WO2007143945A1 - Wavelength routing module, system and method therewith - Google Patents

Abstract

A wavelength routing module, the system and the method therewith include at least one optical network terminal (OLT), an optical distribution network (ODN), and at least one optical network unit (ONU); Said OLT transmits an optical signal bearing downlink data and a non-modulation optical signal bearing non-data to the ONU through the ODN. Said wavelength routing module, which is used for outputting multiple input signals to any output port, includes : the splitter/combiner for multiplexing and demultiplexing received signals; the multiple branches for distributing/combining received optical signals, one side ports of which connect to the multiple second splitters/combiners; and the router for switching between different output ports and outputting optical signals to any output port; one side ports of the router connect to the other side ports of the multiple branches, and the other side ports of the router connect to the multiple second fibers. The present invention can realize the interchangeability between different carrier's ONUs, and make it more convenient for carriers to distribute services.

Description

 Passive optical network system and method for wavelength routing module and wavelength routing module

[1] Technical field

 [2] The present invention relates to a passive optical network system, and more particularly to a passive optical network system that can arbitrarily route optical signals of different wavelengths to any colorless optical network unit.

[3] Background of the invention

 [4] At present, many Internet services usually pass rates from 56K respectively.

 To several megabit dial-up modems, asymmetric digital line subscriber lines (ADSL

 ), cable modem (CM:), VDSL

 Wait for access. However, in order to provide various services, such as high-quality video information services, VoD (Video on Demand) services, etc., data transmission requires approximately 100 Mbps.

 The bandwidth of the above-mentioned access methods cannot meet the requirements. Therefore, the demand for laying access networks with optical fibers is rapidly increasing, and passive optical networks (P0N)

 It is a user access network that can meet these new business needs and is economical, easy to operate and maintain, as shown in Figure 1. figure 1

 A prior art passive optical network system is shown. In general, a passive optical network system includes a central office 102, an optical distribution network 104, and a plurality of optical network units (ONUs, Optical Network Units), which are implemented according to P0N, P0N.

 Can be divided into different types, namely ATM-P0N using ATM, EP0N (Ethernet Over PON) based on Ethernet, GP0N with gigabit rate, using wavelength division multiplexing

 WDM-P0N, and 0CMDA-P0N with optical CDMA.

[5] Wavelength Division Multiplexing System ( WDM - P0N

 Due to its huge bandwidth capacity and information security similar to peer-to-peer communication, it has attracted wide attention from global communication experts, but WDM-P0N

 Network equipment is complex and costly, so it has not been commercially viable. In recent years, due to the development of optical communication technology, the price of related optical communication devices has declined, WDM-P0N

Once again becoming a hotspot in the global communications industry, many equipment vendors and communications experts are reducing WDM - P0N A lot of in-depth research has been done on the complexity of network equipment and cost reduction, among which South Korea and the United States are the most. These studies have solved a large number of technical difficulties and have achieved great results in reducing costs, such as outdoor arrayed waveguide gratings (AWG, Array Waveguide Grating).

 Temperature control compensation technology, non-thermal arrayed waveguide grating technology, multi-wavelength light source technology in optical line terminal (0LT, Optical Line Terminal), light reflection amplification technology in 0, injection-locked light source technology in 0, etc. Great progress.

[6] At the same time, due to the high investment cost of laying telecommunications infrastructure, there are many interest entities involved, many restrictions on policies, laws and regulations, and the telecommunications operators involved have exclusive reasons. The telecommunications infrastructure is basically monopolized by traditional telecom operators. However, unbundled access to the local loop ( Unbundled Access to the Local Loop

 ), which is of great significance for deepening competition in the telecommunications market. For the promotion of local fixed-telephone services, Internet broadband access services and other telecommunications services, to avoid redundant construction of telecommunications infrastructure, consumers can enjoy cost-effective telecommunications services. It can play an important role and promote the development of a national telecommunications market. Therefore, the United States, the United Kingdom and other EU countries, Australia, Singapore, Japan, Hong Kong and other countries and regions have successively formulated a local loop unbundled access system. However, judging from the implementation of the foreign local loop unbundled access system, relying solely on the control measures of the telecommunications law, it is impossible to introduce sufficient competition in the access network field.

 [7] As the most promising next generation access network, WDM-P0N

 The natural characteristics of the network can well assist the implementation of the local loop unbundled access system and truly realize the competitive landscape in the access network field.

[8] At present, a technical solution is mentioned in U.S. Patent No. 2,050,175,344, which utilizes wavelength division multiplexing technology in the same optical distribution network (0DN, Optical Distrubtion).

