An integrated semiconductor laser side pump module

Abstract

The present invention claims protection for an integrated semiconductor laser side pump module, belonging to the field of solid laser technology. The module is composed of a base, a semiconductor laser, a gain medium, a fixing glue, a wire, a ceramic insulating thermal pad, a metal thermal conductive sheet, a locking screw, a T-shaped insulating cap, a positive electrode, a negative electrode and other components. The semiconductor laser is located on the upper part of the base, and the pump light emitted by it is absorbed by the gain medium through the slit; the semiconductor lasers are connected to each other by wires, and two semiconductor lasers are used as a group of pumping units, and lateral staggered pumping is performed by selecting multiple groups of pumping units; there is a ceramic insulating thermal pad between the base and the semiconductor laser for insulation treatment, and the two side surfaces of the ceramic insulating thermal pad are respectively attached with metal thermal conductive sheets; compared with the traditional three-way annular side pump module, the present invention can accommodate more semiconductor lasers, has a more compact structure, a higher output laser power, and a linearly polarized laser output.

Description

Technical Field

[0001] The invention belongs to the field of laser technology, and in particular relates to an integrated semiconductor laser side pump module, which is particularly suitable for high-power solid lasers. Background Art

[0002] As the core device in all-solid-state lasers, semiconductor laser side pump modules have problems such as difficulty in efficient coupling of pump light, large size, and difficulty in eliminating redundant heat, which makes the realization of high-performance side pump modules particularly difficult. Currently, common side pump modules adopt a three-way annular side pumping method, and semiconductor lasers are symmetrically distributed outside the gain medium. Its structure and assembly process are relatively complex and inefficient. The present invention designs an integrated semiconductor laser side pumping module, which adopts a horizontal side pumping structure and a conduction cooling method, and has the characteristics of small size, high integration, high stability, high power and high efficiency. Summary of the invention

[0003] The present invention aims to solve the above problems of the prior art. An integrated semiconductor laser side pumping module is proposed. The technical solution of the present invention is as follows:

[0004] An integrated semiconductor laser side pumping module comprises: a base, a semiconductor laser, a gain medium, a fixing glue, a wire, a ceramic insulating thermal pad, a metal thermally conductive sheet, a locking screw, a T-shaped insulating cap, a positive electrode, a negative electrode, a slit and a Brewster angle, wherein the semiconductor laser is located on the upper part of the base, and the pumping light emitted by the semiconductor laser is absorbed by the gain medium through the slit; the semiconductor lasers are connected to each other through wires, and two semiconductor lasers are used as a group of pumping units, and lateral staggered pumping is performed by selecting multiple groups of pumping units; a ceramic insulating thermal pad is provided between the base and the semiconductor laser for insulation treatment, and metal thermally conductive sheets are respectively applied to the two side surfaces of the ceramic insulating thermal pad;

[0005] The base is used to carry all the components required for the module; the semiconductor laser is used as the pump source of the module; the gain medium is used to absorb the pump light generated by the semiconductor laser; the fixing glue is used to fix the gain medium in the cylindrical cavity on the base; the ceramic insulating thermal pad is placed between the semiconductor laser and the base to avoid short circuit; the metal thermal conductive sheet is used to connect the base, the ceramic insulating thermal pad and the semiconductor laser to ensure good heat conduction between them; the locking screw is used to fix the components on the base; the T-shaped insulating cap is nested on the locking screw to avoid short circuit between the locking screw and the semiconductor laser; the positive electrode and the negative electrode are the DC power supply interface of the module.

[0006] Furthermore, the base includes a plurality of screw fixing holes, a cylindrical cavity for placing the gain medium, and slits of equal width on both sides of the cylindrical cavity. Considering the influence of the divergence angle of the semiconductor laser, there are slits of a certain width on both sides of the cylindrical cavity on the base, and the slit width is between 250 and 400 μm; the edge of the base is provided with a limiting chamfer.

[0007] Furthermore, the semiconductor laser is composed of a single high-power bar or array, and two semiconductor lasers are used as a group of pumping units, and lateral staggered pumping is performed by selecting multiple groups of units; the semiconductor lasers are connected in series, and the heat generated is conducted away through the base; the wires are used to connect the positive electrodes and negative electrodes of multiple semiconductor lasers to support high current operation.

