Double-coupled coherent array fiber laser, fiber signal combiner manufacturing device and method

Abstract

The present invention discloses a dual-coupled coherent array fiber laser, comprising: a high reflectivity layer, a first passive medium layer, a first fiber signal combiner, an active fiber, a second fiber signal combiner, a second passive medium layer and a low reflectivity layer arranged in sequence along the optical path direction, which constitute a resonant cavity; a plurality of fiber pump combiners are placed in the resonant cavity, so that the pump light generated by the pump light source is coupled into the resonant cavity through the fiber pump combiner, and the active fiber is used to absorb the pump light to achieve a particle number inversion and generate laser. The present invention adopts a dual fiber signal combiner, which can evenly distribute the power of multiple input light beams to the output fiber, realize power balance between the light beams, and help improve the stability and performance of the entire laser system, and the dual fiber signal combiner can mix light beams of different modes together, and at the same time, the dual fiber signal combiner can reduce the connection loss between optical fibers, improve the transmission efficiency of the light beam, and reduce energy loss.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber lasers, and in particular to a manufacturing device and method for a double-coupled coherent array optical fiber laser and an optical fiber signal combiner. Background Art

[0002] In recent years, fiber lasers have attracted much attention due to their advantages such as good beam quality, high electro-optical efficiency, good heat dissipation characteristics, compact structure, and good reliability, and have been widely used in many fields, such as fiber-optic communications, laser processing, military defense, and laser medical treatment. With the increasing demand for efficiency in industrial applications, it has become an urgent need to obtain high-beam-quality and high-power fiber lasers. However, due to factors such as the thermal effect, nonlinear effect, pumping technology, and mode instability of the optical fiber itself, the output power of a single-channel fiber laser is limited.

[0003] In the existing technology, multi-path active phase-locked coherent synthesis technology can achieve higher power laser output on the basis of overcoming the output power limit of a single-path fiber laser. Active phase-locked coherent synthesis technology mostly uses heterodyne method, random parallel gradient descent method, frequency domain multi-jitter method and other technologies, which dramatically increases the number of devices in the entire system and the complexity of connections, making it difficult to adjust. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a manufacturing device and method for a dual-coupled coherent array fiber laser and a fiber signal combiner.

[0005] The present invention discloses a dual-coupled coherent array fiber laser, comprising: a high reflectivity layer, a first passive medium layer, a first fiber signal combiner, an active fiber, a second fiber signal combiner, a second passive medium layer and a low reflectivity layer sequentially arranged along the optical path direction;

[0006] The high reflectivity layer, the first passive medium layer, the first optical fiber signal combiner, multiple active optical fibers, the second optical fiber signal combiner, the second passive medium layer, and the low reflectivity layer constitute a resonant cavity. Multiple optical fiber pump combiners are placed in the resonant cavity. Each optical fiber pump combiner is connected to multiple pump light sources, so that the pump light generated by the pump light source is coupled into the resonant cavity through the optical fiber pump combiner. The active optical fiber is used to absorb the pump light to achieve particle number inversion and generate laser.

[0007] As a further improvement of the present invention, both the first optical fiber signal combiner and the second optical fiber signal combiner are manufactured by optical fiber fusion drawing.

[0008] As a further improvement of the present invention, there are multiple pump light sources which are symmetrically arranged, and the pumping mode of the pump light sources is single-end pumping, double-end pumping or distributed lateral pumping.

[0009] As a further improvement of the present invention, the high reflectivity layer and the low reflectivity layer are respectively arranged on the end faces of the first passive medium layer and the second passive medium layer, and the reflectivities provided by the high reflectivity layer and the low reflectivity layer meet the requirements of laser lasing conditions; the first passive medium layer and the second passive medium layer are light-transmitting medium sheets or air external cavities.

[0010] As a further improvement of the present invention, the active optical fiber is a closely arranged optical fiber array made of N expanded core optical fibers with a gradient refractive index, N is a natural number greater than or equal to 2, and the active optical fiber is a single-clad optical fiber, a double-clad optical fiber or a triple-clad optical fiber;

[0011] The second passive medium layer and the low reflectivity layer form an external cavity, which is arranged in parallel with the end face of the second optical fiber signal combiner, and provides an optical path of an integer or fractional multiple of the Talbot distance for the optical fiber array.

