阅读说明：本技术 一种基于掺铒和拉曼放大器的调控方法及混合放大器 (Regulation and control method based on erbium-doped and Raman amplifier and hybrid amplifier ) 是由 忻向军 常天海 毛正 王光全 张琦 刘博� 田凤 姚海鹏 田清华 高然 王珏 于 2021-11-08 设计创作，主要内容包括：本发明提供一种基于掺铒和拉曼放大器的调控方法及混合放大器,该方法包括以下步骤：根据预设的参数选取区间在参数选取区间内选择参数,将参数建立为多个参数组,参数组中的参数包括拉曼泵浦功率、掺铒泵浦功率、拉曼光纤长度和掺铒光纤长度；根据拉曼泵浦功率、掺铒泵浦功率、拉曼光纤长度和掺铒光纤长度计算总增益,利用遗传算法对参数组进行迭代更新,在每次迭代更新中选取更大的总增益所对应的参数组；当完成最后一次迭代后,选取最大总增益所对应的参数组作为最终的目标参数。本申请联合拉曼光纤放大器与掺铒光纤放大器,通过遗传算法进行迭代,输出最大总增益对应的参数组,同时调整拉曼光纤放大器与掺铒光纤放大器,提高放大效果。(The invention provides an erbium-doped Raman amplifier-based regulation method and a mixed amplifier, wherein the method comprises the following steps: selecting parameters in a parameter selection interval according to a preset parameter selection interval, and establishing the parameters into a plurality of parameter groups, wherein the parameters in the parameter groups comprise Raman pumping power, erbium-doped pumping power, Raman fiber length and erbium-doped fiber length; calculating total gain according to the Raman pumping power, the erbium-doped pumping power, the Raman fiber length and the erbium-doped fiber length, performing iterative update on parameter groups by using a genetic algorithm, and selecting the parameter group corresponding to the larger total gain in each iterative update; and after the last iteration is finished, selecting the parameter group corresponding to the maximum total gain as a final target parameter. The Raman fiber amplifier and the erbium-doped fiber amplifier are combined, iteration is carried out through a genetic algorithm, a parameter group corresponding to the maximum total gain is output, and meanwhile, the Raman fiber amplifier and the erbium-doped fiber amplifier are adjusted, so that the amplification effect is improved.)

1. A regulation and control method based on erbium-doped and Raman amplifiers is characterized in that a Raman fiber amplifier and an erbium-doped fiber amplifier are in a connection state, and the output end of the erbium-doped fiber amplifier is connected with the input end of the Raman fiber amplifier, and the regulation and control method comprises the following steps:

selecting parameters in a parameter selection interval according to a preset parameter selection interval, and establishing the parameters into a plurality of parameter groups, wherein the parameters in the parameter groups comprise Raman pumping power, erbium-doped pumping power, Raman fiber length and erbium-doped fiber length;

calculating total gain according to the Raman pumping power, the erbium-doped pumping power, the Raman fiber length and the erbium-doped fiber length, performing iterative update on the parameter set by using a genetic algorithm, and selecting the parameter set corresponding to the larger total gain in each iterative update;

after the last iteration is finished, selecting a parameter group corresponding to the maximum total gain as a final target parameter;

and applying the target parameters to a Raman fiber amplifier and an erbium-doped fiber amplifier.

2. The method of claim 1, wherein the total gain is determined by a gain estimator= output power of raman fiber amplifier/input power of erbium doped fiber amplifier,

the relation between the input power and the output power of the erbium-doped fiber amplifier is obtained according to the following formula:

；

the distribution of signal power along the raman amplifier in the raman amplifier is as follows:

；

z is the length value of the Raman fiber and the value range is 0-L_RWhen z =0, the signal is, for example,inputting signal light power for a Raman amplifier; z = L_RWhen the temperature of the water is higher than the set temperature,for outputting signal optical power to the Raman amplifier, i.e.，Representing the output signal optical power of the Raman fiber amplifier;

since the output of the erbium doped fiber amplifier is connected to the input of the raman fiber amplifier, when z =0,；is the output signal optical power of the erbium-doped fiber amplifier;

i.e. the distribution of signal power along the raman amplifier after transmission through the EDFA is expressed as:

；

representing the input signal optical power of the erbium-doped fiber amplifier,the length of the erbium-doped fiber is shown,showing the absorption cross section of the erbium doped fiber at the signal frequency,the total erbium ion density is expressed in terms of,representing the emission cross-section at the frequency of the erbium-doped signal,is an erbium-doped fiberThe average value of the metastable population density of the length,representing the loss of the erbium doped fiber at the signal frequency,the gain factor of the raman fiber amplifier is shown,indicating the raman fiber loss at the raman fiber pump frequency,representing the pump input power of the raman fiber amplifier,which is indicative of the overlap factor,for the pump input power of the erbium doped fiber amplifier,is the pump wavelengthThe cross-sectional area of the fiber mode of (a),representing the input signal optical power of the raman fiber amplifier.

