Control method and system of high-power optical fiber amplifier

Abstract

The invention discloses a control method and system of a high-power optical fiber amplifier, and relates to the technical field of optical fiber amplifiers, and the high-power optical fiber amplifier comprises a first-stage gain unit and a second-stage gain unit which are sequentially arranged along the transmission direction of light; the control method of the high-power optical fiber amplifier comprises the following steps: starting the high-power optical fiber amplifier according to a starting sequence of firstly starting a first-stage gain unit and then starting a second-stage gain unit; and closing the high-power optical fiber amplifier according to a closing sequence of firstly closing the second-stage gain unit and then closing the first-stage gain unit. According to the control method and system, the optical fiber amplifier can be controlled to realize relatively high power output, so that the optical fiber amplifier is suitable for being applied to a hollow-core optical fiber transmission system, the high-power optical fiber amplifier can be prevented from generating a huge reverse ASE signal to burn an optical path device under the condition of no input optical signal, and the application safety and reliability of the optical fiber amplifier are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber amplifiers, and in particular to a control method and system for a high-power optical fiber amplifier. Background Art

[0002] To fully tap the potential of optical communication networks, longer wavelength division multiplexing (WDM) system transmission distances have become the preferred solution and research hotspot in the field of fiber-optic communications. However, the output power of traditional EDFAs that support multi-wavelength transmission is usually not large enough, and traditional fiber-optic transmission systems have serious nonlinear effects, making them unable to carry out long-distance single-span transmission.

[0003] In recent years, hollow-core fiber transmission systems have gained popularity. Because they transmit through air, nonlinear effects during transmission are significantly reduced, creating a pressing need for high-power multi-wavelength amplifiers. Amplifiers supporting hollow-core fiber transmission boast high output powers (over 33dBm). Furthermore, because they transmit through air, nonlinear effects are minimal, effectively avoiding performance degradation caused by nonlinear effects such as four-wave mixing, Raman frequency shift, and Brillouin scattering. This makes transmission spans greater than 300 kilometers feasible. However, the output power of conventional fiber amplifiers has reached saturation, making them incapable of meeting the demands of hollow-core fiber transmission systems. Furthermore, conventional high-power amplifiers generate significant reverse ASE (stimulated spontaneous emission) signals in the absence of an input optical signal, which can easily damage optical path components such as multimode pumps. Summary of the Invention

[0004] In response to the above problems and technical requirements, the present inventors have proposed a control method and system for a high-power optical fiber amplifier. The technical solution of the present invention is as follows:

[0005] A control method for a high-power optical fiber amplifier, wherein the high-power optical fiber amplifier comprises a first-stage gain unit and a second-stage gain unit sequentially arranged along a light transmission direction;

[0006] The control method of the high-power optical fiber amplifier comprises:

[0007] The high-power fiber amplifier is turned on in the order of first turning on the first-stage gain unit and then turning on the second-stage gain unit;

[0008] The high-power optical fiber amplifier is shut down in the order of shutting down the second-stage gain unit first and then shutting down the first-stage gain unit.

[0009] A further technical solution is to provide a switch signal for controlling the working state of the optical fiber amplifier, and to turn on the optical fiber amplifier when the switch signal is at a valid level;

[0010] When the optical fiber amplifier is turned on, the first-stage gain unit is controlled to be turned on first, and the output optical power of the first-stage gain unit is collected. When the output optical power of the first-stage gain unit reaches the threshold optical power, the second-stage gain unit is controlled to be turned on.

[0011] A further technical solution is to collect the input optical power and switching signal of the high-power optical fiber amplifier during operation of the high-power optical fiber amplifier, and to sequentially shut down the second-stage gain unit and the first-stage gain unit when the input optical power is lower than the shutdown threshold and / or the switching signal is at an invalid level.

[0012] A further technical solution is to provide a power management module, the power management module is connected to a power supply, and the power management module is used to supply power to the first-stage gain unit and the second-stage gain unit;

[0013] During the operation of the high-power optical fiber amplifier, a power failure detection is performed on the power supply, and when the power failure is detected, the power management module is controlled to stop supplying power to the second-stage gain unit, so as to shut down the second-stage gain unit.

[0014] A control system for a high-power optical fiber amplifier, used to execute the above-mentioned control method for the high-power optical fiber amplifier;

[0015] The control system of the high-power optical fiber amplifier includes an adaptively connected control module, a first gain control loop and a second gain control loop, wherein the first gain control loop is connected to the first-stage gain unit, and the second gain control loop is connected to the second-stage gain unit;

[0016] When the optical fiber amplifier is turned on, the control module controls the first-stage gain unit to be turned on through the first gain control loop. The first gain control loop is used to collect the output optical power of the first-stage gain unit and transmit it to the control module. When the output optical power of the first-stage gain unit is greater than the threshold optical power, the control module controls the second-stage gain unit to be turned on through the second gain control loop.

[0017] When the optical fiber amplifier is turned off, the control module first controls the second-stage gain unit to be turned off through the second gain control loop, and then controls the first-stage gain unit to be turned off through the first gain control loop.

[0018] A further technical solution is that the control module receives a switch signal for controlling the switch state of the high-power optical fiber amplifier, and the control module collects input optical power through a first gain control loop;

[0019] The control module turns on the high-power fiber amplifier when the switch signal is at a valid level, and turns off the high-power fiber amplifier when the input optical power is lower than a shutdown threshold and / or the switch signal is at an invalid level.

