CN101341635B - Multistage fibre amplifier and method for adapting a pump power of a multistage fibre amplifier - Google Patents
Multistage fibre amplifier and method for adapting a pump power of a multistage fibre amplifier Download PDFInfo
- Publication number
- CN101341635B CN101341635B CN2006800246541A CN200680024654A CN101341635B CN 101341635 B CN101341635 B CN 101341635B CN 2006800246541 A CN2006800246541 A CN 2006800246541A CN 200680024654 A CN200680024654 A CN 200680024654A CN 101341635 B CN101341635 B CN 101341635B
- Authority
- CN
- China
- Prior art keywords
- power
- fiber
- signal
- pump signal
- pump
- 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.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
- H01S3/06758—Tandem amplifiers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094003—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre
-
- 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
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094061—Shared pump, i.e. pump light of a single pump source is used to pump plural gain media in parallel
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2210/00—Indexing scheme relating to optical transmission systems
- H04B2210/003—Devices including multiple stages, e.g., multi-stage optical amplifiers or dispersion compensators
Abstract
The invention relates to a multistage fibre amplifier having a first amplifying fibre (EDFI) and at least one further amplifying fibre (EDF2) connected in series, and also a pump source (2D), a first pump signal (AI) being fed to the first amplifying fibre (EDFI) and a further pump signal (A2) being fed to the further amplifying fibre (EDF2). The multistage fibre amplifier is distinguished by the fact that the further pump signal (A2) is fed to the further amplifying fibre (EDF2) via a power-dependent attenuation element (ZFED). The attenuation element (ZFED) is formed in such a way that, as the pump power increases, small further pump signals are attenuated to a greater extent than large further pump signals. The power-dependent attenuation of the pump signal (A2) fed to the further amplifying fibre primarily results in improvements in the noise figure of the multistage amplifier.; A method for adapting the pump power of the multistage fibre amplifier according to the invention is furthermore specified. This involves a modified feedforward control which advantageously compensates for the delays brought about by the additional fibre on changes in the input signal power. An improved dynamic behaviour of the multistage fibre amplifier is achieved by means of the method according to the invention.
Description
Technical field
The present invention relates to a kind of multi-stage fiber amplifier and a kind of method that is used to mate the pump power of multi-stage fiber amplifier.
Background technology
In optics long distance communication network, for signal amplifies, use fiber amplifier usually, its amplifying fiber is doped with the element from rare earths mostly.Commercial, mainly adopt erbium-doped fiber amplifier (EDFAs be abbreviated as in English " Erbium doped fiber amplifiers "), these fiber amplifiers are made of a plurality of amplifying stages usually.Below, the part with EDFA is called amplifying stage respectively, and wherein this part comprises the Er-doped fiber that is connected just, and this optical fiber is disposed in passive component, for example between the optical fiber or isolator (Isolatoren) of variable attenuating elements, compensation of dispersion.
There is multiple device in the literature, is used for multistage erbium-doped fiber amplifier is carried out pumping (pumpen).The pump signal is propagated in the same way or oppositely with optical transmission signal in the case.For conveying capacity, adopt one or more pump laser diode at each amplifying stage usually so far.In the two-stage fiber amplifier, the pump laser diode that also uses different wave length is as pumping source.Pump laser with emission wavelength of 980nm for example is responsible for the height counter-rotating that the optical fiber in the first order begins to locate, and the laser with emission wavelength of 1480nm is the second amplifying stage supplying energy after the isolator.Thus, can in very large input power range, under the situation of enough power outputs, realize good noise factor.
In order to save cost, what be worth expectation is only also to use a pump laser diode as pumping source, so that multi-stage fiber amplifier is carried out pumping.This especially the huge advance made of the attainable power output by laser diode become possibility.Having can be in commercial acquisition up to the pump laser diode of 500mW.Distinguish two kinds of pump arrangements in principle, utilize these two kinds of pump arrangements that the pump power of laser diode is distributed to for example two amplifying stages.Fig. 1 a) and 1b) in the embodiment of this pump arrangement has been shown.In this respect, see also United States Patent (USP) 5430572.
Fig. 1 a illustrates the known pump arrangement of the two-stage fiber amplifier with pumping bypass, and this pump arrangement is illustrated as block diagram.The light data-signal of the wavelength about 1550nm is fed to the first input end of wavelength selective coupler WDM1 by isolator I at input side.Second input of coupler WDM1 is corresponding to the pumping input, and the output of the laser diode LD of the emission wavelength of 980nm is connected with for example having.Pump signal A1 that is launched and optical transmission signal are fed to the first er-doped amplifying fiber EDF1 subsequently, and transmission signals is exaggerated there and the part of pump signal is absorbed.The transmission signals that is exaggerated is by coupler WDM, be fed to the second er-doped amplifying fiber EDF2 by other isolator IB and by coupler WDM2, and wherein said other isolator IB is disposed between the first amplifying stage S1 and the second amplifying stage S2.Second output of wavelength selective coupler WDM is connected with second input of coupler WDM2.By pumping bypass PB, unabsorbed pump signal A2 is coupled output in the first amplifying stage S1, and is coupled again after isolator IB and is input among the second amplifying stage S2.The pumping bypass is owing to absorb the height of pump signal in isolator IB but essential.By US patent 5430572, Fig. 4 discloses device identical on a kind of principle, and wherein pump signal and transmission signals are oppositely propagated.In the case, the pump signal of laser diode is coupled input by wavelength selective coupler, and this wavelength selective coupler is disposed in after second amplifying fiber.
