Patent Description:
Fiber amplifiers are widely used in the fields of optical communications and optical sensing technologies. The fiber amplifiers include a semiconductor optical amplifier, a rare-earth-doped fiber amplifier, and the like. The rare-earth-doped fiber amplifier, for example, an erbium-doped fiber amplifier (erbium-doped fiber amplifier, EDFA), is an essential device in a wavelength division multiplexing (wavelength division multiplexing, WDM) system, and is used to amplify an optical signal transmitted in the system. However, a gain curve of this type of fiber amplifier is not flat. In other words, when optical signals with different wavelengths pass through this type of fiber amplifier, gains of the different wavelengths are different. A wavelength with a low gain corresponds to low optical signal power. Consequently, this increases a corresponding bit error rate and even affects transmission performance of the entire system. Therefore, how to adjust the gain curve of the fiber amplifier becomes a major technical problem.

Currently, the fiber amplifier is equipped with a built-in gain flattening filter (gain flattening filter, GFF), and an insertion loss curve of the GFF interacts with the gain curve of the fiber amplifier, to adjust the gain curve of the fiber amplifier. This solution can only adjust the gain curve of the fiber amplifier as a whole, and adjustment precision is not ideal. <CIT> discloses an optical device having a dynamic gain adjusting filter with dynamically-adjusting spectral gain characteristics. The dynamic gain flattening filter includes one or more semiconductor optical amplifier. The dynamic gain flattening filter may operate to compensate for gain peaks in the amplifier arrangement. <CIT> discloses a broadband optical amplifier that can provide a constant amplifier gain profile, correct for ASE noise, and minimize gain tilt by dynamically controlling different stages of the amplifier through a combination of gain, loss, and power control of each stage depending on input and the desired output level. D2 also fails to disclose the above mentioned distinguishing feature. <CIT> discloses an apparatus for reducing such gain profile variations, which monitors optical signal perturbations and reacts by adjusting pump powers of the amplifiers and, or fast variable optical attenuator according to a predetermined function stored in the form of constants in controller's memory. <CIT> disclose a control apparatus that includes a light monitoring unit for dividing a signal wavelength band into at least a band, in which output light power of an optical amplifier tends to decrease at an decrease in the number of signal wavelengths and a band including a gain deviation band, and for monitoring inputted light power for the individual divided bands, calculation unit for obtaining the number of signal wavelengths in the individual divided bands based on a monitor result, and a target gain correction unit for correcting a target gain based on a result of the calculation.

The present invention is defined by the apparatus of independent claim <NUM> and by the method of independent claim <NUM>. This section will be modified accordingly after the scope of the claims is determined.

In the following, parts of the description and drawing referring to embodiments, which are not covered by the claims are not presented as embodiments of the invention, but as examples useful for understanding the invention.

Embodiments of this application disclose a fiber amplifier and a gain adjustment method for the fiber amplifier, so that power adjustment can be performed on each wavelength of the fiber amplifier, and adjustment precision of a gain curve of the fiber amplifier reaches a wavelength level. This improves adjustment precision of the gain curve of the fiber amplifier. According to a first aspect, an embodiment of this application discloses a fiber amplifier, including a first power amplifier, a wavelength level adjuster, and a controller, where the first power amplifier and the wavelength level adjuster are sequentially connected, or the wavelength level adjuster and the first power amplifier are sequentially connected; the controller includes a first input end and a control output end, where the first input end is configured to receive an input optical signal of the fiber amplifier, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster; and the wavelength level adjuster is configured to perform power adjustment on each wavelength based on the adjustment control signal.

In this embodiment of this application, the controller may obtain the first amplification control signal and the adjustment control signal through calculation based on the input optical signal received by the first input end. The adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength. In this way, single-wavelength gain adjustment is implemented on a gain curve of the fiber amplifier, and adjustment precision of the gain curve of the fiber amplifier is improved.

With reference to the first aspect, in a first optional implementation, the controller includes a first storage module and a first calculation module, where the first storage module is configured to store a gain characteristic parameter of the first power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, and information about target output optical power of the fiber amplifier; and the first calculation module is configured to obtain the first amplification control signal and the adjustment control signal through calculation based on the content stored by the first storage module and optical power of each wavelength of the input optical signal of the fiber amplifier.

With reference to the first optional implementation of the first aspect, in a second optional implementation of the first aspect, the controller may further include a second input end, where the second input end is configured to receive an output optical signal of the fiber amplifier; the first calculation module is further configured to obtain a second amplification control signal and a secondary adjustment control signal through calculation based on the content stored by the first storage module and optical power of each wavelength of the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold; the control output end is further configured to output the second amplification control signal to the first power amplifier, and output the secondary adjustment control signal to the wavelength level adjuster; and the wavelength level adjuster is further configured to perform power adjustment on each wavelength based on the secondary adjustment control signal.