[0012] The present invention also discloses a manufacturing device for an optical fiber signal combiner, which is used to realize the preparation of a first optical fiber signal combiner and a second optical fiber signal combiner, and comprises: a tower frame, in which a feeder, a preheating furnace, a heating furnace, an annealing and cooling mechanism and a pulling mechanism are arranged in sequence from top to bottom;

[0013] The feeder clamps a preform rod at the bottom, and the feeder is used to drive the preform rod to move downward, and the preform rod that moves downward is preheated by the preheating furnace. The preheated preform rod is melted into wire by the heating furnace and annealed and cooled by the annealing and cooling mechanism, and then pulled by the traction mechanism with the integrated molten cone part.

[0014] As a further improvement of the present invention, a vacuum device is provided on the top of the feeder, and the preheating furnace and the heating furnace are both provided with air inlet holes and exhaust holes, which are connected to an inert gas source outside the tower.

[0015] As a further improvement of the present invention, it further comprises a detection component; the detection component is located between the annealing and cooling mechanism and the pulling mechanism.

[0016] The present invention also discloses a method for manufacturing an optical fiber signal combiner, which is used to prepare a first optical fiber signal combiner and a second optical fiber signal combiner, comprising:

[0017] Step 1: Take a plurality of optical fibers and insert them into a casing to make a preform;

[0018] Step 2: Place the preform into the drawing tower, and the top of the preform is fixed on the feeder;

[0019] Step 3: preheating in a preheating furnace, wherein the preheating time is 800-1000°C;

[0020] Step 4: After preheating, the feeder continues to move down and enters the heating furnace. After heating, it naturally flows out in the form of filaments. After annealing and cooling by the annealing and cooling mechanism, the fused cone is pulled by the pulling mechanism.

[0021] As a further improvement of the present invention,

[0022] In step 2, a vacuum device is provided at the top of the feeder to remove impurities in the preform;

[0023] In step 3 and step 4, the preheating furnace and the heating furnace are both provided with air inlet and exhaust holes. During the preheating and taper heating process, a certain amount of inert gas is introduced into the preheating furnace and the heating furnace to control the circulation of the gas and exhaust the residual air through the air outlet to prevent the optical fiber from being oxidized at high temperature;

[0024] In step 4, a real-time detection process is also included to detect the diameter of the conical tip of the fusion cone portion and the length of the cone.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention adopts a dual-fiber signal combiner to evenly distribute the power of multiple input light beams to the output optical fiber, achieve power balance between the light beams, and help improve the stability and performance of the entire laser system. The dual-fiber signal combiner can mix light beams of different modes together, which helps to improve the output beam quality and beam stability of the laser. At the same time, the dual-fiber signal combiner can reduce the connection loss between optical fibers, improve the transmission efficiency of the light beam, and reduce energy loss.

[0027] 2. The present invention uses a pump light source to pump the active optical fiber to generate array laser output, and changes the mode distribution of the array laser by adjusting the length of the passive medium layer structure to achieve efficient self-injection feedback; the present invention can achieve coherent laser output in the same phase mode, has a simple structure, and can achieve high-power and high-energy density laser output without the need for a complex active phase modulator.

[0028] 3. The present invention directly adopts the existing drawing tower to improve the manufacturing method, and can produce more specifications of optical fiber signal combiners. It is no longer limited by the diameter of the taper machine manufacturing method, and can produce more diverse optical fiber signal combiners. It has a clever design and is easy to produce and manufacture, which solves the barriers of the existing technology.

[0029] 4. The present invention preheats the preheating furnace at 800-1000°C for 5 minutes to make the internal and external temperatures of the preform rod consistent. The consistent internal and external temperatures of the preform rod can reduce the generation of thermal stress and avoid stress concentration caused by temperature differences during the manufacturing process, thereby reducing the risk of cracks or deformation during the manufacturing process of the optical fiber signal combiner. At the same time, it also helps to ensure the overall quality stability of the optical fiber signal combiner, reduce the impact of temperature changes during the manufacturing process on product performance, and improve product stability and reliability.

