A laser with a device protection system

Abstract

The present invention discloses a laser with a device protection system, belonging to the field of laser machine device protection technology. Designed to address the problem of poor fume cooling effectiveness of existing fume filtration devices, the present invention comprises: a laser with a device protection system connected to its rear end, the laser comprising a pump source, a forward combiner, a resonant cavity, a reverse combiner, and a stripper; the device protection system is equipped with a spectrometer, a first judgment setting unit, a second judgment setting unit, and an output head. The present invention achieves the purpose of protecting laser machine devices without affecting laser output power, beam quality, or the length of the energy transmission fiber.

Description

Technical Field

[0001] The present invention relates to the technical field of laser machine component protection, and in particular to a laser with a component protection system. Background Art

[0002] With the increase in the power of fiber-coupled high-power semiconductor pump sources and the improvement in the manufacturing level of fiber passive components, the output power of fiber lasers has also increased. However, the increase in output power has caused a sharp increase in the nonlinear effects of fiber lasers, among which the stimulated Raman scattering (SRS) effect is the most prominent. Due to the bidirectional transmission nature of SRS, when the SRS optical power reaches a certain level, it is easy to burn the front-end components, thereby causing the fiber laser to fail.

[0003] The SRS effect is a third-order nonlinear effect in which the incident laser interacts with the medium molecules to produce scattered light with a frequency different from the incident laser. Its intensity increases with the increase of the laser signal light power density and the length of the gain / energy transmission fiber. Currently, there are three main approaches to address this problem. The first is to use large-core gain / transfer fiber to reduce the signal light power density and increase the SRS threshold. However, large core fibers can severely affect the fiber laser beam quality and significantly reduce the threshold for other nonlinear effects, such as mode instability. The second approach is to use high-absorption wavelength pumps or shorter transfer fibers to reduce the length of the gain / transfer fiber to suppress the increase in SRS intensity. However, high-absorption wavelength pumps are expensive, and the absorption peak of the gain fiber corresponding to the high-absorption wavelength is narrow. Using high-absorption wavelength pumps can easily lead to unstable output laser power, and using shorter transfer fibers can hinder industrial application. The third approach is to insert a tilted grating into the fiber laser to direct the SRS laser power from the core into the cladding and then filter it out through a mode stripper. However, the SRS laser power is derived from the signal laser power, so this approach has an upper limit on the overall power output and can easily cause thermal damage to the mode stripper. Therefore, a cost-effective and reliable solution that does not compromise laser output power, beam quality, or transfer fiber length is needed. Summary of the Invention

[0004] The main purpose of the present invention is to provide a laser with a device protection system, aiming to solve the technical problem in the prior art that it is impossible to protect laser machine devices without affecting the laser output power, beam quality and energy transmission fiber length.

[0005] To achieve the above objectives, the present invention provides a laser with a device protection system:

[0006] The laser comprises a device protection system connected to the rear of the laser, the laser comprising a pump source 1, a forward beam combiner 2, a resonant cavity 3, a reverse beam combiner 4, and a stripper 5; the device protection system is provided with a spectrometer, a first judgment setting unit 16, a second judgment setting unit 17, and an output head 9;

[0007] The spectrometer is used to monitor a first difference M between a first-order stimulated Raman scattering (SRS) laser and a signal laser, and a second difference W between an n-1-order laser and an n-order SRS laser, wherein n is a positive integer greater than or equal to 2, and the first-order stimulated Raman scattering (SRS) laser is a first-order SRS laser;

[0008] The first judgment setting unit 16 is used to judge whether the first difference M is less than or equal to 30dB; when the first difference M is less than or equal to 30dB, only the first-level high-reflection grating 6 is provided in the device protection system; when the first difference M is greater than 30dB, no first-level high-reflection grating 6 is provided in the device protection system;

[0009] The second judgment setting unit 17 is used to judge whether the second difference W between the n-1 order SRS laser and the n-1 order SRS laser is less than or equal to 30 dB when the first difference M is less than or equal to 30 dB; when the second difference W between the n-1 order SRS laser and the n-1 order SRS laser is less than or equal to 30 dB, the device protection system is provided with a high-reflection grating set Q including m extracavity high-reflection gratings, where m is a positive integer greater than or equal to 1, and the extracavity high-reflection gratings are, in sequence, a first-level high-reflection grating 6, a second-level high-reflection grating 7, a third-level high-reflection grating 8 ... n-1-level high-reflection grating and an n-level high-reflection grating.

