Optical amplifier and optical communication system

Abstract

The present application discloses an optical amplifier and an optical communication system, which releases or consumes the pump energy required by each level of optical amplification structure in real time and dynamically by adaptively adjusting the energy of complementary light corresponding to the signal light, thereby eliminating the transient overshoot phenomenon. The aforementioned optical amplifier may include an optical amplifier controller, a combiner, a first device, and an N-level optical amplifier structure arranged in a cascade manner. Among them, the N-level optical amplifier structure is used to amplify the signal light; the optical amplifier controller is used to obtain a first gain value of the signal light, and determine a first VOA value and a first pump current value corresponding to the first gain value according to the first gain value and the correlation relationship, and send the first VOA value corresponding to the first gain value to the first device. The first device is used to adjust the loop attenuation according to the first VOA value to emit complementary light corresponding to the signal light.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical transmission technology, and specifically to an optical amplifier and an optical communication system. Background Art

[0002] With the deployment of automatically switched optical networks (ASON) and reconfigurable optical add / drop multiplexer (ROADM) sites, there are more and more scenarios of dynamically adding and dropping channels in optical communication wavelength division networks. When adding or dropping channels, the optical power of the signal light at the input of the optical amplifier will change dramatically. When adding channels, the optical power entering the optical amplifier increases, resulting in a decrease in the contribution of the pump light to each signal channel, a sudden drop in the single-wavelength optical power, and a transient undershoot. When dropping channels, the optical power entering the optical amplifier suddenly decreases, resulting in an increase in the contribution of the excess pump light to the remaining signal channels, an increase in the single-wavelength optical power, and a transient overshoot. Taking the erbium-doped fiber amplifier (EDFA) in the existing network as an example, in order to pursue adjustable gain and better noise performance, the following are usually adopted: Figure 1 In the multi-stage amplification structure shown in the figure, the erbium fiber of the first-stage optical amplification structure is in a saturated state, resulting in an enhanced gain competition relationship between channels. The cascading of optical amplifiers in the communication network link, the increase in the number of wave additions and drops, the faster switching speed, and even fiber breakage will further increase the transient overshoot (including transient overshoot and transient undershoot) effect of the optical amplifier in the process of wave addition and drop, resulting in transient interruption of services and affecting the normal operation of the system.

[0003] At present, in order to reduce the transient overshoot effect of the optical amplifier during the wave addition and drop process, the open-loop response time of the optical amplifier is usually reduced through an electric control circuit to change the pump power of each level of the optical amplifier structure, so that the change of the pump power can keep up with the change of the optical power at the input end of the optical amplifier as much as possible, so as to reduce the signal overshoot. Specifically, the change of the optical power at the input end of the optical amplifier is detected by the input end detector, and then the configuration table is queried by the optical amplifier controller according to the current optical amplifier input power, and the pump power of each level of the optical amplifier structure is controlled by the corresponding pump current. However, the time of the electric control open-loop response cannot be reduced indefinitely, and the electric control response always lags behind the change of the optical power at the input end of the optical amplifier. Therefore, the current method can only suppress the transient overshoot of part of the optical amplifier, but cannot completely eliminate the transient overshoot phenomenon of the optical amplifier; and as the number of cascaded optical amplifiers increases, this transient overshoot effect will be continuously expanded, thereby affecting the network performance. Summary of the invention

[0004] The embodiments of the present application provide an optical amplifier and an optical communication system, which release or consume the pump energy required by each level of optical amplification structure in real time and dynamically by adaptively adjusting the energy of complementary light corresponding to the signal light, thereby eliminating transient overshoot.

[0005] In a first aspect, an embodiment of the present application provides an optical amplifier. The optical amplifier includes an optical amplifier controller, a combiner, a first device, and an N-stage optical amplifier structure arranged in a cascade manner. The optical amplifier controller is connected to the first device and to each stage of the optical amplifier structure in the N-stage optical amplifier structure. The combiner is connected to the input end of the first-stage optical amplifier structure, or is connected between the output end of the K-stage optical amplifier structure and the input end of the K+1-stage optical amplifier structure. Moreover, the first end of the first device is connected to the combiner, and the second end of the first device is connected to the output end of the N-stage optical amplifier structure or is connected between the output end of the M-stage optical amplifier structure and the input end of the M+1-stage optical amplifier structure, N≥2, 1≤K≤M, 2≤M≤N, and N, M, and K are integers. The N-stage optical amplifier structure is used to amplify the signal light. The optical amplifier controller is used to obtain a first gain value of the signal light, and determine a first VOA value and a first pump current value corresponding to the first gain value according to the association relationship. The described association relationship is the relationship between the first gain value, the first VOA value and the first pump current value, the first VOA value reflects the loop attenuation of the first device, and the first pump current value reflects the pump current required by each level of the optical amplification structure in the N-level optical amplification structure. Then, the optical amplifier controller sends the first VOA value to the first device. The first device is used to adjust the loop attenuation according to the first VOA value to emit complementary light corresponding to the signal light.

[0006] Through the above method, before the addition and dropout wave occurs, the first device in the optical control loop can first adjust the loop attenuation size according to the first VOA value corresponding to the first gain value, so as to ensure that the complementary light corresponding to the signal light can maintain normal operation. In this way, when the addition and dropout wave occurs, due to the fast response speed of the optical control loop, in the process of the optical amplifier controller adjusting the pump power in each level of optical amplifier structure according to the first pump current value, the complementary light can release or consume the pump energy of each level of optical amplifier structure enabled by the first pump current value according to the optical amplifier input power of the signal light, thereby eliminating the phenomenon of optical amplifier transient overshoot generated by the signal light in each level of optical amplifier structure.

[0007] In some optional examples, the optical amplifier controller is further used to obtain a second gain value of the signal light, and a second VOA value and a second pump current value corresponding to the second gain value. Furthermore, when the first gain value is not equal to the second gain value, the optical amplifier controller updates the first gain value to the second gain value, updates the first VOA value to the second VOA value, and updates the first pump current value to the second pump current value.

[0008] Through the above method, the optical amplifier controller can also update the first gain value to the second gain value when the first gain value is not equal to the second gain value, and update the first VOA value to the second VOA value and the first pump current value to the second pump current value, so as to dynamically adjust the gain of the signal light to meet the requirements of different users for the gain of the signal light.

[0009] In some optional examples, the optical amplifier controller is also used to obtain the optical amplifier input power of the signal light at the current moment and the optical amplifier input power at the previous moment, and determine the change of the optical amplifier input power according to the optical amplifier input power at the current moment and the optical amplifier input power at the previous moment. Then, when the change of the optical amplifier input power is greater than the open-loop threshold, the optical amplifier controller also controls the pump power of each level of the optical amplifier structure according to the second pump current value, and sends the second VOA value to the first device. In this way, the first device is also used to adjust the loop attenuation according to the second VOA value. In the above manner, it is possible to achieve that on the basis of eliminating the phenomenon of transient overshoot of the optical amplifier, by performing an open-loop adjustment operation, the optical amplifier structure at each level can still provide stable gain for the signal light.

[0010] In some optional examples, the optical amplifier controller is also used to obtain the optical amplifier output power of the signal light at the current moment, and calculate the actual gain value of the signal light based on the optical amplifier input power at the current moment and the optical amplifier output power at the current moment. Then, the optical amplifier controller calculates the gain difference value between the actual gain value and the second gain value. And, when the gain difference value is greater than or equal to the closed-loop threshold, the optical amplifier controller adjusts the third pump current value corresponding to the actual gain value according to the gain difference value, so as to control the pump power of each level of optical amplifier structure, and adjusts the third VOA value corresponding to the actual gain value according to the gain difference value. Wherein, the closed-loop threshold is less than the open-loop threshold. The first device is also used to: adjust the loop attenuation size according to the third VOA value. In the above manner, if the gain difference value is greater than or equal to the closed-loop threshold, the optical amplifier controller fine-tunes the third pump current value and the third VOA value so that the adjusted third pump current value can approach the second pump current value, and the adjusted third VOA value can also approach the second VOA value, ensuring that the gain of the signal light can be accurately controlled and kept stable at this time.

[0011] In some optional examples, the optical amplifier also includes a second device. The first end of the second device is connected to the output end of the M-th optical amplification structure, the first end of the second device is connected to the input end of the M+1-th optical amplification structure, and the third end of the second device is connected to the first device. Alternatively, the first end of the second device is connected to the output end of the N-th optical amplification structure. The second device is used to determine the wavelength band of the complementary light, or to determine the split power of the complementary light. In the above manner, the second device can be used as a component of the aforementioned optical control circuit to determine the wavelength band of the complementary light, or to determine the split power of the complementary light, so as to provide a candidate range of the lasing wavelength or the lasing power in the process of lasing complementary light.

[0012] In some optional examples, the second device includes a first wave splitter. The first wave splitter is used to separate the wavelength band of the signal light and the wavelength band of the complementary light to determine the wavelength band of the complementary light. Alternatively, the first wave splitter is used to generate a filter spectrum line and obtain a spontaneous emission ASE spectrum line modulated by the N-stage optical amplification structure, and determine the wavelength of the complementary light based on the filter spectrum line and the spontaneous emission ASE spectrum line.

[0013] In some optional examples, the second device includes a coupler, and the coupler is used to determine the splitting power of the signal light and the complementary light.

[0014] In some optional examples, the first device includes a first adjustable optical attenuator and a first filter, wherein the first filter is used to select a lasing wavelength from the wavelength band of the complementary light, so as to lasing the complementary light at the lasing wavelength after the first adjustable optical attenuator adjusts the loop attenuation.

