Vertical cavity surface emitting laser with composite optical film layer

Abstract

The present invention provides a vertical cavity surface emitting laser having a composite optical film layer.SOLUTION: The vertical cavity surface emitting laser with a composite optical film layer includes a substrate, an electrode layer, a first reflective layer, a plurality of active light emitting layers, a plurality of second reflective layers, a plurality of first transparent conductive layers, and a composite optical film layer. Two opposite extending portions of the composite optical film layer define a light emitting hole. The refractive index of each optical film layer of the composite optical film layer gradually decreases from the optical film layer attached to the side wall surface to the outermost optical film layer. With such an arrangement, the composite optical film can prevent the spatial distribution of the laser from being in a high-order state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to vertical cavity surface emitting lasers, and more particularly to vertical cavity surface emitting lasers having composite optical film layers. [Background technology]

[0002] In conventional technology, vertical-cavity surface-emitting lasers typically utilize oxidation to form a highly resistive oxide layer in the upper Bragg reflector to limit the area through which current passes. However, forming a current-limiting oxide layer through oxidation is costly and results in a large hole diameter, which impacts light-emitting efficiency. In addition, the oxide layer formed through oxidation increases the lattice mismatch and thermal expansion coefficient difference between the oxide layer and the semiconductor material that constitutes the upper Bragg reflector, making it prone to defects (e.g., cracks) due to internal stress, further reducing yield, affecting light-emitting efficiency, and reducing device reliability.

[0003] Furthermore, if the spatial distribution of laser light from a vertical cavity surface emitting laser exhibits a higher order mode, the output power is high and the laser is therefore not suitable for communication-related technical fields that require low power output.

[0004] Therefore, how to improve the structural design to improve the light output efficiency of the vertical cavity surface emitting laser and overcome the above-mentioned defects has become one of the important problems that those skilled in the art are trying to solve. Summary of the Invention [Problem to be solved by the invention]

[0005] The technical problem that the present invention aims to solve is to provide a vertical cavity surface emitting laser with composite optical film layers in response to the shortcomings of the prior art. [Means for solving the problem]

[0006] The vertical cavity surface emitting laser with the composite optical film layer includes a substrate, at least one electrode layer, a first reflective layer, multiple active light emitting layers, multiple second reflective layers, multiple first transparent conductive layers, and the composite optical film layer. The substrate has a top surface and a bottom surface. The electrode layer is disposed on the bottom surface. The first reflective layer is disposed on the top surface. The first reflective layer includes a base portion and multiple reflective portions, the multiple reflective portions being arranged on the base portion at intervals, with a gap between each adjacent pair of reflective portions, and areas of the surface of the first reflective layer that do not have the multiple reflective portions define multiple exposed surfaces. The multiple active light emitting layers are positioned on the multiple reflective portions so as to correspond to each other. The multiple second reflective layers are positioned on the multiple active light emitting layers so as to correspond to each other. The multiple first transparent conductive layers are positioned on the multiple second reflective layers so as to correspond to each other. The composite optical film layer is formed by stacking multiple optical film layers, and includes multiple bottoms, multiple side sections, and multiple extensions, with both sides of each bottom connected to one end of each side section and each extension connected to the other end of each side section. The same side of each reflective section, each active light-emitting layer, and each second reflective layer defines a sidewall surface, with the side sections covering the sidewall surface and the bottom covering the exposed surface. Each extension is located between the first transparent conductive layer and the second reflective layer and corresponds to the first transparent conductive layer, defining a light output hole between two adjacent extensions. In the composite optical film layer, the refractive index of each optical film layer gradually decreases from the optical film layer attached to the sidewall surface to the outermost optical film layer.

[0007] According to one possible embodiment, the vertical cavity surface emitting laser with the composite optical film layer further includes a plurality of fillers, each of which is made of a conductive material or a dielectric material, and each of which has a bottom and two adjacent side portions that form a groove, and each of which includes a filler portion and a connecting portion that are connected to each other, the filler portion filling the groove, and both ends of the connecting portion respectively connecting to two adjacent first transparent conductive layers.

