A control method for a fiber laser device and the fiber laser device itself.

Abstract

This invention discloses a control method for a fiber laser device and the fiber laser device itself. The fiber laser device includes a fiber laser generator, which comprises a pump source, multiple optical signal detection devices, a laser relative intensity testing device, and a control device. The control method for the fiber laser device includes the following steps: obtaining a start command; upon receiving the start command, controlling the fiber laser generator to operate and output laser light; acquiring the laser wavelength signal and stimulated Raman scattering (SRS) wavelength signal of the output laser light collected by the multiple optical signal detection devices; calculating the relative intensity based on the laser wavelength signal and SRS wavelength signal; and adjusting the output laser wavelength and output power of the pump source or stabilizing it in the current operating state based on the relationship between the relative intensity and a set threshold. In this invention, the output parameters of the fiber laser generator are adjusted by the control device to suppress the SRS effect.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a control method for a fiber laser device and the fiber laser device itself. Background Technology

[0002] Fiber lasers are widely used in industrial processing, defense, and scientific research due to their advantages such as small size, compact structure, simple thermal management, maintenance-free all-fiber structure, high output beam quality, and high power. With the widespread application of fiber lasers in cutting, the demand for higher output power and brightness is increasing in pursuit of cutting efficiency. However, stimulated Raman scattering (SRS) in optical fibers is a major factor limiting the output power and brightness of fiber lasers. The occurrence of SRS in optical fibers not only affects the stability of the laser but can even lead to its damage. Summary of the Invention

[0003] The main objective of this invention is to provide a control method for a fiber laser device and a fiber laser device in general, with the aim of providing a control method for a fiber laser device and a fiber laser device capable of automatically suppressing stimulated Raman scattering.

[0004] To achieve the above objectives, the present invention proposes a control method for a fiber laser device, wherein the fiber laser device includes an electrically connected fiber laser generator, the fiber laser generator including a pump source, multiple optical signal detection devices, a laser relative intensity testing device, and a control device. The control method for the fiber laser device includes the following steps: Obtain the startup command; Upon receiving the start command, the fiber laser generator is controlled to operate and output laser light. Acquire the laser wavelength signal and stimulated Raman scattering light wavelength signal in the output laser collected by the multiple optical signal detection devices; The relative intensity is calculated based on the laser wavelength signal and the stimulated Raman scattering wavelength signal in the output laser.

[0005] Based on the relationship between relative intensity and a set threshold, the fiber laser generator is controlled to adjust the wavelength and output power of the laser output from the pump source or stabilize it in the current working state.

[0006] Optionally, the step of "controlling the fiber laser generator to adjust the wavelength and output power of the pump source output laser or stabilizing it in the current operating state based on the relationship between relative intensity and a set threshold" is described.

[0007] When the current relative intensity is lower than a set threshold, the fiber laser generator is controlled to adjust the wavelength and output power of the laser output from the pump source. The intensity of the output laser in the adjusted output laser collected by multiple optical signal detection devices is obtained, and the adjusted relative intensity is calculated. The change in laser output intensity is calculated by comparing the adjusted output laser intensity with the output laser intensity before adjustment. When the adjusted relative intensity is greater than or equal to the set threshold, and the change in laser output intensity meets the preset range, the fiber laser device is controlled to stabilize at the current pump source laser output wavelength and the current output power. When the adjusted relative intensity is lower than the set threshold, repeat the above steps of adjusting the wavelength and output power of the pump source output laser of the fiber laser generator.

[0008] Optionally, the preset range is: -0.5%. 0.5%.

[0009] Optionally, the step of "calculating the relative intensity based on the laser wavelength signal and the stimulated Raman scattering wavelength signal in the output laser" further includes: Obtain the relative intensity of the output laser as measured by the laser relative intensity testing device; The light transmittance of the optical signal detection device is controlled according to the relative measured intensity to correct the relative intensity until the current relative intensity equals the relative measured intensity.

[0010] The present invention also proposes a fiber laser device, the fiber laser device comprising: Fiber laser generator, used to output laser light; Multiple optical signal detection devices are installed inside the fiber laser generator to collect the laser wavelength signal, stimulated Raman scattering light wavelength signal, and output laser intensity value in the output laser of the fiber laser generator. A laser relative intensity testing device is used to measure the relative intensity of the output laser from the fiber laser generator; and, The control device is electrically connected to the fiber laser generator, the plurality of optical signal detection devices, and the laser relative intensity testing device. The control device includes a memory, a processor, and a control program for the fiber laser device stored in the memory and executable on the processor. The control program for the fiber laser device is configured to implement the steps of the control method for the fiber laser device described above.

