A high-efficiency waveguide double-tapered single-crystal optical fiber gain module and its installation method

Abstract

A high-efficiency waveguide double-tapered single-crystal optical fiber gain module and an installation method thereof, comprising a double-tapered single-crystal optical fiber and a heat sink assembly; the heat sink assembly comprises a heat sink base and a heat sink cover plate; the heat sink base is provided with a cavity opening upward, a cooling liquid is provided in the cavity, the cavity is closed by the heat sink cover plate, and a sealing assembly is provided therebetween; the heat sink base is provided with through holes running through left and right, the through holes being connected to the cavity; the double-tapered single-crystal optical fiber comprises a single-crystal main body with cones on both sides and connected with the middle cone point, and a metal film layer plated on the outer side of the single-crystal main body, and the double-tapered single-crystal optical fiber passes through the through holes on both sides of the heat sink base; the high-efficiency waveguide double-tapered single-crystal optical fiber gain module and the installation method thereof not only realize high-efficiency heat dissipation of the double-tapered single-crystal optical fiber for generating high-power laser, but also extend the effective length of the double-tapered single-crystal optical fiber through the cladding layer, thereby improving the laser gain.

Description

Technical Field

[0001] The invention relates to the field of lasers, and in particular to a high-efficiency waveguide double-tapered single-crystal optical fiber gain module and an installation method thereof. Background Art

[0002] Single crystal fiber is an optical fiber made of single crystal material and is a new type of functional material. Compared with bulk crystal, single crystal fiber has the advantages of high aspect ratio, high optical waveguide conversion efficiency, large gain, etc. Compared with traditional optical fiber, single crystal fiber has the advantages of high thermal conductivity, good infrared transmittance, high damage threshold, low nonlinear effect, etc. These advantages make single crystal fiber have great application prospects in the field of high-power laser, especially in the field of mid-infrared high-power laser.

[0003] However, single crystal optical fiber also faces some problems in the application of high-power laser field. First of all, during the use of single crystal optical fiber, if there is no cladding, the bare fiber is easily affected by pollutants in the air and then the loss is too large. In addition, the refractive index of the bare fiber is quite different from that of the air, and the refractive index distribution of the air is uneven and difficult to control. If cladding, the cladding of the single crystal optical fiber must at least meet the following conditions: the refractive index of the cladding material must be lower than the refractive index, the thermal expansion coefficient must be close to, it must have good mechanical and thermochemical stability, and the cladding and interface must be in phase equilibrium and have a stable chemical structure. In addition, the preparation process has high requirements on the reaction conditions, the preparation process is complicated, and it is difficult to control the refractive index of the cladding. Patent CN110217981A proposes a method for preparing single crystal optical fiber and cladding, but its operation is relatively complicated and has high requirements on equipment. Secondly, due to quantum loss, single crystal optical fiber will generate a lot of heat energy when used in high-power lasers, and the heat dissipation problem is also a problem that needs to be solved urgently. Patent CN 204290021U proposes to use single crystal optical fiber made of Nd:YAG or YAP to replace traditional active optical fiber to improve the thermal conductivity of the laser gain medium and achieve high laser power. However, this solution does not involve the problem of optical fiber cladding, nor does it propose a specific active heat dissipation method. Summary of the invention

[0004] The present invention aims to provide a high-efficiency waveguide double-tapered single-crystal fiber gain module and an installation method thereof, which not only realizes efficient heat dissipation of the double-tapered single-crystal fiber through the double-tapered structure of the single-crystal fiber and is used for the generation of high-power laser, but also extends the effective length of the double-tapered single-crystal fiber through the cladding, improves the laser gain, and simplifies the experimental equipment and the preparation process.

[0005] To achieve the above object, the present invention provides a highly efficient waveguide double-tapered single crystal fiber gain module, comprising a double-tapered single crystal fiber and a heat sink assembly;

[0006] The heat sink assembly comprises a heat sink base and a heat sink cover plate; the heat sink base is provided with a cavity opening upward, a coolant is provided in the cavity, the cavity is closed by the heat sink cover plate, and a sealing assembly is provided therebetween;

[0007] The heat sink base is provided with through holes extending left and right, and the through holes are connected with the cavity;

[0008] The double-tapered single crystal optical fiber comprises a single crystal body with cone structures on both sides and connected by a cone point in the middle, and a metal film layer plated on the outer side of the single crystal body. The double-tapered single crystal optical fiber passes through the through holes on both sides of the heat sink base.

