CN1254035C - Light wavelength channel protecting method and apparatus for compact WDM system - Google Patents

Abstract

An optical wavelength channel protection method and device for a dense wavelength division multiplexing system related to a multiplexing system, characterized in that: in the dense wavelength division multiplexing system, the multiplexer MUX is connected with an additional multiplexer, The optical signal output by the multiplexer MUX and the output of the backup wavelength tunable optical conversion unit OTU are combined and output by the additional multiplexer, and the additional multiplexer and the corresponding demultiplexer DEMUX use the wavelength tunable optical conversion unit OTU as the system optical wavelength channel Backup protection unit; the demultiplexer DEMUX can be connected with an additional demultiplexer accordingly to receive signals from the additional multiplexer, and the additional multiplexer and the additional demultiplexer use the wavelength tunable optical conversion unit OTU as the system light The wavelength channel backup protection unit; the invention has high utilization rate of wavelength resources of the system.

Description

Optical wavelength channel protection method and device for dense wavelength division multiplexing system

technical field

The invention relates to a multiplexing system, in particular to an optical wavelength channel protection method and device for a dense wavelength division multiplexing system.

Background technique

Currently, there are two common optical wavelength channel protection modes in dense wavelength division multiplexing DWDM systems: n:m and n+m optical wavelength protection modes.

For the n:m working mode, as shown in Figure 1, the n backup optical wavelength channels transmit low-priority services when the system is not faulty, but when one or more of the m optical wavelength channels fails , the low-priority services of the backup channel are discarded, and the services of the faulty channel are switched to the backup channel for transmission. The n:m optical wavelength channel protection method essentially only transfers the faulty channel, and does not really perform a complete system performance Fault protection, so the n:m optical channel protection mode on the DWDM backbone network is rarely used, and this protection mode is more used in circuit-level protection.

In the n:m optical wavelength channel protection mode, n backup wavelength channels also have a certain priority, that is, when a working channel fails, the service of the backup channel with the lowest priority will be discarded, and the service signal of the faulty unit will pass through n *m The cross matrix is switched to the backup channel for transmission, and the priority of the backup channel is updated at the same time; when another working channel fails, the system will check the service priority of the remaining n-1 backup wavelength channels, Decide which backup wavelength channel to switch the faulty service to. After querying, the system will control the n*m switching matrix, and switch the business of the faulty channel to the lowest priority backup wavelength channel for transmission. Of course, this wavelength channel has the lowest priority Level services will be discarded, and at the same time the service priority identifiers of the backup channels will be updated, and so on, and the backup protection of n backup wavelength channels to m working channel services will be gradually realized.

For the n+m optical wavelength channel protection mode, as shown in Figure 2, during normal operation, m working wavelength channels carry services, while n backup wavelength channel units are in the hot backup state, and each backup wavelength channel is for a The hot backup protection is carried out corresponding to the working wavelength channel, that is, the backup wavelength channel and the working wavelength channel carry the same service. Because it is a hot backup, the most common form of n+m protection is 1+1. When a protected working wavelength channel fails, the receiving end will compare the service quality of the working wavelength channel and the corresponding backup wavelength channel, and select the service carried by the backup wavelength channel to complete the protection function. If another working wavelength channel fails at this time, the receiving end will also compare the services carried by the working wavelength channel with the services carried by the backup wavelength channel to decide whether to switch; The transmission mission when a failure occurs, but the backup wavelength channel must also carry the service of the corresponding working wavelength channel when there is no failure. The service of which working wavelength channel is carried by the backup wavelength channel can be specified by configuring the n*m matrix.

However, whether it is n:m or n+m optical wavelength channel protection mode, it is required to have n backup wavelength channels as backup. In other words, all wavelength channels are reserved as backup channels to realize the protection of working wavelength channels Backup protection, in this way, the wavelength resources of the system must be occupied, so that the limited wavelength resources of the system cannot be fully utilized.

Contents of the invention

The object of the present invention is to provide an optical wavelength channel protection method and device for a dense wavelength division multiplexing system with high utilization rate of system wavelength resources.