[0011] Optionally, each of the optical signal detection devices includes: The power transmission fiber is used to provide the output laser signal; A cavity body, wherein the inner cavity of the cavity body is spherical, and the outer surface of the cavity body is provided with spaced through holes and light-transmitting holes, wherein the through holes allow the power transmission optical fiber to pass through, and the light-transmitting holes are provided with aperture adjustment devices; A filter element is disposed at the light-transmitting aperture; and, A photodetector is disposed on the filter to detect the laser signal that passes through the filter and is transmitted through the light-transmitting hole, and to convert the laser signal into an electrical signal and transmit it to the control device.

[0012] Optionally, the laser relative intensity testing device is a spectrometer used to measure the relative intensity of the output laser.

[0013] Optionally, the fiber laser generator includes: Two pump sources, including a forward pump source and a reverse pump source, are used to provide a laser source; Two pump optical couplers, each comprising double-clad optical fibers, wherein the inner cladding of the two double-clad optical fibers is coupled to the forward pump source and the reverse pump source, respectively. The fiber laser resonator is connected at both ends to the optical fibers of each of the pump optical couplers; Two cladding optical strippers, including a first stripper and a second stripper, wherein one end of the first stripper is electrically connected to the reverse pump source, and the other end of the first stripper is connected to the second stripper; the optical signal detection device performs spatial optical signal detection between the first stripper and the second stripper; and... The laser output head is connected to the second mold stripper to interconnect with the laser processing head and output laser light.

[0014] Optionally, each of the pump sources includes: Pumping semiconductor laser chips to convert electrical energy into divergent laser output; A heat sink device is used to dissipate heat from the pump semiconductor laser chip; A collimating lens is disposed on one side of the pump semiconductor laser chip to collimate the diverging laser output from the pump semiconductor laser chip into parallel light. A volume grating is disposed on the side of the collimating lens away from the pump semiconductor laser chip to adjust the laser wavelength of the pump semiconductor laser chip; A focusing lens is disposed on the side of the volume grating away from the pump semiconductor laser chip to focus the laser output from the pump semiconductor laser chip; An optical fiber end cap is disposed on the side of the focusing lens away from the pump semiconductor laser chip, and the focal point of the focused beam converges at the optical fiber end cap; and, The pump light output fiber is disposed on the side of the fiber end cap away from the pump semiconductor laser chip, and is used to output the pump laser.

[0015] Optionally, the volume grating is provided with piezoelectric ceramic or a temperature control plate.

[0016] In the technical solution of this invention, after obtaining the start command, the fiber laser generator is controlled to work and output laser light. When the output power of the output laser reaches a certain intensity, the stimulated Raman scattering effect in the fiber will affect the output power and brightness of the output laser. Therefore, the laser wavelength signal and the stimulated Raman scattering wavelength signal in the output laser are detected by the multiple optical signal detection devices. The relative intensity is calculated based on the detected laser wavelength signal and the stimulated Raman scattering wavelength signal. When the relative intensity is lower than a set threshold, it indicates that the stimulated Raman scattering effect has an impact on the stability of the fiber laser device. Therefore, the wavelength and output power of the pump source output laser of the fiber laser generator are adjusted by the control device, thereby reducing the impact of the stimulated Raman scattering effect on the fiber laser device while ensuring that the output power is stable within a certain range, and improving the working stability of the fiber laser device. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a structure of an embodiment of the fiber laser device provided by the present invention; Figure 2 for Figure 1 A schematic diagram of the optical signal detection device; Figure 3 for Figure 1 A schematic diagram of a fiber optic laser generator; Figure 4 A comparison diagram of the output laser wavelength signal and the stimulated Raman scattering wavelength signal.

[0019] Explanation of icon numbers:

[0020] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0023] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0024] Fiber lasers are widely used in industrial processing, defense, and scientific research due to their advantages such as small size, compact structure, simple thermal management, maintenance-free all-fiber structure, high output beam quality, and high power. With the widespread application of fiber lasers in cutting, the demand for higher output power and brightness is increasing in pursuit of cutting efficiency. However, stimulated Raman scattering (SRS) in optical fibers is a major factor limiting the output power and brightness of fiber lasers. The occurrence of SRS in optical fibers not only affects the stability of the laser but can even lead to its damage.

[0025] To address the above problems, this invention proposes a control method for a fiber laser device and a fiber laser device itself. Figures 1 to 4 This is a schematic diagram of the control method for the fiber laser device of the present invention and an embodiment of the fiber laser device.