Pump arrangement with pumping optical splitter (Pumpsplitter) has been shown in the block diagram of Fig. 1 b.In the case, the pump signal of laser diode LD is fed to amplifying stage S1 and S2 by pumping optical splitter PS.The pumping optical splitter has usually and is used to carry two inputs of signal E1 and E2 and has two outputs, and on power division to the two amplifying stage S1 and S2 of the pump signal that will launch by laser diode according to the division factor (1-α) that is provided with regularly: α.At european patent application 0650234A1, this device has been described equally among Fig. 3.According to Fig. 1 b of this application, first output of pumping optical splitter PS is connected with the wavelength selective coupler WDM1 of the first amplifying stage S1.Second output of pumping optical splitter PS is connected with other coupler WDM2, and this other coupler WDM2 is disposed in the place that begins of second level S2.By this way, the first pump signal A1 is fed to the first amplifying fiber EDF1, and other pump signal A2 is fed to other amplifying fiber EDF2.Utilize this structure, compare with the structure among Fig. 1 a and can realize higher power output.In the case, the division factor of power coupler is the important degree of freedom, and this degree of freedom allows the pair amplifier function to be optimized.Yet disadvantageously, the division factor of pumping optical splitter PS is determined in the stage in Design of Amplifier usually, and can not be complementary with input power or desirable power output at run duration.
Except the desirable signal that causes owing to stimulated emission amplifies, image intensifer also has the spontaneous emission (English " amplified spontaneous emission " that is exaggerated, abbreviation ASE) broadband noise of form, this broadband noise causes the reduction of signal to noise ratio.In order to realize as far as possible little noise factor (English " noise figure ", abbreviation NF) at the output of multistage EDFA, should be big as far as possible in the total signal power (hereinafter referred to as power output) of the output of each amplifying stage.But simultaneously, particularly under the situation of the amplifier that is used for very long transmission line, the noise factor of the first order should be as far as possible little, because the noise factor of the first order at first determines the noise characteristic of whole device in multi-stage fiber amplifier.The noise characteristic of multi-stage fiber amplifier and peak power output generally depend at total signal power at amplifier input terminal place (hereinafter referred to as input power) and pump power at different levels.
Different division factor at the pumping optical splitter PS in the two-stage amplifying device of Fig. 1 b in Fig. 2 show as power output P
OutThe distribution of the noise factor NF (providing) of the function of (providing) with dBm with dB.Also the pump arrangement at Fig. 1 a illustrates noise factor NF to power output P
OutDependence.Starting point is: the pump power by the laser diode LD emission is limited in about 250mW.In addition, the gain of the amplifying stage of being considered is regulated by suitable pump power and is held constant and is approximately 20dB.Because there is linear relationship in constant gain between input and output power.Input power is calculated, and makes on the spectrum width of 40 channels total power input to be set, and this total power input is usually corresponding to the power of independent channel.The total power input of Xuan Zeing is changed in emulation like this.In practice, the change of input power realizes by the variable power of different channel occupancies or the signal by one or more channels.Curve A illustrates the noise characteristic of the pump arrangement with pumping bypass among Fig. 1 a, and by curve B _ 0.2 to B_0.8, the strong influence of first and second amplifying stages of the pump arrangement with pumping optical splitter among the branch of pump power pairing Fig. 1 b becomes obvious.To B_0.8, division factor increases to 0.8 from the 0.2 for curve B _ 0.2, i.e. the pump signal A1 that coupling is input in the first erbium optical fiber increases.Can see significantly, even noise factor is for little power output and because constant gain is also very big for little input power, and, constantly reduce along with the power output that increases when coupling is input to pump signal A1 in first amplifying stage when being enhanced.Yet also becoming is apparent that, maximum thus attainable power output P
Out, maxReduce a plurality of dBm.Maximum attainable power output P at desired yield value
Out, maxBe characterised in that amplifier gain also is not in the zone of saturation.Consider transmission system, when definite input signal power given in advance and the pump power determined, maximum attainable power output P
Out, maxNoise factor NF with the maximum appearance
MaxCharacteristic quantity as fiber amplifier is important.
Being used for the commercial modern wdm system of using can move with nearly 160 channels on the corresponding wavelength, but it can only bring into operation with a few channel usually.Therefore, quite little in the moment that brings into operation in the input power (also having power output under the situation in constant gain) of the input end of fiber amplifier, and obviously bigger input power may appear later on.But transmission line must be designed, feasible particularly being satisfied in big power bracket in the essential requirement aspect the signal to noise ratio signal quality.
If the input power at the input end of fiber amplifier when connecting or disconnecting channel changes, then need to make the dynamic characteristic of input power and fiber amplifier to mate.Therefore, the obvious gain fluctuation of amplifying signal for example appears wanting at the input end of casacade multi-amplifier under the situation of signal input power decline 16dB.Yet, in order to prevent that signal gain should not change when connecting or disconnecting channel in the bit mistake of the end of transmission line.
Summary of the invention
Task of the present invention is, provides a kind of multi-stage fiber amplifier, utilizes this multi-stage fiber amplifier to realize the noise factor that improves on the input power range that changes.
Another task of the present invention is to improve the dynamic characteristic of this multi-stage fiber amplifier.
These tasks are by multi-stage fiber amplifier according to the present invention, by being used to mate the method for pump power and solving by multi-stage fiber amplifier according to the present invention according to of the present invention.
According to the present invention, a kind of multi-stage fiber amplifier is provided, this multi-stage fiber amplifier has other amplifying fiber and at least one pumping source of first amplifying fiber and at least one series connection, wherein first pump signal is fed to described first amplifying fiber, and other pump signal is fed to described other amplifying fiber, it is characterized in that, be provided with the attenuating elements relevant with power, described other pump signal is fed to described other amplifying fiber by this attenuating elements, wherein said attenuating elements is configured, make that along with the pump power that increases the decay of described other pump signal reduces.