3. The method of claim 2,jointly calculated according to the following formula:

；

；

；

wherein the content of the first and second substances,is the input signal optical power of the erbium-doped fiber amplifier,is an erbium-doped fiber amplifier at the pumping frequencyThe absorption cross-section of (a) is,is an erbium-doped fiber amplifier at the pumping frequencyThe absorption cross-section of (a) is,is an erbium-doped fiber amplifier at the pumping frequencyThe emission cross-section of (a) is,is the pump wavelengthThe cross-sectional area of the fiber mode of (a),is a signal wavelength ofThe cross-sectional area of the fiber mode of (a),is from the energy levelTo the energy levelThe spontaneous emission lifetime of the transition is,for the pumping rate of an erbium-doped fiber amplifier,for the stimulated absorption rate of an erbium doped fiber amplifier,for the stimulated emission rate of an erbium doped fiber amplifier,for the core total erbium ion density of an erbium doped fiber amplifier,h represents the Planckian constant.

4. The method of claim 1, wherein the step of iterating the set of parameters through a genetic algorithm comprises:

presetting the number of iterations according to the cross probability of the genetic algorithmAnd probability of variationUpdating and iterating the parameter set, and stopping iteration when the iteration times reach the preset iteration times;

probability of crossingAnd probability of variationThe adjustment is made according to the following formula:

；

；

whereinIndicating the maximum total gain of all parameter sets,represents the average total gain value of the parameter set of each generation,indicating the larger overall gain value of the two parameter sets to be crossed, f indicating the overall gain of the parameter set to be mutated,andwhich represents two cross-probability values that are,andrepresenting two variation probability values.

5. The method according to any one of claims 1-4, characterized in that the method steps further comprise:

after the total gain value is calculated in each iteration, calculating a total noise coefficient according to the total gain value in each iteration;

comparing the total noise coefficient calculated in each iteration with a preset noise coefficient threshold value;

and if the total noise coefficient of the nth generation is larger than the noise coefficient threshold value, outputting the parameter group corresponding to the maximum total gain value in the (n-1) th generation as the final target parameter.

6. The method of claim 5, wherein the total noise figure is calculated according to the following equation:

；

NF is the total noise figure of the noise,as a result of the total gain, the gain,showing the gain of the erbium-doped fiber amplifier,in order to be the noise figure of the erbium-doped fiber amplifier,is the noise figure of the raman fiber amplifier.

7. The method of claim 6, wherein the noise figure of the erbium doped fiber amplifier is calculated according to the following formula:

；

representing the input signal-to-noise ratio of the erbium doped fiber amplifier,representing the output signal-to-noise ratio of the erbium doped fiber amplifier,denotes the spontaneous emission factor of the erbium-doped fiber, h denotes the planck constant, v denotes the frequency of light,representing the spontaneous emission noise bandwidth of the erbium doped fiber amplifier,representing the spontaneous radiated noise power of the erbium doped fiber amplifier.

8. The method of claim 6 or 7, wherein the noise figure of the Raman fiber amplifier is calculated according to the following formula:

；

representing the output power of the raman fiber amplifier,denotes the spontaneous emission noise power of the raman fiber amplifier, h denotes the planck constant, v denotes the frequency of light,representing the bandwidth of the electrical filter built into the raman amplifier,showing the gain of the raman fiber amplifier,representing the input signal optical power of the raman fiber amplifier,the total gain is indicated.

9. A hybrid amplifier, characterized in that it comprises a raman fiber amplifier and an erbium-doped fiber amplifier, and in that it further comprises a control unit, which is connected to both the raman fiber amplifier and the erbium-doped fiber amplifier, and which applies the method according to any one of claims 1 to 8, and which is adapted to adjust the parameters of the raman fiber amplifier and the erbium-doped fiber amplifier.

10. A transmission system comprising a wavelength division multiplexer, a transmission fiber, an optical splitter and a hybrid amplifier according to claim 9, wherein the output of the raman fiber amplifier of the hybrid amplifier is connected to the wavelength division multiplexer, the transmission fiber is connected to the wavelength division multiplexer, and the output of the wavelength division multiplexer is connected to the optical splitter.

Technical Field

The invention relates to the technical field of optical amplifiers, in particular to an erbium-doped Raman amplifier-based regulation and control method and a hybrid amplifier.

Background

In recent years, the rapid growth of new services such as big data, cloud computing, internet of things and the like has raised a serious challenge to optical transmission networks based on optical fibers and wavelength division multiplexing, and the original transmission network with fixed wavelength grid and fixed rate is required to be developed towards the direction of a grid-free variable rate high-capacity optical transmission network so as to adapt to the optical transmission requirements of different spans, differentiated bandwidths, complex topologies and the like, wherein an optical fiber amplifier is one of the indispensable devices in optical transmission, so that higher requirements are raised for key technologies such as optical fiber amplifiers and the like.

