WO2008034378A1

WO2008034378A1 - A wave division multiplexing optical access transmission system, method and device

Info

Publication number: WO2008034378A1
Application number: PCT/CN2007/070575
Authority: WO
Inventors: Jun Zhao; Xuliang Zhang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-08-28
Filing date: 2007-08-28
Publication date: 2008-03-27
Also published as: CN101136701A; CN101136701B

Abstract

A wave division multiplexing optical access transmission system, method and device are disclosed. The system includes: an optical line terminal, many optical network units, and a remote nodes connecting the optical line terminal and the optical network unit through a fiber; wherein, the optical line terminal includes broad-spectrum light sources and many first wave division multiplexers; the remote node includes many third wave division multiplexers, and the second optical splitter device coupled to the third wave division multiplexer, for dividing the one branch optical signal to multiple branches optical signals in the form of wavelength crossing, and transmitting each branch optical signal to the third wave division multiplexer, respectively, either or for collecting the multiple branches optical signals outputted from many third wave division multiplexers, combining them in one branch optical signal and transmitting said optical line terminal. The present invention can improve the user number of wave division multiplexing passive optical network system.

Description

Wavelength division multiplexing optical access transmission system, method and device

This application claims priority to Chinese Patent Application No. 200610037323.3, entitled "Wavelength Division Multiplexed Optical Access Transmission System and Method", filed on August 28, 2006, the entire contents of which are incorporated by reference. In this application.

Technical field

The present invention relates to the field of transmission technologies, and in particular, to a wavelength division multiplexing optical access transmission system, method and device.

Background technique

In order to meet the rapid growth of data communication services, optical fiber networks have been rapidly developed, especially passive optical network (PON) access technologies have been rapidly developed. At present, relatively mature passive optical networks include: ATM-based Passive Optical Network (APON), Ethernet-based Passive Optical Network (EPON), and broadband-free Broadband Passive Optical Networks (BPON) and Gigabit Passive Optical Network (GPON), which are all TDM (Time Division Multiplex)/TDMA (Time Division Multiple Access). The time division multiple access mode accesses the user, and all users share the system uplink and downlink bandwidth. In these passive optical networks, in the downstream direction, the passive optical splitter splits the downstream optical power into multiple beams and sends them to the user, that is, an ONU (Optical Network Unit), in which all the users' data are modulated. The user extracts the part of the data according to his own address characteristics, that is, the TDM mode used in the downlink direction. In the uplink direction, in order to avoid the conflict, the TDMA mode is used for multiple access control, that is, the OLT (Optical Line Terminal) The terminal allocates some dedicated time slots (which may be continuous or discontinuous) to each user, and only allows the user to send uplink data in the time slot allocated to itself, and the uplink optical signal sent by the user passes through The source splitter is sent to the OLT of the system.

The passive optical network has too much optical power attenuation caused by the passive optical splitter, which will result in a very limited number of users per passive optical network. In addition, since all users in the network share the uplink and downlink bandwidth, each will result in The net bandwidth used by users is not high, and the utilization rate of the network is low. Moreover, because all users in the network share wavelengths for communication, communication security with poor security performance will be generated during communication. In order to overcome the shortcomings of the passive optical network itself, a wavelength division multiplexing optical connection combining the broadband characteristics of Wave Division Multiplexer (WDM) technology and the economic characteristics of a passive optical network The passive optical network (WDM-PON) has attracted wide attention in the industry.

As shown in FIG. 1 , it is a schematic diagram of a topology of a conventional wavelength division multiplexing optical access transmission system, which can realize transmission of multiple optical signals of different wavelengths in the same optical fiber (including uplink transmission and downlink). Transfer).

The optical line terminal 100 includes two Broadband Light Sources (BLS) 111 and 112, which serve as a downstream injection source and an upstream injection source, respectively, and the downstream injection source and the upstream injection source respectively have different bands.

