CA2186149A1 - Optical amplifier combiner arrangement and method for upstream transmission realised thereby - Google Patents
Optical amplifier combiner arrangement and method for upstream transmission realised therebyInfo
- Publication number
- CA2186149A1 CA2186149A1 CA002186149A CA2186149A CA2186149A1 CA 2186149 A1 CA2186149 A1 CA 2186149A1 CA 002186149 A CA002186149 A CA 002186149A CA 2186149 A CA2186149 A CA 2186149A CA 2186149 A1 CA2186149 A1 CA 2186149A1
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- CA
- Canada
- Prior art keywords
- optical
- ini
- information signal
- arrangement
- branch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/27—Arrangements for networking
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/27—Arrangements for networking
- H04B10/272—Star-type networks or tree-type networks
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
- H04B10/293—Signal power control
- H04B10/2933—Signal power control considering the whole optical path
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0062—Network aspects
- H04Q11/0067—Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
Abstract
The optical amplifier combiner arrangement is used in a tree-like optical network (APON) consisting of the cascade connection of dedicated branches of the arrangement and of a common branch. The arrangement is coupled between a plurality of optical network users and on optical line terminator, viathe dedicated branches and the common branch respectively. The network enables upstream transmission of information signals from the optical network users to the optical line terminator. The optical amplifier combiner arrangementincludes for each branch of the dedicated branches:
- an optical amplifier to amplify an information signal with a gain value and tothereby generate an amplified information signal with a predetermined power level, - an optical switch on/off coupled between the optical amplifier and an optical combiner to pass the amplified information signal when the information signal ispresent and to interrupt the branch when the information signal is not present The optical combiner is included in the arrangement to combine all amplified information signals according to a multiple access technique and to thereby generate an outgoing optical signal for application to the optical line terminator.
- an optical amplifier to amplify an information signal with a gain value and tothereby generate an amplified information signal with a predetermined power level, - an optical switch on/off coupled between the optical amplifier and an optical combiner to pass the amplified information signal when the information signal ispresent and to interrupt the branch when the information signal is not present The optical combiner is included in the arrangement to combine all amplified information signals according to a multiple access technique and to thereby generate an outgoing optical signal for application to the optical line terminator.
Description
21861~9 OPTICAL AMPLIFlER COMBINER ARRANGENlENT AND METHOD FOR
UPSTREAM TRQNSMlS~lON REALISED THEREBY
1 he preSQnt invention relates to an optical an,plifier co"lbiner arrangemont as described in the pream~le of claim 1 and a method for upstream lrans"~ission realised thereby, usecl in a tree-like optical network toperform upstroam transmission as descri~ed in the prea"~le of claim 10.
Such an optical a~ptifier combiner and such a method are already known in the art, e.g. ~rom the article 'Ne~work Design for t~?e Information Superh~ghwa~ written by P.W. France, J H. Mackenzie and others, published 10 by The European Instit~te for Communicat~ons and Networks in lhe book ProcHedings volume 1 Papers on Br~adband Superhighway wherein p~ssive op(ical networks are described which use such a combiner and which realiz~
such a melhod. These passive optical network systems are dovelopped to meet the emerging superhighway requiremenls such as the capability to provlde both existing narrowband ~nd new broadband distributive and interactive services to serve both husiness and residential customers.
However serving business and residential customers requires a much higher splitting factor than provided by these known networks. A main problem in the realizatlon of high splitt~ng factors occurs during the upstream 20 transrnission. Indeed, due to this high splitting Factor a high powerbudg~t must b~ ovelcome. The demanding optioal powerbudget for transmissi~n is supported by the implementation ~f optical amplifiers in the deoqcated branches However, due ~o the multiple access tec~,.,iq~Je used at the Optical combiner which col"bi~,es the inror"-ation signals, all these optical an~pliriers contribute to an a~cumulalion of ASE (amplified spontaneous e",issio") noi~e, even when the optical amplifier does not carry an information signal and as a resull thereof, the ASE noise can reach such an amplitude that the (,~.,s!"ittedsi~nals are degraded.
An object of the present inven~ion is to providn an optical amplifier 30 cornbiner arrangement and a method such as the above known on~s but which ~re slJIted for networks with high splitting factors, i.e. which ensure thflt the transmitted signals can not be degraded by the relative~y high ~SE noise.
Accordin~ t~ the invention, tllis object is achieved by means of th~
optical amplifier combiner arrangement as described in claim 1, realizing the method as descnbed in claim 10.
Indeed, since the branches whlch carry no information signal, ar~
interrupted with the c~ptical switches onloff, ~hese branches can not contributeto the accumulation of ASE noise at the opUcal cornbiner A possit~l~ implementation of the control of the optical amplifier cor~biner 10 alrangement is that for each branch th~ ga~n value of the optical amplifier and the optical switch onlc~ff are controlled respectively by means ot a first and secon~ ~lectrical control signal. This implementation is described in claim 2.
The first electrical control signal is composed of gain setting data and gain tunin~ data This gain tuning data is inlrocil~ced to comp~nsate deviations of th~3 optical amplification due tu e.g. sensitiveness with r~sF)ect to temperature and tlme of the optical amplifier.
An ~dditlonal characteristic f~ature of the present invenlion is that, as described in claim 3, the switch onJoff is controlled by means of th~ second el~ctrical control signal which results f~om the detection of the presence of an20 informatlon signal on the according branch.
Another way of contro~ling the switch onloff is described in claim ~, and is based on the use, in an optical net.~ork uslng for upstream transmission a time division multiple access techniquQ, ~ the detection of special grant information ou~ of downstream irlrvlrl~atiOn The use of such speci~l grant informatinn to realize time divisivn multiple access is well known in the art, e g.
from the publisched European patent appl~cafion wif~l publkafion r7~lmber EP-O
544 9,5 wherein a time sl~ management system Is described which allows upstream transmission. The stream of station identities us~d therein is sinnilarto th~ ~pecial ~rant information. In the impl~r"en~alion of claim 4 the second
UPSTREAM TRQNSMlS~lON REALISED THEREBY
1 he preSQnt invention relates to an optical an,plifier co"lbiner arrangemont as described in the pream~le of claim 1 and a method for upstream lrans"~ission realised thereby, usecl in a tree-like optical network toperform upstroam transmission as descri~ed in the prea"~le of claim 10.