[0015] In some optional examples, the first device includes a second adjustable optical attenuator. The second adjustable optical attenuator is used to laser the complementary light according to the wavelength of the complementary light after adjusting the loop attenuation. In the above manner, the second device in the optical amplifier does not include the first filter, and can also directly determine the wavelength of the complementary light through the second splitter, without the need to select a suitable laser wavelength from the wavelength band of the complementary light through the filter again, saving cost and volume.

[0016] In some optional examples, the first device includes a third adjustable optical attenuator and a second filter, wherein the second filter is used to determine the optical power of the complementary light from the split optical power of the signal light and the complementary light, so as to laser the complementary light according to the optical power of the complementary light after the third adjustable optical attenuator adjusts the loop attenuation.

[0017] In some optional examples, the optical amplifier further includes a third filter and an optical amplifier output end. The first end of the third filter is connected to the optical amplifier output end, and the second end of the third filter is connected to the optical amplifier controller. The third filter is used to filter the complementary light before the optical amplifier controller obtains the optical amplifier output power of the signal light at the current moment.

[0018] In some optional examples, the optical amplifier further includes an input end detector. A first end of the input end detector is connected to an input end of the first-stage optical amplifier structure, and a second end of the input end detector is connected to the optical amplifier controller. The input end detector is used to detect the optical amplifier input power of the signal light at a current moment, and send the optical amplifier input power at a current moment to the optical amplifier controller.

[0019] In some optional examples, the optical amplifier further includes an output end detector. A first end of the output end detector is connected to the output end of the Nth optical amplifier structure or the second device, and a second end of the output end detector is connected to the optical amplifier controller. The output end detector is used to detect the optical amplifier output power of the signal light at the current moment, and send the optical amplifier output power at the current moment to the optical amplifier controller.

[0020] In some optional examples, the optical amplifier further includes an optical amplifier input end, and the optical amplifier input end is connected to the input end of the first-stage optical amplifier structure.

[0021] In a second aspect, an embodiment of the present application provides an optical communication system, which may include an optical transmitter and at least one optical amplifier as in the first aspect or any possible optical amplifier in the first aspect. The optical transmitter is used to generate signal light.

[0022] In some optional examples, the optical communication system may further include a first optical multiplexer / demultiplexer, a second optical multiplexer / demultiplexer, an optical fiber link, and an optical receiver.

[0023] In some optional examples, the optical communication system may further include a filtering device.

[0024] In the third aspect, an embodiment of the present application provides a method for processing transient overshoot. The method for processing transient overshoot can be applied to an optical amplifier. In the processing method, the optical amplifier obtains a first gain value of the signal light, and determines a first VOA value and a first pump current value corresponding to the first gain value based on a correlation relationship. Among them, the correlation relationship is the relationship between the first gain value, the first VOA value, and the first pump current value, the first VOA value reflects the loop attenuation of the first device in the optical amplifier, and the first pump current value reflects the pump current required for each level of the optical amplification structure in the N-level optical amplification structure in the optical amplifier. Then, the optical amplifier adjusts the loop attenuation according to the first VOA value to emit complementary light corresponding to the signal light.

[0025] In some optional examples, the processing method further includes: obtaining a second gain value of the signal light, and a second VOA value and a second pump current value corresponding to the second gain value. Furthermore, when the first gain value is not equal to the second gain value, the optical amplifier updates the first gain value to the second gain value, updates the first VOA value to the second VOA value, and updates the first pump current value to the second pump current value.

[0026] In some optional examples, the processing method further includes: the optical amplifier obtains the optical amplifier input power of the signal light at the current moment and the optical amplifier input power at the previous moment, and determines the optical amplifier input power change according to the optical amplifier input power at the current moment and the optical amplifier input power at the previous moment. Then, when the optical amplifier input power change is greater than the open-loop threshold, the optical amplifier controls the pump power of each level of the optical amplifier structure according to the second pump current value, and adjusts the loop attenuation according to the second VOA value.

[0027] In some optional examples, the processing method further includes: the optical amplifier obtains the optical amplifier output power of the signal light at the current moment, and calculates the actual gain value of the signal light based on the optical amplifier input power at the current moment and the optical amplifier output power at the current moment. Then, the optical amplifier calculates the gain difference value between the actual gain value and the second gain value. Moreover, when the gain difference value is greater than or equal to the closed-loop threshold, the optical amplifier adjusts the third pump current value corresponding to the actual gain value according to the gain difference value to control the pump power of each level of the optical amplifier structure, and adjusts the third VOA value corresponding to the actual gain value according to the gain difference value. Among them, the closed-loop threshold is less than the open-loop threshold. The optical amplifier also adjusts the loop attenuation size according to the third VOA value.

[0028] In some optional examples, the processing method further includes: an optical amplifier determining a wavelength band of the complementary light or determining a split light power of the complementary light.

[0029] In some optional examples, the processing method further includes: an optical amplifier separating the wavelength band of the signal light and the wavelength band of the complementary light to determine the wavelength band of the complementary light. Furthermore, the optical amplifier selects a lasing wavelength from the wavelength band of the complementary light to laser the complementary light at the lasing wavelength after adjusting the loop attenuation.

[0030] In some optional examples, the processing method further includes: the optical amplifier generates a filter spectrum line and obtains a spontaneous emission ASE spectrum line modulated by an N-stage optical amplification structure, and determines the wavelength of the complementary light based on the filter spectrum line and the spontaneous emission ASE spectrum line. After adjusting the loop attenuation, the optical amplifier lases the complementary light according to the wavelength of the complementary light.

[0031] In some optional examples, the processing method further includes: an optical amplifier determines the splitting power of the signal light and the complementary light. Furthermore, the optical amplifier determines the optical power of the complementary light from the splitting power of the signal light and the complementary light, so as to laser the complementary light according to the optical power of the complementary light after adjusting the loop attenuation.

[0032] In some optional examples, the processing method further includes: the optical amplifier filters the complementary light before the optical amplifier controller obtains the optical amplifier output power of the signal light at the current moment.

[0033] In some optional examples, the processing method further includes: the optical amplifier detects the optical amplifier input power of the signal light at a current moment.

[0034] In some optional examples, the processing method further includes: the optical amplifier detects the optical amplifier output power of the signal light at a current moment.

[0035] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0036] In the embodiment of the present application, the optical amplifier controller controls the pump power of each level of optical amplifier structure according to the first pump current value, and the first VOA value is fed back to the first device. In this way, in the process of the optical amplifier controller adjusting the pump power of each level of optical amplifier structure according to the first pump current value, the first device can first adjust the loop attenuation according to the first VOA value, thereby adjusting the energy of the complementary light, and then the complementary light can release or consume the pump energy of each level of optical amplifier structure enabled by the first pump current value, so as to eliminate the phenomenon of transient overshoot of the optical amplifier generated by the signal light in each level of optical amplifier structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application.

[0038] Figure 1 A schematic diagram of a multi-stage amplification structure in the related art;

[0039] Figure 2a A structural schematic diagram of an optical amplifier is provided for an embodiment of the present application;

[0040] Figure 2b-2d Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0041] Figure 3 Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0042] Figure 4a A schematic diagram of open-loop regulation provided in an embodiment of the present application;

[0043] Figure 4b A schematic diagram of closed-loop regulation provided in an embodiment of the present application;

[0044] Figure 5a-Figure 5b Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0045] Figure 6a-6b Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0046] Figure 7 A schematic diagram of an equivalent filter band provided in an embodiment of the present application;

[0047] Figure 8a-8d Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0048] Fig. 9 Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0049] Fig.10 Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0050] Fig.11 Another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application;

[0051] Fig.12a Schematic diagram of the spectrum of the intermediate-level optical amplification structure;

[0052] Figure 12b is a schematic diagram of the spectrum of the output end of the optical amplifier;

[0053] Fig.13a A schematic diagram of transient overshoot generated by the existing solution during the process of adding and dropping waves;

[0054] Fig.13b A schematic diagram of transient overshoot generated during the wave addition and dropout process provided in this embodiment;

[0055] Fig.14a A schematic diagram of the structure of the optical communication system provided in this embodiment;

[0056] Fig.14b Another schematic diagram of the structure of the optical communication system provided in this embodiment;

[0057] Fig.15 A schematic flow chart of a method for processing transient overshoot provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The embodiments of the present application provide an optical amplifier and an optical communication system, which are used to release or consume the pump energy required by each level of optical amplification structure in real time and dynamically by adaptively adjusting the energy of complementary light corresponding to the signal light, thereby eliminating transient overshoot.

[0059] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0060] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the implementation of the application described here can be implemented in an order other than those illustrated or described here. In addition, the term "including" and any of its variations are intended to cover non-exclusive inclusions. In this application, "at least one" refers to one or more, and "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, a and b, a and c, b and c or a and b and c, where a, b and c can be single or multiple. It is worth noting that "at least one" can also be interpreted as "one or more".

[0061] With the deployment of ASON and ROADM sites, there are more and more scenarios of dynamically adding and dropping channels in optical communication wavelength division networks. When adding and dropping waves, the optical power of the signal light at the input end of the optical amplifier will change dramatically. When adding waves, the optical power entering the optical amplifier increases, resulting in a decrease in the contribution of the pump light to each signal channel, a sudden decrease in the single-wavelength optical power, and a transient undershoot; when dropping waves, the optical power entering the optical amplifier suddenly decreases, resulting in an increase in the contribution of the excess pump light to the remaining signal channels, an increase in the single-wavelength optical power, and a transient overshoot.

[0062] Taking the EDFA in the existing network as an example, the above-mentioned Figure 1 The multi-stage amplification structure shown in the figure is used to pursue adjustable gain and better noise performance. Among them, the erbium fiber of the first-stage optical amplification structure 1021 is in a saturated state, resulting in an enhanced gain competition relationship between channels. The cascading of optical amplifiers in the communication network link, the increase in the number of wave additions and drops, the faster switching speed, and even fiber breakage will further increase the transient overshoot (including transient overshoot and transient undershoot) effect of the optical amplifier during the wave addition and drop process, resulting in transient interruption of services and affecting the normal operation of the system.

