An oxidation island anti-resonant waveguide vertical cavity surface emitting laser, a preparation method and applications thereof

Abstract

The application discloses an oxidation island anti-resonant waveguide vertical cavity surface emitting laser, a preparation method and application thereof, and relates to the technical field of semiconductors. The preparation method of the existing base transverse mode vertical cavity surface emitting laser for ensuring output power is complex, the light output power is small, the cost is high, the precision requirement is high, and the base transverse mode vertical cavity surface emitting laser is not conducive to wide application. The laser comprises, from top to bottom, a first electrode, a P-type Bragg reflector, a first oxidation layer, a first active region, a tunnel junction, a second oxidation layer, a second active region, an N-type Bragg reflector, a substrate and a second electrode. Oxidation islands are arranged in the light transmission apertures of the second pair and the ninth pair of p-DBR of the P-type Bragg reflector, and the width of the oxidation island of the first electrode close to the other oxidation island is greater. The oxidation islands are used for anti-waveguide high-order mode limiting. The base transverse mode vertical cavity surface emitting laser has the advantages of large light output power, simple preparation, low cost, low precision requirement and wide application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to an oxide-island anti-resonant waveguide vertical cavity surface emitting laser, a preparation method and applications thereof. BACKGROUND

[0002] Since the vertical cavity surface emitting laser (VCSEL) was invented in 1978, it has experienced rapid development. It has many advantages that traditional edge-emitting lasers cannot match, such as small size, low threshold current, high conversion efficiency, good single longitudinal mode, circular output spot, on-chip testing, and easy integration into large-area arrays. Based on these advantages, VCSELs have rapidly occupied the market of semiconductor lasers in recent years and play an important role in optical communication, sensing, storage and other fields.

[0003] In the laser resonant cavity, the stable distribution of the light field in a certain cross section perpendicular to the propagation direction is defined as the transverse mode. The fundamental transverse mode is approximately a Gaussian beam, which has higher spectral purity, coherence, narrower linewidth, and better wavelength stability, and is not affected by dispersion in long-distance optical information transmission. Ideally, only the fundamental transverse mode can satisfy the resonance condition for lasing, but in VCSELs, due to the large size of the transverse resonant cavity, and in actual situations, the reflecting surface and the active region are not ideal planes, and the distribution of injected carriers is uneven and the active region has a thermal lens effect, making it difficult for the device to achieve fundamental transverse mode output.

[0004] For VCSEL devices, multi-transverse mode operation and small output power are a major problem. Different transverse mode distributions are different, and there is overlap between them, with strong competition, which seriously affects the switching and transmission characteristics of the device. In the field of optical communication for data transmission, the optical signal generated by the multi-mode VCSEL is affected by spectral dispersion and mode dispersion, limiting the transmission distance, and the high-order mode absorbs most of the current, affecting the injection efficiency of the fundamental transverse mode, reducing the relaxation oscillation frequency, and thus limiting the intrinsic bandwidth.

[0005] In addition, in the field of optical sensing and optical interconnection, the coherence and wavelength stability of multi-transverse mode are not as good as those of the fundamental transverse mode, which affects the accuracy of sensing and interconnection. On the other hand, the output optical power directly affects the transmission distance of the optical communication link, but the output power of the fundamental transverse mode is usually small, making it difficult to overcome the inherent loss and achieve long-distance transmission in the field of optical communication, and higher output power is needed to improve the transmission distance of the communication link.

