CN1238612A - Chromatic dispersion compensating method for full-optical communication network using virtual wavelength routing - Google Patents
Chromatic dispersion compensating method for full-optical communication network using virtual wavelength routing Download PDFInfo
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Abstract
A chromatic dispersion compensating method for full-optical communication network using virtual wavelength routing, especially for full-optical MAN and WAN is disclosed. For the full-optical MAN, a frequency spectrum reverser is used at each node and the chromatic dispersion is compensated by said reverser along with special routing method. For full-optical WAN, a frequency spectrum reverser is used at each node and in the center of each linkd and the chromatic dispersion is compensated by said reverser along with special routing method.
Description
The present invention relates to technical field of optical fiber communication, relate in particular to the dispersion compensation method of empty wavelength route in a kind of WDM (wavelength division multiplexing) all optical network.
Human society is to development of information, and optical fiber communication plays a part very important as one of main pillar of modern communications at message area.Chromatic dispersion in the optical fiber is meant when the Optical Fiber Transmission pulse signal, optical fiber and digital communication mode for example, pulse signal broadened phenomenon in transmission course.The CHROMATIC DISPERSION IN FIBER OPTICS phenomenon is totally unfavorable to optical fiber communication.In optical fiber telecommunications system, the optical fiber and digital communications be a series of pulse codes, for example when the light signal of 1.55 μ m transmits in positive dispersion fiber, spectral line medium-high frequency composition transmission rate is higher, its signal energy of carrying will focus on the forward position of pulse gradually, low frequency composition speed is lower, energy will concentrate on the back edge of pulse gradually, thereby appear at the continuous broadening of pulse in the Optical Fiber Transmission process, the phenomenon that adjacent pulse may overlap, promptly produce intersymbol interference, form the error of transmission code, cause the increase that receives the error rate, cause transmission rate to reduce, thereby reduced message capacity, and also limited the transmission range of optical fiber.
Point-to-point dispersion compensation method commonly used at present has:
One, utilizes dispersion compensating fiber.This optical fiber has bigger negative dispersion, can be used for offsetting the positive dispersion of conventional fiber at the 1.55um wave band, and the advantage of this method is the compensation broader bandwidth, is easy to install, and shortcoming is that the compensated fiber that needs is longer, and it is bigger to introduce loss.
Two, adopt the prechirp technology.The thought of prechirp is by to the additional Sine Modulated of light source, makes the frequency of pulse front edge reduce, and the frequency on back edge raises, and has compensated so to a certain extent in the transmission course because the pulse stretching that chromatic dispersion causes.The characteristics of this scheme are to need not transmission and receiving unit are changed, and only need to add an extra Sine Modulated on the transmission laser and get final product.But it requires to adopt the external modulation mode, and the frequency modulation characteristic of laser requires high.
Three, adopt chirped fiber grating.Some gratings of etching can be controlled light reflection therein in optical fiber or waveguide, thereby realize the delay of light signal, play the purpose of compensation of dispersion, squeezed light pulse.The advantage of this compensation method is that volume is little, and the insertion loss is little, and cost is low, can be in the chromatic dispersion on the compensation 500km conventional fiber on the 10Gb/s speed.Its shortcoming is that the compensation bandwidth is narrower.
Four, reversing spectrum method.This method be utilize in the optical fiber or in the semiconductor optical amplifier four-wave mixing effect or difference frequency produce effect in transmission apart from the place with reversing spectrum, make original high frequency composition become the low frequency composition, low frequency composition has originally then become the high frequency composition.Afterwards, light signal passes through the lower semisection Optical Fiber Transmission again, and the then original slow signal component transmission rate after nonlinear change of speed becomes comparatively fast, and vice versa, thereby play the effect of dispersion compensation.For four-wave mixing effect, referring to shown in Figure 1, ω among the figure
sBe the centre frequency of signal, ω
pBe the pump light frequency, ω
cBe the product of four wave mixing, its frequency spectrum and ω
sPhase conjugation, i.e. reversing spectrum.ω is arranged
c=2 ω
p-ω
sAnd for difference frequency produces effect, ω
c=ω
p-ω
s
Increase along with tradition and emerging telecommunication service, the transmission capacity of optical fiber telecommunications system is improved constantly, but traditional electric exchanged form can not adapt to the requirement that message volume increases, the all optical communication technology that is exchanged for core technology with optical transmission, light is arisen at the historic moment, in the network plan of various all optical communications, realize and the practical all-optical network that is based on optical wavelength-division multiplex (WDM, Wavelength DivisionMultiplexing) technology than being easier to.
