Method for adjusting gain flatness of amplifier, and amplifier

Abstract

Embodiments of the present disclosure provide a method for adjusting gain flatness of an amplifier, and an amplifier. The method comprises: calculating a target output power of pump light in a preset mode and a target output power ratio relationship of the pump light in the preset mode; and on the basis of the target output power of the pump light and the target output power ratio relationship of the pump light, by means of a pump light generating device, adjusting a current power output ratio of the pump light in the preset mode, so as to achieve a target gain flatness. Thus, the output power ratio relationship is adjusted by means of the pump light generating device, so as to dynamically adjust the gain flatness of the amplifier, thereby solving the problem in the related art that the gain flatness cannot be changed at any time on the basis of a current system state, and thus more effectively controlling inter-mode and inter-core gain differences at a desired level.

Description

Amplifier gain flatness adjustment method and amplifier

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure is based on Chinese patent application CN202311191977.1, filed on September 13, 2023, entitled “Amplifier Gain Flatness Adjustment Method and Amplifier,” and claims the priority of that patent application, all of the contents disclosed therein are incorporated into this disclosure by reference. Technical Field

[0003] The embodiments of the present disclosure relate to the field of communications, and in particular, to a method for adjusting amplifier gain flatness and an amplifier. Background Art

[0004] In recent years, space-division multiplexing transmission methods based on few-mode fiber or multi-core fiber have been proposed, that is, using multiple cores or multiple modes in the same optical fiber to effectively improve the optical fiber transmission capacity. The combination of the two can achieve an order of magnitude increase in optical fiber capacity.

[0005] However, it is well known that signals in different cores or modes within an optical fiber exhibit different performance differences during photon excitation. This means that the signal amplification process produces different gains for signals in different cores and modes within the same optical fiber. The difference in gain between different modes and cores after amplification is called the inter-mode gain difference or inter-core gain difference. The existence of inter-mode gain difference and inter-core gain difference can significantly affect the transmission capacity of the system.

[0006] To address inter-mode and inter-core gain differences in space-division multiplexing (SDM), various solutions have been proposed. These include fiber doping techniques and fiber structure designs that achieve low inter-mode and inter-core gain differences. However, these solutions can only suppress inter-mode and inter-core gain differences to a certain extent and can only maintain low inter-mode or inter-core gain differences within specific SDM systems and service conditions. Gain flatness cannot be adjusted based on the current system state.

[0007] Summary of the Invention

[0008] The embodiments of the present disclosure provide a method for adjusting amplifier gain flatness and an amplifier, so as to at least solve the problem of inter-mode or inter-core gain difference during signal optical power amplification in an existing space division multiplexing system.

[0009] According to one embodiment of the present disclosure, a method for adjusting gain flatness of an amplifier is provided, wherein the amplifier includes a pump light generating device, including:

[0010] Calculating a target output power of the preset mode pump light and a target output power ratio of the preset mode pump light;

[0011] According to the relationship between the target output power of the pump light and the target output power ratio of the pump light, the current power output ratio of the pump light in the preset mode is adjusted by the pump light generating device to achieve the target gain flatness.

[0012] According to another embodiment of the present disclosure, there is provided an amplifier, comprising:

[0013] A pump light generating device for adjusting the power output ratio of the pump light in a preset mode;

[0014] The controller is configured to calculate a target output power ratio relationship between the pump light of the preset mode and the pump light of the preset mode; and control the pump light generating device to adjust a current power output ratio of the pump light of the preset mode according to the target output power of the pump light and the pump light target output power ratio relationship to achieve the target gain flatness. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG1 is a flow chart of a method for adjusting amplifier gain flatness according to an embodiment of the present disclosure;

[0016] FIG2 is a structural block diagram of an amplifier according to an embodiment of the present disclosure;

[0017] FIG3 is a schematic structural diagram of a few-mode amplifier according to an embodiment of the present disclosure;

[0018] FIG4 is a structural diagram of a pump light generating device according to an embodiment of the present disclosure;

[0019] FIG5 is a diagram of a two-stage power coupling ratio controlled cascade pump light generating device according to an embodiment of the present disclosure;

[0020] FIG6 is a schematic structural diagram of a power coupling ratio controller according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings and in conjunction with embodiments.