The technical solution adopted in the present invention is: a method for protecting an optical wavelength channel of a dense wavelength division multiplexing system, characterized in that: when the working wavelength channel of the dense wavelength division multiplexing system fails, the system control The unit closes the corresponding sending and receiving optical conversion units at both ends of the wavelength channel, and sets the corresponding optical conversion unit to a fault state; selects a backup wavelength tunable optical conversion unit in a standby state as a temporary bearing unit of the faulty channel; the system Adjust the output wavelength of the backup wavelength tunable optical conversion unit to the carrier wavelength of the faulty channel, switch the service of the faulty channel to the backup wavelength tunable optical conversion unit for transmission; after switching, the system modifies the work of the backup wavelength tunable optical conversion unit The status changes from standby to work.

After the faulty wavelength channel is repaired, the system shuts down the backup wavelength tunable optical conversion unit and activates the optical conversion unit of the working channel, and the service line is switched back to the original working state.

An additional multiplexer is added to the sending end system, and the optical signal output by the working optical conversion unit at the sending end and the output of the backup wavelength tunable optical conversion unit are combined by the additional multiplexer and connected to the transmission link.

The receiving end system can add an additional wave splitter, and an adjustable filter device is installed in the additional wave splitter. The optical signal output by the transmission link enters the wave splitter through the additional wave splitter, and then is connected to each working Optical conversion unit; when the business of the faulty channel is switched to the backup wavelength tunable optical conversion unit for transmission, the center frequency of the adjustable filter device corresponding to the backup wavelength tunable optical conversion unit is switched from the working frequency band to the center of the faulty channel wavelength; when the faulty channel is repaired, modify the center frequency of the adjustable filtering device to outside the operating frequency band.

An optical switching matrix can also be added to the receiving end system to replace the above-mentioned additional wave splitter, and the optical signal output by the transmission link passes through the wave splitter and then connected to each working optical conversion unit.

The present invention also proposes an optical wavelength channel protection device for a dense wavelength division multiplexing system, including a transmitting-end multiplexer and a receiving-end demultiplexer, and each of the transmitting end and the receiving end is provided with a plurality of optical conversion units, And the input side of the working optical conversion unit at the sending end and the output side of the working optical conversion unit at the receiving end are respectively connected with an optical switching matrix for line switching, which is characterized in that: an additional wave combiner is also included, and the sending end multiplexes The multiplexer is connected to an additional multiplexer; multiple backup wavelength tunable optical conversion units are connected to the optical switching matrix, and the optical signal output by the multiplexer and the optical signal output by the backup wavelength tunable optical conversion unit are passed through the additional The multiplexer is combined and connected to the transmission link; the optical signal of the transmission link enters the optical conversion unit through the receiving end demultiplexer, and multiple backup wavelength-tunable optical conversion units are connected to the optical switching matrix .

The wave splitter can be connected with additional wave splitters accordingly, and an adjustable filter device is arranged in the additional wave splitter, and the optical signal output by the transmission link enters the wave splitter through the additional wave splitter, and then is connected to each Working optical conversion unit.

The demultiplexer can also be connected with an optical switching matrix correspondingly, instead of the above additional demultiplexer, and the optical signal output by the transmission link passes through the demultiplexer, and then is connected to each working optical conversion unit.

The beneficial effects of the present invention are: in the present invention, by adding an additional multiplexer, the wavelength-tunable optical conversion unit is used as the system optical wavelength channel backup protection unit to achieve the purpose of wavelength channel backup protection without occupying system optical wavelength resources, The actual wavelength utilization rate of the system is 100%, but the backup performance of the system is not reduced. Therefore, the present invention has a high utilization rate of the wavelength resource of the system, and more fully utilizes the limited wavelength resource of the system.

Description of drawings

FIG. 1 is a schematic structural diagram of an n:m optical channel protection mode in the prior art;

FIG. 2 is a schematic structural diagram of an n+m optical channel protection mode in the prior art;

Fig. 3 is the structural representation of embodiment 1;

Fig. 4 is a schematic structural diagram of embodiment 2.

