CN113794091B - Laser and multi-wavelength output laser processing system - Google Patents
Laser and multi-wavelength output laser processing system Download PDFInfo
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- CN113794091B CN113794091B CN202010450858.3A CN202010450858A CN113794091B CN 113794091 B CN113794091 B CN 113794091B CN 202010450858 A CN202010450858 A CN 202010450858A CN 113794091 B CN113794091 B CN 113794091B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
- H01S3/06745—Tapering of the fibre, core or active region
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/20—Bonding
- B23K26/21—Bonding by welding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
- H01S3/06729—Peculiar transverse fibre profile
- H01S3/06733—Fibre having more than one cladding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/0675—Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
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- Engineering & Computer Science (AREA)
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- Lasers (AREA)
Abstract
The embodiment of the invention provides a laser and a multi-wavelength output laser processing system, wherein the laser comprises a pumping assembly for providing pumping light, an active optical fiber and an optical fiber output device; the active optical fiber is used for partially absorbing the pump light and amplifying the signal light, the fiber core of the active optical fiber is used for transmitting the signal light, and the cladding of the active optical fiber is used for transmitting the pump light which is not absorbed; the optical fiber output device is used for transmitting the composite laser output by the active optical fiber. The laser and the multi-wavelength output laser processing system provided by the embodiment of the invention have the advantages of fewer devices and low cost.
Description
Technical Field
The invention relates to the technical field of lasers, in particular to a laser and a multi-wavelength output laser processing system.
Background
With the rapid development of the manufacturing technology of optical fibers and semiconductor lasers, the output power of the optical fibers and the semiconductor lasers is greatly increased, and a compound welding technology of forming two or more laser beams by utilizing single laser beam splitting or compounding a plurality of laser beams can provide a feasible solving direction for high-quality precision welding.
In one existing scheme, the dual-light path composite laser welding technology needs a beam splitter to generate dual light beams, or needs two discrete lasers to generate dual light beams, then utilizes a composite welding head of a dual main light path to combine two laser light beams, and utilizes different absorption and heating characteristics of the two light beams on materials to realize high-quality processing of the materials.
The scheme needs two independent lasers, two independent laser output heads, two laser power input ports and a multiplexing type composite laser processing head of a collimation light path, so that not only is the cost high and the cost high due to excessive lasers and processing components on one hand, but also the potential reliability hazards are caused by greatly increasing the optical and control complexity of the whole system, and the size of the system is too large due to multi-port input, so that the system is limited in some special application scenes, and the flexible processing capability of the composite laser is weakened.
In another approach, to avoid the use of high cost, high complexity multi-port input compound laser processing heads, spatial multi-laser beam combining is achieved by fusion splicing multiple fiber laser output fibers to one quartz output head. This solution also in principle requires a plurality of individual fiber lasers, which can lead to high costs, and because of the non-coaxial, asymmetric output fiber distribution, requires that the laser head has to perform laser processing in a specific direction, increasing the process complexity of laser processing.
Therefore, the existing double-beam laser composite welding technology has the problems of high cost and complex processing technology.
Disclosure of Invention
In view of the above, embodiments of the present invention have been made to provide a laser and a multi-wavelength output laser processing system that overcome or at least partially solve the above problems.
In order to solve the above-mentioned problems, an embodiment of the present invention discloses a laser, including:
a pump assembly for providing pump light, an active optical fiber and an optical fiber output device;
the active optical fiber is used for partially absorbing the pump light and amplifying the signal light, the fiber core of the active optical fiber is used for transmitting the signal light, and the cladding of the active optical fiber is used for transmitting the pump light which is not absorbed; the optical fiber output device is used for transmitting the composite laser output by the active optical fiber.
Optionally, the active optical fiber has an absorptivity of greater than 0 and less than 15dB;
optionally, the active optical fiber has an absorptivity of greater than 0 and less than 10dB.
Optionally, the active optical fiber has a length of less than 50 meters.
Optionally, the active optical fiber has a length of less than 20 meters.
Optionally, the active optical fiber has a length of less than 10 meters.
Optionally, the method further comprises: and the fiber Bragg gratings FBG are arranged at two ends of the active fiber to form a resonant cavity.
Optionally, the method further comprises: a seed light source for providing signal light.
Optionally, when the active optical fiber length is 0, a beam combiner for integrally outputting the signal light and the pump light is further included.
Optionally, the core of the active optical fiber is further used for transmitting the pump light leaked into the core, and the cladding of the active optical fiber is further used for transmitting the signal light leaked into the cladding.
