Amplifier gain flatness adjusting method and amplifier

Abstract

The embodiment of the invention provides an amplifier gain flatness adjusting method and an amplifier, and the method comprises the steps: calculating the ratio relation between the target output power of preset-mode pump light and the target output power of the preset-mode pump light, and adjusting the gain flatness of the preset-mode pump light according to the ratio relation between the target output power of the pump light and the target output power of the pump light, the current power output ratio of the pump light in the preset mode is adjusted through the pump light generating device to achieve the target gain flatness, so that the output power ratio relation is adjusted through the pump light generating device, and the gain flatness of the amplifier is dynamically adjusted. The problem that the gain flatness cannot be changed at any time according to the current system state in the prior art is solved, and the inter-mode and inter-core gain difference can be more effectively controlled at the required level.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of communications, and in particular to a method for adjusting amplifier gain flatness and an amplifier. Background Art

[0002] In recent years, a space-division multiplexing transmission method based on few-mode fiber or multi-core fiber has 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.

[0003] However, it is well known that signals in different cores or different modes in optical fibers will show different differences during the photon excitation process, which means that the signal amplification process will produce different gains for signals in different cores and different modes in the same optical fiber. The difference between the different gains generated between different cores in different modes after the signal is amplified is called the inter-mode gain difference or the inter-core gain difference. The existence of the inter-mode gain difference and the inter-core gain difference will greatly affect the transmission capacity of the system.

[0004] In order to solve the inter-mode gain difference and inter-core gain difference in space division multiplexing, related technologies have proposed many solutions, including the use of fiber doping technology and fiber structure design that can achieve low inter-mode and inter-core gain differences. However, these solutions can only suppress the inter-mode and inter-core gain differences to a certain extent, and can only maintain low mode or inter-core gain differences under specific space division multiplexing systems and service conditions. Gain flatness cannot be changed at any time according to the current system status. Summary of the invention

[0005] The embodiment of the present invention provides 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 when amplifying signal optical power in an existing space division multiplexing system.

[0006] According to an embodiment of the present invention, a method for adjusting gain flatness of an amplifier is provided, wherein the amplifier includes a pump light generating device, including:

[0007] 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;

[0008] 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.

[0009] According to another embodiment of the present invention, there is provided an amplifier, comprising:

[0010] A pump light generating device, used for adjusting the power output ratio of the pump light in a preset mode;

[0011] 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.

[0012] In the embodiment of the present invention, a target output power ratio relationship of a preset mode pump light and a target output power ratio relationship of the preset mode pump light are calculated, and according to the target output power of the pump light and the target output power ratio relationship of the pump light, a pump light generating device is used to adjust the current power output ratio of the preset mode pump light to achieve a target gain flatness, thereby adjusting the output power ratio relationship through the pump light generating device to achieve dynamic adjustment of the gain flatness of the amplifier, thereby solving the problem in the related art that the gain flatness cannot be changed at any time according to the current system state, and the gain difference between modes and between cores can be more effectively controlled at a required level. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a flow chart of a method for adjusting amplifier gain flatness according to an embodiment of the present invention;

[0014] Figure 2 is a structural block diagram of an amplifier according to an embodiment of the present invention;

[0015] Figure 3 is a structural schematic diagram of a few-mode amplifier according to an embodiment of the present invention;

[0016] Figure 4 is a structural diagram of a pump light generating device according to an embodiment of the present invention;

[0017] Figure 5 A two-stage power coupling ratio controlled cascade pump light generating device according to an embodiment of the present invention;

[0018] Figure 6 4 is a schematic diagram of the structure of a power coupling ratio controller according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and in combination with the embodiments.

[0020] In this embodiment, a method for adjusting the gain flatness of an amplifier is provided. Figure 1 is a flow chart of a method for adjusting amplifier gain flatness according to an embodiment of the present invention. Figure 1As shown, the process includes the following steps:

[0021] Step S101 , calculating a target output power of a preset mode pump light and a ratio relationship between a target output power of a preset mode pump light.

[0022] The pump light of the embodiment of the present invention may be generated by a pump light generating device with adjustable mode power ratio.

[0023] Exemplarily, the pump light emitted by the pump light generating device may have multiple modes. The power ratio relationship of different modes may be controlled by a controller. The influence of the power ratio relationship of different modes of the pump light on different modes of the signal light and the core gain is calibrated before achieving the above-mentioned gain flattening. Therefore, the above-mentioned calculation of the power ratio relationship of different modes of the pump light may be calculated by pre-calibrated data.

[0024] In an exemplary embodiment, the calculating of the target output power of the preset mode pump light and the target output power ratio of the preset mode pump light includes: calculating the target output power of the preset mode pump light and the target output power ratio 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.