The WDM all optical network is made up of some wavelength division multiplexing links and optical network unit, realizes the function of transmission, multiplexing, routing, supervision and protection on the light territory.The WDM all optical network has two kinds of routing modes: wavelength route (Wavelength Path) and empty wavelength route (Virtual Wavelength Path).The former sets up a straight-through optical channel and distributes unique wavelength for it between the node that communicates; And the latter after setting up optical channel between the node that communicates, carries out Wavelength Assignment in link ground along optical channel because intermediate node has the ability of wavelength conversion more piecemeal.Because virtual wavelength path can use different wavelength at different links, thereby has improved the utilance of wavelength, reduce the network congestion probability, simplified Network Management and control.
Wavelength conversion technique is the basis of empty wavelength route.Wavelength conversion technique commonly used mainly contains: the cross-gain modulation of a light/electric electro-optical type, based semiconductor image intensifer and crossing phase modulation type, based on four-wave mixing effect type in optical fiber or the semiconductor optical amplifier and light-operated laser type.In various wavelength conversion technique, only based in the optical fiber, in the semiconductor optical amplifier or the four-wave mixing effect in the laser or the difference frequency wavelength conversion technique that produces effect can realize reversing spectrum, for difference frequency produced effect, the scheme of four wave mixing realized and easy practicability easily.Below we unify to represent wavelength shifter based on these two kinds of effects with the reversing spectrum device, represent to realize that with the reversing spectrum effect four-wave mixing effect of reversing spectrum or difference frequency produce various effects such as effect.
The dispersion compensation problem of WDM all optical network is one of key issue of facing of all optical network.Dispersion compensation method in the WDM all optical network that is proposed at present is that point-to-point dispersion compensation technology is applied in the middle of each single optical fiber link.At the reversing spectrum method, this method is the reversing spectrum device to be set with reversing spectrum apart from the place in the transmission of each section link, preceding half section CHROMATIC DISPERSION IN FIBER OPTICS and second half section CHROMATIC DISPERSION IN FIBER OPTICS is offseted, thereby play the effect of dispersion compensation.The shortcoming of this kind scheme is in needs too many wavelength shifter and shortage flexibility.And for full light metropolitan area network,, can cause the increase of cost of investment because network is very complicated;
One of purpose of the present invention is to propose a kind of method that realizes dispersion compensation in the full light metropolitan area network of the WDM that utilizes empty wavelength route that is applicable to; Another object of the present invention is to propose a kind of method that realizes dispersion compensation in the full light wide area network of the WDM that utilizes empty wavelength route that is applicable to.
The objective of the invention is to be achieved through the following technical solutions: the dispersion compensation method in a kind of full light metropolitan area network of WDM that utilizes empty wavelength route, wherein, each node place at this metropolitan area network is provided with the reversing spectrum device, this compensation method includes following steps: (one) utilizes the critical path method (CPM) routing, promptly seek a shortest path, make light signal the fiber lengths of process the shortest, and this path is called the primary election path; (2) analyze the link hop count that optical channel experienced in this primary election path,, then this shortest path is called selected path, directly carry out next step if this primary election path has comprised even number section link; If this primary election path has comprised the odd number link, then one section in this optical channel or several sections links are removed, and, make it intermediate nodes of many experience its routing again, thereby the link that whole passage is experienced is the even number section, and this path is decided to be selected path; (3) selected specific node; (4) in these specific nodes, utilize the reversing spectrum device, when the light signal in this optical channel is carried out wavelength conversion, make this optical signal spectrum counter-rotating; At nonspecific node place, use the wavelength shifter of other type to carry out wavelength conversion.
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node can satisfy following condition first: specific node all nodes for being experienced in this optical channel; And the reversing spectrum device at each specific node place is not all taken fully.
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node can satisfy following condition second: should select the path and split into one or several link group, the quantity of links that each link group is formed and comprised by the adjacent link of even number section is smaller or equal to the total hop count of link in the selected path; With in each link group apart from the place node as described in (three) specific node; And the reversing spectrum device at each specific node place is not all taken fully.
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node also need further to satisfy following condition: take the resulting wavelength of reversing spectrum method less as far as possible.
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node also need further to satisfy following condition: make the utilization rate of the wavelength that each node reversing spectrum process produced approaching as far as possible.