Optionally, the active optical fiber is a double-clad or multi-clad active optical fiber, and the optical fiber output device comprises a double-clad or multi-clad first optical fiber and an output head; the cladding layer of the first optical fiber is used for transmitting the non-absorbed pump light in the active optical fiber and the signal light leaked into the cladding layer, and the fiber core of the first optical fiber is used for transmitting the signal light in the active optical fiber and the pump light leaked into the fiber core;
the numerical aperture NA of the fiber core of the active optical fiber and the numerical aperture NA of the fiber core of the first optical fiber are designed to control part of signal light to enter the cladding;
the numerical aperture NA of the cladding of the active optical fiber and the numerical aperture NA of the cladding of the first optical fiber are designed to control the partial pump light entering the core.
Optionally, the number of the cladding layers of the first optical fiber is greater than that of the cladding layers of the active optical fiber, and the active optical fiber and the first optical fiber are matched and arranged in a tapering or direct welding mode, so that cladding light transmitted in the cladding layers of the active optical fiber can enter a specific cladding layer of the first optical fiber according to design requirements.
Optionally, the optical fiber output device further comprises a stripper;
the stripper is used for stripping laser light transmitted in the outermost one or the outermost multi-layer cladding of the first optical fiber.
Optionally, the pump assembly comprises a plurality of pump light sources and a combiner.
Optionally, the plurality of pump light sources includes a plurality of pump light sources of different or same wavelength.
Optionally, the plurality of pump light sources includes: at least one of a semiconductor laser, a direct semiconductor laser, and a short wavelength fiber laser.
Optionally, the laser further comprises a control unit connected with the pumping assembly, wherein the control unit is used for controlling the output power of the pumping light so as to form composite laser spot outputs with different energy proportion profiles.
Optionally, the laser further comprises a control unit connected with the seed light source, wherein the control unit is used for adjusting the output power of the seed light source so as to form composite laser spot outputs with different energy proportion profiles.
The embodiment of the invention also discloses a multi-wavelength output laser processing system, which comprises: a laser as described above and a laser processing head connected to the optical fiber output device for directing the multi-wavelength composite laser output by the laser onto the workpiece to be processed.
Optionally, the laser processing head is a single fiber joint laser processing head, the fiber output device comprises a single fiber, and the multi-wavelength composite laser output by the laser is transmitted to the single fiber joint laser processing head through the single fiber.
The embodiment of the invention has the following advantages:
the laser of the embodiment of the invention comprises: a pump assembly for providing pump light, an active optical fiber and an optical fiber output device; the active optical fiber is used for partially absorbing the pump light to amplify the signal light, the fiber core of the active optical fiber is used for transmitting the signal light, and the cladding of the active optical fiber is used for transmitting the unabsorbed pump light; the optical fiber output device is used for transmitting the composite laser output by the active optical fiber. Compared with the prior art, on the one hand, the laser provided by the embodiment of the invention can enable the signal light and the pump light to be transmitted in a single optical fiber, realize multi-beam composite laser output, and does not need to be provided with two or more independent lasers, two independent laser output heads and other devices, so that the use of the devices is reduced, the cost can be reduced, and the size of the laser can be reduced. On the other hand, the laser of the embodiment of the invention does not need quartz to weld a plurality of optical fiber laser output optical fibers, has no requirement on the principle of the processing direction, and can simplify the processing technology.
Drawings
FIG. 1 is a block diagram of one laser embodiment of the present invention;
FIG. 2 is a schematic diagram showing the energy distribution of a composite laser in an actual state;
FIG. 3 is a schematic diagram of a composite laser energy distribution in an ideal state;
FIG. 4 is a schematic diagram of another composite laser energy distribution under ideal conditions;
FIG. 5 is a schematic diagram of another composite laser energy distribution under ideal conditions;
FIG. 6 is a schematic diagram of another composite laser energy distribution under ideal conditions;
FIG. 7 is a block diagram of a laser in one example;
fig. 8 is a block diagram of a laser in another example.
Detailed Description
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Referring to fig. 1, a block diagram of a first laser embodiment of the present invention is shown, which may specifically include:
a pump assembly 1 for providing pump light, an active optical fiber 2, an optical fiber output device 3;
the active optical fiber 2 is used for partially absorbing pump light and amplifying signal light, the fiber core of the active optical fiber 2 is used for transmitting the signal light, and the cladding of the active optical fiber 2 is used for transmitting the pump light which is not absorbed; the optical fiber output device 3 is used for transmitting the composite laser output by the active optical fiber 2.