[0010] Optionally, an intracavity high-reflection grating 10 and an intracavity low-reflection grating 11 are provided in the resonant cavity 3, a gain fiber 12 is provided between the intracavity high-reflection grating 10 and the intracavity low-reflection grating 11, a first energy transmission fiber 13 is provided between the first-level high-reflection grating 6 and the second-level high-reflection grating 7, a second energy transmission fiber 14 is provided between the second-level high-reflection grating 7 and the third-level high-reflection grating 8, and a third energy transmission fiber 15 is provided between the third-level high-reflection grating 8 and the output head 9.

[0011] Optionally, the output end of the first-level high-reflection grating 6 is fused to one end of the first energy transmission optical fiber 13, the other end of the first energy transmission optical fiber 13 is fused to the input end of the second-level high-reflection grating 7, the output end of the third-level high-reflection grating 8 is fused to one end of the third energy transmission optical fiber 15, and the other end of the third energy transmission optical fiber 15 is fused to the input end of the output head 9.

[0012] Optionally, the number of the strippers 5 is one or more.

[0013] Optionally, the number of the laser and the number of the device protection system are both one, or the number of both are at least two.

[0014] Optionally, when the number of the lasers is at least two, all output optical fibers at the rear of the reverse combiners 4 of the lasers are fused to the same summing combiner 18 .

[0015] Optionally, the bundle combiner 18 is located before the stripper 5 .

[0016] Optionally, the laser reflectivity of each level of high-reflection grating in the high-reflection grating set Q to its working wavelength band is ≥99.5%.

[0017] Optionally, the optical fibers between the forward combiner 2 and the output head 9 have the same size.

[0018] Optionally, the laser includes fiber lasers with different powers, different wavelengths, different optical fibers, and different structures.

[0019] The beneficial effects of the present invention are as follows: the rear of the laser is connected to a device protection system, which includes a high-reflection grating set. The extracavity high-reflection grating in the high-reflection grating set Q can reflect the SRS laser that is transmitted in the reverse direction along the laser optical path into forward transmission, thereby protecting the front-end devices of the fiber laser and maintaining the forward transmission laser power, and can use long-power transmission optical fiber for laser transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of another embodiment of the present invention;

[0022] In the accompanying drawings, 1 is a pump source, 2 is a forward combiner, 3 is a resonant cavity, 4 is a reverse combiner, 5 is a mold stripper, 6 is a first-level high-reflection grating, 7 is a second-level high-reflection grating, 8 is a third-level high-reflection grating, 9 is an output head, 10 is an intra-cavity high-reflection grating, 11 is an intra-cavity low-reflection grating, 12 is a gain fiber, 13 is a first energy transmission fiber, 14 is a second energy transmission fiber, 15 is a third energy transmission fiber, 16 is a first judgment setting unit, 17 is a second judgment setting unit, and 18 is a summary combiner. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limitations on the present invention. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "inside" and "upper" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as limitations on the present invention.

[0024] In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, unless otherwise clearly specified and defined, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral whole; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] Reference Figure 1 In one embodiment of the present invention, a laser is included, wherein the output end of the laser is connected to a device protection system, and the laser includes a pump source 1, a forward beam combiner 2, a resonant cavity 3, a reverse beam combiner 4, and a stripper 5;

[0027] The device protection system is provided with a spectrometer, a first judgment setting unit 16, a second judgment setting unit 17 and an output head 9;

[0028] The spectrometer is used to monitor a first difference M between a first-order stimulated Raman scattering (SRS) laser and a signal laser, and a second difference W between an n-1-order laser and an n-order SRS laser, wherein n is a positive integer greater than or equal to 2, and the first-order stimulated Raman scattering (SRS) laser is a first-order SRS laser;

[0029] The first judgment setting unit 16 is used to judge whether the first difference M is less than or equal to 30dB; when the first difference M is less than or equal to 30dB, only the first-level high-reflection grating 6 is provided in the device protection system; when the first difference M is greater than 30dB, no first-level high-reflection grating 6 is provided in the device protection system;

[0030] The second judgment setting unit 17 is used to determine whether the second difference W between the n-1 order SRS laser and the n-1 order SRS laser is less than or equal to 30 dB when the first difference M is less than or equal to 30 dB; when the second difference W between the n-1 order SRS laser and the n-1 order SRS laser is less than or equal to 30 dB, the device protection system is provided with a high-reflection grating set Q including m extracavity high-reflection gratings, where m is a positive integer greater than or equal to 1, and the extracavity high-reflection gratings are, in sequence, a first-level high-reflection grating 6, a second-level high-reflection grating 7, a third-level high-reflection grating 8 ... n-1-level high-reflection grating and an n-level high-reflection grating.

