A method for manufacturing a high power quantum cascade laser

Abstract

The application relates to the technical field of lasers, in particular to a preparation method of a high-power quantum cascade laser, which comprises the following steps: forming a stack structure, the stack structure comprising a first part and second parts located on both sides of the first part, the first part corresponding to an active layer, an upper waveguide layer, an upper cladding layer, a cover layer and a part of a lower waveguide layer which are used to form a waveguide structure; patterning the stack structure to form the waveguide structure; wherein, before forming the waveguide structure or after forming the waveguide structure, a first mask layer with an injection window is formed on a surface of the cover layer away from the upper cladding layer, the injection window exposes the second part, ion implantation is carried out through the injection window to form an insulating region in the part of the waveguide structure adjacent to the second part and in the part of the second part away from the substrate; after forming the waveguide structure with the insulating region, a first electrode layer is formed on the insulating region. The application is at least beneficial to reducing the preparation difficulty and preparation cost of the high-power quantum cascade laser.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, and particularly relates to a method for fabricating a high-power quantum cascade laser. Background Technology

[0002] Quantum cascade lasers (QCLs) are semiconductor lasers that achieve laser output based on inter-subband transitions. Their advent has opened up a new field of semiconductor lasers in the mid- and far-infrared and terahertz bands, and they have been widely used in many fields such as industry, agriculture, medicine, environmental protection and defense, becoming an important infrared laser source for transmission and detection applications.

[0003] Quantum cascade lasers typically operate under high bias and high current densities. Combined with the extremely low thermal conductivity of the superlattice structure in the active region, this leads to the easy generation and accumulation of significant heat within the laser. If the waveguide structure is poorly designed, this heat cannot be dissipated effectively, resulting in a rapid increase in the active region temperature, an increase in the threshold current density, and a decrease in conversion efficiency and maximum output power. Currently, due to these limitations, the switching current of quantum cascade lasers operating continuously at room temperature can reach the ampere level.

[0004] Currently, strategies for reducing the temperature of the active region mainly fall into two categories: reducing heat generation and enhancing heat dissipation. Driving a quantum cascade laser with pulsed current is one important method for reducing heat generation. Pulsed pump current can shorten the laser's operating time per unit time, thereby reducing heat accumulation. Methods to improve heat dissipation efficiency include: forming Fe-doped InP secondary epitaxy in the trenches on both sides of the ridge waveguide, electroplating gold on the top electrode, and using flip-chip packaging. The common goal of these techniques is to increase the contact area between the ridge waveguide structure and the high thermal conductivity material, thereby increasing the lateral heat dissipation capacity of the ridge waveguide structure and dissipating heat from the active region more efficiently.

[0005] Driving quantum cascade lasers with pulsed currents can indeed significantly reduce heat generation, but because the laser operates in pulsed current mode, its average output power is much lower than that in continuous mode under the same current conditions. Doping Fe with InP in the trenches on both sides of the ridge waveguide is an effective way to improve heat dissipation. Compared to traditional materials such as SiO2 (thermal conductivity of SiO2 is approximately 1.4 W / m·K) or silicon nitride (thermal conductivity of silicon nitride is approximately 50 W / m·K), Fe-doped InP has a thermal conductivity as high as approximately 68 W / m·K. Studies have shown that quantum cascade lasers fabricated using this technique can achieve approximately three times the highest continuous output power at room temperature. However, this technique faces challenges due to its high time and economic costs, requiring comprehensive consideration of cost factors in its application. Electroplating gold and flip-chip bonding have become common methods in the fabrication of quantum cascade lasers, especially in the manufacture of high-power lasers, where increasing output power is almost inseparable from these two processes.

[0006] The overheating problem in the active region of quantum cascade lasers is a major bottleneck limiting their maximum output power. Therefore, improving heat dissipation to further increase output power is crucial for their future development. Summary of the Invention

[0007] In view of this, the present invention aims to provide a method for fabricating a high-power quantum cascade laser, which can significantly improve the heat dissipation capability of the quantum cascade laser and has a relatively simple process, thereby maximizing the maximum output power of the laser.