[0026] Please refer to Figure 1This invention proposes a fiber laser device 1000, which includes an electrically connected fiber laser generator 1, multiple optical signal detection devices 2, a laser relative intensity testing device 3, and a control device 4. The fiber laser generator 1 is used to output laser light. The multiple optical signal detection devices 2 are used to collect the laser wavelength signal, stimulated Raman scattering light wavelength signal, and output laser intensity value of the output laser light from the fiber laser generator 1. The laser relative intensity testing device 3 is used to measure the relative intensity of the output laser light from the fiber laser generator 1. The control device 4 is electrically connected to the fiber laser generator 1, the multiple optical signal detection devices 2, and the laser relative intensity testing device 3. The control device 4 includes a memory, a processor, and a control program for the fiber laser device 1000 stored in the memory and executable on the processor. The control program for the fiber laser device 1000 is configured to implement the steps of a control method for the fiber laser device 1000.

[0027] In the technical solution of this invention, after obtaining the start command, the fiber laser generator 1 is controlled to operate and output laser light. When the output power of the output laser reaches a certain intensity, the stimulated Raman scattering effect in the fiber will affect the output power and brightness of the output laser. Therefore, the laser wavelength signal and the stimulated Raman scattering light wavelength signal in the output laser are detected by the multiple optical signal detection devices 2. The relative intensity is calculated based on the detected laser wavelength signal and stimulated Raman scattering light wavelength signal. At the same time, the relative intensity is detected by the laser relative intensity testing device 3 to obtain the relative measured intensity. The relative measured intensity is then used to determine the relative intensity of the laser. The calculated relative intensity is corrected to make the relative intensity equal to the relative measured intensity. Then, the corrected relative intensity is compared with a set threshold. When the corrected relative intensity is lower than the set threshold, it indicates that the stimulated Raman scattering effect has an impact on the stability of the fiber laser device 1000. Therefore, the control device 4 adjusts the wavelength and output power of the laser output from the pump source 11 of the fiber laser generator 1, thereby reducing the impact of stimulated Raman scattering on the fiber laser device 1000 while ensuring that the output power is stable within a certain range, and improving the stability of the fiber laser device 1000.

[0028] Please see Figure 2To better detect the laser wavelength and stimulated Raman scattering wavelength in the output laser, each of the optical signal detection devices 2 includes a power transmission fiber 21, a cavity 22, a filter 23, and a photodetector 24. The power transmission fiber 21 provides the output laser signal. The cavity 22 has a spherical inner cavity and an outer surface with spaced through holes and light-transmitting holes 222. The through holes allow the power transmission fiber 21 to pass through. An aperture adjustment device 223 is provided at the light-transmitting hole 222. The filter 23 is located at the light-transmitting hole 222. The photodetector 24 is located at the filter 23 to detect the laser signal passing through the filter 23 from the light-transmitting hole 222, convert the laser signal into an electrical signal, and transmit it to the control device 4. Specifically, the power transmission fiber 21 is connected to the laser generator and is used to receive the laser generated by the laser generator. In the scheme of this application, the inner cavity of the cavity body 22 can be a regular shape such as spherical or ellipsoidal, without limitation. The inner cavity of the cavity body 22 can uniformly distribute the laser signal radiated by the power transmission fiber 21 and the stimulated Raman scattering light signal into the inner cavity, thereby ensuring the stability of the light signal output from the light-transmitting hole 222. It can be understood that the light-transmitting hole 222 is provided at the center of the upper end face of the cavity body 22. The light-transmitting hole 222 can be set as circular, and an aperture adjustment is provided at the light-transmitting hole 222. Specifically, the aperture adjustment device 223 can be a flange device. The aperture adjustment device 223 and the light-transmitting hole 222 cooperate to adjust the amount of light transmitted, thereby controlling the intensity of the transmitted light signal. In addition, a filter 23 is also provided at the light-transmitting hole 222. The filter 23 is an optical filter 23 with wavelength selectivity, which can retain the laser signal and stimulated Raman scattering light signal required by this application, and filter out the influence of stray light in other bands. After receiving the required laser signal and stimulated Raman scattering light signal, the photodetector 24 converts the light signal into a current or voltage signal and transmits it to the control device 4.

[0029] In addition, to ensure the accuracy of the laser relative intensity correction, the laser relative intensity testing device 3 is a spectrum analyzer used to measure the relative intensity of the output laser. After comparing the relative measured intensity with the calculated relative intensity, the signal detection device is adjusted to ensure that the calculated relative intensity is consistent with the relative measured intensity, thus completing the laser relative intensity correction.