Such an optical a~ptifier combiner and such a method are already known in the art, e.g. ~rom the article 'Ne~work Design for t~?e Information Superh~ghwa~ written by P.W. France, J H. Mackenzie and others, published 10 by The European Instit~te for Communicat~ons and Networks in lhe book ProcHedings volume 1 Papers on Br~adband Superhighway wherein p~ssive op(ical networks are described which use such a combiner and which realiz~
such a melhod. These passive optical network systems are dovelopped to meet the emerging superhighway requiremenls such as the capability to provlde both existing narrowband ~nd new broadband distributive and interactive services to serve both husiness and residential customers.
However serving business and residential customers requires a much higher splitting factor than provided by these known networks. A main problem in the realizatlon of high splitt~ng factors occurs during the upstream 20 transrnission. Indeed, due to this high splitting Factor a high powerbudg~t must b~ ovelcome. The demanding optioal powerbudget for transmissi~n is supported by the implementation ~f optical amplifiers in the deoqcated branches However, due ~o the multiple access tec~,.,iq~Je used at the Optical combiner which col"bi~,es the inror"-ation signals, all these optical an~pliriers contribute to an a~cumulalion of ASE (amplified spontaneous e",issio") noi~e, even when the optical amplifier does not carry an information signal and as a resull thereof, the ASE noise can reach such an amplitude that the (,~.,s!"ittedsi~nals are degraded.
An object of the present inven~ion is to providn an optical amplifier 30 cornbiner arrangement and a method such as the above known on~s but which ~re slJIted for networks with high splitting factors, i.e. which ensure thflt the transmitted signals can not be degraded by the relative~y high ~SE noise.
Accordin~ t~ the invention, tllis object is achieved by means of th~
optical amplifier combiner arrangement as described in claim 1, realizing the method as descnbed in claim 10.
Indeed, since the branches whlch carry no information signal, ar~
interrupted with the c~ptical switches onloff, ~hese branches can not contributeto the accumulation of ASE noise at the opUcal cornbiner A possit~l~ implementation of the control of the optical amplifier cor~biner 10 alrangement is that for each branch th~ ga~n value of the optical amplifier and the optical switch onlc~ff are controlled respectively by means ot a first and secon~ ~lectrical control signal. This implementation is described in claim 2.
The first electrical control signal is composed of gain setting data and gain tunin~ data This gain tuning data is inlrocil~ced to comp~nsate deviations of th~3 optical amplification due tu e.g. sensitiveness with r~sF)ect to temperature and tlme of the optical amplifier.
An ~dditlonal characteristic f~ature of the present invenlion is that, as described in claim 3, the switch onJoff is controlled by means of th~ second el~ctrical control signal which results f~om the detection of the presence of an20 informatlon signal on the according branch.
Another way of contro~ling the switch onloff is described in claim ~, and is based on the use, in an optical net.~ork uslng for upstream transmission a time division multiple access techniquQ, ~ the detection of special grant information ou~ of downstream irlrvlrl~atiOn The use of such speci~l grant informatinn to realize time divisivn multiple access is well known in the art, e g.
from the publisched European patent appl~cafion wif~l publkafion r7~lmber EP-O
544 9,5 wherein a time sl~ management system Is described which allows upstream transmission. The stream of station identities us~d therein is sinnilarto th~ ~pecial ~rant information. In the impl~r"en~alion of claim 4 the second
- 2~8~9 elec~rical control signal is deterrnined by the detection of special granl informalior1 in downstream ir~ tiorl.
Yet a further ch~racteristic feature of the present invention is th~t, as described in claim 5, the gain settin~ data i~ d~ten~,:aed by measurir~g the power of the information signal.
Another characteristic feature of the present invention is th~, as described in claim 6, the gain tuning data is determined by measurin~ the power of ~he amplified inrorn~alion signal .
An al~orn~tive way to d~tsrmine the gain tuning data is descri~ed in 10 claim 7 and consists in using a memory means ~o ",e,l,ori~e lhe value Of the l~st measured powor of an amplified signal and to use this value to contml ~he gain tuning data ~or a followlng tran~mitted Information signal.
Another way to determine the gain tun~ng data is described in claim 8, which introduces a power level unit lo measure the power level o~ the outgoing optical signal to determine the gain tuning data for the b,~nches carrying an informaUon signal. In thls way, Instead of measuring the pow~r for each dedicated branch, only one pvwer rn~asurement has to be p~,fb""ed wliich is less power consumins~
Still another character,stic feature is the integration of the dptical ~0 combiner with all optical switches on/off In one optical switch, as descri~ed in claim 9.
~ he above mentloned and oth~r objects and ~eatures o~ the invention will become moro apparent and the invention itself will be best understo¢~ by ref~rrin~ to the following description o~ an embodimen1 taken in conju~ction with th~ accompanying dr~wing First, the optical amplifier c~mbiner arrangen,ent OAS will be explained by me~ns of a functional deseril tion of the blocks shown in the flgure. Based on this de~cription. impleme, It~tion of the ~unetional blocks in the figure ~ill ~e obvious to a person skille~ in the art.
- 21~ 9 The optical amplifier combiner arran~ement OAS~is used in a tr~e-lilce optical network consisting of the cascade conne~lion of dedicated branches B1, B2, ..., Bi, Bn and of Ihe optical amplifier combiner a"~"~",ent OAS and of a common branch. The optic~l amplifier combiner arrangement OAS is coupled b~tween a plurality of optlcal network ~Jsers ONU1, ONU2, , ONUi, , ON~Jn and an optical line tetminalor OLT via the above mentioned dedicated branches and cornrnon branch respectively.