[0022] In this embodiment, a method for adjusting the gain flatness of an amplifier is provided. FIG1 is a flow chart of the method for adjusting the gain flatness of an amplifier according to an embodiment of the present disclosure. As shown in FIG1 , the flow chart includes the following steps:

[0023] Step S101 : calculating a target output power of a preset mode pump light and a target output power ratio of the preset mode pump light.

[0024] The pump light of the embodiment of the present disclosure may be generated by a pump light generating device with an adjustable mode power ratio.

[0025] For example, the pump light generated by the pump light generating device may have multiple modes. The power ratios of the different modes can be controlled by a controller. The impact of the power ratios of the different pump light modes on the different signal light modes and the fiber core gain is calibrated before achieving the aforementioned gain flattening. Therefore, the aforementioned calculation of the power ratios of the different pump light modes can be calculated using pre-calibrated data.

[0026] In an exemplary embodiment, the calculating the target output power of the preset mode pump light and the target output power ratio relationship of the preset mode pump light includes: calculating the target output power of the preset mode pump light and the target output power ratio relationship of the preset mode pump light based on the preset signal light mode, the preset signal light target power gain, and the preset target gain flatness of the amplifier.

[0027] Step S102 : According to the relationship between the target output power of the pump light and the target output power ratio of the pump light, the pump light generating device adjusts the current power output ratio of the pump light in the preset mode to achieve the target gain flatness.

[0028] For example, after calculating the target output power of the preset mode pump light and the target output power ratio relationship of the preset mode pump light, the output power of the current preset mode pump light can be adjusted by the pump light generating device so that the output power of the current preset mode pump light satisfies the target output power ratio relationship, thereby achieving the target gain flatness.

[0029] In an exemplary embodiment, after adjusting, by the pump light generating device, the current power output ratio of the pump light in the preset mode according to the target output power of the pump light and the target pump light output power ratio, the method further includes:

[0030] monitoring a current gain flatness of the signal light;

[0031] If the current gain flatness of the signal light does not reach the target gain flatness, calculating the power output ratio of the pump light in the preset mode based on the power gain corresponding to the current gain flatness, the preset mode of the pump light, and the target gain flatness between the signal light, and adjusting the current power output ratio of the pump light in the preset mode by a pump light generating device based on the recalculated power output ratio of the pump light in the preset mode;

[0032] When the current gain flatness of the signal light reaches the target gain flatness, the adjustment of the current power output ratio of the pump light in the preset mode is stopped.

[0033] For example, during the process of the pump light generating apparatus adjusting the current power output ratio of the pump light in the preset mode, the current gain flatness of the signal light may be monitored.

[0034] If the current gain flatness of the signal light does not reach the target gain flatness, the power output ratio of the pump light in the preset mode can be calculated based on the power gain corresponding to the current gain flatness, the preset mode of the pump light, and the target gain flatness between the signal light and the pump light. Based on the recalculated power output ratio of the pump light in the preset mode, the current power output ratio of the pump light in the preset mode can be adjusted by the pump light generating device.

[0035] If the current gain flatness of the signal light reaches the target gain flatness, the adjustment of the current power output ratio of the pump light in the preset mode may be stopped.

[0036] In the disclosed embodiments, a target output power of pump light in a preset mode and a target output power ratio of pump light in the preset mode are calculated. Based on the target output power of the pump light and the target output power ratio of the pump light, a pump light generating device adjusts the current power output ratio of the pump light in the preset mode to achieve target gain flatness. Thus, the pump light generating device adjusts the output power ratio to achieve dynamic adjustment of the gain flatness of the amplifier. This solves the problem in related arts where gain flatness cannot be changed at any time based on the current system state, and can more effectively control the gain differences between modes and between cores to the required levels.

[0037] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus the necessary general hardware platform, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present disclosure is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), including a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present disclosure.

