Waste light receiving device of optical fiber cladding light stripper

Abstract

The invention discloses an optical fiber cladding light stripper waste light receiving device which comprises a heat conduction base and an upper cover shell, the upper cover shell and the heat conduction base are fixedly connected in an up-and-down covering mode, and a photo-thermal conversion cavity is defined by the interior of the upper cover shell and the heat conduction base. A stripping section of a double-cladding optical fiber of the optical fiber cladding light stripper is arranged in the photothermal conversion cavity, and the two ends of a glass tube of the optical fiber cladding light stripper are installed and positioned through the heat conduction base and the upper cover shell. The waste light receiving device can reduce the number of times that waste light passes through the cladding light stripper again, the waste light is prevented from repeatedly and continuously heating the stripping section optical fiber, the risk that the optical fiber in the glass tube is burnt down is reduced, meanwhile, the photo-thermal conversion process can be evenly carried out in the whole photo-thermal conversion cavity, and the service life of the photo-thermal conversion cavity is prolonged. Local overheating caused by too fast heat accumulation at the front ends of the heat conduction base and the upper cover shell can be effectively avoided, and therefore the risk that the front end of the stripper is burnt down is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber lasers, and in particular to a waste light receiving device of an optical fiber cladding light stripper. Background Art

[0002] Fiber lasers have the advantages of good beam quality, high electro-optical conversion efficiency, compact structure, strong stability, and convenient thermal management. They are widely used in advanced industrial processing and manufacturing, national defense, laser communications, wireless energy transmission, medical imaging and other fields.

[0003] Fiber cladding light strippers are important components of fiber lasers. They are used to strip the unabsorbed pump light in the fiber cladding, the return light generated by reflection, and the high-order mode signal light generated by factors such as nonlinear effects. They have a significant impact on the operating stability and beam quality of the fiber laser. At present, the production of cladding light strippers generally uses hydrofluoric acid corrosion, frosting corrosion, mechanical polishing and other methods to roughen and thin the fiber cladding to extract the waste light in the cladding. The optical fiber that has been treated in the above way will lose the coating layer or even a certain thickness of the cladding, making this section of the optical fiber more fragile. The current common treatment solution is to encapsulate this section of the treated optical fiber in a glass tube for protection.

[0004] During the operation of the laser, a large amount of waste light in the cladding is concentrated on the very short section of optical fiber stripper and exported. For high-power fiber lasers of kilowatts or even tens of thousands of watts, the waste light power stripped on this section of optical fiber can reach hundreds of watts or even kilowatts. If it is allowed to scatter into the laser, it will quickly generate a lot of heat, thus burning the optical fiber and even other devices. At present, independent metal shell packaging is generally used to receive waste light, and the light-heat conversion is realized by using the metal's absorption of light, and the accumulated heat is exported through the water cooling or air cooling channel in the metal shell.

[0005] At present, aluminum, copper, iron and other metal materials are commonly used to make heat-conducting shells. These metal materials have low absorption efficiency for light in the range of 0.9μm-1.1μm. The waste light that is not absorbed in time will be repeatedly refracted in the packaging shell, and the fiber optic cladding light stripper, which has become fragile due to treatment, will be repeatedly and continuously heated. This continuous heat accumulation will increase the risk of burning the cladding light stripper. In addition, the cladding light strippers on the market currently generally have the problem of uneven cladding light stripping, that is, most of the cladding light pours out at the front end of the stripper, which will cause the heat at the front end of the metal packaging shell of the cladding light stripper to accumulate too quickly, increasing the cooling burden at this position, making it difficult for the cooling system to timely remove the accumulated heat at this position, resulting in uneven temperature distribution inside the metal package, increasing the risk of burning the front end of the stripper. Therefore, there is a need for a waste light receiving device for an optical fiber cladding light stripper that can efficiently and evenly receive cladding waste light and remove accumulated heat, while having a simple and compact structure. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a waste light receiving device for an optical fiber cladding light stripper, which can guide the waste light portion output from the front end of the stripper to the middle part of the photothermal conversion cavity or even between the rear fins for absorption, so that the photothermal conversion process is carried out evenly in the entire photothermal conversion cavity, and can effectively avoid local overheating caused by excessive heat accumulation at the front end of the thermal conductive base and the upper cover shell, thereby reducing the risk of burning of the front end of the stripper.

