A gain-slope-adjustable fiber amplifier and method

Abstract

This invention relates to the field of optical communication technology, and in particular to an adjustable gain slope fiber amplifier and method, comprising: a control unit, a first-stage amplifier, a dispersion compensation unit, and a second-stage amplifier; a first detector is connected to the output of the first-stage amplifier, and a second detector is connected to the input of the second-stage amplifier; the first-stage amplifier includes an adjustable attenuator; the dispersion compensation unit is detected by the first and second detectors, and the insertion loss value of the dispersion compensation unit is obtained by the control unit; simultaneously, the attenuation amount of the adjustable attenuator is obtained by the control unit based on the insertion loss value of the dispersion compensation unit, and the attenuation amount of the adjustable attenuator is adjusted according to the obtained attenuation amount of the adjustable attenuator to ensure that the total insertion loss value of the optical path in the fiber amplifier remains stable, so as to ensure that the gain slope of the fiber amplifier output meets the requirements when the insertion loss value of the dispersion compensation unit changes.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to an adjustable gain slope fiber amplifier and method. Background Technology

[0002] With the development of optical fiber communication technology, the requirements for the performance indicators of traditional erbium-doped fiber amplifiers (EDFAs) are becoming increasingly stringent. In terms of optical performance, gain flatness is a crucial indicator, and it is often linked to gain slope. Furthermore, to meet the application requirements of EDFAs in different scenarios, there are often different requirements for the gain slope. Therefore, controlling the gain flatness and gain slope of EDFAs is extremely important for their application in systems.

[0003] This section focuses on gain slope control, as many factors are related to the EDFA gain slope, such as pump power, erbium fiber parameters and length, erbium fiber temperature, and the attenuation spectrum of the gain flattening filter (GFF). These factors can usually be eliminated by setting the EDFA's operating mode, using a heater to control the erbium fiber temperature, and adding or removing fibers. These methods can typically adjust the gain slope of a conventional EDFA module to meet usage requirements. However, in practical applications, dispersion compensation units are often present. When the insertion loss value of the dispersion compensation unit changes, the gain slope of the EDFA module also changes, thus failing to meet usage requirements.

[0004] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to ensure that the gain slope of the fiber amplifier output meets the requirements when the insertion loss value of the dispersion compensation unit changes.

[0006] The present invention adopts the following technical solution:

[0007] In a first aspect, an adjustable gain slope fiber amplifier is provided, comprising: a control unit, a first-stage amplifier, a dispersion compensation unit, and a second-stage amplifier; the output terminal of the first-stage amplifier is connected to the input terminal of the dispersion compensation unit, and the output terminal of the dispersion compensation unit is connected to the input terminal of the second-stage amplifier.

[0008] A first detector is connected to the output terminal of the first stage amplifier, and a second detector is connected to the input terminal of the second stage amplifier; the first stage amplifier includes an adjustable attenuator, and the control terminal of the adjustable attenuator, the first detector, and the second detector are respectively connected to the control unit;

[0009] The control unit is used to obtain the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the detection results of the second detector.

[0010] The control unit is also used to adjust the attenuation of the adjustable attenuator according to the insertion loss value of the dispersion compensation unit, so as to ensure the stability of the gain slope of the fiber amplifier output.

[0011] Preferably, a third detector is connected to the input terminal of the adjustable attenuator, and a fourth detector is connected to the output terminal of the adjustable attenuator.

[0012] The third and fourth detectors are respectively connected to the control unit, and the third and fourth detectors are used to detect the attenuation of the adjustable attenuator.

[0013] Preferably, the first-stage amplifier includes a fifth detector, a first amplification unit, a second amplification unit, and a first pump laser;

[0014] The control unit is connected to the first pump laser, and the first amplification unit and the second amplification unit are respectively connected to the pump laser;

[0015] The first pump laser is used to emit a laser signal, and the input terminal of the first amplification unit is used to receive the signal light and amplify the optical power of the signal light through the laser signal.