Compared with the first optional implementation of the first aspect, the second input end is added in this implementation. The first calculation module may obtain the second amplification control signal and the secondary adjustment control signal through calculation based on the optical power of each wavelength of the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold. The secondary adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength again, until an absolute value of a difference between power of the output optical signal and the target output optical power is less than the secondary calculation threshold, so that the power of the output optical signal is closer to the target output optical power. This improves adjustment accuracy of the gain curve of the fiber amplifier.

With reference to the first aspect, in a third optional implementation, the fiber amplifier further includes a second power amplifier, and the first power amplifier, the wavelength level adjuster, and the second power amplifier are sequentially connected; and the control output end is further configured to output a second amplification control signal to the second power amplifier.

In this implementation, the first power amplifier and the second power amplifier may be respectively used as a preamplifier and a power amplifier, and cooperate with the wavelength level adjuster to adjust the gain curve of the fiber amplifier.

With reference to the third optional implementation of the first aspect, in a fourth optional implementation of the first aspect, the controller includes a second storage module and a second calculation module, where the second storage module is configured to store gain characteristic parameters of the first power amplifier and the second power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, and target output optical power of the fiber amplifier; and the second calculation module is configured to obtain the first amplification control signal, the second amplification control signal, and the adjustment control signal through calculation based on the content stored by the second storage module and optical power of each wavelength of the input optical signal of the fiber amplifier.

In this implementation, the first power amplifier and the second power amplifier amplify optical power of different wavelengths based on the first amplification control signal and the second amplification control signal, and the wavelength level adjuster performs power insertion loss on the different wavelengths based on the adjustment control signal. Therefore, the first power amplifier, the second power amplifier, and the wavelength level adjuster interact with each other to adjust the gain curve of the fiber amplifier.

With reference to the fourth optional implementation of the first aspect, in a fifth optional implementation of the first aspect, the controller may further include a second input end, where the second input end is configured to receive an output optical signal of the fiber amplifier; the second calculation module is further configured to obtain a third amplification control signal, a fourth amplification control signal, and a secondary adjustment control signal through calculation based on the content stored by the second storage module and optical power of each wavelength of the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold; the control output end is further configured to output the third amplification control signal to the first power amplifier, output the fourth amplification control signal to the second power amplifier, and output the secondary adjustment control signal to the wavelength level adjuster; and the wavelength level adjuster is further configured to perform power adjustment on each wavelength based on the secondary adjustment control signal.

Compared with the fourth optional implementation of the first aspect, the second input end is added in this implementation. The second calculation module may obtain the third amplification control signal, the fourth amplification control signal, and the secondary adjustment control signal through calculation based on the optical power of each wavelength of the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold. The secondary adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength again, until an absolute value of a difference between power of the output optical signal and the target output optical power is less than the secondary calculation threshold, so that the power of the output optical signal is closer to the target output optical power. This improves adjustment accuracy of the gain curve of the fiber amplifier.

With reference to any one of the first aspect and the first to the fifth optional implementations of the first aspect, in a sixth optional implementation of the first aspect, the wavelength level adjuster includes a dispersion module, a wavelength level insertion loss adjustment module, and an aggregation module, where the dispersion module, the wavelength level insertion loss adjustment module, and the aggregation module are sequentially connected; the dispersion module is configured to perform spatial separation on a multi-wavelength optical signal; the aggregation module is configured to perform spatial aggregation on the multi-wavelength optical signal; and the wavelength level insertion loss adjustment module is configured to perform power adjustment on each wavelength based on the adjustment control signal.

In this implementation, the dispersion module performs space separation on the multi-wavelength optical signal, which facilitates power adjustment of each wavelength by the wavelength level adjuster, and the aggregation module may re-aggregate a separated optical signal, which facilitates subsequent transmission.

With reference to the sixth optional implementation of the first aspect, in a seventh optional implementation of the first aspect, the wavelength level insertion loss adjustment module is a liquid crystal on silicon LCOS chip, a micro-electro-mechanical systems MEMS element, or a liquid crystal LC element.

With reference to the sixth optional implementation of the first aspect, in an eighth optional implementation of the first aspect, the wavelength level adjuster further includes a first beam shaping module and a second beam shaping module, and the first beam shaping module, the dispersion module, the wavelength level insertion loss adjustment module, the aggregation module, and the second beam shaping module are sequentially connected; and the first beam shaping module and the second beam shaping module are configured to perform beam focusing and beam collimation.

According to a second aspect, an embodiment of this application discloses a gain adjustment method for a fiber amplifier, where the method is applied to the fiber amplifier disclosed in any one of the first aspect, or the second optional implementation of the first aspect, or the third optional implementation of the first aspect, or the fourth optional implementation of the first aspect, and the method includes: receiving an input optical signal of the fiber amplifier; obtaining a first amplification control signal and an adjustment control signal through calculation based on the input optical signal of the fiber amplifier, where the adjustment control signal is used to control the wavelength level adjuster to perform power adjustment on each wavelength; and outputting the first amplification control signal to the first power amplifier, and outputting the adjustment control signal to the wavelength level adjuster.

