A method and device for controlling a pump source of a fiber amplifier, and a laser radar

Abstract

The present application provides a control method, device and lidar for a pump source of an optical fiber amplifier. The method includes: obtaining the initial input power of the input light of the optical fiber amplifier and the working current of the pump source; if the initial input power is less than or equal to a preset input power threshold, controlling the working mode of the pump source to switch from the first control mode to the second control mode, and maintaining the second control mode within a preset delay time T0; sampling the input light of the optical fiber amplifier N times at a preset interval time ΔT, and obtaining the corresponding first input power to the Nth input power; where N - 1 < m ≦ N, m = T0 / ΔT, and N is a positive integer; based on the relationship between the first input power to the Nth input power and the preset input power threshold. The above working method for controlling the pump source can match the working characteristics of the laser being periodically opened and closed, and extend the service life of the pump source.

Description

Technical Field

[0001] This application belongs to the field of lidar detection technology, and particularly relates to a control method, device and lidar for an optical fiber amplifier pump source. Background Technology

[0002] LiDAR is currently widely used in intelligent transportation, autonomous driving, driver assistance, navigation, surveying and mapping, meteorology, aerospace, robotics, and other fields. In LiDAR systems that use rotating mirrors for scanning, when the probe light is incident on a non-flat reflective surface, it will be reflected and scattered at the edges, deviating from the designed optical path direction. These reflected or scattered unintended light rays, after propagating within the LiDAR, will interfere with normal reception, affecting the LiDAR's ranging capability and accuracy. Summary of the Invention

[0003] This application provides a method, apparatus, and lidar for controlling the pump source of an optical fiber amplifier, which solves the problem that optical fiber amplifiers have difficulty responding to changes in input light to operate normally.

[0004] In a first aspect, embodiments of this application provide a method for controlling a pump source of an optical fiber amplifier, applied to an optical fiber amplifier, comprising:

[0005] Obtain the initial input power of the input light of the fiber amplifier and the operating current of the pump source;

[0006] If the initial input power is less than or equal to a preset input power threshold, the pump source's operating mode is controlled to switch from a first control mode to a second control mode, and the second control mode is maintained within a preset delay time T0.

[0007] The input light of the fiber amplifier is subjected to a preset interval time. Perform N samplings and obtain the corresponding first input power to the Nth input power; where N-1 <m≦N,m= T0 / N is a positive integer;

[0008] The working state of the pump source is controlled based on the relationship between the first input power to the Nth input power and the preset input power threshold.

[0009] In one embodiment, controlling the operating state of the pump source based on the relationship between the first input power to the Nth input power and the preset input power threshold includes:

[0010] If all input powers from the first input power to the Nth input power are less than or equal to the preset input power threshold, the pump source is controlled to be turned off.

[0011] If the first input power to the (N - 1)th input power are all less than or equal to the preset input power threshold, and the Nth input power is greater than the preset input power threshold, control the operating mode of the pump source to be switched from the second control mode to the first control mode.

[0012] In one embodiment, the range of the preset delay time T0 is:

[0013] T1 < T0, where T1 is the time when there is no input light to the fiber amplifier.

[0014] In one embodiment, the preset interval time is in the range of:

[0015] ΔT < T1, where T1 is the time when there is no input light to the fiber amplifier.

[0016] In one embodiment, the first control mode is a power automatic control mode, and the pump source in the power automatic control mode keeps the output power of the fiber amplifier constant; the second control mode is a current automatic control mode, and the pump source in the current automatic control mode keeps a constant operating current.

[0017] In one embodiment, the constant operating current maintained by the pump source is the operating current of the pump source in the first control mode before the operating mode conversion.

[0018] In one embodiment, the output power P range of the pump source is: P ≧ 10W.