[0016] The fifth detector is connected to the input terminal of the first amplification unit and the control unit respectively, and the fifth detector is used to detect the optical power of the signal light;

[0017] The adjustable attenuator is disposed between the output end of the first amplification unit and the input end of the second amplification unit; the second amplification unit is used to receive the signal light amplified by the first amplification unit and further amplify the signal light through the laser signal.

[0018] Preferably, the second-stage amplifier includes a third amplification unit, a second pump laser, and a sixth detector;

[0019] The input terminal of the third amplification unit is connected to the output terminal of the dispersion compensation unit, and the sixth detector is connected to the output terminal of the third amplification unit and the control unit respectively. The sixth detector is used to detect the optical power of the signal light at the output terminal of the second stage amplifier.

[0020] The control unit is connected to the second pump laser, and the third amplification unit is connected to the second pump laser;

[0021] The third amplification unit is used to amplify the optical power of the signal light from the dispersion compensation unit through the laser signal emitted by the second pump laser.

[0022] Preferably, the first amplification unit, the second amplification unit, and the third amplification unit all include a wavelength division multiplexer and a doped optical fiber;

[0023] The wavelength division multiplexer in the first amplification unit is used to transmit the laser signal from the first pump laser and the signal light to the doped fiber in the first amplification unit; the wavelength division multiplexer in the second amplification unit is used to transmit the laser signal from the first pump laser and the signal light amplified by the first amplification unit to the doped fiber in the second amplification unit; the wavelength division multiplexer in the third amplification unit is used to transmit the laser signal from the second pump laser and the signal light amplified by the first stage amplifier to the doped fiber in the third amplification unit, so as to amplify the optical power of the signal light.

[0024] Secondly, a method for adjusting the gain slope is provided, including:

[0025] The control unit obtains the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the detection results of the second detector.

[0026] The control unit adjusts the attenuation of the adjustable attenuator according to the insertion loss value of the dispersion compensation unit to ensure the stability of the gain slope of the fiber amplifier output.

[0027] Preferably, the control unit obtains the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the second detector, specifically including:

[0028] The first detector detects the optical signal at the input of the dispersion compensation unit to obtain a first detection result, and then transmits the first detection result to the control unit.

[0029] The second detector detects the optical signal at the output of the dispersion compensation unit to obtain a second detection result, and then transmits the second detection result to the control unit.

[0030] The control unit obtains the insertion loss value of the dispersion compensation unit based on the first detection result and the second detection result.

[0031] Preferably, the control unit obtains the insertion loss value of the dispersion compensation unit based on the first detection result and the second detection result, including:

[0032] The insertion loss value of the dispersion compensation unit is obtained according to Formula 1;

[0033] Formula 1 is: I = P1 - P2;

[0034] Where I is the insertion loss value of the dispersion compensation unit, P1 is the first detection result, and P2 is the second detection result.

[0035] Preferably, the control unit adjusts the attenuation of the adjustable attenuator according to the insertion loss value of the dispersion compensation unit to ensure the stability of the gain slope of the fiber amplifier output, including:

[0036] The control unit obtains the attenuation amount of the adjustable attenuator based on the insertion loss value of the dispersion compensation unit;

[0037] The control unit adjusts the adjustable attenuator by adjusting the attenuation amount of the adjustable attenuator to stabilize the gain slope of the fiber amplifier output.

[0038] Preferably, the control unit obtains the attenuation amount of the adjustable attenuator based on the insertion loss value of the dispersion compensation unit, including:

[0039] The insertion loss value of the dispersion compensation unit is preset to obtain the preset insertion loss value;

[0040] The attenuation amount of the adjustable attenuator is obtained according to Formula 2.