Wherein can also there be a step in dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention between (three) and (four): if can find the specific node that satisfies condition, then carry out (four); If can not find the specific node that satisfies condition, then routing again by the following method: earlier whole passage is divided into roughly equidistant two parts, is called first passage and second channel; Utilize following method to determine specific node to first passage: check whether first passage experiences the node that can also carry out the reversing spectrum wavelength conversion, if through this category node, and the node location second that satisfies condition, then carry out next step; Otherwise, wherein one section link or several sections links are carried out routing again, make it the second that satisfies condition, carry out next step again; If first passage does not experience the node that can carry out the reversing spectrum wavelength conversion, at this moment, the routing again of this first passage makes it through one or more nodes that can carry out the reversing spectrum wavelength conversion, carry out routing again according to aforesaid method again, the requirement of the second that makes it to satisfy condition; Utilize following method to select specific node at wherein second channel: check whether second channel experiences the node that can also carry out the conversion of four wave mixing wavelength, if through this category node, and the node location second that satisfies condition, then can realize dispersion compensation for this half section; If the second that do not satisfy condition, one section or several sections are carried out routing again, make it the second that satisfies condition; If second channel does not experience the node that can carry out the conversion of four wave mixing wavelength, at this moment, the routing again of this second channel makes it through one or more nodes that can carry out the conversion of four wave mixing wavelength, carry out routing again according to aforesaid method again, the requirement of the second that makes it to satisfy condition; Above condition second is: should select the path and split into one or several link group, each link group by the adjacent link composition of even number section and the quantity of links that comprised smaller or equal to the link sum of selecting in the path; With in each link group apart from the place node as specific node; And the reversing spectrum device at each specific node place is not all taken fully.
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention in this metropolitan area network, if the length of adjacent two sections links differs too much, then adds suitable dispersion compensating fiber at that long section and adjusts.
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said reversing spectrum device can be based on the wavelength shifter of four-wave mixing effect, also can be based on the wavelength shifter that difference frequency produces effect.
Second purpose of the present invention is achieved through the following technical solutions: the dispersion compensation method in a kind of full light wide area network of WDM that utilizes empty wavelength route, wherein, each node place at this wide area network is provided with the reversing spectrum device, and be provided with some reversing spectrum devices apart from the place at the middle of this each section of wide area network link, it is characterized in that this method includes following steps: (one) utilizes the critical path method (CPM) routing, promptly seek a shortest path, make light signal the fiber lengths of process the shortest; (2) with this shortest path as selected path, analyze the link hop count that optical channel experienced in this shortest path, experienced at this optical channel under the situation of odd number link, then get wherein one section link, in its link, utilize reversing spectrum to carry out wavelength conversion, utilize dispersive optical element again, to those this section of process links apart from the place, the used wavelength of being made up of even number section link of optical channel separates again, makes it without wavelength shifter; Comprised at this shortest path under the situation of even number section link, directly carried out next step; (3) selected specific node; (4) utilize reversing spectrum device in the specific node, the light signal in this optical channel is carried out wavelength conversion, and make this optical signal spectrum counter-rotating simultaneously; At nonspecific node place, use the wavelength shifter of other type to carry out wavelength conversion.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node satisfies following condition first: specific node all nodes for being experienced in this optical channel; And the reversing spectrum device at each specific node place is not all taken fully.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node satisfies following condition second: should select the path and split into one or several link group, the quantity of links that each link group is formed and comprised by the adjacent link of even number section is smaller or equal to the link sum in the selected path; With in each link group apart from the place node as described in (three) specific node; And the reversing spectrum device at each specific node place is not all taken fully.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, definite also need of wherein said specific node further satisfied following condition: take the wavelength that the reversing spectrum process is produced less as far as possible.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, the determining of wherein said specific node also need further to satisfy following condition: make the utilization rate of the wavelength that each node reversing spectrum process produced approaching as far as possible.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention in this wide area network, if the length of adjacent two sections links differs too much, then adds suitable dispersion compensating fiber at that long section and adjusts.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said reversing spectrum device can be based on the wavelength shifter of four-wave mixing effect, also can be based on the wavelength shifter that difference frequency produces effect.
Along with the continuous progress of wavelength conversion technique, the WDM all optical network will progressively move towards empty wavelength route by the wavelength route.Utilize reversing spectrum to compensate the chromatic dispersion of all optical network, when improving network performance, can significantly reduce hardware investment, reduce link load, simplify the luminous power management of network in conjunction with empty wavelength route.In addition, this scheme is actually a kind of dispersion compensation strategy based on software, and is very flexible in actual applications.For the node that communicates in the network,, when optical channel is set up between node, just can finish the dispersion compensation of optical channel as long as select suitable routing plan.
Below with reference to accompanying drawing, the present invention is described in further detail, wherein
Fig. 1 shows the reversing spectrum that four-wave mixing effect produces;
Fig. 2 shows a WDM all optical network that utilizes empty wavelength route;
Fig. 3 shows an optical channel of being made up of four links.
In the WDM all optical network, whether need the mode of dispersion compensation and dispersion compensation relevant with network size.