[0019] In a second aspect, an embodiment of the present application provides a control device for a pump source of a fiber amplifier, which is applied to a fiber amplifier and includes:

[0020] An acquisition module, configured to acquire the initial input power of the input light of the fiber amplifier and the operating current of the pump source;

[0021] A first judgment and control module, configured to, if the initial input power is less than or equal to a preset input power threshold, control the operating mode of the pump source to be switched from the first control mode to the second control mode, and maintain the second control mode within a preset delay time T0;

[0022] A sampling module, configured to sample the input light of the fiber amplifier at a preset interval time for N times, and obtain the corresponding first input power to the Nth input power; where N - 1 < m ≦ N, m = T0 / , and N is a positive integer;

[0023] The second judgment and control module is used to control the working state of the pump source based on the relationship between the first input power to the Nth input power and the preset input power threshold.

[0024] Thirdly, embodiments of this application provide a lidar, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor loads and executes the computer program to implement the above-described control method.

[0025] The beneficial effects of the embodiments in this application compared with the prior art are:

[0026] For the fiber amplifier, the initial input power of the input light and the operating current of the pump source are obtained. If the initial input power is less than or equal to a preset input power threshold, the laser has stopped emitting. To prevent the pump source from shutting down or increasing as the input power decreases, the operating mode of the pump source is switched from the first control mode to the second control mode, and this second control mode is maintained for a preset delay time T0. The input light to the fiber amplifier is then switched at preset intervals. N samples are taken to obtain the corresponding first to Nth input powers. The sampling times of the first (N-1) samples are within a preset delay time T0, and the sampling time of the Nth sample is after the end of the preset delay time T0. That is, the input power of the input light is continuously monitored periodically until the sampling time exceeds the end of the preset delay time. Based on the relationship between the first to Nth input powers and the preset input power threshold, the working state of the pump source is controlled. If the input power of the input light remains less than or equal to the preset input power threshold, it means that the laser is still not emitting, and the pump source of the fiber amplifier can be turned off. If the input power of the input light returns to normal, it means that the laser has started emitting after periodic shutdown, and the working state of the pump source needs to be adjusted to stabilize the output power of the fiber amplifier. This pump source control method can match the periodic switching characteristics of the laser. The change period of the probe light after amplification by the fiber amplifier is consistent with the change period of the probe light emitted by the laser, ensuring the power stability of the fiber amplifier in the output stage. It can also avoid the pump source frequently switching on and off with the periodic changes of the input light, thus extending the service life of the pump source.

[0027] It is understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant descriptions in the first aspect above, and will not be repeated here. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a lidar provided in one embodiment of this application;

[0030] Figure 2 This is a schematic diagram of the structure of an optical fiber amplifier provided in one embodiment of this application;

[0031] Figure 3 This is a schematic flowchart of a pump source control method provided in an embodiment of this application;

[0032] Figure 4 This is a schematic diagram of an optical fiber amplifier amplifying input and output light according to an embodiment of this application;

[0033] Figure 5 This is a schematic diagram of the structure of a control module for a pump source provided in one embodiment of this application. Detailed Implementation

[0034] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, modules, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0035] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0036] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0037] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0039] This application provides a lidar system including a transmitting module, a receiving module, and a scanning module. For example... Figure 1 As shown, the transmitting module is used to emit a probe light and direct it toward the scanning module; the scanning module is used to deflect the probe light to scan the field of view to be measured; the scanning module is also used to receive the echo light returned from the coaxial cable and deflect the echo light before directing it toward the receiving module; the receiving module is used to receive the echo light and perform reception processing.

[0040] In lidar systems employing rotating mirrors in their scanning modules, the probe light emitted by the transmitting module strikes the surface of the rotating mirror and is reflected back to the outside of the lidar, used to detect targets and scan the target field of view. The rotating mirror is typically a multi-faceted mirror with more than one reflective surface. This multi-faceted mirror contains the same number of edges as its surfaces and rotates continuously along its central axis at a certain speed during operation. During operation, the probe light inevitably strikes the edges of the multi-faceted mirror, where it is scattered and enters the lidar's interior. Due to the high power of the probe light, this scattered light undergoes multiple reflections within the lidar, affecting other optical components and even interfering with the receiving module, thus impacting the lidar's ranging capability and accuracy. Therefore, it is necessary to suppress unwanted light scattered into the lidar and control the periodic opening and closing of the transmitting module. When the probe light is about to hit the edge of the rotating mirror, the transmitting module adjusts to the off state and stops emitting the probe light. The transmitting module remains off for a period of time until the edge of the rotating mirror has rotated past. When the probe light hits the reflective surface of the rotating mirror, the transmitting module adjusts to the on state and emits the probe light. The transmitting module remains on for a period of time until the probe light laser hits the next edge of the rotating mirror. The duration of the opening and closing of the transmitting module is related to the rotation speed of the multi-faceted rotating mirror.

