SUMMERY OF THE UTILITY MODEL
In view of the above, it is necessary to provide a fiber laser for solving the problem that the laser beam reflected back to the inside of the gain fiber of the laser affects the operation inside the laser.
A fiber laser comprising: the device comprises a pumping module, a resonant cavity, a first gain fiber, a second gain fiber, a first cladding optical stripper and a power output head; the pumping module injects pumping light to the input end of the resonant cavity; the first gain fiber is arranged in the resonant cavity; the output end of the resonant cavity is coupled with one end of the second gain fiber; the resonant cavity outputs signal seed light to the second gain optical fiber; a first transition optical fiber is arranged in the first cladding optical stripper; the power output head comprises an energy transmission optical fiber; the second gain fiber is in butt joint with the energy transmission fiber through the first transition fiber; the first transition optical fiber is coupled with the energy transmission optical fiber through a fusion point.
The optical fiber laser is characterized in that the first transition optical fiber and the energy transmission optical fiber are welded, and the core diameter of the energy transmission optical fiber is larger than that of the first transition optical fiber, so most of returning light in the fiber core of the energy transmission optical fiber enters the cladding of the first transition optical fiber and is stripped by the first cladding stripper; because the pump light energy in the second gain fiber is lower, and the resonant cavity adopts forward pumping, the chance that the return light entering the fiber core of the first transition fiber is amplified reversely in the second gain fiber or the resonant cavity is reduced, thereby avoiding the influence of the return light on the operation of the resonant cavity and improving the stability of the operation of the high-power fiber laser.
In one embodiment, the power output head further comprises a second cladding stripper disposed on the energy conducting fiber; thereby reducing the intensity of the return light entering the cladding of the first transition fiber.
In one embodiment, the pumping module comprises a pumping beam combiner connected with the resonant cavity and a plurality of pumping sources connected with the pumping beam combiner; the pumping beam combiner is provided with a plurality of pumping fibers and output fibers; the pump sources are coupled with pump fibers of the pump combiner, and pump light is injected into the pump combiner from each pump source through the pump fibers; the combined pump light is output to the resonant cavity through an output fiber of the pump beam combiner; therefore, a plurality of pumping sources can be utilized to provide pumping light to the resonant cavity, and the energy density of the signal light is improved.
In one embodiment, the device further comprises an indication module connected with the pumping module; the pumping beam combiner is also provided with a central fiber; the indicating module comprises an indicating light source for injecting indicating light into the central fiber; thereby facilitating identification of the transmission path after the signal light is output.
In one embodiment, the indication module further comprises a narrow-band filter disposed between the indication light source and the central fiber of the pump combiner; one end of the narrow-band filter is coupled with the indicating light source, and the other end of the narrow-band filter is coupled with the central fiber of the pumping beam combiner; thereby avoiding the pointing light source being affected by the returning light.
In one embodiment, the indication light source generates the indication light of red light, blue light or green light; thereby facilitating the visual identification of operators.
In one embodiment, the pump fibers of the pump combiner and the pump sources have a one-to-one correspondence.
In one embodiment, the resonant cavity comprises a first grating and a second grating; an output fiber of the pump beam combiner is coupled with one end of the first grating, and the other end of the first grating is coupled with one end of the first gain fiber; the other end of the first gain fiber is coupled with one end of the second grating; the other end of the second grating is coupled with one end of the second gain fiber.
In one embodiment, the first transition fiber is a double-clad fiber; thereby facilitating the derivation of the return light in the cladding of the first transition fiber.
In one embodiment, the core diameter of the energy transmission optical fiber is 50um to 100 um; thereby ensuring the width of the gap cut by the fiber laser.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be described more fully below. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Referring to fig. 1 and 2, a fiber laser 100 according to an embodiment of the present invention is used for generating laser output. The fiber laser 100 comprises a pumping module 20, a resonant cavity 30, a first gain fiber 40, a second gain fiber 50, a first cladding stripper 60, and a power output head 70; the pumping module 20 injects pumping light to the input end of the resonant cavity 30; a first gain fiber 40 is disposed within the resonant cavity 30; the output end of the resonant cavity 30 is coupled to one end of a second gain fiber 50; the resonant cavity 30 outputs the signal seed light to the second gain fiber 50; the first clad optical stripper 60 is provided with a first transition optical fiber 61; the power output head 70 comprises an energy-transmitting fiber 71; the second gain fiber 50 is butted with the energy transmission fiber 71 through a first transition fiber 61; the first transition optical fiber 61 and the energy transmission optical fiber 71 are coupled by a fusion point 601.
By fusion-splicing the first transition optical fiber 61 and the energy transmission optical fiber 71, and the core diameter of the energy transmission optical fiber 71 is larger than that of the first transition optical fiber 61, most of the returning light 900 in the core 711 of the energy transmission optical fiber 71 enters the cladding 612 of the first transition optical fiber 61 and is stripped by the first cladding stripper 60; because the pump light energy in the second gain fiber 50 is low, and the resonant cavity 30 adopts forward pumping, the chance that the return light 900 entering the fiber core 611 of the first transition fiber 61 is reversely amplified in the second gain fiber 50 or the resonant cavity 30 is reduced, thereby avoiding the influence of the return light 900 on the operation of the resonant cavity 30, and improving the stability of the operation of the high-power fiber laser 100.