The downlink transmission process is as follows:

The wide-spectrum light emitted by the down-width broad-spectrum light source 111 enters an Array Wave Guide (AWG) 130 through a Circulator 120 to split the broad-spectrum light into beams of different wavelengths, and corresponding to the arrayed waveguide grating 130. The channel output is divided by the wavelength division multiplexer 143 and injected into the loopback light source 142;

The loopback light source 142 emits light of a wavelength equal to that of the injected light, and through the turn-on and turn-off of the loopback light source 142, modulates the downlink data signal into its output light, and passes through the multiplexing of the wavelength division multiplexer 143. Output light is injected into the arrayed waveguide grating 130;

The arrayed waveguide grating 130 combines the optical waves of the respective channels, passes through the circulator 120, enters the optical fiber and transmits it to the remote node (RN) 150, and outputs it from the output channel of the arrayed waveguide grating 151 in the remote node 150. The split multiplexer 163 demultiplexes and finally enters the receiver 161 of the user terminal 160 to receive downlink data.

The uplink transmission process is similar to the downlink transmission process. The transmission process is as follows:

The wide-spectrum light emitted by the upstream broad-spectrum light source 112 passes through the circulator 120 into the arrayed waveguide grating 151 in the remote node 150, splits the broad-spectrum light into beams of different wavelengths, and passes the wave division from the corresponding channel of the arrayed waveguide grating 130. The output of the processor 163 is injected into the loopback light source 162; the loopback light source 162 emits light of a wavelength equal to the injected light, and the up data signal is modulated into the output light by the turn-on and turn-off of the loopback light source 162, and then passes through the wave. After multiplexing the multiplexer 163 and the arrayed waveguide grating 151, the output optical path is returned to the circulator 120, and the output light is wavelength-decomposed by the arrayed waveguide grating 130, and beams of different wavelengths are received and received by the wavelength division multiplexer 143. 141. Since the wavelength division multiplexing optical access transmission system allocates one wavelength to each user, it is essentially point-to-point communication, but the physical structure is a point-to-multipoint structure. Therefore, the network system has high transmission speed and cost. Economic advantages; In addition, each user has a unique wavelength, bandwidth can be guaranteed, and confidentiality is good.

However, in the process of implementing the present invention, the inventors have found that existing wavelength division multiplexed optical access transmission systems have at least the following drawbacks:

1. The number of users in the system is limited by the number of wavelength channels. For example, in the current C-band, if the interval is 0.8 nm, only 48 wavelength channels can be divided.

2. In addition, after the broad spectrum source is split by the spectrum of the arrayed waveguide grating, a large part of the optical power is filtered out and cannot be fully utilized.

Therefore, how to increase the number of users that a WDM-PON system can accommodate at a lower cost has become an important research topic for promoting the practical application of the wavelength division multiplexing optical access transmission system.

Summary of the invention

Embodiments of the present invention provide a wavelength division multiplexing optical access transmission system, method, and device, which can increase the number of access users of a WDM-PON system at a lower cost.

A wavelength division multiplexing optical access transmission system provided by the embodiment of the present invention includes: an optical line terminal and a point;

The optical line terminal includes a wide spectrum light source and a plurality of first wavelength division multiplexers, and each of the channel lines of the first wavelength division multiplexer is respectively connected to an optical transceiver unit of the optical line terminal;

The remote node includes a plurality of third wavelength division multiplexers, and each of the channel lines of each third wavelength division multiplexer is respectively connected to one of the optical network units;

The remote node further includes a second beam splitting device coupled to the third wavelength division multiplexer for splitting one optical signal into multiple optical signals in the form of wavelength crossover, and transmitting each optical signal separately A third wavelength division multiplexer, or a plurality of optical signals for aggregating the outputs of the plurality of third wavelength division multiplexers, are combined into one optical signal for transmission to the optical line terminal.

A wavelength division multiplexing optical access transmission system provided by the embodiment of the present invention includes: an optical line terminal and a point; The optical line terminal includes a wide spectrum light source and a plurality of first wavelength division multiplexers, and each of the channel lines of the first wavelength division multiplexer is respectively connected to one optical transceiver unit of the optical line terminal;

The optical line terminal further includes a first optical splitting device coupled between the first wavelength division multiplexer and the third wavelength division multiplexer, configured to divide one optical signal into multiple optical signals in a wavelength crossover manner, Each optical signal is separately transmitted to a first wavelength division multiplexer, or used to aggregate multiple optical signals output by the plurality of first wavelength division multiplexers, and combined into one optical signal for transmission to the remote node.