Detailed ways

Below according to accompanying drawing and embodiment the present invention will be described in further detail:

Example 1:

According to Fig. 3, the present invention comprises the multiplexer (MUX) of transmitting end system and the demultiplexer (DEMUX) of receiving end system, and described transmitting end and receiving end are respectively provided with a plurality of optical conversion units (OTU) as working OTU , the OTU is a fixed wavelength, and each of the transmitting end and the receiving end has a k*(m+n) switching matrix for line switching. The multiplexer MUX is connected to an additional multiplexer, and the additional multiplexer can be a coupler. A wavelength-insensitive multiplexer, the additional multiplexer and the corresponding multiplexer MUX are connected to the wavelength tunable optical conversion unit OTU as the system optical wavelength channel backup protection unit, and the backup optical conversion unit OTU at the input end has a wavelength tunable optical conversion unit. Tuning and sending modules, additional multiplexers can be attached with wavelength tunable filters, such as acousto-optic tunable filters, electro-optic tunable filters, etc. The optical signal output by the system MUX at the sending end and the output of the backup wavelength tunable optical conversion unit OTU are combined and output by an additional multiplexer, and then connected to the transmission link. A k*(m+n) switching matrix is added at the receiving end, the k*(m+n) switching matrix is connected to the DEMUX and the backup OTU unit, the optical signal output by the transmission link passes through the DEMUX, and then connected to each working OTU unit.

As shown in Figure 3, under normal working conditions, the original n+m channels of the system are completely used for working channels, and the n+m channels shown here are for the channels in Figure 1 and Figure 2 In other words, k backup optical conversion units OTU as backup protection units are in the standby state, and the backup optical conversion unit OTU at the sending end has no output. After the optical signal is transmitted to the receiving end, it enters each working optical conversion unit through the demultiplexer DEMUX OTU, complete reception.

When the working wavelength channel of DWDM system fails:

A. The system control unit closes the corresponding sending and receiving optical conversion unit OTU at both ends of the wavelength channel, and sets the OTU state of the optical conversion unit as failure to be repaired;

B. Query the working state of the backup optical conversion unit OTU at the sending end, and the first backup optical conversion unit OTU that is inquired to be in the standby state is used as the temporary bearing unit of the faulty channel;

C. After the query is completed, the system sends an instruction to the backup optical conversion unit OTU, adjusts its output wavelength to the carrier wavelength of the faulty channel, and sends an instruction to three k*(m+n) switching matrices to switch the service of the faulty channel To the backup optical conversion unit OTU for switching and transmission, and complete the business process of the backup optical conversion unit OTU unit carrying the faulty channel;

D. After switching, the system modifies the working state of the backup optical conversion unit OTU from standby to working.

If another working channel also fails at this time, the system control unit also first closes the optical conversion unit OTU corresponding to the faulty channel at the sending end and the receiving end, and queries the first backup optical conversion unit OTU in the standby state. The switching transmission of the faulty channel service is completed through the process similar to the above.

After the faulty wavelength channel is repaired, the system control unit regularly detects the status of the optical conversion unit OTU of the working channel. Once the optical conversion unit OTU of the original wavelength channel is found to be in the ready state, the system shuts down the backup optical conversion unit OTU and starts the working channel at the same time The optical conversion unit OTU, the line is switched back to the original working state, and the state of each optical conversion unit OTU is restored to the initial state.

Example 2:

According to Fig. 4, the present invention comprises the multiplexer MUX of transmitting end and the demultiplexer DEMUX of receiving end, and described transmitting end and receiving end are respectively provided with a plurality of optical conversion units OTU as working OTU, and this OTU is fixed wavelength, and transmitting The end and the receiving end each have a switching matrix for line switching. The MUX at the sending end is connected to an additional multiplexer. The additional multiplexer can be a wavelength-insensitive multiplexer such as a coupler. The additional multiplexer and the additional demultiplexer are respectively connected to the corresponding wavelength tunable optical conversion unit OTU as the system optical wavelength channel backup protection unit. The wavelength tunable optical conversion unit OTU at the input end has a wavelength tunable transmission module. A wavelength tunable filter is arranged in the wave splitter. A wavelength tunable filter can be attached to the additional combiner, such as an acousto-optic tunable filter, an electro-optic tunable filter, a coupler, etc.

The optical signal output by the MUX at the sending end and the output of the backup wavelength tunable optical conversion unit OTU are combined and output by an additional multiplexer, connected to the transmission link, and entered into the demultiplexer by an additional demultiplexer at the receiving end, and converted by a wavelength tunable optical The unit OTU is used as the system optical wavelength channel backup protection unit, and the wavelength tunable filter in the additional demultiplexer separates the corresponding backup wavelength channel when the working wavelength channel fails.