[0007] A waste light receiving device for an optical fiber cladding light stripper comprises a heat-conducting base and an upper cover shell, wherein the upper cover shell is fixedly connected to the heat-conducting base by covering it from top to bottom and enclosing the inside to form a photothermal conversion cavity, wherein an internal photothermal conversion fin group is arranged in the photothermal heat exchange cavity, and the stripping section of the double-clad optical fiber of the optical fiber cladding light stripper is placed in the photothermal conversion cavity, and the two ends of the glass tube of the optical fiber cladding light stripper are installed and positioned by the heat-conducting base and the upper cover shell.

[0008] As a preferred embodiment of the above technical solution, a photothermal conversion groove is provided on the top surface of the heat conductive base along the length direction, a photothermal conversion fin group is vertically provided in the photothermal conversion groove, a fixing groove is symmetrically provided on the top surface of the heat conductive base at both ends of the photothermal conversion groove, and a heat conductive card groove is symmetrically provided on the top surface of the heat conductive base parallel to the photothermal conversion groove.

[0009] As a preferred embodiment of the above technical solution, the bottom surface of the upper cover shell is provided with two photothermal conversion grooves along the length direction, and two photothermal conversion fin groups are vertically provided in the two photothermal conversion grooves. Two fixing grooves are symmetrically provided on the bottom surface of the upper cover shell at both ends of the two photothermal conversion grooves, and thermal conductive fins adapted to the thermal conductive card slots are symmetrically provided on the bottom surface of the upper cover shell parallel to the two photothermal conversion grooves.

[0010] As a preferred embodiment of the above technical solution, the photothermal conversion fin group 1 and the photothermal conversion fin group 2 have the same structure and are arranged opposite to each other, and together constitute the inner photothermal conversion fin group.

[0011] As a preferred embodiment of the above technical solution, the photothermal conversion fin group 1 and the photothermal conversion fin group 2 are both composed of multiple parallel fin blocks, and the distance between two adjacent fin blocks and the height of the fin blocks gradually decrease along the laser transmission direction.

[0012] As a preferred embodiment of the above technical solution, the lower end surface and the upper end surface of the fin single block arranged opposite to each other are provided with notches of the same size, the length of the notch gradually decreases along the laser transmission direction, and the depth gradually increases along the laser transmission direction.

[0013] As a preferred embodiment of the above technical solution, through holes for connecting the second fixing groove and the outside of the upper cover shell are symmetrically provided on the bottom surface of the upper cover shell.

[0014] As a preferred embodiment of the above technical solution, an external light-to-heat conversion fin group is provided outside the upper cover shell.

[0015] As a preferred embodiment of the above technical solution, a heat dissipation channel is provided inside the heat-conducting base and / or the upper cover shell, and the heat dissipation channel adopts a water cooling channel or an air cooling channel.

[0016] As a preferred embodiment of the above technical solution, the heat conductive base is integrated on a water cooling plate of the fiber laser and shares a cooling system with the fiber laser.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. In the waste light receiving device of the optical fiber cladding light stripper, the heat-conducting base and the upper cover shell form a light-to-heat conversion cavity. The fin group structure inside the cavity can make the stripped cladding waste light produce multiple refractions between the fins, reducing the number of times the waste light passes through the cladding light stripper again. This structure increases the contact area between the waste light and the cavity to improve the light-to-heat conversion efficiency, while avoiding the problem of repeated and continuous heating of the stripped section optical fiber due to the inability to convert the exported waste light into heat in time, which can significantly reduce the risk of burning the optical fiber inside the glass tube.