A wavelength division multiplexing optical access transmission method provided by an embodiment of the present invention includes:

The optical signal emitted by the broad spectrum light source of the optical line terminal is divided into multiple optical signals in the form of wavelength crossing;

Decomposing each of the optical signals into a plurality of optical signals of different wavelengths, and respectively performing data signal modulation on the optical signals of different wavelengths;

The modulated optical signals are multiplexed, and the multiplexed optical signals are combined into one optical signal and transmitted to the optical network unit via the remote node.

The modulated optical signals are multiplexed, and the plurality of multiplexed optical signals are combined into one optical signal and transmitted to the optical line terminal through the optical fiber.

An optical line terminal according to an embodiment of the present invention includes a wide spectrum light source and a plurality of wavelength division multiplexers, wherein each of the channel lines of each of the wavelength division multiplexers respectively connect one light of the optical line terminal The transceiver unit further includes:

a light splitting device coupled to the wavelength division multiplexer for splitting one optical signal into multiple optical signals in a wavelength crossover manner, and transmitting each optical signal to one of the wavelength division multiplexers, or And multiplexing the plurality of multiplexed optical signals into one optical signal and transmitting the optical signals to the optical network unit. A network device is provided for connecting to an optical line terminal and an optical network unit by using an optical fiber, and includes a plurality of wavelength division multiplexers, where each channel line of each wavelength division multiplexer is separately Connecting an optical network unit also includes:

a light splitting device coupled to the wavelength division multiplexer for splitting one optical signal into multiple optical signals in a wavelength crossover manner, and transmitting each optical signal to one of the wavelength division multiplexers, Or for collecting a plurality of optical signals output by the plurality of wavelength division multiplexers, and combining the plurality of multiplexed optical signals into one optical signal for transmission to the optical line terminal.

Compared with the prior art, since the comb-shaped filtering unit is introduced in the optical line terminal and the remote node according to the embodiment of the present invention, the odd-numbered wavelength and the even-numbered wavelength in the optical signal are separated by the comb-shaped filtering unit in the form of wavelength crossing. Wide-spectrum optical signal or multi-wavelength optical signal is divided into multiple optical signals, and each optical signal is further processed by a wavelength division multiplexer to correspond to a plurality of optical signals of different wavelengths transmitted in the optical channel, so The embodiment of the present invention makes full use of a part of the optical signal that has been filtered out in the past, and uses a wide-spectrum optical signal or a multi-wavelength optical signal of the same spectral density, which can greatly increase the number of optical channels served to the user.

DRAWINGS

FIG. 1 is a schematic diagram of a topology of a conventional wavelength division multiplexing optical access transmission system.

2 is a schematic top view of a wavelength division multiplexing optical access transmission system according to a first embodiment of the present invention. FIG. 3 is a schematic diagram showing the working principle of the comb filter mentioned in the embodiment of the present invention.

4 is a schematic top view of a comb filter unit mentioned in the embodiment of the present invention.

Fig. 5 is a schematic diagram of a wavelength division multiplexed optical access transmission system for the comb filter unit shown in Fig. 4. 6 is a schematic diagram of a topology of a wavelength division multiplexing optical access transmission system according to a second embodiment of the present invention. detailed description

Please refer to FIG. 2, which is a schematic diagram of a wavelength division multiplexing optical access transmission system according to an embodiment of the present invention. The system is a wavelength division multiplexing passive optical network (WDM-PON) system, the system comprising: an optical line terminal 210, and a remote node connecting the optical line terminal 210 and the plurality of distributed optical network units 230 through optical fibers (Remote Node, RN) 220. among them,

The optical line terminal 210 includes:

a wide-spectrum light source 211 and a broad-spectrum light source 212 respectively used as an upstream light source and a descending light source, and the two broad-spectrum light sources are connected to the circulator 213; a first comb filtering unit 214 connected to the circulator 213;

a plurality of first wavelength division multiplexers 215 coupled to the first comb filter unit 214, each of the first wavelength division multiplexers 215 separating the multiple optical channels;

a plurality of second wavelength division multiplexers 216, one side connected to one optical channel of a first wavelength division multiplexer 215, and the other side connected to the first loop light source 217 and the first receiver 218, the first The loop light source 217 and the first receiver 218 constitute an optical transceiver unit of the optical line terminal 210;

The first comb filtering unit 214 is configured to divide one optical signal into multiple optical signals in the form of wavelength crossover, and transmit each optical signal to a first wavelength division multiplexer 215; or for multiple The plurality of optical signals output by the first wavelength division multiplexer 215 are combined in the form of wavelength crossings to transmit one optical signal to the remote node 220.