[0008] Furthermore, both ends of the gain medium are cut into Brewster angles, and the gain medium is selected from Nd:YVO4 crystal, Nd:YLF crystal, Nd:YAG crystal, and Nd:KGW crystal; the concentration of doped Nd ions is between 0.4% and 1.2%, and the deviation value of the Brewster angle is less than 0.5°; as the gain medium of the side pump module, the gain medium is fixed in a cylindrical cavity on the base, and the long axis of its end face needs to be kept horizontal.

[0009] Furthermore, the fixing glue is selected from high-temperature thermally conductive transparent glue, and is made of silicone, polyurethane thermally conductive glue, epoxy resin AB glue, and ultraviolet glue.

[0010] Furthermore, the material of the ceramic insulating thermal pad is selected from alumina, zirconium oxide, aluminum silicate, and aluminum nitride. The ceramic insulating thermal pad has a square structure with a plurality of screw holes of the same diameter on the edge and is fixed to the base by locking screws.

[0011] Furthermore, the material of the metal thermally conductive sheet is a metal or alloy material with high thermal conductivity, and the thickness ranges from 0.01 to 3 mm; based on the needs of heat conduction, metal thermally conductive sheets are required to fill the gaps between the base and the ceramic insulating thermal pad, and between the semiconductor laser and the ceramic insulating thermal pad.

[0012] Furthermore, the locking screw is used to fix components including semiconductor lasers, ceramic insulating thermal pads, and metal thermal conductive sheets. The locking screw is also used to finely adjust the locking screw torque so that the light line of the semiconductor laser is accurately aligned with the slit, thereby increasing the coupling efficiency of the pump light.

[0013] Furthermore, the T-shaped insulating cap is nested on the locking screw, which can achieve insulation functions in both horizontal and vertical directions to avoid short circuit between the locking screw and the semiconductor laser. Its material can be plastic, nylon, rubber, etc.

[0014] Furthermore, the positive electrode and the negative electrode are power supply interfaces of the side pump module, which are used to connect to a DC power supply, and the connected power supply is a continuous or pulse switching power supply with constant current and adaptive voltage.

[0015] The advantages and beneficial effects of the present invention are as follows:

[0016] The present invention is an integrated semiconductor laser side pump module. The pump light emitted by the semiconductor laser is coupled into a cylindrical cavity containing a gain medium through a slit. The gain medium absorbs the pump light and generates a large number of inverted particles, forming a laser side pump module with an amplification function. The significant advantages are:

[0017] 1. The semiconductor laser in this module can be assembled in a large-scale integrated manner, which can greatly improve the output power and be more widely used in high-power solid-state lasers.

[0018] 2. The side pump module couples the pump light emitted by the semiconductor laser into the gain medium through a slit, and the gain medium absorbs the pump light. The center of the slit is at the same height as the light-emitting point of the semiconductor laser, and the cylindrical cavity is used to place the gain medium. Compared with the ring pump structure, this module is miniaturized, more compact, and less difficult to assemble. The semiconductor lasers are connected to each other through wires, and two semiconductor lasers are used as a group of pump units. By selecting multiple groups of pump units for lateral staggered pumping, an integrated semiconductor laser side pumping structure can be realized.

[0019] 3. The module adopts conduction cooling, and the heat dissipation structure is simple and effective.

[0020] 4. The aperture of the cylindrical cavity better fits the size of the gain medium, and the polishing coating process is used to reflect the uncollected pump light multiple times, thereby improving the pump light absorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of an integrated semiconductor laser side pump module according to a preferred embodiment of the present invention.

[0022] Figure 2 An exploded view of the side pump module of an integrated semiconductor laser.

[0023] Figure 3 Schematic diagram of a Nd:YAG crystal rod with both ends cut into Brewster angles, where α is the Brewster angle.

[0024] The markings in the figure are: 1. base, 2. semiconductor laser, 3. gain medium, 4. fixing glue, 5. wire, 6. ceramic insulating thermal pad, 7. metal thermal conductive sheet, 8. locking screw, 9. T-shaped insulating cap, 10. positive electrode, 11. negative electrode, 12. slit, 13. Brewster angle. DETAILED DESCRIPTION

[0025] The following will describe the technical solutions in the embodiments of the present invention in detail in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention.

