CN1743936A - Light spectrum detecting device and method, and Raman amplifier feedback control device and method - Google Patents

Abstract

A spectrographic detector and method, and Raman amplifier feedback controller and method, said spectrographic detector used for detecting spectrographic with n wave length optical signal in transmission line, n is integer greater than 1, said detector containing at least one first splitter and one second splitter set in transmission line for splitting said optical signal, a filter with inclined insert loss spectrum, first power detector connected with said filter for detecting power of optical signal, second power detector connected with second splitter for detecting power of optical signal. Said invention can realize cooperative control.

Description

Spectrum detection device and method and Raman amplifier feed back control system and method

Technical field

The present invention relates to the light transmission field, be specifically related to the detection of spectrum and the control of Raman amplifier (RAMANamplifier).

Background technology

Fig. 1 has shown the typical structure of an optical transmission system.As shown in Figure 1, signal is sent into optical fiber from transmitting terminal, and by certain Distance Transmission, because of the loss of optical fiber self, transmission signals can be attenuated, and the signal of decay is exaggerated to next stage by first optical relay unit 11 and passes, so circulation.After what transmits, deterioration because of Optical Signal To Noise Ratio, signal can't continue downward biography, recover signal by electric relaying Unit 13 this moment, the light signal of electricity TU Trunk Unit output has a good Optical Signal To Noise Ratio (OSNR), make signal can continue, thereby realize the long-distance transmissions of light signal to the next stage transmission.

The optical relay unit mainly is made up of image intensifer (OA), and effect is that luminous power is amplified.Common image intensifer has Erbium-Doped Fiber Amplifier (EDFA) (EDFA), Raman amplifier and semiconductor optical amplifier (SOA) etc.Various image intensifers all can be introduced noise in amplification process, make the Optical Signal To Noise Ratio deterioration.Wherein the SOA noisiness is the poorest, uses less in optical transmission system.EDFA is because its technology maturation, cost is lower, power consumption is less etc., and characteristics are widely used in optical transmission system.But the noisiness of EDFA is also not fully up to expectations, and traditional optical relay unit is made up of simple EDFA, and the noise that EDFA introduces is excessive, and the deterioration of signal to noise ratio (S/N ratio) has limited the increase of cascade number, thereby limited the distance of without electronic relay than very fast.Raman amplifier has the basis that low-noise characteristic is considered to realize the long Distance Transmission of without electronic relay because of it.Adopt the TU Trunk Unit of Raman amplifier or Raman amplifier+EDFA structure will extend the without electronic relay distance greatly.Fig. 2 is to use the typical structure of the light-repeating ship of Raman amplifier+EDFA, and adjustable optical attenuator wherein (VOA) also can omit.

Along with the application of Raman amplifier in transmission network, the control problem of Raman amplifier is put in face of the equipment supplier day by day.Out-of-control Raman amplifier is very poor to the variation adaptive faculty of circuit situation, can not fine adaptation network requirement.Control to image intensifer at present mainly contains two kinds, and a kind of is automatic gain control (AGC), and promptly no matter how flashlight changes, and can both guarantee that flashlight meets the demands by the gain that this image intensifer obtains.Another kind is automated power control (APC), and promptly no matter how flashlight changes, and the signal light power of exporting from this image intensifer all meets the demands.Adopting AGC still is that APC selects according to the concrete needs of networking.

Control except to gain and power also needs gain spectral or output spectra are controlled in wavelength-division multiplex (WDM) system.Transmit several bundle flashlights in same optical fiber among the WDM, each bundle signal light wavelength difference.Require the gain of each bundle flashlight to meet the requirements in the optical transmission system, thereby gain spectral of pair amplifier (gain is with the curve of wavelength variations) or output spectra (output is with the curve of wavelength variations) claim.Must be consistent such as the gain of each wavelength, or each wavelength power difference slightly according to actual needs.

At present, the control mode of Raman amplifier has following several.

In first kind of prior art scheme, Raman amplifier is not controlled automatically.Just in beginning process, the default power of each wavelength pumping is set.According to the circuit situation, adjust the power of each wavelength pumping again, gain spectral (or output spectra) is met the demands.Lock the value of pump power then, this value that always all keeps in service from now on.The shortcoming of this controlling schemes is: 1, out-of-control Raman amplifier, when the circuit situation changes, can not adjust the adaptation link change automatically, and need human intervention.If 2 unite use with the EDFA of automatic control, the control difficulty of overall optical TU Trunk Unit is very big.