[0006] At present, in the case of taking into account the fundamental transverse mode and high power output, several mainstream methods on the market are: 1. By etching photonic crystal structure on the surface of DBR, using the refractive index difference between photonic crystal pattern and defect area to change the mode distribution. However, the high aspect ratio air hole of this structure is difficult to prepare, and the etching cavity will also cause the increase of optical loss threshold current, which limits the maximum output power of the device; 2. By etching surface relief pattern on the surface of the high-order mode lasing area of the upper DBR, increasing the high-order mode mirror loss to realize fundamental transverse mode lasing. However, the high-order mode loss area of this structure requires very high etching precision, and any deviation will affect the mode selection effect; 3. By increasing the limiting layer of the original resonant cavity, using the relatively large divergence angle of high-order mode to better scatter it to realize fundamental transverse mode lasing. However, this structure requires high epitaxial technology, involves complex process, and is highly sensitive to dislocation and mechanical disturbance, which has certain preparation difficulty; 4. By preparing high-contrast grating instead of traditional DBR as reflector, designing and optimizing the grating structure through the selection characteristics of the grating to suppress high-order mode and realize fundamental transverse mode lasing under high power. However, this structure requires special designed epitaxial wafer, and etching sub-wavelength grating requires high process precision; 5. By reflecting the fundamental mode back to the active area through the anti-resonant reflecting optical waveguide, introducing sufficient gain in the core layer with low refractive index to compensate for the leakage of fundamental transverse mode to high refractive index cladding, while the high-order mode has a large edge radiation effect and leaks out, thereby realizing fundamental transverse mode lasing. However, the preparation of this structure requires secondary epitaxial technology, the process is relatively complex, and it is also highly sensitive to dislocation and mechanical disturbance.

[0007] Based on the above several design methods of fundamental transverse mode VCSEL under the premise of ensuring output power, on the one hand, the preparation steps are relatively numerous, and some structures require special epitaxial wafers, which has high manufacturing cost, on the other hand, the process precision of structure design and manufacturing is high, and any deviation will affect the output mode. In addition, these complex structure designs increase the additional optical loss and internal resistance, resulting in an increase in threshold current, usually more than 1mA, and generally the high-order mode will be lased before the thermal rollover current of the fundamental transverse mode under high injection current. At the same time, the existing single-mode output VCSEL structure design is basically based on single active area, and the output power of the fundamental transverse mode is difficult to exceed 10mW. SUMMARY

[0008] The present application aims to solve the problems of the prior art, such as complex preparation method, low light output power, high cost, high precision requirement and the like of the base transverse mode vertical cavity surface emitting laser for ensuring output power, and the present application realizes the mode selection under a large aperture by introducing two width-gradually-changing oxidation islands in the upper P-type DBR in the light transmission aperture to change the carrier distribution and the leakage loss of different modes, thereby changing the light distribution of different modes and increasing the difference of threshold current of different modes, and the width-gradually-changing oxidation islands are prepared by using the different oxidation rates of AlGaAs with different Al components under the plane oxidation technology; and a tunnel junction structure is used to cascade double active regions to improve the output power of the base transverse mode, thereby obtaining a multi-oxidation island anti-resonant waveguide double-junction 1064nm high-power single-mode output vertical cavity surface emitting laser, which can meet the application of various single-mode high-power light sources, such as being used as a light source for long-distance free space optical communication and optical interconnection.

[0009] In order to achieve the above-mentioned purpose, the present application specifically adopts the following technical scheme:

[0010] An oxidation island anti-resonant waveguide vertical cavity surface emitting laser, the laser comprises, from top to bottom, a first electrode, a P-type Bragg reflector, a first oxidation layer, a first active region, a tunnel junction, a second oxidation layer, a second active region, an N-type Bragg reflector, a substrate and a second electrode, oxidation islands are arranged in the light transmission apertures of the second pair and the ninth pair of p-DBR of the P-type Bragg reflector, and the width of the oxidation island close to the first electrode is greater than that of the other oxidation island, and the oxidation islands are used for anti-waveguide high-order mode restriction.

[0011] As an improvement, the P-type Bragg reflector comprises 18-25 pairs of p-type AlGaAs layers with high Al component, and the doping concentration is 1.8*10 18 cm -3 ~2.2*10 18 cm -3 .

[0012] As an improvement, oxidation islands are arranged in the light transmission apertures of the AlGaAs layers of the second pair and the ninth pair of p-DBR, and each of the oxidation islands is formed by plane oxidation of the AlGaAs layer in the light transmission aperture.

[0013] As an improvement, the light transmission aperture is 8-12μm.

[0014] As an improvement, the N-type Bragg reflector comprises 34-38 pairs of n-type doped AlGaAs layers, and the doping concentration is 1.5*10 18 cm -3 ~2*10 18 cm -3 .

[0015] As an improvement, the substrate is a GaAs substrate.

[0016] As an improvement, the material of the first electrode and the second electrode is any one of gold, copper, graphite, silver or tin.