 In Network), users are provided with services from multiple operators, and users are free to choose one of the operators' services.

 [9] In the technical solution mentioned in the patent US20050175344al, 0 instead of colorless, that is, not wavelength-independent, each carrier's 0-upstream and downstream wavelength pairs (one wavelength for uplink, one wavelength for In the down line) is fixed, during the invention, the inventor found that this would lead to the following problems:

[10] Wavelength planning is confusing because operators may lease different wavelength pairs in different cells; [11] The uplink and downlink wavelength pairs of different operators are not uniform. Therefore, when users select different operators, they need to replace 0NU, which brings great trouble to users and will inevitably limit user selection. Degree of freedom

 [12] Because operators may lease different wavelength pairs in different cells, operators must stock multiple types of 0, thus increasing the operator's inventory burden and limiting the operator's service delivery;

 [13] Because terminal manufacturers need to produce multiple types of 0, the total amount of mass production is limited by various types of 0, which is not conducive to the reduction of 0NU cost.

 [14] Summary of the invention

 [15] The embodiments of the present invention are directed to solving the above-mentioned drawbacks in the prior art, and provide a wavelength routing module and a passive optical network system and method using the wavelength routing module, thereby realizing that the optical network unit is colorless, that is, each operation The optical network unit of the quotient can be used universally.

According to an embodiment of the present invention, the present invention provides a passive optical network system, the system comprising at least one optical line termination, an optical distribution network, and at least one optical network unit;

[17] The optical line terminal transmits an optical signal for carrying downlink data through the optical distribution network

And an unmodulated optical signal that does not carry data to the optical network unit.

According to another embodiment of the present invention, the present invention provides a wavelength routing module that can arbitrarily output an input multiple optical signal to an arbitrary output port, and the device includes:

 a demultiplexing device for multiplexing and demultiplexing the received optical signals; and a plurality of branches, one side of the port is respectively connected to the I splitting device, and is used for allocating I

 Merging the received optical signal; and routing means, one side is connected to the port on the other side of the plurality of branches, and the other side is connected to the plurality of second fibers for switching between different output ports to The optical signal is output to any output port.

According to still another embodiment of the present invention, the present invention provides a method for implementing a universal optical network unit in the same passive optical network, the method comprising:

[20] The optical line terminal outputs an optical signal for carrying downlink data, and an unmodulated optical signal for which no data is carried;

[21] combining the two optical signals into one mixed signal, and transmitting the mixed signal to the optical distribution network [22] the optical distribution network transmits the mixed signal to different optical network units through a wavelength routing module;

 [23] the optical network unit receives and demodulates an optical signal carrying downlink data from the optical distribution network, recovers user data, and modulates uplink data of the user into a downlink optical signal that does not carry data, and The optical line terminal is transmitted back to the optical distribution network.

[24] Compared with the prior art, the technical solution in the embodiment of the present invention has at least the following advantages: Through the above-mentioned wavelength routing module and optical network system and method, the present invention realizes universal use of optical network units of various operators. It facilitates the distribution of services by operators.

[25] BRIEF DESCRIPTION OF THE DRAWINGS

 [26] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the drawings used in the embodiments or the prior art description will be briefly described below, and obviously, in the following description The drawings are only some of the embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive labor.

[1] FIG. 1 shows a P0N network structure according to the related art;

2 shows a functional diagram of an optical line terminal in accordance with an embodiment of the present invention;

3 shows a functional diagram of a colorless optical network unit in accordance with an embodiment of the present invention;

4 shows a functional diagram of a wavelength routing module in accordance with an embodiment of the present invention;

5 is a schematic diagram showing the location of the wavelength routing module shown in FIG. 4 in a passive optical network; [32] FIG. 6 illustrates supporting multiple telecommunications carriers in accordance with one embodiment of the present invention. WDM-P0N

 Schematic diagram of the system;

 FIG. 7 illustrates a WDM-P0N supporting multiple protocols in accordance with another embodiment of the present invention.

 Schematic diagram of the system;

[34] Figure

 8 shows a flow diagram of a method of providing multiple optical line terminations in the same passive optical network in accordance with one embodiment of the present invention.

[35] Mode for carrying out the invention

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all An embodiment. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

 2 shows a functional diagram of an optical line terminal in accordance with an embodiment of the present invention. As shown in FIG. 2, the local exchange 200 includes optical line terminals of a plurality of operators (hereinafter referred to as 0LT).