In second kind of prior art scheme, Raman amplifier is carried out power control, and gain spectral is not controlled.The shortcoming of this scheme is: in wdm system, the signal light power difference of each wavelength is big, makes that the power or the OSNR characteristic of each wavelength signals light can not meet the demands after the cascade.

In the third prior art scheme,, the assembly of detecting light spectrum must be arranged in order to realize control to spectrum.Adopt online spectrographic detection module OPM (optical performance monitor) to carry out spectrographic detection in the system that has.Adjust image intensifer according to result of detection, realize feedback procedure.The shortcoming of this scheme is: the spectrographic detection module costs an arm and a leg, and is unsuitable for commercialization at present.

Summary of the invention

The present invention is used to overcome the one or more problems that wherein exist in view of above-mentioned prior art scheme proposes.

An object of the present invention is to provide a kind of spectrum detection device cheaply and method.

Another object of the present invention provides a kind of feed back control system of Raman amplifier cheaply and feedback thereof.

A further object of the present invention provides a kind of optical relay unit that uses above-mentioned Raman amplifier feed back control system.

For achieving the above object, according to an aspect of the present invention, provide a kind of spectral method of detection, may further comprise the steps:

At least one is set first along separate routes and one second shunt in transmission has the transmission line of light signal of n wavelength, wherein n is the integer greater than 1;

Make described at least one first light signal in along separate routes respectively by behind the wave filter with inclined insert loss spectrum, respectively the power of the light signal after the detection filter;

Directly detect the power of the light signal in second shunt;

Determine the spectrum of the described light signal that in described transmission line, transmits according to described at least one first power of the light signal of power and described second in along separate routes of light signal in along separate routes.

According to a further aspect of the present invention, provide a kind of spectrum detection device, be used for detecting the spectrum of the light signal with n wavelength that transmits at transmission line, wherein n is the integer greater than 1, and this device comprises:

At least one first shunt and one second shunt are arranged on the described transmission line, are used for branch and pick out described light signal;

The wave filter with inclined insert loss spectrum that is connected with described at least one first shunt is used for corresponding light signal is carried out filtering respectively;

First power detector that is connected with described wave filter respectively is used for the power of the light signal after the detection filter;

Second power detector directly is connected with second shunt to detect the power of light signal wherein.

Another is invented according to the present invention, and a kind of feedback of Raman amplifier is provided, and may further comprise the steps:

According to the target output spectrum, determine the controlled quentity controlled variable desired value of Raman amplifier;

According to the controlled quentity controlled variable desired value, determine the pump power initial value and the loading of Raman amplifier;

Detect the currency of controlled quentity controlled variable;

Whether the difference of judging currency and desired value is in permissible range;

If not in permissible range, then adjust pump power and loading according to this difference.

According to a further aspect of the present invention, provide a kind of feed back control system of Raman amplifier, comprising:

Spectrum detection device is used to detect the spectrum of the output light signal of Raman amplifier;

Control device, be used for determining the pump power initial value and the loading of Raman amplifier according to the controlled quentity controlled variable desired value, and the spectrum that detects according to spectrum detection device, whether the difference of judging controlled quentity controlled variable desired value and currency is in permissible range, if not in permissible range, then adjust the pump power and the loading of Raman amplifier according to this difference.

According to a further aspect of the present invention, provide a kind of optical relay unit, comprise Raman amplifier and feed back control system thereof, wherein,

Described feed back control system comprises:

Spectrum detection device is used to detect the spectrum of the output light signal of Raman amplifier;

Control device, be used for determining the pump power initial value and the loading of Raman amplifier with the controlled quentity controlled variable desired value, and the spectrum that detects according to spectrum detection device, whether the difference of judging controlled quentity controlled variable desired value and currency is in permissible range, if not in permissible range, then adjust the pump power and the loading of Raman amplifier according to this difference.

This fermentation can be realized cheap spectrum detection device and the controlled Raman amplifier of gain spectral, improves the reliability and the dirigibility of optical transmission system.By sensing point is placed on diverse location, can also realize jointly controlling.