In this embodiment, the adjustment control signal obtained through calculation based on the input optical signal of the fiber amplifier may control the wavelength level adjuster to perform power adjustment on each wavelength. In this way, single-wavelength gain adjustment is implemented on a gain curve of the fiber amplifier, and adjustment precision of the gain curve of the fiber amplifier is improved.

With reference to the second aspect, in a first optional implementation, the obtaining a first amplification control signal and an adjustment control signal through calculation based on optical power of each wavelength of the input optical signal of the fiber amplifier includes: obtaining the first amplification control signal and the adjustment control signal through calculation based on a gain characteristic parameter of the first power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, target output optical power of the fiber amplifier, and the input optical signal of the fiber amplifier.

With reference to the first optional implementation of the second aspect, in a second optional implementation of the second aspect, after the outputting the first amplification control signal to the first power amplifier, and outputting the adjustment control signal to the wavelength level adjuster, the method further includes: receiving an output optical signal of the fiber amplifier; obtaining a second amplification control signal and a secondary adjustment control signal through calculation based on the gain characteristic parameter of the first power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, the target output optical power of the fiber amplifier, and optical power of each wavelength of the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold; and outputting the second amplification control signal to the first power amplifier, and outputting the secondary adjustment control signal to the wavelength level adjuster.

In this implementation, the second amplification control signal and the secondary adjustment control signal are obtained through calculation based on the optical power of each wavelength of the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold. The secondary adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength again, until an absolute value of a difference between power of the output optical signal and the target output optical power is less than the secondary calculation threshold, so that the power of the output optical signal is closer to the target output optical power. This improves adjustment accuracy of the gain curve of the fiber amplifier.

With reference to the second aspect, in a third optional implementation, the method is applied to the fiber amplifier disclosed in the first optional implementation of the first aspect, and the method further includes: obtaining a second amplification control signal through calculation based on the optical power of each wavelength of the input optical signal of the fiber amplifier; and outputting the second amplification control signal to the second power amplifier.

In this implementation, the first power amplifier and the second power amplifier amplify optical power of different wavelengths respectively based on the first amplification control signal and the second amplification control signal.

With reference to the third optional implementation of the second aspect, in a fourth optional implementation of the second aspect, the obtaining a first amplification control signal and an adjustment control signal through calculation based on optical power of each wavelength of the input optical signal of the fiber amplifier, and the obtaining a second amplification control signal through calculation based on the optical power of each wavelength of the input optical signal of the fiber amplifier include: obtaining the first amplification control signal, the second amplification control signal, and the adjustment control signal through calculation based on gain characteristic parameters of the first power amplifier and the second power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, target output optical power of the fiber amplifier, and the optical power of each wavelength of the input optical signal of the fiber amplifier.

In this implementation, the first amplification control signal and the second amplification control signal respectively control the first power amplifier and the second power amplifier to amplify optical power of different wavelengths, and the adjustment control signal controls the wavelength level adjuster to perform power insertion loss on the different wavelengths based on the adjustment control signal. Therefore, the first power amplifier, the second power amplifier, and the wavelength level adjuster interact with each other to adjust the gain curve of the fiber amplifier.

With reference to the fourth optional implementation of the second aspect, in a fifth optional implementation of the second aspect, after the outputting the first amplification control signal to the first power amplifier, and outputting the adjustment control signal to the wavelength level adjuster, and the outputting the second amplification control signal to the second power amplifier, the method further includes: receiving an output optical signal of the fiber amplifier; obtaining a third amplification control signal, a fourth amplification control signal, and a secondary adjustment control signal through calculation based on the gain characteristic parameters of the first power amplifier and the second power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, the target output optical power of the fiber amplifier, and optical power of each wavelength of the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold; and outputting the third amplification control signal to the first power amplifier, outputting the fourth amplification control signal to the second power amplifier, and outputting the secondary adjustment control signal to the wavelength level adjuster.

In this implementation, the third amplification control signal, the fourth amplification control signal, and the secondary adjustment control signal are obtained through calculation based on the optical power of each wavelength of the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold. The secondary adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength again, until an absolute value of a difference between power of the output optical signal and the target output optical power is less than the secondary calculation threshold, so that the power of the output optical signal is closer to the target output optical power. This improves adjustment accuracy of the gain curve of the fiber amplifier.

The following examples are not according to the invention and are present for illustration purposed only. This application is mainly specific to a rare-earth-doped fiber amplifier, for example, an EDFA. A person skilled in the art may learn that, with development of technologies, technologies in this application are also applicable to another rare-earth-doped fiber amplifier that is being developed or to be developed.