[0009] Furthermore, the metal film layer is a gold film or a silver film with a thickness of 10-50 nm.

[0010] Furthermore, the material of the single crystal main body is rare earth activated ion doped yttrium aluminum garnet crystal, sesquioxide crystal, or transition metal ion doped YAG crystal, sapphire, ZnSe crystal.

[0011] Furthermore, the rear end of the heat sink base is provided with a liquid outlet connected to the cavity, and the front end is provided with a liquid inlet connected to the cavity, and the liquid outlet and the liquid inlet are both provided with internal threads, and are correspondingly threadedly connected to the liquid outlet joint and the liquid inlet joint;

[0012] The liquid inlet connector is connected to the cooling device and the liquid outlet connector in sequence through a pipeline to form a loop. The liquid inlet is placed at the pump light input end, and the liquid outlet is placed at the laser output end.

[0013] Furthermore, the heat sink base is provided with mounting holes around its periphery, and the mounting holes are arranged with the peripheral opening of the heat sink base.

[0014] Furthermore, the length of the bi-tapered single crystal optical fiber is greater than 30 mm and the diameter is less than 1 mm. Both ends are respectively coated with anti-reflection films for laser and pump light. The diameter of the through hole is 20-50 microns larger than the diameter of the bi-tapered single crystal optical fiber. Both ends of the bi-tapered single crystal optical fiber are located outside the heat sink base, and the total length of the bi-tapered single crystal optical fiber is equal to the length of the heat sink.

[0015] Furthermore, the sealing assembly includes a sealing ring, an annular groove is provided at the upper end of the heat sink base and the outer side of the cavity, and the sealing ring is located in the annular groove;

[0016] The heat sink cover is provided with a plurality of fixing holes, and the upper end of the heat sink base is provided with a plurality of fastening threaded holes corresponding to the fixing holes. The locking screws pass through the fixing holes and are threadedly connected with the fastening threaded holes, so that the heat sink cover squeezes the sealing ring to seal.

[0017] Furthermore, the heat sink base and the heat sink cover are made of aluminum alloy or copper alloy.

[0018] A method for installing a high-efficiency waveguide double-tapered single-crystal optical fiber gain module specifically comprises the following steps:

[0019] a. Take a Tm:YAG double-tapered single crystal optical fiber with a diameter of 1 mm and a length of 50 mm, polish it, ultrasonically clean it, and dry it;

[0020] b. Use GVC-1000 ion sputtering instrument to coat the double-tapered single crystal optical fiber, and set the parameters, including working voltage, frequency, sputtering voltage, maximum power, sputtering current, sputtering time, working vacuum and vacuum rate;

[0021] c. The coating thickness is 1-50nm, and the coating of the double-tapered single crystal optical fiber is completed;

[0022] d. Place the coated double-tapered single-crystal optical fiber into the through holes that penetrate the left and right sides of the heat sink base, so that its middle is located in the cavity connected to the through hole, and seal the gap between the through hole and the double-tapered single-crystal optical fiber with UV-curable glue;

[0023] f. Place the O-ring in the annular groove at the upper end of the heat sink base, place the heat sink cover on the upper surface of the heat sink base, fasten the heat sink cover by locking screws, and apply pressure to the sealing ring to seal;

[0024] g. Connect the liquid inlet connector with the pipeline to the liquid inlet, and the liquid outlet connector to the liquid outlet. The coolant enters the cavity from the liquid inlet, and then flows out from the liquid outlet to the cooling device for cooling. The cooled coolant then enters the cavity to form a loop. The liquid inlet is placed at the pump light input end, and the liquid outlet is placed at the laser output end, completing the installation of the double-tapered single crystal optical fiber.

[0025] Furthermore, the parameters in step b are specifically as follows: working voltage is 200-240VAC, frequency is 50Hz, sputtering voltage is DC2400V, maximum power is 500W, sputtering current is less than 30mA, sputtering time is less than 600s, working vacuum is less than 30Pa, and vacuum rate is less than 2L / s.