Description of drawings

Fig. 1 has shown the typical structure of optical transmission system;

Fig. 2 has shown the typical structure of the light-repeating ship that comprises Raman amplifier and EDFA;

Fig. 3 is a Raman gain factor distribution plan;

Fig. 4 has shown the different gains spectrum that Raman amplifier obtains under different pump powers;

Fig. 5 has shown the schematic structure according to first kind of spectrum detection device of the present invention;

Fig. 6 has shown the schematic structure according to second kind of spectrum detection device of the present invention;

Fig. 7 has shown the control structure of the output spectrum of direct control Raman amplifier;

Fig. 8 has shown the control structure of control Raman amplifier+EDFA cascade spectral characteristic;

Fig. 9 has shown the loss spectra of two the PIN pipes (PIN p n junction photodiode) in first kind of spectrum detection device of the present invention;

Figure 10 has shown that slant filtering device in first kind of spectrum detection device of the present invention is to the filter effect of different spectrum;

Figure 11 has shown the pump power in first kind of spectrum detection device of the present invention and the relation of PIN1 power;

Figure 12 has shown the pump power in first kind of spectrum detection device of the present invention and the relation of PIN2 power;

Figure 13 is the control flow chart of Raman amplifier of the present invention.

Embodiment

Before embodiments of the invention are elaborated, at first introduce the principle of the gain spectral control of Raman amplifier.

The control of Raman amplifier is based on the principle of work of Raman amplifier.Raman amplifier is according to the work of the stimulated Raman scattering in the optical fiber (SRS) effect.The pump light of single wavelength can only effectively amplify the flashlight in the limited wavelength scope (approximately 40nm), is the gain that maximum is realized in the place of 13.2THz (being that wavelength is separated by about 100nm) at the difference on the frequency of flashlight and pump light.In order to realize the gain in the whole transmission bandwidth, must use the pump light of a plurality of wavelength.Such as at least two of C BAND, at least 3 of C+L BAND.We can regulate the gain of the flashlight of different wave length, the reason of Gain Adjustable that Here it is by adjusting the pump power of different wave length.It also is the intrinsic advantage of Raman amplifier.Raman amplifier with two pumping wavelengths is an example, and j wavelength signals light amplifies the back luminous power through Raman and can be expressed as follows:

${\mathrm{<figure-callout\; id="1"\; label="P\; j"\; filenames="A20041007416700222.png"\; state="\{\{state\}\}">P</figure-callout>}}_j^{}=P_j\left(0\right)+4.343\frac{g_{1j}}{A_1^{\mathrm{eff}}}(a_1{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A20041007416700222.png"\; state="\{\{state\}\}">P</figure-callout>}}_1+b_1)+4.343\frac{g_{2j}}{A_2^{\mathrm{eff}}}(a_2{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="A20041007416700231.png"\; state="\{\{state\}\}">P</figure-callout>}}_2+b_2)+{\mathrm{<figure-callout\; id="12"\; label="G"\; filenames="A20041007416700221.png,A20041007416700231.png"\; state="\{\{state\}\}">G</figure-callout>}}_{12}+G_{\&PlusMinus;}---\left(1\right)$

Here, pump power P1, P2 line taking unit (W), the signal power Pj unit of taking the logarithm (dB).Second and third is respectively the small-signal gain of 1,2 pairs of flashlights of pumping source equal sign the right; G ₁₂Be gain by pumping source interacts, pumping consumption (amplifying signal light causes) causes; G ± be because the gain that the Raman between flashlight interacts and causes.A1, b1 and a2, b2 are the parameters that characterizes RAMAN gain and pump power linear relationship, and its value is relevant with the decay and the length of optical fiber.Aeff is the net sectional area of optical fiber, and the more little then mould of Aeff field internal power density is big more, and nonlinear effect approximately obviously.The net sectional area of different pumping wavelengths is slightly different.Here pump light P1, P2 are the amounts that depends on j strongly to the gain coefficient g1 and the g2 of flashlight, just this reason we can control output spectra.Fig. 3 has shown the distribution situation of the Raman gain factor.Ordinate is a gain factor, is directly proportional with amount of gain.Horizontal ordinate is the difference on the frequency between pump light and the flashlight.

Below only be that Raman amplifier has the relational expression under the situation of two pumping wavelengths, relation between the luminous power after Raman amplifies and the pump power of Raman amplifier (being the input of Raman amplifier and the relation between the output) can derive out fully according to the amplifier self property, does not enumerate one by one at this.

Based on above analysis, control the pumping of each wavelength, can obtain different gains and gain spectral.Fig. 4 is the example that the control pump power obtains the different gains spectrum, and wherein horizontal ordinate is a signal light wavelength, and ordinate is the gain of each wavelength signals light.Fig. 4 obtains by the Raman amplifier of testing two pumping wavelengths (1427nm, 1457nm).Gain spectral under the situation that is provided with that every curve all is certain pump power.The 1427nm pump power is big more, and the short-wave signal gain of light is high more, and the 1457nm pump power is big more, and the long-wave signal gain of light is high more.The result of Fig. 4 obtains under the certain condition of control full gain, if increase the power of 1427nm and 1457nm pumping simultaneously, then curve integral body is upwards moved, otherwise then moves down.If change gain spectral into output spectra, the result who obtains is also similar.