[0017] As an improvement, the interval between the first active region and the second active region is 1.5 lambda, and the width of the tunnel junction is 4-11 nm.

[0018] The application also provides a preparation method of the oxidation island anti-resonant waveguide vertical cavity surface emitting laser.

[0019] S1, sequentially epitaxially growing an N-type Bragg reflector, a second active region, a tunnel junction, a first active region, an oxidation layer and a P-type Bragg reflector on a substrate, and setting width-graduated oxidation islands in the second pair and the ninth pair of p-DBR light transmission apertures of the P-type Bragg reflector by plane oxidation to obtain a first preform.

[0020] S2, setting a first electrode on the upper part of the N-type Bragg reflector of the first preform and setting a second electrode on the lower part of the N-type Bragg reflector of the first preform to complete the preparation of the laser.

[0021] The application also provides an application of the oxidation island anti-resonant waveguide vertical cavity surface emitting laser in a semiconductor laser.

[0022] Compared with the prior art, the application has the following advantages:

[0023] 1. The oxidation island anti-resonant waveguide vertical cavity surface emitting laser increases the light output power by setting two active regions in the structure, sets two width-graduated oxidation islands in the p-DBR light transmission apertures for anti-waveguide high-order mode restriction to form an anti-resonant waveguide, effectively changes the distribution of carriers and light modes, and can solve the problems of the prior art, such as complex preparation method, small light output power, high cost, high precision requirement and difficulty in wide application, of the base transverse mode vertical cavity surface emitting laser for ensuring the output power.

[0024] 2. The preparation method of the oxidation island anti-resonant waveguide vertical cavity surface emitting laser is simple, has low cost and low precision requirement, and is convenient for wide application.

[0025] 3. The application of the oxidation island anti-resonant waveguide vertical cavity surface emitting laser has a wide application field. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1A structure schematic diagram of an oxidation island anti-resonance waveguide vertical cavity surface emitting laser of the present application.

[0027] Figure 2 Four common transverse mode I-P curve diagrams of the oxidation island anti-waveguide VCSEL of the present application.

[0028] Figure 3 LIV curve diagram of the base transverse mode LP01 of the oxidation island anti-waveguide VCSEL of the present application.

[0029] BRIEF DESCRIPTION OF DRAWINGS: 1-first electrode; 2-P-type Bragg reflector; 3-first oxidation layer; 4-first active region; 5-tunnel junction; 6-second oxidation layer; 7-second active region; 8-N-type Bragg reflector; 9-substrate; 10-second electrode.

[0030] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments of the present application.

[0031] Therefore, the following detailed description of the embodiments of the present application provided is not intended to limit the scope of the claimed application, but only to represent selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. DETAILED DESCRIPTION

[0032] Please refer to Figure 1 An oxidation island anti-resonance waveguide vertical cavity surface emitting laser, the laser comprises, from top to bottom, a first electrode 1, a P-type Bragg reflector 2, a first oxidation layer 3, a first active region 4, a tunnel junction 5, a second oxidation layer 6, a second active region 7, an N-type Bragg reflector 8, a substrate 9, and a second electrode 10. Oxidation islands are arranged in the second pair and the ninth pair of p-DBR clear apertures of the P-type Bragg reflector 2, and the width of the oxidation island close to the first electrode 1 is greater than that of the other oxidation island. The oxidation islands are used for anti-waveguide high-order mode limitation.

[0033] It can be understood that the present application relates to an oxidation island anti-resonance waveguide vertical cavity surface emitting laser. By arranging two active regions in the structure, the light output power is increased. By arranging two width-gradually-changing oxidation islands in the p-DBR clear aperture, anti-waveguide high-order mode limitation is achieved, thereby forming an anti-resonance waveguide. The distribution of carriers and light modes is effectively changed, and the problems of the prior art, such as complex preparation method of base transverse mode vertical cavity surface emitting laser for ensuring output power, small light output power, high cost, high precision requirement, and being not conducive to wide application, are solved.

[0034] Further, by adding high-doped tunnel junctions in the structure, two active regions are connected in series in the same resonant cavity, thereby achieving multiplication of photon number and quantum efficiency, and thus obtaining greater gain.