The pumping module 20 comprises a pumping beam combiner 21 connected with the resonant cavity 30 and a plurality of pumping sources 22 connected with the pumping beam combiner 21; the pumping beam combiner 21 is provided with a plurality of pumping fibers and output fibers; the pump sources 22 are coupled with the pump fibers of the pump combiner 21, and each pump source 22 injects pump light into the pump combiner 21 through the pump fibers; the combined pump light is output to the resonant cavity 30 through the output fiber of the pump beam combiner 21. The pump fibers of the pump combiner 21 and the pump sources 22 are in one-to-one correspondence.
The resonant cavity 30 includes a first grating 31 and a second grating 32; the output fiber of the pump beam combiner 21 is coupled with one end of the first grating 31, and the other end of the first grating 31 is coupled with one end of the first gain fiber 40; the other end of the first gain fiber 40 is coupled to one end of the second grating 32; the other end of the second grating 32 is coupled to one end of a second gain fiber 50.
Specifically, the first gain fiber 40 absorbs the pump light in a certain proportion to generate high-quality signal seed light, and the reflectivity of the first grating 31 to the signal seed light is greater than that of the second grating 32 to the signal seed light; part of the signal seed light in the first gain fiber 40 is transmitted through the second grating 32 and output to the second gain fiber 50, and meanwhile, part of the pump light in the first gain fiber 40 is transmitted through the second grating 32 and output to the second gain fiber 50; the pump light is absorbed in the second gain fiber 50 in a large proportion, and the signal seed light is amplified to a predetermined power and then sequentially output through the first cladding light stripper 60 and the power output head 70; a small amount of the pump light in the cladding of the second gain fiber 50 is stripped by the first cladding stripper 60; another portion of the signal seed light in the first gain fiber 40 is reflected back to the first gain fiber 40 via the second grating 32 and further amplified in the first gain fiber 40. Specifically, the first and second gain fibers 40 and 50 are rare-earth ion-doped fibers.
The first transition fiber 61 is a double clad fiber.
The power output head 70 further comprises a second cladding stripper 72 disposed on the energy-transmitting fiber 71; specifically, the return light 900 entering the cladding 712 of the energy transmitting fiber 71 is stripped by the second cladding stripper 72 during the transmission along the cladding 712 of the energy transmitting fiber 71; since the first transition optical fiber 61 and the energy transmission optical fiber 71 are coupled by the fusion point 601, and the outer diameter of the energy transmission optical fiber 71 is larger than that of the first transition optical fiber 61, the return light 900 entering the cladding 612 of the first transition optical fiber 61 is reduced and the return light 900 is prevented from being emitted from the fusion point 601 by the second cladding stripper 72.
The core diameter of the energy transmission fiber 71 is 50um to 100 um.
The fiber laser 100 further includes an indication module 80 connected to the pumping module 20; the pumping beam combiner 21 is also provided with a central fiber; the indicating module 80 includes an indicating light source 81 injecting indicating light to the central fiber; the indication light source 81 generates visible indication light, the indication light is output by the pump beam combiner 21, the resonant cavity 30, the first gain fiber 40, the second gain fiber 50, the first cladding light stripper 60 and the power output head 70 in sequence, and the visible indication light can be used for indicating a transmission path after signal light is output so as to adjust a subsequent light path; meanwhile, the maintenance and repair are convenient when the optical path is damaged.
The indication module 80 further comprises a narrow band filter 82 disposed between the indication light source 81 and the central fiber of the pump combiner 21; one end of the narrow-band filter 82 is coupled with the indication light source 81, and the other end of the narrow-band filter 82 is coupled with the central fiber of the pump combiner 21; the indication light generated by the indication light source 81 enters the pumping module 20 through the narrow band filter 82, and specifically, the indication light source 81 and the narrow band filter 82 are connected through an optical fiber; the return light 900 entering the core of the second gain fiber 50 is guided along the second gain fiber 50, the first gain fiber 40, and the center fiber of the pump combiner 21, and the return light 900 is filtered when being guided to the narrow band filter 82.
Further, in order to conveniently derive the cladding light in the central fiber of the pump combiner 21, the indication module 80 further includes a second transition fiber 83, the other end of the narrow-band filter 82 is coupled with the central fiber of the pump combiner 21 through the second transition fiber 83, and the second transition fiber 83 is a double-cladding fiber; so that the cladding light in the central fiber of the pump combiner 21 is conducted onto the second transition fiber 83 and filtered out by the narrow band filter 82. The indicating light source 81 generates indicating light of red, blue, or green.
Referring to fig. 2, specifically, when the fiber laser 100 processes a material, a part of the return light 900 generated by the signal light and the material enters the cladding 712 of the energy transmission fiber 71, and a part of the return light enters the core 711 of the energy transmission fiber 71; the return light 900 entering the cladding 712 of the energy-transmitting fiber 71 is stripped by the second cladding stripper 72; since the core 711 of the energy transmission fiber 71 has a larger diameter than the core 611 of the first transition fiber 61, most of the return light 900 in the core 711 of the energy transmission fiber 71 enters the cladding 612 of the first transition fiber 61 at the fusion-splicing point 601.
In the embodiment, the first transition fiber and the energy transmission fiber are welded, and the core diameter of the energy transmission fiber is larger than that of the first transition fiber, so most of returning light in the fiber core of the energy transmission fiber enters the cladding of the first transition fiber and is stripped by the first cladding stripper; because the pump light energy in the second gain fiber is lower, and the resonant cavity adopts forward pumping, the chance that the return light entering the fiber core of the first transition fiber is amplified reversely in the second gain fiber or the resonant cavity is reduced, thereby avoiding the influence of the return light on the operation of the resonant cavity and improving the stability of the operation of the high-power fiber laser.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.