A tunable single-frequency pulsed fiber laser

Abstract

The present invention discloses a tunable single-frequency pulsed fiber laser, belonging to the technical field of fiber lasers, including a housing. Inside the housing, there are successively arranged a pump source assembly, a gain assembly, and a resonant cavity assembly from right to left. The pump source assembly includes multiple upper pump sources fixedly arranged on the top wall of the housing and multiple lower pump sources fixedly arranged on the bottom wall of the housing. The upper pump sources are arranged in two rows in an inclined and symmetric manner. For this tunable single-frequency pulsed fiber laser, the upper pump sources and the lower pump sources are simultaneously cooled through a heat dissipation plate. The second branch flow channel brings the coolant into the pump source to improve the heat dissipation effect. The inclined and symmetrically arranged pump sources reduce the fiber curvature and, in cooperation with the heat pipes arranged through, enable the heat pipes to dissipate heat from the heat dissipation plate and the pump source, further improving the heat dissipation effect. Compared with the existing devices, the problem of unsatisfactory heat dissipation effect when the pump sources are stacked is avoided, and the heat dissipation effect is optimized.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber lasers, and particularly relates to a tunable single-frequency pulsed fiber laser. Background Art

[0002] A fiber laser is a laser that uses a rare-earth element-doped glass optical fiber as a gain medium. It requires multiple pump sources to generate pump light, and under the action of the pump light, the laser energy levels of the laser working substance are "population inverted" to generate a coherent laser beam. The greater the output power of the fiber laser, the greater the power required for its pump source.

[0003] Most of the existing fiber lasers pursue greater power. A common laser needs to be provided with a pump source, a gain medium, and a resonant cavity inside, while a tunable single-frequency pulsed fiber laser needs to be provided with a tunable optical filter assembly, a Q-switching component, an optical coupler, etc. inside to achieve laser tuning and pulsed output. In this way, the space allocated to the heat dissipation components inside the tunable single-frequency pulsed fiber laser is relatively limited, and the heat dissipation effect of the circulating cooling water commonly used in the prior art is not ideal.

[0004] For the above problems, an improved solution is a fiber laser as shown in the authorized publication number CN117559201B, including: a cooling plate and a pump source, and a plurality of the pump sources form a pump source array and are arranged in a preset area of the cooling plate. The above solution directly passes circulating cooling water into the copper block at the bottom of the pump source to shorten the distance from the LD chip to the cooling water. However, this solution has an unsatisfactory heat dissipation effect when facing stacked pump sources.

[0005] Therefore, we propose a tunable single-frequency pulsed fiber laser to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to solve the problem of unsatisfactory heat dissipation effect in the prior art, and to propose a tunable single-frequency pulsed fiber laser.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A tunable single-frequency pulsed fiber laser, comprising a housing. Inside the housing, a pump source assembly, a gain assembly, and a resonant cavity assembly are successively arranged from right to left. The pump source assembly includes a plurality of upper pump sources fixedly arranged on the top wall of the housing and a plurality of lower pump sources fixedly arranged on the bottom wall of the housing. The upper pump sources are arranged in two inclined symmetrical columns, and the pigtail of the upper pump source faces the middle of the gain assembly. The number and arrangement of the lower pump sources are the same as those of the upper pump sources. A heat dissipation plate is arranged in the middle of the housing, and the top surface of the heat dissipation plate is simultaneously attached to all the upper pump sources, and the bottom surface is simultaneously attached to all the lower pump sources. A water pipe assembly and a plurality of heat pipes are arranged inside the heat dissipation plate, and both ends of the water pipe assembly extend to the outside of the housing;

[0009] The water pipe assembly includes a water inlet pipe, a water outlet pipe, a plurality of first branch channels, a plurality of second branch channels, and a plurality of third branch channels that cooperate with each other. The first branch channel and the second branch channel on the same side are connected by two second branch channels. The second branch channel located above extends to the lower end inside the upper pump source, and the branch channel located below extends to the upper end inside the lower pump source. The coolant flows through the water inlet pipe, the first branch channel, the second branch channel, the third branch channel, and the water outlet pipe in sequence.

[0010] The heat pipe is located between two second branch channels on the same side, and one end of the heat pipe far away from the gain assembly extends to the outside of the heat dissipation plate.

[0011] Preferably, the inclination angle of the upper pump source is between 30° and 60°.

[0012] Preferably, the upper pump sources are arranged in a 2×4 pattern, the lower pump sources correspond to the upper pump sources one by one, and the lower pump sources are located directly below the upper pump sources.

[0013] Preferably, the second branch channel includes a plate-shaped cavity inside the pump source assembly and a shunt pipe inside the heat dissipation plate. The two shunt pipes on the same side are connected to the cavity.