[0025] Step S102 : adjusting the current power output ratio of the pump light in the preset mode by 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, so as to achieve the target gain flatness.

[0026] Exemplarily, 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.

[0027] In an exemplary embodiment, 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 pump light target output power ratio relationship, the method further includes:

[0028] monitoring a current gain flatness of the signal light;

[0029] 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;

[0030] 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.

[0031] Exemplarily, during the process in which the pump light generating device adjusts the current power output ratio of the pump light in the preset mode, the current gain flatness of the signal light may be monitored.

[0032] If the current gain flatness of the signal light does not reach the target gain flatness, the power output ratio of the preset mode pump light can be calculated according to the power gain corresponding to the current gain flatness, the preset mode of the pump light, and the target gain flatness between the signal lights. According to the recalculated power output ratio of the preset mode pump light, the current power output ratio of the preset mode pump light can be adjusted by the pump light generating device.

[0033] If 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 may be stopped from being adjusted.

[0034] In the embodiment of the present invention, a target output power ratio relationship of a preset mode pump light and a target output power ratio relationship of the preset mode pump light are calculated, and according to the target output power of the pump light and the target output power ratio relationship of the pump light, a pump light generating device is used to adjust the current power output ratio of the preset mode pump light to achieve a target gain flatness, thereby dynamically adjusting the gain flatness of the amplifier by adjusting the output power ratio relationship through the pump light generating device, solving the problem in the related art that the gain flatness cannot be changed at any time according to the current system state, and the gain difference between modes and between cores can be more effectively controlled at a required level.

[0035] 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 a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, 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, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0036] In this embodiment, an amplifier is also provided. The device is used to implement the above embodiments and preferred implementation modes, and those that have been explained will not be repeated here.

[0037] Figure 2 is a block diagram of an amplifier according to an embodiment of the present invention. Figure 2 As shown, the amplifier includes:

[0038] A pump light generating device 201, used to adjust the power output ratio of the pump light in a preset mode;

[0039] The controller 202 is used to calculate the target output power of the preset mode pump light and the target output power ratio of the preset mode pump light; according to the target output power of the pump light and the target output power ratio of the pump light, control the pump light generating device 201 to adjust the current power output ratio of the pump light of the preset mode to achieve the target gain flatness.

[0040] In an exemplary embodiment, the controller 202 is used to calculate the target output power of the preset mode pump light and the target output power ratio 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.

[0041] In an exemplary embodiment, the controller is further used 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; when the current gain flatness of the signal light does not reach the target gain flatness, 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; when the current gain flatness of the signal light reaches the target gain flatness, stop adjusting the current power output ratio of the pump light in the preset mode.

[0042] The following is a further explanation of the above amplifier through an example:

[0043] Example 1:

[0044] Figure 3 is a schematic diagram of the structure of a few-mode amplifier according to an embodiment of the present invention, such as Figure 3 As shown, 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.

[0045] The few-mode fiber 301-1 is used for signal light input, the few-mode fiber 301-2 is used for amplified signal light output, the erbium-doped fiber 302 is used for performing a photon excitation process to amplify the signal light, the pump light generator 303 is used for generating pump light, the optical coupler 304 is used for coupling the signal light and the pump light, the optical isolator 305 is used for filtering out the residual pump light, and the optical monitor 306 is used for detecting the amplification state of the signal light. The signal light is input from the few-mode fiber 301-1, and the input signal light is coupled with the pump light generated by the pump light generator 303 on the optical coupler 304, and the coupled and combined light can be input into the erbium-doped fiber 302 together for amplification through the photon excitation process.

[0046] Since the light output from the erbium-doped fiber 302 includes both the amplified signal light and the 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, and then the retained amplified signal light is input to the few-mode fiber 301-2, and finally the few-mode fiber 301-2 outputs the amplified signal light to the next-level device.

[0047] 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.

[0048] The pump light generating device in the amplifier is described below:

[0049] Figure 4 is a structural diagram of a pump light generating device according to an embodiment of the present invention, such as Figure 4 As shown, 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 a few-mode fiber 403, which is used to receive the original pump light, convert the original pump light into a 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.

[0050] For example, the pump laser 401 can emit a single-mode (fundamental mode) 980nm original pump light, which is converted into a few-mode pump light having two modes, LP01 and LP11, and a power ratio of 1:1 after passing through the mode selection converter 402. After the few-mode pump light is pumped into the few-mode fiber 403, the power ratio of the two modes LP01 and LP11 can be changed by controlling the power coupler ratio controller 404, and then directly pumped into the optical coupler in the amplifier through the few-mode fiber 403 for power amplification.