According to the present invention, a kind of method that is used to mate the pump power of multi-stage fiber amplifier is provided, in this multi-stage fiber amplifier, light signal is amplified, and this multi-stage fiber amplifier comprises the other amplifying fiber of first amplifying fiber and at least one series connection, and wherein first pump signal is fed to described first amplifying fiber, and other pump signal is fed to described other amplifying fiber, and use a kind of adjusting, this adjusting according to the input power of described signal in the detected change calculations in amplifier in place and the new rated value of total pump signal is set, make the gain of described signal keep constant as far as possible, it is characterized in that, the part of total pump signal is transferred described other amplifying fiber by the additional optical fiber with decay relevant with power, this additional optical fiber is along with the pump power of the increase of the total pump signal described other pump signal that decays more weakly, and after the power of described signal changes, the current power value of total pump signal is changed suddenly, up to surpassing or less than its new rated value, and subsequently progressively near the new rated value of total pump signal.
According to the present invention, a kind of multi-stage fiber amplifier is provided, has pumping source, the total pump signal of this pumping source is assigned on the other amplifying fiber of first amplifying fiber and at least one series connection, has regulon, calculate and be provided with the new rated value of total pump power according to the power of signal in this regulon in the detected variation in amplifier in place, it is characterized in that, be provided with additional optical fiber with decay relevant with power, the part of total pump signal is fed to described other amplifying fiber by this additional optical fiber, and described regulon makes up according to the enforcement flexible program of said method.
Provide a kind of multi-stage fiber amplifier, it has other amplifying fiber and at least one pumping source of first amplifying fiber and at least one series connection, wherein first pump signal is fed to first amplifying fiber, and other pump signal is fed to other amplifying fiber.According to the present invention, be provided with the attenuating elements relevant with power, described other pump signal is fed to described other amplifying fiber by this attenuating elements.This attenuating elements is configured, and makes little other pump signal compare more consumingly with big other pump signal and be attenuated along with the pump power that increases.By inserting the attenuating elements relevant in the pump path between the amplifying fiber after pumping source and one or more first amplifying fiber that is connected casacade multi-amplifier with power, the division ratio of change pump power to each amplifying stage.Be implemented in the obvious improvement of the noise characteristic aspect of whole device thus.This is specially adapted to have the input signal of little total power input, and when only having a few channels occupied, this always exists.
In a kind of favourable enforcement flexible program, designed a kind of casacade multi-amplifier with pump arrangement of band pumping bypass.The residue pump signal flows to described other amplifying fiber as other pump signal by the attenuating elements relevant with power, and this causes the obvious improvement of the amplifier function aspect noise factor.
In the favourable enforcement flexible program of another kind, casacade multi-amplifier is equipped with the pump arrangement of band pumping optical splitter.At this, other pump signal is fed to other amplifying fiber by the attenuating elements relevant with power.Particularly, obtain the obvious improvement aspect noise factor for this device.
By using Er-doped fiber as the attenuating elements relevant the additional optical fiber of er-doped (below be also referred to as) with power, particularly when mating, advantageously realize little insertion decay by the standard fiber of selecting core diameter to make the mode field diameter of additional optical fiber and to use in addition.In addition, can advantageously be arranged on the noise characteristic and the power output of the output of multi-stage fiber amplifier by the length of additional optical fiber.In addition, the use of additional optical fiber according to the present invention in pump path is to have the extremely low realization of the cost of the attenuating elements of the decay relevant with power.
In addition, provide a kind of method that is used to mate according to the pump power of multi-stage fiber amplifier of the present invention, this multi-stage fiber amplifier is included in the additional optical fiber with decay relevant with power in the other pump path, wherein use a kind of adjusting, the new rated value of pump signal is calculated and be provided with to this adjusting according to the input power of signal in the detected variation in amplifier in place, makes the gain of signal keep constant as far as possible.According to the present invention, in the method, after the power of signal changed, the current power value of pump signal was changed suddenly, up to surpassing or less than its new rated value, and subsequently progressively near the new rated value of pump signal.This means that improved feed-forward regulation according to the present invention at first is set to pump power than for the lower value of the required value of the stable state after keeping starting of oscillation when input signal power reduces.By this early stage overcompensation to pump power, the advantageously delay that causes by additional optical fiber according to the change of input signal power compensation and tiding over up to the time that reaches the starting of oscillation state.The gain fluctuation of signal advantageously is reduced thus.
Description of drawings
Further describe the present invention by embodiment now.Wherein:
Fig. 3 illustrate according to Fig. 1 b, have a block diagram that in pump path, is used for other pump signal A2 according to additional optical fiber of the present invention;
Fig. 4 a)-4c) at have or not according to the situation of additional optical fiber of the present invention under the division factor given in advance of pumping optical splitter the noise factor of whole device of the device that is used for showing Fig. 3 is shown to the dependent figure of gross output;
Fig. 5 illustrates the noise factor of whole device of the device that is used for showing Fig. 3 to the dependent figure of gross output at the different length of the division factor given in advance of pumping optical splitter and additional optical fiber;
Fig. 6 illustrates the block diagram of the enforcement flexible program of pump in accordance with the present invention pump apparatus;
Fig. 7 illustrates the block diagram of another enforcement flexible program of pump in accordance with the present invention pump apparatus;
Fig. 8 illustrates the signal gain G of the whole device that is used to show amplifier at the different length of additional optical fiber
SIGDependent figure;
Fig. 9 illustrates the flow chart that is used to show according to feed-forward regulation of the present invention;
Figure 10 a illustrates the figure of the total pump power of the time of depending at feed-forward regulation according to the present invention;
Figure 10 b illustrates the figure of the signal gain of the time that depends at the different length of additional optical fiber.
Embodiment
Corresponding to the block diagram of the two-stage fiber amplifier with pumping optical splitter shown in Fig. 1 b, in this two-stage fiber amplifier, the light signal SIG that is carried is exaggerated block diagram shown in Figure 3 in principle.The emission wavelength of laser diode LD for example is fed to pumping optical splitter PS for the output signal of 980nm, and the total pump signal is divided according to division factor given in advance there.The A1 of first of total pump signal or first pump signal are fed to the first amplifying fiber EDF1 by the pumping input of the first wavelength selective coupler WDM1.Other pump power part A 2 is by additionally inserting in the pump path and the optical fiber ZFED of er-doped is fed to the pumping input of the second coupler WDM2 of the second amplifying fiber EDF2.Shown two-stage fiber amplifier is connected on the regulon R.At this, can relate to gain or power output and regulate.In order to regulate purpose, be furnished with the photodiode PD that is connected with regulon R at the input side and the outlet side of two-stage fiber amplifier
EAnd PD
ARegulon R determines the pump power by the laser diode LD emission.