[0063] The current method of reducing the transient overshoot effect of the optical amplifier during the wave addition and drop process is to reduce the open-loop response time of the optical amplifier by the electric control circuit to change the pump power of each level of the optical amplifier structure, so that the change of the pump power keeps up with the change of the optical power at the input end of the optical amplifier as much as possible, so as to reduce the signal overshoot. Specifically, the input end detector detects the change of the optical power at the input end of the optical amplifier; then the configuration table is queried according to the current optical amplifier input power by the optical amplifier controller 101, and the pump power of each level of the optical amplifier structure is controlled by the corresponding pump current value. However, the open-loop response time of the electric control circuit cannot be reduced infinitely, and the response of the electric control circuit always lags behind the change of the optical power at the input end of the optical amplifier. Therefore, the current method can only suppress the transient overshoot of part of the optical amplifier, but cannot completely eliminate the transient overshoot phenomenon of the optical amplifier. Moreover, as the number of cascaded optical amplifiers increases, this transient overshoot effect will be continuously expanded, thereby affecting the network performance.

[0064] Therefore, in order to eliminate the transient overshoot phenomenon generated by the optical amplifier described above, an embodiment of the present application provides an optical amplifier for use in an optical communication wavelength division network. The optical amplifier provided by the present application can achieve the release or consumption of the pump energy required for each level of optical amplification structure in real time and dynamically by adaptively adjusting the energy of the complementary light corresponding to the signal light, thereby eliminating the transient overshoot phenomenon. It can be understood that since the response speed of the optical control circuit is better than the response speed of the electrical control circuit, in the optical amplifier provided by the embodiment of the present application, an optical control circuit can be introduced between any two levels of optical amplification structures, or between the optical amplifier input end and the optical amplifier output end. In this way, the optical control circuit can adjust its own loop attenuation size according to the VOA value fed back by the electrical control circuit, and then adaptively adjust the energy of the complementary light corresponding to the signal light according to the size of the input signal light, thereby releasing or consuming the pump energy required for each level of optical amplification structure in real time, and eliminating the transient overshoot phenomenon of the optical amplifier.

[0065] Figure 2a A schematic diagram of the structure of an optical amplifier is provided for the embodiment of the present application. Figure 2a It can be seen that the optical amplifier 10 may include an optical amplifier controller 101, a combiner 103, a first device 104, and an N-stage optical amplifier structure 102 arranged in a cascade manner. Among them, the above-mentioned N-stage optical amplifier structure 102 is used to amplify the signal light. The optical amplifier controller 101 is used to obtain a first gain value of the signal light, and determine a first VOA value and a first pump current value corresponding to the first gain value according to the association relationship. In addition, the optical amplifier controller 101 sends the first VOA value to the first device 104. The first device 104 is used to adjust the loop attenuation according to the first VOA value to emit complementary light corresponding to the signal light.

[0066] In this example, the described N-stage (N≥2, and N is an integer) optical amplifier structure is connected in a cascade manner, for example, Figure 2a The first-stage optical amplification structure 1021, the second-stage optical amplification structure 1022 ... and the N-stage optical amplification structure 102N are arranged in series. The first-stage optical amplification structure 1021 described can be understood as the first optical amplification structure arranged in the N-stage optical amplification structure 102, and the other second-stage optical amplification structures 1022 ... and the N-stage optical amplification structure 102N can be understood with reference to the first-stage optical amplification structure 1021, and no specific description is given. In addition, each stage of the optical amplification structure in the N-stage optical amplification structure 102 can amplify the signal light and provide gain for the signal light. Gain can be understood as the degree to which the signal light is amplified by the entire optical amplifier 10.

[0067] In addition, the optical amplifier controller 101 described is connected to the first device 104, and to each level of the optical amplifier structure in the N-level optical amplifier structure 102. Moreover, the combiner 103 described can be connected to the input end of the first-level optical amplifier structure 1021, or connected between the output end of the K-th level optical amplifier structure and the input end of the K+1-th level optical amplifier structure. The first end of the first device 104 described is connected to the combiner 103, and the second end of the first device 104 is connected to the output end of the N-th level optical amplifier structure 102N or connected between the output end of the M-th level optical amplifier structure and the input end of the M+1-th level optical amplifier structure, wherein 1≤K≤M, 2≤M≤N, and M and K are integers.

[0068] from Figure 2a It can be seen that the combiner 103 is connected between the output end of the first-stage optical amplification structure 1021 and the input end of the second-stage optical amplification structure 1022, and the second end of the first device 104 is connected to the output end of the N-stage optical amplification structure 102N, which is only a schematic description. In practical applications, the combiner 103 is not limited to Figure 2a The connection relationship shown in FIG. 1 is not limited to Figure 2a The connection relationship shown.

[0069] For example, see Figure 2b-2d , which is another structural diagram of the optical amplifier provided in the embodiment of the present application. As can be seen from 2b, the combiner 103 can be connected to the input end of the first-stage optical amplifier structure 1021. The first-stage optical amplifier structure 1021 described can refer to Figure 2a In addition, from Figure 2c It can be seen that the combiner 103 can also be connected between the output end of the N-1th optical amplification structure 102N-1 and the input end of the Nth optical amplification structure 102N.

[0070] For the connection relationship of the second end of the first device 104, please refer to Figure 2d To understand. Figure 2d It can be seen that the first device 104 can be connected between the output end of the second-stage optical amplification structure 1022 and the input end of the third-stage optical amplification structure 1023 .

[0071] It should be understood that there needs to be at least one optical amplification structure between the combiner 103 and the second end of the first device 104 .

[0072] by Figure 2aTaking the connection relationship between the combiner 103 and the first device 104 as an example, the electric control loop can be formed by the optical amplifier controller 101, the optical amplifier input end, the first-stage optical amplifier structure 1021, the combiner 103, the second-stage optical amplifier structure 1022 to the N-stage optical amplifier structure 102N, and the optical amplifier output end. Moreover, the loop formed by the combiner 103, the second-stage optical amplifier structure 1022 to the N-stage optical amplifier structure 102N, and the first device 104 can be understood as an optical control loop.

[0073] In order to make the signal light obtain a preset gain, the correlation between the first gain value of the signal light, the first variable optical attenuator (VOA) value and the first pump current value can be set in a configuration table, and the configuration table is stored in the optical amplifier controller 101. The first VOA value and the first pump current value described both correspond to the first gain value, and the first VOA value can be used to reflect the loop attenuation of the optical control loop where the first device 104 is located, and the first pump current value can reflect the pump current required by each level of optical amplifier structure.

[0074] In the process of controlling the pump power of each level of optical amplification structure by the first pump current value, and then controlling the pump energy of each level of optical amplification structure for the signal light, the optical amplifier controller 101 can attenuate the signal light through the first device 104 in the optical control loop under different gain settings in order to prevent transient overshoot in the amplification process of each level of optical amplification structure for the signal light. That is, the gain needs to be reduced by the same amount as the corresponding attenuation value increases; or the gain needs to be increased by the same amount as the corresponding attenuation value decreases, thereby achieving a flat output of the signal light.

[0075] Based on this, after the first gain value of the signal light and the associated relationship have been configured in the optical amplifier controller 101, the optical control circuit and the electrical control circuit are both in working state. In this way, the optical amplifier controller 101 can obtain the first gain value of the signal light from the configuration table, and determine the first VOA value and the first pump current value according to the associated relationship. On the one hand, the optical amplifier controller 101 needs to feed back the first VOA value to the first device 104; on the other hand, the optical amplifier controller 101 also needs to adjust the pump power in each level of the optical amplifier structure according to the first pump current value.

[0076] Before the addition and dropout wave occurs, the first device 104 in the optical control loop can first adjust the loop attenuation size according to the first VOA value, so as to ensure that the complementary light corresponding to the signal light can maintain normal operation. In this way, when the addition and dropout wave occurs, due to the fast response speed of the optical control loop, in the process of the optical amplifier controller 101 adjusting the pump power in each level of the optical amplifier structure according to the first pump current value, the complementary light can release or consume the pump energy of each level of the optical amplifier structure enabled by the first pump current value according to the optical amplifier input power of the signal light, thereby eliminating the phenomenon of transient overshoot of the optical amplifier generated by the signal light in each level of the optical amplifier structure. The complementary light described can be understood as the lasing light formed in the optical control loop by the noise generated by the optical amplifier structure at each level.

[0077] It should be understood that the optical control circuit described above may vary depending on the connection positions of the combiner 103 and the first device 104. Figure 2b In the optical amplifier 10 shown in FIG. 1 , the optical control circuit at this time can be regarded as a circuit formed by connecting the combiner 103, the first optical amplifier structure 1021, the second optical amplifier structure 1022 ... the Nth optical amplifier structure 102N, and the first device 104. Alternatively, in the above Figure 2c In the optical amplifier 10 shown in FIG. 1 , the optical control circuit at this time can be regarded as a circuit formed by connecting the combiner 103, the Nth stage optical amplification structure 102N and the first device 104. Alternatively, in the above Figure 2d In the optical amplifier 10 shown, the loop formed by connecting the combiner 103, the second-stage optical amplification structure 1022, and the first device 104 can also be understood as an optical control loop, which is not specifically limited in this application.