[0041] To improve the ranging capability of the lidar, a fiber optic amplifier is installed within the transmitting module to amplify the detection light emitted by the laser, increasing its power. The transmitting module includes a laser and a fiber optic amplifier. The detection light emitted by the laser enters the fiber optic amplifier, which amplifies the power of the detection light before outputting the amplified detection light. This amplified light is then directed towards a multi-faceted rotating mirror for scanning. The laser can achieve rapid on / off switching within microseconds. To enable the periodic on / off switching of the transmitting module, the fiber optic amplifier needs to achieve a certain level of... Figure 4 The function shown ensures that the variation period of the probe light after amplification by the fiber optic amplifier matches the variation period of the probe light emitted by the laser. Specifically, the laser's emission power in the on state is Pi, the on state duration in one cycle is T1, and the off state duration is T2. After power amplification by the fiber optic amplifier, the on state duration in one cycle is T1, the output probe light power in the on state is P0, and the off state duration is T2.

[0042] The internal structure of the fiber optic amplifier is as follows Figure 2 As shown, the fiber amplifier includes an input end, a combiner, a pump source, a gain fiber, and an output end. The probe light emitted by the laser serves as the input light, entering the fiber amplifier through its input end. The pump light emitted from the pump source and the input light are combined by the combiner. The combined light enters the gain fiber, where the pump light undergoes population inversion and is gradually consumed, while the input light is amplified due to stimulated emission. After being amplified by the gain fiber, the input light becomes the output light, which is output from the fiber amplifier's output end. The output light is the amplified probe light.

[0043] The fiber optic amplifier's input end is equipped with a first beam splitter and an input detector (PD). The input light is split into two beams by the first beam splitter; a small portion enters the input PD to detect the input light power, while the majority enters the combiner. The fiber optic amplifier's output end is equipped with a second beam splitter and an output PD. The output light is split into two beams by the second beam splitter; a small portion enters the output PD to detect the output light power, while the majority is output from the output end. The input and output PDs convert the detected optical power into electrical signals, which are then converted into digital quantities by analog-to-digital (A / D) converters and sent to the microprocessor for processing. The microprocessor is the core device for control; in addition to monitoring the input and output light power, it can also control the drive current of the pump source to ensure stable output light power of the fiber optic amplifier.

[0044] To protect the pump source, fiber amplifiers typically include a function to shut down the pump when no input light is detected. That is, when the input PD detects no input light or the input light power is below a certain set value, the microprocessor inside the fiber amplifier controls the pump source to shut down. Therefore, when the laser periodically turns on and off, the probe light input to the fiber amplifier also changes periodically, causing the fiber amplifier to periodically switch the pump source on and off. However, the switching time of the pump source is much longer than the period of the input light switching, making it impossible to output probe light with the same periodic changes.

[0045] The fiber amplifier can be at least one of erbium-doped fiber amplifier (EDFA), praseodymium-doped fiber amplifier (PDFA), and erbium-ytterbium co-doped fiber amplifier (EYDFA).

[0046] To address the issue that the output light cycle of the aforementioned fiber optic amplifier cannot match the input light cycle, such as... Figure 3 As shown in the figure, this application embodiment also provides a method for controlling the pump source of an optical fiber amplifier, including:

[0047] S100, obtains the initial input power of the input light of the fiber amplifier and the operating current of the pump source.