[0030] Please see Figure 1In an embodiment of the present invention, the fiber laser generator 1 includes two pump sources 11, two pump optical couplers 12, a fiber laser resonator 13, two cladding optical strippers 14, and a laser output head 15. In this embodiment, the two pump sources 11 include a forward pump source 11 and a reverse pump source 11, which are used to provide a laser source. The two pump optical couplers 12 include double-clad optical fibers, and the inner cladding of the two double-clad optical fibers is coupled to the forward pump source 11 and the reverse pump source 11, respectively. The fiber laser resonator 13... The two ends are respectively connected to the optical fibers of each of the pump optical couplers 12. The two cladding optical strippers 14 include a first stripper 141 and a second stripper 142. One end of the first stripper 141 is electrically connected to the reverse pump source 11, and the other end of the first stripper 141 is connected to the second stripper 142. The optical signal detection device 2 performs spatial signal light detection between the first stripper 141 and the second stripper 142. The laser output head 15 is connected to the second stripper 142 for interconnection with the laser processing head to output laser.

[0031] It is understood that the pump source 11 is a semiconductor optical fiber output pump source 11. In this application, the pump source 11 includes a set of forward pump sources 11 and a set of reverse pump sources 11. The forward pump source 11 is connected to a pump optical coupler 12. The pump optical coupler 12 is connected to one end of the fiber laser resonator 13. The other end of the fiber laser resonator 13 is connected to another pump optical coupler 12 connected to the reverse pump source 11. Specifically, the wavelength range of the pump source 11 is 900-1000nm. The core diameter of the semiconductor output fiber is 100-220um, and the numerical aperture range is 0.15-0.22. It is used to provide energy to the resonant cavity and gain medium. The pump optical coupler 12 is used to couple multiple pump sources 11 into the inner cladding of the double-clad fiber. Specifically, a coupling method of (6+1)×1 or (18+1)×1 can be adopted.

[0032] In addition, the fiber laser resonator 13 amplifies the wavelength of the pump source 11 to the output laser wavelength, wherein the output laser wavelength ranges from 1030 to 1090 nm. The fiber laser resonator 13 is composed of a pair of high-reflection fiber gratings 131 and low-reflection fiber gratings 133 and double-clad ytterbium-doped fiber 132. More specifically, the high-reflection fiber gratings 131 and low-reflection fiber gratings 133 are double-clad fiber Bragg gratings or chirped fiber gratings. Furthermore, the core diameter of the double-clad fiber is 20 nm. The fiber grating has a diameter of -30 μm, a numerical aperture of 0.04-0.07, an inner cladding diameter of 350-600 μm, a numerical aperture of 0.4-0.5, a center wavelength range of 1030-1090 nm, a high-reflectivity fiber grating 131 with a reflectivity greater than 99% and a 3dB bandwidth of 2-3 nm, and a low-reflectivity fiber grating 133 with a reflectivity of 10%±5% and a 3dB bandwidth of 1-1.5 nm. It should be noted that when using chirped fiber gratings for connection, attention must be paid to the directionality of the connection. The double-clad ytterbium-doped fiber is used to provide population inversion to amplify the output laser. The double-clad ytterbium-doped fiber has a core diameter of 20-30 μm and a numerical aperture of 0.04-0.07. The inner cladding diameter is 350-600 μm and the numerical aperture is 0.4-0.5. The absorption of the pump wavelength is 0.3-1.5 dB / m. The fiber laser resonator 13 is connected to the first stripper 141 to strip the cladding laser and residual cladding pump light generated in the fiber laser resonator 13. The other end of the first stripper 141 is electrically connected to one end of the optical signal detection device 2. The second stripper 142 is electrically connected to the other end of the optical signal detection device 2. The second stripper 142 is used to remove the reflected light from the processing output to avoid the reflected light affecting the measurement accuracy of the optical signal detection device 2. A laser output head 15 is connected after the second stripper 142 to cooperate with the laser processing head to process materials. In addition, the laser output head 15 can be configured with a standard interface such as QCS, QBH or QD for interconnection with the laser processing head, and there are no restrictions on this.

