High-refractive-index extended cavity vertical cavity surface emitting laser, preparation method and application thereof

Abstract

The application discloses a high-refractive-index extended-cavity vertical-cavity surface-emitting laser, a preparation method and application thereof, and relates to the technical field of semiconductors. The application solves the problems of a large line width of an existing vertical-cavity surface-emitting laser and difficulty in controlling a narrow line width in the prior art. The laser comprises, from top to bottom, a top electrode, a p-type Bragg mirror group, an oxidation layer, an active region, an n-type extension layer, an n-type Bragg mirror group, a substrate and a bottom electrode, wherein the n-type extension layer is Al y Ga 1‑ y As, and y is 0.1-0.9. By arranging the n-type extension layer and setting the n-type extension layer to a specific material, resistance and free carrier absorption in the extension layer are inhibited, the effective cavity length of the laser is effectively increased, the resonant cavity length is increased, the output power is increased, the line width enhancement factor alpha is reduced, and the spectral line width is narrowed.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a high-refractive-index extended-cavity vertical-cavity surface-emitting laser, its fabrication method, and its applications. Background Technology

[0002] Since the successful firing of the first semiconductor laser in 1962, its advantages, including small size, high efficiency, excellent beam quality, and low cost, have made semiconductor lasers play a crucial role in today's booming technological fields. Vertical-cavity surface-emitting lasers (VCSELs), as an important member of the semiconductor laser family, offer advantages over edge-emitting lasers, such as small size, low threshold current, high conversion efficiency, good longitudinal mode uniformity, a circular output spot, on-chip testing capabilities, and easy integration into large-area arrays. These advantages have led to their widespread application in numerous technological fields, including optical communication systems, 3D sensing, optical interconnects, optical computing, lidar, and laser printers. In particular, with the continuous development of technologies such as atomic gyroscopes and optically pumped magnetometers, narrow-linewidth, high-beam-quality VCSELs are increasingly becoming a focus of attention.

[0003] Any frequency noise present in a laser will be converted into amplitude noise; therefore, narrow-linewidth VCSELs typically require a linewidth of less than 100MHz to reduce system noise. However, the inherent short photon lifetime in a conventional VCSEL cavity makes achieving a linewidth of less than 100MHz a challenge. Currently, mainstream narrow-linewidth VCSEL lasers on the market primarily achieve this by increasing the length of the external cavity. On the one hand, this increases the size of the laser system, reduces its integration density, and makes the optical path system more complex. On the other hand, the external cavity system causes the VCSEL to generate multi-mode lasing, and changes in current often cause mode switching, requiring precise control of the external cavity optical feedback intensity to avoid spectral linewidth drift. Furthermore, the external cavity system is complex to manufacture, and the external optical frequency selection elements require high stability in coupling the optical path and operating environment, often necessitating secondary epitaxy. This increases the operational difficulty and cost of external cavity VCSEL lasers. Due to their short effective cavity length (typically about one wavelength), existing VCSELs struggle to achieve linewidths below 20MHz.

[0004] It is evident that existing vertical cavity surface-emitting lasers have a large linewidth, and the methods for addressing this large linewidth have many shortcomings. Summary of the Invention

[0005] This invention aims to solve the problems of large linewidth in existing vertical-cavity surface-emitting lasers and the difficulty in controlling narrow linewidth in current technologies. This invention can effectively increase the effective cavity length of the laser and sets the n-type extension layer as Al. y Ga 1-yThe use of As material suppresses resistance and free carrier absorption in the extended layer, thereby narrowing the spectral linewidth.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0007] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser (VCSEL) comprises, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode. The n-type extended layer is Al. y Ga 1-y As, where y is 0.1 to 0.9.

[0008] Optionally, the thickness of the n-type extended layer is 0.8–2.5 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 ~2.2×10 18 cm -3 .