[0030] 5. During the preheating and taper heating process, the present invention introduces a certain amount of inert gas into the preheating furnace and the heating furnace, controls the circulation of the gas, and discharges the residual air through the outlet. This not only prevents the oxidation of the optical fiber under high temperature conditions and extends the service life of the optical fiber, but also makes the temperature distribution in the preheating and heating process more uniform, avoiding excessive temperature gradients caused by uneven gas and affecting product quality.

[0031] 6. The present invention arranges a vacuum device at the top of the feeder, which can not only remove bubbles in the feeder, ensure that the optical fibers inside the preform are arranged neatly, avoid the influence of bubbles on the quality and performance of the optical fibers, reduce the interference of gas in the manufacturing process of the optical fiber signal combiner, and improve the quality stability of the product, but also ensure that the internal environment of the feeder is clean and dust-free, avoid the influence of impurities or foreign matter on the quality of the optical fibers, and improve the quality and performance of the optical fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a double-coupled coherent array fiber laser disclosed in an embodiment of the present invention;

[0033] Figure 2 A schematic structural diagram of a manufacturing device for an optical fiber signal combiner disclosed in an embodiment of the present invention;

[0034] Figure 3 The present invention is a schematic diagram of the structure of a fiber optic signal combiner disclosed in an embodiment of the present invention.

[0035] In the figure:

[0036] 1. Tower; 2. Feeder; 3. Vacuuming device; 4. Preform rod; 5. Preheating furnace; 6. Heating furnace; 7. Inert gas source; 8. Detection component; 9. Pulling mechanism; 10. Annealing and cooling mechanism; 11. High reflectivity layer; 12. First passive medium layer 13. First optical fiber signal combiner; 14. Pump light source; 15. Optical fiber pump combiner; 16. Active optical fiber; 17. Second optical fiber signal combiner; 18. Second passive medium layer; 19. Low reflectivity layer. DETAILED DESCRIPTION

[0037] 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.

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0039] like Figure 1 As shown, the present invention provides a dual-coupled coherent array fiber laser, comprising a high reflectivity layer 11, a first passive medium layer 12, a first fiber signal combiner 13, an active fiber 16, a second fiber signal combiner 17, a second passive medium layer 18 and a low reflectivity layer 19 which are sequentially arranged along the optical path direction. The high reflectivity layer 11, the first passive medium layer 12, the first fiber signal combiner 13, a plurality of active fibers 16, the second fiber signal combiner 17, the second passive medium layer 18 and the low reflectivity layer 19 constitute a resonant cavity, a plurality of fiber pump combiners 15 are placed in the resonant cavity, and each fiber pump combiner 15 is connected to a plurality of pump light sources 14, so that the pump light generated by the pump light source 14 is coupled into the resonant cavity through the fiber pump combiner 15.

[0040] The high reflectivity layer 11 and the low reflectivity layer 19 are respectively arranged on the end faces of the first passive dielectric layer 12 and the second passive dielectric layer 18, and are made by a coating process, and the reflectivity provided meets the requirements of the laser lasing conditions. The first passive dielectric layer 12 and the second passive dielectric layer 18 are light-transmitting dielectric sheets or air external cavities. The second passive dielectric layer 18 and the low reflectivity layer 19 constitute an external cavity, which is arranged parallel to the end face of the second optical fiber signal combiner 17, and provides an optical path of an integer or fractional multiple of the Talbot distance for the optical fiber array. Through the above-mentioned external cavity structure, the output mode of the laser can be better controlled to achieve laser output in a specific mode. It can also improve the frequency stability of the laser, reduce frequency drift, and help maintain the stable output of the laser within a certain frequency range.