[0014] Preferably, the heat pipes are arranged in a 2×2 pattern, and the top surface of the heat pipe located above is attached to the bottom surface of the upper pump source, and the bottom surface of the heat pipe located below is attached to the top surface of the lower pump source.

[0015] Preferably, one ends of the plurality of heat pipes located outside the heat dissipation plate are commonly connected with a plurality of fins.

[0016] Preferably, a plurality of heat dissipation holes are formed at one end of the housing close to the fins.

[0017] In summary, the technical effects and advantages of the present invention are as follows: For the tunable single-frequency pulsed fiber laser, the upper pump source and the lower pump source are simultaneously cooled through the heat dissipation plate. The second branch flow channel brings the coolant into the pump source to improve the heat dissipation effect. The pump sources arranged symmetrically and obliquely reduce the fiber curvature and, in cooperation with the heat pipes arranged therethrough, enable the heat pipes to dissipate heat from the heat dissipation plate and the pump source, further improving the heat dissipation effect. Compared with the existing devices, the problem of unsatisfactory heat dissipation effect when the pump sources are stacked is avoided, and the heat dissipation effect is optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the present invention;

[0019] Figure 2 is a schematic cross-sectional structural diagram of the present invention;

[0020] Figure 3 is a schematic structural diagram of the present invention with the heat dissipation plate removed at the pump source assembly;

[0021] Figure 4 is Figure 3 a schematic cross-sectional structural diagram with the heat pipe removed in

[0022] Figure 5 is a schematic cross-sectional view of the heat dissipation plate at the second branch flow channel of the present invention.

[0023] In the figure: 1, housing; 2, gain assembly; 3, resonator assembly; 4, upper pump source; 5, lower pump source; 6, heat dissipation plate; 7, heat pipe; 8, water inlet pipe; 9, water outlet pipe; 10, first branch flow channel; 11, second branch flow channel; 12, third branch flow channel; 13, cavity; 14, shunt pipe; 15, fin; 16, heat dissipation hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0025] Refer to Figures 1-3, A tunable single-frequency pulsed fiber laser, comprising a housing 1. Inside the housing 1, a pump source assembly, a gain assembly 2, and a resonant cavity assembly 3 are sequentially arranged from right to left. The gain assembly 2 is a prior art and includes a gain fiber doped with rare earth ions (such as erbium-doped, ytterbium-doped, etc.). The resonant cavity assembly 3 is a prior art and includes a linear cavity and a ring cavity part. The linear cavity part is jointly composed of a high-reflectivity chirped fiber grating, a high-gain fiber, and a low-reflectivity chirped fiber grating, and is used to form a resonant circuit for the laser. The ring cavity part includes an optical circulator, a tunable optical filter assembly, a Q-switching component, an optical coupler, etc., and is used to achieve the tuning and pulsed output of the laser. The pump source assembly includes a plurality of upper pump sources 4 fixedly arranged on the top wall of the housing 1, and a plurality of lower pump sources 5 fixedly arranged on the bottom wall of the housing 1. The upper pump sources 4 are arranged in two columns in an inclined and symmetric manner, and the pigtail ends of the upper pump sources 4 face the middle of the gain assembly 2. The number and arrangement of the lower pump sources 5 are the same as those of the upper pump sources 4. A heat dissipation plate 6 is provided in the middle of the housing 1, and the top surface of the heat dissipation plate 6 is simultaneously attached to all the upper pump sources 4, and the bottom surface is simultaneously attached to all the lower pump sources 5. A water pipe assembly and a plurality of heat pipes 7 are provided inside the heat dissipation plate 6, and both ends of the water pipe assembly extend to the outside of the housing 1.

[0026] Referring to Figures 3-5 , the water pipe assembly includes a water inlet pipe 8, a water outlet pipe 9, a plurality of first branch channels 10, a plurality of second branch channels 11, and a plurality of third branch channels 12 that cooperate with each other. The first branch channel 10 and the third branch channel 12 on the same side are connected by two second branch channels 11. The second branch channel 11 located above extends to the lower end inside the upper pump source 4, and the branch channel located below extends to the upper end inside the lower pump source 5. The coolant flows through the water inlet pipe 8, the first branch channel 10, the second branch channel 11, the third branch channel 12, and the water outlet pipe 9 in sequence.

[0027] The heat pipe 7 is located between two second branch channels 11 on the same side, and one end of the heat pipe 7 away from the gain assembly 2 extends to the outside of the heat dissipation plate 6.

[0028] A water pump should be provided outside the water pipe assembly, and a coolant should be filled inside the water pipe assembly. The coolant is driven by the water pump to circulate for heat dissipation. The above is a prior art and will not be elaborated further.

[0029] For this tunable single-frequency pulsed fiber laser, when the load is not high and the heat generated by the pump source assembly is not large, the water pipe assembly can be not turned on, and only the heat pipes 7 are used for heat dissipation. At this time, the heat pipes 7 transfer the heat of the pump source assembly to the outside of the heat dissipation plate 6.