[0008] The present invention also provides a vertical cavity surface emitting laser having a composite optical film layer including a substrate, at least one electrode layer, a first reflective layer, a plurality of active light emitting layers, a plurality of second reflective layers, a plurality of first transparent conductive layers, and a composite optical film layer. The substrate has a top surface and a bottom surface. The electrode layer is disposed on the bottom surface. The first reflective layer is disposed on the top surface, and the first reflective layer includes a base portion and a plurality of reflective portions, the plurality of reflective portions being arranged on the base portion at intervals, with a gap between each adjacent pair of reflective portions, and areas of the surface of the first reflective layer not having the plurality of reflective portions define a plurality of exposed surfaces. The plurality of active light emitting layers are respectively positioned on the plurality of reflective portions in a corresponding manner. The plurality of second reflective layers are respectively positioned on the plurality of active light emitting layers in a corresponding manner. The plurality of first transparent conductive layers are respectively positioned on the plurality of second reflective layers in a corresponding manner. The composite optical film layer is formed by stacking multiple optical film layers, and the composite optical film layer includes multiple bottom portions, multiple side portions, and multiple extension portions, with both sides of each bottom portion connecting to one end of each side portion and each extension portion connecting to the other end of each side portion. The same side surfaces of each reflective portion, each active light-emitting layer, and each second reflective layer define sidewall surfaces, with the side portions covering the sidewall surfaces and the bottom portions covering the exposed surfaces. Each extension portion is located on the first transparent conductive layer and corresponds to the first transparent conductive layer to define a light output hole between two adjacent extension portions. In the composite optical film layer, the refractive index of each optical film layer gradually decreases from the optical film layer attached to the sidewall surfaces to the outermost optical film layer.

[0009] According to one possible embodiment, the vertical cavity surface emitting laser with the composite optical film layer further includes a plurality of fillers, each of which is made of a conductive material or a dielectric material, and the bottom and two adjacent side surfaces form a groove, and each filler fills the groove.

[0010] According to one possible embodiment, the composite optical film layer further includes a second transparent conductive layer attached to the sidewall surface.

[0011] According to one possible embodiment, the composite optical film layer further includes a second transparent conductive layer, which is the outermost optical film layer in the composite optical film layer.

[0012] According to one possible embodiment, the composite optical film layer further includes a second transparent conductive layer located between the optical film layer attached to the side wall surface and the outermost optical film layer in the composite optical film layer.

[0013] According to one possible implementation, there are multiple electrode layers, each positioned corresponding to a respective reflective portion, and the length of each electrode layer in the first direction is less than or equal to the length of each first transparent conductive layer in the first direction.

[0014] According to one possible embodiment, the first transparent conductive layer is a metal thin film or an indium tin oxide layer. [Effects of the Invention]

[0015] One of the beneficial effects of the present invention is that the vertical cavity surface emitting laser having the composite optical film layer provided by the present invention can effectively suppress the spatial distribution of higher-order modes of laser light from the vertical cavity surface emitting laser by providing the composite optical film layer, and can satisfy the requirement of a spatial distribution of single-mode laser light.

[0016] One of the beneficial effects of the present invention is that a vertical cavity surface emitting laser having a composite optical film layer provided by the present invention does not have a current limiting layer (especially an oxide layer formed by an oxidation treatment), which eliminates defects caused by the oxidation treatment and improves the quality of the vertical cavity surface emitting laser. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 2]1 is a cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 3] 1 is a partial cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 4] 1 is a partial cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 5] 1 is a partial cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 6] 1 is a cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 7] 1 is a partial cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 8] 1 is a partial cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 9] 1 is a partial cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 10] 1 is a cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. [Figure 11] 1 is a cross-sectional view of a vertical cavity surface emitting laser having a composite optical film layer according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] In order to better understand the features and technical contents of the present invention, reference is made to the following detailed description and drawings of the present invention, but the drawings provided are for reference and explanation only and are not intended to limit the present invention.