 ). Since each 0LT has the same structure, the following only uses the OLTn of the operator n as an example. The OLTn 210 includes: a switching module 202

 For performing data exchange with the upper-level network; the downlink transmitting module 204 is connected to the switching module 202

For outputting two descending lights having different wavelengths, one of which is downward λ nl

 Used to carry downlink data from the switching module 202, another downstream light λ η2

 It is unmodulated light that does not carry data. Because the unmodulated light has a relatively large loss when passing through the wavelength routing module, it is amplified to be a light source of the colorless optical network unit, and two downstream lights are combined by the coupler 2046. Mixed signal; and uplink receiving and demodulating module 206

 And for receiving an optical signal from the optical distribution network, converting the optical signal into an electrical signal, and demodulating the electrical signal to obtain data sent to the switching module.

3 shows a functional diagram of a colorless optical network unit in accordance with an embodiment of the present invention. As shown in FIG. 3, the optical network unit (hereinafter referred to as 0) receives downlink light from OLTn having wavelengths λ nl and λ _n 2 , respectively, and the downstream light passes through a combined I splitter 302.

 Thereafter, the light of wavelength λ nl carrying the user downlink data is routed to the receive demodulation module 304, and the unmodulated light of wavelength λ η2 is routed to the modulator 306. The photoelectric converter 308 and the demodulator 310 in the receiving demodulation module 304 are completed λ nl

 The photoelectric conversion and data demodulation are sent to the user via the switching module 312. The modulator 306 modulates the user uplink data through the switching module 312 to a wavelength of λ η 2

 The light is transmitted to the optical distribution network via the I splitter 302 and transmitted to the upstream receiving and demodulating module 206 of the OLTn of the operator η. Among them, the modulator 306 of 0 can be selected as RS0A.

(Reflective semiconductor optical amplifier) or injection-locked F-P LD or external modulator.

4 shows a functional diagram of a wavelength routing module in accordance with one embodiment of the present invention. As shown in FIG. 4, the wavelength routing module according to an embodiment of the present invention includes: a first I splitting device 402 For multiplexing and demultiplexing optical signals of different wavelengths; a plurality of second I splitting devices 404 connected to the first combined I

 a demultiplexing device, configured to multiplex and demultiplex the received optical signals from the same operator; the plurality of branches 406, one side of the port is respectively connected to the plurality of second I splitting devices, and is used for allocating I

 Combining the received optical signals; and a fiber crossover matrix 408 as a routing device

 And connected to the port of the other side of the plurality of branches, for switching between different output ports to output the optical signal to any one of the plurality of colorless optical network units.

[40] In this embodiment, the first I splitting device 402 is an array wavelength grating (hereinafter referred to as AWG), and the pair wavelengths are λ 11 , λ 12 ······ λ nl , λ η2

 The light is multiplexed and demultiplexed. The plurality of second I splitting devices are n combined/divided combiners 404. In the downstream direction, the two downstream lights from the operator are combined into one mixed signal, and then a 1:32 splitter 406 is shared and assigned to each. In the upstream direction, the uplink signal from the brancher 406 of 1:32 is the wavelength λ χ 2 (where 1 χ η

 The integer of the optical signal carrying the user's upstream data is separated and routed to the corresponding port of the AWG 402 for transmission to the 0LT through the AWG 402. Wherein n of the 1:32 branching unit 406 are in one-to-one correspondence with each operator (it is also possible to use more than one level of the branching unit to form a 1:32 branch, for example, the first level is a 1:4 branching unit, Level 2 is 1: 8

 Brancher). Wherein, the fiber cross matrix 408

 For the routing device, the jumper is mainly processed according to the operator selected by the user, and the port on the right side of the fiber cross-matrix 408 is connected to the incoming fiber, and the fiber cross-matrix 408

 The port on the left corresponds to each operator's 1 : 32 branch 406 of 32

 The ports are connected. When the user selects different operators, as long as the cable crossover matrix 408 is used for simple and convenient jumper processing, the jumpers can be manual or mechanical, and can even be remotely controlled. .

 Figure 5 shows a schematic diagram of the location of the wavelength routing module of Figure 4 in a passive optical network. As shown in FIG. 5, the far-end node wavelength routing device 502 shown in FIG. 5 is connected to the local exchange 508 via the feeder fiber 504 and to the user terminal 0 via the home fiber 506.