[0051] As an example, in order to achieve the inter-mode gain flatness of the amplifier, the influence curves of the pump lights LP01 and LP11 on the different mode signal lights to be amplified under different powers and different ratios can be measured in advance. After determining the mode of the signal light to be amplified and the target gain, the reasonable optical power and power ratio relationship of the pump lights LPO1 and LP11 can be determined based on the measured curves.

[0052] As an example, the pump light generating device of the present invention can be set according to the calculated LP01 and LP11 pump light power ratio relationship, and then the inter-mode gain flatness in the signal light can be monitored by the 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 is temporarily stopped; if the gain flatness does not reach the target gain flatness, the power coupling ratio controller in the pump light generating device can be controlled to adjust the inter-mode gain flatness until the gain is flat.

[0053] 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.

[0054] Figure 5 A two-stage power coupling ratio controlled cascade pump light generating device according to an embodiment of the present invention is provided. Figure 5 As shown, a two-stage power coupling ratio control cascade 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 (505-1~505-7).

[0055] In an exemplary embodiment, the pump light generating device further includes a mode multiplexing demultiplexer 504, wherein the output end of the few-mode optical fiber 505 is connected to the mode multiplexing demultiplexer 504 through the power coupling ratio controller 503; the power coupling ratio controller 503 is further used for, when the preset mode pump light is not the pump light of the required mode, 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; the mode multiplexing demultiplexer 504 is used for selecting and outputting the pump light of the required mode from the preset mode pump light after adjusting the current output power ratio of the preset mode pump light.

[0056] 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 output is a single-mode signal; and to convert the unnecessary multi-mode signal into a signal of a preset mode when the pump laser output is an unnecessary multi-mode signal.

[0057] In an exemplary embodiment, the power coupling ratio controller 503 is used to apply pressure to the few-mode optical fiber to change the power output ratio of the desired mode pump light.

[0058] As an example, Figure 6 is a schematic diagram of a power coupling ratio controller according to an embodiment of the present invention. Figure 6As shown, the power coupling ratio controller 503 includes: a pressure plate 5031, through which the few-mode fiber 505 passes; 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.

[0059] In an exemplary embodiment, the sub-controller 5032 determines the pressure value to be applied based on the power output ratio of a 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.

[0060] In an exemplary embodiment, the sub-controller 5032 is also 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.

[0061] 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.

[0062] As an example, since the few-mode optical fiber 505 passes through the pressure plate 5031, the pressure exerted on the pressure plate 5031 can be transmitted to the outer side of the few-mode optical fiber 505, forming a lateral deviation of the optical fiber. Before implementing the pressure control of the pressure plate, the power output ratios of different modes in the few-mode optical fiber 505 under different lateral pressures of the pressure plate 5031 can be measured in advance, and the mapping relationship between the lateral pressure and the power output ratios of different modes can be determined according to different lateral pressures and the power output ratios of different modes.

[0063] In an exemplary embodiment, the pressure plate 5031 is made of hard acrylic plate, and the sub-controller 5032 is made of a miniature axial precession motor.

[0064] As an example, during the implementation of the power coupling ratio controller 503, the pressure plate 5031 can be implemented by a hard acrylic plate, and the sub-controller 5032 can be implemented by a miniature axial precession motor, which can reduce the cost of the pump light generating device, thereby reducing the implementation cost of the amplifier, and at the same time enable the amplifier to have gain flatness control capability and dynamically control inter-mode gain balance.

[0065] The embodiment of the present invention changes the power coupling ratio of different modes of pump light in the optical fiber through the power coupling ratio controller in the pump light generating device, and applies the pump light generating device to the amplifier, thereby obtaining the required power relationship of different modes of pump light injected into the multi-core or few-mode optical fiber, and realizing the control of the amplifier inter-mode gain difference. At the same time, there is no need to configure multiple power-adjustable pump lasers, which reduces the implementation cost of the amplifier.

[0066] The embodiment of the present invention provides an implementation method of an amplifier in the process of realizing few-mode amplification. The amplifier gain flatness adjustment method and the amplifier of the present invention can also be applied to the multi-core amplification process. The specific implementation process refers to the above-mentioned few-mode amplification process, and this embodiment will not be repeated here.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for adjusting amplifier gain flatness, characterized in that: The amplifier comprises 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, characterized in that 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, characterized in that 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, characterized in that: The amplifier comprises: 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, characterized in that 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, characterized in that 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, characterized in that The pump light generating device comprises: A pump laser, used to generate original pump light of the pump light generating device, and send the original pump light to the 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that The material of the pressure plate is hard acrylic plate, and the sub-controller is a micro axial precession motor.

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