[0019] The following describes the implementation of the "vertical-cavity surface-emitting laser with composite optical film layers" disclosed by the present invention through specific examples, and those skilled in the art can understand the advantages and effects of the present invention from the disclosure of this specification. The present invention can be implemented or applied through other different specific examples, and various modifications and changes can be made to the details herein based on different perspectives and applications without departing from the concept of the present invention. Furthermore, it should be noted in advance that the accompanying drawings of the present invention are for simple schematic illustrations only and are not drawn to actual size. The technical content of the present invention will be described in more detail based on the following embodiments, but the disclosed content does not limit the protection scope of the present invention.

[0020] It should be understood that although the present specification may use terms such as "first" and "second" to describe various elements or signals, these elements or signals are not limited by these terms. These terms are primarily used to distinguish one element from another element or one signal from another signal. Furthermore, the term "or" used in the present specification may include any one or more combinations of the associated listed items, depending on the actual situation. [Example]

[0021] Referring to FIG. 1, FIG. 1 is a cross-sectional view of a vertical cavity surface-emitting laser Z1 having a composite optical film layer according to one embodiment of the present invention. The vertical cavity surface-emitting laser Z1 having a composite optical film layer 7 includes a substrate 1, an electrode layer 2, a first reflective layer 3, a plurality of active light-emitting layers 4, a plurality of second reflective layers 5, a plurality of first transparent conductive layers 6, and the composite optical film layer 7. The substrate 1 has a top surface 11 and a bottom surface 12. The electrode layer 2 is disposed on the bottom surface 12. The first reflective layer 3 is disposed on the top surface 11. The first reflective layer 3 includes a base portion 31 and a plurality of reflective portions 32. The reflective portions 32 are arranged on the base portion 31 at intervals, with a gap between each adjacent pair of reflective portions 32. Areas of the surface of the first reflective layer 3 that do not have the reflective portions 32 define a plurality of exposed surfaces 311. The active light-emitting layers 4 are disposed on the reflective portions 32, respectively, in a corresponding manner. The plurality of second reflective layers 5 are respectively positioned on the plurality of active light-emitting layers 4. The plurality of first transparent conductive layers 6 are respectively positioned on the plurality of second reflective layers 5. The composite optical film layer 7 is formed by stacking a plurality of optical film layers (the following description will be given using two or three optical film layers, but is not limited to this), and the composite optical film layer 7 includes a plurality of bottom portions 71, a plurality of side portions 72, and a plurality of extension portions 73, both sides of each bottom portion 71 are respectively connected to one end of each side portion 72, and each extension portion 73 is connected to the other end of each side portion 72. The same side of each reflective portion 32, each active light-emitting layer 4, and each second reflective layer 5 defines a sidewall surface S, with the side portions 72 covering the sidewall surface S and the bottom portions 71 covering the exposed surface 311, and each extending portion 73 being located between the first transparent conductive layer 6 and the second reflective layer 5 and corresponding to the first transparent conductive layer 6, defining a light exit hole O between two adjacent extending portions 73. In the composite optical film layer 7, the refractive index of each optical film layer gradually decreases from the optical film layer attached to the sidewall surface S to the outermost optical film layer.

[0022] The substrate 1 can be an insulating substrate or a semiconductor substrate. The insulating substrate can be, for example, sapphire, and the semiconductor substrate can be, for example, silicon, germanium, silicon carbide, or a III-V semiconductor. The III-V semiconductor can be, for example, gallium arsenide (GaAs), arsenic phosphide (InP), aluminum nitride (AIN), indium nitride (InN), or gallium nitride (GaN). In one embodiment, the electrode layer 2 is a metal or alloy and is disposed on the bottom surface 12 of the substrate 1. In one embodiment, the first reflective layer 3 and the second reflective layer 5 are distributed Bragg reflectors (DBRs) formed by alternately stacking two types of thin films with different refractive indexes, thereby allowing a beam having a predetermined wavelength to be reflected and resonated. In one embodiment, the materials of the first reflective layer 3 and the second reflective layer 5 can be doped III-V compound semiconductors. Furthermore, in one embodiment, the first reflective layer 3 and the second reflective layer 5 have different conductivity types. For example, the first reflective layer 3 is an N-type semiconductor layer, and the second reflective layer 5 is a P-type semiconductor layer. According to one embodiment, the first transparent conductive layer 6 is an indium tin oxide layer, which is optically transparent and electrically conductive and can be used as an electrical contact. In one embodiment, a separate electrode layer 2 (or electrical contact) may or may not be provided on the surface 61 of the first transparent conductive layer 6. Furthermore, according to one embodiment, the first transparent conductive layer 6 may also be a metal thin film, which, when it achieves a certain thinness, is optically transparent and can be used in a vertical cavity surface emitting laser.