Currently, a fiber amplifier is equipped with a built-in gain flattening filter (gain flattening filter, GFF), and an insertion loss curve of the GFF is applied to optical power of each wavelength of the fiber amplifier, so that gains corresponding to different wavelengths of the fiber amplifier are attenuated to some extent. In this way, a gain curve of the fiber amplifier can be adjusted. However, the gain curve of the fiber amplifier can only be adjusted as a whole in such an adjustment manner, and adjustment precision of the gain curve is not ideal.

To ensure that adjustment precision of the gain curve of the fiber amplifier reaches a wavelength level, the embodiments of this application disclose a fiber amplifier and a gain adjustment method for the fiber amplifier. Details are separately described below.

<FIG> is a schematic structural diagram of a fiber amplifier according to an embodiment of this application. It can be learned from <FIG> that the fiber amplifier includes a first power amplifier <NUM>, a wavelength level adjuster <NUM>, and a controller <NUM>. The first power amplifier <NUM> and the wavelength level adjuster <NUM> are sequentially connected, where an input end of the first power amplifier is an input end of the fiber amplifier, and an output end of the wavelength level adjuster is an output end of the fiber amplifier. The controller includes a first input end I1 and a control output end O, where the first input end I1 is configured to receive an input optical signal of the fiber amplifier, and the control output end O is configured to output a first amplification control signal to the first power amplifier <NUM>, and output an adjustment control signal to the wavelength level adjuster <NUM>. The wavelength level adjuster <NUM> is configured to perform power adjustment on each wavelength based on the adjustment control signal.

In this embodiment, positions of the first power amplifier <NUM> and the wavelength level adjuster <NUM> may be interchanged. In other words, the wavelength level adjuster <NUM> and the first power amplifier <NUM> are sequentially connected. This is not limited in this application.

In this embodiment, the first power amplifier <NUM> may include a pump source and a doped fiber. The pump source is disposed upstream or downstream of the doped fiber along a transmission direction of an optical signal, and there may be one or more pump sources.

In this embodiment, that the wavelength level adjuster <NUM> performs power adjustment on each wavelength based on the adjustment control signal means that the wavelength level adjuster performs power adjustment on each wavelength by generating different insertion loss for each wavelength. In other words, power of an optical signal carrying different wavelengths is amplified a corresponding number of times based on a gain characteristic parameter of the first power amplifier. The wavelength level adjuster generates different insertion loss values for the optical signal with different wavelengths, and the insertion loss values are applied to optical power of each wavelength output by the first power amplifier. In this way, power adjustment is implemented on each wavelength.

In this embodiment, the controller may obtain the first amplification control signal and the adjustment control signal through calculation based on the gain characteristic parameter of the first power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, information about target output optical power of the fiber amplifier, and the input optical signal of the fiber amplifier. The gain characteristic parameter of the first power amplifier may be a power amplification factor of each wavelength by the first power amplifier. The adjustment control characteristic parameter of the wavelength level adjuster may be a relationship parameter between an insertion loss of each wavelength and the adjustment control signal.

It may be understood that the fiber amplifier disclosed in this embodiment may obtain the first amplification control signal and the adjustment control signal through calculation based on the input optical signal received by the first input end. The first amplification control signal may control the first power amplifier to perform power amplification on each wavelength, the adjustment control signal may control the wavelength level adjuster to perform insertion loss adjustment on each wavelength, and an effect of insertion loss adjustment is applied to optical power of each wavelength of the fiber amplifier. In this way, single-wavelength gain adjustment is implemented on a gain curve of the fiber amplifier, and adjustment precision of the gain curve of the fiber amplifier is improved.

Therefore, the gain curve of the fiber amplifier disclosed in this embodiment may be adjusted to be relatively flat, thereby improving system flatness, releasing a flatness margin designed in a system specification, and reducing a power equalizer (dynamic gain equalizer, DGE) site.

Currently, a fiber amplifier equipped with a built-in GFF is used as a solution to adjust the gain curve of the fiber amplifier. The GFF has a relatively narrow insertion loss adjustment range, and usually needs to perform insertion loss adjustment in cooperation with a variable optical attenuator (variable optical attenuator, VOA) to meet a requirement of the target output optical power. However, the wavelength level adjuster of the fiber amplifier disclosed in this embodiment of this application has a relatively wide insertion loss adjustment range, and can independently perform insertion loss adjustment on the optical power of each wavelength without cooperation with the original VOA.

In addition, the fiber amplifier disclosed in this embodiment can implement single-wavelength gain adjustment, so that insertion loss values of some wavelengths can be correspondingly controlled when a wavelength is dropped or added in a live network. This effectively suppresses power jitter.

In an optional implementation, the controller <NUM> includes a first storage module <NUM> and a first calculation module <NUM>. The first storage module <NUM> is configured to store the gain characteristic parameter of the first power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, and the information about the target output optical power of the fiber amplifier. The first calculation module <NUM> is configured to obtain the first amplification control signal and the adjustment control signal through calculation based on the content stored by the storage module and the input optical signal of the fiber amplifier.