The optical amplifier co",~i. ,er arrangement OAS includes for e~ch branch e g Bi, of the dedicated branchQs B1 B~, ., Bi, . ., Bn two basic p~rts .10 - an optical ~n)~l-fier OAi coupled to the respectivs nctwotk user ONUi of the optical net~ork u~ers ONU1, ONU2. , ONUi, .., ONUn; and - an optical switch onloff SW ON/OFFi coupled between the optical an~plifier OAi and an optlcai combiner O~
The optical combiner OS is coupled between all optical switch~s onloff SW ONIOFF1, SW ON/OFF2. . ., SW ONlOFFi ... SW ONlOFFn which are simular to the optical switch on/off SW ON/OFFi and the optical line t~rminator OLT
the optical amplifier con,bil1er arran~ement OAS enables upsltre~m transmission in the optical network o~ informotion signals IN1, IN2, , ll~li, , 20 INn fro~ the optical network users ONU1, ONU2, , ONUi, ..., ONUn to the optlcal llne termlnator (:)L I .
The principle working of the optical amplifier combiner OAS will be explained in the following para~raph with respect to a signal INi ~lansn~itled over a branch ~i, the working with respect to the other branches being idenlical .
the optical ampli~ier OAi amplifies INi wi~h a ~ain value Gi (not shown) and generates thereby an amplif~cd inf~rmation signal A-lNi ~Ath a predeterrnined power level - 21~ 9 The optical switch on/off SW ONlOFFi passes the amplified info",.ation signal A-lNi when it is present~ but inlerrupts the branch Bi whsn the amptifiedinformation signal A-lNi is not present.
The optlcal combiner OS combines all amplified information signals A-IN1 A-IN2, ., A-lNi, .., ~-INn simular lo Ihe amplifi~d in~r~ tion si~nal A-lNi according to a multiple access technique and genorates thereby an outl3oing optical signal OUT for a,~plication to the optical line terrninator OLT
In this ernbodiment ~he working o~ the optical amplifier OAi and the optical switch on/of~ SW ON/OFFi of each branch Bi is controlled by means of 10 control means CTRLi. The control m~ans CTRLi is co~pled to the OAi ar~d the optical switch onloff SW ONlOFFi and controls:
- ~h~ ~ain value Gi by means of a first Cl~ l ical control signal C~-AI
comp~secl of gain setting data GSi (not shown) and gain tuning ~iata G~i (not shown), and - the switch onloff SW ONtOFFi by means of a second electrical control signal CTRL-Bi.
The gain setting data GSi the gain luning data GTi and the second electrical conlrol signal CTRL-Bi can be determined in different ways. A few particulàr implcmentations to determine them are described in a functional way 20 in the following par~ylaphs, but they are not shown in the figure to avoid overloading thereof To dctermine the second electrical control signal CTRL-Bi, fo~ each branch Bi, the control means CT~Li further includ~s power detectic~n me~ns which via an optical tap draws off the illfo""~ sign~l INi a small po~4er part.
Th~ power detection means determines whether the information s~nal INi is present o~ is not present and determines the second ele~trica~ control 8i~nal CTRL-Bi as a result thereof.
To deternline the gain setting data GSI, ~or each branch Bi, the control means CTRLi Further includes power measuring means. The same optic~l tap - 218~1~9 as above is use~ and the power rr~easuring means meas~r~s the po~ver of the nformation signal INi and determines the gain setting data GSi based the~reon.
It has to be noted t ere that ~o en~ure that tho power measurin~ rneans has enou~h time to fulfil its function an optical del~y line (not sllown) is coupled botween the optical tap and the optical amplifler (:)Ai. The optical delay line delays the inf~r",dlion signal INi ~Intill the optical ampiifier pAi is adjusted.
To detotmine the gain tuning data GTi for each branch Bi tho control means CTlRLi furth~r includes addilional power measuring means. Via an 10 additional optical tap coupled between the optical switch on/off SW O~ FFi and ~he optical combiner OS a small power part is drawn off the amplified inf~r",dlion signal A-INI and the a~ditional power measuring means measures the pownr of the amplified information signal A-lNi and detormines the ~ain tuning data GTi based lhereon.
Furthermore it is notod th~t although for the optical amplifier OAi an erbium doped fibre am~lifier is used semiconductor optical amplifiers ar~ vety good candidates to use in this implementalion because o~ their low swit~h-on tirne. It is also remarked that these s~rniconductor optical amplifiers can be used to integrate the functions o~ the oplical amplifier OAi and of the optical ~?() switch on/off ~;W ON/C)FFi An alternative implementation to detennine the second electrical c~ntrol signal CT~L-Bi is realised for ~ptical networks ~Ivhere the optical combiner OS
combines the amplified infe""dtion si~nals ~-IN1 A-IN2 ... A~ i ... A-lNn according to a time division multiple access techniqu~. For such an aptical n~twork the optical arnplifier combiner al,ange",ent OAS includes ~n optical network terminator NTOAM (not shown) for performing operation and maintenance func~ions. T'l~ NTOAM is coupled tO Ule optical line terrnlnator OLT by means of also an additional optical tap, and to the control r~eans CTP<Li. The addi~ional optical tap draws off the do~",sl,ea"~ signals which are 3u sent from th~ optical line ler,n;nator OLT to the optical network terminators 21~
ONU1, ONU2, ., ONVi, .... ONUn a small po~ ,all and pro~.rides this power fraction to the optical network terminator NTOAM which captures special grant i.~f~"",~tion out of these downstream signals. Accor~i"sJ to the remark in the introduction, th~ use ~f special grant information to realize time di~rision mu~tiple ~ccess is well known in the art. With this special ~rant information, the optical network terminator NTOAM knows ~xactly when an information signal INi will be sont by an optical network user ONUi and when the i,~ né1tion si~nal INi wi~l b~ applled to the optical amplifier OAi. The special grant information is appliecl to the control means CTRLi which is now able to 10 dotermine whether the information signal INi will be present or willl not be present within a predetermined time intQrval and determines the sec~nd electrical control signal CTRL-Bi as a result ~hereof.