The principle of detecting light spectrum characteristic

So far we know and can obtain different gain spectral or output spectra by the control pump power, in order to realize that controlling us automatically must construct a self feed back system to realize closed loop procedure.Feedback system cost based on OPM is too high, the present invention proposes another kind of feedback mechanism: come perception spectrum with two (or more than two) photo-detectors (PIN).A typical spectral detection light path as shown in Figure 5.It should be noted that use the device of PIN pipe as detection of optical power in the embodiment of the invention, its induction current is directly proportional with the luminous power of input.But also can use APD (avalanche effect diode) etc. to substitute, the latter is used for the miniwatt situation more, and power consumption and noise are all bigger.

In Fig. 5, at Raman amplifier have two pumping wavelengths, also can in the RAMAN of a plurality of pumping wavelengths amplifier, use this detecting structure.Detection method, feedback method and control flow are all constant, just consider the general power proportioning of length wavelength when specifically calculating pump power change amount, rather than direct length wavelength single wavelength power ratio in the literary composition.Because at present industry generally adopts the RAMAN amplifier of two wavelength, so be example with two wavelength amplifiers among the present invention.

In Fig. 5, feedback system is by two shunts, and two PIN pipes and a wave filter are realized.This part light path can be made in Raman amplifier module and the EDFA module easily, directly applies to current system.Also can make simple little module separately, place any place that needs the detecting light spectrum characteristic.We are this little module is SDM (Spectrum Detect Module).SDM can be pure passive module also, includes only shunt and wave filter, and the PIN pipe is located in the module that must control.Can simplify circuit communication like this.

Feedback system also can be a form shown in Figure 6: a plurality of wave filters are arranged here, and only by the light of part wavelength (wave band), comprehensively the power of all PIN pipes can obtain the power situation of each wave band and then learn the spectrum situation each wave filter.

According to the difference of controlled target, different control structures can be arranged.Fig. 7 has shown the control structure of the output spectrum of direct control Raman amplifier, wherein SDM is placed Raman amplifier after, be used for surveying the output spectrum of Raman amplifier, thus the spectrum property of control Raman amplifier.

Fig. 8 has shown the control structure of control Raman amplifier+EDFA cascade spectral characteristic, after wherein SDM being placed EDFA, survey the performance of EDFA output spectrum, result of detection feeds back to Raman amplifier, the control Raman amplifier to be influence the cascade performance of Raman amplifier+EDFA, thereby realizes controlling the purpose of Raman amplifier+EDFA spectral characteristic.

Certainly, the output of SDM also can feed back to EDFA, realizes the purpose of spectrum control by control EDFA.But how to adjust EDFA and change the method for spectral characteristic not within the discussion scope of present patent application.

Feedback system shown in Figure 6 obtains spectral characteristic than easy to understand by surveying each wave band power, and this texture ratio is more intuitive and reliable, but the big algorithm complexity of cost height and data volume.Feedback system shown in Figure 5 is a better scheme cheaply.Wave filter among Fig. 5 is not the passage cut-off filter, but the wave filter of inclined insert loss spectrum.This wave filter is not to select to allow the light of a part of wavelength pass through, but the light of each wavelength is had nothing in common with each other by the loss that is subjected to after it.Light behind filter loss enters PIN1, and another road detection light non-filtered device directly enters PIN2, and the loss of its each wavelength is identical.

Fig. 9 enters the loss spectra of the light of two PIN pipes with respect to the light of output port, and horizontal ordinate is a wavelength, and ordinate is loss.As shown in Figure 9, the luminous power that enters PIN1 changes with wavelength, enter PIN2 then not with wavelength variations.

Adopt above two PIN pipe how to realize the spectrographic detection function, for the ease of understanding, describe with reference to the example of Figure 10.So-called spectrum is exactly the power difference of each wavelength signals light, and the long wave of spectrum integral body and the another name of the difference power between the shortwave are the inclination of spectrum.In communication system, because the inclination that factor can influence spectrum such as is chosen in Raman effect between the flashlight and EDFA working point, the inclined degree of control spectrum is the fundamental purpose of image intensifer control.Simply, as shown in figure 10, only consider the situation of two ripples, general power all is 2mW under three kinds of situations.Under first kind of situation, smooth light is through after the wave filter, and general power is 0.6mW.Under second kind of situation, the spectrum opposite with filter attenuation spectrum vergence direction is through after the wave filter, and general power is 0.8mW.Under the third situation, the vergence direction identical spectra is 0.4mW through general power after the wave filter.This shows,, after the inclination spectral filter, can judge the inclined degree of former spectrum by the general power after the decay for the light of identical general power.