[0030] When the load is high, turn on the water pump and let the coolant flow through the water inlet pipe 8, the first branch channel 10, the second branch channel 11, the third branch channel 12, and the water outlet pipe 9 in sequence. When the coolant flows through the first branch channel 10, it is divided into six, and when it flows through the second branch channel 11, it is divided into twelve. The coolant enters the lower end of the upper pump source 4 and the lower end of the upper pump source 4 at the same time, and takes away the heat of the pump source assembly. Since the upper pump source 4 and the lower pump source 5 are arranged in an inclined manner, the heat pipe 7 and the second branch channel 11 do not interfere with each other, and the heat pipe 7 can also perform auxiliary heat dissipation at this time.

[0031] Since the second branch flow channel 11 is located inside the pump source assembly, when heat is dissipated only through the heat pipe 7, it is also necessary to keep the coolant inside the water pipe full. If there is residual gas in the second branch flow channel 11, it will affect the heat exchange between the heat pipe 7 and the pump source assembly, affecting the heat dissipation efficiency. Therefore, the above-mentioned non-opening of the water pipe assembly only refers to not opening the water pump.

[0032] The inclination angle of the upper pump source 4 is between 30° and 60°. If the inclination angle of the pump source is too small, the heat pipe 7 and the second branch flow channel 11 will conflict with each other; if the inclination angle is too large, on the one hand, the curvature of the pigtail is increased, affecting the laser generation effect of the pump source, and on the other hand, the contact area between the pump source and the heat pipe 7 is reduced in disguise, affecting the heat dissipation effect.

[0033] like Figures 3-4 As shown, the upper pump sources 4 are arranged in 2×4, the lower pump sources 5 correspond to the upper pump sources 4 one by one, and the lower pump sources 5 are located directly below the upper pump sources 4. This facilitates the arrangement of the heat dissipation channel. The upper pump source 4 includes a pump source K 11 , Pump source K 21 , Pump source K 31 , Pump source K 41 , Pump source K 51 , Pump source K 61 , Pump source K 71 , Pump source K 81 ; The lower pump source 5 includes a pump source K 12 , Pump source K 22 , Pump source K 32 , Pump source K 42 , Pump source K 52 , Pump source K 62 , Pump source K 72 , Pump source K 82 ;

[0034] The third branch flow channel 12 includes a branch flow channel S 1 , branch channel S 2 ;

[0035] To improve the heat dissipation effect and uniformity, it is necessary to make the coolant flow rates in different second branch channels 11 as the same as possible. That is, the resistance suffered by the coolant in different routes is roughly the same. Here, it can be simply understood that the lengths of different routes are roughly the same. Therefore, as shown in the figure, the branch channel S 1 and the branch channel S 2 converge around the middle.

[0036] Since the coolant will first make a right turn at the water inlet pipe, due to the influence of inertia and laminar flow, when the coolant enters the pump source K 11 、the pump source K 21 、the pump source K 31 、the pump source K 41 、the pump source K 12 、the pump source K 22 、the pump source K 32 、the pump source K 42 、the resistance of the corresponding second branch channel 11 will be greater than that of the second branch channel 11 when passing through the pump source K 51 、the pump source K 61 、the pump source K 71 、the pump source K 81 、the pump source K 52 、the pump source K 62 、the pump source K 72 、the pump source K 82 。

[0037] It has been verified that when the length of the branch channel S 1 is between 1.05 times and 1.15 times the length of the branch channel S 2 , the coolant flow rates are roughly the same. The flow rate of the pump source K 11 is 27.2 L / min; the flow rate of the pump source K 12 is 27.0 L / min; the flow rate of the pump source K 21 is 26.6 L / min; the flow rate of the pump source K 22 is 26.5 L / min; the flow rate of the pump source K 31 is 26.2 L / min; the flow rate of the pump source K 32 is 25.8 L / min; the flow rate of the pump source K 41 is 26.1 L / min; the flow rate of the pump source K 42 is 25.8 L / min; the flow rate of the pump source K 51 is 26.8 L / min; the flow rate of the pump source K 52 is 26.4 L / min; the flow rate of the pump source K 61 is 26.2 L / min; the flow rate of the pump source K 62 is 26.3 L / min; the flow rate of the pump source K 71The flow rate is 26.0L / min; the pump source K 72 The flow rate is 26.2L / min; the pump source K 81 The flow rate is 25.7L / min; the pump source K 82 The flow rate is 25.7L / min. It can be seen that the closer the pump source is to the water inlet pipe, the better the cooling effect of the coolant; and the farther the pump source is from the water inlet pipe 8, the worse the cooling effect of the coolant. However, due to the position of the heat pipe 7, the cooling effect of the heat pipe 7 is better when the pump source is farther away from the water inlet pipe 8, which makes up for the problem of uneven cooling effect caused by relying solely on water cooling.