<FIG> is a schematic structural diagram of a controller according to an embodiment of this application. The gain characteristic parameter of the first power amplifier may be a power amplification factor of each wavelength by the first power amplifier. The adjustment control characteristic parameter of the wavelength level adjuster may be a relationship parameter between an insertion loss of each wavelength and the adjustment control signal. For example, for a wavelength level adjuster including an LCOS chip, an adjustment control characteristic parameter of the wavelength level adjuster including the LCOS chip may be a relationship parameter between an output deflection angle of a signal of each wavelength and a drive voltage.

In an optional implementation, <FIG> is a schematic structural diagram of a wavelength level adjuster according to an embodiment of this application. The wavelength level adjuster <NUM> includes a dispersion module <NUM>, a wavelength level insertion loss adjustment module <NUM>, and an aggregation module <NUM>. The dispersion module <NUM>, the wavelength level insertion loss adjustment module <NUM>, and the aggregation module <NUM> are sequentially connected. The dispersion module <NUM> is configured to perform spatial separation on a multi-wavelength optical signal. The aggregation module <NUM> is configured to perform spatial aggregation on the multi-wavelength optical signal. The wavelength level insertion loss adjustment module <NUM> is configured to perform power adjustment on each wavelength based on the adjustment control signal.

The dispersion module <NUM> may include an optical element having a dispersion characteristic, such as a grating and a prism, to perform spatial separation on the multi-wavelength optical signal, in other words, to spatially separate an optical signal with different wavelengths. This better facilitates single-wavelength power adjustment performed by the wavelength level insertion loss adjustment module. The aggregation module <NUM> may include a dispersion element disposed in a reverse direction, to perform spatial aggregation on the multi-wavelength optical signal, in other words, to spatially aggregate an optical signal with different wavelengths. The wavelength level insertion loss adjustment module <NUM> may include an LCOS chip, a MEMS element, an LC element, or the like that may control, by using a control signal, an optical power loss of each wavelength of the LCOS chip, the MEMS element, the LC element, or the like. For example, for the LCOS chip, when different drive voltages are loaded on the LCOS chip, the different wavelengths can be controlled to perform corresponding angle rotation, and an output direction of the optical signal deviates from a direction of a receive port by a specific angle. In this way, different insertion loss adjustment is implemented for different wavelengths.

In an optional implementation, <FIG> is a schematic structural diagram of another wavelength level adjuster according to an embodiment of this application. Compared with the wavelength level adjuster <NUM> shown in <FIG>, a wavelength level adjuster <NUM>' in <FIG> further includes a first beam shaping module <NUM>' and a second beam shaping module <NUM>'. The first beam shaping module <NUM>', a dispersion module <NUM>', a wavelength level insertion loss adjustment module <NUM>', an aggregation module <NUM>', and the second beam shaping module <NUM>' are sequentially connected. The first beam shaping module <NUM>' and the second beam shaping module <NUM>' are configured to perform beam focusing and beam collimation, and may include elements having a beam focusing function and a beam collimation function, such as a lens and a prism.

Another embodiment of this application discloses another fiber amplifier. Compared with the fiber amplifier shown in <FIG>, the controller <NUM> not only includes the first input end I1 and the control output end O, but also includes a second input end I2. The first input end I1 is configured to receive the input optical signal of the fiber amplifier, and the second input end I2 is configured to receive an output optical signal of the fiber amplifier.

The controller <NUM> obtains the first amplification control signal and the adjustment control signal through calculation based on the input optical signal.

The controller <NUM> obtains a second amplification control signal and a secondary adjustment control signal through calculation based on the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold.

The control output end O is configured to output the first amplification control signal or the second amplification control signal to the first power amplifier <NUM>, and output the adjustment control signal or the secondary adjustment control signal to the wavelength level adjuster <NUM>.

The wavelength level adjuster <NUM> is configured to perform power adjustment on each wavelength based on the adjustment control signal or the secondary adjustment control signal.

In this embodiment, positions of the first power amplifier and the wavelength level adjuster may be interchanged.

In this embodiment, the controller reads the input optical signal, analyzes optical power of each wavelength of the input optical signal, and obtains the first amplification control signal and the adjustment control signal through calculation based on the gain characteristic parameter of the first power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, and the information about the target output optical power of the fiber amplifier that are stored in the controller. The first power amplifier performs power amplification on each wavelength based on the first amplification control signal, and the wavelength level adjuster performs power adjustment on each wavelength based on the adjustment control signal.