Use inclination spectral filter is actually the signal light power weighting to different wave length, is the weighted sum of each signal light power through the general power behind the wave filter, and the big more local weight that decays is more little.

PIN1＝∑w _iP _i (2)

PIN2＝∑P _i (3)

Here Pi is the signal light power of i ripple, w _i=1-mw (ATT _i), ATTi is the decay of wave filter to the i ripple, the unit of taking the logarithm, i.e. dB.Mw () is the function that quantity is converted into linear amount, mw (x)=10^ (x/10).Its inverse function is dB (), and the linearity amount is converted into quantity: dB (x)=log (x)/10.Being concerned about the conversion between mW (milliwatt) and the dBm (milli decibel) in the general light transmission, is exactly to adopt above formula, such as 1mW=0dBm, and 1000mW=30dBm.Big in last routine medium short wave decay, the long wave decay is little, so the shortwave weight is little, the long wave weight is big.

For general power necessarily is that PIN2 is many ripples flashlight of definite value, if shortwave power is higher, long wave power is on the low side, after the slant filtering device, the part that shortwave power increases is just contributed not as the negative contribution to PIN1 of the part of long wave power reduction, so PIN1 will reduce PIN1's.Otherwise PIN1 will increase.So far, by the probe value of two PIN pipes, we can know the inclination situation of current spectrum.

The shape that wave filter tilts to compose will be taken all factors into consideration the simplicity of PIN pipe performance, device cost and control procedure.The linear value of Insertion Loss is preferably linear with wavelength variations, and the controlled variable that adopts in the control procedure is only linearity like this.Be reflected on the log unit, the relation of Insertion Loss and wavelength should be a logarithmic curve.On the other hand, the Insertion Loss amount can not too greatly can not be too little, and the power that the too big then PIN of Insertion Loss receives is too little, influences sensitivity.The power difference of the too little then length of Insertion Loss wavelength is little, reduces the precision of result of detection.The Insertion Loss spectrum (see figure 9) that adopts in this example, empirical tests can realize controlling preferably the result.

We are again for the example more specifically under three wavelength situations.Three wavelength are arranged, and power is 1,1,2, adjusts the RAMAN amplifier, keeps general power, makes three wavelength power become 1.5,1,1.5, is exactly to have adjusted successfully.At this moment the power of PIN1 and PIN2 and three wavelength all are 1.33 o'clock (dreamboats) power is identical.

More specifically, such as three ripple flashlights decay back residue 10%30%50%, target power is every ripple 1.33, and then the target power of PIN1 is 1.33*0.1+1.33*0.3+1.33*0.5=1.2, and the target power of PIN2 is 1.33+1.33+1.33=4.PIN1 power is 1*0.1+1*0.3+2*0.5=1.4 at the beginning, do not meet target power, then on the basis that keeps PIN2, adjust pump power, finally obtain 1.5 1 1.5 three ripple flashlights, at this moment PIN1 power is 1.5*0.1+1*0.3+1.5*0.5=1.2, adjusts successfully.

Make one tunnel process inclination spectral filter of light signal in the above embodiment of the present invention, another road direct detection.It is to survey light to be divided into 3 the tunnel that a possible scheme is also arranged, and two-way all passes through the inclination spectral filter, and the vergence direction of two wave filters is opposite.Third Road is without wave filter.Such benefit is that degree of accuracy is higher when signal wavelength concentrates on long wave or shortwave.Also can be Third Road without the removing of wave filter, directly by the filtered photocontrol spectrum of two-way.In this scheme, only need formula (3) PIN2=∑ P _iChange to PIN2=∑ w _2iP _i, w wherein _2iBe 1 to deduct of the decay of second wave filter to the i ripple.Identical in its process and method and the foregoing description.