[0038] The second branch flow channel 11 includes a plate-shaped cavity 13 in the pump source assembly and a shunt pipe 14 in the heat sink 6, and two shunt pipes 14 on the same side are connected to the cavity 13. The pump source is cooled by the coolant flowing in the cavity 13. The plate-shaped cavity 13 can increase the heat dissipation area of ​​the pump source heat source as much as possible under the premise of a certain coolant flow rate, thereby improving the heat dissipation effect.

[0039] The heat pipes 7 are arranged in 2×2, and the top surface of the heat pipe 7 located at the top is attached to the bottom surface of the upper pump source 4, and the bottom surface of the heat pipe 7 located at the bottom is attached to the top surface of the lower pump source 5. The heat pipe 7 can be attached to the pump source component in a direct contact manner, or it can be attached to the pump source component through a medium (heat sink 6). Regardless of the method, a phase change sheet or heat dissipation silicone grease should be provided between the pump source component and the heat pipe 7 to fill the gap and improve the heat dissipation effect.

[0040] The ends of the plurality of heat pipes 7 located outside the heat sink 6 are commonly connected to a plurality of fins 15. The fins 15 increase the contact area between the heat pipes 7 and the air, thereby improving the heat dissipation effect.

[0041] In order to facilitate ventilation and heat dissipation of the fins 15 and further improve the heat dissipation effect, a plurality of heat dissipation holes 16 for ventilation are opened at one end of the housing 1 close to the fins 15 .

[0042] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A tunable single-frequency pulsed fiber laser, comprising a housing (1), characterized in that: The housing (1) is provided with a pump source component, a gain component (2) and a resonant cavity component (3) from right to left in sequence. The pump source component comprises a plurality of upper pump sources (4) fixedly arranged on the top wall of the housing (1), and a plurality of lower pump sources (5) fixedly arranged on the bottom wall of the housing (1). The upper pump sources (4) are arranged in two rows in an oblique and symmetrical manner, and the tail fibers of the upper pump sources (4) face the middle of the gain component (2). The number and arrangement of the lower pump sources (5) are consistent with those of the upper pump sources (4). A heat sink (6) is provided in the middle of the housing (1), and the top surface of the heat sink (6) is simultaneously attached to all the upper pump sources (4), and the bottom surface is simultaneously attached to all the lower pump sources (5). A water pipe component and a plurality of heat pipes (7) are provided inside the heat sink (6), and both ends of the water pipe component extend to the outside of the housing (1); The water pipe assembly comprises a water inlet pipe (8), a water outlet pipe (9), a first branch flow channel (10), a second branch flow channel (11) and a third branch flow channel (12) which cooperate with each other, the second branch flow channel (11) located at the top extends to the lower end of the upper pump source (4), and the branch flow channel located at the bottom extends to the upper end of the lower pump source (5), and the coolant flows through the water inlet pipe (8), the first branch flow channel (10), the second branch flow channel (11), the third branch flow channel (12) and the water outlet pipe (9) in sequence; The heat pipe (7) is located between two second branch flow channels (11) on the same side, and one end of the heat pipe (7) away from the gain component (2) extends to the outside of the heat dissipation plate (6).

2. A tunable single-frequency pulsed fiber laser according to claim 1, characterized in that: The inclination angle of the upper pump source (4) is between 30° and 60°.

3. A tunable single-frequency pulsed fiber laser according to claim 2, characterized in that: The upper pump sources (4) are arranged in a 2×4 pattern, the lower pump sources (5) correspond to the upper pump sources (4) one by one, and the lower pump sources (5) are located directly below the upper pump sources (4).

4. The tunable single-frequency pulsed fiber laser according to claim 3, characterized in that: The second branch flow channel (11) comprises a plate-shaped cavity (13) in the pump source component and a shunt pipe (14) in the heat sink (6), and two shunt pipes (14) on the same side are connected to the cavity (13).

5. The tunable single-frequency pulsed fiber laser according to claim 3, characterized in that: The heat pipes (7) are arranged in a 2×2 pattern, and the top surface of the heat pipe (7) located at the top is in contact with the bottom surface of the upper pump source (4), and the bottom surface of the heat pipe (7) located at the bottom is in contact with the top surface of the lower pump source (5).

6. The tunable single-frequency pulsed fiber laser according to claim 5, characterized in that: One end of the plurality of heat pipes (7) located outside the heat dissipation plate (6) is commonly connected to a plurality of fins (15).

7. The tunable single-frequency pulsed fiber laser according to claim 6, characterized in that: A plurality of heat dissipation holes (16) are provided at one end of the housing (1) close to the fins (15).

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