[0008] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0009] This invention provides a method for fabricating a high-power quantum cascade laser, comprising: forming a substrate, a buffer layer, a lower waveguide layer, an active layer, an upper waveguide layer, an upper cladding layer, and a capping layer sequentially stacked along a first direction to form a stacked structure, the stacked structure including a first part and a second part located on both sides of the first part, the active layer, upper waveguide layer, upper cladding layer, capping layer, and a lower waveguide layer of a certain thickness corresponding to the first part being used to form a waveguide structure; patterning the stacked structure and removing the second part of a certain thickness to form a waveguide structure; wherein, before or after forming the waveguide structure, a first mask layer with an injection window is formed on the surface of the capping layer away from the upper cladding layer, the injection window exposing the second part, and ion implantation is performed through the injection window to form an insulating region in the waveguide structure of a certain thickness adjacent to the second part and in the second part of a certain thickness away from the substrate; after forming the waveguide structure with the insulating region, a first electrode layer is formed on the insulating region and on the top surface of the waveguide structure.

[0010] Furthermore, the implanted ions in the ion implantation step include at least one of hydrogen ions, helium ions, nitrogen ions, or argon ions.

[0011] Furthermore, the step of forming an insulating region before forming the waveguide structure includes: forming a first mask layer on the top surface of the stacked structure, exposing a second portion through an implantation window, performing ion implantation through the implantation window, wherein the ion implantation depth is greater than the total thickness of the active layer, upper waveguide layer, upper cladding layer and capping layer along a first direction, and the ion implantation depth is less than the total thickness of the lower waveguide layer, active layer, upper waveguide layer, upper cladding layer and capping layer.

[0012] Furthermore, the ion implantation direction is the first direction.

[0013] Furthermore, the step of forming an insulating region after forming the waveguide structure includes: forming a first mask layer on the top surface of the waveguide structure, the first mask layer exposing the remaining second part and the side surface of the waveguide structure, and ion implantation including a first implantation process in a first implantation direction and a second implantation process in a second implantation direction, the angle between the first implantation direction and the second implantation direction is 90°, and the angle between the first implantation direction and the first direction is 45°, and the angle between the second implantation direction and the first direction is 45°.

[0014] Furthermore, the thickness of the insulating region within the waveguide structure is in the range of 0.9 μm to 1.1 μm.

[0015] Furthermore, the step of patterning the stacked structure to form a waveguide structure before forming the insulating region includes: forming a second mask layer with an etching window on the first portion, the etching window exposing the top surface of the second portion, and removing the capping layer, upper cladding layer, upper waveguide layer, active layer and a portion of the thickness of the lower waveguide layer located in the second portion through the etching window to form the waveguide structure.

[0016] Furthermore, the first mask layer is a dielectric layer. The step of forming the first mask layer after forming the waveguide structure includes: the second mask layer is a photoresist layer, the second mask layer is removed, an initial first mask layer is formed on the top surface of the remaining second part and the surface of the waveguide structure, the initial first mask layer is then removed from the side surface of the waveguide structure and the second part, and the remaining initial first mask layer is used as the first mask layer; or, the second mask layer is a dielectric layer, and the second mask layer is used as the first mask layer.

[0017] Furthermore, the step of patterning the stacked structure after forming the insulating region to form the waveguide structure includes: removing the first mask layer, forming a photoresist layer on the top surface of the first portion, the photoresist layer having an etching window exposing the second portion, removing the capping layer, upper cladding layer, upper waveguide layer, active layer and a portion of the lower waveguide layer located in the second portion through the etching window to form the waveguide structure, and then removing the photoresist layer; or, forming a photoresist layer on the top surface of the first mask layer, the photoresist layer having an etching window exposing the second portion, removing the capping layer, upper cladding layer, upper waveguide layer, active layer and a portion of the lower waveguide layer located in the second portion through the etching window to form the waveguide structure, and then removing the photoresist layer and the first mask layer.

[0018] Furthermore, the ion implantation energy is in the range of 50 keV to 500 keV, and the implantation dose is in the range of 2E12cm. -2 ~5E15cm -2 Within the range.