[0018] 2. In the waste light receiving device of the optical fiber cladding light stripper, the fin group inside the photothermal conversion cavity has a special arrangement rule along the signal laser transmission direction in the optical fiber core, and the shape of the fin also changes along the laser transmission direction. This fin shape and arrangement setting can guide the waste light from the front end of the stripper to the middle and even rear fins of the photothermal conversion cavity for absorption, so that the photothermal conversion process is carried out evenly in the entire photothermal conversion cavity. At present, optical fiber cladding light strippers made by various methods generally have a certain degree of uneven stripping problem. The light energy stripped from the front end of the stripper is often greater than that from the rear end. The structure proposed by the present invention can avoid local overheating caused by excessive heat accumulation at the front end of the heat-conducting base and the upper cover shell, thereby reducing the risk of burning the front end of the stripper. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the waste light receiving device of the optical fiber cladding light stripper; Figure 2 It is a basic structural diagram of an optical fiber cladding light stripper; Figure 3 It is a schematic diagram of the overall structure after the optical fiber cladding light stripper and the waste light receiving device are assembled; Figure 4 It is an exploded view of the optical fiber cladding light stripper and the waste light receiving device after being assembled; Figure 5 An axonometric view of the heat-conducting base provided by the present invention; Figure 6 An axonometric view of the upper cover shell provided by the present invention (turned over with the bottom facing upward); Figure 7 Schematic diagram of the working principle of the fin group.

[0020] Figure markings: 1-heat-conducting base, 11-photothermal conversion groove one, 12-photothermal conversion fin group one, 13-fixing groove one, 14-heat-conducting card slot, 2-upper cover shell, 21-photothermal conversion groove two, 22-photothermal conversion fin group two, 23-fixing groove two, 24-heat-conducting fin, 25-through hole, 26-external photothermal conversion fin group, 3-optical fiber cladding light stripper, 31-double-clad optical fiber, 311-double-clad segment, 312-stripping segment, 32-glass tube, 4-notch. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings: like Figures 1 to 4 The shown embodiment is a waste light receiving device for an optical fiber cladding light stripper, comprising a heat-conducting base 1 and an upper cover shell 2. The upper cover shell 1 and the heat-conducting base 2 are fixedly connected and the interior is enclosed to form a photothermal conversion cavity. An internal photothermal conversion fin group is provided in the photothermal heat exchange cavity. The stripping section 311 of the double-clad optical fiber 31 of the optical fiber cladding light stripper 3 is placed in the photothermal conversion cavity. Both ends of the glass tube 32 of the optical fiber cladding light stripper 3 are installed and positioned through the heat-conducting base 1 and the upper cover shell 2.

[0023] Figure 2The basic structure diagram of the fiber cladding light stripper 3 currently widely used in high-power fiber lasers is shown. The fiber cladding light stripper 3 includes a double-clad optical fiber 31 and a packaging glass tube 32. The double-clad optical fiber 31 includes a double-clad segment 311 and a stripping segment 312. The stripping segment 312 is arranged between two double-clad segments 311. The common manufacturing method of the fiber cladding light stripper 3 is to remove the coating and outer cladding of a section of double-clad optical fiber 31, and then corrode the inner cladding with hydrofluoric acid or frosting paste, or mechanically polish the inner cladding to roughen and thin the inner cladding of the optical fiber to guide out the waste light therein. The optical fiber treated as above will lose the coating layer and even a certain thickness of the inner cladding, making this section of optical fiber more fragile. In order to protect this section of optical fiber, this section of optical fiber is usually encapsulated in a glass tube by high-temperature resistant glue or heating and melting.

[0024] In this embodiment, the top surface of the heat-conducting base 1 is provided with a light-to-heat conversion groove 11 along the length direction, and a light-to-heat conversion fin group 12 is vertically provided in the light-to-heat conversion groove 11. The top surface of the heat-conducting base 1 is symmetrically provided with a fixing groove 13 at both ends of the light-to-heat conversion groove 11, and the top surface of the heat-conducting base 1 is symmetrically provided with a heat-conducting card groove 14 parallel to the light-to-heat conversion groove 11. Figure 5 shown.

[0025] In this embodiment, a second photothermal conversion groove 21 is provided on the bottom surface of the upper cover shell 2 along the length direction, and a second photothermal conversion fin group 22 is vertically provided in the second photothermal conversion groove 21. A second fixing groove 23 is symmetrically provided on the bottom surface of the upper cover shell 2 at both ends of the second photothermal conversion groove 22, and a thermal conductive fin 24 adapted to the thermal conductive card slot 14 is symmetrically provided on the bottom surface of the upper cover shell 2 parallel to the second photothermal conversion groove 23.