The laser of the embodiment of the invention can be a laser with an all-fiber structure, namely devices in the laser are connected through optical fibers or are connected by self-contained optical fibers.
In the embodiment of the present invention, the absorption rate of the active optical fiber 2 may be greater than 0 and less than 15dB, and by setting the absorption rate of the active optical fiber 2 to be greater than 0 and less than 15dB, only a small portion of the pump light may be absorbed. In one example, the absorptivity of the active optical fiber 2 may be set to be greater than 0 and less than 10dB. In another example, the absorptivity of the active optical fiber 2 may be set to be greater than 0 and less than 8dB.
The absorption rate (dB) of the active optical fiber 2 is determined by the optical fiber length (m) and the absorption coefficient (dB/m) of the optical fiber itself, and thus the absorption rate can be adjusted by setting the length of the active optical fiber 2, and thus the active optical fiber length in the embodiment of the present invention is shorter than that of the existing optical fiber laser. In an embodiment of the present invention, the length of the active optical fiber 2 may be less than 50 meters. In one example, the length of the active optical fiber 2 may be less than 30 meters. In another example, the length of the active optical fiber 2 may be less than 20 meters. In another example, the length of the active optical fiber 2 may be less than 10 meters.
In embodiments of the present invention, the active optical fiber includes a core and a double or multi-clad layer.
In the embodiment of the invention, the fiber core of the active optical fiber is also used for transmitting the pumping light leaked into the fiber core, and the cladding of the active optical fiber is also used for transmitting the signal light leaked into the cladding.
In one example, the pump light and the signal light have different wavelengths, the signal light may have a center wavelength of 1030-2140nm, and the pump light may have a center wavelength of 915-1550nm. In another example, the center wavelength of the signal light may be 1080nm and the center wavelength of the pump light may be 915nm.
In the embodiment of the invention, the pump light and the signal light are transmitted in the same optical fiber, and the energy transmission of the fiber core and the cladding of the optical fiber forms a point-ring-shaped energy distribution mode. Dot-loop refers to a shape of one or more circles from a point of the center and around the center.
A typical point-ring type energy distribution composite laser is a straw hat type laser, and fig. 2 is a schematic diagram of a composite laser energy distribution in a practical state. The energy distribution of the laser at the outer edge part is flat-top distribution, and the energy distribution of the laser at the central part is Gaussian distribution or Gaussian-like distribution. A schematic diagram of the energy distribution of a composite laser in an ideal state is shown in fig. 3. The composite laser includes a central portion laser and an outer edge portion laser, and the central portion laser is mostly high-brightness signal light, and may be signal light output from the core of the active optical fiber 2. In practice, pump light leaking from the cladding of the active fiber may also be transmitted to the core. The power of the laser in the central part is related to the pump power and the active fiber parameters (including core diameter, numerical aperture NA, absorption, doping species, length).
The outer edge part of the laser is annular, the power density of the outer edge part of the laser is lower than that of the central part of the laser, the brightness of the outer edge part of the laser is also lower, and the outer edge part of the laser can be unabsorbed pump light transmitted from the cladding of the active optical fiber 2. In practice, the signal light leaking from the core of the active fiber 2 may also be transmitted to the cladding. The optical power of the outer laser is related to the pump power and the active fiber parameters (including core diameter, absorption, doping, length).
In an example of the embodiment of the invention, the energy distribution of the laser at the outer edge is flat-top, the beam energy uniformly acts on the surface of the workpiece, most of the beam energy is in heat conduction welding, the surface is smooth, but the energy density is low, the pinhole effect is not easy to form, and the penetration depth is shallow. The energy distribution of the laser in the central part is Gaussian or Gaussian-like, the energy is concentrated, small holes are easy to form, so that the penetration is large, and a keyhole is formed on the surface of a workpiece, but splashing is easy to form in the process, and the surface forming is influenced; the two wavelength light beams are combined to act on the workpiece, so that the advantages of the two wavelength light beams can be exerted, the certain weld depth is ensured, meanwhile, splashing is restrained, and the surface forming is improved.
In one example, the center portion laser and the outer edge portion laser may have different wavelengths, the center wavelength of the center portion laser may be 1030-2140nm, and the center wavelength of the outer edge portion laser may be 915-1550nm. In another example, the center wavelength of the center portion laser may be 1080nm and the center wavelength of the outer edge portion laser may be 915nm.