[0019] Compared with the prior art, the present invention can achieve the following beneficial effects: The method for fabricating a high-power quantum cascade laser provided by the present invention treats the ridge waveguide of the semiconductor laser by means of ion implantation, so that the laser surface except for the top of the ridge waveguide structure is electrically insulated. Specifically, the characteristic of ion implantation to reduce the carrier mobility of semiconductor materials is used to form an insulating region, thereby forming a surface structure similar to the ridge waveguide of a traditional quantum cascade laser, but without the need to grow an electrically insulating film, but instead using ion implantation to form an insulating region in the semiconductor material. Because this method does not use a dielectric film to achieve electrical insulation, but instead achieves electrical insulation through the material body after ion implantation, the waveguide structure can directly contact the first electrode layer. The first electrode layer is usually a metal with high thermal conductivity, such as gold (the thermal conductivity of gold is 320 W / m·K). This avoids the influence of forming a dielectric film on heat dissipation, significantly enhances the heat dissipation capacity of the waveguide structure, and thus greatly improves the overall performance of the device, especially its maximum output power. In addition, compared with the method of forming secondary epitaxy (Fe-doped InP), the fabrication method of high-power quantum cascade laser provided by this invention achieves heat dissipation effects close to or even higher while significantly reducing process complexity and process cost. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 A schematic diagram of the structure of the high-power quantum cascade laser described in the embodiments of the present invention;

[0022] Figure 2 A schematic flowchart of the first method for fabricating a high-power quantum cascade laser according to an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of each step in a method for fabricating a high-power quantum cascade laser according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic flowchart of a second method for fabricating a high-power quantum cascade laser according to an embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] This invention provides a method for fabricating a high-power quantum cascade laser, used for preparing... Figure 1 The high-power quantum cascade laser described herein, the fabrication method of the high-power quantum cascade laser includes: forming a substrate 9, a buffer layer 8, a lower waveguide layer 7, an active layer 5, an upper waveguide layer 4, an upper cladding layer 3, and a capping layer 2 sequentially stacked along a first direction X to form a stacked structure, the stacked structure including a first part I and a second part II located on both sides of the first part I, the active layer 5, the upper waveguide layer 4, the upper cladding layer 3, the capping layer 2, and the lower waveguide layer 7 of a certain thickness corresponding to the first part I are used to form a waveguide structure; patterning the stacked structure, removing a portion of the thickness... The second part II is used to form a waveguide structure. Before or after the waveguide structure is formed, a first mask layer 14 with an implantation window is formed on the surface of the capping layer 2 away from the upper cladding layer 3. The implantation window exposes the second part II. Ion implantation is performed through the implantation window to form an insulating region 6 in the waveguide structure with a partial thickness adjacent to the second part II and in the second part II with a partial thickness away from the substrate 9. After the waveguide structure with the insulating region 6 is formed, a first electrode layer 1 is formed on the insulating region 6 and on the top surface of the waveguide structure.

[0031] It should be noted that by precisely controlling the energy, beam density, annealing temperature, and time of ion implantation, the concentration and depth of implanted ions can be effectively controlled, thereby minimizing the potential damage to each layer of material caused by ion implantation.

[0032] Furthermore, the implanted ions in the ion implantation step include at least one of hydrogen ions, helium ions, nitrogen ions, or argon ions, with hydrogen ions being preferred.

[0033] This invention provides two methods for fabricating high-power quantum cascade lasers, as described in the following embodiments. Figure 2 The first method involves forming an insulating region 6 before forming the waveguide structure, as shown in the reference. Figure 3 and Figure 4 The second method involves forming an insulating region 6 after the waveguide structure is formed. These two methods will be explained in detail below.