[0048] Obtaining the initial input power of the input light to the fiber optic amplifier reveals its input status. As mentioned earlier, the laser periodically switches on and off, and the probe light input to the fiber optic amplifier also changes periodically. Based on the input power, it can be determined whether there is input light at the current moment. The operating current of the pump source reveals its current operating status, which is the basis for subsequent pump source control.

[0049] It should be noted that the input light is split into two beams by the first beam splitter, namely the first input light and the second input light. The power of the first input light is much smaller than that of the second input light; for example, the power of the first input light is 2% of the total input light power. The first input light enters the input PD and is converted into an analog signal. Then, it passes through an analog-to-digital converter and a microprocessor to obtain the initial input power of the fiber amplifier. The second input light directly enters the beam combiner and, after amplification, becomes the output light. Furthermore, a first isolator is installed between the first beam splitter and the beam combiner to prevent unwanted light with the opposite propagation direction of the second input light from entering the first beam splitter, thereby affecting the operation of the first beam splitter and the detection results of the input PD.

[0050] In one embodiment, the output power range of the pump source is: P ≥ 10W, where P is the output power of the pump source. The greater the output power of the pump source, the greater the gain of the fiber amplifier.

[0051] S200, if the initial input power is less than or equal to the preset input power threshold, the operating mode of the pump source is switched from the first control mode to the second control mode, and the second control mode is maintained within the preset delay time T0.

[0052] After obtaining the initial input power of the input light of the fiber optic amplifier, it is compared with a preset input power threshold, which is set to be relatively small.

[0053] If the initial input power is greater than the preset input power threshold, it indicates that the laser is on, the input light is normal, and the fiber amplifier is also in normal working condition. At this time, the pump source is in the first control mode.

[0054] In one embodiment, to maintain a stable output light power of the fiber amplifier, the first control mode is Automatic Power Control (APC) mode. In APC mode, the pump light output from the pump source varies with the input light power, and the pump source in APC mode maintains a constant output power for the fiber amplifier. Since the ranging capability of a lidar is directly related to the power of the detection light, stable output light power of the fiber amplifier not only ensures the lidar's detection performance but also maintains the lidar's operational stability.

[0055] The output light is split into two beams by a second beam splitter, namely the first output light and the second output light. The power of the first output light is much smaller than that of the second output light, for example, 2% of the output light power. The first output light enters the output PD and is converted into an analog signal, then passes through an analog-to-digital converter and a microprocessor to obtain the output power of the output light. If the detected output power of the output light deviates from the target output power, the microprocessor adjusts the power of the pump light output from the pump source according to the deviation. Specifically, the microprocessor outputs a control signal to the pump source drive circuit based on the difference between the output power of the fiber amplifier's output light and the target output power. The pump source drive circuit adjusts the power of the pump light output from the pump source. When the output power of the output light is less than the target output power, the pump source is controlled to increase the pump light power; when the output power of the output light is greater than the target output power, the pump source is controlled to decrease the pump light power. In the automatic power control mode, the output power of the fiber amplifier is stabilized at the target output power (or the difference between the two is within a threshold range), thus keeping the output power of the fiber amplifier constant and reducing the power fluctuation of the lidar's detection light.

[0056] Furthermore, a second isolator is provided between the gain fiber and the second beam splitter to prevent unwanted light that is opposite to the direction of output light propagation from entering the gain fiber, thereby affecting the amplification effect of the gain fiber.

[0057] If the initial input power is greater than the preset input power threshold, it indicates that the laser is on, the input light is normal, and the fiber amplifier is also in normal working condition. At this time, the pump source is in the first control mode.

[0058] If the initial input power is less than or equal to the preset input power threshold, it indicates that the laser is in a closed state, there is no input light, or the laser is malfunctioning and the input light power is too low to meet the requirements. In this case, the output power of the fiber amplifier will drop sharply. The pump source is still in the first control mode. To ensure stable output power, the microprocessor will control the pump source to output maximum power, which will damage the pump source, reduce its lifespan, and prevent the fiber amplifier from outputting periodically changing probe light. To protect the pump source, the fiber amplifier has a function to shut down the pump source when no input light is detected. That is, when the input PD detects no input light or the input power of the input light is lower than a certain set value, the microprocessor inside the fiber amplifier will control the pump source to shut down. When there is no input light, the microprocessor controls the pump source to shut down, but when the input light returns to normal, the pump source cannot quickly respond and resume normal operation.