In one example, the central portion laser cross section is punctiform, square, circular, or quasi-circular.
In an embodiment of the present invention, the ratio of the laser power in the core of the active optical fiber 2 to the laser power in the cladding of the active optical fiber 2 may be set by the absorption rate of the active optical fiber 2. In practical use of the laser, since the active fiber parameters are fixed, the power of the center portion laser and the power of the edge laser can be adjusted by independently and continuously adjusting the pump power, thereby increasing or simultaneously decreasing the power of the center portion laser and the power of the edge laser.
In the existing fiber laser, the absorption rate of the active fiber is generally set to 15-20 dB, and the pump light is absorbed as much as possible to be converted into more signal light. The laser is also provided with a stripper connected between the active optical fiber and the optical fiber output device, the pump light which is not absorbed and the signal light outside the fiber core are lost by the stripper so as to keep the very clean signal light, and the light spot is generally similar to Gaussian light.
In the embodiment of the invention, the laser is not provided with the stripper for stripping the non-absorbed pump light and the signal light outside the fiber core, so that the non-absorbed pump light can be transmitted in the cladding to form the outer edge part of the output light spot.
Compared with the prior art, on the one hand, the laser provided by the embodiment of the invention can transmit signal light and pump light with different wavelengths in a single optical fiber, two or more independent lasers and two independent laser output heads and other devices are not needed, the use of the devices is reduced, the cost can be reduced, and the size of the laser can be reduced. On the other hand, the composite laser generated by the laser of the embodiment of the invention is the laser output by the same optical axis, quartz is not needed to weld a plurality of optical fiber laser output optical fibers, the principle of the processing direction is not required, and the processing technology can be simplified.
In the embodiment of the present invention, the active optical fiber 2 may be a double-clad or multi-clad active optical fiber, and the optical fiber output device 4 may include a double-clad or multi-clad first optical fiber and an output head.
In the embodiment of the present invention, the cladding of the first optical fiber is used for transmitting the pump light which is not absorbed in the active optical fiber 2, and the core of the first optical fiber is used for transmitting the signal light in the active optical fiber 2.
In the embodiment of the present invention, the cladding layer of the first optical fiber is used for transmitting the pump light which is not absorbed in the active optical fiber 2 and the signal light which leaks into the cladding layer, and the core of the first optical fiber is used for transmitting the signal light in the active optical fiber 2 and the pump light which leaks into the core.
The spot parameters (including spot size and spot shape) of the laser in the central portion of the composite laser are related to the core parameters of the active fiber 2 and the core parameters of the first fiber. Wherein the core parameters include a numerical aperture NA.
The numerical aperture of the core of the active optical fiber 2 and the numerical aperture of the core of the first optical fiber are designed to control a portion of the signal light to enter the cladding layer such that the laser transmission mode of the core of the active optical fiber 2 is the same as the laser transmission mode of the core of the first optical fiber.
The numerical aperture of the cladding of the active optical fiber 2 and the numerical aperture of the cladding of the first optical fiber are designed to control part of the pump light to enter the fiber core, so that the laser transmission module of the cladding of the active optical fiber 2 is identical to the laser transmission mode of the corresponding cladding in the first optical fiber.
The cladding of a multi-clad optical fiber may be divided into an inner cladding and an outer cladding. For a double-clad fiber, the cladding close to the fiber core is the inner cladding, and the cladding far from the fiber core is the outer cladding. For multi-clad optical fibers with more than three cladding layers, the cladding layer farthest from the optical fiber is an outer cladding layer, and the rest cladding layers are inner cladding layers. The overclad is typically a low index material that is not used to transmit laser light.
In the embodiment of the present invention, among the plurality of cladding layers of the active optical fiber 2, the cladding layers other than the outer cladding layer may be used to transmit the pump light that is not absorbed. Among the multiple claddings of the first optical fiber of the multiple cladding, the cladding other than the outer cladding is used for transmitting the pump light that is not absorbed.
In one example, the number of cladding layers of the active optical fiber 2 may be the same as the number of cladding layers of the first optical fiber.