[0041] Formula 2 is: A = P - I + F;

[0042] Where A is the attenuation of the adjustable attenuator, P is the preset insertion loss value, I is the insertion loss value of the dispersion compensation unit, and F is the deviation caused by the correlation loss in the fiber amplifier.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] This invention uses a first detector and a second detector to detect the dispersion compensation unit, and a control unit to obtain the insertion loss value of the dispersion compensation unit. Simultaneously, the control unit obtains the attenuation of the adjustable attenuator based on the insertion loss value of the dispersion compensation unit, and adjusts the attenuation of the adjustable attenuator according to the obtained attenuation value, thereby ensuring that the total insertion loss value of the optical path in the fiber amplifier remains stable. This ensures that the gain slope of the fiber amplifier output meets the requirements when the insertion loss value of the dispersion compensation unit changes. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the structure of an adjustable gain slope fiber amplifier provided in an embodiment of the present invention;

[0047] Figure 2 This is another structural schematic diagram of an adjustable gain slope fiber amplifier provided in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the specific structure of an adjustable gain slope fiber amplifier provided in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the structure of the first stage amplifier of an adjustable gain slope fiber amplifier provided in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the structure of the second-stage amplifier of an adjustable gain slope fiber amplifier provided in an embodiment of the present invention;

[0051] Figure 6 This is a flowchart illustrating a method for adjusting the gain slope provided in an embodiment of the present invention;

[0052] Figure 7 This is a flowchart illustrating the process of obtaining the insertion loss value of a dispersion compensation unit using a method for adjusting the gain slope provided in an embodiment of the present invention.

[0053] Figure 8 This is a schematic diagram of the process of obtaining the attenuation amount of an adjustable attenuator based on the insertion loss value of the dispersion compensation unit, according to an embodiment of the present invention.

[0054] Figure 9 This is a schematic diagram of the gain slope when the insertion loss of the dispersion compensation unit of the adjustable gain slope method provided in this embodiment of the invention is 10dB.

[0055] Figure 10 This is a schematic diagram of the gain slope curve when the insertion loss of the dispersion compensation unit of the adjustable gain slope method provided in this embodiment of the invention is 8dB.

[0056] Figure 11 This is a schematic diagram of the adjusted gain slope when the insertion loss of the dispersion compensation unit of the adjustable gain slope method provided in this embodiment of the invention is 8dB.

[0057] Figure 12 This is a schematic diagram of the gain slope when the insertion loss of the dispersion compensation unit of the adjustable gain slope method provided in this embodiment of the invention is 15dB.

[0058] Figure 13 This is a schematic diagram of the adjusted gain slope when the insertion loss of the dispersion compensation unit of an adjustable gain slope method provided in this embodiment of the invention is 15dB. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0060] In this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0061] In this invention, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0062] Example 1:

[0063] This embodiment provides an adjustable gain slope fiber amplifier, such as... Figure 1As shown, the system includes: a control unit, a first-stage amplifier, a dispersion compensation unit, and a second-stage amplifier. The output of the first-stage amplifier is connected to the input of the dispersion compensation unit, and the output of the dispersion compensation unit is connected to the input of the second-stage amplifier. A first detector is connected to the output of the first-stage amplifier, and a second detector is connected to the input of the second-stage amplifier. The first-stage amplifier includes an adjustable attenuator, and the control terminal of the adjustable attenuator, the first detector, and the second detector are respectively connected to the control unit. The control unit is used to obtain the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the second detector. The control unit is also used to adjust the attenuation of the adjustable attenuator based on the insertion loss value of the dispersion compensation unit to ensure the stability of the gain slope of the fiber amplifier output.

[0064] In this design, two stages of amplifiers are set before and after the dispersion compensation unit. Therefore, the gain slope of the fiber amplifier output often needs to be adjusted with the help of an adjustable attenuator. The insertion loss in the optical path is adjusted to achieve the required gain slope.

[0065] The control unit, as the core of the entire system, can be a Field-Programmable Gate Array (FPGA). The control unit is responsible for adjusting the attenuation of the adjustable attenuator and adjusting the performance of the fiber amplifier based on the detection results of the first and second detectors. The first-stage amplifier is responsible for initially amplifying the incoming signal light. The dispersion compensation unit is used to compensate for dispersion during signal transmission. The second-stage amplifier is used to further amplify the signal light processed by the dispersion compensation unit. The control unit calculates the insertion loss value of the dispersion compensation unit by acquiring data from the first and second detectors, and adjusts the attenuation of the adjustable attenuator based on the insertion loss value to compensate for the optical signal loss introduced by the dispersion compensation unit and maintain a stable gain slope for the entire system.