[0023] According to one embodiment, the base portion 31 and the plurality of reflective portions 32 are formed by etching the first reflective layer 3, and the plurality of reflective portions 32 are arranged in an array on the base portion 31. For example, after the first reflective layer 3, the active light-emitting layer 4, and the second reflective layer 5 are disposed, the second reflective layer 5, the active light-emitting layer 4, and the first reflective layer 3 are etched in this order along the vertical direction D2, thereby forming the base portion 31 and the plurality of reflective portions 32 on the first reflective layer 3. However, the present invention is not limited thereto, and in one embodiment, the base portion 31 may be disposed first, and then a reflective layer may be disposed on the base portion 31, and then the plurality of reflective portions 32 may be formed by etching.

[0024] In one embodiment, the diameter d of the light exit hole O is 10 μm (micrometers) or less. That is, in one embodiment, the length of the mesa in the first direction D1 is slightly greater than 10 μm. The mesa includes a reflective portion 32, an active light-emitting layer 4, a second reflective layer 5, and a first transparent conductive layer 6. In one embodiment, with this structure, the diameter d of the light exit hole O is small, allowing the beam to be emitted in a nearly straight direction, resulting in a concentrated light beam.

[0025] 1, the composite optical film layer 7 includes two optical film layers, defined as a first optical film layer 7a and a second optical film layer 7b, respectively. The refractive index of the first optical film layer 7a is greater than that of the second optical film layer 7b. The composite optical film layer 7 is a composite film layer with a stepwise change in refractive index, such as an anti-reflective coating (AR film). In one embodiment, each optical film layer is made of the following materials: SiO / Ge / Al, or magnesium fluoride (MgF2). However, the present invention is not limited thereto. The refractive index of each optical film layer gradually decreases from the optical film layer attached to the side wall surface S to the outermost optical film layer. Therefore, by arranging in this manner, it is possible to effectively prevent the vertical cavity surface emitting laser from having a higher order laser light spatial distribution. Therefore, the vertical cavity surface emitting laser of the present invention can be applied to the field of communications, and can meet the requirement for a single mode laser light spatial distribution required in this technical field, while also having a relatively small output.

[0026] 2, which is a cross-sectional view of a vertical cavity surface-emitting laser Z2 having a composite optical film layer according to one embodiment of the present invention. In this embodiment, the vertical cavity surface-emitting laser Z2 having a composite optical film layer 7 further includes a plurality of fillers 8, each of which is made of a conductive material or a dielectric material. A bottom 71 and two adjacent side portions 72 form a groove V, and each filler 8 includes a filler portion 81 and a connecting portion 82 that are connected to each other. The filler portion 81 fills the groove V, and both ends of the connecting portion 82 are connected to two adjacent first transparent conductive layers 6.

[0027] In one embodiment, the filler 8 is a metal or alloy, such as copper metal, which has the effect of guiding current to the electrode layer 2. In addition, the filler 8 being a metal or alloy can further improve the heat dissipation effect of the vertical cavity surface emitting laser having the composite optical film layer 7.

[0028] According to one embodiment, the filler 8 is a dielectric material (eg, polyimide (PI)).

[0029] 3 to 5, which are local cross-sectional views of vertical cavity surface emitting lasers Z3 to Z5 having composite optical film layers according to embodiments of the present invention, respectively. According to these embodiments, the composite optical film layer 7 further includes a second transparent conductive layer 7c.

[0030] The second transparent conductive layer 7c may be located at the innermost position of the composite optical film layer, and may be attached to the side wall surface S, for example, as shown in Fig. 3. In the example shown in Fig. 3, the refractive index of the second transparent conductive layer 7c is greater than the refractive index of the first optical film layer 7a, which is greater than the refractive index of the second optical film layer 7b.