In another example, the number of the cladding layers of the active optical fiber 2 may be smaller than the number of the cladding layers of the first optical fiber, in this example, the active optical fiber 2 and the first optical fiber are matched and arranged by tapering or direct fusion, so that the cladding light transmitted in the cladding layer of the active optical fiber 2 can enter the specific cladding layer of the first optical fiber according to the design requirement. For example, the active fiber is double clad and the first fiber is four clad. The laser light transmitted from the cladding of the active optical fiber 2 may be diffused into at least one cladding of the first optical fiber for transmission. Specifically, the active optical fiber and the first optical fiber can be subjected to independent tapering treatment through the optical fiber cladding or simultaneous tapering of the cladding and the fiber core to match the fiber size and NA setting, so that pump light transmitted in the active optical fiber cladding can enter at least one cladding of the first optical fiber.
In an embodiment of the present invention, the optical fiber output device 4 may further include a stripper; the stripper is used for stripping the laser transmitted in the outermost layer or the outermost multi-layer cladding of the first optical fiber, and particularly can strip unnecessary cladding light according to actual needs.
Another schematic diagram of the energy distribution of the composite laser in the ideal state is shown in fig. 4. The composite laser of the spot ring energy distribution as shown may also be referred to as a straw hat laser, comprising a center portion laser and an outer edge portion laser of an annulus, the center portion laser having a power greater than the edge portion laser power. The central portion laser and the outer edge portion laser may have a recess therebetween, the recess being due to the absence or low energy therein (which provides only stray radiation or no laser radiation at all). The concave part and the outer edge part of the laser light are annular energy distribution.
In particular, the recess may be created by fitting a particular fiber product, such as a standard QBH enabled fiber. For example, a portion of the QBH enabled fiber is an F-doped low index layer, and dishing occurs in this portion.
Another schematic diagram of the energy distribution of the composite laser in the ideal state is shown in fig. 5. The composite laser with the dot-loop energy distribution as shown in the figure can also be called as straw hat laser, and comprises a central part laser and an outer edge part laser of an annular belt, wherein the power of the central part laser is smaller than that of the edge part laser, and a concave part is arranged between the central part laser and the outer edge part laser. The ratio of the power of the center portion laser to the power of the edge portion laser can be set by adjusting the absorption rate and the pump light power of the active optical fiber 2.
Another schematic diagram of the energy distribution of the composite laser in the ideal state is shown in fig. 6. Comprising a central portion laser, two ring edge lasers and two concave ring zones.
In an embodiment of the present invention, the pump assembly 1 may include a plurality of pump light sources 11 and beam combiners 12.
The combiner 12 may be a high power n+1:1 beam combiner comprising a plurality of input fibers and an output fiber, each pump light source 11 being connectable to one input fiber, the pump light outputted by the plurality of pump light sources being coupled by the beam combiner 12 and outputted from the output fiber.
The pump light source 11 may be a semiconductor pump light source, or may be any laser light source output by an optical fiber. For example, the plurality of pump light sources 11 may include at least one of semiconductor laser light, direct semiconductor laser light, and short wavelength fiber laser light. For example, the multiple pump light sources 11 may be all semiconductor lasers, or part of the pump light sources may be direct semiconductor lasers, and the rest of the pump light sources may be short wavelength fiber lasers. The kind of the pumping light source can be set according to actual needs.
In the embodiment of the present invention, the wavelength of the laser light of the central portion and the wavelength of the laser light of the edge portion of the composite laser light may be set according to the wavelength of the pump light source 11 and the doping element of the active optical fiber 2. The doping elements may include ytterbium (Yb), erbium (Er), thulium (Tm), and the like.
For example, the pumping wavelength is 915nm, the active optical fiber is doped with Yb, the wavelength of the signal light can be in the range of 1030-1090 nm, the wavelength of the laser in the central part can be in the range of 1030-1090 nm, the wavelength bandwidth is in the range of 0.5nm to 20nm, and the power is not less than 100W; the edge portion laser wavelength included 915nm.
The plurality of pump light sources 11 may be pump light sources of the same wavelength or pump light sources of different wavelengths. Using pump light sources 11 of different wavelengths, a composite laser of different wavelength combinations can be generated.
In an embodiment of the present invention, the laser may further include a control unit connected to the pump assembly, where the control unit is configured to control the output power of the pump light, so as to form a composite laser spot output with different energy ratio profiles.
For example, the control unit may be connected to each of the pump light sources 11, and may control the pump light power output from each of the pump light sources 11. For example, the control unit controls the partial pump light source 11 to be turned on or off, and the control unit controls the partial pump light source 11 to increase or decrease the output pump light power.
In an embodiment of the present invention, the laser may further include: a second optical fiber 4 connected between the active optical fiber 2 and the optical fiber output device 3, and a third optical fiber 5 connected between the combiner 12 and the active optical fiber 2.