Here it must be noted that, realize output spectra control in this way, must know the last ripple situation of system.Not only to know and go up how many ripples, also will know and go up which ripple.Realize that this point needs webmastering software and main control software that interface is provided.Webmastering software is known current last ripple situation, is handed down to the Control Software of RAMAN amplifier by main control software, allows this software have the current information that goes up the ripple situation.Example as shown in figure 10, if the wavelength shift of two ripple flashlights, final general power also can be along with change, because attenuator is just different for the damping capacity of every ripple flashlight.But,, just can determine to export under the smooth situation target general power after the decay according to the Insertion Loss spectrum of attenuator in case determined the signal light wavelength.

The control implementation procedure of the output spectra of Raman amplifier

Adopt the light path shown in Fig. 7 (or Fig. 8) to form after the feedback system, can carry out closed-loop control Raman's output spectra.Figure 13 is the control flow chart of Raman amplifier of the present invention.Control procedure is in two steps: 1, determining of controlled quentity controlled variable desired value: for given target output spectrum, think that target reaches when what value is the probe power of PIN1 and PIN2 reach.2, how the Adjustment System parameter makes controlled quentity controlled variable reach desired value: the power by adjusting each pumping finally makes it fully near desired value to influence the probe power of PIN1 and PIN2.The realization in these two steps below is discussed respectively.

Determining of controlled quentity controlled variable desired value

The output of amplifier is the sum total of flashlight and amplified spont-aneous emission noise light (ASE) only, and general ASE power is much smaller than flashlight.Ignoring under the situation of ASE, every ripple flashlight is added up then to surveying the contribution of general power in the calculating target optical spectrum, just can obtain the expectation value of PIN1, PIN2 probe power.If consider ASE, then will add ASE power.

No matter be ride gain spectrum or output spectra, the target output of every ripple flashlight all is to determine.If the target output of i ripple flashlight is Pi_tag, ASE is ASE1 to the contribution of PIN1, and ASE is ASE2 to the contribution of PIN2, and then the target power of PIN1 and PIN2 is:

PIN1_tag＝∑(w1i*Pi_tag)+ASE1 (4)

PIN2_tag＝∑(w2i*Pi_tag)+ASE2 (5)

The ratio of w1i and the w2i power that to be i ripple flashlight detect at PIN1 and PIN2 place and the power of equipped at outlet port wherein, that is:

w1i＝Pi_pin1/Pi_out (6)

w2i＝Pi_pin2/Pi_out (7)

In fact w1i and w2i compose the amount that determines by the Insertion Loss amount of TAP and the Insertion Loss of wave filter.

Adjusting the amplifier running parameter makes controlled quentity controlled variable reach desired value

Specifically, each pump power of adjusting Raman amplifier exactly makes the power of PIN1 and PIN2 reach desired value.At first be the initial power of determining each pumping according to the desired value of controlled quentity controlled variable, power on for each pumping according to this initial power.Survey the currency of controlled quentity controlled variable, the difference of calculating and desired value is adjusted each pump power according to its difference, makes it final consistent with desired value.

By the analysis to above-mentioned formula (1), pump power (mW of unit) is linear with the relation of gain (dB of unit).We are that example experimentizes with the Raman amplifier of two pumping wavelengths, learn that by experiment the power relation of pump power and PIN1 and PIN2 also is linear, shown in Figure 11 and 12.

Can sum up following linear formula by above result:

$\left(\begin{array}{cc}{\mathrm{\&alpha;}}_{27}& {\mathrm{\&alpha;}}_{57}\\ {\mathrm{\&beta;}}_{27}& {\mathrm{\&beta;}}_{57}\end{array}\right)\left(\begin{array}{c}{P}_{27}\\ P_{57}\end{array}\right)+\left(\begin{array}{c}{C}_1\\ {\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="A20041007416700231.png"\; state="\{\{state\}\}">C</figure-callout>}}_2\end{array}\right)=\left(\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="dBPIN"\; filenames="A20041007416700222.png"\; state="\{\{state\}\}">dBPIN</figure-callout>}}_1\\ {\mathrm{dBPIN}}_2\end{array}\right)---\left(8\right)$

Then its residual quantity formula is:

$\left(\begin{array}{cc}{\mathrm{\&alpha;}}_{27}& {\mathrm{\&alpha;}}_{57}\\ {\mathrm{\&beta;}}_{27}& {\mathrm{\&beta;}}_{57}\end{array}\right)\left(\begin{array}{c}\mathrm{\&Delta;}{P}_{27}\\ \mathrm{\&Delta;}{P}_{57}\end{array}\right)=\left(\begin{array}{c}\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="dBPIN"\; filenames="A20041007416700222.png"\; state="\{\{state\}\}">dBPIN</figure-callout>}}_1\\ \mathrm{\&Delta;}{\mathrm{dBPIN}}_2\end{array}\right)---\left(9\right)$