Still ano~h~r alternative implementation to d~(~r",i,-~ the gain tuning data GTi, fur each blanch Bi, is realised by inclu~ing in th~ control means CTRLi, additional t~ measuring means to measure the power o~ an amplified Inlormation ~ignal A-lNi. also memory means to mernorize the value of the measured power of the amplified si~nal This value is us~d to determin~ the gain tunin~ data GTi for a following transmitted info",1ation signal INi.
Finally. it h~s to ~e remarked that an alternative way to determin~ the 20 gain tuning data G~i, for each ~ranch Bi, is realized with the implementation of one power level unit. The power level unit, included in the opt~cal amplifier combiner arrangement OAS, is co~Jpled between a control output of the optical combiner OS and the control means CTRLi asso~idted with each branch Si.
rhe power leYel unit measures the power l~vel of 1he outgoing optical ~i~nal OUT and provides the result thereof by means o~ electrical power level d~ta t~
thQ control means CTR~i. Th~ control means CTRLi is now able to d~ler,-,ine the g~in tuning data GTi if an information signal is pr~sent.
It has to be remarked thal the optical combiner OS and all optic~l swilctles onloff SW OI~J/OFF 1, SW ON/OFF2, ..., SW ONlOFFi. ..., SW
- 218~1~9 ON/OF~n simular to the optical switch on/off SW ON/OF~i can be integrate~ in one oplical switc~l.
Sir1ce it is obvious for a p~3rson skilled in the art how lo realize the above alternative implernenta ions based on their fundional description these realizations are not clescribed in further details.
It has als~ to be remarked that the outgoing optical signal OUT of Ihe present optical amplifier combiner ~rran~ement OAS has to be anlplified in order to overco",e a longe distance to the optical line terminator OLT. With an effici~nt workin~ of the diHerent optical amplifiers OA1 OA2~ . OAi ..., OAn 10 simular to the optical amplifier OAi in the optical amplifier ~ombiner arr~ngement OAS and an appropriate access ~utocol that assures continuous u,~sl,ean~ trans",ission for the outgoing signal OUT the outgoing optical ~i~nalO~Jr has no longer a bursty character like the infu,l,-blion ~ignals IN1 IN2 ...INi INn ~1ave In this way a fast gain setting optical amplifier Is no longer required for the amplifica~ion of thc optical out~oing ~igna~ OUT and a st~ndardoptical amplifiers can be us~d While the principles of the inventien have been d~scribed abo~Je in connection with specific apparatus it is to be clearly understood t~a~ Ihis description is made only by way of example and not as a limitation on the 20 scope of the invention.
Yet a further ch~racteristic feature of the present invention is th~t, as described in claim 5, the gain settin~ data i~ d~ten~,:aed by measurir~g the power of the information signal.
Another characteristic feature of the present invention is th~, as described in claim 6, the gain tuning data is determined by measurin~ the power of ~he amplified inrorn~alion signal .
An al~orn~tive way to d~tsrmine the gain tuning data is descri~ed in 10 claim 7 and consists in using a memory means ~o ",e,l,ori~e lhe value Of the l~st measured powor of an amplified signal and to use this value to contml ~he gain tuning data ~or a followlng tran~mitted Information signal.
Another way to determine the gain tun~ng data is described in claim 8, which introduces a power level unit lo measure the power level o~ the outgoing optical signal to determine the gain tuning data for the b,~nches carrying an informaUon signal. In thls way, Instead of measuring the pow~r for each dedicated branch, only one pvwer rn~asurement has to be p~,fb""ed wliich is less power consumins~
Still another character,stic feature is the integration of the dptical ~0 combiner with all optical switches on/off In one optical switch, as descri~ed in claim 9.
~ he above mentloned and oth~r objects and ~eatures o~ the invention will become moro apparent and the invention itself will be best understo¢~ by ref~rrin~ to the following description o~ an embodimen1 taken in conju~ction with th~ accompanying dr~wing First, the optical amplifier c~mbiner arrangen,ent OAS will be explained by me~ns of a functional deseril tion of the blocks shown in the flgure. Based on this de~cription. impleme, It~tion of the ~unetional blocks in the figure ~ill ~e obvious to a person skille~ in the art.
- 21~ 9 The optical amplifier combiner arran~ement OAS~is used in a tr~e-lilce optical network consisting of the cascade conne~lion of dedicated branches B1, B2, ..., Bi, Bn and of Ihe optical amplifier combiner a"~"~",ent OAS and of a common branch. The optic~l amplifier combiner arrangement OAS is coupled b~tween a plurality of optlcal network ~Jsers ONU1, ONU2, , ONUi, , ON~Jn and an optical line tetminalor OLT via the above mentioned dedicated branches and cornrnon branch respectively.
The optical amplifier co",~i. ,er arrangement OAS includes for e~ch branch e g Bi, of the dedicated branchQs B1 B~, ., Bi, . ., Bn two basic p~rts .10 - an optical ~n)~l-fier OAi coupled to the respectivs nctwotk user ONUi of the optical net~ork u~ers ONU1, ONU2. , ONUi, .., ONUn; and - an optical switch onloff SW ON/OFFi coupled between the optical an~plifier OAi and an optlcai combiner O~
The optical combiner OS is coupled between all optical switch~s onloff SW ONIOFF1, SW ON/OFF2. . ., SW ONlOFFi ... SW ONlOFFn which are simular to the optical switch on/off SW ON/OFFi and the optical line t~rminator OLT
the optical amplifier con,bil1er arran~ement OAS enables upsltre~m transmission in the optical network o~ informotion signals IN1, IN2, , ll~li, , 20 INn fro~ the optical network users ONU1, ONU2, , ONUi, ..., ONUn to the optlcal llne termlnator (:)L I .