[0034] For the first approach, a substrate 9, a buffer layer 8, a lower waveguide layer 7, an active layer 5, an upper waveguide layer 4, an upper cladding layer 3, and a capping layer 2 are first stacked sequentially along the first direction X to form a stacked structure. The stacked structure includes a first part I and a second part II located on both sides of the first part I. The active layer 5, the upper waveguide layer 4, the upper cladding layer 3, the capping layer 2, and a portion of the thickness of the lower waveguide layer 7 corresponding to the first part I are used to form the waveguide structure. Further, the step of forming the insulating region 6 before forming the waveguide structure includes: forming a first mask layer 14 on the top surface of the stacked structure, exposing the second part II through the implantation window, and performing ion implantation through the implantation window along the first direction X. The ion implantation depth is greater than the total thickness of the active layer 5, the upper waveguide layer 4, the upper cladding layer 3, and the capping layer 2, and the ion implantation depth is less than the total thickness of the lower waveguide layer 7, the active layer 5, the upper waveguide layer 4, the upper cladding layer 3, and the capping layer 2.

[0035] Furthermore, the ion implantation direction is the first direction X.

[0036] Furthermore, the step of patterning the stacked structure after forming the insulating region 6 to form the waveguide structure includes: removing the first mask layer 14, forming a photoresist layer on the top surface of the first part I, the photoresist layer having an etching window exposing the second part II, removing the capping layer 2, upper cladding layer 3, upper waveguide layer 4, active layer 5 and a partial thickness of lower waveguide layer 7 located in the second part II through the etching window to form the waveguide structure, and then removing the photoresist layer; or, forming a photoresist layer on the top surface of the first mask layer 14, the photoresist layer having an etching window exposing the second part II, removing the capping layer 2, upper cladding layer 3, upper waveguide layer 4, active layer 5 and a partial thickness of lower waveguide layer 7 located in the second part II through the etching window to form the waveguide structure, and then removing the photoresist layer and the first mask layer 14.

[0037] In some examples, a 2 μm thick silicon oxide layer is deposited on the top surface of the stacked structure (the surface of the capping layer 2 away from the upper cladding layer 3) using plasma chemical vapor deposition. After the silicon oxide layer is grown, a pattern for ion implantation is formed on the silicon oxide layer using photolithography, i.e., the first mask layer 14 is formed. Then, ion implantation is performed on the stacked structure. The ion implantation energy can be 100 keV, the implanted ion type can be hydrogen ions, the implantation angle is 0° (corresponding to the implantation direction is the first direction X), and the ion implantation depth must penetrate the active layer 5. Subsequently, photolithography is performed again to etch the stacked structure to form a waveguide structure. Finally, the first electrode layer 1 is grown, the substrate 9 is thinned, and the second electrode layer 10 is grown on the back side of the substrate 9.

[0038] For the second method, refer to Figure 3 and Figure 4First, a substrate 9, a buffer layer 8, a lower waveguide layer 7, an active layer 5, an upper waveguide layer 4, an upper cladding layer 3, and a capping layer 2 are sequentially stacked along the first direction X to form a stacked structure. The stacked structure includes a first part I and a second part II located on both sides of the first part I. The active layer 5, the upper waveguide layer 4, the upper cladding layer 3, the capping layer 2, and the lower waveguide layer 7 of a certain thickness corresponding to the first part I are used to form the waveguide structure.

[0039] Furthermore, the step of patterning the stacked structure to form the waveguide structure before forming the insulating region 6 includes: referencing Figure 3 A second mask layer 11 with an etching window is formed on the first part I, the etching window exposing the top surface of the second part II. The capping layer 2, upper cladding layer 3, upper waveguide layer 4, active layer 5 and a partial thickness of lower waveguide layer 7 located in the second part II are removed through the etching window to form a waveguide structure.

[0040] Furthermore, the step of forming the insulating region 6 after forming the waveguide structure includes: forming a first mask layer 14 on the top surface of the waveguide structure, the first mask layer 14 exposing the remaining second part II and the side surface of the waveguide structure, and ion implantation including a first implantation process in a first implantation direction and a second implantation process in a second implantation direction, the angle between the first implantation direction and the second implantation direction is 90°, and the angle between the first implantation direction and the first direction X is 45°, and the angle between the second implantation direction and the first direction X is 45°.

[0041] Furthermore, the thickness of the insulating region 6 within the waveguide structure is in the range of 0.9 μm to 1.1 μm.