[0009] Optionally, the p-type Bragg mirror group consists of 20 to 25 pairs of p-type Al. x Ga 1-x As / Al y Ga 1-y As, where x is 0.88 to 0.92 and y is 0.1 to 0.16.

[0010] Optionally, the p-type Al x Ga 1-x As / Al y Ga 1-y As doping concentration 2×10 18 cm -3 ~3×

[0011] 10 18 cm -3 .

[0012] Optionally, the n-type Bragg mirror group consists of 32 to 40 pairs of n-type Al. x Ga 1-x As / Al y Ga 1-y As, where x is 0.88 to 0.92 and y is 0.1 to 0.16.

[0013] Optionally, the n-type Al x Ga 1-x As / Al y Ga 1-y The As doping concentration is 1.8 × 10⁻⁶. 18 cm -3 ~2.2×10 18 cm-3 .

[0014] Optionally, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 1.8 × 10⁻⁶ 18 cm -3 ~2.2×10 18 cm -3 The thickness is 20-30 nm.

[0015] Optionally, the oxide layer is provided with several oxide pores with a diameter of 3.0 to 4.0 μm.

[0016] This invention also provides a method for fabricating a high-refractive-index extended-cavity vertical-cavity surface-emitting laser, comprising the following steps:

[0017] S1. On the substrate, an n-type Bragg mirror assembly, an n-type extended layer, an active region, an oxide layer, and a p-type Bragg mirror assembly are sequentially epitaxially to obtain the first preform.

[0018] S2. A top electrode is provided on the upper part of the p-type Bragg reflector group of the first preform, and a bottom electrode is provided on the lower part of the substrate of the first preform to complete the fabrication of the laser.

[0019] The present invention also provides an application of a high refractive index extended cavity vertical cavity surface-emitting laser prepared by the above-described method or by the above-described method.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] 1. The present invention relates to a high refractive index extended cavity vertical cavity surface-emitting laser, wherein the introduction of an n-type extended layer can effectively increase the effective cavity length of the laser, and the n-type extended layer is set as

[0022] Al x Ga 1-x As / Al y Ga 1-y The use of As material suppresses resistance and free carrier absorption in the extended layer, effectively increasing the effective cavity length of the laser, thus increasing the resonant cavity length, increasing the output power, and reducing the linewidth enhancement factor α, thereby narrowing the spectral linewidth. This allows for an increase in the effective cavity length of the laser, achieving a cold cavity linewidth Δλc of 0.05422 nm, and a spectral linewidth of approximately 6 MHz under 1 mW operating power conditions.

[0023] 2. The fabrication method involved in this invention produces a laser with an output spectral linewidth of less than 20 MHz, which is more than two orders of magnitude smaller than that of traditional vertical-cavity surface-emitting lasers, demonstrating significant advantages and thus offering greater application potential. It can be applied to specialized fields such as atomic clocks, demonstrating superior performance. Simultaneously, it avoids the drawbacks of increasing the size, low integration, and complex optical path system associated with increasing the external cavity length of the laser, and eliminates the need for an external cavity system, resulting in simpler operation and lower cost.

[0024] 3. The high-refractive-index extended-cavity vertical-cavity surface-emitting laser (VCSEL) involved in this invention has a wide range of applications. Its linewidth is more than two orders of magnitude smaller than that of traditional VCSELs, exhibiting significantly superior performance. Therefore, it has a wider range of applications and can be used in specialized fields such as atomic clocks, demonstrating its superiority. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a high-refractive-index extended cavity vertical-cavity surface-emitting laser.

[0026] Figure 2 This is a schematic diagram of the refractive index distribution and electric field distribution of the high refractive index extended cavity vertical cavity surface-emitting laser 3 in Example 3.

[0027] Figure 3 This is a schematic diagram of the full width at half maximum (FWHM) of the cold cavity reflection spectrum of the high refractive index extended cavity vertical cavity surface-emitting laser 3 in Example 3.