[0066] In a preferred embodiment, both the first detector and the second detector can be photodiodes (PDs). The functions of the first detector and the second detector also include: in an optical path with a dispersion compensation unit, the dispersion compensation unit is an indispensable condition, so it is necessary to monitor the insertion loss value of the dispersion compensation unit in real time. The first detector and the second detector will sequentially determine: whether the current dispersion compensation unit is in normal working condition, the difference between the current state and the previous state, whether the current dispersion compensation unit is in a steady state, and filter out the error or unstable state of the current dispersion compensation unit, etc.

[0067] Specifically, the following steps are taken: The power in the current optical path is detected. Based on the power detection, it is determined whether the dispersion compensation unit is in an open-circuit state (i.e., the second detector has no signal), a normal path state (i.e., the insertion loss measured by the first and second detectors deviates from the set value by less than 0.3 dB), or a path state but the dispersion unit insertion loss is abnormal (i.e., the insertion loss measured by the first and second detectors deviates from the set value by more than 0.3 dB). The stability of the power in the current optical path is determined by comparing it with the optical power issued by the control unit. To avoid errors caused by chance or inaccuracies in instantaneous detection, the first and second detectors will perform at least three detections within milliseconds, while simultaneously performing sliding filtering to determine whether the current state is stable (i.e., requiring...). The optical power measured by the first and second detectors deviates from the transmitted power by less than 0.2 dB. Considering the jitter of optical power or the impact of jitter during actual operation, the first and second detectors will determine the jitter of optical power. If the jitter amplitude of the dispersion compensation unit is less than 0.3 dB, it is considered to be in a stable state; otherwise, it is considered to be in an unstable state, and the insertion loss value of the dispersion compensation unit needs to be re-evaluated and obtained. Finally, the first and second detectors can also compare the current state with the previous state. If the insertion loss value of the dispersion compensation unit has not changed, it is assumed that the working state of the fiber amplifier has not changed, and the previous state can be used for calculation. If the insertion loss value of the dispersion compensation unit has changed, the set value of the insertion loss value of the dispersion compensation unit will be judged, and then an alarm will be triggered.

[0068] In normal operating mode, when the insertion loss of the dispersion compensation unit is set to a certain fixed value, if the insertion loss detected by the first detector and the second detector is greater than the fixed value, the insertion loss of the adjustable attenuator is reduced accordingly; if the insertion loss detected by the first detector and the second detector is less than the fixed value, the insertion loss of the adjustable attenuator is increased accordingly.

[0069] In this embodiment, the dispersion compensation unit is detected by a first detector and a second detector, and the insertion loss value of the dispersion compensation unit is obtained by a control unit. At the same time, the control unit obtains the attenuation of the adjustable attenuator based on the insertion loss value of the dispersion compensation unit, and adjusts the attenuation of the adjustable attenuator based on the obtained attenuation value to ensure that the total insertion loss value of the optical path in the fiber amplifier remains stable, so as to ensure that the gain slope of the fiber amplifier output meets the requirements when the insertion loss value of the dispersion compensation unit changes.

[0070] Other structures in the fiber optic amplifier will be described below.

[0071] In a preferred embodiment, such as Figure 2 As shown, a third detector is connected to the input terminal of the adjustable attenuator, and a fourth detector is connected to the output terminal of the adjustable attenuator; the third detector and the fourth detector are respectively connected to the control unit, and the third detector and the fourth detector are used to detect the attenuation of the adjustable attenuator.

[0072] Throughout the process, the third and fourth detectors located before and after the adjustable attenuator detect the attenuation of the adjustable attenuator. When the insertion loss value of the dispersion compensation unit changes, the control unit will synchronously adjust the attenuation of the adjustable attenuator on a millisecond scale, thereby achieving the effect of keeping the total insertion loss of the optical path as constant as possible. In this way, the overall output gain slope will remain basically unchanged, which meets the usage requirements.

[0073] like Figure 3 The specific structure of the fiber optic amplifier is shown below. The specific structures of the first-stage amplifier and the second-stage amplifier will be described next.