6 shows a WDM-P0N supporting multiple telecommunications carriers in accordance with one embodiment of the present invention. Schematic diagram of the system. As shown in Figure 6, the operator 1 and the operator 2··· the operator n

A medium access control protocol is selected, such as GP0N as the medium access control protocol, and carrier 1 to carrier n have different wavelengths, wherein the uplink and downlink wavelength pairs of the operator 1 are λ 11 and λ 12 , and the operation The upstream and downstream wavelength pairs of quotient 2 are λ 21 and λ 22 , ..., and the upstream and downstream wavelength pairs of the operator η are λ nl and λ _η 2 .

[43] Figure 8

 A flow diagram of a method of providing multiple optical line terminations in the same passive optical network in accordance with one embodiment of the present invention is shown. Combined with Figure 6 and Figure 8 below

 A detailed description of the process of providing multiple optical line terminations in the same passive optical network.

[44] For the downlink signal, as shown in FIG. 8, in step S802, η from different operators 1 to η in the local exchange 600 are taken

 The optical signals of different wavelengths of the optical line terminals are combined into one mixed signal. The mixed signal is then provided to wavelength routing module 602 in step S804. In step S806, the wavelength routing module 602 demultiplexes the mixed signal through the AWG (S8062)

 ) and combine the demultiplexed signals through the combiner (S8064)

 ), and then provided to the corresponding user of each operator (S8066) through the brancher and the fiber cross-matrix. The optical network unit of the client receives and demodulates the optical signal carrying the downlink data from the corresponding operator, and recovers the user data.

[45] For the uplink signal, as shown in Figure 6

 As shown, the optical network unit of the UE modulates the uplink data of the user into the downlink optical signal from the corresponding carrier that does not carry data, and passes through the wavelength routing module 602.

 Combine optical signals from individual users into a mixed signal and transmit it to the local exchange 600

. At the local exchange 600

 The mixed signal is converted into light having different wavelengths by a splitter and transmitted to an uplink receiving and demodulating module of each operator, in which the light is photoelectrically converted and demodulated, and then can be sent to the switching module. The data.

 FIG. 7 illustrates a WDM-P0N supporting multiple protocols in accordance with another embodiment of the present invention.

Schematic diagram of the system. As shown in Figure 7, Carrier 1 adopts GP0N. The medium access control protocol has an uplink and downlink wavelength pair of λ 11 and λ 12 , and the operator η adopts a media access control protocol of BP0N, and the uplink and downlink wavelength pairs are λ nl and λ η 2 .

The operator 2 adopts the EP0N media access control protocol, and its uplink and downlink wavelength pairs are λ 21 and λ 22 , ..., and so on. The system shown in Figure 7 and Figure 6

 The difference between the systems shown is in Figure 7.

 The operator's optical line terminations in the system shown use different protocols. Because the optical line unit adopts different protocols, the wavelength routing module transmits optical signals of different wavelengths to different optical network units according to protocols supported by the optical network unit, and transmits optical signals from different optical network units in opposite directions. Go to the corresponding optical line terminal. Other operations are the same as those shown in Figure 6, and are not repeated.

[47] According to the embodiment of the present invention, the optical network unit of each operator can be versatile, and the service distribution of each operator is facilitated.