[0028] Figure 4 This is a LIV curve of the high refractive index extended cavity vertical cavity surface-emitting laser 3 in Example 3. Figure description: 1-Top electrode, 2-P-type Bragg mirror group, 3-Oxide layer, 4-Active region, 5-N-type extended layer, 6-N-type Bragg mirror group, 7-Bottom electrode, 8-Substrate.

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0030] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Detailed Implementation

[0031] See Figure 1As shown, a high-refractive-index extended-cavity vertical-cavity surface-emitting laser (VCSEL) comprises, from top to bottom, a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode. The n-type extended layer is Al. y Ga 1-y As, where y is 0.1 to 0.9.

[0032] Understandably, the laser of the present invention can effectively increase the effective cavity length of the laser by setting an n-type extension layer, and the n-type extension layer is set as Al. x Ga 1-x As / Al y Ga 1-y The use of As material suppresses resistance and free carrier absorption in the extended layer, avoiding the drawbacks of increasing the laser's external cavity length, such as increased volume, low integration, and complex optical path system. Furthermore, it eliminates the need for an external cavity system, simplifying operation and reducing cost. This allows for an increase in the effective cavity length of the laser, achieving a cold cavity linewidth Δλc of 0.05422 nm, and a spectral linewidth of approximately 6 MHz under 1 mW operating power.

[0033] Specifically, the principle is explained: the spectral linewidth of a laser mainly comes from phase fluctuations, including the laser's own vibrations, phase changes caused by external noise, and phase changes caused by quantum fluctuations. Among these, the main reason is the phase fluctuations caused by spontaneous emission.

[0034] According to the Schawlow-Townes laser linewidth principle: Δν=(hv / P0)(v / λ) 2 (πη0n sp )(Δλ c ) 2 (1+α 2 ), where Δλ c is the linewidth of the cold cavity (ignoring active region gain or loss), which is the wavelength difference corresponding to 50% reflectivity, hv is the photon energy, P0 is the output power, and n sp It is the spontaneous emission factor. Studies have shown that the spectral linewidth of a laser is mainly related to the laser's output power, linewidth enhancement factor α, and resonant cavity length.

[0035] When the gain is not saturated, increasing the output power stabilizes spontaneous emission and reduces the spectral linewidth. The linewidth enhancement factor α is related to the ratio of the real to the imaginary part of the source region's refractive index to the injected carrier concentration; the linewidth can be narrowed by decreasing α. Increasing the cavity length improves the cavity's quality factor; the more stable the frequency, the narrower the spectral linewidth. Because the laser emitted by a vertical-cavity surface-emitting laser not only oscillates in the active region, the optical field also extends into the upper and lower DBR mirrors.

[0036] Therefore, the effective cavity length L is used. eff Indicates: L eff =L cavity +L top +L bottom L top L bottom These represent the lengths by which light penetrates into the upper and lower Bragg reflector groups, respectively.

[0037] This invention effectively increases the effective cavity length of a laser by setting an n-type extension layer, and sets the n-type extension layer as Al. x Ga 1-x As / Al y Ga 1-y The use of As material increases the resonant cavity length, increases the output power, and reduces the linewidth enhancement factor α, thereby achieving narrowing of the spectral linewidth.

[0038] It should be noted that the refractive index of the extended layer can be high or low, without limitation. However, the electrical properties of extended layers with low refractive index are not as good as those of extended layers with high refractive index.

[0039] An n-type extension layer is formed by extending the first n-type DBR layer close to the active region. Alternatively, a p-type extension layer can be formed by extending the first p-type DBR layer close to the active region. However, p-type extension layers have higher losses and do not have the superior electrical performance of n-type extension layers.

[0040] In some embodiments of the present invention, the thickness of the n-type extended layer is 0.8–2.5 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 ~2.2×10 18 cm -3 .

[0041] Specifically, the n-type extended layer has a thickness of 2 μm and a doping concentration of 2 × 10⁻⁶. 18 cm -3 .