[0074] In a preferred embodiment, such as Figure 4 As shown, the first-stage amplifier includes a fifth detector, a first amplification unit, a second amplification unit, and a first pump laser; the control unit is connected to the first pump laser, and the first and second amplification units are respectively connected to the pump laser; the first pump laser is used to emit a laser signal, and the input terminal of the first amplification unit is used to receive the signal light and amplify the optical power of the signal light through the laser signal; the fifth detector is connected to both the input terminal of the first amplification unit and the control unit, and the fifth detector is used to detect the optical power of the signal light; the adjustable attenuator is disposed between the output terminal of the first amplification unit and the input terminal of the second amplification unit; the second amplification unit is used to receive the signal light amplified by the first amplification unit and further amplify the signal light through the laser signal.

[0075] More specifically, the input end of the fiber amplifier is equipped with an optical coupler CPL1. The common end of the optical coupler CPL1 serves as the input port of the fiber amplifier, and the splitting end of the optical coupler CPL1 is connected to the fifth detector, which is used to detect the optical power of the input signal light. The optical coupler CPL1 can be a 2 / 98 optical coupler, meaning that 2% of the signal light is used to be detected by the fifth detector, and 98% of the signal light is used to be transmitted to other subsequent structures. The first pump laser is connected to an optical coupler CPL2, which can be selected with a 30 / 70 splitting ratio, meaning that 30% of the laser signal is sent to the first amplification unit, and 70% of the laser signal is used to be transmitted to the second amplification unit. More specifically, the first stage amplifier also includes multiple optical isolators (ISOs) and optical couplers CPLs; see [link to specific connection structure] for details. Figure 4 Other structures will not be described in detail in this embodiment.

[0076] In a preferred embodiment, such as Figure 5 As shown, the second-stage amplifier includes a third amplification unit, a second pump laser, and a sixth detector. The input terminal of the third amplification unit is connected to the output terminal of the dispersion compensation unit. The sixth detector is connected to both the output terminal of the third amplification unit and the control unit. The sixth detector is used to detect the optical power of the signal light at the output terminal of the second-stage amplifier. The control unit is connected to the second pump laser, and the third amplification unit is connected to the second pump laser. The third amplification unit is used to amplify the optical power of the signal light from the dispersion compensation unit using the laser signal emitted by the second pump laser.

[0077] The specific structure of the second-stage amplifier can be found in [reference needed]. Figure 5 Other structures will not be described in detail in this embodiment.

[0078] In a preferred embodiment, such as Figure 4 and Figure 5As shown, the first amplification unit, the second amplification unit, and the third amplification unit all include a wavelength division multiplexer (WDM) and a doped fiber (EDF). The WDM in the first amplification unit is used to transmit the laser signal from the first pump laser and the signal light to the doped fiber in the first amplification unit. The WDM in the second amplification unit is used to transmit the laser signal from the first pump laser and the signal light amplified by the first amplification unit to the doped fiber in the second amplification unit. The WDM in the third amplification unit is used to transmit the laser signal from the second pump laser and the signal light amplified by the first stage amplifier to the doped fiber in the third amplification unit, thereby amplifying the optical power of the signal light.

[0079] The primary function of the first and second pump lasers is to provide energy to excite dopants (typically rare-earth ions such as erbium and yttrium) in the optical fiber. These dopants amplify the optical signal during stimulated emission, thus achieving signal amplification. The output wavelength of the pump laser is typically selected to efficiently excite the dopants. The first pump laser can be a 974nm wavelength pump laser. When the energy from the pump laser is input into the optical fiber, it excites the dopants, putting them in an excited state. When the optical signal passes through the excited dopant region, these dopants release energy, thereby amplifying the optical signal. The pump lasers in the fiber amplifier typically employ high-power laser diodes or solid-state lasers to ensure sufficient energy is delivered into the optical fiber.