Raman Fiber Amplifier (RFA) and erbium-doped fiber amplifier (EDFA) have been widely used in the field of optical communication, the system has an increasing demand for RFA, RFA has low noise, and is suitable for long-distance optical communication signal amplification, and meanwhile, the gain medium of RFA is the ordinary transmission fiber itself, which has good compatibility with the fiber system, while EDFA has a larger noise index compared with RFA, but has a higher performance-price ratio compared with RFA in terms of signal power amplification.

However, in the prior art, most of the EDFAs and RFAs are used independently and adjusted independently, and if only the conventional EDFAs and RFAs are used in combination, the amplification effect is poor.

Disclosure of Invention

In view of the above, embodiments of the present invention provide a method for regulating and controlling a hybrid amplifier based on erbium-doped and raman amplifiers, so as to obviate or mitigate one or more of the drawbacks of the prior art.

One aspect of the present invention provides a method for controlling based on erbium-doped and raman amplifiers, wherein a raman fiber amplifier is connected to an erbium-doped fiber amplifier, and an output end of the erbium-doped fiber amplifier is connected to an input end of the raman fiber amplifier, the method comprising the steps of:

selecting parameters in a parameter selection interval according to a preset parameter selection interval, and establishing the parameters into a plurality of parameter groups, wherein the parameters in the parameter groups comprise Raman pumping power, erbium-doped pumping power, Raman fiber length and erbium-doped fiber length;

calculating total gain according to the Raman pumping power, the erbium-doped pumping power, the Raman fiber length and the erbium-doped fiber length, performing iterative update on the parameter set by using a genetic algorithm, and selecting the parameter set corresponding to the larger total gain in each iterative update;

after the last iteration is finished, selecting a parameter group corresponding to the maximum total gain as a final target parameter;

and applying the target parameters to a Raman fiber amplifier and an erbium-doped fiber amplifier.

By adopting the scheme, the Raman fiber amplifier and the erbium-doped fiber amplifier are combined to calculate the total gain, the Raman pumping power, the erbium-doped pumping power, the Raman fiber length and the erbium-doped fiber length are combined into a parameter set, the total gain corresponding to the parameter set is simultaneously calculated, the parameter set is iterated through a genetic algorithm, the parameter set corresponding to the larger total gain is output every iteration, the parameter set corresponding to the maximum total gain is finally output, and the combined Raman fiber amplifier and the erbium-doped fiber amplifier are adjusted simultaneously to improve the amplification effect.

In some embodiments of the invention, the total gain is= output power of raman fiber amplifier/input power of erbium doped fiber amplifier,

the relation between the input power and the output power of the erbium-doped fiber amplifier is obtained according to the following formula:

；

the distribution of signal power along the raman amplifier in the raman amplifier is as follows:

；

z is the length of the raman fiber, and ranges from 0-LR, when z =0,inputting signal light power for a Raman amplifier; when z = LR, the ratio of the total of the components is as low as possible,for outputting signal optical power to the Raman amplifier, i.e.，Representing the output signal optical power of the Raman fiber amplifier;

since the output of the erbium doped fiber amplifier is connected to the input of the raman fiber amplifier, when z =0,；for the output signal optical power of the erbium-doped fiber amplifier,the optical power of an input signal of the Raman fiber amplifier;

i.e. the distribution of signal power along the raman amplifier after transmission through the EDFA can be expressed as:

；

representing the input signal optical power of the erbium-doped fiber amplifier,the length of the erbium-doped fiber is shown,showing the absorption cross section of the erbium doped fiber at the signal frequency,the total erbium ion density is expressed in terms of,representing the emission cross-section at the frequency of the erbium-doped signal,is an erbium-doped fiberThe average value of the metastable population density of the length,representing the loss of the erbium doped fiber at the signal frequency,the gain factor of the raman fiber amplifier is shown,indicating the raman fiber loss at the raman fiber pump frequency,representing the pump input power of the raman fiber amplifier,which is indicative of the overlap factor,is the pump input power of the erbium doped fiber amplifier.