[0041] The first fiber signal combiner 13 and the second fiber signal combiner 17 are both manufactured by fiber fusion drawing. There are multiple pump light sources 14, and they can be arranged symmetrically. The pumping mode of the pump light source 14 is single-end pumping, double-end pumping or distributed lateral pumping. The active fiber 16 is a tightly arranged fiber array made of N gradient refractive index expanded core fibers, N is a natural number greater than or equal to 2, and the active fiber 16 can be any one of a single-clad fiber, a double-clad fiber or a triple-clad fiber. Preferably, the active fiber 16 is a triple-clad fiber.

[0042] The present invention adopts a dual-fiber signal combiner, which can evenly distribute the power of multiple input light beams to the output optical fiber, achieve power balance between the light beams, and help improve the stability and performance of the entire laser system. The dual-fiber signal combiner can mix light beams of different modes together, which helps to improve the output beam quality and beam stability of the laser. At the same time, the dual-fiber signal combiner can reduce the connection loss between optical fibers, improve the transmission efficiency of the light beam, and reduce energy loss.

[0043] The present invention uses a pump light source to pump an active optical fiber to generate array laser output, and changes the mode distribution of the array laser by regulating the length of the passive medium layer structure to achieve efficient self-injection feedback; the present invention can achieve coherent laser output in the same phase mode, has a simple structure, and achieves high-power and high-energy density laser output without the need for a complex active phase modulator.

[0044] like Figure 2 As shown, the present invention provides a manufacturing device for an optical fiber signal combiner, which is used to manufacture a first optical fiber signal combiner 13 and a second optical fiber signal combiner 17; the manufacturing device comprises: a tower 1, in which a feeder 2, a preheating furnace 5, a heating furnace 6, an annealing and cooling mechanism 10 and a pulling mechanism 9 are arranged from top to bottom; wherein the feeder 2 has a preform 4 clamped at the bottom, and the feeder 2 is used to drive the preform 4 to move downward, and the preform 4 moved downward passes through the preheating furnace 5, the heating furnace 6 and the annealing and cooling mechanism 10 in sequence; the pulling mechanism 9 pulls the bottom end of the optical fiber signal combiner formed after preheating, heating, annealing and cooling, and the structure of the manufactured optical fiber signal combiner is as shown in FIG. Figure 3 shown.

[0045] Furthermore, both the preheating furnace 5 and the heating furnace 6 are provided with air inlet holes and air outlet holes, which are connected to an inert gas source 7 outside the tower 1 . Both the preheating furnace 5 and the heating furnace 6 are graphite furnaces.

[0046] Furthermore, a vacuum device 3 is provided at the top of the feeder 2. The vacuum device 3 is provided at the top of the feeder. The present invention can not only remove bubbles in the feeder, ensure that the optical fibers inside the preform rod 4 are arranged neatly, avoid the influence of bubbles on the quality and performance of the optical fibers, reduce the interference of gas in the manufacturing process of the optical fiber signal combiner, and improve the quality stability of the product, but also ensure that the internal environment of the feeder is clean and dust-free, avoid the influence of impurities or foreign matter on the quality of the optical fibers, and improve the quality and performance of the optical fibers.

[0047] Furthermore, it also includes a detection component 8, which is located between the annealing and cooling mechanism 10 and the pulling mechanism 9. The detection component 8 can measure the diameter of the cone tip and the length of the cone in real time; the pulling mechanism 9 can also adjust the distance, and the pulling range is wider.

[0048] The present invention can produce optical fiber signal combiners of more specifications, and is no longer limited by the diameter of the taper machine manufacturing method. More diverse optical fiber signal combiners can be produced, the design is ingenious, the production and manufacturing are convenient, and the barriers of the prior art are solved.