The second optical fiber 4 and the third optical fiber 5 may be double-clad or multi-clad optical fibers, the second optical fiber 4 being matched with the first optical fibers of the active optical fiber 2 and the optical fiber output device 3. In particular, the core of the second optical fiber 4 may be used for transmitting signal light, and the cladding of the second optical fiber 4 may be used for transmitting unabsorbed pump light. Specifically, the core of the second optical fiber 4 is further used for transmitting the pump light leaking into the core, and the cladding of the second optical fiber 4 is further used for transmitting the signal light leaking into the cladding.
In the embodiment of the present invention, the spot parameters (including the spot shape and the spot size) of the outer edge part laser of the composite laser are related to the cladding diameters and numerical aperture NA of the second optical fiber 4 and the first optical fiber, and the beam combiner parameters.
The combiner parameters refer to process parameters of a combiner, and when the combiner is manufactured, the combiner is manufactured according to the input optical fiber and the output optical fiber to be connected, and the manufacturing process parameters are set for the input optical fiber and the output optical fiber to be connected. In the embodiment of the present invention, the combiner parameter may be set according to the input optical fiber connected to the pump light source and the third optical fiber 5, so that the effect of the third optical fiber 5 on the laser output laser may be attributed to the combiner parameter, and the combiner parameter may include the parameter of the input optical fiber of the pump light source and the parameter of the third optical fiber 5.
In practice, the cladding diameter, numerical aperture NA, beam combiner parameters and first fiber parameters of the second fiber 4 may be set according to actual needs, so as to set the spot parameters of the outer edge part of the composite laser output by the laser. The second optical fiber 4 may be provided with the same fiber parameters as the third optical fiber 5.
In one example of an embodiment of the present invention, the laser may further include: and the fiber Bragg gratings FBG6 are arranged at two ends of the active fiber to form a resonant cavity. Referring to fig. 7, a block diagram of a laser in one example is shown.
The fiber bragg grating FBG6 may include an HR (High Reflector) FBG and an OC (Out Coupler) FBG, wherein the HR FBG is disposed between the pump assembly 1 and the active fiber 2, the OC FBG is disposed between the active fiber 2 and the fiber output device 3, and the HR FBG and the OC FBG constitute a resonant cavity. The pump light is transmitted in the cavity, and a part of the pump light is absorbed by the active optical fiber 2, thereby generating signal light, and the other part of the pump light is output from the cavity. The optical fiber output device 3 outputs laser light output from the resonator.
In another example of the embodiment of the present invention, the laser may further include: a seed light source for providing signal light. Referring to fig. 8, a block diagram of a laser in another example is shown. The signal light output by the seed light source 7 and the pump light output by the pump assembly 1 are transmitted and coupled to the active optical fiber 2, and the active optical fiber 2 absorbs the pump light to amplify the signal light.
The laser that supplies the signal light through the seed light source may be referred to as a MOPA (Master Oscillator Power-Amplifier, power Amplifier of the master oscillator) laser.
In this example, each of the pump light source 11 and the seed light source 7 may be connected to one input optical fiber of the beam combiner 12, and the pump light outputted from the plurality of pump light sources and the signal outputted from the seed light source 7 are optically coupled by the beam combiner 12 and outputted from the output optical fiber of the beam combiner 12.
The pump light and the signal light output from the output fiber of the beam combiner 12 may be received by the active fiber 2, and the pump light is absorbed by the active fiber 2 to amplify the signal light.
In an alternative embodiment, the length of the active optical fiber may be set to 0, that is, a structure in which the signal light and the pump light are directly output by the beam combiner is formed, and the final light spot output characteristic is selected by different matching of the output optical fiber and the beam combiner.
The seed light source 7 may comprise a single resonant cavity fiber laser, or a fiber-coupled thin-sheet laser, or a diode-pumped solid-state laser (e.g., nd-YAG laser), or a semiconductor laser.
In this example, the laser further includes a control unit coupled to the seed light source for adjusting the output power of the seed light source to form a composite laser spot output of different energy ratio profiles.
In this example, the wavelength of the composite laser center portion laser light and the wavelength of the edge portion laser light may be set according to the wavelength of the seed light source 7, the wavelength of the pump light source 11, and the doping element of the active optical fiber 2.
The power of the laser in the central part of the composite laser is related to the seed light source power, the pump power and the active fiber parameters (including core diameter, numerical aperture NA, absorptivity, doping substance, length).