[0020] A further technical solution is that the first-stage gain unit includes a first photodetector, a fourth photodetector, a first pump source and a second pump source;

[0021] The control system includes a first linear amplification module, the control module includes an MCU, a DAC and an ADC; the first gain control loop includes a first PID control module, a first current-voltage conversion module, a second current-voltage conversion module and a second linear amplification module;

[0022] The input end of the first current-voltage conversion module is connected to the negative electrode of the first photodetector, the input end of the first linear amplification module is connected to the positive electrode of the first photodetector, the output end of the first current-voltage conversion module is connected to the ADC, and the output end of the first linear amplification module is connected to the first input end of the first PID control module;

[0023] The input end of the second linear amplification module is connected to the positive electrode of the fourth photodetector, and the output end of the second linear amplification module is connected to the second input end of the first PID control module;

[0024] The input end of the second current-voltage conversion module is connected to the negative electrode of the fourth photodetector, and the output end of the second current-voltage conversion module is connected to the ADC;

[0025] The first output end of the first PID control module is connected to the first pump source, and the second output end of the first PID control module is connected to the second pump source.

[0026] A further technical solution is that the first linear amplification module is used to generate a first voltage signal according to the input optical signal of the high-power optical fiber amplifier, and the first current-voltage conversion module is used to generate a second voltage signal according to the input optical signal of the high-power optical fiber amplifier;

[0027] The second linear amplification module is used to generate a third voltage signal according to the output optical signal of the first-stage gain unit, and the second current-voltage conversion module is used to generate a fourth voltage signal according to the output optical signal of the first-stage gain unit.

[0028] A further technical solution is that the second-stage gain unit includes a fifth photodetector, a first multi-mode pump source and a second multi-mode pump source;

[0029] The second gain control loop includes a second PID control module, a third current-voltage conversion module and a third linear amplification module;

[0030] The input end of the third current-voltage conversion module is connected to the negative electrode of the fifth photodetector, and the input end of the third linear amplification module is connected to the positive electrode of the fifth photodetector;

[0031] The output end of the third current-voltage conversion module is connected to the ADC, the output end of the third linear amplification module is connected to the first input end of the second PID control module, and the output end of the first linear amplification module is also connected to the second input end of the second PID control module;

[0032] The third linear amplification module is used to generate a fifth voltage signal according to the output optical signal of the second-stage gain unit, and the third current-voltage conversion module is used to generate a sixth voltage signal according to the output optical signal of the second-stage gain unit;

[0033] A first output end of the second PID control module is connected to a first multi-mode pump source, and a second output end of the second PID control module is connected to a second multi-mode pump source.

[0034] Its further technical solution is that it also includes a connector, a power management module and a power failure detection module;

[0035] The power supply is connected to the power management module through the connector, and the power management module is used to supply power to the control module, the power failure detection module, the first gain control loop, the second gain control loop, the first-stage gain unit, and the second-stage gain unit;

[0036] The power management module includes a first DC-DC conversion circuit, which is used to convert the power supply voltage into the operating voltage required by the first multi-mode pump source and the second multi-mode pump source, and supply power to the first multi-mode pump source and the second multi-mode pump source;

[0037] When the power failure detection module detects that the power supply is powered off, the first DC-DC conversion circuit is controlled to stop supplying power to the first multi-mode pump source and the second multi-mode pump source, so as to shut down the second-stage gain unit;

[0038] The power failure detection module includes a voltage comparator U1, a capacitor C1, a resistor R1, a resistor R2, a resistor R3 and a resistor R4, wherein:

[0039] The non-inverting input terminal of the voltage comparator U1 is connected to one end of the resistor R1 and one end of the resistor R2, the other end of the resistor R1 is connected to the power supply, and the other end of the resistor R2 is connected to the analog ground;

[0040] The inverting input terminal of the voltage comparator U1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the reference voltage source, and the output terminal of the voltage comparator U1 is connected to the enable terminal of the first DC-DC conversion circuit through the resistor R4;

[0041] One end of the capacitor C1 is connected to the power supply terminal of the voltage comparator U1 , and the other end of the capacitor C1 is connected to the ground terminal of the voltage comparator U1 .

[0042] The beneficial technical effects of the present invention are:

[0043] The present invention provides a control method and system for a high-power fiber amplifier, capable of achieving high power output. The system is suitable for hollow-core fiber transmission systems and supports multiwavelength transmission. Furthermore, by controlling the on / off sequence of the first-stage and second-stage gain units in the fiber amplifier, the system prevents the high-power fiber amplifier from generating a large reverse ASE signal in the absence of an input optical signal, potentially damaging optical components such as the multimode pump, thereby improving the safety and reliability of the application.

[0044] The present invention can also perform power-off detection on the optical fiber amplifier, so that in the extreme case of a sudden power outage, the second-stage gain unit of the optical fiber amplifier can still be turned off before the first-stage gain unit, ensuring that the entire high-power optical fiber amplifier can operate safely and reliably in all application scenarios, regardless of whether the built-in MCU is operating normally or in a power-off and loss-of-control state. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a structural block diagram of an embodiment of a high-power optical fiber amplifier control system provided by the present invention.