[0038] In this embodiment, an amplifier is also provided. The device is used to implement the above embodiments and preferred implementations, and details that have been explained will not be repeated here.

[0039] FIG2 is a block diagram of an amplifier according to an embodiment of the present disclosure. As shown in FIG2 , the amplifier includes:

[0040] A pump light generating device 201, configured to adjust the power output ratio of the pump light in a preset mode;

[0041] The controller 202 is configured to calculate a target output power ratio of the pump light in the preset mode and a target output power ratio of the pump light in the preset mode; and control the pump light generating device 201 to adjust a current power output ratio of the pump light in the preset mode according to the target output power of the pump light and the target output power ratio of the pump light to achieve the target gain flatness.

[0042] In an exemplary embodiment, the controller 202 is configured to calculate a target output power of the preset mode pump light and a target output power ratio of the preset mode pump light based on a preset signal light mode, a preset signal light target power gain, and a preset target gain flatness of the amplifier.

[0043] In an exemplary embodiment, the controller is further configured to monitor the current gain flatness of the signal light after adjusting the current power output ratio of the pump light in the preset mode through the pump light generating device according to the relationship between the target output power of the pump light and the target output power ratio of the pump light; calculate the power output ratio of the pump light in the preset mode based on the power gain corresponding to the current gain flatness, the preset mode of the pump light, and the target gain flatness between the signal light, and adjust the current power output ratio of the pump light in the preset mode based on the recalculated power output ratio of the pump light in the preset mode; and stop adjusting the current power output ratio of the pump light in the preset mode when the current gain flatness of the signal light reaches the target gain flatness.

[0044] The following is a further explanation of the above amplifier through an example:

[0045] Example 1:

[0046] FIG3 is a schematic structural diagram of a few-mode amplifier according to an embodiment of the present disclosure. As shown in FIG3 , the few-mode amplifier includes a few-mode fiber 301, an erbium-doped fiber 302, a pump light generating device 303, an optical coupler 304, an optical isolator 305, and an optical monitor 306, wherein 301-1 and 301-2 are both few-mode fibers.

[0047] Few-mode fiber 301-1 is used for signal light input, few-mode fiber 301-2 is used for amplified signal light output, erbium-doped fiber 302 is used to perform a photon excitation process to amplify the signal light, pump light generator 303 is used to generate pump light, optical coupler 304 is used to couple the signal light and pump light, optical isolator 305 is used to filter out residual pump light, and optical monitor 306 is used to detect the amplification status of the signal light. Signal light is input from few-mode fiber 301-1. The input signal light and the pump light generated by the pump light generator 303 are coupled at optical coupler 304. The coupled and combined light can be input into erbium-doped fiber 302 for amplification through photon excitation.

[0048] Since the light output from the erbium-doped fiber 302 includes both amplified signal light and residual pump light, the light output from the erbium-doped fiber 302 is filtered by the optical isolator 305 to retain only the amplified signal light, which is then input into the few-mode fiber 301-2. Finally, the few-mode fiber 301-2 outputs the amplified signal light to the next-level device.

[0049] In order to ensure the effectiveness of the signal light amplification process, an optical monitor 306 may be provided in the erbium-doped optical fiber 302 for monitoring the amplified signal light.

[0050] The following describes the pump light generating device in the amplifier:

[0051] Figure 4 is a structural diagram of a pump light generating device according to an embodiment of the present disclosure. As shown in Figure 4, the pump light generating device includes: a pump laser 401, which is used to generate original pump light of the pump light generating device and send the original pump light to a mode selection converter 402; the output end of the mode selection converter 402 is connected to the input end of the few-mode fiber 403, which is used to receive the original pump light, convert the original pump light into pump light of a preset mode, and inject the pump light of the preset mode into the few-mode fiber 403; the power coupling ratio controller 404 is connected to the mode selection converter 402 through the few-mode fiber 403, which is used to receive the pump light of the preset mode and adjust the current output power ratio of the pump light of the preset mode based on the target output power ratio of the pump light of the preset mode.