[0033] Please refer to Figure 3In order to adjust the output power and wavelength of the fiber laser generator 1, the pump source 11 needs to be controlled. Therefore, in this application, each pump source 11 includes a pump semiconductor laser chip 111, a heat sink device 112, a volume grating 114, a focusing lens 115, an optical fiber end cap 116, and a pump light output optical fiber 117. The pump semiconductor laser chip 111 is used to convert electrical energy into divergent laser output. The heat sink 112 is arranged around the outside of the pump semiconductor laser chip 111 to dissipate heat from the pump semiconductor laser chip 111. The collimating lens 113 is disposed on one side of the pump semiconductor laser chip 111 to collimate the divergent laser output by the pump semiconductor laser chip 111 into parallel light, facilitating wavelength adjustment by the volume grating 114. The volume grating 114 is disposed on the side of the collimating lens 113 away from the pump semiconductor laser chip 111 to adjust the laser wavelength of the pump semiconductor laser chip 111. The focusing lens 11... A focusing lens 115 is positioned on the side of the volume grating 114 away from the pump semiconductor laser chip 111 to focus the laser output from the pump semiconductor laser chip 111. An optical fiber end cap 116 is positioned on the side of the focusing lens 115 away from the pump semiconductor laser chip 111. The optical fiber end cap 116 increases the fiber end face area, reduces the fiber end face energy density, and prevents the fiber end face from burning out due to excessive energy density. The focal point of the focused beam is converged at the optical fiber end cap 116. A pump light output fiber 117 is positioned on the side of the optical fiber end cap 116 away from the pump semiconductor laser chip 111 to output the pump laser. Furthermore, the pump semiconductor laser chip 111 is connected to a constant current driving board, and the control device 4 can adjust the constant current driving board to control the power of the laser output from the pump semiconductor laser chip 111.

[0034] Specifically, a piezoelectric ceramic 1141 or a temperature control plate 1142 is disposed on the volume grating 114 to adjust the wavelength of the output laser. In the embodiments of this application, the piezoelectric ceramic 1141 or the temperature control plate 1142 is disposed in the symmetrical direction of the volume grating 114. The piezoelectric ceramic 1141 can adjust the stress applied to the volume grating 114 by changing the voltage, and the temperature control plate 1142 can adjust the temperature of the volume grating 114 by changing the current. Under changes in stress and temperature, the effective refractive index of the grating region of the volume grating 114 changes, thereby changing the center wavelength of the refraction of the volume grating 114 and thus controlling the output wavelength.

[0035] Furthermore, the control device 4 includes a memory, a processor, and a control program for the fiber laser device 1000 stored in the memory and executable on the processor. The control program for the control method of the fiber laser device 1000 is configured to implement the steps of the control method of the fiber laser device 1000.

[0036] The control device 4 may include a processor, such as a central processing unit (CPU), a communication bus, a user interface, a network interface, and memory. The communication bus is used to enable communication between these components. The user interface may include a display screen, an input unit such as a keyboard, and optionally, a standard wired or wireless interface. The network interface may optionally include a standard wired or wireless interface (such as a Wi-Fi interface). The memory may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk drive. Alternatively, the memory may be a storage device independent of the aforementioned processor.

[0037] Those skilled in the art will understand that the control device 4 may include more or fewer components than those described above, or combine certain components, or have different component arrangements.

[0038] In the control device 4, the network interface is mainly used for data communication with other devices; the user interface is mainly used for data interaction with the user; the processor and memory in the control device 4 can be located in the control device 4. The control device 4 calls the control program of the fiber laser device 1000 stored in the memory through the processor and executes the control method of the fiber laser device 1000 provided in the embodiment of the present invention. Specifically, the control device 4 performs at least the following steps: Obtain the startup command; Upon receiving the start command, the fiber laser generator 1 is controlled to operate and output laser light. Acquire the laser wavelength signal in the output laser collected by the multiple optical signal detection devices 2. Stimulated Raman scattering wavelength signal ; According to the laser wavelength signal in the output laser Stimulated Raman scattering wavelength signal The relative intensity was calculated; Based on the relationship between relative intensity and a set threshold, the fiber laser generator 1 is controlled to adjust the wavelength and output power of the laser output from the pump source 11 or stabilize it in the current working state.

[0039] This invention provides a control method for a fiber laser device 1000, comprising the following steps: S10, Obtain the startup command; It is understandable that during the operation of the fiber laser device 1000, the influence of stimulated Raman scattering will be aggravated as the output power and brightness are gradually increased. The start command mentioned here refers to the start signal received when the fiber laser device 1000 starts working, such as a power-on signal or a switch signal, etc., which is not limited here.

[0040] S20: After receiving the start command, control the fiber laser generator 1 to work and output laser; According to the start command, the fiber laser generator 1 is controlled to start working, and the pump source 11 is started to provide a laser source.

[0041] S30, acquire the laser wavelength signal in the output laser collected by the plurality of optical signal detection devices 2. Stimulated Raman scattering wavelength signal ; In the technical solution of this invention, when the fiber laser device 1000 is working, it generates a laser signal and a stimulated Raman scattering light signal. When the stimulated Raman scattering effect occurs, the energy of the laser wavelength is transferred to the stimulated Raman scattering wavelength. In the optical fiber, the stimulated Raman light wavelength and the laser wavelength have the following relationship:

[0042] in, The frequency shift of stimulated Raman light relative to laser light in silica optical fiber is related to the fiber material. Approximately 13 THz, where C is the speed of light in a vacuum. This is a laser wavelength signal. The wavelength of the stimulated Raman scattered light in the optical fiber is the difference between the wavelength of the laser light and the wavelength of the light in the optical fiber. Therefore, the wavelength of the stimulated Raman scattered light in the optical fiber can be calculated using the following formula. : = +

[0043] For example, laser wavelength signal The wavelength signal of stimulated Raman scattering of a 1080nm laser in a quartz optical fiber. It is approximately 1132nm.