Utilize the additional optical fiber ZFED of er-doped, the pump signal A2 and the power that are fed to the second amplifying stage S2 are attenuated relatively.Little pump signal is absorbed more strongly, and is additionally decayed thus.Big pump signal is absorbed in optical fiber owing to absorb saturation effect more weakly, and less is attenuated thus.Be coupled the pump power that is input among the second amplifying stage S2 by decay, reduce equally in the power output of partial output.Yet when moving with constant gain, regulon compensates supplementary load loss by correspondingly improving the pump power that is sent by laser diode LD, makes gain remain unchanged.By improving this pump power, the also pumping first amplifying stage S1 more strongly, this produces active influence to noise factor.The decay of pump power in additional optical fiber reduces thus equally, but the desired value of the power output of fiber amplifier is held and stable status occurs thus.
The variation of the decay of pump power in additional optical fiber and the corresponding adjusting of pump power cause the variation of the distribution of pump power to each amplifying stage effectively.Especially under the situation of little pumping and signal input power, pump power helps the first order and is enhanced, and this noise factor to the output of dual-stage amplifier produces remarkable influence, as shown in FIG. 4.Replace the additional optical fiber of er-doped, also can use, as long as this optical fiber has comparable absorption characteristic in desirable wave-length coverage with the optical fiber of another kind from the element doping of rare earths.Also can imagine the hardware component or the correspondingly in check attenuating elements of the realization of using other decay relevant with power.
In Fig. 4 a to 4c respectively at the division factor of the pumping optical splitter PS among Fig. 3 0.4: 0.6; 0.5: 0.5 and provide the noise factor as the function of power output of the output of dual-stage amplifier at 0.6: 0.4.Gain is constant in all cases.The curvilinear motion that is shown in dotted line is respectively to use according to the noise factor under the additional optical fiber situation of the present invention.Solid-line curve is the noise factor that does not use additional optical fiber, and consistent with curvilinear motion B_0.4, B_0.5 and B_0.6 among Fig. 2.In Fig. 4 a, the pump power that is fed to first amplifying fiber partly is 40%.Because noise factor is compared with the second level at this more weakly by pumping, so the noise factor of curve B _ 0.4 (not using additional optical fiber under the situation of this curve in second pump path) is compared bigger with Fig. 4 b with curve B _ 0.5 among the 4c with B_0.6 by the decision of first amplifying stage and this first amplifying stage.And in second pump path, for all division factor, demonstrate the obvious improvement of noise characteristic according to the use of additional optical fiber of the present invention.The noise factor of curve B _ 0.4Z, B_0.5Z and B_0.6Z all is positioned under curve B _ 0.4, B_0.5 and the B_0.6 for all division factor.For the desired value of power output, under any circumstance all guarantee less noise factor by additional optical fiber according to the present invention.Additionally, peak power output P
Out, maxKeep identical approx.
A plurality of division factor at the pumping optical splitter PS in Fig. 1 b or Fig. 3 and 4 in Fig. 5 show by mentioned characteristic quantity (P
Out, max, NF
Max) numerical value that constitutes is to (illustrating with star).The pump power part A 1 that is fed to first amplifying fiber reduces from left to right at this.At first in pump arrangement, do not use according to determining under the situation of additional optical fiber of the present invention that numerical value is right.The right connection of each numerical value obtains with the curve B _ MAX shown in the black, and this curve is dull to rise, because along with pump power part A 1 becomes more and more littler in the first order, in the dull rising of the noise factor of partial output.Under situation, respectively the fixing division factor of pumping optical splitter PS is brought up to 10m from 0m with the step-length of 0.5m as the length of basis and additional optical fiber with the curve shown in the grey.By this way, obtain curve K_0.4 to K_0.7.With curve K_0.5 is the influence of the length of the example additional optical fiber of describing er-doped.Do not having under the situation of additional optical fiber, the maximum noise factor that occurs is 6.1dB, and can realize the peak power output of about 16.8dB.By inserting additional optical fiber, noise factor reduces at first significantly, and peak power output is almost constant.In contrast, under the situation of length greater than 5.0m of additional optical fiber, the raising of fiber lengths causes worth mentioning improvement of noise factor, and peak power output reduces now greatly.Under the situation of the length of suitably selecting additional optical fiber, therefore can realize the noise factor that maximum occurs is reduced about 0.4dB, and peak power output only reduces about 0.1dB.Therefore except the division factor of pumping optical splitter, the length of the additional optical fiber of er-doped also is to be used to optimize two characteristic quantity (P
Out, max, NF
Max) important way.
Two embodiment of the pump arrangement of two-stage fiber amplifier have been shown in Fig. 6 and 7, and they are respectively at the attenuating elements relevant with power that has the additional optical fiber ZFED form of er-doped to the pump path of second amplifying stage.