[0046] Figure 2 The figure is a schematic diagram of the optical path of an embodiment of the high-power optical fiber amplifier provided by the present invention.

[0047] Figure 3 This is a circuit diagram of an embodiment of a power failure detection module provided by the present invention.

[0048] Figure 1: Input signal port, 2: First optical splitter, 3: First isolator, 4: First wavelength division multiplexer, 5: First section of erbium-doped fiber, 6: Second wavelength division multiplexer, 7: First IGFF unit, 8: Third wavelength division multiplexer, 9: Second section of erbium-doped fiber, 10: Second IGFF unit, 11: Second optical splitter, 12: Variable attenuator, 13: Third optical splitter, 14: Fourth wavelength division multiplexer, 15: Third section of erbium-doped fiber, 16: Second isolator Isolator, 17-fourth optical splitter, 18-multimode pump combiner, 19-first section of erbium-ytterbium co-doped fiber, 20-third isolator, 21-fifth optical splitter, 22-output signal port, 23-first photodetector, 24-first pump source, 25-second photodetector, 26-third photodetector, 27-second pump source, 28-fourth photodetector, 29-first multimode pump source, 30-second multimode pump source, 31-fifth photodetector. DETAILED DESCRIPTION

[0049] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the relevant content, rather than to limit the present disclosure.

[0050] The present invention provides a control method for a high-power optical fiber amplifier, wherein the high-power optical fiber amplifier comprises a first-stage gain unit and a second-stage gain unit sequentially arranged along a light transmission direction;

[0051] The control method of the high-power optical fiber amplifier comprises:

[0052] The high-power fiber amplifier is turned on in the order of first turning on the first-stage gain unit and then turning on the second-stage gain unit;

[0053] The high-power optical fiber amplifier is shut down in the order of shutting down the second-stage gain unit first and then shutting down the first-stage gain unit.

[0054] Specifically, in the high-power fiber amplifier, the first-stage gain unit is used to amplify the input signal light to a level close to the saturated output optical power of conventional erbium fiber. The pump source in the second-stage gain unit can utilize a multimode pump source with a maximum drive current of 13A and a pump power of 10,000mW, amplifying the output optical power of the first-stage gain unit to a high power of over 33dBm, meeting the requirements of hollow-core fiber transmission systems. The detailed structure of the optical circuit of the high-power fiber amplifier can be found in the following description.

[0055] Because the fiber amplifier provided by this invention boasts a maximum total output power exceeding 33dBm, the high current driving the multimode pump source from the second-stage gain unit in the absence of signal input can generate a significant reverse ASE signal, potentially damaging optical path components such as isolators, GFFs (gain flattening filters), and multimode pump sources. Therefore, when starting up the fiber amplifier, the first-stage gain unit must be activated first, followed by the second-stage gain unit.

[0056] In a specific implementation, a switch signal is provided for controlling the operating state of the optical fiber amplifier. When the switch signal is at an effective level, the optical fiber amplifier is turned on. When the optical fiber amplifier is turned on, the first-stage gain unit is first controlled to turn on, and the output optical power of the first-stage gain unit is collected. When the output optical power of the first-stage gain unit reaches a threshold optical power, the second-stage gain unit is controlled to turn on. At this time, the output optical power of the first-stage gain unit is relatively stable, and a large ASE signal will not be generated after the second-stage gain unit is turned on. After the second-stage gain unit is turned on, the driving current of the multimode pump source in the second-stage gain unit will slowly increase until the output optical power of the second-stage gain unit reaches the second target optical power, ensuring the safe and reliable operation of the high-power optical fiber amplifier. The control method of the first-stage gain unit and the second-stage gain unit can be referred to the following description. The threshold optical power can be set according to actual conditions.

[0057] When shutting down the high-power amplifier, for safety and reliability reasons, to prevent the second-stage gain unit from generating a large ASE signal due to a lack of signal light input, a shutdown sequence opposite to the startup sequence is adopted: first shutting down the second-stage gain unit, then shutting down the first-stage gain unit. Specifically, during operation of the high-power fiber amplifier, the input optical power and switching signal of the high-power fiber amplifier are collected. When the input optical power falls below a shutdown threshold and / or the switching signal reaches an invalid level, the second-stage gain unit and the first-stage gain unit are shut down in sequence. The shutdown threshold can be set according to actual needs.

[0058] Typically, the switching signal, along with the collected output and input optical power of the first-stage gain unit, is input to an MCU. The MCU's built-in firmware algorithm implements the control logic to control the operating states of the first and second gain units. However, in the extreme case of a power failure, the MCU loses control and is unable to complete the logic control, effectively preventing the fiber amplifier from switching on and off.

[0059] Therefore, to prevent the second-stage gain unit from generating a large ASE signal due to a lack of signal light input when the power supply fails, the present invention performs a power failure detection on the high-power fiber amplifier during operation. Upon detection, the second-stage gain unit is immediately shut down. Subsequently, the first-stage gain unit is naturally shut down as power is depleted, achieving a shutdown sequence in which the second-stage gain unit is shut down first, followed by the first-stage gain unit. This ensures that the high-power amplifier can operate safely and reliably even under extreme power outage conditions, preventing damage to internal components.