As shown in Figure 4, under normal working conditions, the original n+m channels of the system are completely used for working channels, and the n+m channels shown here are for the channels in Figure 1 and Figure 2 In other words, k backup optical conversion units OTU as backup protection units are in the standby state, and the backup optical conversion units OTU at the sending end have no output. After the optical signal is transmitted to the receiving end, the system does not perform any control on the additional demultiplexer at this time. , the additional demultiplexer does not perform any processing on the optical signal at this time, the optical signal is directly transmitted to the demultiplexer DEMUX, and finally enters each working optical conversion unit OTU to complete the reception.

When the working wavelength channel of DWDM system fails:

A. The system control unit closes the corresponding sending and receiving optical conversion unit OTU at both ends of the wavelength channel, and sets the OTU state of the optical conversion unit as failure to be repaired;

B. Query the working state of the backup optical conversion unit OTU at the sending end, and the first backup optical conversion unit OTU that is inquired to be in the standby state is used as the temporary bearing unit of the faulty channel;

C. After the query is completed, the system sends an instruction to the backup optical conversion unit OTU, adjusts its output wavelength to the carrier wavelength of the faulty channel, and switches the center frequency of the adjustable filter device at the receiving end corresponding to the backup optical conversion unit OTU from out-of-band to The central wavelength of the faulty channel is adjusted to the carrier wavelength of the faulty channel, and the service of the faulty channel is switched to the backup optical conversion unit OTU through the corresponding k*(m+n) switching matrix for switching and transmission. At this time, the business of the faulty channel All are switched to the backup optical conversion unit OTU for transmission, but the center frequency of the carrier carrying the faulty channel business on the line has not changed, thus completing the backup optical conversion unit OTU unit carrying the faulty channel business process;

D. After switching, the system modifies the working state of the backup optical conversion unit OTU from standby to working.

If there are other working channels that continue to fail at this time, as described above, the system will first close the faulty channel, and at the same time inquire about the working status of the backup optical conversion unit OTU, and select the corresponding backup optical conversion unit OTU as a substitute for the faulty channel. Then issue instructions to the backup optical conversion unit OTU, switching matrix and additional wave splitter to complete the corresponding service switching work, and so on for subsequent failures of other channels.

When the faulty wavelength channel is repaired, the system control unit regularly detects the status of the optical conversion unit OTU of the working channel. Once the optical conversion unit OTU of the original wavelength channel is found to be in the ready state, the system shuts down the backup optical conversion unit OTU, and additional demultiplexing The center frequency of the adjustable filter device corresponding to the filter is adjusted to the outside of the working frequency band, and the optical conversion unit OTU of the working channel is started at the same time, the line is switched back to the original working state, and the state of each optical conversion unit OTU is restored to the initial state.

In the above two embodiments, in fact, the working channel can be divided into multiple channel groups, and then additional multiplexers with corresponding numbers of groups are provided, and the backup optical conversion unit OTU in each additional multiplexer is connected to the The optical wavelength channel protection is performed on the working channel, thus forming the group protection of the entire working channel, its principle, structure and control method are basically the same as those described in the previous embodiment 1 and embodiment 2, and will not be repeated here.

In practical applications, the wavelength tunable optical conversion unit OTU is connected to the variable optical attenuator VOA, and the effect of gain flatness is achieved by using the variable optical attenuator VOA in the backup optical conversion unit OTU.

Claims (11)

1, a kind of optical wavelength channel protection method that is used for dense wavelength division multiplexing system is characterized in that:

When the operation wavelength passage of described dense wavelength division multiplexing system breaks down:

A, system control unit are closed the transmission and the reception optical conversion unit of this wavelength channel transmitting terminal and receiving terminal correspondence, and it is malfunction that this corresponding optical conversion unit is set;

B, select the temporary transient load bearing unit of a backup wavelength-tunable optics converting unit that is ready as faulty channel;

The output wavelength that C, system adjust this backup wavelength-tunable optics converting unit is the carrier wavelength of faulty channel, the business of faulty channel is switched to backup wavelength-tunable optics converting unit transmit;

D, switch after, the operating state of backup wavelength-tunable optics converting unit is revised by the work of awaiting orders by system.