Add up the matrix of coefficients that obtains by experimental result:

$\left(\begin{array}{cc}{\mathrm{\&alpha;}}_{27}& {\mathrm{\&alpha;}}_{57}\\ {\mathrm{\&beta;}}_{27}& {\mathrm{\&beta;}}_{57}\end{array}\right)=\left(\begin{array}{cc}0.01894& 0.02089\\ 0.01685& 0.02350\end{array}\right)---\left(10\right)$

Wherein, dBPIN1 and dBPIN2 are respectively the luminous powers that two detector PIN1 and PIN2 detect, the unit of taking the logarithm (dBm).It is linear above mentioning these two amounts and pump power, α ₂₇, β ₂₇, α ₅₇, β ₅₇, C ₁, C ₂, be exactly the coefficient of this linear relationship.Its value is by business configuration situation and the decision of optical fiber link situation.By above formula, can be by the difference of current controlled quentity controlled variable and aim parameter Calculate the change amount of pump power Constantly survey the value of PIN1 and PIN2 in system's operational process, constantly adjust the power of each pumping, system performance is met the demands all the time.

Because Raman amplifier adopts circuit optical fiber as gain media, so matrix of coefficients

Value change with the circuit situation.The value that circuit optical fiber kind, circuit Insertion Loss distribute even the slow variation of optical fiber all can influence coefficient matrix.So need to gather in real time this controlled variable in the practical application.Method is when just having started working, and gathers the value of the PIN variable power of several groups of pump power correspondences, the experiment in the similar above, but sampled point need not be so much, is example with two pumping wavelengths, gets 4 points and can calculate matrix of coefficients.Matrix of coefficients according to actual measurement carries out work in the future.For fear of the gradual influence of optical fiber state, according to the actual result of the PIN power of pump power correspondence in the control procedure, Correction and Control parameter in real time to the control result.Also can adopt default controlled variable at the beginning, omit special detection process, directly according to the real-time Correction and Control parameter of the intermediate result of control procedure.

Claims (25)

1. spectral method of detection may further comprise the steps:

At least one is set first along separate routes and one second shunt in transmission has the transmission line of light signal of n wavelength, wherein n is the integer greater than 1;

Make described at least one first light signal in along separate routes respectively by behind the wave filter with inclined insert loss spectrum, respectively the power of the light signal after the detection filter;

Directly detect the power of the light signal in second shunt;

Determine the spectrum of the described light signal that in described transmission line, transmits according to described at least one first power of the light signal of power and described second in along separate routes of light signal in along separate routes.

2. spectral method of detection according to claim 1, the inclination spectrum of wherein said wave filter is linear.

3. spectral method of detection according to claim 1, wherein said at least one first comprise along separate routes two first along separate routes, the vergence direction of the inclination spectrum of two first wave filters in along separate routes is opposite.

4. spectrum detection device is used for detecting the spectrum of the light signal with n wavelength that transmits at transmission line, and wherein n is the integer greater than 1, and this device comprises:

At least one first shunt and one second shunt are arranged on the described transmission line, are used for branch and pick out described light signal;

The wave filter with inclined insert loss spectrum that is connected with described at least one first shunt is used for corresponding light signal is carried out filtering respectively;

First power detector that is connected with described wave filter respectively is used for the power of the light signal after the detection filter;

Second power detector directly is connected with second shunt to detect the power of light signal wherein.

5. spectrum detection device according to claim 4, the inclination spectrum of wherein said wave filter is linear.

6. spectrum detection device according to claim 4, wherein said at least one first shunt comprises two first shunts, the vergence direction of the inclination spectrum of the wave filter in two first shunts is opposite.

7. spectrum detection device according to claim 4, wherein said shunt and described wave filter are arranged on one independently in the passive module, and described power detector is arranged in the device that will use its testing result.

8. spectrum detection device according to claim 4, wherein said power detector are the PIN p n junction photodiodes.

9. spectrum detection device according to claim 4, wherein said spectrum detection device is arranged in the Raman amplifier.

10. the feedback of a Raman amplifier may further comprise the steps:

According to the target output spectrum, determine the controlled quentity controlled variable desired value of Raman amplifier;

According to the controlled quentity controlled variable desired value, determine the pump power initial value and the loading of Raman amplifier;

Detect the currency of controlled quentity controlled variable;

Whether the difference of judging currency and desired value is in permissible range;

If not in permissible range, then adjust pump power and loading according to this difference.