[0078] In addition to the above Figure 2b In addition to the case where the combiner 103 is connected to the input end of the first-stage optical amplification structure 1021, Figure 2a , Figure 2c-2d The optical control circuit shown, or the optical control circuit corresponding to the optical control circuit that connects the combiner 103 between the output end of the K-th optical amplifier structure and the input end of the K+1-th optical amplifier structure, can eliminate the instantaneous overshoot of the optical amplifier 10 without degrading the noise performance of the optical amplifier 10. In other words, complementary light is introduced between the intermediate optical amplifier structures of the entire optical amplifier 10, or between the intermediate optical amplifier structure and the output end of the optical amplifier to eliminate the pump energy of the signal light in each optical amplifier structure, thereby eliminating the instantaneous overshoot of the optical amplifier 10 without degrading the noise performance of the optical amplifier 10. The intermediate optical amplifier structure described can be understood as the remaining optical amplifier structures except the first optical amplifier structure 1021, which is not limited here.

[0079] Figure 3 Another schematic diagram of the structure of the optical amplifier provided in this embodiment. Figure 3 It can be seen that when N=3, the optical control loop can be regarded as a loop formed by connecting the combiner 103, the second-stage optical amplifier structure 1022, the third-stage optical amplifier structure 1023, and the first device 104. Moreover, when the third-stage optical amplifier structure 1023 outputs the signal light, the corresponding optical amplifier noise index will not degrade the noise performance corresponding to the signal light output by the first-stage optical amplifier structure 1021. For details, refer to the following formula:

[0080]

[0081] Among them, NF is the optical noise index corresponding to the third-stage optical amplifier structure 1023, NF1 is the optical noise index corresponding to the first-stage optical amplifier structure 1021, NF2 is the optical noise index corresponding to the second-stage optical amplifier structure 1022, L is the loss, and G1 is the gain provided by the first-stage optical amplifier structure 1021.

[0082] It can be seen from the above formula that the introduced loss will have a small impact on NF1, especially when the introduced loss is much smaller than G1, the noise performance of the original optical amplifier will hardly be degraded. Moreover, since the optical control loop is not formed at the input end of the first-stage optical amplifier structure 1021, the adjustment range of the optical amplifier input power of the entire optical amplifier 10 will not be reduced, and the dynamic adjustable range of the gain of the signal light can be guaranteed. In addition, between the optical amplifier structures of the intermediate stages of the entire optical amplifier 10, or between the optical amplifier structure at the output end and the intermediate stage of the optical amplifier, complementary light corresponding to the signal light is introduced to eliminate the pump energy of the signal light in the optical amplifier structures of each stage, thereby eliminating the instantaneous overshoot of the optical amplifier 10 without degrading the gain performance of the optical amplifier 10. The above mainly describes that the optical amplifier controller 101 feeds back the constant first gain value in the configuration table to the first device 104, so that the first device 104 can adjust the loop attenuation size according to the first VOA value to emit complementary light corresponding to the signal light, thereby eliminating the instantaneous overshoot of the optical amplifier. On the basis of eliminating the transient overshoot of the optical amplifier, in order for each level of optical amplifier structure to still provide stable gain for the signal light, the optical amplifier controller 101 also needs to adjust the corresponding VOA value in real time according to the gain setting value and the configuration table when the gain setting value changes, so as to ensure the normal operation of the optical control loop. Figure 2aBased on the optical amplifier 10 shown, in some other optional examples, the optical amplifier controller 101 can also be used to: obtain a second gain value of the signal light, and a second VOA value and a second pump current value corresponding to the second gain value. In addition, when the first gain value is not equal to the second gain value, the optical amplifier controller 101 updates the first gain value to the second gain value, updates the first VOA value to the second VOA value, and updates the first pump current value to the second pump current value.

[0083] In this example, when the loss of the optical communication system changes, it is necessary to provide corresponding gain through each level of optical amplification structure to compensate for the loss. Therefore, in the process of compensating the loss through gain, the gain will change with the change of loss; and the stability of the gain needs to be achieved through complementary light corresponding to the signal light, and the lasing complementary light needs to be achieved through the loop attenuation size, so at this time, the VOA value needs to be updated by the optical amplifier controller 101.

[0084] Specifically, the optical amplifier controller 101 first needs to obtain the second gain value of the signal light determined based on the loss, and obtain the second VOA value and the second pump current value corresponding to the second gain value. In this way, the optical amplifier controller 101 determines whether the first gain value is equal to the second gain value. If the first gain value is not equal to the second gain value, the optical amplifier controller 101 needs to update the first gain value in the configuration table to the second gain value, and update the first VOA value to the second VOA value, and update the first pump current value to the second pump current value, thereby effectively realizing the dynamic adjustment of the gain of the signal light.

[0085] For example, in the current configuration table, the gain setting value of the signal light is the first gain value, such as: 10db. If based on the loss, it is hoped that the final signal light gain can be changed to 13db. At this time, the optical amplifier controller 101 needs to obtain the second gain value (i.e.: 13db), update the 10db in the original configuration table to 13db, and update the corresponding first VOA value to the VOA value corresponding to 13db, and update the first pump current value to the pump current value corresponding to 13db. It should be understood that the 10db and 13db described are only a schematic description and are not limited in actual applications.

[0086] In other examples, after the optical amplifier controller 101 updates the VOA value and the pump current value, the optical amplifier controller 101 can also control and adjust the gain of the signal light through an open-loop adjustment operation. Specifically, the optical amplifier controller 101 can also obtain the optical amplifier input power of the signal light at the current moment and the optical amplifier input power at the previous moment, and determine the change of the optical amplifier input power according to the optical amplifier input power and the optical amplifier input power at the previous moment. Then, when the change of the optical amplifier input power is greater than the open-loop threshold, the optical amplifier controller 101 controls the pump power of the optical amplifier structure at each level according to the second pump current value, and sends the second VOA value to the first device 104. The first device 104 is also used to adjust the loop attenuation according to the second VOA value.

[0087] In this example, after the optical amplifier controller 101 updates the second VOA value and the second pump current value, it can know how much gain is needed to compensate for the loss. At this time, the optical amplifier controller 101 can obtain the optical amplifier input power of the signal light at the current moment and the optical amplifier input power at the previous moment, and determine the change of the optical amplifier input power according to the optical amplifier input power at the current moment and the optical amplifier input power at the previous moment, that is: Wherein, K is the change of the OA input power, A is the OA input power at the current moment, and B is the OA input power at the previous moment.

[0088] In this way, the optical amplifier controller 101 can perform an open-loop adjustment operation when the optical amplifier input power change is greater than the open-loop threshold. It should be noted that the optical amplifier input power change described can be understood as the value of the optical amplifier input power change caused by the addition and drop of the signal light when entering the optical amplifier 10 from the optical amplifier input end, that is, the multiple of the change. In addition, when the optical amplifier input power change exceeds a certain preset value, the aforementioned open-loop adjustment operation is triggered, and at this time, the certain preset value can be understood as the open-loop threshold.

[0089] In addition, when the change in the OA input power is less than or equal to the open-loop threshold, the OA controller 101 may also perform a closed-loop regulation operation. The specific closed-loop regulation operation described may refer to the following Figure 4b The content described above can be understood without further elaboration here.

[0090] Figure 4a A schematic diagram of open-loop regulation provided in an embodiment of the present application. Figure 4aIt can be seen that the optical amplifier controller 101 determines the gain setting value in the configuration table at this time, that is, the second gain value, by querying the configuration table. Then, the optical amplifier controller 101 determines the second pump current value and the second VOA value based on the second gain value and the association relationship. On the one hand, the optical amplifier controller 101 can control the pump power of each level of the optical amplifier structure according to the second pump current value; on the other hand, the optical amplifier controller 101 also needs to feed back the second VOA value to the first device 104, so that the first device 104 can also adjust the loop attenuation according to the second value.

[0091] In this way, the first device 104 can first adjust the loop attenuation size according to the second VOA value, so that the complementary light can work normally. In the process of the optical amplifier controller 101 adjusting the pump power in each level of the optical amplifier structure according to the second pump current value, the normally working complementary light can release or consume the pump energy of each level of the optical amplifier structure enabled by the second pump current value. Not only can the phenomenon of optical amplifier transient overshoot generated by the signal light in each level of the optical amplifier structure be eliminated, but also the gain of the signal light can be adjusted to be close to the set second gain value.

[0092] In other examples, in order to accurately control the stability of the gain, the optical amplifier controller 101 is also used to obtain the optical amplifier output power of the signal light at the current moment, and calculate the actual gain value of the signal light based on the optical amplifier input power at the current moment and the optical amplifier output power at the current moment. Then the optical amplifier controller 101 calculates the gain difference value between the actual gain value and the second gain value. And, when the gain difference value is greater than or equal to the closed-loop threshold, the optical amplifier controller 101 adjusts the third pump current value corresponding to the actual gain value according to the gain difference value, so as to control the pump power of the optical amplifier structure at each level, and adjusts the third VOA value corresponding to the actual gain value according to the gain difference value. Wherein, the closed-loop threshold is less than the open-loop threshold. The first device 104 is also used to adjust the loop attenuation size according to the third VOA value.

[0093] That is to say, after performing the open-loop adjustment, the optical amplifier controller 101 can also obtain the optical amplifier output power of the signal light at the current moment, and calculate the actual gain value of the signal light in combination with the optical amplifier input power at the current moment described above. Then, the optical amplifier controller 101 processes the actual gain value with the second gain value in the configuration table to obtain a gain difference value. If the gain difference value is greater than or equal to the closed-loop threshold, the optical amplifier controller 101 can perform a closed-loop adjustment operation to fine-tune the pump current value corresponding to the pump power used to control each level of the optical amplifier structure, and fine-tune the VOA value.

[0094] It should be noted that when the change in the input power of the optical amplifier exceeds a certain preset value, the aforementioned closed-loop adjustment operation is triggered. At this time, the certain preset value can be understood as a closed-loop threshold. Generally, the closed-loop threshold described is smaller than the open-loop threshold.