[0080] The doped fiber can be an erbium-doped fiber. The output of the tunable optical attenuator is connected to the wavelength division multiplexer of the second amplification unit. The output of the erbium-doped fiber in the second amplification unit is also connected to a gain flattening filter (GFF). The signal light is input from the input port of the fiber amplifier. A small portion of the signal light is collected by the fifth detector, and most of the signal light passes through the wavelength division multiplexer of the first amplification unit and is combined with the laser signal emitted by the first pump laser before being transmitted to the erbium-doped fiber. The erbium ions in the erbium-doped fiber are excited to a high-energy state by the pump light, causing a population inversion and thus generating stimulated emission. This amplifies the input signal light at the output of the first amplification unit. The second and third amplification units work similarly and will not be described in detail in this embodiment.

[0081] Example 2:

[0082] In Example 1, an adjustable gain slope fiber amplifier was proposed. In this example, a method for adjusting the gain slope will be proposed, such as... Figure 6 As shown, it includes:

[0083] Step 101: The control unit obtains the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the second detector.

[0084] In a preferred embodiment, such as Figure 7 As shown, step 101 specifically includes:

[0085] Step 1011: Detect the optical signal at the input of the dispersion compensation unit using the first detector to obtain a first detection result, and transmit the first detection result to the control unit.

[0086] The first detector is located at the output of the first-stage amplifier and is used to measure the intensity of the light signal after it has been processed by the first-stage amplifier, that is, the intensity of the light signal entering the dispersion compensation unit.

[0087] Step 1012: Detect the optical signal at the output of the dispersion compensation unit using the second detector to obtain a second detection result, and transmit the second detection result to the control unit.

[0088] The second detector is located at the input of the second-stage amplifier and is used to measure the intensity of the light signal after passing through the dispersion compensation unit, that is, the intensity of the light signal emitted by the dispersion compensation unit.

[0089] Step 1013: The control unit obtains the insertion loss value of the dispersion compensation unit based on the first detection result and the second detection result.

[0090] The insertion loss value of the dispersion compensation unit is obtained according to Formula 1;

[0091] Formula 1 is: I = P1 - P2;

[0092] Where I is the insertion loss value of the dispersion compensation unit, P1 is the first detection result, and P2 is the second detection result.

[0093] The control unit compares the readings of the first and second detectors, and the difference reflects the insertion loss introduced by the dispersion compensation unit. The insertion loss value is the portion of the signal lost after passing through the dispersion compensation unit, reflecting the energy loss during the dispersion compensation process. The control unit automatically adjusts the attenuation of the adjustable attenuator based on the acquired insertion loss value to compensate for the loss introduced by dispersion compensation, ensuring that the gain slope of the entire system remains stable.

[0094] Step 102: The control unit adjusts the attenuation of the adjustable attenuator according to the insertion loss value of the dispersion compensation unit to ensure the stability of the gain slope of the fiber amplifier output.

[0095] In a preferred embodiment, such as Figure 8As shown, step 102 specifically includes:

[0096] Step 1021: The control unit obtains the attenuation amount of the adjustable attenuator based on the insertion loss of the dispersion compensation unit.

[0097] The insertion loss value of the dispersion compensation unit is preset to obtain the preset insertion loss value;

[0098] The attenuation amount of the adjustable attenuator is obtained according to Formula 2.

[0099] Formula 2 is: A = P - I + F;

[0100] Where A is the attenuation of the adjustable attenuator, P is the preset insertion loss value, I is the insertion loss value of the dispersion compensation unit, and F is the deviation caused by the correlation loss in the fiber amplifier.

[0101] Taking a dispersion compensation unit with a 10dB insertion loss as an example, the initial design requires adding 10dB to the optical path gain based on the specifications. During use, when the insertion loss of the dispersion compensation unit is less than 10dB, the insertion loss value is obtained from the detection results of the first and second detectors, and then subtracted from 10dB to obtain the additional attenuation amount of the adjustable attenuator, thus maintaining the total insertion loss. When the insertion loss of the dispersion compensation unit is greater than 10dB, the insertion loss value is obtained from the detection results of the first and second detectors, and then subtracted from 10dB to obtain the additional attenuation amount of the adjustable attenuator, allowing for adjustment of the adjustable attenuator. Furthermore, during actual testing, a fixed parameter can be added to the adjustable attenuator to balance the attenuator at various slopes or to compensate for wavelength loss in optical devices. This fixed parameter represents the deviation caused by wavelength-dependent loss, polarization-dependent loss, etc., and can be obtained through actual testing. For example: if the insertion loss of the dispersion compensation unit is set to 10dB, and the actual insertion loss is calculated to be 8dB, then the adjustable attenuator will attenuate by an additional 2dB if the fixed parameters are ignored; if the actual insertion loss is calculated to be 15dB, then the adjustable attenuator will attenuate by an additional 5dB if the fixed parameters are ignored.