The remote node 220 includes:

a second comb filter unit 221 is connected to the circulator 213 through an optical fiber;

a plurality of third wavelength division multiplexers 222 are coupled to the second comb filter unit 221, and each third wavelength division multiplexer 222 branches out multiple optical channels;

a plurality of fourth wavelength division multiplexers 231, one side of which is connected to one optical channel of a third wavelength division multiplexer 222, and the other side of which is connected to the second loop light source 232 and the second receiver 233; The wavelength division multiplexer 231, the second loop light source 232 and the second receiver 233 constitute a network unit 230;

The second comb filtering unit 221 is configured to divide an optical signal into multiple optical signals in the form of wavelength crossover, and transmit each optical signal to a third wavelength division multiplexer 222; or The plurality of optical signals output by the third wavelength division multiplexer 222 are combined into one optical signal in the form of wavelength crossover to be transmitted to the optical line terminal 210.

The first comb filter 214 and the second comb filter 221 have the same working principle, as shown in FIG.

The comb filter is a three-port device, one is an input port, and the other two are output ports (as shown by the solid line in Figure 3); or, two are input ports and the other is an output port (as in Figure 3). Shown in dotted line). The comb filter is configured to split an optical signal of an odd-numbered wavelength and an even-numbered optical signal into two optical signals in a wavelength crossover manner according to a wavelength of the optical signal, according to a wavelength of the optical signal, respectively. Output from two output ports; conversely, the comb filter is used to combine two optical signals input from two input ports in the form of odd-numbered wavelengths and even-numbered wavelengths. It is an optical signal and is output from the output port.

For example, in the C-band, the wavelength division multiplexer divides the optical signal into transmission channels of up to 48 optical signals according to the wavelength at intervals of 0.8 nm; in the embodiment of the present invention, since the comb filter is used, the light is used. After the signals are separated into two paths, each optical signal can be split into optical signals transmitted by 48 optical channels through a wavelength division multiplexer. Therefore, the embodiment of the present invention doubles the number of optical channels, that is, The number of users of the WDM-PON system can be doubled.

In addition, in the embodiment of the present invention, the first comb filter 214 and the second comb filter 221 may be replaced by comb filter units, which are cascaded by at least two comb filters. The composition, as shown in FIG. 4, is a comb filter unit composed of three comb filters cascaded. The comb filter 1 divides the wide-spectrum optical signal or the multi-wavelength optical signal into two optical signals of intersecting wavelengths, and then the comb filter 2 and the comb filter 3 divide the two optical signals into separate signals. Two cross-wavelength optical signals. Therefore, the comb filter unit increases the spectral density of the optical signal by a factor of four. Accordingly, the WDM-PON system using the comb-filter unit of the two-stage interconnection can increase the number of users by four times, that is, to 192 users, compared with the prior art.

Referring to FIG. 5, the first comb filtering unit 514 and the second comb filtering unit 521 are schematic diagrams of a WDM-PON system using the comb filter unit of the two-stage interconnection shown in FIG. Its working principle is similar to that of Figure 2 and will not be described in detail here.

Correspondingly, an embodiment of the present invention provides a wavelength division multiplexing optical transmission method, which is applied to the foregoing wavelength division multiplexing optical access transmission system of FIG. 2 or FIG. 5, which includes downlink optical signal transmission and uplink. The optical signal transmission process is now described in detail in conjunction with Figure 2:

The working process of its downlink optical transmission is as follows:

The optical signal of the broadband light or the multi-wavelength light emitted by the down-width broad spectrum light source 212 is directionally transmitted to the first comb filter 214 via the circulator 213;

The first comb filter 214 divides the input optical signal into two optical signals in the form of wavelength crossing, and respectively enters two first wavelength division multiplexers 215 connected to the output end thereof;

The first wavelength division multiplexer 215 performs a wavelet processing on the optical signal input from the input end, and is divided into a plurality of optical transmission channels, each of which transmits optical signals of different wavelengths;

The optical signal of each channel is processed by the demultiplexing (demultiplexing) of the second wavelength division multiplexer 216, and the optical signal is injected into the first loopback light source 217; The first loopback light source 217 emits an optical signal of a wavelength equal to the injected optical signal, and modulates the output of the data signal to be transmitted to the output of the first loopback light source 217 by opening and closing the switch of the first loopback light source 217. In the light signal;