[0031] 4, the second transparent conductive layer 7c may be located between the optical film layer bonded to the side wall surface S and the outermost optical film layer in the composite optical film layer 7. In the embodiment shown in FIG. 4, the refractive index of the first optical film layer 7a is greater than the refractive index of the second transparent conductive layer 7c, which is greater than the refractive index of the second optical film layer 7b.

[0032] 5, the second transparent conductive layer 7c may be the outermost optical film layer in the composite optical film layer 7, in other words, the second transparent conductive layer 7c may be located on the outermost side of the composite optical film layer 7. According to the embodiment shown in FIG. 5, the refractive index of the first optical film layer 7a is greater than the refractive index of the second optical film layer 7b, and the refractive index of the second optical film layer 7b is greater than the refractive index of the second transparent conductive layer 7c.

[0033] In one embodiment, the material of the second transparent conductive layer 7c is the same as the material of the first transparent conductive layer 6 and is continuous with the first transparent conductive layer 6. For example, the first transparent conductive layer 6 and the second transparent conductive layer 7c are both indium tin oxide.

[0034] Referring to Figure 6, Figure 6 is a cross-sectional view of a vertical cavity surface-emitting laser Z6 having a composite optical film layer according to one embodiment of the present invention. This embodiment differs from the embodiment shown in Figure 1 in that the extension portion 73 of the composite optical film layer 7 is located on the first transparent conductive layer 6. This structure also effectively prevents the vertical cavity surface-emitting laser from having a higher-order mode spatial distribution of laser light, allowing the vertical cavity surface-emitting laser of the present invention to be applied to the field of communications, satisfying the requirement for a single-mode spatial distribution of laser light required in this technical field, while also having a relatively low output.

[0035] 7 to 9, which are local cross-sectional views of vertical cavity surface emitting lasers Z7 to Z9 having composite optical film layers according to embodiments of the present invention, respectively. According to these embodiments, the composite optical film layer 7 further includes a second transparent conductive layer 7c.

[0036] According to the embodiment shown in FIG. 7, the second transparent conductive layer 7c is bonded to the side wall surface S, and the refractive index of the second transparent conductive layer 7c is greater than the refractive index of the first optical film layer 7a, which is greater than the refractive index of the second optical film layer 7b.

[0037] 8, the second transparent conductive layer 7c is located between the optical film layer attached to the side wall surface S and the outermost optical film layer in the composite optical film layer 7, and as shown in Fig. 8, the second transparent conductive layer 7c is located between the first optical film layer 7a and the second optical film layer 7b. In this case, the refractive index of the first optical film layer 7a is greater than the refractive index of the second transparent conductive layer 7c, and the refractive index of the second transparent conductive layer 7c is greater than the refractive index of the second optical film layer 7b.

[0038] According to the embodiment shown in FIG. 9, the second transparent conductive layer 7c is located on the outermost side of the composite optical film layer 7, and the refractive index of the first optical film layer 7a is greater than that of the second optical film layer 7b, which is greater than that of the second transparent conductive layer 7c.

[0039] Referring to FIG. 10, FIG. 10 is a cross-sectional view of a vertical cavity surface-emitting laser Z10 having a composite optical film layer according to one embodiment of the present invention. The vertical cavity surface-emitting laser Z10 having the composite optical film layer 7 further includes a plurality of fillers 8, each of which is a conductive material or a dielectric material. The fillers 8 fill the grooves V. When the fillers 8 are metal or alloy, the heat dissipation effect of the vertical cavity surface-emitting laser can be improved, thereby improving product reliability. When the fillers 8 are a dielectric material, they are, for example, polyimide (PI).