[0042] In some embodiments of the present invention, the p-type Bragg reflector group consists of 20 to 25 pairs of p-type Al. x Ga 1-x As / Al y Ga 1-y As, where x is 0.88 to 0.92 and y is 0.1 to 0.16.

[0043] Specifically, the p-type Bragg mirror group consists of 23 pairs of Al 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 As.

[0044] In some embodiments of the present invention, the p-type Al x Ga 1-x As / Al y Ga 1-y As doping concentration 2×10 18 cm -3 ~3×10 18 cm -3 .

[0045] Specifically, the p-type Al x Ga 1-x As / Al y Ga 1-y The As doping concentration is 3 × 10⁻⁶. 18 cm -3 .

[0046] In some embodiments of the present invention, the n-type Bragg mirror group consists of 32 to 40 pairs of n-type Al. x Ga 1-x As / Al y Ga 1-y As, where x is 0.88 to 0.92 and y is 0.1 to 0.16.

[0047] Specifically, the n-type Bragg mirror group consists of 36 pairs of Al 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 As.

[0048] In some embodiments of the present invention, the n-type Al x Ga 1-x As / Al y Ga 1-y The As doping concentration is 1.8 × 10⁻⁶. 18 cm -3 ~2.2×10 18 cm -3 .

[0049] Specifically, the n-type Al x Ga 1-x As / Al y Ga 1-y The As doping concentration is 2 × 10⁻⁶. 18 cm -3 .

[0050] It should be noted that while p-type and n-type Bragg mirror arrays can be formed by a step change between high and low refractive indices in the refractive index layer, this is not necessary. For example, the bottom n-type Bragg mirror array and the top p-type Bragg mirror array can be composed of parabolic components, which can alter carrier transport.

[0051] Specifically, if a graded layer is added between each pair of Bragg mirrors with high and low refractive indices, and the graded layer is Al... x Ga 1-x As, Al x Ga 1-x The as composition varies from x to 0.12; the thickness of the gradient layer is 10 to 20 nm. The series connection between adjacent P-type / N-type Bragg reflectors generates series resistance. By using a gradient layer, the resistance between adjacent P-type and / or N-type Bragg reflectors can be reduced. This improves the overall efficiency of the vertical-cavity surface-emitting laser when the driving current must pass through the n-type and / or p-type Bragg reflector groups.

[0052] In some embodiments of the present invention, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 1.8 × 10⁻⁶ 18 cm -3 ~2.2×10 18 cm -3 The thickness is 20-30 nm.

[0053] Specifically, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 2×10 18 cm -3 The thickness is 30nm.

[0054] In some embodiments of the present invention, the oxide layer is provided with several oxide pores with a diameter of 3.0 to 4.0 μm.

[0055] Specifically, the oxide layer has several oxide pores with a diameter of 3.5 μm.

[0056] It should be noted that in the high refractive index extended cavity vertical cavity surface-emitting laser described in this invention, the semiconductor materials used to form the p-type Bragg mirror group, the n-type Bragg mirror group, and each of the active regions are substantially lattice-matched. The p-type Bragg mirror group, the n-type Bragg mirror group, and the active region can be composed of various Il-VI or III-V semiconductor materials.

[0057] The active region, when excited by an electric current, can be used to generate a laser beam. The materials of the active region include at least one of GaP, GaAs, AlGaAs, InGaAs, InGaAsP, InAlGaAs, AlGaAsSb, GaN, AlSb, AlN, AlGaN, AlAs, InP, GaSb, InAs, InSb, HgTe, HgSe, ZnTe, CdS, ZnSe, ZnS, ZnO, Ga2O3, III-V, and II-VI materials.

[0058] It is understandable that an oxide layer, set to 20–30 nm p-type Al, is placed between the active region and the p-type Bragg mirror assembly. 0.98 Ga 0.02 As, it causes lateral oxidation to produce Al2O3, forming an oxide confinement layer with good insulation properties.