[0060] In a specific implementation, the power supply is generally input to a power management module, which then supplies power to the first-stage gain unit and the second-stage gain unit. During operation of the high-power fiber amplifier, a power failure detection is performed on the power supply of the high-power fiber amplifier. Upon detecting a power failure, the power management module is controlled to stop supplying power to the second-stage gain unit, thereby rapidly shutting down the second-stage gain unit. The specific method for performing power failure detection is described below.

[0061] The present invention also provides a control system for a high-power optical fiber amplifier, which is used to execute the control method of the high-power optical fiber amplifier;

[0062] like Figure 1 As shown, the control system of the high-power optical fiber amplifier includes an adaptively connected control module, a first gain control loop (Gain control loop 1) and a second gain control loop (Gain control loop 2), wherein the first gain control loop is connected to the first-stage gain unit, and the second gain control loop is connected to the second-stage gain unit;

[0063] When the optical fiber amplifier is turned on, the control module turns on the first-stage gain unit through the first gain control loop, and the first gain control loop is used to collect the output optical power of the first-stage gain unit and transmit it to the control module. When the output optical power of the first-stage gain unit is greater than the threshold optical power, the control module turns on the second-stage gain unit through the second gain control loop;

[0064] When shutting down the optical fiber amplifier, the control module first shuts down the second-stage gain unit through the second gain control loop, and then shuts down the first-stage gain unit through the first gain control loop.

[0065] Specifically, the control module is connected to the first gain loop and the second gain loop, and the control module includes a DAC (Digital-to-Analog Converter), an ADC (Analog-to-Digital Converter) and an MCU. As can be seen from the above description, the optical fiber amplifier can be controlled to be turned on or off by a switch signal. The system also includes a connector, which is connected to the MCU, and the MCU is connected to the DAC and ADC. The switch signal is connected to the MCU by the connector. When the MCU detects that the switch signal is a valid signal, it turns on the optical fiber amplifier. When turning on the optical fiber amplifier, the first-stage gain unit is first turned on through the first gain control loop, and the output optical power of the first-stage gain unit is collected. If the output optical power of the first-stage gain unit is greater than the threshold optical power, the second-stage gain unit is turned on through the second gain control loop. The specific forms of the DAC and ADC are consistent with the existing technology.

[0066] During the operation of the high-power fiber amplifier, the MCU collects the input optical power and the switching signal of the high-power fiber amplifier. When the input optical power is lower than the shutdown threshold and / or the switching signal is at an invalid level, the second-stage gain unit is first shut down through the second gain control loop, and then the first-stage gain unit is shut down through the first gain control loop.

[0067] Furthermore, in this embodiment, the first-stage gain unit includes a first photodetector 23 (PD1), a fourth photodetector 28 (PD4), a first pump source 24 (PUMP1) and a second pump source 27 (PUMP2);

[0068] like Figure 2 As shown, the first-stage gain unit further includes an input signal port 1, a first optical splitter 2, a first isolator 3, a first wavelength division multiplexer 4, a first section of erbium-doped fiber 5, a second wavelength division multiplexer 6, a first IGFF unit 7, a third wavelength division multiplexer 8, a second section of erbium-doped fiber 9, a second IGFF unit 10, a second optical splitter 11, a variable attenuator 12, a third optical splitter 13, a fourth wavelength division multiplexer 14, a third section of erbium-doped fiber 15, a second isolator 16, a fourth optical splitter 17, a second photodetector 25, and a third photodetector 26, wherein:

[0069] The input signal port 1 is connected to the input end of the first optical splitter 2, the first optical splitting end of the first optical splitter 2 is connected to the input end of the first isolator 3, the second optical splitting end of the first optical splitter 2 is connected to the first photodetector 23, the output end of the first isolator 3 is connected to the first input end of the first wavelength division multiplexer 4, the first pump source 24 is connected to the second input end of the first wavelength division multiplexer 4, the output end of the first wavelength division multiplexer 4 is connected to the input end of the second wavelength division multiplexer 6 through the first section of erbium-doped optical fiber 5, the first output end of the second wavelength division multiplexer 6 is connected to the first input end of the third wavelength division multiplexer 8, and the second output end of the second wavelength division multiplexer 6 is connected to the second input end of the third wavelength division multiplexer 8 through the first IGFF unit 7. The output end of the third wavelength division multiplexer 8 is connected to the input end of the second IGFF unit 10 through the second section of erbium-doped optical fiber 9. The output end of the second IGFF unit 10 is connected to the input end of the second optical splitter 11. The first optical splitting end of the second optical splitter 11 is connected to the input end of the variable attenuator 12. The second optical splitting end of the second optical splitter 11 is connected to the second photodetector 25. The output end of the variable attenuator 12 is connected to the input end of the third optical splitter 13. The first optical splitting end of the third optical splitter 13 is connected to the first input end of the fourth wavelength division multiplexer 14. The second optical splitting end of the third optical splitter 13 is connected to the third photodetector. The second input end of the fourth wavelength division multiplexer 14 is connected to the second pump source 27. The output end of the fourth wavelength division multiplexer 14 is connected to the input end of the second isolator 16 through the third section of erbium-doped optical fiber 15. The output end of the second isolator 16 is connected to the input end of the fourth optical splitter 17. The first optical splitting end of the fourth optical splitter 17 is connected to the fourth photodetector 28.