[0044] According to the laser wavelength signal and stimulated Raman scattering wavelength signal The difference between the two can be addressed by setting a filter 23 at the photodetector 24. In this embodiment, the number of optical signal detection devices 2 is set to three. One of the optical signal detection devices 2 can be configured to allow only laser signals to pass through, while another filter 23 can be configured to allow only stimulated Raman scattering light wavelength signals to pass through. These are used to detect the current wavelength of the laser signal. and the current stimulated Raman scattering wavelength signal It should be noted that the optical signal detection device 2 for detecting the current laser signal and the optical signal detection device for detecting the current stimulated Raman scattering light wavelength signal can be photodetectors 24 with the same wavelength response or photodetectors 24 with different wavelength responses. There are no restrictions on their specific settings and measurement order.

[0045] S40, based on the laser wavelength signal in the output laser Stimulated Raman scattering wavelength signal The relative intensity was calculated; relative intensity The relative intensity is generally calculated using the following formula:

[0046] This is used to characterize the degree of influence of stimulated Raman scattering on the fiber laser device 1000, through relative intensity. The magnitude of the intensity is used to measure the impact of stimulated Raman scattering on the stability of a laser system. Generally, the relative intensity... The larger the value, the greater the laser wavelength signal is compared to the stimulated Raman scattering light wavelength signal. Therefore, the less the stimulated Raman scattering light affects the stability of the fiber laser device 1000, and the lower the relative intensity. The smaller the value, the closer the laser wavelength signal is to the stimulated Raman scattering light wavelength signal. At this point, the greater the impact of stimulated Raman scattering light on the stability of the fiber laser device 1000, the more significant the relative intensity. When a certain threshold is reached, measures need to be taken to reduce the wavelength of stimulated Raman scattering light.

[0047] S50, based on the relationship between relative intensity and a set threshold, control the fiber laser generator 1 to adjust the wavelength and output power of the laser output from the pump source 11 or stabilize it in the current working state.

[0048] Specifically, in one embodiment of the present invention, the set threshold is set to 30dB. It is understood that, under normal circumstances, when When the stimulated Raman scattering signal is ≥30dB, the effect of the stimulated Raman scattering signal on the stability of the fiber laser device 1000 is negligible or has little impact, and the fiber laser generator is controlled to remain stable in its current operating state; while when When the intensity is <30dB, the stimulated Raman scattering signal has a significant impact on the stability of the fiber laser device 1000. Therefore, it is necessary to adjust the wavelength and output power of the output laser from the fiber laser generator 1 to increase the relative intensity. This ensures that the set threshold relationship is satisfied.

[0049] Specifically, the step of "controlling the fiber laser generator to adjust the wavelength and output power of the laser output from the pump source 11 or to stabilize it in the current operating state according to the relationship between relative intensity and a set threshold" includes: S501, when the current relative intensity is lower than a set threshold, control the fiber laser generator 1 to adjust the wavelength and output power of the laser output by the pump source 11; According to the above embodiments, for example, when the threshold is set to 30dB, the current relative intensity When the value is <30dB, it indicates that the stimulated Raman scattering light signal has a significant impact on the stability of the fiber laser device. It is necessary to adjust the wavelength and output power of the laser output from the pump source 11 of the fiber laser generator 1 to increase the relative intensity.

[0050] Specifically, in this embodiment, the volume grating 114 is disposed on the side of the collimating lens 113 away from the pump semiconductor laser chip 111, and can adjust the laser wavelength of the pump semiconductor laser chip 111. Specifically, the center wavelength selected by the volume grating 114 can be characterized by the following formula:

[0051] in, The center wavelength selected for the bulk grating 114 ， The effective refractive index of the grating region, To control the grating period, the control system controls the piezoelectric ceramic 1141 or temperature control plate 1142 disposed on the bulk grating 114, thereby controlling the stress and temperature of the bulk grating 114 to change the effective refractive index of the grating region. In order to change the output laser wavelength, the control device 4 adjusts the power of the output laser of the pump source 11 through the constant current drive board, and then obtains the adjusted output laser.