[0035] Further, without increasing the chip area, the light output power of the multi-junction cascade VCSEL is multiplied relative to the output power of the single-junction VCSEL of the same aperture, not only obtaining a higher power density, but also greatly improving the power conversion efficiency (PCE) of the VCSEL device. In addition, the increase in gain can reduce the operating current of the multi-junction VCSEL, thereby reducing the power consumption and cost of the driving circuit, and also achieving a compromise between voltage and current to improve the compatibility of the driving circuit.

[0036] By optimizing the spacing of the two active regions, the width of the tunnel junction, placing two p-type high-component Al AlGaAs layers, and forming two insulating oxide layers: Al2O3 oxide layers through planar oxidation, the first oxide layer is located between the high and low refractive index materials of the first pair of p-DBR, and the second oxide layer is located between the two active regions, all the oxidation confinement layers and the tunnel junction are located at the nodes of the standing wave through precise calculation and control of the optical field to reduce the current crowding effect at the edge of the oxide layer and the free carrier absorption loss caused by the heavily doped tunnel junction. Controlling the aperture diameter of the oxidation can limit the carriers and the transverse optical field, ensuring high output power.

[0037] In addition to the oxidation layer that limits the carriers and the optical field, by optimizing the structure to place a high-component Al p-type AlGaAs layer between the high and low refractive index materials of the second pair of p-DBR, and a high-component Al p-type AlGaAs layer between the high and low refractive index materials of the ninth pair of p-DBR, and using the phenomenon that the oxidation rate of AlGaAs materials with different Al components is different, two Al2O3 oxidation islands with gradually changing width located in the middle of the light aperture are generated by oxidation. Since the refractive index of Al2O3 is lower than that of AlGaAs, a counter-waveguide structure is formed, introducing a strong transverse mode selection mechanism based on the leaky mode, and realizing the output of the fundamental transverse mode under the condition of a large aperture.

[0038] The influence of the oxidation island with good insulation on the carrier and the light field distribution is used to increase the radiation loss difference between the base transverse mode and the high-order mode, thereby increasing the difference of the threshold current of the mode, so that the high-order mode reaches the threshold current before and after the base transverse mode reaches the thermal rollover current. Meanwhile, because the refractive index difference between the core and the cladding of the anti-waveguide structure formed by the oxidation island is small, the number of transverse modes of lasing is small, so that single-mode operation can be ensured under a large light aperture, and high-power output is maintained. In the light field design, by accurately calculating and controlling the thickness of the material, all the active regions are located at the antinodes of the light field standing wave, and all the oxidation layers (limiting layers and oxidation islands) are located at the nodes of the light field standing wave, so as to reduce the current crowding effect and the absorption loss of the device.

[0039] In some embodiments of the present application, the P-type Bragg reflector includes 18-25 pairs of p-type high Al component AlGaAs layers, and the doping concentration is 1.8*10 18 cm -3 ~2.2*10 18 cm -3 .

[0040] Specifically, the P-type Bragg reflector preferably includes 20 pairs of p-type high Al component AlGaAs layers, and the doping concentration is 2*10 18 cm -3 .

[0041] In some embodiments of the present application, oxidation islands are arranged in the light apertures of the AlGaAs layers of the second pair and the ninth pair of p-DBRs, respectively, and each of the oxidation islands is formed by planar oxidation of the AlGaAs layer in the light aperture.

[0042] In some embodiments of the present application, the Al component of the AlGaAs layers of the second pair and the ninth pair of p-DBRs is higher than that of the AlGaAs layers of other p-DBRs.

[0043] In some embodiments of the present application, the width of the oxidation island close to the first electrode is 9.5-10 microns, and the width of the other oxidation island is 7.5-8.5 microns.

[0044] In some embodiments of the present application, the oxidation islands are prepared by planar oxidation of the portions of the AlGaAs layers of the second pair and the ninth pair of p-DBRs located in the middle of the light apertures to become Al2O3, thereby obtaining Al2O3 oxidation islands, and the width of the oxidation island close to the first electrode is greater than that of the oxidation island away from the first electrode, thereby forming an anti-waveguide structure, introducing a strong transverse mode selection mechanism based on a leaky mode, and realizing base transverse mode output under a large aperture.