[0052] For example, the pump laser 401 can emit single-mode (fundamental) 980nm original pump light, which is converted by the mode selective converter 402 into few-mode pump light with two modes, LP01 and LP11, and a power ratio of 1:1. After the few-mode pump light is pumped into the few-mode fiber 403, the power ratio of the two modes can be changed by controlling the power coupler ratio controller 404. The light is then directly pumped into the optical coupler in the amplifier through the few-mode fiber 403 for power amplification.

[0053] As an example, to achieve intermodal gain flatness in the amplifier, the influence of pump light sources LP01 and LP11 on the amplified signal light of different modes can be measured in advance at different powers and ratios. After determining the amplified signal light mode and target gain, the measured curves can be used to determine the optimal optical power and power ratio of pump light sources LPO1 and LP11.

[0054] As an example, the pump light generator of the present disclosure can be configured according to the calculated power ratio of LP01 and LP11 pump lights, and the inter-mode gain flatness of the signal light can be monitored using a signal light monitor. If the gain flatness has reached the target gain flatness, the amplification process can be maintained, and the inter-mode gain flatness adjustment process can be temporarily stopped. If the gain flatness has not reached the target gain flatness, the power coupling ratio controller in the pump light generator can be controlled to adjust the inter-mode gain flatness until gain flatness is achieved.

[0055] In an exemplary embodiment, there are multiple mode selection converters and multiple power coupling ratio controllers, and each mode selection converter is connected in series with a corresponding power coupling ratio controller to form a group, and then multiple groups are cascaded.

[0056] FIG5 is a two-stage power coupling ratio control cascaded pump light generating device according to an embodiment of the present disclosure. As shown in FIG5 , the two-stage power coupling ratio control cascaded pump light generating device includes: a pump laser 501, three mode selection converters (502-1, 502-2, 502-3), three power coupling ratio controllers (503-1, 503-2, 503-3), two mode multiplexing and demultiplexing devices (504-1, 504-2), and seven sections of few-mode optical fibers (505-1 to 505-7).

[0057] In an exemplary embodiment, the pump light generating device further includes a mode multiplexing and demultiplexing device 504, wherein the output end of the few-mode optical fiber 505 is connected to the mode multiplexing and demultiplexing device 504 through the power coupling ratio controller 503; the power coupling ratio controller 503 is further configured to, when the preset mode pump light is not the pump light of the desired mode, inject the pump light after adjusting the current output power ratio of the preset mode pump light into the mode multiplexing and demultiplexing device through the few-mode optical fiber; the mode multiplexing and demultiplexing device 504 is configured to select and output the pump light of the desired mode from the preset mode pump light after adjusting the current output power ratio of the preset mode pump light.

[0058] In an exemplary embodiment, the mode selection converter 502 is used to convert the single-mode signal into a signal of a preset mode when the pump laser outputs a single-mode signal; and to convert the undesired multi-mode signal into a signal of a preset mode when the pump laser outputs an undesired multi-mode signal.

[0059] In an exemplary embodiment, the power coupling ratio controller 503 is configured to apply pressure to the few-mode optical fiber to change the power output ratio of the desired mode pump light.

[0060] As an example, Figure 6 is a structural schematic diagram of a power coupling ratio controller according to an embodiment of the present disclosure. As shown in Figure 6, the power coupling ratio controller 503 includes: a pressure plate 5031, and the few-mode fiber 505 passes through the pressure plate 5031; a sub-controller 5032, which is used to transfer pressure to the few-mode fiber 505 by applying pressure to the pressure plate 5031, so as to change the power output ratio of the desired mode pump light in the few-mode fiber 505.

[0061] In an exemplary embodiment, the sub-controller 5032 determines the pressure value to be applied based on the power output ratio of the preset mode, the mapping relationship between the lateral pressure and the power output ratio of the preset mode, and applies pressure to the pressure plate 5031 according to the pressure value.