For local area network (LAN),, just do not need dispersion compensation because euclidean distance between node pair is a few to tens of kilometers;
For metropolitan area network, nodal pitch is tens to up to a hundred kilometers, adopts the reversing spectrum method can realize the dispersion compensation of optical channel.
Embodiment 1
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node can satisfy following condition first: specific node all nodes for being experienced in this optical channel; And the reversing spectrum device at each specific node place is not all taken fully.
The method of the selected specific node of this kind is more suitable in working as the smaller situation of network size, and at this moment, the interstitial content of network is also fewer, and map network necessary wavelength number is less with it.Adopt the reversing spectrum technology can realize each wavelength of whole nodes is carried out conversion separately.In this case, utilize empty wavelength route, can realize dispersion compensation whole network.Concrete grammar is:
I, at first utilize the critical path method (CPM) routing, to obtain preliminary routing scheme.Critical path method (CPM) can guarantee light signal the fiber lengths of process the shortest, make the chromatic dispersion accumulation and the noise storage minimum of optical channel.
II, analysis link (links) hop count that each optical channel experienced in this routing scheme.If optical channel has experienced even number section link, then this passage can be realized dispersion compensation.If optical channel has experienced the odd number link, then this optical channel routing again.Concrete grammar is: one section of this optical channel or several sections links are removed, and to its routing again, make it intermediate node of many experience, thereby the link that whole passage is experienced is the even number section.As shown in Figure 2: optical channel AD is made up of three sections links through two intermediate nodes of B, C.At this moment, can make it through intermediate node E, thereby the number of links that the overall optical passage is experienced be four the routing again of CD section link, to realize dispersion compensation.In addition, with the routing again of AB section link, make it also can realize the dispersion compensation of optical channel AD through the F node.
III, if adjacent two sections links (as 1 and 2 section, 3 and 4 sections) length differs too much, need to add suitable dispersion compensating fiber and give adjustment at that section of growing.
IV, prevent that optical channel number that some link carries from too much causing " bottleneck " limited phenomenon of whole network, must the Wavelength Assignment scheme of whole network be optimized, make the used number of wavelengths of each section link roughly even, and the link number that makes all optical channels simultaneously and experienced is an even number.
Embodiment 2
Dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node can satisfy following condition second: should select the path and split into one or several link group, the quantity of links that each link group is formed and comprised by the adjacent link of even number section is smaller or equal to the link sum in the selected path; With in each link group apart from the place node as described in (three) specific node; And the reversing spectrum device at each specific node place is not all taken fully.
The method of the selected specific node of this kind is more suitable in working as the very big situation of network size, and at this moment, interstitial content is many in the network, and employed number of wavelengths is also many.Because reversing spectrum efficient is lower, and relevant with the frequency interval of flashlight and pump light, it can realize that the scope of wavelength conversion is limited.At this moment, utilize the method for reversing spectrum can't realize whole wavelength of node are carried out wavelength conversion separately, can only realize the conversion of part wavelength with reversing spectrum, and other needs the wavelength of conversion to adopt other wavelength conversion technique.At this moment, utilize embodiment 1 described method to carry out empty wavelength route again, realize the dispersion compensation of network simultaneously, may cause wavelength resource not enough.
In fact, for an optical channel of forming by the multistage link, utilize the method compensation of dispersion of reversing spectrum to have greater flexibility.Realize the chromatic dispersion of whole passage during it both can be placed on one apart from the reversing spectrum device at place, also can utilize a plurality of reversing spectrum devices, the segmented compensation chromatic dispersion.As Fig. 3: for an optical channel AE who is made up of four sections links, it both can only utilize a reversing spectrum device, was placed on the C point; Also can utilize two reversing spectrum devices, be placed on B, D point respectively and realize.The link number of forming optical channel is many more, and this method is flexible more.As long as guarantee that the total link number is an even number.