The principle working of the optical amplifier combiner OAS will be explained in the following para~raph with respect to a signal INi ~lansn~itled over a branch ~i, the working with respect to the other branches being idenlical .
the optical ampli~ier OAi amplifies INi wi~h a ~ain value Gi (not shown) and generates thereby an amplif~cd inf~rmation signal A-lNi ~Ath a predeterrnined power level - 21~ 9 The optical switch on/off SW ONlOFFi passes the amplified info",.ation signal A-lNi when it is present~ but inlerrupts the branch Bi whsn the amptifiedinformation signal A-lNi is not present.
The optlcal combiner OS combines all amplified information signals A-IN1 A-IN2, ., A-lNi, .., ~-INn simular lo Ihe amplifi~d in~r~ tion si~nal A-lNi according to a multiple access technique and genorates thereby an outl3oing optical signal OUT for a,~plication to the optical line terrninator OLT
In this ernbodiment ~he working o~ the optical amplifier OAi and the optical switch on/of~ SW ON/OFFi of each branch Bi is controlled by means of 10 control means CTRLi. The control m~ans CTRLi is co~pled to the OAi ar~d the optical switch onloff SW ONlOFFi and controls:
- ~h~ ~ain value Gi by means of a first Cl~ l ical control signal C~-AI
comp~secl of gain setting data GSi (not shown) and gain tuning ~iata G~i (not shown), and - the switch onloff SW ONtOFFi by means of a second electrical control signal CTRL-Bi.
The gain setting data GSi the gain luning data GTi and the second electrical conlrol signal CTRL-Bi can be determined in different ways. A few particulàr implcmentations to determine them are described in a functional way 20 in the following par~ylaphs, but they are not shown in the figure to avoid overloading thereof To dctermine the second electrical control signal CTRL-Bi, fo~ each branch Bi, the control means CT~Li further includ~s power detectic~n me~ns which via an optical tap draws off the illfo""~ sign~l INi a small po~4er part.
Th~ power detection means determines whether the information s~nal INi is present o~ is not present and determines the second ele~trica~ control 8i~nal CTRL-Bi as a result thereof.
To deternline the gain setting data GSI, ~or each branch Bi, the control means CTRLi Further includes power measuring means. The same optic~l tap - 218~1~9 as above is use~ and the power rr~easuring means meas~r~s the po~ver of the nformation signal INi and determines the gain setting data GSi based the~reon.
It has to be noted t ere that ~o en~ure that tho power measurin~ rneans has enou~h time to fulfil its function an optical del~y line (not sllown) is coupled botween the optical tap and the optical amplifler (:)Ai. The optical delay line delays the inf~r",dlion signal INi ~Intill the optical ampiifier pAi is adjusted.
To detotmine the gain tuning data GTi for each branch Bi tho control means CTlRLi furth~r includes addilional power measuring means. Via an 10 additional optical tap coupled between the optical switch on/off SW O~ FFi and ~he optical combiner OS a small power part is drawn off the amplified inf~r",dlion signal A-INI and the a~ditional power measuring means measures the pownr of the amplified information signal A-lNi and detormines the ~ain tuning data GTi based lhereon.
Furthermore it is notod th~t although for the optical amplifier OAi an erbium doped fibre am~lifier is used semiconductor optical amplifiers ar~ vety good candidates to use in this implementalion because o~ their low swit~h-on tirne. It is also remarked that these s~rniconductor optical amplifiers can be used to integrate the functions o~ the oplical amplifier OAi and of the optical ~?() switch on/off ~;W ON/C)FFi An alternative implementation to detennine the second electrical c~ntrol signal CT~L-Bi is realised for ~ptical networks ~Ivhere the optical combiner OS
combines the amplified infe""dtion si~nals ~-IN1 A-IN2 ... A~ i ... A-lNn according to a time division multiple access techniqu~. For such an aptical n~twork the optical arnplifier combiner al,ange",ent OAS includes ~n optical network terminator NTOAM (not shown) for performing operation and maintenance func~ions. T'l~ NTOAM is coupled tO Ule optical line terrnlnator OLT by means of also an additional optical tap, and to the control r~eans CTP<Li. The addi~ional optical tap draws off the do~",sl,ea"~ signals which are 3u sent from th~ optical line ler,n;nator OLT to the optical network terminators 21~
ONU1, ONU2, ., ONVi, .... ONUn a small po~ ,all and pro~.rides this power fraction to the optical network terminator NTOAM which captures special grant i.~f~"",~tion out of these downstream signals. Accor~i"sJ to the remark in the introduction, th~ use ~f special grant information to realize time di~rision mu~tiple ~ccess is well known in the art. With this special ~rant information, the optical network terminator NTOAM knows ~xactly when an information signal INi will be sont by an optical network user ONUi and when the i,~ né1tion si~nal INi wi~l b~ applled to the optical amplifier OAi. The special grant information is appliecl to the control means CTRLi which is now able to 10 dotermine whether the information signal INi will be present or willl not be present within a predetermined time intQrval and determines the sec~nd electrical control signal CTRL-Bi as a result ~hereof.
Still ano~h~r alternative implementation to d~(~r",i,-~ the gain tuning data GTi, fur each blanch Bi, is realised by inclu~ing in th~ control means CTRLi, additional t~ measuring means to measure the power o~ an amplified Inlormation ~ignal A-lNi. also memory means to mernorize the value of the measured power of the amplified si~nal This value is us~d to determin~ the gain tunin~ data GTi for a following transmitted info",1ation signal INi.
Finally. it h~s to ~e remarked that an alternative way to determin~ the 20 gain tuning data G~i, for each ~ranch Bi, is realized with the implementation of one power level unit. The power level unit, included in the opt~cal amplifier combiner arrangement OAS, is co~Jpled between a control output of the optical combiner OS and the control means CTRLi asso~idted with each branch Si.
rhe power leYel unit measures the power l~vel of 1he outgoing optical ~i~nal OUT and provides the result thereof by means o~ electrical power level d~ta t~
thQ control means CTR~i. Th~ control means CTRLi is now able to d~ler,-,ine the g~in tuning data GTi if an information signal is pr~sent.