When the laser is actually used, as the parameters of the active optical fiber are fixed, the power of the laser at the central part and the power of the laser at the edge part can be adjusted by independently and continuously adjusting the power of the seed light source or the pump power, so that the light spot output with different energy proportion profiles is formed.
The invention also discloses an embodiment of the multi-wavelength output laser processing system, wherein the multi-wavelength output laser processing system can comprise: a laser and a laser processing head, the laser comprising:
the device comprises a pumping assembly for providing pumping light, an active optical fiber and an optical fiber output device;
the active optical fiber is used for partially absorbing the pump light and amplifying the signal light, the fiber core of the active optical fiber is used for transmitting the signal light, and the cladding of the active optical fiber is used for transmitting the pump light which is not absorbed;
the optical fiber output device is used for transmitting the composite laser output by the active optical fiber;
the laser processing head is connected with the optical fiber output device and is used for guiding the multi-wavelength composite laser output by the laser to a workpiece to be processed.
The laser in this embodiment may be referred to the above embodiments, and will not be described herein. In the embodiment of the invention, the laser processing head can be a single-fiber joint laser processing head, the optical fiber output device comprises a single fiber, and the multi-wavelength composite laser output by the laser is transmitted to the single-fiber joint laser processing head through the single fiber. The single optical fiber may be the first optical fiber described above.
The multi-wavelength output laser processing system of the present embodiment may be used for laser welding, laser cladding, or other laser applications. The laser head outputs two beams of laser with different wavelengths at the central part and the outer edge part, so that the outer edge part laser can form a flat appearance on the surface of a processed workpiece, and the central part laser can form a weld joint with larger depth. Specifically, the multi-wavelength output laser processing system of the present embodiment can be used for laser continuous welding.
Compared with the prior art, on the one hand, the multi-wavelength output laser processing system of the embodiment of the invention does not need to be provided with two or more independent lasers, two independent laser output heads and other devices, thereby reducing the use of the devices, reducing the cost and reducing the size of the lasers. On the other hand, the multi-wavelength output laser processing system of the embodiment of the invention does not need quartz to weld a plurality of optical fiber laser output optical fibers, has no requirement on the processing direction principle, and can simplify the processing technology.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the embodiments of the invention.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or terminal device comprising the element.
The foregoing has described in detail a laser and a multi-wavelength output laser processing system provided by the present invention, and specific examples have been provided herein to illustrate the principles and embodiments of the present invention, the above examples being provided only to assist in understanding the methods of the present invention and the core ideas thereof; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (18)
1. A laser, comprising:
a pump assembly for providing pump light, an active optical fiber and an optical fiber output device;
the active optical fiber is used for partially absorbing the pump light and amplifying the signal light, the fiber core of the active optical fiber is used for transmitting the signal light, and the cladding of the active optical fiber is used for transmitting the pump light which is not absorbed;
the optical fiber output device is used for transmitting the composite laser output by the active optical fiber;
the active optical fiber is double-clad or multi-clad active optical fiber, and the optical fiber output device comprises a double-clad or multi-clad first optical fiber and an output head; the cladding layer of the first optical fiber is used for transmitting the non-absorbed pump light in the active optical fiber and the signal light leaked into the cladding layer, and the fiber core of the first optical fiber is used for transmitting the signal light in the active optical fiber and the pump light leaked into the fiber core;
the numerical aperture NA of the fiber core of the active optical fiber and the numerical aperture NA of the fiber core of the first optical fiber are designed to control part of signal light to enter the cladding;
the numerical aperture NA of the cladding of the active optical fiber and the numerical aperture NA of the cladding of the first optical fiber are designed to control the partial pump light entering the core.
2. The laser of claim 1, wherein the active fiber has an absorptivity of greater than 0 and less than 15dB.
3. The laser of claim 1, wherein the active fiber has an absorptivity of greater than 0 and less than 10dB.
4. The laser of claim 1, wherein the active optical fiber has a length of less than 50 meters.
5. The laser of claim 1, wherein the active optical fiber has a length of less than 20 meters.
6. The laser of claim 1, wherein the active optical fiber has a length of less than 10 meters.
7. The laser of claim 1, further comprising: and the fiber Bragg gratings FBG are arranged at two ends of the active fiber to form a resonant cavity.
8. The laser of claim 1, further comprising: a seed light source for providing signal light.
9. The laser of claim 1, wherein the core of the active fiber is further configured to transmit pump light that leaks into the core, and wherein the cladding of the active fiber is further configured to transmit signal light that leaks into the cladding.