If optical channel is made up of n=2k section link, the overall optical passage needs 1 at least so needs k reversing spectrum device can realize dispersion compensation at the most, and the quantity of links that required number, the position of being put and the optical channel of reversing spectrum device comprised has following relation:
1) when k=1, optical channel is made up of 2 sections links, the reversing spectrum device is placed on the passage centre gets final product, and only needs a reversing spectrum device this moment;
2) when k=2, optical channel is made up of 4 sections links, and 2 kinds of methods can be arranged:
A) the reversing spectrum device is placed in the overall optical passage apart from place (i.e. 1/2 place);
B) optical channel that these 4 sections links are formed resolves into two optical channels that each is made up of two sections links, two reversing spectrum devices are placed in the middle of these two optical channels respectively, the chromatic dispersion that each optical channel is experienced is zero, thereby realizes the dispersion compensation of overall optical passage;
3) when k=3, optical channel is made up of 6 sections links, can adopt 3 kinds of methods:
A), only need be placed in the optical channel and locate to get final product apart from (1/2) if only with a reversing spectrum device;
B), two reversing spectrum devices are placed on the middle of these two optical channels respectively get final product apart from the place if, the overall optical passage can be decomposed into two respectively by 2 sections and 4 sections optical channels that link is formed only with two reversing spectrum devices;
C) if adopt three reversing spectrum devices, the overall optical passage can be decomposed into three optical channels of forming by two sections links respectively, these three reversing spectrum devices be placed on the middle of these three optical channels respectively get final product apart from the place;
…
.…
M) when k=m (m≤n/2), optical channel is made up of 2m section link, can adopt m kind method:
A), only need be placed in the optical channel and locate to get final product apart from (1/2) if only with a reversing spectrum device;
B) if only with two reversing spectrum devices, the overall optical passage can be decomposed into two optical channels of forming by even number section link respectively, these two link hop counts that optical channel comprised can equate, also can not wait, as long as guarantee that the number of links summation of two optical channels is 2m.
Two reversing spectrum devices are placed on the middle dispersion compensation that just can realize the overall optical passage apart from the place of these two optical channels respectively;
C) if adopt three reversing spectrum devices, the overall optical passage can be decomposed into three optical channels of being made up of even number section link respectively, these three link hop counts that optical channel comprised can equate, also can not wait.These three reversing spectrum devices are placed on the middle of these three optical channels respectively to get final product apart from the place;
…
I) if adopt i reversing spectrum device, the overall optical passage can be decomposed into i the optical channel of forming by even number section link respectively, three link hop counts that optical channel comprised of this i can equate, also can not wait.This i reversing spectrum device is placed on the middle of this i optical channel respectively to get final product apart from the place;
…
M) if adopt m reversing spectrum device, the overall optical passage can be decomposed into m the optical channel of forming by two sections links respectively, this m reversing spectrum device is placed on the middle of this m optical channel respectively gets final product apart from the place;
Table 1 has reflected the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node satisfies condition under the situation of second, the relation between the number of quantity of links that optical channel comprises and reversing spectrum device, the position of being placed.
Table 1
| Optical channel comprises quantity of links | The number of required reversing spectrum device | The position of reversing spectrum device |
| ???????2 | ???????1 | ??????????????????????1/2 |
| ???????4 | ???????1 | ??????????????????????2/4 |
| ???????2 | ???????????????????(1/4,3/4) | |
| ???????6 | ???????1 | ??????????????????????3/6 |
| ???????2 | (1/6,4/6) or (2/6,5/6) | |
| ???????3 | ?????????????????(1/6,3/6,5/6) | |
| ???????8 | ???????1 | ??????????????????????4/8 |
| ???????2 | (2/8,6/8), (1/8,5/8) or (3/8,7/8) | |
| ???????3 | (1/8,3/8,6), (1/8,4/8,7/8) or (2/8,5/8,7/8) | |
| ???????4 | ????????????????(1/8,3/8,5/8,7/8) | |
| ??????… | ??????… | ????????????????????????… |
The flexibility of the adaptivity of reversing spectrum and segmentation dispersion compensation is under the limited condition of reversing spectrum wavelength conversion technique, and realizing provides possibility to the dispersion compensation of whole network.Concrete grammar is:
At first utilize critical path method (CPM) to carry out initial routing, reexamine this passage and experience several nodes, form, and the intermediate node wavelength utilizes situation by several sections links, i.e. the wavelength that obtains based on reversing spectrum and based on the situation of utilizing of the wavelength of other converter technique, if:
I, this optical channel are made up of even number section link, and the wavelength shifter of the node of process satisfies the relation that is reflected of table 1.Then this passage can be realized dispersion compensation.And at the distribution wavelength, when being optimized, except the principle that will follow used wavelength homogenizing of above-mentioned link and even number link, also to follow following two principle: a, satisfy under the condition of dispersion compensation, take the wavelength that the reversing spectrum process is produced less as far as possible, promptly save the principle of most important resource; B, make the utilization rate of the wavelength that each node reversing spectrum process produced approaching, promptly most important resource utilization is wanted evenly as far as possible.