[0026] Compared with the prior art, the present invention is a high-efficiency waveguide double-tapered single-crystal fiber gain module. Since the double-tapered single-crystal fiber includes a single-crystal body with cone structures on both sides and connected by cone points in the middle, and a metal film layer plated on the outer side of the single-crystal body, its cone structure can increase the number of total reflections, and the cone points are connected to each other in the middle to form a thinner node, which is helpful for mode limiting and improves the laser efficiency and beam quality; the outer side of the double-tapered single-crystal fiber is coated, and its reflectivity is higher by gold or silver metal plating, which prolongs the effective length of the double-tapered single-crystal fiber, improves the laser gain, reduces the dependence of the pump light on mode matching, and thus has the advantages of high efficiency and low power consumption. The laser gain is effectively improved, and the preparation method of the double-tapered single-crystal optical fiber is simple, which can simplify the experimental device and facilitate the operation, thereby avoiding the problem that the traditional double-tapered single-crystal optical fiber cladding preparation has high requirements on the experimental equipment and complicated preparation process; since the double-tapered single-crystal optical fiber passes through the through hole connected to the cavity, and a coolant is arranged in the cavity, the double-tapered single-crystal optical fiber with high thermal conductivity is cooled by the coolant, which can be used for the generation of high-power lasers. In addition, the coolant enters the cavity from the liquid inlet, and then flows out from the liquid outlet to the cooling device and the cavity to form a loop, so the cooling is more efficient through the recycling of the coolant. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an overall exploded view of the present invention;

[0028] Figure 2 is a schematic diagram of a double-tapered single crystal optical fiber of the present invention;

[0029] In the figure: 1. double-tapered single crystal optical fiber, 2. heat sink base, 3. heat sink cover, 4. sealing ring, 5. through hole, 6. liquid inlet, 7. liquid outlet, 8. fastening threaded hole, 9. fixing hole, 10. mounting hole, 11. annular groove, 12. cavity, 13. single crystal body, 14. metal film layer. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] like Figure 1 , Figure 2 As shown, the present invention is a highly efficient waveguide double-tapered single crystal fiber gain module comprising a double-tapered single crystal fiber 1 and a heat sink assembly;

[0032] The heat sink assembly includes a heat sink base 2 and a heat sink cover plate 3; the heat sink base 2 is provided with a cavity 12 opening upward, a coolant is provided in the cavity 12, the cavity 12 is closed by the heat sink cover plate 3, and a sealing assembly is provided therebetween;

[0033] The heat sink base 2 is provided with a through hole 5 which passes through the left and right sides, and the through hole 5 is connected with the cavity 12;

[0034] The double-tapered single crystal optical fiber 1 includes a single crystal body 13 with cone structures on both sides and connected by a cone point in the middle, and a metal film layer 14 plated on the outer side of the single crystal body 13 . The double-tapered single crystal optical fiber 1 passes through the through holes 5 on both sides of the heat sink base 2 .

[0035] The double-tapered single crystal optical fiber 1 is formed by the single crystal body 13 with tapered structures on both sides connected to each other. The tapered structure increases the number of total reflections, and the tapered points are connected to each other in the middle to form a thinner node, which is helpful for mode limiting and improves laser efficiency and beam quality.

[0036] Furthermore, the metal film layer 14 is a gold film or a silver film with a thickness of 10-50 nm;

[0037] Furthermore, the heat sink base 2 has a liquid outlet 7 at the rear end thereof connected to the cavity 12, and a liquid inlet 6 at the front end thereof connected to the cavity 12. The liquid outlet 7 and the liquid inlet 6 are both provided with internal threads, and are correspondingly threadedly connected to the liquid outlet joint and the liquid inlet joint;

[0038] The liquid inlet connector is connected to the cooling device and the liquid outlet connector in sequence through a pipeline to form a loop, the liquid inlet 6 is placed at the pump light input end, and the liquid outlet 7 is placed at the laser output end. The cooling device can be placed in a cooling liquid tank, and the cooling liquid tank is connected to the liquid outlet connector;

[0039] Furthermore, the height of the liquid inlet 6 is lower than the height of the liquid outlet 7;

[0040] Furthermore, the heat sink base 2 is provided with mounting holes 10 around its periphery, and the mounting holes 10 are open to the periphery of the heat sink base 2;

[0041] Further, the material of the single crystal body 13 is rare earth activated ion doped yttrium aluminum garnet crystal, sesquioxide crystal, or transition metal ion doped YAG crystal, sapphire, ZnSe crystal;

[0042] The rare earth activating ions are one or more of Nd3+, Yb3+, Tm3+, Ho3+, the yttrium aluminum garnet crystals are mainly YAG, the sesquioxide crystals are Y2O3, Sc2O3, Lu2O3, and the transition metal ions are one or more of Ti3+, Cr2+, Cr4+;