10. The laser according to claim 1, wherein the number of the cladding layers of the first optical fiber is larger than the number of the cladding layers of the active optical fiber, and the active optical fiber and the first optical fiber are matched and arranged in a tapering or direct welding mode, so that cladding light transmitted in the cladding layers of the active optical fiber can enter a specific cladding layer of the first optical fiber according to design requirements.
11. The laser of claim 10, wherein the fiber output device further comprises a stripper;
the stripper is used for stripping laser light transmitted in the outermost one or the outermost multi-layer cladding of the first optical fiber.
12. The laser of claim 1, wherein the pump assembly comprises a plurality of pump light sources and a combiner.
13. The laser of claim 12, wherein the plurality of pump light sources comprises a plurality of pump light sources of different or same wavelength.
14. The laser of claim 12, wherein the plurality of pump light sources comprises: at least one of a semiconductor laser, a direct semiconductor laser, and a short wavelength fiber laser.
15. The laser of claim 1, further comprising a control unit coupled to the pump assembly, the control unit configured to control the output power of the pump light to form a composite laser spot output of different energy ratio profiles.
16. The laser of claim 8, further comprising a control unit coupled to the seed light source, the control unit configured to adjust the output power of the seed light source to form a composite laser spot output of different energy ratio profiles.
17. A multi-wavelength output laser processing system, comprising: a laser as claimed in any one of claims 1 to 16 and a laser processing head connected to the optical fibre output device for directing the multi-wavelength composite laser output by the laser onto a workpiece to be processed.
18. The multi-wavelength output laser processing system of claim 17, wherein the laser processing head is a single fiber joint laser processing head, the fiber output device comprises a single fiber, and the multi-wavelength composite laser output by the laser is transmitted to the single fiber joint laser processing head through the single fiber.
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| CN202010450858.3A CN113794091B (en) | 2020-05-25 | 2020-05-25 | Laser and multi-wavelength output laser processing system |
| PCT/CN2020/132016 WO2021238120A1 (en) | 2020-05-25 | 2020-11-27 | Laser and multi-wavelength output laser processing system |
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| CN116482800B (en) * | 2023-06-20 | 2023-10-03 | 深圳市创鑫激光股份有限公司 | Special optical fiber, laser and laser processing system |
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| US6275250B1 (en) * | 1998-05-26 | 2001-08-14 | Sdl, Inc. | Fiber gain medium marking system pumped or seeded by a modulated laser diode source and method of energy control |
| US6882664B2 (en) * | 2002-02-28 | 2005-04-19 | Lucent Technologies Inc. | Laser with internally coupled pump source |
| JP4784406B2 (en) * | 2006-06-13 | 2011-10-05 | 住友電気工業株式会社 | Fiber laser apparatus and laser processing method |
| WO2012053045A1 (en) * | 2010-10-18 | 2012-04-26 | 新日本製鐵株式会社 | Laser apparatus and laser processing apparatus provided with same |
| GB2511043B (en) * | 2013-02-20 | 2016-03-23 | Fianium Ltd | A supercontinuum source |
| CN103311786B (en) * | 2013-06-19 | 2015-11-18 | 深圳大学 | A kind of erbium-ytterbium co-doped fiber amplifier suppressing Yb-ASE |
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| CN107623246B (en) * | 2016-07-14 | 2020-11-17 | 中国兵器装备研究院 | Fiber core co-band pumping fiber laser |
| EP3551372B1 (en) * | 2016-12-08 | 2022-09-14 | Corelase OY | Laser processing apparatus and method of cutting a workpiece with a laser beam |
| CN111149262B (en) * | 2017-09-29 | 2021-09-28 | 株式会社藤仓 | Fiber laser system and control method thereof |
| KR102418512B1 (en) * | 2017-12-29 | 2022-07-07 | 코렐라스 오와이 | Laser processing apparatus and method |
| CN110187437B (en) * | 2019-06-27 | 2023-07-07 | 深圳市创鑫激光股份有限公司 | Three-cladding optical fiber, pump beam combiner, fiber grating and fiber laser |
| CN211404995U (en) * | 2020-06-19 | 2020-09-01 | 深圳市创鑫激光股份有限公司 | Multi-wavelength all-fiber laser and processing equipment thereof |
| CN211361033U (en) * | 2020-06-19 | 2020-08-28 | 深圳市创鑫激光股份有限公司 | Multi-wavelength high-power laser processing system |
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