By adopting the scheme, the Raman pump power in the parameter group is inputErbium doped pump powerThe value of the Raman fiber length, i.e. z, the erbium-doped fiber lengthTo obtain the input signal optical power of the erbium-doped fiber amplifierAnd the output signal optical power of Raman fiber amplifierTo obtain the total gain。

In some embodiments of the present invention, the first and second electrodes are,jointly calculated according to the following formula:

；

；

；

wherein the content of the first and second substances,is the input signal optical power of the erbium-doped fiber amplifier,is doped with erbiumOptical fiber amplifier at pump frequencyThe absorption cross-section of (a) is,is an erbium-doped fiber amplifier at the pumping frequencyThe absorption cross-section of (a) is,is an erbium-doped fiber amplifier at the pumping frequencyThe emission cross-section of (a) is,is the pump wavelengthThe cross-sectional area of the fiber mode of (a),is a signal wavelength ofThe cross-sectional area of the fiber mode of (a),is from the energy levelTo the energy levelThe spontaneous emission lifetime of the transition is,pumping speed for erbium doped fiber amplifierThe ratio of the total weight of the particles,for the stimulated absorption rate of an erbium doped fiber amplifier,for the stimulated emission rate of an erbium doped fiber amplifier,h represents the planck constant for the core total erbium ion density of an erbium-doped fiber amplifier.

In some embodiments of the present invention, the first and second electrodes are,。

in some embodiments of the invention, the step of iterating the set of parameters through a genetic algorithm comprises:

presetting the number of iterations according to the cross probability of the genetic algorithmAnd probability of variationAnd updating and iterating the parameter set, and stopping iteration when the iteration times reach the preset iteration times.

In some embodiments of the invention, the cross probabilityAnd probability of variationThe adjustment is made according to the following formula:

；

；

whereinIndicating the maximum total gain of all parameter sets,represents the average total gain value of the parameter set of each generation,indicating the larger overall gain value of the two parameter sets to be crossed, f indicating the overall gain of the parameter set to be mutated,andwhich represents two cross-probability values that are,andrepresenting two variation probability values.

In some embodiments of the invention, the steps of the method further comprise:

after the total gain value is calculated in each iteration, calculating a total noise coefficient according to the total gain value in each iteration;

comparing the total noise coefficient calculated in each iteration with a preset noise coefficient threshold value;

and if the total noise coefficient of the nth generation is larger than the noise coefficient threshold value, outputting the parameter group corresponding to the maximum total gain value in the (n-1) th generation as the final target parameter.

In some embodiments of the invention, if the total noise figure of the nth generation is greater than the noise figure threshold, then the iteration is skipped.

In some embodiments of the invention, the total noise figure is calculated according to the following formula:

；

NF is the total noise figure of the noise,as a result of the total gain, the gain,showing the gain of the erbium-doped fiber amplifier,in order to be the noise figure of the erbium-doped fiber amplifier,is the noise figure of the raman fiber amplifier.

In some embodiments of the present invention, the noise figure of an erbium doped fiber amplifier is calculated according to the following formula:

；

representing the input signal-to-noise ratio of the erbium doped fiber amplifier,representing the output signal-to-noise ratio of the erbium doped fiber amplifier,denotes the spontaneous emission factor of the erbium-doped fiber, h denotes the planck constant, v denotes the frequency of light,representing spontaneous emission noise bandwidth of erbium-doped fiber amplifier，Representing the spontaneous radiated noise power of the erbium doped fiber amplifier.

In some embodiments of the invention, the noise figure of the raman fiber amplifier is calculated according to the following formula:

；

representing the output power of the raman fiber amplifier,denotes the spontaneous emission noise power of the raman fiber amplifier, h denotes the planck constant, v denotes the frequency of light,representing the bandwidth of the electrical filter built into the raman amplifier,showing the gain of the raman fiber amplifier,representing the input signal optical power of the raman fiber amplifier,the total gain is indicated.

In some embodiments of the present invention, the gain of an erbium doped fiber amplifier is calculated according to the following formula:

；

represents the signal output power of the erbium doped fiber amplifier,representing the spontaneous radiation power of the erbium-doped fiber amplifier,representing the signal input power of the erbium doped fiber amplifier.

In some embodiments of the invention, the gain of the raman fiber amplifier is calculated according to the following formula:

；

wherein the content of the first and second substances,the gain factor of the raman fiber amplifier is determined by the composition of the raman fiber core material.The pump input optical power of the raman fiber amplifier,to characterize the equivalent length of the fiber that actually produces the amplification,is the equivalent mode field area of the fiber.

The invention discloses a regulation and control method based on erbium-doped and Raman amplifiers, which is characterized in that the total gain is calculated by combining the Raman fiber amplifier and the erbium-doped fiber amplifier, the Raman pumping power, the erbium-doped pumping power, the Raman fiber length and the erbium-doped fiber length are combined into a parameter set, the total gain corresponding to the parameter set is calculated at the same time, the parameter set is iterated through a genetic algorithm, the parameter set corresponding to the larger total gain is output every iteration, the parameter set corresponding to the maximum total gain is output finally, and the combined Raman fiber amplifier and the erbium-doped fiber amplifier are adjusted at the same time, so that the amplification effect is improved.