[0059] In addition to limiting the aperture of the light-emitting region, the oxide confinement layer of this invention can also effectively suppress electron leakage, enabling the vertical-cavity surface-emitting laser to achieve low-threshold single-mode laser output. Furthermore, since the refractive index of the oxide confinement layer is lower than that of the quantum well material, the optical field can be effectively confined within the oxide confinement layer.

[0060] In terms of optical field design, this invention reduces device absorption loss by precisely controlling the active region (antinode) and the oxide confinement layer (node) at the standing wave position in the optical field.

[0061] Furthermore, the size of the oxide aperture has a significant impact on the near-field mode and threshold current of the laser; the smaller the oxide aperture, the lower the threshold current of the laser. The oxide aperture diameter in this invention is 3.0–4.0 μm, enabling the narrow-linewidth laser to maintain low threshold current and single-mode characteristics, confining the current to the center of the device, and allowing the VCSEL to primarily emit in the fundamental transverse mode.

[0062] In some embodiments of the present invention, the effective cavity length of the laser is 3.8 to 4.2 μm.

[0063] Understandably, increasing the effective cavity length of the VCSEL results in a cold cavity linewidth Δλc of 0.05422 nm. Under operating conditions with a power of 1 mW, the spectral linewidth can reach approximately 6 MHz.

[0064] In some embodiments of the present invention, the top electrode and / or bottom electrode are made of any one of gold, copper, graphite, silver or tin.

[0065] This invention also provides a method for fabricating a high-refractive-index extended-cavity vertical-cavity surface-emitting laser, comprising the following steps:

[0066] S1. On the substrate, an n-type Bragg mirror assembly, an n-type extended layer, an active region, an oxide layer, and a p-type Bragg mirror assembly are sequentially epitaxially to obtain the first preform.

[0067] S2. A top electrode is provided on the upper part of the p-type Bragg reflector group of the first preform, and a bottom electrode is provided on the lower part of the substrate of the first preform to complete the fabrication of the laser.

[0068] It should be noted that during the specific epitaxial process, there are buffer layers between the n-type Bragg mirror group, the n-type extended layer, the active region, the oxide layer, and the p-type Bragg mirror group. The parameters are adjusted according to the actual fabrication requirements to perform epitaxy on each buffer layer to meet the actual needs.

[0069] This invention achieves superior laser performance by sequentially epitaxially layering layers on a substrate and adjusting the material, doping concentration, and thickness of each layer. This creates an n-type extension layer between the active region and the n-type Bragg mirror assembly, while controlling the oxide aperture diameter to 3.0–4.0 μm. Simultaneously, it avoids the drawbacks of increasing the laser's external cavity length, such as increased volume, low integration, and complex optical path, and eliminates the need for an external cavity system, resulting in simpler operation and lower cost.

[0070] In some embodiments of the present invention, the preparation method of the present invention may use metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) to epitaxially grow each layer.

[0071] The preferred preparation method of the present invention is to use metal-organic chemical vapor deposition (MOCVD) to epitaxially deposit each layer.

[0072] The present invention also provides an application of a high refractive index extended cavity vertical cavity surface-emitting laser prepared by the above-described method or by the above-described method.

[0073] The laser fabricated in this invention achieves an output spectral linewidth of less than 20 MHz, which is more than two orders of magnitude smaller than that of traditional vertical-cavity surface-emitting lasers (VCSELs). This demonstrates significantly superior performance and thus offers greater application potential. It can be applied in specialized fields such as atomic clocks, demonstrating its superiority.

[0074] Example 1

[0075] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 1, comprising, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.1 Ga 0.9 As.

[0076] In this embodiment, the thickness of the n-type extended layer is 1.95 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 .

[0077] In this embodiment, the p-type Bragg reflector group consists of 20 pairs of p-type Al... 0.9 Ga 0.1 As / Al 0.12 Ga 0.88 As.