To accurately adjust the gain curve of the fiber amplifier, the first power amplifier and the wavelength level adjuster may perform adjustment for a plurality of times. Specifically, when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold, the controller <NUM> reads the output optical signal of the fiber amplifier, analyzes optical power of each wavelength of the output optical signal, and obtain the second amplification control signal and the secondary adjustment control signal through calculation based on the gain characteristic parameter of the first power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, and the information about the target output optical power of the fiber amplifier. The first power amplifier <NUM> performs power amplification on each wavelength again based on the second amplification control signal, and the wavelength level adjuster <NUM> performs power adjustment on each wavelength again based on the secondary adjustment control signal.

Compared with the fiber amplifier shown in <FIG>, the second input end I2 is added to the controller of the fiber amplifier disclosed in this embodiment. The controller may obtain the second amplification control signal and the secondary adjustment control signal through calculation based on the optical power of each wavelength of the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold. The secondary adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength again, until an absolute value of a difference between power of the output optical signal and the target output optical power is less than the secondary calculation threshold, so that the power of the output optical signal is closer to the target output optical power. This improves adjustment accuracy of the gain curve of the fiber amplifier.

In an optional implementation, the controller may further include a first storage module and a first calculation module. The first storage module has the same function and stores the same content as the first storage module <NUM> shown in <FIG>. In addition to completing work to be completed by the first calculation module <NUM> shown in <FIG>, the first calculation module is further configured to obtain the second amplification control signal and the secondary adjustment control signal through calculation based on the content stored by the storage module and the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold.

The wavelength level adjuster in this embodiment is the same as the wavelength level adjuster <NUM> or <NUM>' in the previous embodiment.

<FIG> is a schematic structural diagram of a fiber amplifier according to another embodiment of this application. It can be learned from <FIG> that the fiber amplifier <NUM> includes a first power amplifier <NUM>, a second power amplifier <NUM>, a wavelength level adjuster <NUM>, and a controller <NUM>. The first power amplifier <NUM>, the wavelength level adjuster <NUM>, and the second power amplifier <NUM> are sequentially connected. The controller <NUM> includes a first input end I1 and a control output end O. The first input end I1 is configured to receive an input optical signal of the fiber amplifier. The control output end O is configured to output a first amplification control signal to the first power amplifier <NUM>, and output a second amplification control signal to the second power amplifier <NUM>, and output an adjustment control signal to the wavelength level adjuster <NUM>. The wavelength level adjuster <NUM> is configured to perform power adjustment on each wavelength based on the adjustment control signal.

In this embodiment, the first power amplifier <NUM> and the second power amplifier <NUM> are respectively used as a preamplifier and a power amplifier of the fiber amplifier, and may include a pump source and a doped fiber. The pump source is disposed upstream or downstream of the doped fiber along a transmission direction of an optical signal, and there may be one or more pump sources.

Compared with the fiber amplifier shown in <FIG>, the second power amplifier <NUM> is added to the fiber amplifier disclosed in this embodiment. The controller <NUM> may obtain the first amplification control signal, the second amplification control signal, and the adjustment control signal through calculation based on gain characteristic parameters of the first power amplifier <NUM> and the second power amplifier <NUM>, an adjustment control characteristic parameter of the wavelength level adjuster <NUM>, information about target output optical power of the fiber amplifier, and the input optical signal of the fiber amplifier. The first power amplifier <NUM> and the second power amplifier <NUM> perform power amplification on each wavelength respectively based on the first amplification control signal and the second amplification control signal. The wavelength level adjuster <NUM> performs power adjustment on each wavelength based on the adjustment control signal. Therefore, the first power amplifier <NUM>, the wavelength level adjuster <NUM>, and the second power amplifier <NUM> cooperate with each other to implement wavelength level adjustment on a gain curve of the fiber amplifier.

In an optional implementation, the controller <NUM> includes a second storage module <NUM> and a second calculation module <NUM>. In addition to storing the content stored by the first storage module <NUM> shown in <FIG>, the second storage module <NUM> further stores the gain characteristic parameter of the second power amplifier. The second calculation module <NUM> is configured to obtain the first amplification control signal and the adjustment control signal through calculation based on the content stored by the second storage module <NUM> and optical power of each wavelength of the input optical signal of the fiber amplifier.

In an optional implementation, as shown in <FIG>, a controller <NUM>' further includes a second input end I2, where the second input end I2 is configured to receive an output optical signal of a fiber amplifier. A second calculation module <NUM>' is further configured to obtain a third amplification control signal, a fourth amplification control signal, and a secondary adjustment control signal through calculation based on the content stored by the storage module and optical power of each wavelength of the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold. The control output end O is further configured to output the third amplification control signal to a first power amplifier <NUM>', output the fourth amplification control signal to a second power amplifier <NUM>', and output the secondary adjustment control signal to a wavelength level adjuster <NUM>'. The wavelength level adjuster <NUM>' is further configured to perform power adjustment on each wavelength based on the secondary adjustment control signal.