11. feedback according to claim 10, the controlled variable of wherein using in the step of described adjustment pump power that depends on circuit is revised in real time.

12. feedback according to claim 11 was wherein carried out the step of calibrating described controlled variable before the step of described definite controlled quentity controlled variable desired value.

13. feedback according to claim 10, the light signal of wherein establishing the Raman amplifier amplification has n wavelength, and n is the integer greater than 1, and the step of the currency of described detection controlled quentity controlled variable may further comprise the steps:

At least one in having the transmission line of light signal of n wavelength, is set in transmission first along separate routes and one second shunt;

Make described at least one first light signal in along separate routes respectively by behind the wave filter with inclined insert loss spectrum, respectively the power of the light signal after the detection filter;

Directly detect the power of the light signal in second shunt;

Determine the spectrum of the described light signal that in described transmission line, transmits according to described at least one first power of the light signal of power and described second in along separate routes of light signal in along separate routes,

Wherein said each performance number is described controlled quentity controlled variable.

14. feedback according to claim 13, the inclination spectrum of wherein said wave filter is linear.

15. feedback according to claim 13, wherein said at least one first comprise along separate routes two first along separate routes, the vergence direction of the inclination spectrum of two first wave filters in along separate routes is opposite.

16. the feed back control system of a Raman amplifier comprises:

Spectrum detection device is used to detect the spectrum of the output light signal of Raman amplifier;

Control device, be used for determining the pump power initial value and the loading of Raman amplifier according to the controlled quentity controlled variable desired value, and the spectrum that detects according to spectrum detection device, whether the difference of judging controlled quentity controlled variable desired value and currency is in permissible range, if not in permissible range, then adjust the pump power and the loading of Raman amplifier according to this difference.

17. feed back control system according to claim 16 also comprises the controlled variable correcting device, is used for revising in real time the controlled variable of using when adjusting pump power that depends on circuit.

18. feed back control system according to claim 17 also comprises the controlled variable calibrating installation, is used for the described controlled variable of calibration before definite pump power initial value.

19. feed back control system according to claim 16, the light signal of wherein establishing the Raman amplifier amplification has n wavelength, and n is the integer greater than 1, and described spectrum detection device comprises:

At least one first shunt and one second shunt are arranged on the described transmission line, are used for branch and pick out described light signal;

The wave filter with inclined insert loss spectrum that is connected with described at least one first shunt is used for corresponding light signal is carried out filtering respectively;

First power detector that is connected with described wave filter respectively is used for the power of the light signal after the detection filter;

Second power detector directly is connected with second shunt to detect the power of light signal wherein.

20. feed back control system according to claim 19, the inclination spectrum of wherein said wave filter is linear.

21. feed back control system according to claim 19, wherein said at least one first shunt comprises two first shunts, and the vergence direction of the inclination spectrum of the wave filter in two first shunts is opposite.

22. an optical relay unit comprises Raman amplifier and feed back control system thereof, wherein,

Described feed back control system comprises:

Spectrum detection device is used to detect the spectrum of the output light signal of Raman amplifier;

Control device, be used for determining the pump power initial value and the loading of Raman amplifier with the controlled quentity controlled variable desired value, and the spectrum that detects according to spectrum detection device, whether the difference of judging controlled quentity controlled variable desired value and currency is in permissible range, if not in permissible range, then adjust the pump power and the loading of Raman amplifier according to this difference.

23. optical relay according to claim 22 unit wherein is connected with Erbium-Doped Fiber Amplifier (EDFA) between Raman amplifier and spectrum detection device, described control device is controlled the cascade spectral characteristic of Raman amplifier and Erbium-Doped Fiber Amplifier (EDFA).

24. according to claim 22 or 23 described optical relay unit, the light signal of wherein establishing the Raman amplifier amplification has n wavelength, n is the integer greater than 1, and described spectrum detection device comprises:

At least one first shunt and one second shunt are arranged on the described transmission line, are used for branch and pick out described light signal;

The wave filter with inclined insert loss spectrum that is connected with described at least one first shunt is used for corresponding light signal is carried out filtering respectively;

First power detector that is connected with described wave filter respectively is used for the power of the light signal after the detection filter;

Second power detector directly is connected with second shunt to detect the power of light signal wherein.

25. optical relay according to claim 24 unit, wherein said at least one first shunt comprises two first shunts, and the vergence direction of the inclination spectrum of the wave filter in two first shunts is opposite.

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