The second wavelength division multiplexer 216 performs multiplexing (multiplexing) processing on the output optical signals of the plurality of first loopback light sources 217;

The first wavelength division multiplexer 215 multiplexes optical signals of different wavelengths for each channel, and outputs the same as an optical signal;

The first comb filter 214 combines the two optical signals respectively output by the two first wavelength division multiplexers 215 in a wavelength crossing manner, and passes through the circulator 213 to enter the remote node 220;

The second comb filter 221 in the remote node 220 approximates the optical signal to a first comb filter

214, the optical signal is divided into two paths in the form of wavelength crossing, respectively entering two third wavelength division multiplexers 222;

The third wavelength division multiplexer 222 demultiplexes the optical signal into signals of a plurality of wavelengths in a manner similar to the first wavelength division multiplexer 215, and the optical signals of each wavelength are respectively transmitted on different optical transmission channels. The optical signal transmitted by each optical transmission channel passes through the optical fiber, enters the fourth wavelength division multiplexer 231, and the optical signal is demultiplexed by the fourth wavelength division multiplexer 231, and sent to the second receiver 233, the optical signal. The data signal is recovered by the middle.

The working process of the uplink optical transmission of the system is similar to the working process of the downlink optical transmission, which is roughly as follows:

The wide-spectrum optical signal or multi-wavelength optical signal emitted by the uplink broad-spectrum light source 211 is transmitted to the remote node 220 via the circulator 213 and the optical fiber;

The second comb filter 221 in the remote node 220 is divided into two optical signals in a wavelength crossing manner, and respectively enters the third wavelength division multiplexer 222, and each optical signal is divided into different by the third wavelength division multiplexer 222. The wavelengths are transmitted to the optical network unit 230 corresponding to different optical channels;

The optical network unit 230 first performs a demultiplexing process by the fourth wavelength division multiplexer 231 to inject the optical signal into the second loopback light source 232, and the second loopback light source 232 is transmitted in a similar manner to the first loopback light source 217. The data signal is modulated into the output optical signal of the second loopback light source 232; then, the output optical signal is returned to the first loop filter 214 through the remote node 220, the circulator 213;

The first comb filter 214 divides the optical signal into two paths in an intersecting manner, and respectively enters two first The wavelength division multiplexer 215, after each optical signal is demultiplexed by the first wavelength division multiplexer 215, after the optical signal transmitted by each optical channel is processed by the second wavelength division multiplexer 216, The transmitted data signal is received by the first receiver 218.

In summary, since the comb filter unit is introduced in the optical line terminal and the remote node in the embodiment of the present invention, the wide spectrum optical signal or the multi-wavelength optical signal is divided into multiple optical signals by wavelength crossover through the comb filter unit. Each of the optical signals is further divided by the wavelength division multiplexer into optical signals of different wavelengths corresponding to the plurality of optical channels. Therefore, the embodiment of the present invention uses wide-spectrum optical signals or multi-wavelength lights of the same spectral density. The signal can greatly improve the number of optical channels served to the user; in addition, since the comb filter constituting the comb filter unit has better isolation of the optical signals transmitted by the optical channels, although the comb filter unit is used, the difference is different. The wavelength interval of the optical signal transmitted by the optical channel is narrowed, but the isolation between the optical signals of different wavelengths is still higher than the isolation between the optical signals of the output of the single wavelength division multiplexer in the prior art, and therefore, the present invention The crosstalk of the optical signals transmitted by the different optical channels of the embodiment is small.

In addition, the same wavelength can be used in the uplink and downlink directions. Referring to FIG. 6, a schematic diagram of the wavelength division multiplexing optical access transmission system of the second embodiment of the present invention is shown:

The difference from the embodiment shown in FIG. 2 is that: in this embodiment, the wide-spectrum light source 211 in the embodiment shown in FIG. 2 is omitted, and the fourth wavelength division multiplexer 231 in the embodiment shown in FIG. 2 is simultaneously removed. The replacement is the spectroscope 60 in this embodiment.