[0102] Step 1022: The control unit adjusts the adjustable attenuator by adjusting the attenuation amount of the adjustable attenuator to stabilize the gain slope of the fiber amplifier output.

[0103] The control unit can send commands to the adjustable attenuator to adjust its attenuation. This is achieved by changing the internal optical components of the adjustable attenuator. The adjustment of the attenuation must be very precise to ensure accurate adjustment of the gain slope. After adjustment, the control unit continues to monitor the intensity of the optical signal and the gain slope to ensure the adjustment achieves the desired effect. If the environment changes or the input signal strength changes, the system will readjust the attenuation of the adjustable attenuator as needed. The system continuously monitors various parameters to ensure long-term stable operation. Upon detecting any abnormalities, the system can take measures including adjusting the attenuation, sending warnings, or activating backup mechanisms.

[0104] Through this process, the control unit can effectively adjust the adjustable attenuator to ensure that the gain slope of the fiber amplifier output remains stable. Figure 9 As shown, when the optical path set gain (excluding dispersion compensation insertion loss) is 20dB and the insertion loss of the dispersion compensation unit is 10dB, the gain slope of the fiber amplifier output is 0.025.

[0105] like Figure 10 and Figure 11 As shown, when the insertion loss of the dispersion compensation unit decreases to 8dB, the gain slope of the fiber amplifier output before adjustment becomes 1.36, and after adjustment it returns to 0.064. Figure 12 and Figure 13 As shown, when the insertion loss value of the dispersion compensation unit is increased to 15dB, the gain slope of the fiber amplifier output before adjustment becomes 4.12, and after adjustment it recovers to 0.084. It can be seen that the adjustable gain slope method proposed in this embodiment can effectively ensure that the total insertion loss value of the optical path in the fiber amplifier remains stable, so as to ensure that the gain slope of the fiber amplifier output meets the requirements when the insertion loss value of the dispersion compensation unit changes.

[0106] For the specific structure of the fiber optic amplifier, please refer to Embodiment 1, which will not be repeated in this embodiment.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adjustable gain slope fiber amplifier, characterized in that, include: The system comprises a control unit, a first-stage amplifier, a dispersion compensation unit, and a second-stage amplifier; the output of the first-stage amplifier is connected to the input of the dispersion compensation unit, and the output of the dispersion compensation unit is connected to the input of the second-stage amplifier. A first detector is connected to the output terminal of the first stage amplifier, and a second detector is connected to the input terminal of the second stage amplifier; the first stage amplifier includes an adjustable attenuator, and the control terminal of the adjustable attenuator, the first detector, and the second detector are respectively connected to the control unit; The control unit is used to obtain the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the detection results of the second detector. The control unit is also used to adjust the attenuation of the adjustable attenuator according to the insertion loss value of the dispersion compensation unit, so as to ensure the stability of the gain slope of the fiber amplifier output. A third detector is connected to the input terminal of the adjustable attenuator, and a fourth detector is connected to the output terminal of the adjustable attenuator; the third detector and the fourth detector are respectively connected to the control unit, and the third detector and the fourth detector are used to detect the attenuation of the adjustable attenuator; The calculation method for the attenuation of the adjustable attenuator includes: The insertion loss value of the dispersion compensation unit is preset to obtain the preset insertion loss value; The attenuation amount of the adjustable attenuator is obtained according to Formula 2. Formula 2 is: ; in, The attenuation amount of the adjustable attenuator. The preset value for insertion loss is... The insertion loss value of the dispersion compensation unit is... This refers to the deviation caused by the correlation loss in the fiber amplifier.