[0062] In an exemplary embodiment, the sub-controller 5032 is further used to measure the power output ratio of different modes in the few-mode optical fiber 505 under different lateral pressures of the pressure plate 5031 before applying pressure to the pressure plate 5031, and determine the mapping relationship between the lateral pressure and the power output ratio of the different modes based on the different lateral pressures and the power output ratios of the different modes.

[0063] As an example, after determining the power output ratio relationship of different modes that need to be set, the sub-controller 5032 can calculate the pressure value that needs to be applied and apply pressure to the pressure plate 5031 according to the pressure value.

[0064] As an example, since the few-mode fiber 505 passes through the pressure plate 5031, the pressure exerted on the pressure plate 5031 can be transmitted to the outer surface of the few-mode fiber 505, causing lateral deviation of the fiber. Before implementing pressure control of the pressure plate, the power output ratios of different modes in the few-mode fiber 505 under different lateral pressures of the pressure plate 5031 can be measured in advance. Based on the different lateral pressures and the power output ratios of different modes, a mapping relationship between the lateral pressure and the power output ratios of the different modes can be determined.

[0065] In an exemplary embodiment, the pressure plate 5031 is made of hard acrylic plate, and the sub-controller 5032 is made of a micro axial precession motor.

[0066] As an example, during the implementation of the power coupling ratio controller 503, the pressure plate 5031 can be implemented using a hard acrylic plate, and the sub-controller 5032 can be implemented using a miniature axial precession motor, which can reduce the cost of the pump light generating device and thus reduce the implementation cost of the amplifier. At the same time, the amplifier can be equipped with gain flatness control capability and can dynamically control inter-mode gain balance.

[0067] The disclosed embodiments utilize a power coupling ratio controller within a pump light generator to adjust the power coupling ratio of pump light in different optical modes within an optical fiber. The pump light generator is then applied to an amplifier to achieve the desired relationship between the pump light power injected into a multi-core or few-mode optical fiber, thereby controlling the amplifier's inter-mode gain difference. This eliminates the need for multiple power-adjustable pump lasers, reducing the amplifier's implementation cost.

[0068] The present embodiment provides an implementation method for implementing a few-mode amplification process in an amplifier. The disclosed amplifier gain flatness adjustment method and amplifier can also be applied to a multi-core amplification process. The specific implementation process is referenced to the above-mentioned few-mode amplification process and will not be further described in this embodiment.

[0069] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations of the present disclosure are possible. Any modifications, equivalent substitutions, or improvements made within the principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A method for adjusting gain flatness of an amplifier, wherein the amplifier includes a pump light generating device, comprising: Calculating a target output power of the preset mode pump light and a ratio relationship of the target output power of the preset mode pump light; According to the relationship between the target output power of the pump light and the target output power ratio of the pump light, the current power output ratio of the pump light in the preset mode is adjusted by the pump light generating device to achieve the target gain flatness.

2. The method according to claim 1, wherein: The calculating the target output power of the preset mode pump light and the ratio of the target output power of the preset mode pump light comprises: Based on the preset signal light mode, the preset signal light target power gain and the preset target gain flatness of the amplifier, the target output power of the preset mode pump light and the target output power ratio relationship of the preset mode pump light are calculated.

3. The method according to claim 2, wherein: After adjusting the current power output ratio of the pump light in the preset mode by the pump light generating device according to the target output power of the pump light and the relationship between the target output power ratio of the pump light, the method further includes: monitoring a current gain flatness of the signal light; When the current gain flatness of the signal light does not reach the target gain flatness, the power output ratio of the pump light in the preset mode is calculated based on the power gain corresponding to the current gain flatness, the preset mode of the pump light, and the target gain flatness between the signal light, and based on the recalculated power output ratio of the pump light in the preset mode, the current power output ratio of the pump light in the preset mode is adjusted by a pump light generating device; When the current gain flatness of the signal light reaches the target gain flatness, the current power output ratio of the pump light in the preset mode is stopped from being adjusted.

4. An amplifier, comprising: A pump light generating device, used for adjusting the power output ratio of the pump light in a preset mode; The controller is used to calculate the target output power of the preset mode pump light and the target output power ratio relationship of the preset mode pump light; according to the target output power of the pump light and the target output power ratio relationship of the pump light, control the pump light generating device to adjust the current power output ratio of the pump light of the preset mode to achieve the target gain flatness.