Another aspect of the present invention provides a hybrid amplifier, which includes a raman fiber amplifier and an erbium-doped fiber amplifier, and further includes a control unit, which is connected to both the raman fiber amplifier and the erbium-doped fiber amplifier, and which applies the method as described above, and which is configured to adjust parameters of the raman fiber amplifier and the erbium-doped fiber amplifier.

Another aspect of the present invention further provides a transmission system, which includes a wavelength division multiplexer, a transmission fiber, an optical splitter, and the hybrid amplifier, wherein an output end of the raman fiber amplifier in the hybrid amplifier is connected to the wavelength division multiplexer, the transmission fiber is connected to the wavelength division multiplexer, and an output end of the wavelength division multiplexer is connected to the optical splitter.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

It will be appreciated by those skilled in the art that the objects and advantages that can be achieved with the present invention are not limited to the specific details set forth above, and that these and other objects that can be achieved with the present invention will be more clearly understood from the detailed description that follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention.

FIG. 1 is a schematic diagram of a first embodiment of the erbium-doped and Raman amplifier-based modulation method of the present invention;

FIG. 2 is a schematic diagram of a second embodiment of the erbium-doped and Raman amplifier-based modulation method of the present invention;

FIG. 3 is a schematic diagram of a third embodiment of the erbium-doped and Raman amplifier-based modulation method of the present invention;

FIG. 4 is a schematic diagram of a transmission system according to the present invention;

FIG. 5 is a diagram of gain and noise figure spectra according to the present invention;

fig. 6 is a schematic diagram of a fourth embodiment of the modulation method based on erbium-doped and raman amplifiers of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the scheme according to the present invention are shown in the drawings, and other details not so relevant to the present invention are omitted.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, elements, steps or components, but does not preclude the presence or addition of one or more other features, elements, steps or components.

It is also noted herein that the term "coupled," if not specifically stated, may refer herein to not only a direct connection, but also an indirect connection in which an intermediate is present.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or similar parts, or the same or similar steps.

As shown in fig. 1, an aspect of the present invention provides a method for regulating and controlling based on erbium-doped fiber and raman amplifier, where the raman amplifier is connected to an erbium-doped fiber amplifier, and an output end of the erbium-doped fiber amplifier is connected to an input end of the raman amplifier, the method comprising the following steps:

s100, selecting parameters in a parameter selection interval according to a preset parameter selection interval, and establishing the parameters into a plurality of parameter groups, wherein the parameters in the parameter groups comprise Raman pump power, erbium-doped pump power, Raman fiber length and erbium-doped fiber length;

in some embodiments of the present invention, the data of the parameter selection interval may be as shown in the following table:

s200, calculating total gain according to the Raman pumping power, the erbium-doped pumping power, the Raman fiber length and the erbium-doped fiber length, performing iterative updating on the parameter group by using a genetic algorithm, and selecting the parameter group corresponding to the larger total gain in each iterative updating;

in some embodiments of the present invention, a plurality of parameter sets are selected in the parameter selection interval, where each parameter set includes parameters of the raman pump power, the erbium-doped pump power, the raman fiber length, and the erbium-doped fiber length.

In some embodiments of the present invention, 150 parameters may be selected from the group of parameters.

In some embodiments of the present invention, the number of iterations of the genetic algorithm is preset, and the number of iterations may be 55 generations.

And S300, after the last iteration is finished, selecting the parameter group corresponding to the maximum total gain as a final target parameter.

In some embodiments of the present invention, if the iteration number is 55 generations, the total gain of 150 parameter sets of 55 generations respectively is selected, the parameter set corresponding to the maximum total gain is selected, and the raman pump power, the erbium-doped pump power, the raman fiber length, and the erbium-doped fiber length in the parameter set are extracted as final target parameters.

And applying the target parameters to a Raman fiber amplifier and an erbium-doped fiber amplifier.

In some embodiments of the invention, the raman pump power, the raman fiber length, and the erbium doped fiber length and the erbium doped pump power of the target parameters are applied to a raman fiber amplifier.

And pump lasers are arranged in the Raman fiber amplifier and the erbium-doped fiber amplifier.

By adopting the scheme, the Raman fiber amplifier and the erbium-doped fiber amplifier are combined to calculate the total gain, the Raman pumping power, the erbium-doped pumping power, the Raman fiber length and the erbium-doped fiber length are combined into a parameter set, the total gain corresponding to the parameter set is simultaneously calculated, the parameter set is iterated through a genetic algorithm, the parameter set corresponding to the larger total gain is output every iteration, the parameter set corresponding to the maximum total gain is finally output, and the combined Raman fiber amplifier and the erbium-doped fiber amplifier are adjusted simultaneously to improve the amplification effect.