[0026] The technical solution of the present invention to solve the above technical problems is:

[0027] An integrated semiconductor side pump module, such as Figure 1 As shown, it includes a base 1, a semiconductor laser 2, a gain medium 3, a fixing glue 4, a wire 5 connecting the semiconductor laser electrodes, a ceramic insulating thermal pad 6, a metal thermally conductive sheet 7, a locking screw 8, a T-shaped insulating cap 9, a positive electrode 10, a negative electrode 11, a slit 12, and a Brewster angle 13. The base 1 includes a cylindrical cavity and a slit 12 that match the size of the gain medium 3; the semiconductor laser 2 is located on the upper part of the base 1, and the pump light emitted by it is absorbed by the gain medium 3 through the slit 12. The semiconductor lasers 2 are connected to each other through a wire 5, and two semiconductor lasers 2 are used as a group of pumping units, and lateral staggered pumping is performed by selecting multiple groups of pumping units; there is a ceramic insulating thermal pad 6 between the base 1 and the semiconductor laser 2 for insulation treatment, and metal thermally conductive sheets 7 are respectively applied to the two side surfaces of the ceramic insulating thermal pad 6 to reduce thermal resistance.

[0028] Preferably, the base 1 includes a plurality of screw fixing holes, a cylindrical cavity for placing the gain medium 3, and slits 12 of equal width on both sides of the cylindrical cavity. Considering the influence of the divergence angle of the semiconductor laser 2, there are slits 12 of a certain width on both sides of the cylindrical cavity on the base 1, and the slit width is between 250 and 400 μm. The pump light emitted by the semiconductor laser 2 is incident into the gain medium 3 through the slit 12. The material of the base 1 can be copper, stainless steel or other metal materials with good thermal conductivity. The edge of the base 1 is provided with a limited chamfer. Considering that the roughness of the surface of the base 1 will affect the thermal conductivity, the surface and the cylindrical cavity thereof need to be polished so that the base 1 fits better with other components, thereby reducing thermal resistance. In order to improve the anti-oxidation ability of the module, the module is first polished and then surface electroplated. The applicable electroplating material is a metal with good oxidation resistance, such as gold or alloy materials.

[0029] Preferably, the semiconductor laser 2 is composed of a single high-power bar or array. Since the side pumping efficiency of a single semiconductor laser 2 is low, two semiconductor lasers 2 are used as a group of pumping units, and multiple groups of units are selected for lateral staggered pumping. The semiconductor lasers 2 are connected in series, and the heat generated is conducted away through the base. The module also supports the working mode of more groups of pumping units.

[0030] Preferably, both ends of the gain medium 3 are cut into Brewster angles 13. The gain medium can be Nd:YVO4 crystal, Nd:YLF crystal, Nd:YAG crystal, Nd:KGW crystal, etc. The concentration of doped Nd ions is between 0.4% and 1.2%, and the deviation value of the Brewster angle is less than 0.5°. As the gain medium of the side pump module, the gain medium 3 is fixed in the cylindrical cavity on the base 1, and the long axis of its end face needs to be kept horizontal.

[0031] Preferably, the fixing glue 4 is a high-temperature thermally conductive transparent glue, which can be silicone, polyurethane thermally conductive glue, epoxy resin AB glue, UV glue, etc., which is characterized by high temperature resistance, high stability, easy curing, and good light transmittance.

[0032] The wire 5 is used to connect the positive electrodes 10 and the negative electrodes 11 of a plurality of semiconductor lasers 2, and supports high current operation (40-60A).

[0033] Preferably, the ceramic insulating thermal pad 6 can be made of alumina, zirconium oxide, aluminum silicate, aluminum nitride, etc. It is characterized by high temperature resistance, high thermal conductivity, and good insulation, and is suitable for heat dissipation of high-power devices. The ceramic insulating thermal pad 6 has a square structure, and has a plurality of screw holes of the same diameter on the border, and is fixed to the base 1 by locking screws 8.

[0034] Preferably, the metal thermally conductive sheet 7 is made of a metal or alloy material with high thermal conductivity, such as indium foil or tin foil, and has a thickness ranging from 0.01 to 3 mm. Based on the need for heat conduction, the metal thermally conductive sheet 7 is required to fill the gaps between the base 1 and the ceramic insulating thermally conductive pad 6 and between the semiconductor laser 2 and the ceramic insulating thermally conductive pad 6, so that the base, the ceramic insulating thermally conductive pad and the semiconductor laser fit more closely and reduce thermal resistance.

[0035] Preferably, the locking screw 8 is used to fix components such as the semiconductor laser 2, the ceramic insulating thermal pad 6, and the metal thermal conductive sheet 7. In addition to fixing the components, it can also finely adjust the locking screw torque to accurately align the light line of the semiconductor laser 2 with the slit 12, thereby increasing the coupling efficiency of the pump light.