5. The amplifier according to claim 4, wherein The controller is used to calculate the target output power of the preset mode pump light and the target output power ratio relationship of the preset mode pump light based on the preset signal light mode, the preset signal light target power gain and the preset target gain flatness of the amplifier.

6. The amplifier according to claim 5, wherein The controller is further configured to monitor the current gain flatness of the signal light after adjusting the current power output ratio of the pump light in the preset mode through the pump light generating device according to the target output power of the pump light and the target output power ratio of the pump light; calculate the power output ratio of the pump light in the preset mode based on the power gain corresponding to the current gain flatness, the preset mode of the pump light, and the target gain flatness between the signal light, and adjust the current power output ratio of the pump light in the preset mode based on the recalculated power output ratio of the pump light in the preset mode; and stop adjusting the current power output ratio of the pump light in the preset mode when the current gain flatness of the signal light reaches the target gain flatness.

7. The amplifier according to claim 6, wherein The pump light generating device comprises: A pump laser is used to generate the original pump light of the pump light generating device and send the original pump light to Mode selection converter; The output end of the mode selection converter is connected to the input end of the few-mode optical fiber, and is used to receive the original pump light, convert the original pump light into the pump light of the preset mode, and inject the pump light of the preset mode into the few-mode optical fiber; The power coupling ratio controller is connected to the mode selection converter through the few-mode optical fiber, and is used to receive the pump light of the preset mode and adjust the current output power ratio of the pump light of the preset mode based on the target output power ratio of the pump light of the preset mode.

8. The amplifier according to claim 7, wherein The pump light generating device further comprises a mode multiplexing demultiplexer, wherein: The output end of the few-mode optical fiber is connected to the mode multiplexing and demultiplexing device through the power coupling ratio controller; The power coupling ratio controller is further used for injecting the pump light after adjusting the current output power ratio of the preset mode pump light into the mode multiplexing demultiplexer through the few-mode optical fiber when the preset mode pump light is not the pump light of the required mode; The mode multiplexing and demultiplexing device is used to select and output the pump light of the required mode from the pump light of the preset mode after adjusting the current output power ratio of the pump light of the preset mode.

9. The amplifier according to claim 7, wherein: The mode selection converter is used to convert the single-mode signal into a signal of a preset mode when the pump laser outputs a single-mode signal; and to convert the unnecessary multi-mode signal into a signal of a preset mode when the pump laser outputs an unnecessary multi-mode signal.

10. The amplifier according to claim 7, wherein: There are multiple mode selection converters and multiple power coupling ratio controllers. Each mode selection converter is connected in series with a corresponding power coupling ratio controller to form a group, and then multiple groups are cascaded.

11. The amplifier according to claim 7, wherein: The power coupling ratio controller is used to apply pressure to the few-mode optical fiber to change the power output ratio of the required mode pump light.

12. The amplifier according to claim 11, wherein The power coupling ratio controller comprises: a pressure plate through which the few-mode optical fiber passes; A sub-controller is used for applying pressure to the pressure plate to transmit pressure to the few-mode optical fiber, so as to change the power output ratio of the desired mode pump light in the few-mode optical fiber.

13. The amplifier according to claim 12, wherein The sub-controller determines the pressure value to be applied according to the power output ratio of the preset mode, the mapping relationship between the lateral pressure and the power output ratio of the preset mode, and applies pressure to the pressure plate according to the pressure value.

14. The amplifier according to claim 13, wherein The sub-controller is also used to measure the power output ratio of different modes in the few-mode optical fiber under different lateral pressures of the pressure plate before applying pressure to the pressure plate, and determine the mapping relationship between the lateral pressure and the power output ratio of the different modes based on the different lateral pressures and the power output ratios of the different modes.

15. The amplifier according to claim 12, wherein The material of the pressure plate is a hard acrylic plate, and the sub-controller is a micro axial precession motor.

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