II, if the condition that optical channel does not satisfy I and proposed, at this moment, can utilize the binary search method: promptly earlier whole passage is divided into roughly equidistant two parts, check again whether preceding half section experienced the node that can also carry out the reversing spectrum wavelength conversion, if through this category node, and node location satisfies the relation of table 1, then can realize dispersion compensation for this half section; If do not satisfy the relation of table 1, one section or several sections are carried out routing again, make it to satisfy condition.If preceding half section is not experienced the node that can carry out the reversing spectrum wavelength conversion, at this moment, this half section link routing again makes it through one or more nodes that can carry out the reversing spectrum wavelength conversion, carry out routing again according to aforesaid method again, make it to satisfy the requirement of table 1.To second half section so processing too, thus the dispersion compensation of realization overall optical passage.Afterwards, carry out Wavelength Assignment and optimization according to above-mentioned optimization principles again.
For wide area network, because spacing is hundreds of even thousands of kilometer between the wide area network node, in routing process,, not only can increase chromatic dispersion how through one section link, also can cause noise storage, have a strong impact on the light signal delivery quality.Therefore, just routing no longer again after utilizing the critical path method (CPM) routing.For the optical channel of being made up of even number section link, link carries out Wavelength Assignment piecemeal; For the passage of forming by the odd number link, get wherein one section link, in its link, utilize reversing spectrum to carry out wavelength conversion, and compensate this link dispersion apart from the place.Utilize dispersive optical element again, those through this section link, are separated by the used wavelength of optical channel that even number section link is formed again, make it without wavelength shifter.Thereby realize the dispersion compensation of network.Have randomness because optical channel is set up, this scheme requires every section link central authorities all to carry out reversing spectrum.But because an optical channel equates by the odd number link or by the probability that even number section link is formed; And because the sparse property of the reversing spectrum device that table 1 embodied, so every section link is only needed middle apart from locating in conjunction with suitable Wavelength allocation method, just can to realize the dispersion compensation to wide area network to subwave progress line frequency spectral inversion wavelength conversion.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node satisfies following condition first: specific node all nodes for being experienced in this optical channel; And the reversing spectrum device at each specific node place is not all taken fully.The method of the selected specific node of this kind is more suitable in working as the smaller situation of network size, and at this moment, the interstitial content of network is also fewer, and map network necessary wavelength number is less with it.Adopt the reversing spectrum technology can realize each wavelength of whole nodes is carried out conversion separately.In this case, utilize empty wavelength route, can realize dispersion compensation whole network.
Embodiment 4
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, wherein said specific node satisfies following condition second: should select the path and split into one or several link group, the quantity of links that each section link group is formed and comprised by the adjacent link of even number section is smaller or equal to the link sum in the selected path; With in each link group apart from the place node as described in (three) specific node; And the reversing spectrum device at each specific node place is not all taken fully.
The method of the selected specific node of this kind is more suitable in working as the very big situation of network size, and at this moment, interstitial content is many in the network, and employed number of wavelengths is also many.At this moment, utilize the method for reversing spectrum can't realize whole wavelength of node are carried out wavelength conversion separately, can only realize the conversion of part wavelength with reversing spectrum, other needs the wavelength of conversion then to adopt other method to carry out wavelength conversion.At this moment, utilize embodiment 3 described methods to carry out empty wavelength route again, realize the dispersion compensation of network simultaneously, may cause wavelength resource not enough.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention, definite also need of wherein said specific node further satisfied following condition: take the wavelength that the reversing spectrum process is produced less as far as possible; Make the utilization rate of the resulting wavelength of each node reversing spectrum approaching as far as possible.
Dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization of the present invention in this wide area network, if the length of adjacent two sections links differs too much, then adds suitable dispersion compensating fiber at that long section and adjusts.
Along with the continuous progress of wavelength conversion technique, the WDM all optical network will progressively move towards empty wavelength route by the wavelength route.Utilize reversing spectrum to compensate the chromatic dispersion of all optical network, when improving network performance, can significantly reduce hardware investment, reduce link load, simplify the luminous power management of network in conjunction with empty wavelength route.In addition, this scheme is actually a kind of dispersion compensation strategy based on software, and is very flexible in actual applications.For the node that communicates in the network,, when optical channel is set up between node, just can finish the dispersion compensation of optical channel as long as select suitable routing plan.
Claims (19)
1, the dispersion compensation method in a kind of full light metropolitan area network of WDM that utilizes empty wavelength route wherein, is provided with the reversing spectrum device at each node place of this metropolitan area network, and this compensation method includes following steps:
(1) utilize the critical path method (CPM) routing, promptly seek a shortest path, make light signal the fiber lengths of process the shortest, and this path is called the primary election path;
(2) analyze the link hop count that optical channel experienced in this primary election path,, then this shortest path is called selected path, directly carry out next step if this primary election path has comprised even number section link; If this primary election path has comprised the odd number link, then one section in this optical channel or several sections links are removed, and, make it intermediate nodes of many experience its routing again, thereby the link that whole passage is experienced is the even number section, and this path is decided to be selected path;
(3) selected specific node;
(4) in these specific nodes, utilize the reversing spectrum device, when the light signal in this optical channel is carried out wavelength conversion, make this optical signal spectrum counter-rotating; At nonspecific node place, use the wavelength shifter of other type to carry out wavelength conversion.