[0045] In some embodiments of the present application, the light transmission aperture is 8-12 μm. Specifically, the light transmission aperture is preferably 10 μm.

[0046] In some embodiments of the present application, the N-type Bragg reflector comprises 34-38 pairs of n-type doped AlGaAs layers, with a doping concentration of 1.5×10 18 cm -3 ~2×10 18 cm -3 . Specifically, the N-type Bragg reflector comprises 36 pairs of n-type doped AlGaAs layers, with a doping concentration of 1.8×10 18 cm -3 .

[0047] In some embodiments of the present application, the substrate is a GaAs substrate.

[0048] In some embodiments of the present application, the material of the first electrode and the second electrode is any one of gold, copper, graphite, silver or tin. Specifically, the material of the first electrode and the second electrode is gold.

[0049] In some embodiments of the present application, the distance between the first active region and the second active region is 1.5λ, and the width of the tunnel junction is 4-11 nm. The width of the tunnel junction is preferably 8 nm.

[0050] The present application also provides a preparation method of the above-mentioned oxide-island anti-resonant waveguide vertical cavity surface emitting laser, comprising the following steps:

[0051] S1. Sequentially epitaxially growing, on a substrate, an N-type Bragg reflector, a second active region, a second oxide layer, a tunnel junction, a first active region, a first oxide layer, and a P-type Bragg reflector, and setting, in the light transmission apertures of the second pair and the ninth pair of p-DBRs of the P-type Bragg reflector, width-gradually-changing oxide islands by planar oxidation, to obtain a first preform;

[0052] S2. Setting a first electrode on the upper part of the N-type Bragg reflector of the first preform and a second electrode on the lower part of the N-type Bragg reflector of the first preform, to complete the preparation of the laser.

[0053] It can be understood that the preparation method of the present application is simple, has low cost, and has low precision requirement, and is convenient for wide application. The prepared VCSEL has greatly improved fundamental transverse mode output power and good performance.

[0054] The present application also provides the application of the above-mentioned oxide-island anti-resonant waveguide vertical cavity surface emitting laser in semiconductor lasers. The application field is wide.

[0055] Example 1

[0056] An oxide island anti-resonant waveguide vertical cavity surface emitting laser 1, the laser comprises from top to bottom, a first electrode, a P-type Bragg reflector, a first oxide layer, a first active region, a tunnel junction, a second oxide layer, a second active region, an N-type Bragg reflector, a substrate, a second electrode, a second pair and a ninth pair of p-DBR in the clear aperture of the P-type Bragg reflector are provided with width-graduated oxide islands, the oxide islands are used for anti-waveguide high-order mode restriction. The P-type Bragg reflector comprises 18-25 pairs of p-type high-component Al AlGaAs layers, the doping concentration is 1.8×10 18 cm -3 ~2.2×10 18 cm -3 . The clear aperture of the AlGaAs layers of the second pair and the ninth pair of p-DBR is provided with width-graduated oxide islands, the oxide islands are formed by planar oxidation of the AlGaAs layers in the clear aperture. The clear aperture is 8-12 μm. The N-type Bragg reflector comprises 34-38 pairs of n-type doped AlGaAs layers, the doping concentration is 1.5×10 18 cm -3 ~2×10 18 cm -3 .

[0057] Test Example 1. Performance verification of the vertical cavity surface emitting laser of the application

[0058] 1.1 Test design

[0059] The multi-oxide island anti-resonant waveguide vertical cavity surface emitting laser 1 involved in Example 1 is selected, and four common transverse mode I-P curve analysis and oxide island anti-waveguide VCSEL base transverse mode LP01 LIV curve analysis are carried out, and the analysis results are shown in Figure 2 and Figure 3 .

[0060] 1.2 Result analysis

[0061] Referring to the I-P curve of Figure 2 , the multi-oxide island anti-resonant waveguide vertical cavity surface emitting laser 1 of Example 1 of the application can obviously determine the threshold current difference by using different modes within a working current of 12 mA, and the vertical cavity surface emitting laser 1 of Example 1 of the application can only emit LP01 base transverse mode, so the vertical cavity surface emitting laser of the application can meet the base transverse mode.