 The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim  [1] 1. A passive optical network system, comprising at least one optical line terminal, an optical distribution network, and at least one optical network unit, wherein:  The optical line terminal transmits, by the optical distribution network, an optical signal for carrying downlink data, and an unmodulated optical signal for not carrying data to the optical network unit.  [2] 2. According to claim 1  The passive optical network system, wherein the optical network unit carries uplink data of a user to the unmodulated optical signal that does not carry data by using a modulator, and returns the Optical line terminal.  [3] 3. According to claim 1  The passive optical network system is characterized in that, when the passive optical network system includes multiple optical line terminals or multiple optical network units, any optical network unit selects and multiple lights through the optical distribution network. Any one of the line terminals is connected and transmits optical signals in both directions.  [4] 4. According to claim 3  The passive optical network system is characterized in that: the optical distribution network includes: a wavelength routing module, configured to output an optical signal input from the plurality of optical line terminals to the plurality of optical network units Either, and transmitting optical signals from each of the optical network units to the corresponding optical line terminals in opposite directions, where the optical line terminals, the wavelength routing module, and the optical network unit are connected by optical fibers and perform bidirectional Optical signal transmission.  [5] 5. According to claim 4  The passive optical network system is characterized in that: the wavelength routing module comprises: combining/demultiplexing means for multiplexing and demultiplexing the received optical signals;  a plurality of branches, the ports on the side of the plurality of branches are respectively combined with the  a demultiplexing device is coupled for distributing the I combined received optical signal;  a routing device, one side is connected to a port on the other side of the plurality of splitters, and the other side is connected to a plurality of optical fibers for switching between different output ports to output the optical signal To any of the plurality of optical network units. [6] 6. According to claim 1 The passive optical network system, wherein the optical line terminal comprises:  a downlink transmitting module, configured to output an optical signal for carrying downlink data, and an unmodulated optical signal that does not carry data, and synthesize the two optical signals into a mixed signal;  And an uplink receiving module, configured to receive an optical signal from the optical distribution network, and recover data from the optical signal.  [7] 7. According to claim 6  The passive optical network system is characterized in that: the downlink transmitting module comprises: two light sources for outputting two optical signals having different wavelengths, wherein one light source is used to provide an uplink light source for the optical network unit;  a modulator for modulating downlink data to one of the two optical signals; and a coupler coupled to the modulator for combining the two optical signals into a mixed signal [8] 8. According to claim 6 or 7  The passive optical network system is characterized in that: the downlink transmitting module further includes: an amplifier, configured to amplify at least one of the two optical signals.  [9] 9. According to claim 6  The passive optical network system, wherein the uplink receiving module comprises: a photoelectric converter for converting an optical signal from the optical distribution network into an electrical signal; and a demodulator connected to the And a photoelectric converter, configured to demodulate the electrical signal to recover data.  [10] 10. According to claim 1  The passive optical network system, further characterized by: the optical network unit further comprising: a splitter, connected to the optical distribution network, for separating the optical signal from the optical distribution network into two paths of light a signal, wherein one optical signal carries user data, and the other optical signal does not carry user data; Receiving a demodulation module, coupled to the demultiplexer, for demodulating downlink data from the optical signal carrying user data from the demultiplexer; And a modulator, configured to modulate uplink data into the optical signal that does not carry user data, and send the modulated optical signal to the optical distribution network through the splitter.  [11] 11. A wavelength routing module, comprising:  a combining/demultiplexing device for multiplexing and demultiplexing the received optical signals;  a plurality of branches, the ports on the side of the plurality of branches are respectively combined with the  a demultiplexing device is coupled for distributing the I combined received optical signal;  a routing device, one side is connected to the port on the other side of the plurality of branches, and the other side is connected to the plurality of second fibers for switching between different output ports to The signal is output to any output port.  [12] 12. The wavelength routing module according to claim 11, wherein the combination is  The demultiplexing device is composed of a first combined I splitting device and a plurality of second combined I splitting devices. [13] 13. The wavelength routing module according to claim 12, wherein the first combination  The demultiplexing device is an arrayed waveguide grating. [14] 14. The wavelength routing module according to claim 11, wherein:  The splitter is a 1: N splitter; or  A 1:N splitter consisting of two or more stages of splitter connected in series. [15] 15. According to claims 11 to 14  The wavelength routing module according to any one of the preceding claims, wherein  The routing device is a fiber optic crossover matrix. [16] 16. A method for implementing a general optical network unit in a passive optical network, characterized in that the method comprises the following steps:  The optical line terminal outputs an optical signal for carrying downlink data, and an unmodulated optical signal for which no data is carried;  Combining the two optical signals into one mixed signal, and transmitting the mixed signal to the optical distribution network;  Transmitting, by the optical distribution network, the mixed signal to a different optical network unit through a wavelength routing module; The optical network unit receives and demodulates an optical signal carrying downlink data from the optical distribution network No. recovers the user data, and modulates the user's uplink data into the downlink optical signal that does not carry the data, and transmits the optical data back to the optical line terminal through the optical distribution network.  [17] 17. According to claim 16  The method is characterized in that: the optical distribution network transmitting the mixed signal to different optical network units by using a wavelength routing module specifically includes:  Multiplexing and demultiplexing optical signals of different wavelengths;  Allocating I to combine the received optical signals;  The output port is switched as needed to output the optical signal to the corresponding optical network unit.  [18] 18. According to claim 16  The method is characterized in that, if the plurality of optical line terminals adopt different media access control protocols, the plurality of optical network units are respectively connected to the optical line terminals compatible therewith.  [19] 19. According to claim 16  The method, if the plurality of optical line terminals adopt the same medium access control protocol, respectively connecting the plurality of optical network units to the selected one of the plurality of optical line terminals anyone.  [20] 20. According to claim 16  The method is characterized in that: the plurality of optical line terminals are distinguished by a wavelength division multiplexing method, and each optical line terminal uses a different uplink and downlink wavelength pair.