Figure 6 illustrates the block diagram of pump arrangement with pumping optical splitter.Different with the enforcement flexible program among Fig. 3, at this, two inputs of pumping optical splitter E2 are used to insert unabsorbed pump power (English " residual pump power (residue pump power) "), and this pump power is also referred to as the residue pump signal.The first pump signal A1 is fed to the first Er-doped fiber EDF1 by the first wavelength selective coupler WDM1.Unabsorbed pump power is fed to pumping optical splitter PS by other wavelength selective coupler WDM as residue pumping power level from the output of amplifying fiber EDF1 in amplifying fiber.Thus, more pump power can use for whole amplifying device.Additionally, compare with the structure of not utilizing the residue pump power, the division factor that is provided with regularly of optical splitter can be changed a little.Particularly under the situation of the division factor (pump power of first order part is greater than partial pump power part under the situation in these division factor) of the regulation of pumping optical splitter, be coupled be input to the power in the amplifying fiber relation only by using the residue pump power to change.Can select the division factor stipulated thus, make the pump power part A 1 be fed to the first order be enhanced, even because second optical fiber in order to realize that the required pump power level of peak power output also still can be provided under the situation of this reformed division factor.For example, under the situation of the division factor of about (1-α): the α that is provided with regularly of optical splitter PS=60: 40, division factor can remain pump power and be changed about 65: 35 value that several percentages change to the first order that helps in the design phase by using.This means, shown in situation in, also can realize the improvement slightly of noise factor even without ZFED.And by using ZFED, be implemented in the variation that all helps the division factor of the first order in any case, because in case the output power output of amplifier installation owing to the pump power level that is fed to second amplifying stage reduce descend, regulon will always improve the power output of pumping source LD.The additional advantage of the device among Fig. 6 is that by using the residue pump power, the maximum noise factor that occurs can be further reduced.
In Fig. 7, be inserted in the pump path of the pump arrangement among Fig. 1 b with pumping bypass according to the additional optical fiber ZFED of er-doped of the present invention.The first pump signal A1 is fed to the first amplifying fiber EDF1 by the pumping input of the first coupler WDM1.After this first amplifying fiber, be connected with coupling element WDM, the mode that the signal that this coupling element will exist in the end of amplifying fiber is selected with wavelength is divided into data-signal and residue pump signal, wherein this data-signal is fed to other amplifying fiber EDF2, and this residue pump signal is fed to other amplifying fiber EDF2 as other pump signal A2 by the attenuating elements ZFED relevant with power.In this case, also the variation relevant with power by pump power is implemented in the reducing of power output of the output of second amplifying stage, and regulon improves the power output of pumping source LD and more pump power and is coupled and is input in first amplifying stage thus.As a result of, determine to compare the improvement slightly of noise factor with the curvilinear motion A shown in Fig. 2.
Can imagine in the amplifying device that has more than two amplifying fiber, the power output of high-power laser diode for example is assigned on three amplifying fibers.If select to have the pump arrangement (2 two-way optical splitters (2 auf 2-Splitter) or multichannel optical splitter) of pumping optical splitter for this reason, then preferably in the pump path of leading to one of last amplifying fiber, insert the additional optical fiber ZFED of er-doped in order to realize optimum noise characteristic.So the amplifier function depends on the length of the additional optical fiber of the division factor of different pumping optical splitters and er-doped again.
For what all mentioned amplifying devices were suitable for be, when the design amplifier, must manage to accomplish, not interference laser operation of the ASE that in additional optical fiber, is produced.Under the situation of Fabry-Bai Luo (FP) laser diode, do not produce any problem, because these laser diodes have integrated isolator.Yet under the situation of the laser diode with Fiber Bragg Grating FBG (FBG), possibility must connect isolator or have the parts of the decay relevant with wavelength after laser diode.
Yet when using traditional feed-forward regulation that pump power is set, the dynamic characteristic of fiber amplifier worsens when connecting or disconnecting channel under the situation of using additional optical fiber to partial pump path.In this case, when the input end signal input power of casacade multi-amplifier for example descends 16dB, the obvious gain fluctuation of amplifying signal SIG occurs treating, this can be as seen from Figure 8.In Fig. 8, show the signal gain G of the whole device of amplifier at the different length of the additional optical fiber between 0 to 6m according to time t
SIGAdditional optical fiber ZFED is long more, the overshoot of signal gain
Just high more.Under the situation of the big power saltus step of input signal, the duration of overshoot is also along with the length of the increase of additional optical fiber and increase.Yet in order to prevent the bit mistake in the end of transmission line, for disposing at the amplifier shown in Fig. 3 according to of the present invention, signal gain should not change when connecting or disconnecting channel yet.
In Fig. 9, show the processing mode that is modified according to each job step of feed-forward regulation of the present invention with flow chart.Suppose in this embodiment: this adjusting is born by digital signal processor, and this digital signal processor is provided with pump power in the discrete moment.But this method also goes for simulation or mixes and regulate.
At first, carry out initial phase 1.This for example can realize during adjusting brings into operation or during the manufacturing of amplifier card.For this reason, receive whole measuredly, and for example the memory location of digital signal processor is occupied by reference value.Like this, especially, the understanding of gain that in the stable state after the starting of oscillation of fiber amplifier depending on of additional optical fiber is fed to the pump power of this additional optical fiber is indispensable for adjustment process.This pumping characteristic curve of additional optical fiber has been shown in the illustration 1a of Fig. 9, this pumping characteristic curve sign corresponding to the pump signal of the output of additional optical fiber and depend on the pump signal at beginning of additional optical fiber, in the gain G of the relation of the pump signal of the input end of additional optical fiber
pThis measurement should preferably just be carried out when making amplifier.Usually, measure the characteristic curve of sample and then that it is also enough as EDFA that typical curve is used for all productions later on.In measurement, the P of pump power arbitrarily of the output signal of laser diode
TotBe set up, and in the long time, be held constant.Stable state appears.For this stable state, at pump power P
TotWith additional optical fiber G
pCorresponding yield value write in the memory location.Be noted that during measuring do not have signal to be backscattered to the additional optical fiber, and have only when the stable state after the starting of oscillation that has reached casacade multi-amplifier, just measure from amplifying stage.
At the run duration (this represents by frame 2) of amplifier, under the situation of hypothesis stable state, total pump signal P is set by the standard feed-forward technique in Fig. 9
TotFirst the value.The gain of additional optical fiber is set to stable state according to the characteristic curve of mentioning in 1.Belong to P
TotYield value G
pBe stored in the memory location.In addition, this value is assigned to the current gain value that is used for additional optical fiber
Other memory location, to determine the initial conditions of control method.Be suitable for:
As an example, at this, starting point is total pump power P
Tot=200mW.At G
p, obtain about 0.95 value by the illustration 1a of Fig. 9.