2, the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization as claimed in claim 1, it is characterized in that: wherein said specific node satisfies following condition first:
Specific node all nodes for being experienced in this optical channel; And
The reversing spectrum device at each specific node place is not all taken fully.
3, the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization as claimed in claim 1, it is characterized in that: wherein said specific node satisfies following condition second:
Should select the path and split into one or several link group, the quantity of links that each link group is formed and comprised by the adjacent link of even number section is smaller or equal to the link sum in the selected path; With in each link group apart from the place node as described in (three) specific node; And
The reversing spectrum device at each specific node place is not all taken fully.
4, the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization as claimed in claim 3 is characterized in that: definite also need of wherein said specific node further satisfied following condition: take the resulting wavelength of reversing spectrum method less as far as possible.
5, the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization as claimed in claim 4 is characterized in that: the definite of wherein said specific node also need further satisfy following condition:
Make the utilization rate of the wavelength that each node reversing spectrum process produced approaching as far as possible.
6, as the dispersion compensation method in the full light metropolitan area network of WDM of claim 1,2,3, the empty wavelength route of 4 or 5 described utilizations, it is characterized in that: wherein between (three) and (four), also have a step:
If can find the specific node that satisfies condition, then carry out (four); If can not find the specific node that satisfies condition, then routing again by the following method:
Earlier whole passage is divided into roughly equidistant two parts, is called first passage and second channel;
Utilize following method to determine specific node to first passage: check whether first passage experiences the node that can also carry out the reversing spectrum wavelength conversion, if through this category node, and the node location second that satisfies condition, then carry out next step; Otherwise, wherein one section link or several sections links are carried out routing again, make it the second that satisfies condition, carry out next step again; If first passage does not experience the node that can carry out the reversing spectrum wavelength conversion, at this moment, the routing again of this first passage makes it through one or more nodes that can carry out the reversing spectrum wavelength conversion, carry out routing again according to aforesaid method again, the requirement of the second that makes it to satisfy condition;
Utilize following method to select specific node at wherein second channel: check whether second channel experiences the node that can also carry out the conversion of four wave mixing wavelength, if through this category node, and the node location second that satisfies condition, then can realize dispersion compensation for this half section; If the second that do not satisfy condition, one section or several sections are carried out routing again, make it the second that satisfies condition; If second channel does not experience the node that can carry out the conversion of four wave mixing wavelength, at this moment, the routing again of this second channel makes it through one or more nodes that can carry out the conversion of four wave mixing wavelength, carry out routing again according to aforesaid method again, the requirement of the second that makes it to satisfy condition;
Above condition second is: should select the path and split into one or several link group, each link group by the adjacent link composition of even number section and the quantity of links that comprised smaller or equal to the link sum of selecting in the path; With in each link group apart from the place node as specific node; And the reversing spectrum device at each specific node place is not all taken fully.
7, as the dispersion compensation method in the full light metropolitan area network of WDM of claim 1,2,3, the empty wavelength route of 4 or 5 described utilizations, it is characterized in that: in this metropolitan area network, if the length of adjacent two sections links differs too much, then add suitable dispersion compensating fiber and adjust at that long section.
8, the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization as claimed in claim 6, it is characterized in that: in this metropolitan area network, if the length of adjacent two sections links differs too much, then add suitable dispersion compensating fiber and adjust at that long section.
9, as the dispersion compensation method in the full light metropolitan area network of WDM of claim 1,2,3,4, the empty wavelength route of 5 or 8 described utilizations, it is characterized in that: wherein said reversing spectrum device can be based on the wavelength shifter of four-wave mixing effect, also can be based on the wavelength shifter that difference frequency produces effect.
10, the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization as claimed in claim 6, it is characterized in that: wherein said reversing spectrum device can be based on the wavelength shifter of four-wave mixing effect, also can be based on the wavelength shifter that difference frequency produces effect.
11, the dispersion compensation method in the full light metropolitan area network of the WDM of the empty wavelength route of utilization as claimed in claim 7, it is characterized in that: wherein said reversing spectrum device can be based on the wavelength shifter of four-wave mixing effect, also can be based on the wavelength shifter that difference frequency produces effect.