It has to be remarked thal the optical combiner OS and all optic~l swilctles onloff SW OI~J/OFF 1, SW ON/OFF2, ..., SW ONlOFFi. ..., SW
- 218~1~9 ON/OF~n simular to the optical switch on/off SW ON/OF~i can be integrate~ in one oplical switc~l.
Sir1ce it is obvious for a p~3rson skilled in the art how lo realize the above alternative implernenta ions based on their fundional description these realizations are not clescribed in further details.
It has als~ to be remarked that the outgoing optical signal OUT of Ihe present optical amplifier combiner ~rran~ement OAS has to be anlplified in order to overco",e a longe distance to the optical line terminator OLT. With an effici~nt workin~ of the diHerent optical amplifiers OA1 OA2~ . OAi ..., OAn 10 simular to the optical amplifier OAi in the optical amplifier ~ombiner arr~ngement OAS and an appropriate access ~utocol that assures continuous u,~sl,ean~ trans",ission for the outgoing signal OUT the outgoing optical ~i~nalO~Jr has no longer a bursty character like the infu,l,-blion ~ignals IN1 IN2 ...INi INn ~1ave In this way a fast gain setting optical amplifier Is no longer required for the amplifica~ion of thc optical out~oing ~igna~ OUT and a st~ndardoptical amplifiers can be us~d While the principles of the inventien have been d~scribed abo~Je in connection with specific apparatus it is to be clearly understood t~a~ Ihis description is made only by way of example and not as a limitation on the 20 scope of the invention.
Claims (10)
1 Optical amplifier combiner arrangement (OAS) in a tree-like optical network (APON) consisting of the cascade connection of dedicated branches (B1, B2,, Bi, ..., Bn), of said arrangement (OAS) and of a common branch, said arrangement being coupled between a plurality of optical network users (ONU1 ONU2, ..., ONUi, ..., ONUn) and an optical line terminator (OLT) via said dedicated branches and said common branch respectively, said network enabling upstream transmission of information signals (IN1, IN2, . ., INi, ...,INn) from said optical network users (ONU1, ONU2, ..., ONUi, ., ONUn) to said optical line terminator (OLT), characterized in that said optical amplifier combiner arrangement (OAS) includes for each branch (Bi) of said dedicated branches (B1,B2, ..., Bi, ..., Bn):
- an optical amplifier (OAi) to amplify a respective one (INi) of said information signals (IN1, IN2, ..., INi, ..., ,INn) transmitted over said branch (Bi), with a gain value (Gi) and to thereby generate an amplified information signal (A-INi) with a predetermined power level;
- an optical switch on/off (SW ON/OFFi) coupled between said optical amplifier (OAi) and an optical combiner (OS) which is included in said arrangement to combine all amplified information signals (A-IN1, A-IN2, ..., A-INi, ..., A-INn)simular to said amplified information signal (A-INi) according to a multiple access technique and to thereby generate an outgoing optical signal (OUT) for application to said optical line terminator (OLT), said optical switch on/off (SW
ON/OFFi) being provided to pass said amplified information signal (A-INi) when it is present and to interrupt said branch (Bi) when it is not present.
- an optical amplifier (OAi) to amplify a respective one (INi) of said information signals (IN1, IN2, ..., INi, ..., ,INn) transmitted over said branch (Bi), with a gain value (Gi) and to thereby generate an amplified information signal (A-INi) with a predetermined power level;
- an optical switch on/off (SW ON/OFFi) coupled between said optical amplifier (OAi) and an optical combiner (OS) which is included in said arrangement to combine all amplified information signals (A-IN1, A-IN2, ..., A-INi, ..., A-INn)simular to said amplified information signal (A-INi) according to a multiple access technique and to thereby generate an outgoing optical signal (OUT) for application to said optical line terminator (OLT), said optical switch on/off (SW
ON/OFFi) being provided to pass said amplified information signal (A-INi) when it is present and to interrupt said branch (Bi) when it is not present.
2 Optical amplifier combiner arrangement (OAS) according to claim 1 characterized in that said arrangement (OAS) also includes for each said branch (Bi) a control means (CTRLi) coupled to said optical amplifier (OAi) and to said optical switch on/off (SW ON/OFFi) said control means (CTRLi) being adapted to control said gain value (Gi) by means of a first electrical control signal (CTRL-Ai) composed of gain setting data (GSi) and gain tuning data (GTi), and to control said switch on/off (SW ON/OFFi) by means of a second electrical control signal (CTRL-Bi).
3. Optical amplifier combiner arrangement (OAS) according to claim 2 characterized in, that for each said branch (Bi), said control means (CTRLi) further includes power detection means provided to detect whether said one information signal (INi) is present or is not present and to determine said second electrical control signal (CTRL-BI) as a result thereof
4. Optical amplifier combiner arrangement (OAs) according to claim 2 characterised in that said optical combiner (OS) is provided to combine said amplified information signals (A-IN1, A-IN2, ., A-lNi, , A-lNn) according to a time division multiple access (TDMA) technique, and in that said arrangement (OAS) also includes an optical network terminator (NTOAM) for performing operation and maintenance functions and which is coupled to said optical line terminator (OLT) and said control means (CTRLi), said optical network terminator (NTOAM) being included to capture special grant information out of downstream signals sent from said optical line terminator (OLT) to said optical network users (ONU1, ONU2 , ONUi, ... ONUn) and to apply said special grant information to said control means (CTRLi) to thereby enable said control means (CTRLi) to determine whether said information signal (INi) will be present or not present within a predetermined time interval and to determine said second electrical control signal (CTRL-Bi) as a result thereof.
5 Optical amplifier combiner arrangement (OAS) according to claim 2 characterized in that for each said branch (Bi) said control means (CTRLi).
further includes power measuring means provided to measure the power of said one information signal (INi) and to determine said gain setting data (GSi) based thereon.
further includes power measuring means provided to measure the power of said one information signal (INi) and to determine said gain setting data (GSi) based thereon.