In some embodiments of the invention, the total gain is= output power of raman fiber amplifier/input power of erbium doped fiber amplifier,

the relation between the input power and the output power of the erbium-doped fiber amplifier is obtained according to the following formula:

；

the distribution of signal power along the raman amplifier in the raman amplifier is as follows:

；

z is the length value of the Raman fiber and the value range is 0-L_RWhen z =0, the signal is, for example,inputting signal light power for a Raman amplifier; z = L_RWhen the temperature of the water is higher than the set temperature,for outputting signal optical power to the Raman amplifier, i.e.，Representing the output signal optical power of the Raman fiber amplifier;

since the output of the erbium doped fiber amplifier is connected to the input of the raman fiber amplifier, when z =0,；for the output signal optical power of the erbium-doped fiber amplifier,the optical power of an input signal of the Raman fiber amplifier;

i.e. the distribution of signal power along the raman amplifier after transmission through the EDFA can be expressed as:

；

representing the input signal optical power of the erbium-doped fiber amplifier,the length of the erbium-doped fiber is shown,showing the absorption cross section of the erbium doped fiber at the signal frequency,the total erbium ion density is expressed in terms of,representing the emission cross-section at the frequency of the erbium-doped signal,is an erbium-doped fiberThe average value of the metastable population density of the length,representing the loss of the erbium doped fiber at the signal frequency,the gain factor of the raman fiber amplifier is shown,indicating the raman fiber loss at the raman fiber pump frequency,representing the pump input power of the raman fiber amplifier,which is indicative of the overlap factor,is the pump input power of the erbium doped fiber amplifier.

Taking the coverage bandwidth from 190.6 to 193.1THz as an example, the values of the parameters in the above formula can be shown as the following table:

in some embodiments of the present invention, the first and second electrodes are,jointly calculated according to the following formula:

；

；

；

wherein the content of the first and second substances,is the input signal optical power of the erbium-doped fiber amplifier,is an erbium-doped fiber amplifier at the pumping frequencyThe absorption cross-section of (a) is,is an erbium-doped fiber amplifier at the pumping frequencyThe absorption cross-section of (a) is,is an erbium-doped fiber amplifier at the pumping frequencyThe emission cross-section of (a) is,is the pump wavelengthThe cross-sectional area of the fiber mode of (a),is a signal wavelength ofThe cross-sectional area of the fiber mode of (a),is from the energy levelTo the energy levelThe spontaneous emission lifetime of the transition is,for the pumping rate of an erbium-doped fiber amplifier,for the stimulated absorption rate of an erbium doped fiber amplifier,for the stimulated emission rate of an erbium doped fiber amplifier,h represents the planck constant for the core total erbium ion density of an erbium-doped fiber amplifier.

In some embodiments of the present invention, the first and second electrodes are,。

in some embodiments of the present invention, the first and second electrodes are,

；

wherein the content of the first and second substances,in order to achieve the ground state population density,for the density of the metastable state population,is the EDFA core total erbium ion density.

By adopting the scheme, the total gain corresponding to the parameter group, namely the Raman pump power can be obtained by combining the plurality of formulasErbium doped pump powerLength of Raman fiberAnd the length z of the erbium-doped fiber, and extracting the parameter group with the maximum total gain to obtain the Raman pump power corresponding to the maximum total gainErbium doped pump powerLength of Raman fiberAnd length of erbium doped fiber。

As shown in fig. 6, in some embodiments of the present invention, the step of iterating the set of parameters through a genetic algorithm comprises:

presetting the number of iterations according to the cross probability of the genetic algorithmAnd probability of variationAnd updating and iterating the parameter set, and stopping iteration when the iteration times reach the preset iteration times.

In some embodiments of the invention, the cross probabilityAnd probability of variationThe adjustment is made according to the following formula:

；

；

whereinIndicating the maximum total gain of all parameter sets,represents the average total gain value of the parameter set of each generation,indicating the larger overall gain value of the two parameter sets to be crossed, f indicating the overall gain of the parameter set to be mutated,andwhich represents two cross-probability values that are,andrepresenting two variation probability values.

In some embodiments of the invention, it is possible to have=0.9，=0.6，=0.1，=0.001。

In some embodiments of the present invention, the selection of crossover probability and mutation probability in the parameters of the genetic algorithm is key to influence the behavior and performance of the genetic algorithm, directly influencing the convergence of the algorithm; the application is corresponding to lower for individuals with total gain higher than the average adaptive value of the populationAndthe solution is protected into the next generation; while individuals with lower than average overall gain correspond to higherAndthe solution is eliminated.

As shown in fig. 2 and 3, in some embodiments of the present invention, the method further includes S400, iteratively skipping, where the iteratively skipping includes S410, skipping noise, and the step of skipping noise is:

after the total gain value is calculated in each iteration, calculating a total noise coefficient according to the total gain value in each iteration;

comparing the total noise coefficient calculated in each iteration with a preset noise coefficient threshold value;

and if the total noise coefficient of the nth generation is larger than the noise coefficient threshold value, outputting the parameter group corresponding to the maximum total gain value in the (n-1) th generation as the final target parameter.