[0026] In this embodiment, the bottom surface of the upper cover shell 2 is symmetrically provided with a through hole 25 for connecting the second fixing groove 23 and the outside of the upper cover shell 2. Figure 6 shown.

[0027] Specifically, after the upper cover shell 2 is covered downwardly on the heat-conducting base 1, the fixing groove 1 13 and the fixing groove 2 23 form a fixing channel for installing and fixing the optical fiber cladding light stripper 3, and the through hole 25 on the upper cover shell 2 is used to lay out the optical fibers at both ends of the cladding light stripper 3.

[0028] Furthermore, when installing the optical fiber cladding light stripper 3, an appropriate amount of high-temperature glue can be applied to the fixing groove 1 13 and the fixing groove 2 23, and the two ends of the glass tube 32 can be fixed in the fixing channel formed by the fixing groove 1 13 and the fixing groove 2 23 by the high-temperature glue to prevent the optical fiber cladding light stripper 3 from being damaged due to vibration.

[0029] It should be emphasized that what is fixed inside the fixed groove 13 and the fixed groove 23 is the double-clad segment 311 of the double-clad optical fiber 31, and the entire stripping segment 312 is located in the photothermal conversion cavity formed by the photothermal conversion groove 11 and the photothermal conversion groove 2 21, and there is a certain distance between the two ends of the stripping segment 312 and the end positions of the fixed channels at both ends.

[0030] In this embodiment, the photothermal conversion fin group 1 12 and the photothermal conversion fin group 2 22 have the same structure and are arranged opposite to each other, and together constitute the inner photothermal conversion fin group.

[0031] In this embodiment, the photothermal conversion fin group 1 12 and the photothermal conversion fin group 2 22 are both composed of a plurality of parallel fin blocks, and the distance between two adjacent fin blocks and the height of the fin blocks gradually decrease along the laser transmission direction.

[0032] In this embodiment, notches 4 of the same size are provided on the lower and upper end surfaces of the fin monoliths arranged opposite to each other, and the length of the notches 4 gradually decreases along the laser transmission direction, and the depth gradually increases along the laser transmission direction.

[0033] Specifically, Figure 7 As shown, the fin group structure in the photothermal conversion cavity can make the stripped cladding waste light produce multiple refractions between the fins, and compensate for the low absorption efficiency of 0.9~1.1μm lasers of commonly used materials such as aluminum, copper, and iron by increasing the contact area between the waste light and the cavity, and limit the photothermal conversion process as much as possible between the fins, effectively reducing the number of times the waste light passes through the double-clad optical fiber again, that is, reducing the reheating of the double-clad optical fiber by the waste light, while improving the photothermal conversion efficiency, it can significantly reduce the risk of burning the double-clad optical fiber, especially the stripping section 312. In addition, the optical fiber cladding light strippers made by various methods currently generally have a certain degree of uneven stripping problem, that is, the light energy stripped from the front end of the stripper is often greater than that from the rear end. The shape change and arrangement of the fins in the two fin groups can guide the waste light derived from the front end of the stripper to the middle and even rear fins of the photothermal conversion cavity for absorption, so that the photothermal conversion process is carried out evenly in the entire photothermal conversion cavity, avoiding the burning of the optical fiber due to local overheating, and reducing the pressure of the cooling system.

[0034] It should be emphasized that the shape of the notch 4 of the fin block in the photothermal conversion fin group 1 12 and the photothermal conversion fin group 2 22 includes but is not limited to a rectangle, and the change rule of the shape of the fin block will also be optimized with the shape of the notch 4, as long as the waste light guided out from the front end of the stripper can be guided to the middle and rear sections of the photothermal conversion cavity for absorption, it can be ensured that the photothermal conversion process is carried out evenly in the cavity.

[0035] In this embodiment, the upper cover shell 2 is provided with an external light-heat conversion fin group 26. The external light-heat conversion fin group 26 is composed of a plurality of fins of the same structure and evenly arranged in parallel, and is used to increase the contact area between the upper cover shell 2 and the air, thereby improving the heat dissipation efficiency.