In this embodiment, the operation principle in the downward direction is basically the same as that in the embodiment shown in Fig. 2, and in the upward direction, the difference is caused by omitting the wide-spectrum light source 211. The working principles of the downlink and uplink directions are detailed as follows:

Downstream optical transmission process:

The embodiment is substantially the same as the embodiment shown in FIG. 2, except that the processing of the downlink light in the optical network unit 630: the optical signal transmitted by each optical transmission channel passes through the optical fiber, enters the optical splitter 60, and is configured by the optical splitter. The power signal is split (eg, 50%: 50%), wherein a portion of the optical power is transmitted to the second receiver 233, and another portion of the optical power is sent to the second loopback source 232.

Upstream optical transmission process:

The same as in the embodiment shown in FIG. 2, except that the optical network unit 630 actually remodulates the downstream optical signal through the second loopback light source 232: the optical splitter 60 will have a part of the optical signal (eg 50%) Injecting into the second loopback light source 232, the second loopback light source 232 is used with the first loopback The light source 217 modulates the transmission data signal into the output optical signal of the second loopback light source 232 in a similar manner; then, the output optical signal returns to the original path, passes through the remote node 220, the circulator 213, and enters the first comb filter 214.

It should be noted that the comb filtering unit in each embodiment may be not only a comb filter or a comb filter of at least two levels of interconnection, but also other methods capable of dividing one optical signal by wavelength. A beam splitter for multiple optical signals.

In the embodiment of the present invention, a comb filter unit is introduced at both the optical line terminal and the remote node, and the wide spectrum optical signal is obtained by separating the odd-numbered wavelength and the even-numbered wavelength in the optical signal by the comb-shaped filtering unit in the form of wavelength crossing. The multi-wavelength optical signal is divided into multiple optical signals, and each optical signal is further processed by a wavelength division multiplexer to correspond to a plurality of optical signals of different wavelengths transmitted in the optical channel. Therefore, the embodiment of the present invention makes full use of the optical signal. Part of the optical signal that has been filtered out in the past, using a wide-spectrum optical signal or a multi-wavelength optical signal of the same spectral density, can greatly increase the number of optical channels that serve the user.

In addition, since the comb filter constituting the comb filter unit has good isolation of the optical signals transmitted by the respective optical channels, although the wavelength interval of the optical signals transmitted by the different optical channels is narrowed after the comb filter unit is used, The isolation between the optical signals of different wavelengths is still higher than that between the optical signals of the output of the single wavelength division multiplexer in the prior art. Therefore, the crosstalk of the optical signals transmitted by different optical channels in the embodiment of the present invention is higher. small.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and the equivalent changes made by the scope of the present invention remain within the scope of the present invention.

Claims

Rights request

A wavelength division multiplexing optical access transmission system, comprising: an optical line terminal, a plurality of optical network units, the optical line terminal comprising a wide spectrum light source and a plurality of first wavelength division multiplexers, the first Each of the channel lines of the wavelength division multiplexer is respectively connected to an optical transceiver unit of the optical line terminal;

The remote node further includes a second beam splitting device coupled to the third wavelength division multiplexer, configured to divide one optical signal into multiple optical signals in the form of wavelength crossover, and each channel The optical signals are respectively transmitted to a third wavelength division multiplexer or a plurality of optical signals for collecting the outputs of the plurality of third wavelength division multiplexers, and are combined into one optical signal for transmission to the optical line terminal.

2. The wavelength division multiplexed optical access transmission system according to claim 1, wherein the optical line terminal further comprises a coupling between the first wavelength division multiplexer and the third wavelength division multiplexer. a first beam splitting device, configured to divide an optical signal into multiple optical signals in the form of wavelength crossover, respectively transmit each optical signal to a first wavelength division multiplexer, or to aggregate multiple first wavelength divisions The multiple optical signals output by the multiplexer are combined into one optical signal for transmission to the remote node.

The wavelength division multiplexing optical access transmission system according to claim 2, wherein the first beam splitting device and the second beam splitting device each comprise a comb filter having at least two stages of interconnection.

The wavelength division multiplexing optical access transmission system according to claim 2, wherein the first beam splitting means and the second beam splitting means are each a comb filter.

The optical line terminal further includes a first beam splitting device coupled between the first wavelength division multiplexer and the third wavelength division multiplexer, configured to divide one optical signal into multiple wavelengths. a road light signal, which transmits each optical signal to a first wavelength division multiplexer or a plurality of first waves The multiple optical signals output by the multiplexer are combined into one optical signal for transmission to the remote node.