2. The fiber amplifier with adjustable gain slope according to claim 1, characterized in that, The first-stage amplifier includes a fifth detector, a first amplification unit, a second amplification unit, and a first pump laser; The control unit is connected to the first pump laser, and the first amplification unit and the second amplification unit are respectively connected to the pump laser; The first pump laser is used to emit a laser signal, and the input terminal of the first amplification unit is used to receive the signal light and amplify the optical power of the signal light through the laser signal. The fifth detector is connected to the input terminal of the first amplification unit and the control unit respectively, and the fifth detector is used to detect the optical power of the signal light; The adjustable attenuator is disposed between the output end of the first amplification unit and the input end of the second amplification unit; the second amplification unit is used to receive the signal light amplified by the first amplification unit and further amplify the signal light through the laser signal.

3. The fiber amplifier with adjustable gain slope according to claim 2, characterized in that, The second-stage amplifier includes a third amplification unit, a second pump laser, and a sixth detector; The input terminal of the third amplification unit is connected to the output terminal of the dispersion compensation unit, and the sixth detector is connected to the output terminal of the third amplification unit and the control unit respectively. The sixth detector is used to detect the optical power of the signal light at the output terminal of the second stage amplifier. The control unit is connected to the second pump laser, and the third amplification unit is connected to the second pump laser; The third amplification unit is used to amplify the optical power of the signal light from the dispersion compensation unit through the laser signal emitted by the second pump laser.

4. The fiber amplifier with adjustable gain slope according to claim 3, characterized in that, The first amplification unit, the second amplification unit, and the third amplification unit all include a wavelength division multiplexer and a doped optical fiber; The wavelength division multiplexer in the first amplification unit is used to transmit the laser signal from the first pump laser and the signal light to the doped fiber in the first amplification unit; the wavelength division multiplexer in the second amplification unit is used to transmit the laser signal from the first pump laser and the signal light amplified by the first amplification unit to the doped fiber in the second amplification unit; the wavelength division multiplexer in the third amplification unit is used to transmit the laser signal from the second pump laser and the signal light amplified by the first stage amplifier to the doped fiber in the third amplification unit, so as to amplify the optical power of the signal light.

5. A method for adjusting the gain slope, characterized in that, The method for adjusting the gain slope is implemented in the fiber amplifier with adjustable gain slope as described in any one of claims 1 to 4, comprising: The control unit obtains the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the detection results of the second detector. The control unit adjusts the attenuation of the adjustable attenuator according to the insertion loss value of the dispersion compensation unit to ensure the stability of the gain slope of the fiber amplifier output.

6. The method for adjusting the gain slope according to claim 5, characterized in that, The control unit obtains the insertion loss value of the dispersion compensation unit based on the detection results of the first detector and the second detector, specifically including: The first detector detects the optical signal at the input of the dispersion compensation unit to obtain a first detection result, and then transmits the first detection result to the control unit. The second detector detects the optical signal at the output of the dispersion compensation unit to obtain a second detection result, and then transmits the second detection result to the control unit. The control unit obtains the insertion loss value of the dispersion compensation unit based on the first detection result and the second detection result.

7. The method for adjusting the gain slope according to claim 6, characterized in that, The control unit obtains the insertion loss value of the dispersion compensation unit based on the first detection result and the second detection result, including: The insertion loss value of the dispersion compensation unit is obtained according to Formula 1; Formula 1 is: ; in, The insertion loss value of the dispersion compensation unit is... The first detection result, This is the second detection result.

8. The method for adjusting the gain slope according to claim 7, characterized in that, The control unit adjusts the attenuation of the adjustable attenuator according to the insertion loss value of the dispersion compensation unit to ensure the stability of the gain slope of the fiber amplifier output, including: The control unit obtains the attenuation amount of the adjustable attenuator based on the insertion loss value of the dispersion compensation unit; The control unit adjusts the adjustable attenuator by adjusting the attenuation amount of the adjustable attenuator to stabilize the gain slope of the fiber amplifier output.

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