[0049] like Figure 2 As shown, based on the above manufacturing device, the present invention provides a method for manufacturing an optical fiber signal combiner, comprising:

[0050] S1, take a plurality of optical fibers, insert them into a casing to make a preform rod 4, wherein the number of optical fibers is 20 to 5000;

[0051] S2, placing the preform 4 into the drawing tower, the top of the preform 4 is fixed on the feeder 2, and a vacuum device 3 is provided on the top of the feeder to remove impurities in the preform 4;

[0052] S3. Preheating is performed in a preheating furnace 5, wherein the preheating temperature is 800-1000°C, the preheating time is 1-10 minutes, preferably 5 minutes, so that the internal and external temperatures of the preform rod 4 are consistent; the present invention preheats the preheating furnace 5 at 800-1000°C for 5 minutes to make the internal and external temperatures of the preform rod 4 consistent. The consistent internal and external temperatures of the preform rod 4 can reduce the generation of thermal stress and avoid stress concentration caused by temperature differences during the manufacturing process, thereby reducing the risk of cracks or deformation during the manufacturing process of the optical fiber signal combiner. At the same time, it also helps to ensure the overall quality stability of the optical fiber signal combiner, reduce the impact of temperature changes during the manufacturing process on product performance, and improve the stability and reliability of the product.

[0053] S4. After preheating is completed, the feeder 2 continues to move downward and enters the heating furnace 6. After heating, it naturally flows out in the form of filaments. After annealing and cooling by the annealing and cooling mechanism 10, the fused cone part is pulled by the traction mechanism 9. Among them, in step S4, a real-time detection process is also included to detect the diameter of the conical tip of the fused cone part and the length of the cone.

[0054] Further, in steps S3 and S4, both the preheating furnace 5 and the heating furnace 6 are provided with air inlet holes and exhaust holes. During the preheating and taper heating process, a certain amount of inert gas is introduced into the preheating furnace 5 and the heating furnace 6, the circulation of the gas is controlled, and residual air is discharged through the air outlet to prevent the optical fiber from being oxidized under high temperature conditions. The present invention not only prevents the oxidation of the optical fiber under high temperature conditions and prolongs the service life of the optical fiber, but also makes the temperature distribution during the preheating and heating process more uniform, avoiding excessive temperature gradients caused by uneven gas and affecting product quality.

[0055] 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 dual-coupled coherent array fiber laser, characterized in that: include: A high reflectivity layer, a first passive medium layer, a first optical fiber signal combiner, an active optical fiber, a second optical fiber signal combiner, a second passive medium layer and a low reflectivity layer are sequentially arranged along the optical path direction; The high reflectivity layer, the first passive medium layer, the first fiber signal combiner, the multiple active fibers, the second fiber signal combiner, the second passive medium layer, and the low reflectivity layer constitute a resonant cavity. Multiple fiber pump combiners are placed in the resonant cavity. Each fiber pump combiner is connected to multiple pump light sources, so that the pump light generated by the pump light source is coupled into the resonant cavity through the fiber pump combiner. The active fiber is used to absorb the pump light to achieve population inversion and generate laser light. The high reflectivity layer and the low reflectivity layer are respectively arranged on the first passive medium layer, the second passive medium layer, and the second passive medium layer. The end faces of a passive dielectric layer and a second passive dielectric layer, the reflectivities provided by the high reflectivity layer and the low reflectivity layer meet the requirements of laser lasing conditions; the active optical fiber is a tightly arranged optical fiber array made of N expanded core optical fibers with gradient refractive index, N is a natural number greater than or equal to 2; the second passive dielectric layer and the low reflectivity layer constitute an external cavity, which is arranged in parallel with the end face of the second optical fiber signal combiner, providing an optical path of an integer or fractional multiple of the Talbot distance for the optical fiber array; the mode distribution of the array laser is changed by adjusting the length of the passive dielectric layer structure; The first optical fiber signal combiner and the second optical fiber signal combiner are both manufactured by optical fiber fusion drawing.

2. The dual-coupled coherent array fiber laser according to claim 1, characterized in that: There are multiple pump light sources which are symmetrically arranged, and the pump light sources are pumped in a single-end pumping, double-end pumping or distributed lateral pumping mode.

3. The dual-coupled coherent array fiber laser according to claim 1, characterized in that: The first passive medium layer and the second passive medium layer are light-transmitting medium sheets or air external cavities.

4. The dual-coupled coherent array fiber laser according to claim 1, characterized in that: The active optical fiber is a single-clad optical fiber, a double-clad optical fiber or a triple-clad optical fiber.

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