2, the optical wavelength channel protection method that is used for dense wavelength division multiplexing system according to claim 1; it is characterized in that: after the described wavelength channel that breaks down is repaired; system closing backup wavelength-tunable optics converting unit starts the optical conversion unit of working channel simultaneously, and service circuit is switched back former operating state.

3, the optical wavelength channel protection method that is used for dense wavelength division multiplexing system according to claim 1; it is characterized in that: transmitting terminal increases the attached wave multiplexer that adds; the light signal and the output of described backup wavelength-tunable optics converting unit of the described work optical conversion unit output of transmitting terminal merge through additional wave multiplexer, insert transmission link.

4, the optical wavelength channel protection method that is used for dense wavelength division multiplexing system according to claim 3, it is characterized in that: receiving terminal system can increase the attached channel-splitting filter that adds, be provided with adjustable filter in the additional channel-splitting filter, the light signal of described transmission link output enters channel-splitting filter through described additional channel-splitting filter, is linked into the optical conversion unit of respectively working again;

When the business with faulty channel switches to backup wavelength-tunable optics converting unit when transmitting, the centre frequency of the adjustable filter of this backup wavelength-tunable optics converting unit correspondence switches to faulty channel centre wavelength outward by the operating frequency band;

After faulty channel was repaired, the centre frequency of revising described adjustable filter was to the operating frequency band.

5, the optical wavelength channel protection method that is used for dense wavelength division multiplexing system according to claim 3; it is characterized in that: receiving terminal system can increase light of company and switch matrix; the light signal of described transmission link output is linked into the optical conversion unit of respectively working again through channel-splitting filter.

6, the optical wavelength channel protection method that is used for dense wavelength division multiplexing system according to claim 1 and 2; it is characterized in that further comprising: earlier working channel is divided into a plurality of channel group; set up the additional wave multiplexer of respective sets number again in the transmitting terminal system; backup optical conversion unit OTU in each additional wave multiplexer carries out the optical wavelength path protection to the working channel in the respective channel group, forms the packet protection to whole service aisle.

7, a kind of optical wavelength path protection device that is used for dense wavelength division multiplexing system of realizing claim 1, comprise transmitting terminal wave multiplexer and receiving terminal channel-splitting filter, described transmitting terminal and receiving terminal respectively are provided with a plurality of optical conversion units, and respectively connect a light that is used for line switching at the outlet side of the work optical conversion unit of the input side of the work optical conversion unit of transmitting terminal and receiving terminal and switch matrix, it is characterized in that: also comprise additional wave multiplexer, described transmitting terminal wave multiplexer connects additional wave multiplexer; A plurality of backup wavelength-tunable optics converting units are switched matrix with described light and are connected, and the light signal of the light signal of described wave multiplexer output and the output of described backup wavelength-tunable optics converting unit merges through additional wave multiplexer, is linked into transmission link; The light signal of described transmission link enters into optical conversion unit through the receiving terminal channel-splitting filter, and a plurality of backup wavelength-tunable optics converting units are switched matrix with described light and are connected.

8, the optical wavelength path protection device that is used for dense wavelength division multiplexing system according to claim 7; it is characterized in that: described channel-splitting filter can correspondingly increase the attached channel-splitting filter that adds; be provided with adjustable filter in the additional channel-splitting filter; the light signal of described transmission link output enters channel-splitting filter through additional channel-splitting filter, is linked into the optical conversion unit of respectively working again.

9, the optical wavelength path protection device that is used for dense wavelength division multiplexing system according to claim 7; it is characterized in that: described channel-splitting filter can correspondingly increase company's light and switch matrix; the light signal of described transmission link output is linked into the optical conversion unit of respectively working again through channel-splitting filter.

10, according to claim 7, the 8 or 9 described optical wavelength path protection devices that are used for dense wavelength division multiplexing system, it is characterized in that: in the described additional wave multiplexer adjustable filter can be set.

11, according to claim 7, the 8 or 9 described optical wavelength path protection devices that are used for dense wavelength division multiplexing system, it is characterized in that: described additional wave multiplexer can be a coupler.