If owing to disconnecting the power saltus step 3 that the signal power of fiber amplifier appears in channel, then the pump power of pump laser diode LD is mated by adjusting and is reduced now.At this situation, in job step 4, calculate the current power value of pump signal according to following rule
In this formula:
α generally represent total pump power the part that is fed to additional optical fiber (for example, 0.2 ..., 0.9),
P
TotGenerally be illustrated in during the stable state by total pump power or total pump signal that pump laser diode sent,
G
pThe yield value of general expression additional optical fiber, the pump power P in this yield value and the stable state
TotBe associated, and
The current gain value of general expression additional optical fiber, this current yield value and the current total pump power after the power of input signal changes approx
Be associated.
Directly after the power of input signal changes, measure P
TotAnd G
pBe made as the value of wanting newly-installed stable state immediately, P
TotFor example be set as 20mW from 200mW, and G
pBe set as 0.7 (referring to the characteristic curve among the illustration 1a of Fig. 9) from 0.95.Yet, when adjustment process begins, at first calculate the median of current pump signal, because current gain value by above-mentioned formula
Memory also by the yield value G of " old " stable state
pOccupy.The current power value of such acquisition of pump signal
So, but directly be under the rated value of expectation in the transition stage after the power saltus step also not corresponding to the newly-installed rated value of wanting of the total pump power of stable state.In given example, at
Approximately be provided with the value of 15.4mW.(referring to Figure 10 a) if not the reduction that relates in the input power of the input end of fiber amplifier, and relate to the increase of input power, then the current power value of total pump signal
Directly after the signal power saltus step, be on the rated value of wanting newly-installed stable state.
Yet the total pump power that will be provided with must be calculated under the situation of the current gain of considering additional optical fiber.Therefore, in job step 5, calculate the in esse gain of additional optical fiber
Modeling about gain, for example can seek help from publication " Gain dynamics of doped-fiber amplifiers fuer addedand dropped signals " (the 1998 IEEE Int.Conference onCommunications that A.Bononi and L.A.Rusch show, Atlanta, Con.Record., Cat.No.98CH36220).This publication comprises a plurality of equations, be used to calculate sometime at interval in the change in gain of appearance.Utilize this result calculated, before also by G
pThe memory location that occupies is occupied again.(job step 6)
Subsequently, according to job step 4, in the current gain value of the additional optical fiber of considering previous calculations
Situation under calculate and be provided with the new current power value of pump signal
For this reason, the formula that use provides above, wherein P
TotThe performance number of the pump signal of the newly-installed stable state of indicating, and G
pThe yield value of the additional optical fiber of the newly-installed stable state of indicating.Current gain value
Calculating and the current power value of setting and pump signal
Calculating and be provided with continued always, up to the current power value of total pump signal
New rated value P with the total pump signal of wanting newly-installed stable state
TotConsistent.
Advantage according to feed-forward regulation of the present invention can be found out by Figure 10 a and 10b.In Figure 10 a, total pump power has been shown
Time dependence.The distribution of total pump power when imaginary curve 1 is illustrated in use standard feed forward method.The distribution of total pump power when solid-line curve 2 is illustrated in use according to the feed forward method with above-described correction calculation of the present invention.When coupling is input to power in the additional optical fiber in 0 great-jump-forward ground variation constantly, utilize the method according to this invention to provide approximate solution, according to this approximate solution, the storage of the erbium atom in the additional optical fiber and the average occupation probability that also has metastable level thus according to exponential law progressively near final value.Under the situation that 0 signal input power great-jump-forward ground reduces constantly, obtain the curve 2 shown in Figure 10 a.
In Figure 10 b, drawn signal gain G as the whole device of the function of time at the different length of the additional optical fiber between 0 to 6m
SIGDistribution.Different with Fig. 8, used here according to feed forward method of the present invention.Demonstrate, the height of overshoot obviously reduces.Also no longer can determine the length dependent of gain profiles up to the length of the additional optical fiber of 6m.The result shows that the insertion of additional optical fiber causes worth mentioning variation of dynamic characteristic in the pump path in conjunction with improved feed-forward regulation.This means that by feed-forward regulation according to the present invention, the effect of additional optical fiber is almost completely compensated.Thus, when little signal input power, can under situation about dynamic characteristic not being had a negative impact, improve noise factor.
Claims (13)
1. multi-stage fiber amplifier, this multi-stage fiber amplifier has other amplifying fiber (EDF2) and at least one pumping source (LD) of first amplifying fiber (EDF1) and at least one series connection, wherein first pump signal (A1) is fed to described first amplifying fiber (EDF1), and other pump signal (A2) is fed to described other amplifying fiber (EDF2)
It is characterized in that,
Be provided with the attenuating elements relevant (ZFED) with power, described other pump signal (A2) is fed to described other amplifying fiber (EDF2) by this attenuating elements, wherein said attenuating elements (ZFED) is configured, make that along with the pump power that increases the decay of described other pump signal (A2) reduces.
2. according to the multi-stage fiber amplifier of claim 1, it is characterized in that, be connected with coupling element (WDM) afterwards at described first amplifying fiber (EDF1), the mode that the signal that this coupling element will exist in the end of described amplifying fiber (EDF1) is selected with wavelength is divided into data-signal and residue pump signal, wherein said data-signal is fed to described other amplifying fiber (EDF2), and described residue pump signal is fed to described other amplifying fiber (EDF2) as other pump signal (A2) by the described attenuating elements (ZFED) relevant with power.
3. according to the multi-stage fiber amplifier of claim 1, it is characterized in that, be connected with optical splitter (PS) afterwards at described pumping source (LD), this optical splitter is divided the pump power of described pumping source (LD), and described first pump signal (A1) is fed to described first amplifying fiber (EDF1), and described other pump signal (A2) is fed to described other amplifying fiber (EDF2) by the described attenuating elements (ZFED) relevant with power.