12, the dispersion compensation method in a kind of full light wide area network of WDM that utilizes empty wavelength route, wherein, each node place at this wide area network is provided with the reversing spectrum device, and is provided with the reversing spectrum device at the middle of this each section of wide area network link apart from the place, it is characterized in that this method includes following steps:
(1) utilize the critical path method (CPM) routing, promptly seek a shortest path, make light signal the fiber lengths of process the shortest;
(2) with this shortest path as selected path, analyze the link hop count that optical channel experienced in this shortest path, experienced at this optical channel under the situation of odd number link, then get wherein one section link, in its link, utilize reversing spectrum to carry out wavelength conversion, utilize dispersive optical element again, to those this section of process links apart from the place, the used wavelength of being made up of even number section link of optical channel separates again, makes it without wavelength shifter; Comprised at this shortest path under the situation of even number section link, directly carried out next step;
(3) selected specific node;
(4) utilize reversing spectrum device in the specific node, the light signal in this optical channel is carried out wavelength conversion, make this optical signal spectrum counter-rotating simultaneously; At nonspecific node place, use the wavelength shifter of other type to carry out wavelength conversion.
13, the dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization as claimed in claim 12, it is characterized in that: wherein said specific node satisfies following condition first:
Specific node all nodes for being experienced in this optical channel; And
The reversing spectrum device at each specific node place is not all taken fully.
14, the dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization as claimed in claim 12, it is characterized in that: wherein said specific node satisfies following condition second:
Should select the path and split into one or several link group, the quantity of links that each link group is formed and comprised by the adjacent link of even number section is smaller or equal to the link sum in the selected path; With in each link group apart from the place node as described in (three) specific node; And
The reversing spectrum device at each specific node place is not all taken fully.
15, the dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization as claimed in claim 14 is characterized in that: the definite of wherein said specific node also need further satisfy following condition:
Take the wavelength that the reversing spectrum process is produced less as far as possible.
16, the dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization as claimed in claim 12 is characterized in that: the definite of wherein said specific node also need further satisfy following condition:
Make the utilization rate of the wavelength that each node reversing spectrum process produced approaching as far as possible.
17, as the dispersion compensation method in the full light wide area network of WDM of claim 12,13,14, the empty wavelength route of 15 or 16 described utilizations, it is characterized in that: in this wide area network, if the length of adjacent two sections links differs too much, then add suitable dispersion compensating fiber and adjust at that long section.
18, as the dispersion compensation method in the full light wide area network of WDM of claim 12,13,14, the empty wavelength route of 15 or 16 described utilizations, it is characterized in that: wherein said reversing spectrum device can be based on the wavelength shifter of four-wave mixing effect, also can be based on the wavelength shifter that difference frequency produces effect.
19, the dispersion compensation method in the full light wide area network of the WDM of the empty wavelength route of utilization as claimed in claim 17, it is characterized in that: wherein said reversing spectrum device can be based on the wavelength shifter of four-wave mixing effect, also can be based on the wavelength shifter that difference frequency produces effect.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN99107830A CN1099776C (en) | 1999-06-02 | 1999-06-02 | Chromatic dispersion compensating method for full-optical communication network using virtual wavelength routing |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN99107830A CN1099776C (en) | 1999-06-02 | 1999-06-02 | Chromatic dispersion compensating method for full-optical communication network using virtual wavelength routing |
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| Publication Number | Publication Date |
|---|---|
| CN1238612A true CN1238612A (en) | 1999-12-15 |
| CN1099776C CN1099776C (en) | 2003-01-22 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8130873B2 (en) | 2004-08-27 | 2012-03-06 | Samsung Electronics Co., Ltd. | Carrier recovery apparatus usable with VSB type receiver and method thereof |
| CN104410456B (en) * | 2014-08-28 | 2017-01-04 | 北京邮电大学 | The hybrid compensation method and device of pattern dependent loss and Polarization Dependent Loss |
| WO2023065816A1 (en) * | 2021-10-20 | 2023-04-27 | 华为技术有限公司 | Communication method, apparatus and system |
-
1999
- 1999-06-02 CN CN99107830A patent/CN1099776C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8130873B2 (en) | 2004-08-27 | 2012-03-06 | Samsung Electronics Co., Ltd. | Carrier recovery apparatus usable with VSB type receiver and method thereof |
| CN104410456B (en) * | 2014-08-28 | 2017-01-04 | 北京邮电大学 | The hybrid compensation method and device of pattern dependent loss and Polarization Dependent Loss |
| WO2023065816A1 (en) * | 2021-10-20 | 2023-04-27 | 华为技术有限公司 | Communication method, apparatus and system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1099776C (en) | 2003-01-22 |
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