[0070] Furthermore, the second-stage gain unit includes a multimode pump combiner 18, a first section of erbium-ytterbium co-doped fiber 19, a third isolator 20, a fifth optical splitter 21, an output signal port 22, a first multimode pump source 29 (MP1), a second multimode pump source 30 (MP2), and a fifth photodetector 31 (PD5);

[0071] The second splitting end of the fourth optical splitter 17 is connected to the first input end of the multimode pump combiner 18, the first multimode pump source 29 is connected to the second input end of the multimode pump combiner 18, the second multimode pump source 30 is connected to the third input end of the multimode pump combiner 18, the output end of the multimode pump combiner 18 is connected to the input end of the third isolator 20 through the first section of erbium-ytterbium co-doped optical fiber 19, the output end of the third isolator 20 is connected to the input end of the fifth optical splitter 21, the first splitting end of the fifth optical splitter 21 is connected to the output signal port 22, and the second splitting end of the fifth optical splitter 21 is connected to the fifth photodetector 31.

[0072] Furthermore, the control system includes a first linear amplification module (OPA1), the first gain control loop includes a first PID control module (PID&Pump control1), a first current-voltage conversion module (Current Mirror&LogConverter1), a second current-voltage conversion module (Current Mirror&Log Converter2) and a second linear amplification module (OPA2), and the first linear amplification module can be regarded as part of the first gain control loop or as part of the second gain control loop.

[0073] Specifically, the input end of the first current-voltage conversion module is connected to the negative electrode of the first photodetector 23, the input end of the first linear amplification module is connected to the positive electrode of the first photodetector 23, the output end of the first current-voltage conversion module is connected to the ADC, and the output end of the first linear amplification module is connected to the first input end of the first PID control module;

[0074] The input end of the second linear amplification module is connected to the positive electrode of the fourth photodetector 28, and the output end of the second linear amplification module is connected to the second input end of the first PID control module;

[0075] The input end of the second current-voltage conversion module is connected to the negative electrode of the fourth photodetector 28, and the output end of the second current-voltage conversion module is connected to the ADC;

[0076] A first output end of the first PID control module is connected to a first pump source 24 , and a second output end of the first PID control module is connected to a second pump source 27 .

[0077] Furthermore, the first linear amplification module is used to generate a first voltage signal according to the input optical signal of the high-power optical fiber amplifier, and the first current-voltage conversion module is used to generate a second voltage signal according to the input optical signal of the high-power optical fiber amplifier;

[0078] The second linear amplification module is used to generate a third voltage signal according to the output optical signal of the first-stage gain unit, and the second current-voltage conversion module is used to generate a fourth voltage signal according to the output optical signal of the first-stage gain unit.

[0079] In one embodiment of the present invention, the current-to-voltage conversion module includes a current mirror circuit and a logarithmic amplifier circuit. The first photodetector 23 detects the input optical signal of the optical fiber amplifier and converts the input optical signal into a first current signal. The first linear amplification module converts and linearly amplifies the first current signal into a first voltage signal (InputCtrl). The first voltage signal is input to the first input end of the first PID control module. The current mirror circuit in the first current-to-voltage conversion module copies the first current signal at a 1:1 ratio and transmits it to the logarithmic amplifier circuit. The logarithmic amplifier circuit converts the copied current signal into a second voltage signal (Input log ADC). The second voltage signal is logarithmically related to the first current signal, and the second voltage signal is input to the ADC.

[0080] The fourth photodetector 28 detects the output optical signal of the first gain unit of the optical fiber amplifier and converts the output optical signal of the first gain unit into a second current signal. The second linear amplification module converts and linearly amplifies the second current signal into a third voltage signal (Mid Output Ctrl). The third voltage signal is input to the second input end of the first PID control module. The current mirror circuit in the second current-voltage conversion module copies the second current signal at a 1:1 ratio and transmits it to the logarithmic amplifier circuit. The logarithmic amplifier circuit converts the copied current signal into a fourth voltage signal (Mid Output log ADC). The fourth voltage signal is logarithmically related to the second current signal. The fourth voltage signal is input to the ADC.

[0081] Furthermore, the second gain control loop includes a second PID control module (PID&Pump control2), a third current-voltage conversion module (Current Mirror&Log Converter3) and a third linear amplification module (OPA3);

[0082] The input end of the third current-voltage conversion module is connected to the negative electrode of the fifth photodetector 31, and the input end of the third linear amplification module is connected to the positive electrode of the fifth photodetector 31;

[0083] The output end of the third current-voltage conversion module is connected to the ADC, the output end of the third linear amplification module is connected to the first input end of the second PID control module, and the output end of the first linear amplification module is connected to the second input end of the second PID control module;

[0084] The third linear amplification module is used to generate a fifth voltage signal according to the output optical signal of the second-stage gain unit, and the third current-voltage conversion module is used to generate a sixth voltage signal according to the output optical signal of the second-stage gain unit;

[0085] A first output end of the second PID control module is connected to the first multi-mode pump source 29 , and a second output end of the second PID control module is connected to the second multi-mode pump source 30 .