6 Optical amplifier combiner arrangement (OAS) according to claim 2 characterized in that. for each said branch (Bi), said control means (CTRLi) further includes power measuring means provided to measure the power of said amplified information signal (A-INi) and to determine said gain tuning data(GTi) based thereon.
Optical amplifier combiner arrangement (OAS) according to claim 2 characterized in that, for each said branch (Bi), said control means (CTRLi) further includes power measuring means provided to measure the power of said amplified information signal (A-lNi) and to provide a value of measured power of said amplified information signal (A-lNi) and further includes memory means to memorize said value, said value being used to determine said gain tuning data (GTi) for a following transmitted information signal (INi).
8 Optical amplifier combiner arrangement (OAS) according to claim 2 characterized in that said arrangement (OAS) also includes a power level unit (P-opt) coupled between a control output of said optical combiner (OS) and said control means (CTRLi) associated with each branch (Bi), said power level unit being (P-opt) provided to measure the power level of said outgoing optical signal (OUT) and to supply as a result thereof electrical power level data (P-OUT) to said control means (CTRLi) to thereby enable said control means (CTRLi) to determine said gain tuning data (GTi) when said information signal (A-INi) is present.
9 Optical amplifier combiner arrangement (OAS) according to claim 1 characterized in that said optical combiner (OS) and all optical switches on/off(SW ON/OFF1, SW ON/OFF2 ..., SW ON/OFFi, , SW ON/OFFn) simular to said optical switch on/off (SW ON/OFFi) are integrated in an optical switch (OSW).
10. A method used in a tree-like optical network (APON) to perform upstream transmission of information signals (IN1. IN2 .., INi, ..., INn) from apluralily of optical network users (ONU1, ONU2 . ., ONUi, , ONUn) to an optical line terminator (OLT) via dedicated branches (B1, B2, . Bi, .., Bn) and a common branch respectively, characterized in that said method for each one (INi) of said information signals (IN1, IN2, ., INi, ..., INn) comprises the steps of;
a amplifying said information signal (INi) and thereby generating an amplified information signal (A-lNi);
b passing said amplified information signal (A-lNi) when said information signal (INi) is present and interrupting said branch (Bi) when said information signal (INi) is not present;
and further includes the step of:
c combining all amplified information signals (A-IN1, A-IN, .., A-lNi, ..., A-lNn) simular to said amplified information signal (A-lNi) according to a multiple access technique thereby generating an outgoing optical signal (OUT) which is transmitted to said optical line terminator (OLT).
a amplifying said information signal (INi) and thereby generating an amplified information signal (A-lNi);
b passing said amplified information signal (A-lNi) when said information signal (INi) is present and interrupting said branch (Bi) when said information signal (INi) is not present;
and further includes the step of:
c combining all amplified information signals (A-IN1, A-IN, .., A-lNi, ..., A-lNn) simular to said amplified information signal (A-lNi) according to a multiple access technique thereby generating an outgoing optical signal (OUT) which is transmitted to said optical line terminator (OLT).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP95202553.4 | 1995-09-21 | ||
| EP95202553A EP0765045B1 (en) | 1995-09-21 | 1995-09-21 | Arrangement for amplifying and combining optical signals, and method for upstream transmission realised therewith |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2186149A1 true CA2186149A1 (en) | 1997-03-22 |
Family
ID=8220648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002186149A Abandoned CA2186149A1 (en) | 1995-09-21 | 1996-09-20 | Optical amplifier combiner arrangement and method for upstream transmission realised thereby |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5754319A (en) |
| EP (1) | EP0765045B1 (en) |
| JP (1) | JP3842349B2 (en) |
| AU (1) | AU714781B2 (en) |
| CA (1) | CA2186149A1 (en) |
| DE (1) | DE69524751T2 (en) |
| ES (1) | ES2167399T3 (en) |
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| EP0989694B1 (en) * | 1998-09-23 | 2004-05-19 | Alcatel | Method for determining a switching moment |
| DE69932499T2 (en) | 1999-03-17 | 2007-03-08 | Alcatel | Method for centrally controlling a line termination in a tree-like network |
| US6693033B2 (en) | 2000-02-10 | 2004-02-17 | Motorola, Inc. | Method of removing an amorphous oxide from a monocrystalline surface |
| US20020063932A1 (en) * | 2000-05-30 | 2002-05-30 | Brian Unitt | Multiple access system for communications network |
| AU2001264987A1 (en) * | 2000-06-30 | 2002-01-14 | Motorola, Inc., A Corporation Of The State Of Delware | Hybrid semiconductor structure and device |
| US6590236B1 (en) | 2000-07-24 | 2003-07-08 | Motorola, Inc. | Semiconductor structure for use with high-frequency signals |
| US6555946B1 (en) | 2000-07-24 | 2003-04-29 | Motorola, Inc. | Acoustic wave device and process for forming the same |
| US6493497B1 (en) | 2000-09-26 | 2002-12-10 | Motorola, Inc. | Electro-optic structure and process for fabricating same |
| US6638838B1 (en) | 2000-10-02 | 2003-10-28 | Motorola, Inc. | Semiconductor structure including a partially annealed layer and method of forming the same |
| US6501121B1 (en) | 2000-11-15 | 2002-12-31 | Motorola, Inc. | Semiconductor structure |