[0036] Preferably, the T-shaped insulating cap 9 is nested on the locking screw 8 to achieve insulation functions in both horizontal and vertical directions to avoid short circuit between the locking screw 8 and the semiconductor laser 2. Its material can be plastic, nylon, rubber, etc.

[0037] Preferably, the positive electrode 10 and the negative electrode 11 are power supply interfaces of the side pump module, and can be connected to a high-power DC power supply, and the connected power supply can be a continuous or pulse switching power supply with constant current and adaptive voltage.

[0038] The following are specific embodiments: Preferred embodiment 1: As a preferred embodiment, the base 1 adopts a copper base, the semiconductor laser 2 adopts a 60W semiconductor laser, the gain medium 3 adopts a Nd:YAG crystal rod, the fixing glue 4 adopts PDMS glue, the ceramic insulating thermal pad 6 adopts an alumina ceramic gasket, the metal thermal conductive sheet 7 adopts an indium foil, and the gain medium end face 13 adopts a Nd:YAG crystal rod end face. The semiconductor laser side pump module, the 60W semiconductor laser is connected by a wire, and the positive electrode and the negative electrode are connected to the power supply. The 60W semiconductor lasers are symmetrically distributed on both sides of the Nd:YAG crystal rod for side pumping, two 60W semiconductor lasers are selected as a group of pumping units, and three groups of pumping units are used to complete the integrated side pumping module structure; the Nd:YAG crystal rod is located in the cylindrical cavity of the copper base, and the Nd:YAG crystal rod is fixed with PDMS glue.

[0039] Furthermore, in the 60W semiconductor laser side pump module, a T-shaped insulating cap 9 is added between the locking screw 8 and the 60W semiconductor laser 2, and the T-shaped insulating cap 9 is used to avoid a short circuit between the locking screw 8 and the 60W semiconductor laser 2. There is an indium foil 7 between the 60W semiconductor laser 2 and the copper base 1, so that the copper base 1 and the 60W semiconductor laser 2 fit more closely and reduce thermal resistance. The alumina ceramic gasket 6 is located on the upper part of the copper base 1; the indium foil 7 fits tightly with the 60W semiconductor laser 2.

[0040] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separable, and the components shown as units may or may not be physical units, i.e., they may be located in one place or distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0041] In order to improve the output power of the pump laser and realize the function of integrated installation of the semiconductor laser side pump module, the present invention proposes an integrated semiconductor laser side pump module structure, in which the semiconductor laser of the module is placed horizontally on the upper part of the base, two semiconductor lasers are used as a group of pump units, and multiple groups of pump units are connected in series with wires to realize high-power operation of the side pump module. Not only can large-scale integrated assembly be realized, but multiple pump units can also be expanded to realize a higher-power integrated side pump module.

[0042] The present invention realizes an integrated semiconductor laser side pump module, wherein the integrated side pump module comprises a base, a semiconductor laser, a gain medium, a fixing glue, a wire connecting the semiconductor laser electrode, a ceramic insulating thermal pad, a metal thermal conductive sheet, a locking screw, a T-shaped insulating cap, a positive electrode, and a negative electrode. While completing the integrated design of the side pump module, this module also takes into account the heat dissipation of the side pump module and the influence of the surface roughness. The module is easy to realize high-power operation and has a compact structure.

[0043] Furthermore, the base of the integrated semiconductor laser side pumping module includes a plurality of screw fixing holes, a cylindrical cavity for placing the gain medium, and narrow slits on both sides of the cylindrical cavity. The semiconductor laser is fixed on the base by locking screws.

[0044] The gain medium end face is cut into a Brewster angle to generate linear polarized light and avoid parasitic oscillation. The gain medium is placed in the cylindrical cavity of the base, and a fixing glue is applied on the surface of the gain medium to bond it to the inner wall of the cylindrical cavity.

[0045] The ceramic insulating thermal pad of the integrated semiconductor laser side pump module has the main functions of insulation and heat conduction. The ceramic insulating thermal pad can achieve insulation between the semiconductor laser and the base, and has high temperature resistance, high insulation and thermal conductivity. Its thermal conductivity range is 30W / (m·K) to 150W / (m·K). In addition, the ceramic insulating thermal pad has a large hardness and is not easy to deform, so it is suitable for use as a high-stability gasket.

[0046] The metal heat-conducting sheet material of the integrated semiconductor laser side pump module has high thermal conductivity, such as indium foil or tin foil. The metal heat-conducting sheet is closely attached between the base and the ceramic insulation heat-conducting pad and between the semiconductor laser and the ceramic insulation heat-conducting pad.