[0043] Further, the length of the single crystal body is greater than 30 mm, the diameter is less than 1 mm, the diameter of the through hole 5 is 20-50 microns larger than the diameter of the double-tapered single crystal optical fiber 1, the two ends of the double-tapered single crystal optical fiber 1 are located outside the heat sink base 2, and are respectively coated with anti-reflection films for laser and pump light, and the total length of the double-tapered single crystal optical fiber 1 is equal to the length of the heat sink;

[0044] Furthermore, the heat sink base 2 and the heat sink cover 3 are made of aluminum alloy or copper alloy;

[0045] Furthermore, the sealing assembly includes a sealing ring 4, and an annular groove 11 is provided at the upper end of the heat sink base 2 and the outer side of the cavity 12, and the sealing ring 4 is located in the annular groove 11;

[0046] The heat sink cover plate 3 is provided with a plurality of fixing holes 9, and the upper end of the heat sink base 2 is provided with a plurality of fastening threaded holes 8 corresponding to the fixing holes 9. The locking screws pass through the fixing holes 9 and are threadedly connected with the fastening threaded holes 8, so that the heat sink cover plate 3 squeezes the sealing ring 4 to seal the cavity 12;

[0047] The present invention discloses a method for installing a high-efficiency waveguide double-tapered single-crystal optical fiber gain module, which specifically includes making a double-tapered single-crystal optical fiber 1 and installing the double-tapered single-crystal optical fiber 1, wherein making the double-tapered single-crystal optical fiber 1 specifically includes the following steps:

[0048] a. Take a Tm:YAG double-tapered single crystal optical fiber 1 with a diameter of 1 mm and a length of 50 mm, polish it, ultrasonically freshen it, and dry it;

[0049] b. Use GVC-1000 ion sputtering instrument to coat the double-tapered single crystal optical fiber 1, and set its working voltage, frequency, sputtering voltage, maximum power, sputtering current, sputtering time, working vacuum and vacuum rate;

[0050] c. The coating thickness is 1-50 nm, and the coating of the double-tapered single crystal optical fiber 1 is completed;

[0051] The parameters in step b specifically include a working voltage of 200-240VAC, a frequency of 50Hz, a sputtering voltage of DC2400V, a maximum power of 500W, a sputtering current of less than 30mA, a sputtering time of less than 600s, a working vacuum of less than 30Pa, and a vacuum rate of less than 2L / s;

[0052] Installing the double-tapered single crystal optical fiber 1 specifically includes the following steps:

[0053] d. Place the coated double-tapered single-crystal optical fiber 1 into the through hole 5 passing through the left and right sides of the heat sink base 2, so that its middle part is located in the cavity 12 connected to the through hole 5, and seal the gap between the through hole 5 and the double-tapered single-crystal optical fiber 1 with a UV-curable adhesive;

[0054] f. Place the O-ring 4 in the annular groove 11 at the upper end of the heat sink base 2, place the heat sink cover 3 on the upper surface of the heat sink base 2, fasten the heat sink cover 3 by locking screws, and apply pressure to the sealing ring 4 to seal;

[0055] g. Connect the liquid inlet connector with the pipeline to the liquid inlet 6, and the liquid outlet connector to the liquid outlet 7. The coolant enters the cavity 12 from the liquid inlet 6, and then flows out from the liquid outlet 7 to the cooling device for cooling. The cooled coolant then enters the cavity 12 to form a loop. The liquid inlet 6 is placed at the pump light input end, and the liquid outlet 7 is placed at the laser output end, completing the installation of the double-tapered single crystal optical fiber 1. In addition, preferably, the coolant can be cooling water.

Claims

1. A highly efficient waveguided double-tapered single crystal fiber gain module, characterized in that: It comprises a double-tapered single crystal optical fiber (1) and a heat sink assembly; The heat sink assembly comprises a heat sink base (2) and a heat sink cover plate (3); the heat sink base (2) is provided with a cavity (12) opening upward, a cooling liquid is provided in the cavity (12), the cavity (12) is closed by the heat sink cover plate (3), and a sealing assembly is provided therebetween; The heat sink base (2) is provided with a through hole (5) penetrating left and right, and the through hole (5) is communicated with the cavity (12); The double-tapered single crystal optical fiber (1) comprises a single crystal body (13) with two sides having a conical structure and a middle cone point connected, and a metal film layer (14) plated on the outside of the single crystal body (13); the double-tapered single crystal optical fiber (1) passes through through holes (5) on both sides of the heat sink base (2); The metal film layer (14) is a gold film or a silver film with a thickness of 10-50 nm; The length of the bi-tapered single crystal optical fiber (1) is greater than 30 mm and the diameter is less than 1 mm. Both ends are respectively coated with anti-reflection films for laser and pump light. The diameter of the through hole (5) is 20-50 microns larger than the diameter of the bi-tapered single crystal optical fiber (1). Both ends of the bi-tapered single crystal optical fiber (1) are located outside the heat sink base (2). The total length of the bi-tapered single crystal optical fiber (1) is equal to the length of the heat sink.