[0059] In one embodiment, when there is no input light or the input light is abnormal, the pump source's operating mode switches from a first control mode to a second control mode. The second control mode is Auto Current Control (ACC) mode, in which the pump source maintains a constant operating current. Therefore, the pump light output by the pump source does not change with the initial input power of the probe light, and the pump source continues to output pump light while maintaining a constant operating current. Since there is almost no probe light input at the input end of the fiber amplifier at this time, there is no energy output at the output end, or only a small amount of probe light output, which will not affect other optical components inside the lidar. Simultaneously, since the pump source maintains the second control mode for a preset delay time T0, frequent on / off switching of the pump source is avoided, extending the pump source's lifespan.

[0060] In one embodiment, the pump source maintains a constant operating current, which is the operating current of the pump source in the first control mode before the mode transition. The pump source directly uses the operating current of the first control mode as the operating current of the second control mode without further conversion, thus accelerating the switching speed of the operating mode, avoiding fluctuations in the pump source's operating current, and extending the pump source's lifespan. The constant operating current of the pump source can also be adjusted to a preset current value, simplifying the control logic and reducing the power consumption of the fiber amplifier.

[0061] In one embodiment, the range of the preset delay time is: T1 < T0, where T0 is the preset delay time and T1 is the time when there is no input light in the fiber amplifier. The transmitting module periodically transmits detection light. During the period when no detection light is transmitted, the detection light is avoided from hitting the edge of the polygon mirror. After the edge of the polygon mirror has rotated past, the transmitting module resumes transmitting detection light, which is directed towards the reflecting surface of the polygon mirror until the polygon mirror rotates to a position where the detection light is about to hit the next edge. As Figure 4 shown, in the period of the detection light transmitted by the transmitting module, the time when the transmitting module stops transmitting detection light is T1, and the time when the transmitting module transmits detection light is T2. Correspondingly, the time when the laser is turned off is T1 (i.e., the time when there is no input light in the fiber amplifier is T1), and the time when it is turned on is T2. At least during the time when there is no input light in the fiber amplifier, the pump source should be maintained in the ACC mode. If T0 ≤ T1, it is possible that when the input light of the fiber amplifier has not yet recovered to normal, the pump source switches back from the ACC mode to the APC mode. At this time, the pump source detects that there is no input light and still performs the pump-off operation, and it is still impossible to quickly turn on the pump source and operate in the APC mode when the input light is normal. The preset delay time being greater than the off time of the input light of the fiber amplifier avoids frequent opening and closing of the pump source and extends the life of the pump source.

[0062] S300, sample the input light of the fiber amplifier at a preset interval time for N times and obtain the corresponding first input power to the Nth input power.

[0063] When the pump source is maintained in the second control mode, monitor the situation of the input light of the fiber amplifier. Continuously sample the input light of the fiber amplifier at a preset interval time to obtain the input power of the input light and determine the current on / off state of the laser according to the input power.

[0064] Sample the input light of the fiber amplifier at a preset interval time for N times and obtain the corresponding first input power to the Nth input power. The sampling times of the first (N - 1) samplings are within the preset delay time T0, and the sampling time of the Nth sampling is after the end moment of the preset delay time T0, that is, continuously detect the input power of the input light regularly until the sampling time exceeds the end moment of the preset delay time. Therefore, the value of the sampling number N needs to satisfy: N - 1 < m ≦ N, m = T0 / ΔT, and N is a positive integer.

[0065] In one embodiment, the preset interval time ΔT is in the range of ΔT < T1. As mentioned above, the transmitting module periodically emits probe light, and the laser also periodically turns on and off. The laser is off for T1 (i.e., the time when the fiber amplifier has no input light is T1), and on for T2. After the pump source switches from APC mode to ACC mode, it maintains ACC mode for at least one sampling time to facilitate timely detection of the fiber amplifier's input light and determine the current on / off state of the laser. Based on the input power of the input light, the pump source's operating mode can be controlled or switched in a timely manner.