[0086] The fifth photodetector 31 detects the output optical signal of the second gain unit of the optical fiber amplifier and converts the output optical signal of the second gain unit into a third current signal. The second linear amplification module converts and linearly amplifies the third current signal into a fifth voltage signal (Output Ctrl), which is input to the first input of the third PID control module. The current mirror circuit in the third current-to-voltage conversion module replicates the third current signal at a 1:1 ratio and transmits it to the logarithmic amplifier circuit. The logarithmic amplifier circuit converts the replicated current signal into a sixth voltage signal (Output log ADC), which is logarithmically related to the third current signal and is input to the ADC. The first voltage signal is also input to the second input of the second PID control module. The PID control module includes a PID controller and a pump source drive circuit. The MCU is connected to the PID controllers in the first and second PID control modules, respectively. The input of the DAC is connected to the MCU, and the output of the DAC is connected to the PID controllers in the first and second PID control modules, respectively. The current mirror circuit, logarithmic amplifier circuit, and linear amplification module can all adopt commonly used methods in the art.

[0087] In a specific implementation, the MCU receives a switch signal through a connector. When the switch signal is a valid signal, the MCU enables the first PID control module, and the first gain control loop controls the first-stage gain unit to start operating. The first PID control module performs PID control on the output optical power of the first-stage gain unit. In one possible implementation, the MCU inputs a digital signal corresponding to the first target gain signal to the DAC. The DAC converts the digital signal into the first target gain signal in the form of an analog signal and inputs it to the PID controller in the first PID control module. The PID controller in the first PID control module uses the first pump drive signal as the control variable, the sum of the first voltage signal and the first target gain signal as the target variable, and the third voltage signal as the feedback variable. PID control is performed based on the first voltage signal, the third voltage signal, and the first target gain signal to generate the first pump drive signal. The pump source drive circuit in the first PID control module controls the drive current of the first pump source 24 and the second pump source 27 based on the first pump drive signal to stabilize the output optical power of the first gain unit at the first target optical power. The PID controller and pump source drive circuit can be commonly used in the art, and the PID controller can perform PID control in a manner consistent with the prior art.

[0088] The first voltage signal (Input log ADC) is converted by the ADC into a digital signal and input into the MCU. The MCU calculates the input optical power based on the converted digital signal and compares the input optical power with the threshold optical power. When the input optical power is greater than the threshold optical power, the MCU enables the second PID control module, and the second gain control loop controls the second-stage gain unit to start working. The second PID control module performs PID control on the output optical power of the second-stage gain unit. In one possible implementation, the MCU inputs a second target gain signal to the PID controller in the second PID control module via the DAC. The PID controller in the second PID control module uses the second pump drive signal as the control variable, the sum of the first voltage signal and the first target gain signal as the target variable, and the fifth voltage signal as the feedback variable. PID control is performed based on the first voltage signal, the fifth voltage signal, and the second target gain signal to generate a second pump drive signal. The pump source drive circuit in the second PID control module controls the drive current of the first multimode pump source 29 and the second multimode pump source 30 based on the second pump drive signal, so that the output optical power of the second-stage gain unit is stabilized at the second target optical power.

[0089] When the MCU detects that the switch signal has become invalid and / or the input optical power is less than the shutdown threshold, it sequentially disables the second PID control module and the first PID control module, thereby shutting down the second-stage gain unit and the first-stage gain unit to ensure optical path safety. The specific method for enabling the first and second PID control modules by the MCU can be consistent with the existing technology.

[0090] Furthermore, the control system further includes a power management module and a power failure detection module;

[0091] The power supply is connected to the power management module through the connector, and the power management module is used to supply power to the control module, the power failure detection module, the first gain control loop, the second gain control loop, the first-stage gain unit, and the second-stage gain unit;

[0092] The power management module includes a first DC-DC conversion circuit, which is used to convert the power supply voltage into the required voltage of the first multi-mode pump source 29 and the second multi-mode pump source 30, and supply power to the first multi-mode pump source 29 and the second multi-mode pump source 30;

[0093] When the power failure detection module detects that the power supply is powered off, it controls the first DC-DC conversion circuit to stop supplying power to the first multi-mode pump source 29 and the second multi-mode pump source 30, so as to shut down the second-stage gain unit;

[0094] The power failure detection module includes a voltage comparator U1, a capacitor C1, a resistor R1, a resistor R2, a resistor R3 and a resistor R4, wherein:

[0095] The non-inverting input terminal of the voltage comparator U1 is connected to one end of the resistor R1 and one end of the resistor R2, the other end of the resistor R1 is connected to the power supply, and the other end of the resistor R2 is connected to the analog ground;

[0096] The inverting input terminal of the voltage comparator U1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the reference voltage source, and the output terminal of the voltage comparator U1 is connected to the enable terminal of the second DC-DC conversion circuit through the resistor R4;

[0097] One end of the capacitor C1 is connected to the power supply terminal of the voltage comparator U1 , and the other end of the capacitor C1 is connected to the ground terminal of the voltage comparator U1 .

[0098] Specifically, the power management module also includes multiple DC-DC conversion circuits, each used to convert the power supply voltage into the voltage required by the power supply target. The power supply targets are the components in the control module, power failure detection module, first gain control loop, second gain control loop, first-stage gain unit, and second-stage gain unit. Different power supply targets require different voltage specifications, and therefore require the use of corresponding DC-DC conversion circuits with different specifications for power supply. For example, to reduce power consumption, the first pump source 24 and the second pump source 27 are designed with a lower drive voltage to reduce power consumption of the driving power tube and reduce heat energy generation. The first multi-mode pump source 29 and the second multi-mode pump source 30 have a higher drive current, and further reduce the power consumption of the driving power tube, so their drive voltage needs to be lower.