[0036] In this embodiment, the heat-conducting base 1 and the upper cover shell 2 are both made of metal heat-conducting materials. Metal materials include but are not limited to aluminum, copper, iron, etc. The materials of the heat-conducting base 1 and the upper cover shell 2 can be the same or different.

[0037] In this embodiment, the heat-conducting base 1 and / or the upper cover shell 2 are provided with a heat dissipation channel, and the heat dissipation channel adopts a water cooling or air cooling channel. At the same time, the heat can also be conducted to other positions of the laser through a heat pipe for unified discharge.

[0038] In this embodiment, the heat conductive base 1 is integrated on the water cooling plate of the fiber laser and shares a cooling system with the fiber laser, which improves the heat dissipation efficiency while reducing the number of external water cooling pipes, reduces the risk of coolant leakage, and most importantly, can reduce the size and weight of the laser.

[0039] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A waste light receiving device for an optical fiber cladding light stripper, characterized in that: It includes a heat-conducting base and an upper cover shell, the upper cover shell and the heat-conducting base are fixedly connected and the interior is enclosed to form a photothermal conversion cavity, an internal photothermal conversion fin group is arranged in the photothermal heat exchange cavity, the stripping section of the double-clad optical fiber of the optical fiber cladding light stripper is placed in the photothermal conversion cavity, and the two ends of the glass tube of the optical fiber cladding light stripper are installed and positioned through the heat-conducting base and the upper cover shell.

2. The waste light receiving device of an optical fiber cladding light stripper according to claim 1, characterized in that: A light-to-heat conversion groove is provided on the top surface of the heat-conducting base along the length direction, a light-to-heat conversion fin group is vertically provided in the light-to-heat conversion groove, a fixing groove is symmetrically provided on the top surface of the heat-conducting base at both ends of the light-to-heat conversion groove, and a heat-conducting card groove is symmetrically provided on the top surface of the heat-conducting base parallel to the light-to-heat conversion groove.

3. The waste light receiving device of an optical fiber cladding light stripper according to claim 2, characterized in that: The bottom surface of the upper cover shell is provided with two photothermal conversion grooves along the length direction, and two photothermal conversion fin groups are vertically arranged in the two photothermal conversion grooves. Two fixing grooves are symmetrically arranged at both ends of the two photothermal conversion grooves on the bottom surface of the upper cover shell, and thermal conductive fins adapted to the thermal conductive card slots are symmetrically arranged on the bottom surface of the upper cover shell parallel to the two photothermal conversion grooves.

4. The waste light receiving device of an optical fiber cladding light stripper according to claim 3, characterized in that: The photothermal conversion fin group 1 and the photothermal conversion fin group 2 have the same structure and are arranged opposite to each other, and together constitute the inner photothermal conversion fin group.

5. The waste light receiving device of an optical fiber cladding light stripper according to claim 4, characterized in that: The photothermal conversion fin group 1 and the photothermal conversion fin group 2 are both composed of a plurality of fin blocks arranged in parallel, and the distance between two adjacent fin blocks and the height of the fin blocks gradually decrease along the laser transmission direction.

6. The waste light receiving device of an optical fiber cladding light stripper according to claim 5, characterized in that: The lower end surface and the upper end surface of the fin single block arranged opposite to each other are provided with notches of the same size, and the length of the notch gradually decreases along the laser transmission direction, and the depth gradually increases along the laser transmission direction.

7. The waste light receiving device of an optical fiber cladding light stripper according to claim 3, characterized in that: The bottom surface of the upper cover shell is also symmetrically provided with through holes for connecting the second fixing groove and the outside of the upper cover shell.

8. The waste light receiving device for an optical fiber cladding light stripper according to any one of claims 1 to 7, characterized in that: An external light-heat conversion fin group is arranged outside the upper cover shell.

9. The waste light receiving device of an optical fiber cladding light stripper according to claim 1, characterized in that: The heat-conducting base and / or the upper cover shell are provided with a heat dissipation channel inside, and the heat dissipation channel adopts a water cooling channel or an air cooling channel.

10. The waste light receiving device of an optical fiber cladding light stripper according to claim 1, characterized in that: The heat-conducting base is integrated on the water cooling plate of the optical fiber laser and shares a cooling system with the optical fiber laser.

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