[0095] Figure 4b A schematic diagram of closed-loop regulation provided in an embodiment of the present application. Figure 4b It can be seen that when the gain difference value is greater than or equal to the closed-loop threshold, the optical amplifier controller 101 can adjust the third pump current value corresponding to the actual gain value according to the gain difference value, and adjust the third VOA value corresponding to the actual gain value according to the gain difference value. And by repeatedly performing the closed-loop adjustment operation, the third pump current value and the third VOA value are fine-tuned until the gain difference value between the actual gain value and the second gain value in the configuration table is less than the closed-loop threshold. In other words, the adjusted pump current value corresponding to the actual gain value can approach the second pump current value corresponding to the second gain value set in the configuration table, and the adjusted third VOA value can also approach the VOA value corresponding to the second gain value set in the configuration table, which can indicate that the gain of the signal light can be accurately controlled and kept stable at this time.

[0096] Therefore, the optical amplifier controller 101 can control the pump power of each level of the optical amplifier structure according to the adjusted third pump current value; and, the optical amplifier controller 101 can also feed back the adjusted third VOA value to the first device 104, so that the first device 104 can also adjust the loop attenuation size according to the adjusted third VOA value.

[0097] In this way, the first device 104 can first adjust the loop attenuation size according to the adjusted third VOA value, so that the complementary light corresponding to the signal light can work normally. And in the process of the optical amplifier controller 101 adjusting the pump power in each level of optical amplifier structure according to the adjusted third pump current value, the complementary light can release or consume the pump energy of each level of optical amplifier structure under the enablement of the pump current value corresponding to the second gain value. Not only can the gain of the signal light be accurately controlled in real time to maintain the stability of the gain, but also the phenomenon of optical amplifier transient overshoot generated by the signal light in each level of optical amplifier structure can be eliminated.

[0098] Figure 5a FIG. 1 is another schematic diagram of the structure of the optical amplifier provided in the embodiment of the present application. Figure 5a It can be seen that the optical amplifier 10 may further include a second device 105, wherein the second device 105 is connected to the output end of the N-th optical amplification structure 102N, or is connected between the output end of the M-th optical amplification structure and the input end of the M+1-th optical amplification structure, and the second device 105 is also connected to the first device 104;

[0099] The second device 105 is used to determine the wavelength band of the complementary light, or determine the split power of the complementary light.

[0100] In this example, the second device 105 can be a component of the aforementioned optical control circuit. The second device 105 is used to determine the wavelength band of the complementary light or determine the splitting power of the complementary light, so as to provide a candidate range of the lasing wavelength or the lasing power during the lasing of the complementary light.

[0101] Need to explain, Figure 5a The second device 105 described in the above Figure 2a-2d ,as well as Figure 3 In the embodiment of the present application, only the second device 105 is added to Figure 2a The structure of the optical amplifier 10 is described as an example.

[0102] in addition, Figure 5a The second device 105 described as being connected to the output end of the Nth optical amplification structure 102N is merely a schematic description. In practical applications, the second device 105 is not limited to Figure 5a For example, Figure 5b Another structural diagram of the optical amplifier provided in the embodiment of the present application. As can be seen from Figure 5b, the second device 105 can be connected between the output end of the N-1th optical amplifier structure 102N-1 and the input end of the Nth optical amplifier structure 102N, which is not limited here.

[0103] It is worth noting that there always needs to be at least one optical amplification structure between the second device 105 and the combiner 103 .

[0104] In addition, in some optional examples, in the above Figure 5a or Figure 5b Based on the structure of the optical amplifier 10 described above, a variety of different devices can be used to perform the function performed by the second device 105. For example, a splitter or a coupler can be used to perform the function performed by the second device 105. The following will be described from different embodiments:

[0105] (1) The second device 105 includes a first splitter 1051 .

[0106] Figure 6a Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Figure 6aIt can be seen that the second device 105 may include a first wave splitter 1051. The first wave splitter 1051 is used to separate the wavelength band of the signal light and the wavelength band of the complementary light to determine the wavelength band of the complementary light; or the first wave splitter 1051 is used to generate a filter spectrum line and obtain a spontaneous emission ASE spectrum line modulated by the N-stage optical amplification structure, and determine the wavelength of the complementary light based on the filter spectrum line and the spontaneous emission ASE spectrum line.

[0107] In this example, in the above Figure 5a Based on the structure of the optical amplifier 10 described above, since the signal light and the complementary light output by the N-th optical amplifier structure 102N are mixed together. Therefore, after the mixed signal light and complementary light pass through the first splitter 1051, the first splitter 1051 can separate the wavelength band of the signal light and the wavelength band of the complementary light, thereby obtaining the wavelength band of the complementary light. Subsequently, the first splitter 1051 feeds back the wavelength band of the complementary light to the first device 104. In this way, the first device 104 can select a lasing wavelength from the wavelength band of the complementary light, and then after adjusting the loop attenuation, the complementary light is lased according to the lasing wavelength of the complementary light.

[0108] In other words, since each level of optical amplification structure includes a gain flattening filter (GFF), the spontaneous emission (amplified spontaneous emission, ASE) spectrum line of each level of optical amplification structure itself will be modulated. When the signal light is output from the N-th level optical amplification structure 102N and passes through the first splitter 1051, the first splitter 1051 will also generate a corresponding filter spectrum line. Therefore, after obtaining the ASE spectrum line modulated by the N-th level optical amplification structure 102, the first splitter 1051 can determine the equivalent filter band in combination with the filter spectrum line, and then determine the wavelength of the complementary light. In this way, the first device 104 can directly laser the complementary light according to the wavelength of the complementary light after adjusting the loop attenuation.

[0109] The equivalent filter band described can be understood as the filter band obtained when the ASE spectrum line intersects the filter spectrum line. For details, please refer to Figure 7 A schematic diagram of the equivalent filter band is shown for understanding.

[0110] (2) The second device 105 includes a coupler 1052 .

[0111] Figure 6b Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Figure 6b It can be seen that the second device 105 may include a coupler 1052. The coupler 1052 is used to determine the splitting power of the signal light and the complementary light.

[0112] In this example, in the above Figure 5a Based on the structure of the optical amplifier 10 described above, since the signal light and the complementary light outputted by the N-th optical amplifier structure 102N are mixed together, after the mixed signal light and the complementary light pass through the coupler 1052, the coupler 1052 cannot filter out the wavelength band of the complementary light, but determines the splitting power 1052 of the mixed signal light and the complementary light, and feeds it back to the first device 104. Subsequently, the first device 104 filters out the optical power of the complementary light from the splitting power of the signal light and the complementary light, and then after adjusting the loop attenuation, the complementary light is lasered according to the optical power of the complementary light.

[0113] In addition, in some optional examples, in the above Figure 2a-Figure 6b Based on the structure of the optical amplifier 10 described above, a variety of different devices can be used to perform the function performed by the first device 104. For example, an adjustable optical attenuator and a filter can be used to perform the function performed by the first device 104, or only an adjustable optical attenuator can be used to perform the function performed by the first device 104. The following will be described from different embodiments:

[0114] (1) The first device 104 includes a first adjustable optical attenuator 1041 and a first filter 1042 .

[0115] Figure 8a Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Figure 8a It can be seen that the first device 104 may include a first adjustable optical attenuator 1041 and a first filter 1042. The first filter 1042 is used to select a lasing wavelength from the wavelength band of the complementary light, so as to lasing the complementary light at the lasing wavelength after the first adjustable optical attenuator 1041 adjusts the loop attenuation.

[0116] In this example, in the above Figure 6aBased on the structure of the described optical amplifier 10, since the signal light and the complementary light output by the Nth-stage optical amplification structure 102N are mixed together. Therefore, after the mixed signal light and complementary light pass through the first demultiplexer 1051, the first demultiplexer 1051 can separate the wavelength bands of the signal light and the complementary light, thereby obtaining the wavelength band of the complementary light. Subsequently, the first filter 1042 can select any lasing wavelength from the wavelength band of the complementary light, and after the first adjustable optical attenuator 1041 adjusts the loop attenuation magnitude, the complementary light is lasered according to the lasing wavelength, so that the complementary light can release or consume the pump energy of each stage of the optical amplification structure under the enabling of the second pump current value. It can not only accurately control the gain of the signal light in real time and maintain the stability of the gain, but also eliminate the phenomenon of optical amplification transient overshoot generated by the signal light in each stage of the optical amplification structure.

[0117] In addition, in this embodiment, the lasing of the complementary light can be carried out either at the long-wavelength position or at the short-wavelength position, and no specific limitation is described here.

[0118] (2). The first device 104 includes a second adjustable optical attenuator 1043.

[0119] Figure 8b It is another structural schematic diagram of the optical amplifier provided by the embodiment of the present application. From Figure 8b it can be seen that the first device 104 may include a second adjustable optical attenuator 1043. Among them, the second adjustable optical attenuator 1043 is used to laser the complementary light according to the wavelength of the complementary light after adjusting the loop attenuation magnitude.

[0120] In this example, based on the structure of the optical amplifier 10 described above Figure 6a since the first demultiplexer 1051 can, after obtaining the ASE spectral lines modulated by the N-stage optical amplification structure, determine the equivalent filter band in combination with the filter spectral lines and determine the wavelength of the complementary light. Further, after the second adjustable optical attenuator 1043 adjusts the loop attenuation magnitude, the complementary light can still be lasered according to the wavelength of the complementary light determined by the first demultiplexer 1051, so that the complementary light can release or consume the pump energy of each stage of the optical amplification structure under the enabling of the second pump current value. It can not only accurately control the gain of the signal light in real time and maintain the stability of the gain, but also eliminate the phenomenon of optical amplification transient overshoot generated by the signal light in each stage of the optical amplification structure. In addition, in this embodiment, the lasing of the complementary light can be carried out either at the long-wavelength position or at the short-wavelength position, and no specific limitation is described here.