Compared with the fiber amplifier shown in <FIG>, the second input end I2 is added to the controller of the fiber amplifier disclosed in this implementation. The controller may obtain the third amplification control signal, the fourth amplification control signal, and the secondary adjustment control signal through calculation based on the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold. The secondary adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength again, until an absolute value of a difference between power of the output optical signal and the target output optical power is less than the secondary calculation threshold, so that the power of the output optical signal is closer to the target output optical power. This improves adjustment accuracy of the gain curve of the fiber amplifier.

<FIG> shows a gain adjustment method for a fiber amplifier according to an embodiment of this application. The method is applied to the fiber amplifier shown in <FIG>, and the method includes the following steps:.

In this embodiment, the obtaining a first amplification control signal and an adjustment control signal through calculation based on optical power of each wavelength of the input optical signal of the fiber amplifier may be obtaining the first amplification control signal and the adjustment control signal through calculation based on a gain characteristic parameter of the first power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, information about target output optical power of the fiber amplifier, and the input optical signal of the fiber amplifier. The gain characteristic parameter of the first power amplifier may be a power amplification factor of each wavelength by the first power amplifier. The adjustment control characteristic parameter of the wavelength level adjuster may be a relationship parameter between an insertion loss of each wavelength and the adjustment control signal.

In this embodiment, the first amplification control signal is used to control the first power amplifier to perform power amplification on an optical signal with different wavelengths. The adjustment control signal is used to control the wavelength level adjuster to implement different insertion losses for optical power of the different wavelengths.

It may be understood that, according to the gain adjustment method disclosed in this embodiment, the first amplification control signal and the adjustment control signal may be obtained through calculation based on the optical power of each wavelength of the input optical signal received by a first input end. The first amplification control signal may control the first power amplifier to perform power amplification on each wavelength, the adjustment control signal may control the wavelength level adjuster to perform insertion loss adjustment on each wavelength, and an effect of insertion loss adjustment is applied to optical power of each wavelength of the fiber amplifier. In this way, single-wavelength gain adjustment is implemented on a gain curve of the fiber amplifier, and adjustment precision of the gain curve of the fiber amplifier is improved.

In an optional implementation, the obtaining a first amplification control signal and an adjustment control signal through calculation based on optical power of each wavelength of the input optical signal of the fiber amplifier includes: obtaining the first amplification control signal and the adjustment control signal through calculation based on a gain characteristic parameter of the first power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, target output optical power of the fiber amplifier, and the input optical signal of the fiber amplifier.

Specific explanations of the gain characteristic parameter of the first power amplifier and the adjustment control characteristic parameter of the wavelength level adjuster are the same as explanations of the gain characteristic parameter of the first power amplifier and the adjustment control characteristic parameter of the wavelength level adjuster in the fiber amplifier shown in <FIG>.

In an optional implementation, after that outputting the first amplification control signal to a first power amplifier, and outputting the adjustment control signal to the wavelength level adjuster, the method further includes: receiving an output optical signal of the fiber amplifier; obtaining a second amplification control signal and a secondary adjustment control signal through calculation based on the gain characteristic parameter of the first power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, the target output optical power of the fiber amplifier, and optical power of each wavelength of the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold; and outputting the second amplification control signal to the first power amplifier, and outputting the secondary adjustment control signal to the wavelength level adjuster.

A specific flowchart of this implementation is shown in <FIG>.

First, read the input optical signal of the fiber amplifier (step <NUM>), and analyze the optical power of each wavelength of the input optical signal.

Then, read the gain characteristic parameter of the first power amplifier, an adjustment parameter of the wavelength level adjuster, and the information about the target output optical power (step <NUM>).

Calculate the first amplification control signal (step <NUM>) and the adjustment control signal (step <NUM>) based on the read content, output the first amplification control signal to the first power amplifier (step <NUM>), and output the adjustment control signal to the wavelength level adjuster (step <NUM>).

Obtain the output optical signal of the fiber amplifier (step <NUM>), and analyze the optical power of each wavelength of the output optical signal.

To accurately adjust the gain curve of the fiber amplifier, the first power amplifier and the wavelength level adjuster may perform adjustment for a plurality of times. Therefore, the controller reads the output optical signal of the fiber amplifier (step <NUM>) when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold (step <NUM>).

In addition, obtain the second amplification control signal (step <NUM>) and the secondary adjustment control signal (step <NUM>) through calculation based on the gain characteristic parameter of the first power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, and the information about the target output optical power of the fiber amplifier.

The second amplification control signal controls the first power amplifier to perform power amplification on each wavelength again. The secondary adjustment control signal controls the wavelength level adjuster to perform power adjustment on each wavelength again.

It may be understood that the second amplification control signal and the secondary adjustment control signal are obtained through calculation based on the optical power of each wavelength of the output optical signal when the absolute value of the difference between the power of the output optical signal and the target output optical power is greater than the secondary calculation threshold. The secondary adjustment control signal may control the wavelength level adjuster to perform power adjustment on each wavelength again, until an absolute value of a difference between power of the output optical signal and the target output optical power is less than the secondary calculation threshold, so that the power of the output optical signal is closer to the target output optical power. This improves adjustment accuracy of the gain curve of the fiber amplifier.