[0040] Referring to FIG. 11, FIG. 11 is a cross-sectional view of a vertical cavity surface-emitting laser Z11 having a composite optical film layer according to one embodiment of the present invention. In this embodiment, there are multiple electrode layers 2, each positioned corresponding to a respective reflector 32. The length L1 of each electrode layer 2 in the first direction D1 is less than the length L2 of each first transparent conductive layer 6 in the first direction D1. The sidewall surface S formed on the same side of the reflector 32, active light-emitting layer 4, second reflector layer 5, and first transparent conductive layer 6 may have defects, which are unfavorable for current flow. Therefore, by designing the length L1 of the electrode layer 2 to be less than the length L2 of the first transparent conductive layer 6 (or less than the length of the mesa), the current flow is more easily concentrated in the electrode layer 2. [Industrial Applicability]

[0041] [Beneficial Effects of Examples] One of the beneficial effects of the present invention is that the vertical cavity surface emitting laser having the composite optical film layer provided by the present invention can effectively suppress the spatial distribution of higher-order modes of laser light from the vertical cavity surface emitting laser by providing the composite optical film layer, and can satisfy the requirement of a spatial distribution of single-mode laser light.

[0042] One of the beneficial effects of the present invention is that a vertical cavity surface emitting laser having a composite optical film layer provided by the present invention does not have a current limiting layer (especially an oxide layer formed by an oxidation treatment), which eliminates defects caused by the oxidation treatment and improves the quality of the vertical cavity surface emitting laser.

[0043] Furthermore, according to one embodiment of the present invention, the mesa size of the vertical cavity surface-emitting laser is optimized, and the diameter of the light exit hole is small, allowing the beam to exit from the light exit hole in a nearly straight direction, resulting in concentrated light rays and improving the light-emitting efficiency of the vertical cavity surface-emitting laser.

[0044] Furthermore, according to one embodiment of the present invention, the grooves of the vertical cavity surface-emitting laser are filled with a metal filler, which can improve the heat dissipation effect of the vertical cavity surface-emitting laser. Furthermore, the connection between the filler and the first transparent conductive layer can also align the current flow, further enhancing the effectiveness of the vertical cavity surface-emitting laser. Furthermore, according to one embodiment of the present invention, the grooves of the vertical cavity surface-emitting laser are filled with a dielectric material.

[0045] The above disclosure is merely a preferred embodiment of the present invention, and the scope of the claims of the present invention is not limited thereto. Therefore, all equivalent technical modifications made by utilizing the contents of the specification and drawings of the present invention are included in the scope of the claims of the present invention. [Explanation of symbols]

[0046] Z1 to Z11: Vertical-cavity surface-emitting lasers with composite optical film layers 1...Substrate 11...Top 12...Bottom 2...Electrode layer 3...First reflective layer 31...Base 311...Exposed surface 32…Reflector 4...Active light-emitting layer 5...Second reflective layer 6...First transparent conductive layer 61…Surface 7...Composite optical film layer 7a...First optical film layer 7b...Second optical film layer 7c...Second transparent conductive layer 71...Bottom 72...Side 73...Extension part 8...Filling body 81...Filling section 82...Connection part V…Groove S: Side wall d…pore diameter L1~L2...length O...Light exit hole D1...first direction D2...Second direction

Claims

1. a substrate having a top surface and a bottom surface; At least one electrode layer disposed on the bottom surface; a first reflective layer disposed on the top surface and including a base portion and a plurality of reflective portions; a plurality of active light-emitting layers respectively positioned on the plurality of reflecting portions; a plurality of second reflective layers respectively positioned on the plurality of active light-emitting layers; a plurality of first transparent conductive layers each positioned on the plurality of second reflective layers in a corresponding manner; a composite optical film layer formed by overlapping a plurality of optical film layers; the plurality of reflective portions are arranged on the base portion at intervals, and there is a gap between two adjacent reflective portions; and an area on the surface of the first reflective layer that does not have the plurality of reflective portions defines a plurality of exposed surfaces; the composite optical film layer comprises a plurality of bottom portions, a plurality of side portions, and a plurality of extension portions, each of the bottom portions being connected to one end of one of the side portions at both sides, each of the extension portions being connected to the other end of the side portions, the same side surfaces of each of the reflective portions, each of the active light-emitting layers, and each of the second reflective layers defining a sidewall surface, the side portions covering the sidewall surface, and the bottom portion covering the exposed surface, each of the extension portions being located between the first transparent conductive layer and the second reflective layer, and defining a light exit hole between two adjacent extension portions corresponding to the first transparent conductive layer, A vertical cavity surface emitting laser having a composite optical film layer, wherein the refractive index of each of the optical film layers gradually decreases from the optical film layer bonded to the side wall surface to the outermost optical film layer.