4. according to the multi-stage fiber amplifier of claim 3, it is characterized in that, be connected with coupling element (WDM) afterwards at described first amplifying fiber (EDF1), the mode that the signal that this coupling element will exist in the end of described amplifying fiber (EDF1) is selected with wavelength is divided into data-signal and residue pump signal, wherein said data-signal is fed to described other amplifying fiber (EDF2), and described residue pump signal is fed to the other input (E2) of described optical splitter (PS).
5. according to claim 1,3 and 4 multi-stage fiber amplifier, it is characterized in that, in order to divide pump power, be provided with a plurality of optical splitters (PS) or be provided with the multichannel optical splitter, these optical splitters are divided into a plurality of pump signal (A1, A2 with pump power, ...), described a plurality of pump signal be fed to a plurality of amplifying fibers (EDF1, EDF2 ...).
6. according to the multi-stage fiber amplifier of claim 5, it is characterized in that under the situation more than two amplifying fiber, the described attenuating elements (ZFED) relevant with power is connected before the pumping input of amplifying fiber of last layout.
7. according to the multi-stage fiber amplifier of one of aforesaid right requirement, it is characterized in that the described attenuating elements (ZFED) relevant with power is the optical fiber that is doped with from the element of rare earths.
8. the multi-stage fiber amplifier that one of requires according to aforesaid right is characterized in that, is doped with from the length of the optical fiber of the element of rare earths or mixes optimised according to the noise factor and the power output of described fiber amplifier.
9. method that is used to mate the pump power of multi-stage fiber amplifier,
In this multi-stage fiber amplifier, light signal (SIG) is amplified, and this multi-stage fiber amplifier comprises the other amplifying fiber (EDF2) of first amplifying fiber (EDF1) and at least one series connection, and
Wherein first pump signal (A1) is fed to described first amplifying fiber (EDF1), and other pump signal (A2) is fed to described other amplifying fiber (EDF2), and
Use a kind of adjusting, this adjusting according to the input power (Pin) of described light signal (SIG) in the detected change calculations in amplifier in place and total pump signal (P is set
Tot) new rated value, make the gain of described light signal (SIG) keep constant as far as possible,
It is characterized in that,
Total pump signal (P
Tot) in other pump signal (A2) be transferred described other amplifying fiber (EDF2) by additional optical fiber (ZFED) with decay relevant with power, this additional optical fiber is along with total pump signal (P
Tot) the pump power of the increase described other pump signal (A2) that decays more weakly, and
After the power of described light signal (SIG) changes, the current power value of total pump signal
Be changed, up to surpassing or less than its new rated value (P suddenly
Tot), and subsequently progressively near the new rated value (P of total pump signal
Tot).
10. according to the method for claim 9, it is characterized in that,
-in the stable state of described fiber amplifier, the performance number (P of storage total pump signal
Tot) and the affiliated yield value (G of described additional optical fiber (ZFED)
p),
-make the current gain value (G of described additional optical fiber
p Act) with the yield value (G of stable state
p) equate,
-after the power of described light signal (SIG) changes, at the performance number (P that considers the total pump signal
Tot) and want the yield value (G of newly-installed stable state
p) situation under and considering (G
p Act) situation under, calculate and be provided with the median (PZW) of total pump signal,
-calculate and store the new current gain value (G of described additional optical fiber
p Act),
-at the current gain value (G of the described additional optical fiber of considering previous calculations
p Act) situation under and at the performance number (P that considers the total pump signal
Tot) and the yield value (G that wants newly-installed stable state
p) situation under, calculate and be provided with the new current power value of total pump signal
-current gain value (G
p Act) and the current power value of total pump signal
Calculating and be provided with continued always, up to the current power value of total pump signal
New rated value (P with the total pump signal of wanting newly-installed stable state
Tot) unanimity.
11. the method according to claim 10 is characterized in that, calculates the current power value of total pump signal after power changes approx according to following formula
Wherein:
α represents the part that is fed to described additional optical fiber of total pump signal,
P
TotThe performance number of the total pump signal of the newly-installed stable state of indicating,
G
pThe yield value of the described additional optical fiber of the newly-installed stable state of indicating, and
G
p ActExpression is the current gain value of described additional optical fiber after power changes approx.