[0099] In this embodiment, the first DC-DC conversion circuit (DC-to-DC converter) is a DC-DC chip (U2). Figure 3 Also shown is the peripheral circuit of the DC-DC chip, including capacitor C2, capacitor C3, capacitor C4, capacitor C5, inductor L1, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10 and resistor R11. The model of the DC-DC chip can be selected according to actual needs.

[0100] The ILMT pin of the DC-DC chip is grounded via resistor R6. The enable pin of the DC-DC chip, i.e., the enable terminal, is connected to the power supply via resistor R5. The VCC pin is connected to one end of capacitor C2. The PG pin is connected to one end of capacitor C2 via resistor R7. The other end of capacitor C2 is grounded. The VIN pin is connected to the power supply. The BS pin is connected to the LX pin via capacitor C3. The LX pin is connected to inductor L1. One end of resistors R8, R9, and R10 is connected to the FBS pin. The other end of resistor R8 is connected to one end of capacitor C4. The other end of resistor R9 is connected to the GNDS pin via resistor R11. The other end of resistor R10 and the other end of capacitor C4 form an output terminal connected to the first multi-mode pump source 29 and the second multi-mode pump source 30. The MODE pin is grounded via resistor R12. The SS pin is grounded via capacitor C5.

[0101] In this embodiment, in the power-off detection module, the voltage comparator U1 uses a precision voltage comparator with an open-drain output. The power supply voltage is 5V. The inverting input terminal of U1 is connected to a 2.5V reference voltage source. Resistors R1 and R2 form a voltage divider circuit to divide the power supply voltage. The output signal of the voltage comparator U1 is input to the enable pin (EN) of the DC-DC chip through resistor R4.

[0102] The specific working principle of the power-off detection module is as follows: when the power supply voltage is normally supplied, the voltage at the positive input terminal (IN+) of the voltage comparator U1 is greater than the voltage at the negative input terminal (IN-), and the output of the voltage comparator U1 is an open-drain output, which has no effect on the enable pin (EN) of the DC-DC chip U2. The DC-DC chip U2 operates normally and supplies power to the first multi-mode pump source 29 and the second multi-mode pump source 30 normally.

[0103] When a power outage occurs, the power supply voltage drops, and the voltage at the non-inverting input (IN+) of voltage comparator U1 is less than the voltage at the inverting input (IN-). The output of voltage comparator U1 is low, which in turn pulls the enable pin of DC-DC chip U2 low. DC-DC chip U2 stops outputting voltage, and the first and second multi-mode pump sources 29 and 30 powered by it naturally shut down. At this point, the power supply voltage has not yet been fully depleted, so the single-mode pump sources in the first-stage gain unit, namely, first and second pump sources 24 and 27, are still driving current, and the first-stage gain unit is still outputting signal light. As the power gradually depletes, the first-stage gain unit naturally shuts down, ensuring that the second-stage gain unit shuts down before the first-stage gain unit during a power outage. This prevents the second-stage gain unit from driving the multi-mode pump with high current, which could cause a large ASE signal to burn out optical components due to the absence of signal light.

[0104] It should be noted that the terms "first," "second," "third," etc. used in the above description are for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the scope of protection of the present invention.

Claims

1. A control method for a high-power optical fiber amplifier, characterized in that: The high-power optical fiber amplifier comprises a first-stage gain unit and a second-stage gain unit sequentially arranged along the transmission direction of light; The control method of the high-power optical fiber amplifier comprises: The high-power fiber amplifier is turned on in the order of first turning on the first-stage gain unit and then turning on the second-stage gain unit; The high-power optical fiber amplifier is shut down in the order of shutting down the second-stage gain unit first and then shutting down the first-stage gain unit.

2. The control method of a high-power optical fiber amplifier according to claim 1, characterized in that: Providing a switch signal for controlling the working state of the optical fiber amplifier, and turning on the optical fiber amplifier when the switch signal is at a valid level; When the optical fiber amplifier is turned on, the first-stage gain unit is controlled to be turned on first, and the output optical power of the first-stage gain unit is collected. When the output optical power of the first-stage gain unit reaches the threshold optical power, the second-stage gain unit is controlled to be turned on.

3. The control method of a high-power optical fiber amplifier according to claim 2, characterized in that: During the operation of the high-power fiber amplifier, the input optical power and the switch signal of the high-power fiber amplifier are collected. When the input optical power is lower than the shutdown threshold and / or the switch signal is at an invalid level, the second-stage gain unit and the first-stage gain unit are sequentially shut down.

4. The control method of a high-power optical fiber amplifier according to claim 1, wherein: Providing a power management module, the power management module is connected to a power supply, and the power management module is used to supply power to the first-stage gain unit and the second-stage gain unit; During the operation of the high-power optical fiber amplifier, a power failure detection is performed on the power supply, and when the power failure is detected, the power management module is controlled to stop supplying power to the second-stage gain unit, so as to shut down the second-stage gain unit.