By adopting the scheme, the interference of noise is considered on the premise of considering better gain of the amplifier, and the propagation of signals is easily influenced if the noise is too large, so that the noise coefficient threshold is preset, and when the total noise coefficient of the nth generation is greater than the noise coefficient threshold, iteration is skipped, and the noise interference is reduced while the gain is ensured.

In some embodiments of the invention, if the total noise figure of the nth generation is greater than the noise figure threshold, then the iteration is skipped.

In some embodiments of the invention, the total noise figure is calculated according to the following formula:

；

NF is the total noise figure of the noise,as a result of the total gain, the gain,showing the gain of the erbium-doped fiber amplifier,in order to be the noise figure of the erbium-doped fiber amplifier,is the noise figure of the raman fiber amplifier.

In some embodiments of the present invention, the noise figure of an erbium doped fiber amplifier is calculated according to the following formula:

；

representing the input signal-to-noise ratio of the erbium doped fiber amplifier,representing the output signal-to-noise ratio of the erbium doped fiber amplifier,denotes the spontaneous emission factor of the erbium-doped fiber, h denotes the planck constant, v denotes the frequency of light,representing the spontaneous emission noise bandwidth of the erbium doped fiber amplifier,representing the spontaneous radiated noise power of the erbium doped fiber amplifier.

In some embodiments of the invention, the noise figure of the raman fiber amplifier is calculated according to the following formula:

；

representing the output power of the raman fiber amplifier,denotes the spontaneous radiation noise power of the Raman fiber amplifier, h denotes the Planckian constantThe quantity, v, represents the frequency of the light,representing the bandwidth of the electrical filter built into the raman amplifier,showing the gain of the raman fiber amplifier,representing the input signal optical power of the raman fiber amplifier,the total gain is indicated.

In some embodiments of the present invention, the gain of an erbium doped fiber amplifier is calculated according to the following formula:

；

represents the signal output power of the erbium doped fiber amplifier,representing the spontaneous radiation power of the erbium-doped fiber amplifier,representing the signal input power of the erbium doped fiber amplifier.

In some embodiments of the invention, the gain of the raman fiber amplifier is calculated according to the following formula:

；

wherein the content of the first and second substances,the gain factor of the raman fiber amplifier is determined by the composition of the raman fiber core material.The pump input optical power of the raman fiber amplifier,to characterize the equivalent length of the fiber that actually produces the amplification,is the equivalent mode field area of the fiber.

As shown in fig. 2 and 3, in some embodiments of the present invention, the iterative skipping further includes S420, skipping a desired gain, where the step of skipping a desired gain is:

presetting an expected gain, and comparing the total gain calculated by each iteration with the expected gain;

and if the total gain value of at least one group of parameter groups is larger than the expected gain in the multiple parameter groups of the Mth generation, comparing the total gain values corresponding to the multiple parameter groups of the Mth generation, selecting the parameter group corresponding to the maximum total gain in the multiple parameter groups of the Mth generation, and outputting the parameters in the parameter group as the expected parameters.

By adopting the scheme, in actual application, the maximum gain is not needed possibly, but can be met when the gain reaches a certain value, and when the situation occurs, the parameter group corresponding to the maximum total gain in the multiple parameter groups of the Mth generation meeting the expected gain is directly output, so that the calculation amount is reduced, and the parameter output efficiency is improved.

The invention discloses a regulation and control method based on erbium-doped and Raman amplifiers, which combines a Raman fiber amplifier and an erbium-doped fiber amplifier to calculate total gain, combines Raman pumping power, erbium-doped pumping power, Raman fiber length and erbium-doped fiber length into parameter groups, calculates total gain corresponding to the parameter groups at the same time, iterates the parameter groups through a genetic algorithm, outputs the parameter groups corresponding to larger total gain every iteration, outputs the parameter groups corresponding to the maximum total gain at last, and adjusts the combined Raman fiber amplifier and the erbium-doped fiber amplifier to improve amplification effect.

Another aspect of the present invention provides a hybrid amplifier, as shown in fig. 4, which includes a raman fiber amplifier and an erbium-doped fiber amplifier, and a control unit, which is connected to both the raman fiber amplifier and the erbium-doped fiber amplifier, and applies the method as described above, and is used for adjusting parameters of the raman fiber amplifier and the erbium-doped fiber amplifier.

Another aspect of the present invention also provides a transmission system, as shown in fig. 4, the transmission system includes a wavelength division multiplexer, a transmission fiber, an optical splitter, and the hybrid amplifier, in which the output end of the raman fiber amplifier is connected to the wavelength division multiplexer, the transmission fiber is connected to the wavelength division multiplexer, and the output end of the wavelength division multiplexer is connected to the optical splitter.