[0121] Compared with the first device 104 in the optical amplifier 10 described above Figure 8a this Figure 8bThe first device 104 in the optical amplifier 10 shown does not include the first filter 1042. Therefore, in order to be able to laser the complementary light after the second adjustable optical attenuator 1043 adjusts the loop attenuation according to the VOA value fed back by the optical amplifier controller 101, the wavelength of the complementary light can be directly determined by using the spontaneous emission ASE spectrum line and the filter spectrum line. Figure 8a The first filter 1041 shown selects a suitable lasing wavelength from the wavelength band of complementary light, saving cost and volume.

[0122] (3) The first device 104 includes a third adjustable optical attenuator 1044 and a second filter 1045 .

[0123] Figure 8c Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Figure 8c It can be seen that the first device 104 may include a third adjustable optical attenuator 1044 and a second filter 1045. The second filter 1045 is used to determine the optical power of the complementary light from the split optical power of the signal light and the complementary light, so as to laser the complementary light according to the optical power of the complementary light after the third adjustable optical attenuator 1044 adjusts the loop attenuation.

[0124] In this example, in the above Figure 6b Based on the structure of the optical amplifier 10 described, the signal light and complementary light output by the Nth optical amplifier structure 102N are mixed together. Therefore, after the mixed signal light and complementary light pass through the coupler 1052, the coupler 1052 cannot filter out the wavelength band of the complementary light, but determines the splitting power of the mixed signal light and complementary light, and feeds it back to the second filter 1045. Subsequently, the second filter 1045 can filter out the optical power of the complementary light from the splitting power of the signal light and complementary light. Moreover, after the third adjustable optical attenuator 1044 adjusts the loop attenuation size, the second filter 1045 excites the complementary light according to the optical power of the complementary light, so that the complementary light can release or consume the pumping energy of the optical amplifier structures at various levels under the enablement of the second pump current value. Not only can the gain of the signal light be accurately controlled in real time to maintain the stability of the gain, but also the phenomenon of transient overshoot of the optical amplification generated by the signal light in the optical amplifier structures at various levels can be eliminated. In addition, in this embodiment, the complementary laser light can be lasered at a long-wave position or a short-wave position, which is not limited here.

[0125] In some other optional examples, Figure 8d Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Figure 8dIt can be seen that the optical amplifier 10 further includes a third filter 106 and an optical amplifier output terminal 107, and the third filter 106 is connected between the optical amplifier output terminal 107 and the optical amplifier controller 101. The third filter 106 is used to filter the complementary light before the optical amplifier controller 101 obtains the optical amplifier output power of the signal light at the current moment.

[0126] In the above Figure 8c On the basis of the optical amplifier 10 shown, since the signal light and the complementary light output by the N-th optical amplifier structure 102N are mixed together, the output end detector detects the optical amplifier output power of the signal light at the current moment, which should be the detection of the independent signal light. Therefore, before the optical amplifier controller 101 obtains the optical amplifier output power of the signal light at the current moment from the output end detector, the signal light and the complementary light should be separated by the third filter 106 to ensure that the independent signal light is obtained, and then ensure that the accurate optical amplifier output power of the signal light at the current moment can be detected later, so as to ensure that no error occurs in the process of the optical amplifier controller 101 performing closed-loop regulation.

[0127] In some other optional examples, Fig. 9 Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Fig. 9 It can be seen that the optical amplifier 10 further includes an input end detector 108, a first end of the input end detector 108 is connected to the input end of the first-stage optical amplifier structure 1021, and a second end of the input end detector 108 is connected to the optical amplifier controller 101. The input end detector 108 is used to detect the optical amplifier input power of the signal light at the current moment, and send the optical amplifier input power at the current moment to the optical amplifier controller 101.

[0128] In some other optional examples, Fig.10 Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Fig.10 It can be seen that the optical amplifier 10 further includes an output end detector 109, a first end of which is connected to the output end of the Nth optical amplifier structure 102N or the second device 105, and a second end of which is connected to the optical amplifier controller 101. The output end detector 109 is used to detect the optical amplifier output power of the signal light at the current moment, and send the optical amplifier output power at the current moment to the optical amplifier controller 101.

[0129] In some other optional examples, Fig.11 Another structural schematic diagram of an optical amplifier provided in an embodiment of the present application. Fig.11It can be seen that the optical amplifier 10 further includes an optical amplifier input terminal 1010 , and the optical amplifier input terminal 1010 is connected to the input terminal of the first-stage optical amplifier structure 1021 .

[0130] For ease of understanding, the following Figure 12a-12b The spectrum condition after applying the optical amplifier 10 provided in this embodiment will be described from the perspective of spectrum. Fig.12a This is a schematic diagram of the spectrum of the intermediate-level optical amplification structure. Fig.12a It can be seen that since the complementary light is generated by looping back the ASE light outside the service channel using the optical control circuit described above, the complementary light will not occupy the service channel of the transmission signal light, and will not affect the quality of the signal light. Fig.12a The complementary light shown can be emitted at either a long-wave position or a short-wave position, which is not limited here.

[0131] Figure 12b 1 is a schematic diagram of the spectrum of the output end of the optical amplifier. Due to the enabling function of the second device 105, such as the first splitter 1051, the complementary light is cut off at the output end of the optical amplifier. Figure 12b It can be seen that the output end of the optical amplifier only outputs the signal light transmitted through the service channel.

[0132] Compared with the existing solution that can only partially eliminate the transient overshoot effect of the optical amplifier through the electric control circuit, the optical amplifier 10 provided in this embodiment can completely eliminate the transient overshoot effect of the optical amplifier and provide stable gain. Fig.13a A schematic diagram of transient overshoot generated by the existing solution during the addition and dropout process, and Fig.13b A schematic diagram of transient overshoot generated during the addition and dropout process provided in this embodiment. Fig.13a It can be seen that when applying the existing solution to eliminate the transient overshoot effect of the optical amplifier, when the dropout wave occurs, the optical amplifier power amplifier in the signal channel will first surge and oscillate, and then recover to stability. The overshoot process will be amplified in the optical communication system, even exceeding 10dB, resulting in a longer steady-state recovery time, which will affect the stability of the optical communication system. Compared with the existing solution, Fig.13b It can be seen that by applying the optical amplifier 10 provided in the present application, the transient overshoot of the optical amplifier caused by the addition and drop of the wave in the optical communication system is eliminated, and the time for the system to recover stability is greatly shortened.

[0133] The above mainly describes the structure of the optical amplifier, and the optical communication system will be described below. Fig.14a A schematic diagram of the structure of the optical communication system provided in this embodiment. Fig.14aIt can be seen that the optical communication system may include an optical transmitter 20 , an optical receiver 30 , a first optical multiplexer / demultiplexer 40 , a second optical multiplexer / demultiplexer 50 , an optical fiber link 60 and at least one optical amplifier 10 .

[0134] The optical transmitter 20 generates multiple signal lights, which can form wavelength division multiplexing signals after being multiplexed by the first optical multiplexer / demultiplexer 40. Then, the wavelength division multiplexing signals are transmitted to the optical fiber link 60, and the loss is compensated by at least one optical amplifier 10. Finally, after being demultiplexed by the second optical multiplexer / demultiplexer 50, they are received by the optical receiver 30.

[0135] It should be noted that the optical amplifier 10 described can refer to the aforementioned Figures 2a to 11 The optical amplifier 10 described above is understood. Fig.14a In the optical communication system shown in the figure, only a fiber link with a spacing of 3 spans is used. Figures 2a to 11 Any of the optical amplifiers 10 described in the embodiment can eliminate the transient overshoot of the optical amplifier of the system caused by the addition of the drop wave signal, and maintain the stability of the entire optical communication system. However, in practical applications, it is also possible to use one optical fiber link with a span of w (w ≥ 1, w is an integer) Figures 2a to 11 Any one of the optical amplifiers 10 described herein is used to eliminate or alleviate the transient overshoot phenomenon of the system optical amplifier caused by adding a dropout signal.

[0136] Fig.14b Another structural diagram of the optical communication system provided in this embodiment. Fig.14b It can be seen that the optical communication system may include an optical transmitter 20, an optical receiver 30, a first optical multiplexer / demultiplexer 40, a second optical multiplexer / demultiplexer 50, a filter device 70, an optical fiber link 60, and at least one optical amplifier 10. The optical transmitter 20 generates multiple signal lights, which can form a wavelength division multiplexing signal after multiplexing by the first optical multiplexer / demultiplexer 30. Then, the wavelength division multiplexing signal enters the optical fiber link 60, and the loss is compensated by at least one optical amplifier 10. Finally, after filtering by the filter device 70 and demultiplexing by the second optical multiplexer / demultiplexer 50, it is received by the optical receiver 30.

[0137] It should be noted that the optical amplifier 10 described can refer to the aforementioned Figure 8c to Figure 8d The optical amplifier 10 is described for understanding. Figure 8c to Figure 8d The optical amplifier described is used in Fig.14bWhen the optical communication system shown in the figure is used, it can be placed at the start end of the optical multiplex section (optical multiplex section, OMS) of the optical communication system, and the remaining optical amplifiers at various levels can use the optical amplifiers in the existing scheme. In this way, complementary light is generated inside the optical amplifier 10 to which this embodiment is applied, and is output together with the signal light and transmitted in the OMS section. As the complementary light is attenuated in the optical fiber link 60 as the signal light is, and is amplified in the remaining optical amplifiers at various levels, the complementary light generated by the optical amplifier 10 of this embodiment of the remaining optical amplifiers at various levels eliminates the transient overshoot effect, thereby maintaining the power stability of the signal light of the overall optical communication system. In addition, it is also necessary to use a filter device 70 to filter out the complementary light at the tail end of the OMS section and before the second optical multiplexer / demultiplexer 50 is down-converted, so that only the signal light is output at the tail end of the OMS.