[0031] In this embodiment, as the power of fiber-coupled high-power semiconductor pump sources increases and the manufacturing level of fiber passive components improves, the output power of the fiber laser also increases. However, this increase in output power causes a sharp increase in the nonlinear effects of the fiber laser, of which the most prominent is the stimulated Raman scattering (SRS) effect. Due to the bidirectional transmission nature of SRS lasers, when the SRS laser power reaches a certain level, it can easily burn out the front-end components, causing the fiber laser to fail. The SRS effect is a third-order nonlinear effect in which the incident laser interacts with the molecules of the medium, generating scattered light at a frequency different from the incident laser. The SRS laser intensity increases with the increase in the fiber laser signal light power density and the length of the gain / energy transfer fiber.

[0032] The setting of the multi-level high-reflection grating is conditional and related to the parameters and length of the energy transmission fiber. That is, when the difference between the first-order SRS laser and the signal laser is within 30dB, the first-level high-reflection grating 6 is set; when the difference between the second-order SRS laser and the first-order SRS laser is within 30dB, the second-level high-reflection grating 7 is set, and so on. The central wavelengths of the high-reflection gratings at each level are different. The first-level high-reflection grating 6 can only affect the first-order SRS laser, and the second-level high-reflection grating 7 can only affect the second-order SRS laser.

[0033] The resonant cavity 3 is provided with an intracavity high-reflection grating 10 and an intracavity low-reflection grating 11, a gain fiber 12 is provided between the intracavity high-reflection grating 10 and the intracavity low-reflection grating 11, a first energy transmission fiber 13 is provided between the first-level high-reflection grating 6 and the second-level high-reflection grating 7, a second energy transmission fiber 14 is provided between the second-level high-reflection grating 7 and the third-level high-reflection grating 8, and a third energy transmission fiber 15 is provided between the third-level high-reflection grating 8 and the output head 9.

[0034] In this embodiment, the pump source 1 is an electro-optical conversion device that converts electrical energy into semiconductor pump laser, and the number of pump sources 1 is at least two; the forward combiner combines the pump laser converted by the pump source 1 into one beam and injects it forward into the resonant cavity 3; the high-reflection grating 10 in the cavity is used to change the transmission direction of the signal laser and jointly screen the gain wavelength with the low-reflection grating 11 in the cavity; the gain fiber 12 is used to convert the pump laser into a signal laser; the reverse combiner 4 combines multiple pump laser beams into one beam and injects it backward into the resonant cavity 3; the stripper 5 is used to strip off the useless cladding light from the laser output from the laser.

[0035] The output end of the first-level high-reflection grating 6 is fused to one end of the first energy transmission optical fiber 13, the other end of the first energy transmission optical fiber 13 is fused to the input end of the second-level high-reflection grating 7, the output end of the third-level high-reflection grating 8 is fused to one end of the third energy transmission optical fiber 15, and the other end of the third energy transmission optical fiber 15 is fused to the input end of the output head 9.

[0036] The number of the strippers 5 is one or more.

[0037] In this embodiment, one or more strippers 5 can be used in a matched manner according to parameters such as the power of the laser for stripping the cladding and the stripping depth of the stripper 5 itself, and the multiple strippers 5 are connected in series.

[0038] Reference Figure 2 In another embodiment of the present invention, the number of the lasers and the device protection system is one, or the number is at least two. When the number of the lasers is at least two, all the output optical fibers behind the reverse combiners 4 of the lasers are fused to the same aggregate combiner 18, and the aggregate combiner 18 is located before the stripper 5.

[0039] In this embodiment, one or more strippers 5 can be used according to the parameters such as the power of the laser for stripping the cladding and the stripping depth of the stripper 5 itself, and multiple strippers 5 can be connected in series. Multiple lasers can be connected at the same time.

[0040] The laser reflectivity of each level of high-reflection grating in the high-reflection grating set to its working wavelength band is ≥99.5%.