[0052] S502, acquire the intensity of the output laser in the adjusted output laser collected by the multiple optical signal detection devices and calculate the adjusted relative intensity; In this embodiment, the number of optical signal detection devices 2 is set to three. Two of these devices are used to detect the laser wavelength and stimulated Raman scattering wavelength signals in the adjusted output laser, while the remaining device is used to detect the laser wavelength before adjustment. This is to monitor the stability of the output laser power after automatic adjustment, ensuring that the final output laser intensity remains constant. It should be noted that the filter 23 of the optical signal detection device 2 used to detect the laser wavelength before adjustment is configured to only allow the laser wavelength to pass through. The three optical signal detection devices 2 can have the same wavelength response or different wavelength responses, and there are no restrictions on their installation order. Furthermore, by detecting the adjusted laser wavelength signal and stimulated Raman scattering wavelength signal through multiple optical signal detection devices 2, the adjusted relative intensity can be obtained. .

[0053] S503, calculate the change in laser output intensity by comparing the adjusted output laser intensity with the output laser intensity before adjustment. ; Since the laser intensity changes before and after adjustment, the corresponding change in laser output intensity is calculated by the control system. , specifically It equals the adjusted laser intensity minus the unadjusted laser intensity, and is used to characterize the change in laser output intensity before and after adjustment.

[0054] S504, when the adjusted relative intensity is greater than or equal to the set threshold, and the change in laser output intensity is... When the preset range is met, the fiber laser device 1000 is controlled to stabilize at the current laser output wavelength and current output power of the pump source 11. When the adjusted relative intensity is greater than or equal to the set threshold, the stimulated Raman scattering light signal has no or minimal impact on the stability of the fiber laser device 1000, and can be ignored. Furthermore, based on the change in laser output intensity... Matching with a preset range is used to constrain the adjusted laser intensity to be equal to the laser intensity before adjustment, or to limit the change in laser intensity before and after adjustment to a small range, so as to ensure that while suppressing stimulated Raman scattering, the intensity of the output laser does not change significantly. At this time, the fiber laser generator is controlled to stabilize in the current working state.

[0055] S505, when the adjusted relative intensity is lower than the set threshold, repeat the above steps of adjusting the wavelength and output power of the output laser of the pump source 11 of the fiber laser generator 1.

[0056] If the adjusted relative intensity is greater than or equal to the set threshold but still lower than the set threshold, repeat the above adjustment steps for the pump source 11 to increase the relative intensity after the second adjustment until the above requirements are met.

[0057] It is understood that the preset range is -0.5%. 0.5%, the change in output laser intensity before and after adjustment. Within the range of -0.5% to 0.5%, the intensity of the laser output can be guaranteed not to change significantly, thereby reducing the influence of stimulated Raman scattering while ensuring that the laser intensity remains relatively constant.

[0058] In another embodiment, the phrase "based on the laser wavelength signal in the output laser" is... Stimulated Raman scattering wavelength signal After the step of "calculating the relative intensity" is completed, the following steps are also included: S401, Obtain the relative intensity of the output laser measured by the laser relative intensity testing device 3; It is understood that the laser relative intensity testing device 3 is an optical spectrum analyzer (OSA), which is an optical instrument used to test the intensity of a single light signal or the relative intensity of multiple light signals, and thus can detect the relative intensity of laser light and stimulated Raman scattering light.

[0059] S402, the light transmission of the optical signal detection device 2 is controlled according to the relative measurement intensity to correct the relative intensity until the current relative intensity is equal to the relative measurement intensity.

[0060] Since there is a certain difference between the calculated relative intensity and the relative measured intensity, the light transmission of the optical signal detection device 2 can be adjusted. Specifically, the aperture adjustment device 223 can be adjusted to change the laser intensity entering the photodetector 24, so that the adjusted calculated relative intensity is equal to the relative measured intensity, thereby achieving the final correction effect.

[0061] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A control method for a fiber laser device, characterized in that, The fiber laser device includes an electrically connected fiber laser generator, which includes a pump source, multiple optical signal detection devices, a laser relative intensity testing device, and a control device. Each of the aforementioned optical signal detection devices includes: Power transmission fiber, used to provide the output laser signal; A cavity body, wherein the inner cavity of the cavity body is spherical, and the outer surface of the cavity body is provided with spaced through holes and light-transmitting holes, wherein the through holes allow the power transmission optical fiber to pass through, and the light-transmitting holes are provided with aperture adjustment devices; A filter element is disposed at the light-transmitting aperture; and, A photodetector, disposed on the filter, is used to detect the laser signal transmitted through the light-transmitting hole and passing through the filter, and convert the laser signal into an electrical signal and transmit it to the control device; The control method for the fiber laser device includes the following steps: Obtain the startup command; Upon receiving the start command, the fiber laser generator is controlled to operate and output laser light. Acquire the laser wavelength signal and stimulated Raman scattering light wavelength signal in the output laser collected by the multiple optical signal detection devices; The relative intensity is calculated based on the laser wavelength signal and the stimulated Raman scattering light wavelength signal in the output laser. Based on the relationship between relative intensity and a set threshold, the fiber laser generator is controlled to adjust the wavelength and output power of the laser output from the pump source or stabilize it in the current working state. The step of "calculating the relative intensity based on the laser wavelength signal and the stimulated Raman scattering light wavelength signal in the output laser" further includes: Obtain the relative intensity of the output laser as measured by the laser relative intensity testing device; The light transmittance of the optical signal detection device is controlled according to the relative measured intensity to correct the relative intensity until the current relative intensity equals the relative measured intensity.