The wavelength division multiplexer described in the present application uses a flexible grid optical network, and a fixed grid of a 50GHz spectrum gap is generally used in a conventional wavelength division multiplexing WDM optical network to carry services, if the fixed grid is used to carry transmission of ultra-high speed signals, or serious spectrum resource waste is caused. Flexible-grid optical networks reduce the pitch of the grids and allow one optical modulation signal to simultaneously span multiple micro-grids. However, in different distance transmission, due to the influence of factors such as dispersion, loss, nonlinear effect of the optical fiber and loss of the optical device, the flexible grid optical network cannot be used by the optical amplifier.

The combination of the Raman fiber amplifier and the erbium-doped fiber amplifier can automatically realize the optimal distribution of the grid signals, reduce the gain fluctuation and have high flexibility.

If it is desired to reduce the channel spacing in a flexible grid fiber communication system, important parameters, such as the raman fiber length, erbium doped fiber length, and pump power mentioned in this application, need to be optimized before deploying the hybrid amplifier.

In optical networks, it is often desirable to use the optical wavelength spectrum to carry a wide variety of services. In this process, some spectral fragmentation is inevitably present, which is disadvantageous for the whole optical network, because it reduces the spectral efficiency. The flexible grid optical network restricts the spectrum consistency, namely the same subcarrier band must be used in the transmission process, and also restricts the spectrum continuity, namely the service allocation must be continuous spectrum subcarriers in the transmission process, and the third restriction is the spectrum non-aliasing property, which mainly means that different frequency bands are used for different services, and the condition that one frequency band is used for two services at the same time cannot occur. Compared with a wavelength division multiplexing WDM optical network, the flexible grid optical network is more flexible due to smaller subcarrier particles, can be more suitable for various services with different particle sizes, and is higher in frequency use efficiency.

As shown in FIG. 6, the total gain in the invention is the fitness value of the genetic algorithm, the competition selection of the genetic algorithm selects a random value for chromosomes according to a small probability, and new chromosome pairs are obtained from the selected chromosomes through a crossing method. These newly generated chromosomes form a temporary new population, which is replaced after mutation operations are performed on each new chromosome. Finally, a new improved population, i.e. the set of parameters finally obtained in the present application, is obtained.

The Raman fiber amplifier and the erbium-doped fiber amplifier are combined, and the control unit is used for controlling the Raman fiber amplifier and the erbium-doped fiber amplifier to adjust the gain according to the expected amplification requirement. By using the mixed amplification scheme, a complete gain and noise phase coefficient theoretical model can be established by analyzing important parameters such as the length of the erbium-doped optical fiber, the length of the Raman optical fiber and the pumping power thereof, and the optimized adaptive genetic algorithm is utilized to iteratively optimize a gain spectrum and a noise coefficient spectrum so as to obtain the maximum gain and reduce the noise of the amplifier, thereby realizing the C + L waveband broadband amplification scheme suitable for large-capacity ultra-long distance transmission.

As shown in fig. 5, in some embodiments of the present invention, the present application can output gain and noise figure spectra according to different input signals by setting an amplifier according to the output parameter set.

The gain flatness is realized by optimizing the length of the EDFA and the RFA, the pump power and other parameters. The hybrid amplifier can automatically realize the optimal distribution of the grid signals, reduces the gain fluctuation and has high flexibility.

In accordance with the above method, the present invention also provides a regulation system based on erbium-doped and raman amplifiers, which comprises a computer device including a processor and a memory, wherein the memory stores computer instructions, and the processor is configured to execute the computer instructions stored in the memory, and when the computer instructions are executed by the processor, the apparatus/system implements the steps of the method as described above.

Embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the steps of the aforementioned erbium-doped and raman amplifier-based modulation method. The computer readable storage medium may be a tangible storage medium such as Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, floppy disks, hard disks, removable storage disks, CD-ROMs, or any other form of storage medium known in the art.

Those of ordinary skill in the art will appreciate that the various illustrative components, systems, and methods described in connection with the embodiments disclosed herein may be implemented as hardware, software, or combinations of both. Whether this is done in hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. When implemented in hardware, it may be, for example, an electronic circuit, an Application Specific Integrated Circuit (ASIC), suitable firmware, plug-in, function card, or the like. When implemented in software, the elements of the invention are the programs or code segments used to perform the required tasks. The program or code segments may be stored in a machine-readable medium or transmitted by a data signal carried in a carrier wave over a transmission medium or a communication link.

It is to be understood that the invention is not limited to the specific arrangements and instrumentality described above and shown in the drawings. A detailed description of known methods is omitted herein for the sake of brevity. In the above embodiments, several specific steps are described and shown as examples. However, the method processes of the present invention are not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications and additions or change the order between the steps after comprehending the spirit of the present invention.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments in the present invention.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made to the embodiment of the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.