[0138] Based on the above embodiments, the present application also provides a method for processing transient overshoot. Figure 2a-Figure 11 The provided optical amplifier provides a detailed introduction to the processing method of the present application. For details not detailed in the method embodiment, please refer to the above-mentioned embodiment of the optical amplifier 10 for understanding.

[0139] Fig.15 A schematic diagram of a process flow of a transient overshoot processing method provided in an embodiment of the present application. The processing method can be applied to the above Figure 2a-Figure 11 The optical amplifier 10 shown. For details, see Figure 2a-Figure 11 It can be known that the optical amplifier may include: an optical amplifier controller, a combiner, a first device, and N-stage optical amplifier structures arranged in a cascade manner. The optical amplifier controller is connected to the first device, and to each stage of the optical amplifier structures in the N-stage optical amplifier structure. The combiner is connected to the input end of the first-stage optical amplifier structure, or is connected between the output end of the K-th stage optical amplifier structure and the input end of the K+1-th stage optical amplifier structure. The first end of the first device is connected to the combiner, and the second end of the first device is connected to the output end of the N-stage optical amplifier structure, or is connected between the output end of the M-th stage optical amplifier structure and the input end of the M+1-th stage optical amplifier structure, N≥2, 1≤K≤M, 2≤M≤N, and N, M, and K are integers. The N-stage optical amplifier structure is used to amplify signal light. Accordingly, as Fig.15 As shown, the processing method may include the following steps:

[0140] 1501. Obtain a first gain value of signal light.

[0141] 1502. Determine a first VOA value and a first pump current value corresponding to the first gain value according to the first gain value and the associated relationship. The associated relationship is the relationship among the first gain value, the first VOA value and the first pump current value. The first VOA value reflects the loop attenuation of the first device. The first pump current value reflects the pump current required for each level of the optical amplifier structure in the N-level optical amplifier structure.

[0142] In this example, the first VOA value and the first pump current value described both correspond to the first gain value. In addition, the first VOA value can be used to reflect the loop attenuation of the optical control loop where the first device in the optical amplifier is located, and the first pump current value can reflect the pump current required by each level of optical amplification structure. Therefore, when the user wants the signal light to obtain a preset gain, the association between the first gain value, the first VOA value, and the first pump current value of the signal light can be set in a configuration table, and the configuration table will be stored. Then, the optical amplifier can determine the first VOA value and the first pump current value corresponding to the first gain value based on the first gain value and the association relationship.

[0143] 1503. Adjust loop attenuation according to the first VOA value to emit complementary light corresponding to the signal light.

[0144] In this example, in the process of controlling the pump power of each optical amplification structure in the optical amplifier by the first pump current value, and then controlling the pump energy of each optical amplification structure for the signal light, in order to prevent transient overshoot in the amplification process of each optical amplification structure for the signal light, the signal light can be attenuated under different gain settings. That is, the gain needs to be reduced by the same amount as the corresponding attenuation needs to be increased; or the gain needs to be increased by the same amount as the corresponding attenuation needs to be reduced, thereby achieving a flat output of the signal light.

[0145] Therefore, before the dropout wave occurs, the loop attenuation can be adjusted according to the first VOA value to ensure that the complementary light corresponding to the signal light can maintain normal operation. In this way, when the dropout wave occurs, in the process of adjusting the pump power in each level of optical amplification structure according to the first pump current value, the complementary light can release or consume the pump energy of each level of optical amplification structure enabled by the first pump current value according to the optical amplifier input power of the signal light, thereby eliminating the phenomenon of transient overshoot of the optical amplifier generated by the signal light in each level of optical amplifier structure. The complementary light described can be understood as the lasing light formed in the optical control circuit by the noise generated by the optical amplifier structure at each level.

[0146] In some optional examples, the processing method may further include: obtaining a second gain value of the signal light, and a second VOA value and a second pump current value corresponding to the second gain value. Furthermore, when the first gain value is not equal to the second gain value, updating the first gain value to the second gain value, updating the first VOA value to the second VOA value, and updating the first pump current value to the second pump current value.

[0147] In this example, on the basis of eliminating the phenomenon of transient overshoot of optical amplifier, in order to further provide stable gain for signal light, it is also necessary to adjust the corresponding VOA value in real time according to the gain setting value and the configuration table when the gain setting value changes, so as to ensure that the complementary light can work normally. Therefore, it is necessary to first obtain the second gain value of the signal light, and obtain the second VOA value and the second pump current value corresponding to the second gain value. In this way, it is determined whether the first gain value is equal to the second gain value. If the first gain value is not equal to the second gain value, it is necessary to update the first gain value in the configuration table to the second gain value, and update the first VOA value to the second VOA value, and update the first pump current value to the second pump current value, so as to effectively realize the dynamic adjustment of the gain of the signal light.

[0148] In some optional examples, the processing method may also include: obtaining the optical amplifier input power of the signal light at a current moment and the optical amplifier input power at a previous moment; determining the change in the optical amplifier input power based on the optical amplifier input power at a current moment and the optical amplifier input power at the previous moment; when the change in the optical amplifier input power is greater than an open-loop threshold, controlling the pump power of each stage of the optical amplifier structure according to a second pump current value, and adjusting the loop attenuation according to a second VOA value.

[0149] In this example, when the change in the optical amplifier input power is greater than the open-loop threshold, the optical amplifier can perform an open-loop regulation operation. The open-loop regulation operation described in detail can be found in the aforementioned Figure 4a In addition, the optical amplifier input power variation, open-loop threshold, etc., described above can also be understood by referring to the above content, and will not be described here.

[0150] In some optional examples, the processing method may also include: obtaining the optical amplifier output power of the signal light at the current moment; calculating the actual gain value of the signal light based on the optical amplifier input power at the current moment and the optical amplifier output power at the current moment; calculating the gain difference value between the actual gain value and the second gain value; when the gain difference value is greater than or equal to a closed-loop threshold, adjusting the pump current value corresponding to the actual gain value according to the gain difference value to control the pump power of each level of the optical amplifier structure, and adjusting the third VOA value corresponding to the actual gain value according to the gain difference value, wherein the closed-loop threshold is less than the open-loop threshold; and adjusting the loop attenuation size according to the third VOA value corresponding to the actual gain value.

[0151] In this example, in order to accurately control the stability of the gain, the optical amplifier can also perform a closed-loop regulation operation. The closed-loop regulation operation described in detail can be found in the aforementioned Figure 4b In addition, the closed-loop threshold described can also be understood by referring to the above content, which is not described here.

[0152] It should be noted that the contents of the above steps 1501-1503 can also be specifically referred to the above Figure 2a-Figure 11 You can understand the contents described in the article, and will not go into details here.

[0153] In some other optional examples, the optical amplifier may further include a second device, wherein the first end of the second device is connected to the output end of the M-th optical amplifier structure, the first end of the second device is connected to the input end of the M+1-th optical amplifier structure, and the third end of the second device is connected to the first device. Alternatively, the first end of the second device is connected to the output end of the N-th optical amplifier structure. Fig.15 Based on the above, the processing method may further include: determining the wavelength band of the complementary light or determining the splitting power of the complementary light.

[0154] It should be understood that the second device can refer to the aforementioned Figure 5a The above contents have been understood and will not be elaborated here.

[0155] In addition, in the above Figure 5a-Figure 5b Based on the structure of the optical amplifier described above, a variety of different devices can be used to perform the function performed by the second device in the optical amplifier. For example, a splitter or a coupler can be used to perform the function performed by the second device. Fig.15 Based on the optional examples shown, the processing method may also include the following scenarios for different situations:

[0156] (1) In the case where the second device includes a first wavelength splitter, the processing method may further include: separating the wavelength band of the signal light and the wavelength band of the complementary light to determine the wavelength band of the complementary light; or generating a filter spectrum line and obtaining a spontaneous emission ASE spectrum line modulated by the N-stage optical amplification structure, and determining the wavelength of the complementary light based on the filter spectrum line and the spontaneous emission ASE spectrum line. For details, please refer to the aforementioned Figure 6a The optical amplifier described above can be understood for reference only and will not be described in detail here.

[0157] (2) In the case where the second device includes a coupler, the processing method may further include: determining the splitting power of the signal light and the complementary light. Figure 6b The optical amplifier described above can be understood for reference only and will not be described in detail here.

[0158] It should be noted that in the above situation (2), since the signal light and complementary light output by the Nth-stage optical amplifier structure are mixed together, the detection of the optical amplifier output power of the signal light should be the detection of the independent signal light. Therefore, in other examples, the processing method may also include: filtering the complementary light before obtaining the optical amplifier output power of the signal light at the current moment. In this way, by separating the signal light from the complementary light, it is ensured that an independent signal light is obtained, and then it is ensured that the accurate optical amplifier output power of the signal light can be detected later, thereby ensuring that no error occurs during the closed-loop adjustment process.

[0159] In addition, in the above Figure 6a-6b Based on the structure of the optical amplifier described above, a variety of different devices can also be used to perform the function performed by the first device in the optical amplifier. For example, an adjustable optical attenuator and a filter can be used to perform the function performed by the first device. Fig.15 Based on the optional examples shown, the processing method may also include the following scenarios for different situations:

[0160] (1) In the case where the first device includes a first adjustable optical attenuator and a first filter, the processing method may further include: selecting a lasing wavelength from the wavelength band of the complementary light, so as to lasing the complementary light at the lasing wavelength after adjusting the loop attenuation.