2. The control method for the fiber laser device as described in claim 1, characterized in that, The step of "controlling the fiber laser generator to adjust the wavelength and output power of the pump source output laser or to stabilize it in the current working state according to the relationship between relative intensity and a set threshold" includes: When the current relative intensity is lower than a set threshold, the fiber laser generator is controlled to adjust the wavelength and output power of the laser output from the pump source. The intensity of the output laser in the adjusted output laser collected by multiple optical signal detection devices is obtained, and the adjusted relative intensity is calculated. The change in laser output intensity is calculated by comparing the adjusted output laser intensity with the output laser intensity before adjustment. When the adjusted relative intensity is greater than or equal to the set threshold, and the change in laser output intensity meets the preset range, the fiber laser device is controlled to stabilize at the current pump source laser output wavelength and the current output power. When the adjusted relative intensity is lower than the set threshold, repeat the steps of adjusting the wavelength and output power of the pump source output laser in the fiber laser generator.

3. The control method for the fiber laser device as described in claim 2, characterized in that, The preset range is -0.5% to 0.5%.

4. A fiber laser device, characterized in that, include: Fiber laser generator, used to output laser light; Multiple optical signal detection devices are installed inside the fiber laser generator to collect the laser wavelength signal, stimulated Raman scattering light wavelength signal, and output laser intensity value in the output laser of the fiber laser generator. A laser relative intensity testing device is used to measure the relative intensity of the output laser from the fiber laser generator; and, A control device is electrically connected to the fiber laser generator, the plurality of optical signal detection devices, and the laser relative intensity testing device. The control device includes a memory, a processor, and a control program for the fiber laser device stored in the memory and executable on the processor. The control program for the fiber laser device is configured to implement the steps of the control method for the fiber laser device as described in any one of claims 1 to 3.

5. The fiber laser device as described in claim 4, characterized in that, The laser relative intensity testing device is a spectral analyzer, used to measure the relative intensity of the output laser.

6. The fiber laser device as described in claim 4, characterized in that, The fiber laser generator includes: Two pump sources, including a forward pump source and a reverse pump source, are used to provide a laser source; Two pump optical couplers, each comprising double-clad optical fibers, wherein the inner cladding of the two double-clad optical fibers is coupled to the forward pump source and the reverse pump source, respectively. The fiber laser resonator is connected at both ends to the optical fibers of each of the pump optical couplers; Two cladding optical strippers, including a first stripper and a second stripper, wherein one end of the first stripper is connected to the reverse pump source fiber, and the other end of the first stripper is connected to the second stripper; the optical signal detection device performs spatial optical signal detection between the first stripper and the second stripper; and... The laser output head is connected to the second mold stripper to interconnect with the laser processing head and output laser light.

7. The fiber laser device as described in claim 6, characterized in that, Each of the pump sources includes: Pumping semiconductor laser chips to convert electrical energy into divergent laser output; A heat sink device is used to dissipate heat from the pump semiconductor laser chip; A collimating lens is disposed on one side of the pump semiconductor laser chip to collimate the diverging laser output from the pump semiconductor laser chip into parallel light. A volume grating is disposed on the side of the collimating lens away from the pump semiconductor laser chip to adjust the laser wavelength of the pump semiconductor laser chip; A focusing lens is disposed on the side of the volume grating away from the pump semiconductor laser chip to focus the laser output from the pump semiconductor laser chip; An optical fiber end cap is disposed on the side of the focusing lens away from the pump semiconductor laser chip, and the focal point of the focused beam converges at the optical fiber end cap; and, The pump light output fiber is disposed on the side of the fiber end cap away from the pump semiconductor laser chip, and is used to output the pump laser.

8. The fiber laser device as described in claim 7, characterized in that, The volume grating is equipped with piezoelectric ceramics or a temperature control plate.

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