[0062] Referring to the LIV curve shown in Figure 3 , the multi-oxide island anti-resonant waveguide vertical cavity surface emitting laser 1 of Example 1 of the application can reach a Power MAXThe base transverse mode output power, the electrical performance, I th The threshold current is 0.72mA, the slope efficiency is 2.4 W / A, the V0 opening voltage is 2.2V, and the PCE MAX The maximum photoelectric conversion efficiency reaches 58.45 %. It can be seen that the vertical cavity surface emitting laser in the base transverse mode can also realize large power output at the same time, and has strong superiority.

[0063] In summary, the vertical cavity surface emitting laser with oxidation island anti-resonant waveguide involved in the application utilizes a tunnel junction to connect two active regions in series, greatly improves the base transverse mode light output power and the PCE of the device; and the anti-waveguide structure of the oxidation island is designed in a large through-hole aperture, the threshold current difference of different modes can be increased, so that the VCSEL mainly emits in the base transverse mode. Compared with the previous single-mode high-power VCSEL structure, the output power of the base transverse mode is greatly improved, the preparation process is simple, and the cost is low.

[0064] The above embodiment is only one embodiment of the application, which is described in detail, but it cannot be understood as a limitation on the scope of the patent of the application. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which all belong to the protection scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. An oxidized island anti-resonant waveguide vertical cavity surface emitting laser, comprising: The laser comprises, from top to bottom, a first electrode, a P-type Bragg reflector, a first oxide layer, a first active region, a tunnel junction, a second oxide layer, a second active region, an N-type Bragg reflector, a substrate, and a second electrode, wherein the second pair and the ninth pair of p-DBRs of the P-type Bragg reflector are respectively provided with an oxide island in the light transmission aperture, and the width of the oxide island close to the first electrode is greater than that of the other oxide island, and the oxide islands are used for anti-waveguide high-order mode confinement.

2. The oxide-apart antiresonant waveguide vertical cavity surface emitting laser of claim 1, wherein, The P-type Bragg mirror includes 18-25 pairs of p-type high composition Al of AlGaAs layers, with a doping concentration of 1.8 x 10 18 cm -3 ~2.2 x 10 18 cm -3 .

3. The oxide-apart antiresonant waveguide vertical cavity surface emitting laser of claim 2, wherein, The second pair and the ninth pair of p-DBRs of the AlGaAs layer are respectively provided with an oxide island in the light transmission aperture, and each of the oxide islands is formed by planar oxidation of the AlGaAs layer in the light transmission aperture.

4. The oxide-apartant antiresonant waveguide vertical cavity surface emitting laser of claim 3, wherein, The light transmission aperture is 8-12 μm.

5. The oxide-apartant antiresonant waveguide vertical cavity surface emitting laser of claim 1, wherein, The N-type Bragg mirror includes 34-38 pairs of n-type doped AlGaAs layers with a doping concentration of 1.5 x 1018cm"2 18 cm -3 ~2 x 1018cm"2 18 cm -3 .

6. The oxide-apartant antiresonant waveguide vertical cavity surface emitting laser of claim 1, wherein, The substrate is a GaAs substrate.

7. The oxide-apartant antiresonant waveguide vertical cavity surface emitting laser of claim 1, wherein, The first electrode and the second electrode are made of any one of gold, copper, graphite, silver, and tin.

8. The oxide-apartant antiresonant waveguide vertical cavity surface emitting laser of claim 1, wherein, The distance between the first active region and the second active region is 1.5λ, and the width of the tunnel junction is 4-11 nm.

9. A method of fabricating an Oxide Island Anti-Resonant Waveguide Vertical Cavity Surface Emitting Laser according to any of claims 1 to 8, characterized in that, The method comprises the following steps: S1. sequentially epitaxially growing, on a substrate, an N-type Bragg reflector, a second active region, a second oxide layer, a tunnel junction, a first active region, a first oxide layer, and a P-type Bragg reflector, and setting, by planar oxidation, oxide islands with gradually changing width in the light transmission apertures of the second pair and the ninth pair of p-DBRs of the P-type Bragg reflector to obtain a first preform; S2. setting a first electrode on the upper part of the N-type Bragg reflector of the first preform and a second electrode on the lower part of the N-type Bragg reflector of the first preform to complete the fabrication of the laser.

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