<FIG> shows a gain adjustment method for another fiber amplifier according to an embodiment of this application. The method is applied to the fiber amplifier shown in <FIG>, and the method includes the following steps:.

A specific implementation method for this implementation is the same as the adjustment implementation method for the fiber amplifier shown in <FIG>. The first amplification control signal, the second amplification control signal, and the adjustment control signal are obtained through calculation based on gain characteristic parameters of the first power amplifier and the second power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, information about target output optical power of the fiber amplifier, and the input optical signal of the fiber amplifier.

The first amplification control signal, the second amplification control signal, and the adjustment control signal cooperate with each other. The first amplification control signal and the second amplification control signal respectively control the first power amplifier and the second power amplifier to perform power amplification on each wavelength. The adjustment control signal controls the wavelength level adjuster to perform power adjustment on each wavelength.

In an optional implementation, the obtaining a first amplification control signal and an adjustment control signal through calculation based on optical power of each wavelength of the input optical signal of the fiber amplifier, and the obtaining a second amplification control signal through calculation based on the optical power of each wavelength of the input optical signal of the fiber amplifier include: obtaining the first amplification control signal, the second amplification control signal, and the adjustment control signal through calculation based on gain characteristic parameters of the first power amplifier and the second power amplifier, an adjustment control characteristic parameter of the wavelength level adjuster, target output optical power of the fiber amplifier, and the optical power of each wavelength of the input optical signal of the fiber amplifier.

Specific explanations of the gain characteristic parameters of the first power amplifier and the second power amplifier and the adjustment control characteristic parameter of the wavelength level adjuster are the same as explanations of the gain characteristic parameters of the first power amplifier and the second power amplifier and the adjustment control characteristic parameter of the wavelength level adjuster in the fiber amplifier shown in <FIG>.

In an optional implementation, after the outputting the first amplification control signal to a first power amplifier, outputting the adjustment control signal to the wavelength level adjuster, and outputting the second amplification control signal to a second power amplifier, the method further includes: receiving an output optical signal of the fiber amplifier; obtaining a third amplification control signal, a fourth amplification control signal, and a secondary adjustment control signal through calculation based on the gain characteristic parameters of the first power amplifier and the second power amplifier, the adjustment control characteristic parameter of the wavelength level adjuster, the target output optical power of the fiber amplifier, and optical power of each wavelength of the output optical signal when an absolute value of a difference between power of the output optical signal and the target output optical power is greater than a secondary calculation threshold; and outputting the third amplification control signal to the first power amplifier, outputting the fourth amplification control signal to the second power amplifier, and outputting the secondary adjustment control signal to the wavelength level adjuster.

A specific implementation method for this implementation is the same as that of the fiber amplifier shown in <FIG>.

The foregoing embodiments may be implemented by using a combination of software, hardware, firmware, and the like. When the controller in the foregoing embodiments is implemented by using software, all or a part of the controller may be implemented in a form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the procedure or functions according to the embodiments of this application are all or partially generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable apparatuses. The computer instruction may be stored in a computer readable storage medium, or may be transmitted by using the computer readable storage medium. The computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired (for example, a coaxial cable, an optical fiber, or a digital subscriber line (digital subscriber line, DSL)) or wireless (for example, infrared, radio, or microwave) manner. The computer-readable storage medium may be any usable medium accessible by a computer, or a data storage device, such as a server or a data center, integrating one or more usable media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, a digital versatile disc (digital versatile disc, DVD), a semiconductor medium (for example, a solid-state drive (solid-state disk, SSD)), or the like.

Claim 1:
A fiber amplifier (<NUM>, <NUM>, <NUM>'), comprising a first power amplifier (<NUM>, <NUM>, <NUM>'), a wavelength level adjuster (<NUM>, <NUM>, <NUM>'), and a controller (<NUM>, <NUM>, <NUM>'), wherein the first power amplifier (<NUM>, <NUM>, <NUM>') is connected to the wavelength level adjuster (<NUM>, <NUM>, <NUM>');
the controller (<NUM>, <NUM>, <NUM>') comprises a first input end and a control output end, wherein the first input end is configured to receive an input optical signal of the fiber amplifier, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster; and
the wavelength level adjuster (<NUM>, <NUM>, <NUM>') is configured to perform in a dispersion module of the wavelength level adjuster spatial separation on a received optical signal, to obtain multiple single-wavelength signals;
perform power adjustment on each the single-wavelength signal based on the adjustment control signal, to obtain multiple separated optical signals after power adjustment, and
perform in an aggregation module of the wavelength level adjuster spatial aggregation on the multiple separated optical signals after power adjustment.