[0161] In this example, the output signal light and complementary light are mixed together. Therefore, after the mixed signal light and complementary light are processed, the wavelength band of the signal light and the wavelength band of the complementary light can be separated to obtain the wavelength band of the complementary light. Further, any lasing wavelength is selected from the wavelength band of the complementary light, and after adjusting the loop attenuation, the complementary light is lasered according to the lasing wavelength, so that the complementary light can release or consume the pumping energy of each level of optical amplification structure under the enablement of the second pumping current value. Not only can the gain of the signal light be accurately controlled in real time to maintain the stability of the gain, but also the phenomenon of transient overshoot of the optical amplification generated by the signal light in each level of optical amplification structure can be eliminated. For details, please refer to the aforementioned Figure 8a The optical amplifier described above can be understood for reference only and will not be described in detail here.

[0162] (2) In the case where the first device includes a second adjustable optical attenuator, the processing method may further include: after adjusting the loop attenuation, lasing the complementary light according to the wavelength of the complementary light.

[0163] In this example, when the first filter is not included in the first device, in order to be able to laser the complementary light after adjusting the loop attenuation, the complementary light can be lasered at the wavelength of the complementary light after the spontaneous emission ASE spectrum line and the filter spectrum line are used to directly determine the wavelength of the complementary light. There is no need to select a suitable laser wavelength from the wavelength band of the complementary light again, which is more efficient. For details, please refer to the aforementioned Figure 8b The optical amplifier described above can be understood for reference only and will not be described in detail here.

[0164] (3) In the case where the first device includes a third adjustable optical attenuator and a second filter, the processing method may further include: determining the optical power of the complementary light from the split power of the signal light and the complementary light for adjusting the loop attenuation size, and then lasing the complementary light according to the optical power of the complementary light.

[0165] In this example, since the output signal light and complementary light are mixed together, and the mixed signal light and complementary light may not be able to filter out the wavelength band of the complementary light after processing, but can only determine the split power of the mixed signal light and complementary light. Therefore, the optical power of the complementary light can also be filtered out from the split power of the signal light and the complementary light. And after adjusting the attenuation of the loop, the complementary light is lasered according to the optical power of the complementary light, so that the complementary light can release or consume the pumping energy of each level of optical amplification structure under the enablement of the second pump current value. Not only can the gain of the signal light be accurately controlled in real time to maintain the stability of the gain, but also the phenomenon of transient overshoot of the optical amplification generated by the signal light in each level of optical amplification structure can be eliminated. For details, please refer to the aforementioned Figure 8c-Figure 8d The optical amplifier described above can be understood for reference only and will not be described in detail here.

[0166] In some optional examples, the processing method may further include: detecting the optical amplifier input power of the signal light at a current moment.

[0167] In some optional examples, the processing method may further include: detecting the optical amplifier output power of the signal light at a current moment.

[0168] In summary, Fig.15 and Fig.15 The processing method described in the corresponding optional example is mainly applied to the aforementioned Figure 2a-Figure 11 The optical amplifier provided in the embodiment of the present invention can also be referred to the aforementioned Figure 2a-Figure 11 The contents of the optical amplifier described in the figure should be understood as such and will not be elaborated here.

[0169] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0170] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical amplifier, It is characterized in that The optical amplifier comprises an optical amplifier controller, a combiner, a first device, and N-stage optical amplifier structures arranged in a cascade manner; the optical amplifier controller is connected to the first device and to each stage of the optical amplifier structures in the N-stage optical amplifier structures; the combiner is connected to the input end of the first stage optical amplifier structure, or is connected between the output end of the K-th stage optical amplifier structure and the input end of the K+1-th stage optical amplifier structure; the first end of the first device is connected to the combiner; the second end of the first device is connected to the output end of the N-th stage optical amplifier structure, or is connected between the output end of the M-th stage optical amplifier structure and the input end of the M+1-th stage optical amplifier structure; N≥2, 1≤K≤M, 2≤M≤N, and N, M, and K are integers; The N-stage optical amplification structure is used to amplify signal light; The optical amplifier controller is used for: Acquire a first gain value of the signal light; Determine, according to the first gain value and the association relationship, a first adjustable optical attenuator VOA value and a first pump current value corresponding to the first gain value, wherein the association relationship is a relationship among the first gain value, the first VOA value and the first pump current value, the first VOA value reflects the loop attenuation of the first device, and the first pump current value reflects the pump current required by each level of the optical amplification structure in the N-level optical amplification structure; sending the first VOA value to the first device; The first device is used to adjust the loop attenuation according to the first VOA value to emit complementary light corresponding to the signal light.

2. The optical amplifier according to claim 1, It is characterized in that The optical amplifier controller is further used for: Acquire a second gain value of the signal light, and a second VOA value and a second pump current value corresponding to the second gain value; When the first gain value is not equal to the second gain value, the first gain value is updated to the second gain value, the first VOA value is updated to the second VOA value, and the first pump current value is updated to the second pump current value.

3. The optical amplifier according to claim 2, It is characterized in that The optical amplifier controller is further used for: Obtaining the optical amplifier input power of the signal light at a current moment and the optical amplifier input power at a previous moment; Determine the change of the OA input power according to the OA input power at the current moment and the OA input power at the previous moment; When the optical amplifier input power change magnitude is greater than an open-loop threshold, controlling the pump power of each level of the optical amplifier structure according to the pump current value corresponding to the second gain value, and sending the second VOA value to the first device; The first device is further used for: The loop attenuation is adjusted according to the second VOA value.

4. The optical amplifier according to claim 3, It is characterized in that The optical amplifier controller is also used for: Obtaining the optical amplifier output power of the signal light at the current moment; Calculating the actual gain value of the signal light based on the optical amplifier input power and the optical amplifier output power at the current moment; Calculating a gain difference value between the actual gain value and the second gain value; When the gain difference value is greater than or equal to a closed-loop threshold, adjusting a third pump current value corresponding to the actual gain value according to the gain difference value to control the pump power of each level of optical amplification structure, and adjusting a third VOA value corresponding to the actual gain value according to the gain difference value, wherein the closed-loop threshold value is less than the open-loop threshold value; The first device is further used for: The loop attenuation is adjusted according to the third VOA value.

5. The optical amplifier according to any one of claims 1 to 4, It is characterized in that The optical amplifier further comprises a second device, wherein a first end of the second device is connected to an output end of the M-th optical amplification structure, a second end of the second device is connected to an input end of the M+1-th optical amplification structure, and a third end of the second device is connected to the first device; or, a first end of the second device is connected to an output end of the N-th optical amplification structure; The second device is used to determine the wavelength band of the complementary light, or determine the split power of the complementary light.

6. The optical amplifier according to claim 5, It is characterized in that The second device includes a first wave splitter; The first wave splitter is used to separate the wavelength band of the signal light and the wavelength band of the complementary light to determine the wavelength band of the complementary light; or, The first splitter is used to generate a filter spectrum line and obtain a spontaneous emission ASE spectrum line modulated by the N-stage optical amplification structure, and determine the wavelength of the complementary light based on the filter spectrum line and the spontaneous emission ASE spectrum line.

7. The optical amplifier according to claim 5, It is characterized in that The second device includes a coupler; The coupler is used to determine the splitting power of the signal light and the complementary light.

8. The optical amplifier according to claim 6, It is characterized in that The first device includes a first adjustable optical attenuator and a first filter; The first filter is used to select a lasing wavelength from the wavelength band of the complementary light, so as to lasing the complementary light at the lasing wavelength after the first adjustable optical attenuator adjusts the loop attenuation.

9. The optical amplifier according to claim 6, It is characterized in that The first device includes a second adjustable optical attenuator; The second adjustable optical attenuator is used to laser the complementary light according to the wavelength of the complementary light after adjusting the loop attenuation.

10. The optical amplifier according to claim 7, It is characterized in that The first device includes a third adjustable optical attenuator and a second filter; The second filter is used to determine the optical power of the complementary light from the split power of the signal light and the complementary light, so as to laser the complementary light according to the optical power of the complementary light after the third adjustable optical attenuator adjusts the loop attenuation.

11. The optical amplifier according to claim 10, It is characterized in that The optical amplifier further comprises a third filter and an optical amplifier output end, wherein a first end of the third filter is connected to the optical amplifier output end, and a second end of the third filter is connected to the optical amplifier controller; The third filter is used to filter the complementary light before the optical amplifier controller obtains the optical amplifier output power of the signal light at the current moment.

12. The optical amplifier according to any one of claims 3 to 4, It is characterized in that The optical amplifier further comprises an input end detector, a first end of the input end detector is connected to the input end of the first stage optical amplifier structure, and a second end of the input end detector is connected to the optical amplifier controller; The input end detector is used to detect the optical amplifier input power of the signal light at a current moment, and send the optical amplifier input power at the current moment to the optical amplifier controller.

13. The optical amplifier according to claim 5, It is characterized in that The optical amplifier further comprises an output end detector, a first end of the output end detector is connected to the output end of the Nth stage optical amplifier structure or the second device, and a second end of the output end detector is connected to the optical amplifier controller; The output end detector is used to detect the optical amplifier output power of the signal light at a current moment, and send the optical amplifier output power at a current moment to the optical amplifier controller.

14. The optical amplifier according to any one of claims 1 to 4, It is characterized in that The optical amplifier further comprises an optical amplifier input end, and the optical amplifier input end is connected to the input end of the first-stage optical amplifier structure.

15. An optical communication system, It is characterized in that The optical communication system comprises an optical transmitter and at least one optical amplifier according to any one of claims 1 to 14, wherein the optical transmitter is used to generate signal light.

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