[0066] It should be noted that the first sampling can be performed based on a sampling command. Specifically, when the pump source's operating mode changes from the first control mode to the second control mode, the microprocessor sends a sampling command to the sampling module, which then performs the first sampling to obtain the first input power. Alternatively, when the laser's operating state switches from on to off, the laser's drive module sends a switching signal to the fiber amplifier's microprocessor, which then sends a sampling command to the sampling module, which performs the first sampling. This method of obtaining the timing of the first sampling allows for monitoring the input power of the input light when the pump source's operating mode changes or is about to change, facilitating timely acquisition of the input power and subsequent control of the pump source's operating mode. The first sampling can also be performed based on a clock signal. Specifically, the fiber amplifier includes a clock module that sends clock commands at fixed time intervals. The microprocessor, based on the received clock commands, sends a sampling command to the sampling module, which then performs sampling at a fixed period. The first sampling by the sampling module within a preset delay time T0 is the aforementioned first sampling. The fiber optic amplifier can also omit the clock module and directly use the LiDAR's clock module. The fiber optic amplifier's microprocessor obtains the clock signal directly from the LiDAR's clock module. This method, with fixed-period sampling, simplifies the control logic, reduces system design complexity, and allows for the reuse of functional modules within the LiDAR.

[0067] S400 controls the working state of the pump source based on the relationship between the first input power to the Nth input power and the preset input power threshold.

[0068] The pump source's operating state is controlled based on the relationship between the first to Nth input powers and a preset input power threshold. The pump source's operating mode is adjusted promptly according to changes in the input light's power, enabling the fiber amplifier to match the laser's periodic on / off characteristics. The variation period of the probe light amplified by the fiber amplifier matches the variation period of the probe light emitted by the laser, ensuring stable power output from the fiber amplifier and preventing frequent switching of the pump source due to periodic changes in the input light, thus extending the pump source's lifespan.

[0069] In one embodiment, controlling the operating state of the pump source based on the relationship between the first input power to the Nth input power and a preset input power threshold includes:

[0070] S410, if the first input power to the Nth input power are all less than or equal to the preset input power threshold, control the pump source to shut down.

[0071] As mentioned above, the sampling times of the first (N-1) samples are within the preset delay time T0, and the sampling time of the Nth sample is after the end of the preset delay time T0. This indicates that within the preset delay time T0, the laser is in a turned-off state, and the fiber amplifier has no input light (or the input power of the input light is less than the preset input power threshold). Since the sampling time of the Nth sample is after the end of the preset delay time T0, if the Nth input power obtained by the Nth sample is still less than or equal to the preset input power threshold, it means that the laser has not been properly turned on to resume emitting the probe light. At this time, the microprocessor controls the pump source to turn off, avoiding the frequent switching of the pump source caused by premature pump shutdown, which affects its lifespan, and also saving energy by turning off the pump source in a timely manner.

[0072] S420, if the first input power to the (N-1)th input power are all less than or equal to the preset input power threshold, and the Nth input power is greater than the preset input power threshold, the operating mode of the pump source is switched from the second control mode to the first control mode.

[0073] Within a preset delay time, if the first input power to the (N-1)th input power is less than or equal to a preset input power threshold, the laser is in a turned-off state, and the fiber amplifier has no input light (or the input power of the input light is less than the preset input power threshold). If the Nth input power is greater than the preset input power threshold, it indicates that the laser has been normally turned on and is outputting probe light when the Nth sampling is performed after the end of the preset delay time T0. To ensure that the probe light emitted by the laser can output a constant output power after being amplified by the fiber amplifier, the operating mode of the pump source is switched from the second control mode to the first control mode, i.e., from ACC mode to APC mode. According to the laser's duty cycle, it will be turned on again and emit probe light after a brief shutdown. During the brief shutdown of the laser, the pump source does not turn off but continues to output a constant current; when the laser is turned on again, the pump source does not need to be restarted but switches to APC mode and quickly adjusts the output power to ensure that the output power of the probe light output by the fiber amplifier meets the requirements. This method enables the fiber laser's response speed to keep up with the rapidly changing laser. The variation period of the probe light after amplification by the fiber amplifier is consistent with the variation period of the probe light emitted by the laser, ensuring the power stability of the fiber amplifier in the output stage. It also avoids the pump source from frequently switching on and off due to the periodic changes in the input light, thus extending the pump source's lifespan.