| US6559471B2 (en) | 2000-12-08 | 2003-05-06 | Motorola, Inc. | Quantum well infrared photodetector and method for fabricating same |
| US6673646B2 (en) | 2001-02-28 | 2004-01-06 | Motorola, Inc. | Growth of compound semiconductor structures on patterned oxide films and process for fabricating same |
| US6709989B2 (en) | 2001-06-21 | 2004-03-23 | Motorola, Inc. | Method for fabricating a semiconductor structure including a metal oxide interface with silicon |
| EP1271825A1 (en) * | 2001-06-25 | 2003-01-02 | Lucent Technologies Inc. | Method and system for multiplexed optical information transport |
| US6531740B2 (en) | 2001-07-17 | 2003-03-11 | Motorola, Inc. | Integrated impedance matching and stability network |
| US6646293B2 (en) | 2001-07-18 | 2003-11-11 | Motorola, Inc. | Structure for fabricating high electron mobility transistors utilizing the formation of complaint substrates |
| US6498358B1 (en) * | 2001-07-20 | 2002-12-24 | Motorola, Inc. | Structure and method for fabricating an electro-optic system having an electrochromic diffraction grating |
| US6693298B2 (en) | 2001-07-20 | 2004-02-17 | Motorola, Inc. | Structure and method for fabricating epitaxial semiconductor on insulator (SOI) structures and devices utilizing the formation of a compliant substrate for materials used to form same |
| US6667196B2 (en) | 2001-07-25 | 2003-12-23 | Motorola, Inc. | Method for real-time monitoring and controlling perovskite oxide film growth and semiconductor structure formed using the method |
| US6589856B2 (en) | 2001-08-06 | 2003-07-08 | Motorola, Inc. | Method and apparatus for controlling anti-phase domains in semiconductor structures and devices |
| US6639249B2 (en) | 2001-08-06 | 2003-10-28 | Motorola, Inc. | Structure and method for fabrication for a solid-state lighting device |
| US6673667B2 (en) | 2001-08-15 | 2004-01-06 | Motorola, Inc. | Method for manufacturing a substantially integral monolithic apparatus including a plurality of semiconductor materials |
| KR100419425B1 (en) * | 2002-02-01 | 2004-02-21 | 삼성전자주식회사 | Circuit for controlling output of idle pattern in gigabit ethernet - passive optical network |
| US7630639B2 (en) | 2003-09-15 | 2009-12-08 | Teknovus, Inc. | Method and apparatus for transmission control in an ethernet passive optical network |
| JP4860137B2 (en) * | 2004-11-12 | 2012-01-25 | 日本電気通信システム株式会社 | Optical access network method, optical access network, and optical switch for optical access network |
| CN101459473B (en) * | 2007-12-14 | 2012-01-25 | 华为技术有限公司 | Optical beam splitter, optical beam combiner and point-to-multipoint network system |
| JP5301364B2 (en) * | 2009-06-17 | 2013-09-25 | 日本電信電話株式会社 | Optical access system and optical repeater |
| CN102577182B (en) * | 2011-12-28 | 2014-11-05 | 华为技术有限公司 | Optical line terminal and method for processing amplified spontaneous emission by same |
| JP2014096649A (en) * | 2012-11-08 | 2014-05-22 | Toshiba Corp | Virus interruption system |
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| DE3507064A1 (en) * | 1985-02-28 | 1986-08-28 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | OPTICAL NEWS TRANSMISSION SYSTEM IN THE SUBSCRIBER AREA |
| US5150247A (en) * | 1989-10-30 | 1992-09-22 | Broadband Technologies, Inc. | Fiber optic telecommunication system employing continuous downlink, burst uplink transmission format with preset uplink guard band |
| US5153762A (en) * | 1990-03-19 | 1992-10-06 | General Instrument Corporation | Method and apparatus for recovering AM channell signals distributed on an optical fiber |
| ES2104740T3 (en) * | 1991-02-11 | 1997-10-16 | Alsthom Cge Alcatel | OPTICAL COMMUNICATION SYSTEM FOR THE SUBSCRIBER CONNECTION AREA WITH OPTICAL AMPLIFIERS. |
| IT1247845B (en) * | 1991-03-29 | 1995-01-02 | Pirelli Cavi Spa | OPTICAL FIBER TELECOMMUNICATION LINE WITH PROTECTION DEVICE FOR OPTICAL AMPLIFIERS |
| JP2661438B2 (en) * | 1991-09-24 | 1997-10-08 | 日本電気株式会社 | Optical regeneration repeater |
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| JP3320452B2 (en) * | 1992-07-15 | 2002-09-03 | 沖電気工業株式会社 | Monitoring and control method for optical repeaters |
| US5241414A (en) * | 1992-08-21 | 1993-08-31 | At&T Bell Laboratories | Fault tolerant optical amplifier arrangement |
| US5392154A (en) * | 1994-03-30 | 1995-02-21 | Bell Communications Research, Inc. | Self-regulating multiwavelength optical amplifier module for scalable lightwave communications systems |
| US5610744A (en) * | 1995-02-16 | 1997-03-11 | Board Of Trustees Of The University Of Illinois | Optical communications and interconnection networks having opto-electronic switches and direct optical routers |
-
1995
- 1995-09-21 ES ES95202553T patent/ES2167399T3/en not_active Expired - Lifetime
- 1995-09-21 DE DE69524751T patent/DE69524751T2/en not_active Expired - Lifetime
- 1995-09-21 EP EP95202553A patent/EP0765045B1/en not_active Expired - Lifetime
-
1996
- 1996-09-11 AU AU65543/96A patent/AU714781B2/en not_active Ceased
- 1996-09-16 US US08/714,342 patent/US5754319A/en not_active Expired - Lifetime
- 1996-09-20 CA CA002186149A patent/CA2186149A1/en not_active Abandoned
- 1996-09-24 JP JP25167296A patent/JP3842349B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| AU6554396A (en) | 1997-03-27 |
| JPH09181686A (en) | 1997-07-11 |
| ES2167399T3 (en) | 2002-05-16 |
| DE69524751T2 (en) | 2002-08-22 |
| EP0765045A1 (en) | 1997-03-26 |
| DE69524751D1 (en) | 2002-01-31 |
| EP0765045B1 (en) | 2001-12-19 |
| AU714781B2 (en) | 2000-01-13 |
| US5754319A (en) | 1998-05-19 |
| JP3842349B2 (en) | 2006-11-08 |
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