[0047] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0048] The above embodiments should be understood to be only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the contents of the present invention, technicians can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. An integrated semiconductor laser side pump module, characterized in that: include: A base, a semiconductor laser, a gain medium, a fixing glue, a wire, a ceramic insulating thermal pad, a metal thermally conductive sheet, a locking screw, a T-shaped insulating cap, a positive electrode, a negative electrode, a slit and a Brewster angle. The semiconductor laser is located on the upper part of the base, and the pump light emitted by the semiconductor laser is absorbed by the gain medium through the slit. The semiconductor lasers are connected to each other through wires, and two semiconductor lasers are used as a group of pumping units. Lateral staggered pumping is performed by selecting multiple groups of pumping units. There is a ceramic insulating thermal pad between the base and the semiconductor laser for insulation treatment, and metal thermal conductive sheets are respectively applied to the two side surfaces of the ceramic insulating thermal pad; the base is used to carry all the components required for the module; the semiconductor laser is used as the pump source of the module; The gain medium is used to absorb the pump light generated by the semiconductor laser; the fixing glue is used to fix the gain medium in the cylindrical cavity on the base; the ceramic insulating thermal pad is placed between the semiconductor laser and the base to avoid short circuit; The metal thermal conductive sheet is used to connect the base, ceramic insulating thermal pad and semiconductor laser to ensure good heat conduction between them; the locking screw is used to fix the components on the base; the T-shaped insulating cap is nested on the locking screw to avoid short circuit between the locking screw and the semiconductor laser; the positive electrode and the negative electrode are the DC power supply interface of the module.

2. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The base includes a plurality of screw fixing holes, a cylindrical cavity for placing a gain medium, and slits of equal width on both sides of the cylindrical cavity. Considering the influence of the divergence angle of the semiconductor laser, there are slits of a certain width on both sides of the cylindrical cavity on the base, and the slit width is between 250 and 400 μm; the edge of the base is provided with a limiting chamfer.

3. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The semiconductor laser is composed of a single high-power bar or array, and two semiconductor lasers are used as a group of pumping units, and lateral staggered pumping is performed by selecting multiple groups of units; The semiconductor lasers are connected in series, and the heat generated is conducted away through the base; the wires are used to connect the positive and negative electrodes of multiple semiconductor lasers to support high current operation.

4. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The two ends of the gain medium are cut into Brewster angles, and the gain medium is selected from Nd:YVO4 crystal, Nd:YLF crystal, Nd:YAG crystal, and Nd:KGW crystal; the concentration of doped Nd ions is between 0.4% and 1.2%, and the deviation value of the Brewster angle is less than 0.5°; as the gain medium of the side pump module, the gain medium is fixed in a cylindrical cavity on a base, and the long axis of its end face needs to be kept horizontal.

5. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The fixing glue is selected from high-temperature thermally conductive transparent glue, and is made of silicone, polyurethane thermally conductive glue, epoxy resin AB glue, and ultraviolet glue.

6. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The material of the ceramic insulating thermal pad is selected from alumina, zirconium oxide, aluminum silicate, and aluminum nitride. The ceramic insulating thermal pad has a square structure, and has a plurality of screw holes of the same diameter on the edge, and is fixed to the base by locking screws.

7. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The material of the metal thermal conductive sheet is a metal or alloy material with high thermal conductivity, and the thickness ranges from 0.01 to 3 mm. Based on the needs of heat conduction, the metal thermal conductive sheet is required to fill the gaps between the base and the ceramic insulating thermal conductive pad, and between the semiconductor laser and the ceramic insulating thermal conductive pad.

8. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The locking screw is used to fix components including semiconductor lasers, ceramic insulating thermal pads, and metal thermal conductive sheets. The locking screw is also used to finely adjust the locking screw torque so that the light line of the semiconductor laser is accurately aligned with the slit, thereby increasing the coupling efficiency of the pump light.

9. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The T-shaped insulating cap is nested on the locking screw and can achieve insulation functions in both horizontal and vertical directions to avoid short circuit between the locking screw and the semiconductor laser. The material of the T-shaped insulating cap is plastic, nylon, or rubber.

10. The integrated semiconductor laser side pump module according to claim 1, characterized in that: The positive electrode and the negative electrode are power supply interfaces of the side pump module, and are used to connect to a DC power supply, and the connected power supply is a continuous or pulse switching power supply with constant current and adaptive voltage.

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