[0074] It should be noted that among the first input power to the (N - 1)th input power obtained, there may be several cases where the power is greater than the preset input power threshold. Exemplarily, when the jth input power is greater than the preset input power threshold, it may be that the laser is abnormal, resulting in abnormal power of the detection light emitted by the laser; it may also be that the system control of the lidar is abnormal, causing the laser to emit during the off period of its working cycle; it may also be that the input PD is abnormal, resulting in abnormal input power of the detected input light. Here, 1 ≤ j ≤ N - 1, and j is an integer. When the above situation occurs, the emission module can be made to send an alarm instruction upward, and the lidar cannot be used until the abnormality is excluded.

[0075] The beneficial effects of this embodiment compared with the prior art are as follows:

[0076] For an optical fiber amplifier, by obtaining the initial input power of the input optical signal of the optical fiber amplifier and the working current of the pump source; if the initial input power is less than or equal to the preset input power threshold; at this time, the laser has stopped emitting. To avoid the pump source from being turned off or increased as the input power decreases, the working mode of the pump source is controlled to be switched from the first control mode to the second control mode, and the second control mode is maintained within the preset delay time T0; within the preset delay time, the input optical signal of the optical fiber amplifier is sampled N times at a preset interval time ΔT, and the corresponding first input power to the Nth input power is obtained; the sampling times of the first (N - 1) samplings are within the preset delay time T0, and the sampling time of the Nth sampling is after the end time of the preset delay time T0, that is, the input power of the input optical signal is continuously detected regularly until the sampling time exceeds the end time of the preset delay time. Here, N - 1 < m ≦ N, where m is the ratio of the preset delay time to the preset interval time, and N is a positive integer and N ≥ 1. Based on the relationship between the first input power to the Nth input power and the preset input power threshold, the working state of the pump source is controlled. If the input power of the input optical signal remains less than or equal to the preset input power threshold, it means that the laser still remains stopped from emitting. At this time, the pump source of the optical fiber amplifier can be turned off; if the input power of the input optical signal returns to normal, it means that the laser starts to emit after periodic shutdown. At this time, the working state of the pump source needs to be adjusted to maintain the stability of the output optical power of the optical fiber amplifier. By using this control method for the pump source, it is possible to match the working characteristics of the periodic opening and closing of the laser. The change period of the detection light amplified by the optical fiber amplifier is consistent with the change period of the detection light emitted by the laser, ensuring the power stability of the optical fiber amplifier in the output stage, and also avoiding the pump source from being frequently switched on and off with the periodic change of the input light, improving the detection performance of the lidar, and at the same time avoiding the pump source from excessively outputting the maximum optical power, thus extending the service life of the pump source.

[0077] Second aspect, as Figure 5 As shown, this embodiment provides a control device for a fiber optic amplifier pump source, including:

[0078] The acquisition module 100 is used to acquire the initial input power of the input light of the fiber amplifier and the operating current of the pump source;

[0079] The first judgment control module 200 is used to control the working mode of the pump source to switch from the first control mode to the second control mode after acquiring the initial input power if the initial input power is less than or equal to a preset input power threshold, and to maintain the second control mode for a preset delay time T0.

[0080] The sampling module 300 is used to sample the input light of the fiber amplifier at preset intervals. Perform N samplings and obtain the corresponding first to Nth input powers, where N-1 <m≦N,m=T0 / N is a positive integer;

[0081] The second judgment and control module 400 is used to control the working state of the pump source based on the relationship between the first input power to the Nth input power and the preset input power threshold.

