that, the multi-wavelength downstream signal that described optical line terminal sends is: the single wavelength downstream signal of multichannel is carried out the multi-wavelength downstream signal that forms behind the direct intensity modulation.

10. the method for a multi-wavelength passive optical network system realization Wavelength reuse is characterized in that, comprising:

Step B, optical network unit receives described first via downstream signal, and with described the second road downstream signal as the modulated light source that is used for modulated RF uplink service signal, after to described radio frequency uplink service signal modulation, obtain up radio frequency light signal, and described up radio frequency light signal is sent to described optical line terminal;

Described step B comprises:

11. method according to claim 10 is characterized in that, when the uplink service signal of described optical network unit was base band uplink service signal, described step B1 comprised:

The described base band uplink service signal that optical network unit is sent is divided into two-way, described two-way base band uplink service signal is modulated to respectively on described the first radio-frequency carrier signal and the second radio-frequency carrier signal, obtains to carry described Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal of described base band uplink service signal data.

12. method according to claim 10 is characterized in that, when the uplink service signal of described optical network unit was radio frequency uplink service signal, described step B1 comprised:

Described radio frequency uplink service signal is divided into two-way;

13. each described method is characterized in that according to claim 10-12, described optical network unit is realized above-mentioned steps B by the upward signal modulation module, and described upward signal modulation module comprises:

14. an optical network unit is characterized in that, comprising:

The upward signal modulation module, be used for the modulated light source of described the second road downstream signal as the radio frequency uplink service signal of optical network unit under the described upward signal modulation module, described radio frequency uplink service signal is modulated, and the up radio frequency light signal that modulation obtains is sent to described optical line terminal;

15. optical network unit according to claim 14 is characterized in that, described upward signal modulation module comprises:

16. optical network unit according to claim 15, it is characterized in that, described upward signal modulation module is: be aided with the waveguide type Michelson's interferometer of reflection type semiconductor image intensifer, described first, second reflection type semiconductor image intensifer lays respectively at up and down two arms of described waveguide type Michelson's interferometer.

17. optical network unit according to claim 15 is characterized in that, when the uplink service signal of described optical network unit was base band uplink service signal, described electric territory processing module comprised:

18. optical network unit according to claim 14 is characterized in that, the phase difference of described Third Road radio frequency uplink service signal and the four road radio frequency uplink service signal is: 0 degree, 90 degree or 180 degree.