12. the method according to claim 10 and 11 is characterized in that, according to the current power value that belongs to the total pump signal of people's such as Bononi the described additional optical fiber of Model Calculation
Current gain value
13. a multi-stage fiber amplifier,
Has pumping source (LD), the total pump signal (P of this pumping source
Tot) be assigned on the other amplifying fiber (EDF2) of first amplifying fiber (EDF1) and at least one series connection,
Have regulon, calculate and be provided with the new rated value (P of total pump power in the detected variation in amplifier in place according to the power (Pin) of signal (SIG) in this regulon
Tot),
It is characterized in that,
Be provided with additional optical fiber (ZFED), total pump signal (P with decay relevant with power
Tot) a part be fed to described other amplifying fiber (EDF2) by this additional optical fiber, and
Described regulon makes up according to claim 10,11 or 12.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102005031897A DE102005031897B4 (en) | 2005-07-07 | 2005-07-07 | Multi-stage fiber amplifier |
| DE102005031897.5 | 2005-07-07 | ||
| DE102005046936.1A DE102005046936B4 (en) | 2005-09-30 | 2005-09-30 | Method for adjusting a pumping power of a multi-stage fiber amplifier and multi-stage fiber amplifier |
| DE102005046936.1 | 2005-09-30 | ||
| PCT/EP2006/063812 WO2007006679A1 (en) | 2005-07-07 | 2006-07-03 | Multistage fibre amplifier and method for adapting a pump power of a multistage fibre amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101341635A CN101341635A (en) | 2009-01-07 |
| CN101341635B true CN101341635B (en) | 2010-12-22 |
Family
ID=37563380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2006800246541A Active CN101341635B (en) | 2005-07-07 | 2006-07-03 | Multistage fibre amplifier and method for adapting a pump power of a multistage fibre amplifier |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN101341635B (en) |
| DE (1) | DE102005031897B4 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005046936B4 (en) * | 2005-09-30 | 2017-10-19 | Xieon Networks S.À.R.L. | Method for adjusting a pumping power of a multi-stage fiber amplifier and multi-stage fiber amplifier |
| EP2101426B1 (en) | 2008-03-13 | 2011-05-11 | Nokia Siemens Networks Oy | Method for controlling an erbium doped fibre amplifier (EDFA) and amplifier arrangement |
| US8817366B2 (en) * | 2009-09-07 | 2014-08-26 | Xieon Networks S.A.R.L. | Optical fiber amplifier with improved transient performance |
| CN106099635A (en) * | 2016-08-31 | 2016-11-09 | 山东海富光子科技股份有限公司 | The 2 mu m waveband linear polarization single frequency optical fiber lasers with power feedback mechanism |
| CN111029892A (en) * | 2019-12-29 | 2020-04-17 | 无锡市德科立光电子技术有限公司 | Pump light loop structure of optical fiber amplifier |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1052234A (en) * | 1989-10-30 | 1991-06-12 | 卡维·皮雷利有限公司 | The low-noise optical amplifier that has the exciting power reflection |
| CN2265548Y (en) * | 1996-02-09 | 1997-10-22 | 清华大学 | Cascade optical fibre amplifier with distribution pumping |
| CN1189724A (en) * | 1996-12-31 | 1998-08-05 | 大宇通信株式会社 | Optical fiber amplifier |
| CN1389758A (en) * | 2001-05-31 | 2003-01-08 | 三星电子株式会社 | Improved wide-band erbium-mixed optical-fiber amplifier |
| EP0932228B1 (en) * | 1998-01-22 | 2004-09-29 | Tyco Telecommunications (US) Inc. | Split-pumped dual stage optical fiber amplifier |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5430572A (en) * | 1993-09-30 | 1995-07-04 | At&T Corp. | High power, high gain, low noise, two-stage optical amplifier |
| US5406411A (en) * | 1993-10-14 | 1995-04-11 | Corning Incorporated | Fiber amplifier having efficient pump power utilization |
| US6366393B1 (en) * | 1999-08-25 | 2002-04-02 | Lucent Technologies Inc. | Fast gain control for optical amplifiers |
-
2005
- 2005-07-07 DE DE102005031897A patent/DE102005031897B4/en not_active Expired - Fee Related
-
2006
- 2006-07-03 CN CN2006800246541A patent/CN101341635B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1052234A (en) * | 1989-10-30 | 1991-06-12 | 卡维·皮雷利有限公司 | The low-noise optical amplifier that has the exciting power reflection |
| CN2265548Y (en) * | 1996-02-09 | 1997-10-22 | 清华大学 | Cascade optical fibre amplifier with distribution pumping |
| CN1189724A (en) * | 1996-12-31 | 1998-08-05 | 大宇通信株式会社 | Optical fiber amplifier |
| EP0932228B1 (en) * | 1998-01-22 | 2004-09-29 | Tyco Telecommunications (US) Inc. | Split-pumped dual stage optical fiber amplifier |
| CN1389758A (en) * | 2001-05-31 | 2003-01-08 | 三星电子株式会社 | Improved wide-band erbium-mixed optical-fiber amplifier |
Non-Patent Citations (1)
| Title |
|---|
| CN 1389758 A,全文. |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101341635A (en) | 2009-01-07 |
| DE102005031897B4 (en) | 2007-10-25 |
| DE102005031897A1 (en) | 2007-01-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8089690B2 (en) | Multistage fiber amplifier and method for adapting a pump power of a multistage fiber amplifier | |
| EP1283566B1 (en) | Optical amplifier for amplifying multi-wavelength light | |
| US7085043B2 (en) | Optical amplifier | |
| US6437907B1 (en) | Wide-band optical fiber amplifier and amplifying method thereof | |
| EP1073166A2 (en) | L-band optical fiber amplifier using feedback loop | |
| US6795236B2 (en) | Cascadable optical amplifier arrangement | |
| CN103580754A (en) | Hybrid optical amplifier with optimized noise figure | |
| CN101341635B (en) | Multistage fibre amplifier and method for adapting a pump power of a multistage fibre amplifier | |
| US6441953B1 (en) | L band multistage amplifier with improved noise figure | |
| US6580552B2 (en) | Shared pump and serial rare earth doped fiber optical amplifiers | |
| CN101908707B (en) | Optical amplifier and a method of light amplification | |
| KR100277360B1 (en) | Erbium-doped fiber amplifiers suitable for long wavelength optical signals | |
| JP5103963B2 (en) | Multistage optical amplifier and control method thereof | |
| US6583922B2 (en) | Optical amplifier site with reduced noise and transmission system utilizing such | |
| EP0954071A1 (en) | Optical fiber amplifier and output power flattening method of optical fiber amplifier | |
| US7061667B2 (en) | Optical amplifiers | |
| EP1128581B1 (en) | Optical amplifier with gain equalizer | |
| US11764536B2 (en) | Optical amplifier for multiple bands | |
| CN117913634A (en) | EDFA with adjustable output power and noise coefficient and corresponding control method and system | |
| KR200222421Y1 (en) | Erbium doped fiber amplifier for long wavelength | |
| JPH11238931A (en) | Optical amplifier | |
| JP2003092449A (en) | Optical fiber amplifier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: XIAOYANG NETWORK CO., LTD. Free format text: FORMER OWNER: NOKIA SIEMENS NETWORKS GMBH Effective date: 20140107 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20140107 Address after: Luxemburg Luxemburg Patentee after: Xiaoyang Network Co., Ltd. Address before: Munich, Germany Patentee before: Nokia Siemens Networks GmbH |