[0082] It should be noted that the information interaction and execution process between the above-mentioned devices / modules are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0083] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0084] Thirdly, embodiments of this application provide a lidar, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor loads and executes the computer program to implement the control method as described in any one of the first aspects above.

[0085] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program, characterized in that, when the computer program is executed by a processor, it implements the control method as described in any one of the first aspects above.

[0086] The pump source control method provided in this application embodiment can be applied to terminal devices such as mobile phones, tablets, wearable devices, vehicle-mounted devices, augmented reality (AR) / virtual reality (VR) devices, laptops, ultra-mobile personal computers (UMPCs), netbooks, and personal digital assistants (PDAs). This application embodiment does not impose any restrictions on the specific type of terminal device.

[0087] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms.

[0088] The computer-readable medium may include at least: any entity or device capable of carrying computer program code to a photographing device / terminal device, recording media, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media. Examples include USB flash drives, portable hard drives, magnetic disks, or optical discs.

[0089] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0090] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0091] In the embodiments provided in this application, it should be understood that the disclosed modules and methods can be implemented in other ways. For example, the module embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0092] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for controlling a pump source for an optical fiber amplifier, characterized in that, Including: Obtain the initial input power of the input light of the fiber amplifier and the working current of the pump source; If the initial input power is less than or equal to a preset input power threshold, determine that the laser is in a closed state or the laser is abnormal, control the working mode of the pump source to switch from the first control mode to the second control mode, and maintain the second control mode within a preset delay time T0; wherein, the first control mode is a power automatic control mode, and the pump source in the power automatic control mode makes the fiber amplifier maintain a constant output power; the second control mode is a current automatic control mode, and the pump source in the current automatic control mode maintains a constant working current; The input light of the fiber amplifier is subjected to a preset interval time. Perform N samplings and obtain the corresponding first input power to the Nth input power; where N-1 <m≦N,m= T0 / N is a positive integer; Based on the relationship between the first input power to the Nth input power and the preset input power threshold, control the working state of the pump source.

2. The control method as described in claim 1, characterized in that, The controlling the working state of the pump source based on the relationship between the first input power to the Nth input power and the preset input power threshold includes: If the first input power to the Nth input power are all less than or equal to the preset input power threshold, control the pump source to turn off; If the first input power to the (N - 1)th input power are all less than or equal to the preset input power threshold, and the Nth input power is greater than the preset input power threshold, control the working mode of the pump source to switch from the second control mode to the first control mode.

3. The control method as described in claim 1, characterized in that, The range of the preset delay time T0 is: T1 < T0, where T1 is the time when there is no input light in the fiber amplifier.

4. The control method as described in claim 1, characterized in that, The preset interval time The scope is: ΔT < T1, where T1 is the time when there is no input light in the fiber amplifier.

5. The control method as described in claim 1, characterized in that, The pump source maintains the constant working current, which is the working current of the pump source in the first control mode before the working mode conversion.

6. The control method according to claim 1, wherein The output power P of the pump source ranges as: P ≥ 10W.

7. A control device for a pump source of an optical fiber amplifier, characterized in that, Including: An acquisition module, configured to obtain the initial input power of the input light of the fiber amplifier and the working current of the pump source; A first judgment and control module, configured to, if the initial input power is less than or equal to a preset input power threshold, determine that the laser is in a closed state or the laser is abnormal, control the working mode of the pump source to switch from the first control mode to the second control mode, and maintain the second control mode within a preset delay time T0; wherein, the first control mode is a power automatic control mode, and the pump source in the power automatic control mode makes the fiber amplifier maintain a constant output power; the second control mode is a current automatic control mode, and the pump source in the current automatic control mode maintains a constant working current; The sampling module is used to sample the input light of the fiber amplifier at preset intervals. Perform N samplings and obtain the corresponding first input power to the Nth input power; where N-1 <m≦N,m=T0 / N is a positive integer; A second judgment and control module, configured to control the working state of the pump source based on the relationship between the first input power to the Nth input power and the preset input power threshold.

8. A lidar system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor loads and executes the computer program to implement the control method according to any one of claims 1 to 6.

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