2. A highly efficient waveguided double-tapered single crystal fiber gain module according to claim 1, characterized in that: The material of the single crystal main body (13) is rare earth activated ion doped yttrium aluminum garnet crystal, sesquioxide crystal, or transition metal ion doped YAG crystal, sapphire, ZnSe crystal.

3. A high-efficiency waveguided double-tapered single crystal fiber gain module according to claim 1 or 2, characterized in that: The heat sink base (2) has a liquid outlet (7) at the rear end thereof and a liquid inlet (6) at the front end thereof, wherein the liquid outlet (7) and the liquid inlet (6) are both provided with internal threads and are correspondingly threadedly connected to the liquid outlet joint and the liquid inlet joint; The liquid inlet connector is connected to the cooling device and the liquid outlet connector in sequence through a pipeline to form a loop; the liquid inlet (6) is disposed at the pump light input end, and the liquid outlet (7) is disposed at the laser output end.

4. A high-efficiency waveguided double-tapered single crystal fiber gain module according to claim 3, characterized in that: The heat sink base (2) is provided with mounting holes (10) on the periphery thereof, and the mounting holes (10) are arranged with the peripheral opening of the heat sink base (2).

5. The high-efficiency waveguide double-tapered single crystal fiber gain module according to claim 3, characterized in that: The sealing assembly comprises a sealing ring (4), an annular groove (11) is provided at the upper end of the heat sink base (2) and on the outer side of the cavity (12), and the sealing ring (4) is located in the annular groove (11); The heat sink cover plate (3) is provided with a plurality of fixing holes (9), and the upper end of the heat sink base (2) is provided with a plurality of fastening threaded holes (8) corresponding to the fixing holes (9). Locking screws pass through the fixing holes (9) and are threadedly connected to the fastening threaded holes (8), so that the heat sink cover plate (3) squeezes the sealing ring (4) to seal.

6. A high-efficiency waveguided double-tapered single crystal fiber gain module according to claim 5, characterized in that: The heat sink base (2) and the heat sink cover plate (3) are made of aluminum alloy or copper alloy.

7. A method for installing a high-efficiency waveguide double-tapered single crystal fiber gain module, characterized in that: The specific steps include: a. Take a 1mm diameter, 50mm length Tm: YAG double-tapered single crystal optical fiber (1), polish it, ultrasonic fresh, and dry it; b. Coating the double-tapered single crystal optical fiber (1) using a GVC-1000 ion sputtering apparatus, setting parameters including operating voltage, frequency, sputtering voltage, maximum power, sputtering current, sputtering time, operating vacuum and vacuum rate; c. The coating thickness is 1-50 nm, and the coating of the double-tapered single crystal optical fiber (1) is completed; d. Place the coated bi-conical single crystal optical fiber (1) into the through hole (5) passing through the left and right sides of the heat sink base (2), so that its middle part is located in the cavity (12) connected to the through hole (5), and seal the gap between the through hole (5) and the bi-conical single crystal optical fiber (1) with a UV curable adhesive; f. Place the O-ring (4) in the annular groove (11) at the upper end of the heat sink base (2), place the heat sink cover (3) on the upper surface of the heat sink base (2), fasten the heat sink cover (3) by locking screws, and apply pressure to the sealing ring (4) to seal; g. Connect the liquid inlet connector with the pipeline to the liquid inlet (6), and connect the liquid outlet connector to the liquid outlet (7). The coolant enters the cavity (12) from the liquid inlet (6), and then flows out from the liquid outlet (7) to the cooling device for cooling. The cooled coolant then enters the cavity (12) to form a loop. The liquid inlet (6) is placed at the pump light input end, and the liquid outlet (7) is placed at the laser output end, thereby completing the installation of the double-tapered single crystal optical fiber (1).

8. The method for installing a high-efficiency waveguide double-tapered single crystal fiber gain module according to claim 7, characterized in that: The specific parameters in step b are: working voltage is 200-240VAC, frequency is 50Hz, sputtering voltage is DC2400V, maximum power is 500W, sputtering current is less than 30mA, sputtering time is less than 600s, working vacuum is less than 30Pa, and vacuum rate is less than 2L / s.

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