5. A control system for a high-power optical fiber amplifier, characterized in that: Used to execute the control method of the high-power optical fiber amplifier according to any one of claims 1 to 4; The control system of the high-power optical fiber amplifier includes an adaptively connected control module, a first gain control loop and a second gain control loop, wherein the first gain control loop is connected to the first-stage gain unit, and the second gain control loop is connected to the second-stage gain unit; When the optical fiber amplifier is turned on, the control module controls the first-stage gain unit to be turned on through the first gain control loop. The first gain control loop collects the output optical power of the first-stage gain unit and transmits it to the control module. When the output optical power of the first-stage gain unit is greater than the threshold optical power, the control module controls the second-stage gain unit to be turned on through the second gain control loop. When the optical fiber amplifier is turned off, the control module first controls the second-stage gain unit to be turned off through the second gain control loop, and then controls the first-stage gain unit to be turned off through the first gain control loop.

6. The control system of the high-power optical fiber amplifier according to claim 5, characterized in that: The control module receives a switch signal for controlling the switch state of the high-power optical fiber amplifier, and the control module collects input optical power through a first gain control loop; The control module turns on the high-power fiber amplifier when the switch signal is at a valid level, and turns off the high-power fiber amplifier when the input optical power is lower than a shutdown threshold and / or the switch signal is at an invalid level.

7. The control system of the high-power optical fiber amplifier according to claim 5, characterized in that: The first-stage gain unit includes a first photodetector, a fourth photodetector, a first pump source, and a second pump source; The control system includes a first linear amplification module, the control module includes an MCU, a DAC and an ADC; the first gain control loop includes a first PID control module, a first current-voltage conversion module, a second current-voltage conversion module and a second linear amplification module; The input end of the first current-voltage conversion module is connected to the negative electrode of the first photodetector, the input end of the first linear amplification module is connected to the positive electrode of the first photodetector, the output end of the first current-voltage conversion module is connected to the ADC, and the output end of the first linear amplification module is connected to the first input end of the first PID control module; The input end of the second linear amplification module is connected to the positive electrode of the fourth photodetector, and the output end of the second linear amplification module is connected to the second input end of the first PID control module; The input end of the second current-voltage conversion module is connected to the negative electrode of the fourth photodetector, and the output end of the second current-voltage conversion module is connected to the ADC; The first output end of the first PID control module is connected to the first pump source, and the second output end of the first PID control module is connected to the second pump source.

8. The control system of the high-power optical fiber amplifier according to claim 7, characterized in that: The first linear amplification module is used to generate a first voltage signal according to the input optical signal of the high-power optical fiber amplifier, and the first current-voltage conversion module is used to generate a second voltage signal according to the input optical signal of the high-power optical fiber amplifier; The second linear amplification module is used to generate a third voltage signal according to the output optical signal of the first-stage gain unit, and the second current-voltage conversion module is used to generate a fourth voltage signal according to the output optical signal of the first-stage gain unit.

9. The control system of the high-power optical fiber amplifier according to claim 7, characterized in that: The second-stage gain unit includes a fifth photodetector, a first multi-mode pump source, and a second multi-mode pump source; The second gain control loop includes a second PID control module, a third current-voltage conversion module and a third linear amplification module; The input end of the third current-voltage conversion module is connected to the negative electrode of the fifth photodetector, and the input end of the third linear amplification module is connected to the positive electrode of the fifth photodetector; The output end of the third current-voltage conversion module is connected to the ADC, the output end of the third linear amplification module is connected to the first input end of the second PID control module, and the output end of the first linear amplification module is also connected to the second input end of the second PID control module; The third linear amplification module is used to generate a fifth voltage signal according to the output optical signal of the second-stage gain unit, and the third current-voltage conversion module is used to generate a sixth voltage signal according to the output optical signal of the second-stage gain unit; A first output end of the second PID control module is connected to a first multi-mode pump source, and a second output end of the second PID control module is connected to a second multi-mode pump source.

10. The control system of the high-power optical fiber amplifier according to claim 9, characterized in that: It also includes a connector, a power management module and a power failure detection module; The power supply is connected to the power management module through the connector, and the power management module is used to supply power to the control module, the power failure detection module, the first gain control loop, the second gain control loop, the first-stage gain unit, and the second-stage gain unit; The power management module includes a first DC-DC conversion circuit, which is used to convert the power supply voltage into the operating voltage required by the first multi-mode pump source and the second multi-mode pump source, and supply power to the first multi-mode pump source and the second multi-mode pump source; When the power failure detection module detects that the power supply is powered off, the first DC-DC conversion circuit is controlled to stop supplying power to the first multi-mode pump source and the second multi-mode pump source, so as to shut down the second-stage gain unit; The power failure detection module includes a voltage comparator U1, a capacitor C1, a resistor R1, a resistor R2, a resistor R3 and a resistor R4, wherein: The non-inverting input terminal of the voltage comparator U1 is connected to one end of the resistor R1 and one end of the resistor R2, the other end of the resistor R1 is connected to the power supply, and the other end of the resistor R2 is connected to the analog ground; The inverting input terminal of the voltage comparator U1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the reference voltage source, and the output terminal of the voltage comparator U1 is connected to the enable terminal of the first DC-DC conversion circuit through the resistor R4; One end of the capacitor C1 is connected to the power supply terminal of the voltage comparator U1 , and the other end of the capacitor C1 is connected to the ground terminal of the voltage comparator U1 .

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