[0041] In this embodiment, the multi-level high-reflection grating has a laser reflectivity of ≥99.5% in its working wavelength band, which can ensure that most of the SRS laser light transmitted in the reverse direction along the optical path is reflected to be transmitted in the forward direction.

[0042] The optical fibers between the forward combiner 2 and the output head 9 have the same size.

[0043] The optical fibers between the forward combiner 2 and the output head 9 have the same size, which can prevent signal light leakage and beam quality degradation caused by mismatch between different optical fibers.

[0044] The lasers include fiber lasers with different powers, different wavelengths, different optical fibers and different structures.

[0045] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A laser with a device protection system, characterized in that: The invention comprises a laser, wherein the output end of the laser is connected to a device protection system, the laser comprises a pump source (1), a forward beam combiner (2), a resonant cavity (3), a reverse beam combiner (4), and a mode stripper (5), and the laser comprises fiber lasers of different powers, different wavelengths, different optical fibers, and different structures; The device protection system is provided with a spectrometer, a first judgment setting unit (16), a second judgment setting unit (17) and an output head (9); The spectrometer is used to monitor a first difference M between a first-order stimulated Raman scattering (SRS) laser and a signal laser, and a second difference W between an n-1-order laser and an n-order SRS laser, wherein n is a positive integer greater than or equal to 2, and the first-order stimulated Raman scattering (SRS) laser is a first-order SRS laser; The first judgment setting unit (16) is used to judge whether the first difference M is less than or equal to 30 dB; when the first difference M is less than or equal to 30 dB, only a first-level high-reflection grating (6) is provided in the device protection system; when the first difference M is greater than 30 dB, no first-level high-reflection grating (6) is provided in the device protection system; The second judgment setting unit (17) is used to judge whether the second difference W between the n-1 order SRS laser and the n-1 order SRS laser is less than or equal to 30 dB when the first difference M is less than or equal to 30 dB; when the second difference W between the n-1 order SRS laser and the n-1 order SRS laser is less than or equal to 30 dB, a high-reflection grating set Q including m extracavity high-reflection gratings is provided in the device protection system, wherein m is a positive integer greater than or equal to 1, and the extracavity high-reflection gratings are sequentially a first-level high-reflection grating (6), a second-level high-reflection grating (7), a third-level high-reflection grating (8), ... an n-1-level high-reflection grating, and an n-level high-reflection grating; The laser reflectivity of each level of high-reflection grating in the high-reflection grating set Q to its working wavelength band is ≥99.5%.

2. A laser with a device protection system as claimed in claim 1, characterized in that: An intracavity high-reflection grating (10) and an intracavity low-reflection grating (11) are provided in the resonant cavity (3); a gain optical fiber (12) is provided between the intracavity high-reflection grating (10) and the intracavity low-reflection grating (11); a first energy transmission optical fiber (13) is provided between the first-level high-reflection grating (6) and the second-level high-reflection grating (7); a second energy transmission optical fiber (14) is provided between the second-level high-reflection grating (7) and the third-level high-reflection grating (8); and a third energy transmission optical fiber (15) is provided between the third-level high-reflection grating (8) and the output head (9).

3. A laser with a device protection system as claimed in claim 2, characterized in that: The output end of the first-level high-reflection grating (6) is fused to one end of the first energy transmission optical fiber (13), the other end of the first energy transmission optical fiber (13) is fused to the input end of the second-level high-reflection grating (7), the output end of the third-level high-reflection grating (8) is fused to one end of the third energy transmission optical fiber (15), and the other end of the third energy transmission optical fiber (15) is fused to the input end of the output head (9).

4. A laser with a device protection system as claimed in claim 1, characterized in that: The number of the strippers (5) is one or more.

5. The laser with a device protection system according to claim 1, characterized in that: The number of the laser and the number of the device protection system are both one, or the number of both is at least two.

6. A laser with a device protection system as claimed in claim 5, characterized in that: When the number of the lasers is at least two, all output optical fibers at the output ends of the reverse beam combiners (4) of the lasers are fused to the same summing beam combiner (18).

7. A laser with a device protection system as claimed in claim 6, characterized in that: The bundle combiner (18) is located before the stripper (5).

8. The laser with a device protection system according to claim 1, characterized in that: The optical fibers between the forward beam combiner (2) and the output head (9) have the same size.

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