[0042] Furthermore, the first mask layer 14 is a dielectric layer, and the steps for forming the first mask layer 14 after forming the waveguide structure include: (Refer to...) Figure 3 The second mask layer 11 is a photoresist layer. The second mask layer 11 is removed, and an initial first mask layer 12 is formed on the top surface of the remaining second part II and the surface of the waveguide structure. The initial first mask layer 12 on the side of the waveguide structure and the second part II is then removed, and the remaining initial first mask layer 12 is used as the first mask layer 14.

[0043] In some other embodiments, the first mask layer 14 is a silicon oxide layer and the second mask layer 11 is a dielectric layer. The step of forming the first mask layer 14 after forming the waveguide structure includes: using the second mask layer 11 as the first mask layer 14.

[0044] In some embodiments, the dielectric layer is a silicon oxide layer or a silicon nitride layer.

[0045] In some examples, the initial first mask layer 12 has a thickness of 2 μm. The initial first mask layer 12 can be grown using plasma-enhanced chemical vapor deposition. After the initial first mask layer 12 is grown, it is etched using photolithography to form a pattern for ion implantation. Subsequently, ion implantation is performed. The implantation energy can be 100 keV, the implanted ion type can be hydrogen ions, the implantation depth can be about 1 μm, and the implantation is performed twice. The two implantations are performed on both sides of the waveguide structure at an implantation angle of 45°, thereby forming the insulating region 6. After the insulating region 6 is formed, the remaining areas except the top of the waveguide structure are insulated. Finally, the growth of the first electrode layer 1 is completed, and the second electrode layer 10 is grown on the back side of the substrate 9 after thinning.

[0046] In some embodiments of the two methods described above, the ion implantation energy is in the range of 50 keV to 500 keV, and the implantation dose is 2E12cm. -2 ~5E15cm -2 Within the range.

[0047] For the two methods described above, in some examples, the thickness of the first electrode layer 1 is 300 nm, and the material of the first electrode layer 1 includes gold; in some examples, the material of the capping layer 2 is N-type InP, and the thickness of the capping layer 2 is 200 nm; in some examples, the material of the upper cladding layer 3 is N-type InP, and the thickness of the upper cladding layer 3 is 1.5 μm; in some examples, the material of the upper waveguide layer 4 is N-type InP, and the thickness of the upper waveguide layer 4 is 1.5 μm; in some examples, the thickness of the active layer 5 is 200 nm, and the active layer may include a barrier layer and 40 lattice-matched and periodically arranged In... 0.53 Ga 0.47 As and In 0.52 Al 0.48 As composition; in some examples, the thickness of insulating region 6 is 1 μm; in some examples, the material of lower waveguide layer 7 includes N-type InP, and the thickness of lower waveguide layer 7 is 5 μm; in some examples, buffer layer 8 is a 1.5 μm thick N-type InP layer; in some examples, substrate 9 is an N-type InP layer; in some examples, the thickness of second electrode layer 10 is 300 nm.

[0048] This invention utilizes the waveguide structure's material body for electrical insulation, eliminating the need for additional electrically insulating film growth. This avoids short-circuit problems that may arise from incomplete or excessively thin electrically insulating layers on the sidewalls. Furthermore, it eliminates the need for additional photolithography etching steps for the electrically insulating layer, simplifying the fabrication process and improving device stability. Since no electrically insulating layer is required, the waveguide structure's material body can directly contact the ultra-high thermal conductivity metal electrodes, significantly improving the heat dissipation capacity of the quantum cascade laser waveguide structure. This significant improvement in heat dissipation allows the quantum cascade laser fabricated using this method to achieve a maximum output power several times higher than that of traditional dielectric-insulated lasers under continuous current operation at room temperature. Additionally, the fabrication process is relatively simple, yet the improvement in heat dissipation is extremely significant.