2. 2. The vertical cavity surface emitting laser having the composite optical film layer according to claim 1, further comprising a plurality of fillers, each of which is made of a conductive material or a dielectric material, the bottom and the two adjacent side portions thereof forming a groove, each of which includes a filling portion and a connecting portion which are connected to each other, the filling portion filling the groove, and both ends of the connecting portion respectively connected to two adjacent first transparent conductive layers.

3. The vertical cavity surface emitting laser having a composite optical film layer according to claim 1 , wherein the composite optical film layer further comprises a second transparent conductive layer attached to the side wall surface.

4. The vertical cavity surface emitting laser having a composite optical film layer according to claim 1 , wherein the composite optical film layer further comprises a second transparent conductive layer which is the outermost optical film layer in the composite optical film layer.

5. 2. The vertical cavity surface emitting laser having a composite optical film layer according to claim 1, wherein the composite optical film layer further comprises a second transparent conductive layer positioned between the optical film layer bonded to the side wall surface and the outermost optical film layer in the composite optical film layer.

6. a substrate having a top surface and a bottom surface; At least one electrode layer disposed on the bottom surface; a first reflective layer disposed on the top surface and including a base portion and a plurality of reflective portions; a plurality of active light-emitting layers respectively positioned on the plurality of reflecting portions; a plurality of second reflective layers respectively positioned on the plurality of active light-emitting layers; a plurality of first transparent conductive layers each positioned on the plurality of second reflective layers in a corresponding manner; a composite optical film layer formed by overlapping a plurality of optical film layers; the plurality of reflective portions are arranged on the base portion at intervals, with a gap between two adjacent reflective portions, and an area on the surface of the first reflective layer that does not have the plurality of reflective portions defines a plurality of exposed surfaces; the composite optical film layer includes a plurality of bottom portions, a plurality of side portions, and a plurality of extension portions, each of the bottom portions being connected to one end of one of the side portions at both sides, each of the extension portions being connected to the other end of the side portions, the same side surfaces of each of the reflective portions, each of the active light-emitting layers, and each of the second reflective layers defining a sidewall surface, the side portions covering the sidewall surface, and the bottom portion covering the exposed surface, each of the extension portions being located on the first transparent conductive layer, corresponding to the first transparent conductive layer, defining a light exit hole between two adjacent extension portions; A vertical cavity surface emitting laser having a composite optical film layer, wherein the refractive index of each of the optical film layers gradually decreases from the optical film layer bonded to the side wall surface to the outermost optical film layer.

7. The vertical cavity surface emitting laser having a composite optical film layer according to claim 6 , wherein the composite optical film layer further comprises a second transparent conductive layer attached to the side wall surface.

8. 7. The vertical cavity surface emitting laser having a composite optical film layer according to claim 6, wherein the composite optical film layer further includes a second transparent conductive layer positioned between the optical film layer bonded to the side wall surface and the outermost optical film layer in the composite optical film layer.

9. 7. The vertical cavity surface emitting laser having a composite optical film layer according to claim 6, wherein the composite optical film layer further comprises a second transparent conductive layer which is the outermost optical film layer in the composite optical film layer.

10. 7. The vertical cavity surface emitting laser having the composite optical film layer according to claim 6, further comprising a plurality of fillers, each of which is a conductive material or a dielectric material, the bottom and the two adjacent side portions forming a groove, and each of which is filled into the groove.

11. 11. A vertical cavity surface emitting laser having a composite optical film layer according to claim 1, wherein the electrode layers are plural, each of which is positioned corresponding to each of the reflecting portions, and the length of each of the electrode layers in the first direction is equal to or less than the length of each of the first transparent conductive layers in the first direction.

12. 11. The vertical cavity surface emitting laser having composite optical film layers according to claim 1, wherein the first transparent conductive layer is a metal thin film or an indium tin oxide layer.

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