6. The wavelength division multiplexed optical access transmission system according to claim 5, wherein the remote node further comprises a second optical splitting device coupled to the third wavelength division multiplexer for An optical signal is divided into multiple optical signals in the form of wavelength crossover, and each optical signal is separately transmitted to a third wavelength division multiplexer, or used to aggregate multiple output of the third wavelength division multiplexer output. The optical signals are combined into one optical signal for transmission to the optical line terminal.

The wavelength division multiplexing optical access transmission system according to claim 6, wherein the first beam splitting device and the second beam splitting device each comprise a comb filter having at least two stages of interconnection.

The wavelength division multiplexing optical access transmission system according to claim 6, wherein the first spectroscopic device and the second spectroscopic device are each a comb filter.

A wavelength division multiplexing optical access transmission method, comprising:

The wavelength division multiplexing optical access transmission method according to claim 9, wherein the method further comprises:

The remote node divides the optical signal from the optical fiber into multiple optical signals in the form of wavelength crossover, and demultiplexes the optical signals into respective optical network units.

The wavelength division multiplexing optical access transmission method according to claim 9, wherein the step of separately performing data signal modulation on the optical signals of different wavelengths comprises:

Injecting each of the optical signals of different wavelengths into a corresponding first loopback light source;

The first loopback source modulates a data signal to be transmitted into the injected optical signal and outputs the modulated optical signal.

The wavelength division multiplexing optical access transmission method according to any one of claims 9 to 11, characterized in that the wide spectrum light source of the optical line terminal is emitted by using at least two stages of comb filters Optical signal is divided into multiple optical signals in the form of wavelength crossing, and the multiplexed optical signals are multiplexed Combined into one optical signal.

The wavelength division multiplexing optical access transmission method according to any one of claims 9 to 11, characterized in that the optical signal emitted by the broad spectrum light source of the optical line terminal is detected by a comb filter The form of wavelength crossing is divided into multiple optical signals, and the multiplexed multiple optical signals are combined into one optical signal.

The wavelength division multiplexing optical access transmission method according to claim 14, wherein the method further comprises:

The optical line terminal divides the optical signal from the optical fiber into multiple optical signals in the form of wavelength crossover, and demultiplexes the optical signals into a receiver.

The wavelength division multiplexing optical access transmission method according to claim 14, wherein the step of separately performing data signal modulation on the optical signals of different wavelengths comprises:

Injecting each of the optical signals of different wavelengths into a corresponding second loopback light source;

The second loopback source modulates a data signal to be transmitted into the injected optical signal and outputs the modulated optical signal.

The wavelength division multiplexing optical access transmission method according to any one of claims 14 to 16, characterized in that the light emitted by the broad spectrum light source of the optical network unit is used by a comb filter of at least two stages of interconnection The signal is divided into multiple optical signals in the form of wavelength crossings, and the plurality of multiplexed optical signals are combined into one optical signal.

The wavelength division multiplexing optical access transmission method according to any one of claims 14 to 16, characterized in that the optical signal emitted by the broad spectrum light source of the optical network unit is crossed by wavelength by using a comb filter. The form is divided into multiple optical signals, and the plurality of multiplexed optical signals are combined into one optical signal.

An optical line terminal comprising a wide spectrum light source and a plurality of wavelength division multiplexers, each of the channel lines of each of the wavelength division multiplexers being respectively connected to an optical transceiver unit of the optical line terminal, It is characterized by:

a light splitting device coupled to the wavelength division multiplexer for splitting one optical signal into multiple optical signals in a wavelength crossover manner, and transmitting each optical signal to one of the wavelength division multiplexers, or And multiplexing the plurality of multiplexed optical signals into one optical signal and transmitting the optical signals to the optical network unit.

The optical line terminal according to claim 19, wherein the spectroscopic device comprises a comb filter interconnected by at least two stages.

The optical line terminal according to claim 19, wherein the spectroscopic device is a comb filter. And a plurality of wavelength division multiplexers, each of the channel lines of each of the wavelength division multiplexers is connected to an optical network unit, and the method further includes:

23. The network device according to claim 22, wherein the spectroscopic device comprises a comb filter interconnected by at least two stages.

24. The network device according to claim 22, wherein the spectroscopic device is a comb filter.