[0049] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0050] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for fabricating a high-power quantum cascade laser, characterized in that, include: A substrate, a buffer layer, a lower waveguide layer, an active layer, an upper waveguide layer, an upper cladding layer, and a capping layer are sequentially stacked along a first direction to form a stacked structure. The stacked structure includes a first part and a second part located on both sides of the first part. The active layer, the upper waveguide layer, the upper cladding layer, the capping layer, and the lower waveguide layer of a certain thickness corresponding to the first part are used to form a waveguide structure. The stacked structure is graphically represented by removing a portion of the second part of the thickness to form the waveguide structure. Specifically, before or after the waveguide structure is formed, a first mask layer with an implantation window is formed on the surface of the cap layer away from the upper cladding layer. The implantation window exposes the second portion, and ion implantation is performed through the implantation window to form an insulating region within a portion of the waveguide structure adjacent to the second portion and within a portion of the second portion away from the substrate. After forming the waveguide structure with the insulating region, a first electrode layer is formed on the insulating region and on the top surface of the waveguide structure. The step of forming the insulating region before forming the waveguide structure includes: A first mask layer is formed on the top surface of the stacked structure, and the implantation window exposes the second portion. Ion implantation is performed through the implantation window. Along the first direction, the implantation depth of the ion implantation is greater than the total thickness of the active layer, the upper waveguide layer, the upper cladding layer, and the capping layer, and the implantation depth of the ion implantation is less than the total thickness of the lower waveguide layer, the active layer, the upper waveguide layer, the upper cladding layer, and the capping layer. The step of forming the insulating region after forming the waveguide structure includes: forming a first mask layer on the top surface of the waveguide structure, the first mask layer exposing the remaining second portion and the side surface of the waveguide structure, the ion implantation including a first implantation process in a first implantation direction and a second implantation process in a second implantation direction, the angle between the first implantation direction and the second implantation direction is 90°, and the angle between the first implantation direction and the first direction is 45°, the angle between the second implantation direction and the first direction is 45°; The ion implantation energy is in the range of 50 keV to 500 keV, and the implantation dose is 2E12cm. -2 ~5E15cm -2 Within the range.

2. The method for fabricating a high-power quantum cascade laser according to claim 1, characterized in that, The implanted ions in the ion implantation step include at least one of hydrogen ions, helium ions, nitrogen ions, or argon ions.

3. The method for fabricating a high-power quantum cascade laser according to claim 1, characterized in that, The ion implantation direction is the first direction.

4. The method for fabricating a high-power quantum cascade laser according to claim 1, characterized in that, The thickness of the insulating region within the waveguide structure is in the range of 0.9 μm to 1.1 μm.

5. The method for fabricating a high-power quantum cascade laser according to claim 1, characterized in that, The step of patterning the stacked structure to form the waveguide structure before forming the insulating region includes: A second mask layer with an etching window is formed on the first portion, the etching window exposing the top surface of the second portion. The capping layer, the upper cladding layer, the upper waveguide layer, the active layer, and a portion of the thickness of the lower waveguide layer located in the second portion are removed through the etching window to form the waveguide structure.

6. The method for fabricating a high-power quantum cascade laser according to claim 5, characterized in that, The first mask layer is a dielectric layer, and the steps of forming the first mask layer after forming the waveguide structure include: The second mask layer is a photoresist layer. The second mask layer is removed, and an initial first mask layer is formed on the top surface of the remaining second part and the surface of the waveguide structure. Then the initial first mask layer on the side surface of the waveguide structure and the second part is removed, and the remaining initial first mask layer is used as the first mask layer. Alternatively, the second mask layer can be a dielectric layer, and the second mask layer can be used as the first mask layer.

7. The method for fabricating a high-power quantum cascade laser according to claim 1, characterized in that, The step of patterning the stacked structure to form the waveguide structure after forming the insulating region includes: Remove the first mask layer, form a photoresist layer on the top surface of the first portion, the photoresist layer having an etching window exposing the second portion, remove the capping layer, the upper cladding layer, the upper waveguide layer, the active layer and a portion of the thickness of the lower waveguide layer located in the second portion through the etching window to form the waveguide structure, and then remove the photoresist layer; Alternatively, a photoresist layer is formed on the top surface of the first mask layer, the photoresist layer having an etching window exposing the second portion, the capping layer, the upper cladding layer, the upper waveguide layer, the active layer and a portion of the thickness of the lower waveguide layer located in the second portion are removed through the etching window to form the waveguide structure, and then the photoresist layer and the first mask layer are removed.

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