[0078] The p-type n-type Al in this embodiment 0.9 Ga 0.1 As / Al 0.12 Ga 0.88 The As doping concentration is 2.8 ×

[0079] 10 18 cm -3 .

[0080] In this embodiment, the n-type Bragg mirror group consists of 31 pairs of n-type Al. 0.9 Ga 0.1 As / Al 0.12 Ga 0.88 As.

[0081] The n-type Al described in this embodiment 0.9 Ga 0.1 As / Al 0.12 Ga 0.88 The As doping concentration is 1.85 × 10⁻⁶. 18 cm -3 .

[0082] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, the doping concentration ranges from 1.85×

[0083] 10 18 cm -3 The thickness is 28.5nm.

[0084] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.25 μm.

[0085] Its preparation method includes the following steps:

[0086] S1. On the substrate, an n-type Bragg mirror assembly, an n-type extended layer, an active region, an oxide layer, and a p-type Bragg mirror assembly are sequentially epitaxially to obtain the first preform.

[0087] S2. A top electrode is provided on the upper part of the p-type Bragg mirror group of the first preform, and a bottom electrode is provided on the lower part of the substrate of the first preform, thereby completing the fabrication of the high refractive index extended cavity vertical cavity surface emission laser 1.

[0088] Example 2

[0089] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 2, comprising, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.13 Ga 0.87 As.

[0090] In this embodiment, the thickness of the n-type extended layer is 2.05 μm, and the doping concentration is 1.9 × 10⁻⁶. 18 cm -3 .

[0091] In this embodiment, the p-type Bragg mirror group consists of 22 pairs of p-type Al. 0.91 Ga 0.09 As / Al 0.13 Ga 0.87 As.

[0092] The p-type Al described in this embodiment 0.91 Ga 0.09 As / Al 0.13 Ga 0.87 The As doping concentration is 2.8 × 10⁻⁶. 18 cm -3 .

[0093] In this embodiment, the n-type Bragg mirror group consists of 34 pairs of n-type Al. 0.91 Ga 0.09 As / Al 0.13 Ga 0.87 As.

[0094] The n-type Al described in this embodiment 0.91 Ga 0.09 As / Al 0.13 Ga 0.87 The As doping concentration is 1.8×

[0095] 10 18 cm -3 .

[0096] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 1.9 × 10⁻⁶ 18 cm -3 The thickness is 29nm.

[0097] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.2 μm.

[0098] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser 2 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0099] Example 3

[0100] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 3, comprising, from top to bottom: a top electrode, a p-type Bragg mirror group, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror group, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.14 Ga 0.86 As.

[0101] In this embodiment, the thickness of the n-type extended layer is 2.01 μm, and the doping concentration is 2.1 × 10⁻⁶. 18 cm -3 .

[0102] In this embodiment, the p-type Bragg mirror group consists of 23 pairs of p-type Al. 0.92 Ga 0.08 As / Al 0.14 Ga 0.86 As.

[0103] The Al described in this embodiment 0.92 Ga 0.08 As / Al 0.14 Ga 0.86 The As doping concentration is 3.0 × 10⁻⁶. 18 cm -3 .

[0104] In this embodiment, the n-type Bragg mirror group consists of 34 pairs of n-type Al. 0.92 Ga 0.08 As / Al 0.14 Ga 0.86 As.

[0105] The n-type Al described in this embodiment 0.92 Ga 0.08 As / Al 0.14 Ga 0.86 The As doping concentration is 1.96×

[0106] 10 18 cm -3 .

[0107] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, the doping concentration range is 2.15×

[0108] 10 18 cm -3 The thickness is 20nm.

[0109] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.35 μm.

[0110] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 3 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0111] Example 4

[0112] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 4, comprising, from top to bottom: a top electrode, a p-type Bragg mirror group, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror group, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.15 Ga 0.85 As.

[0113] In this embodiment, the thickness of the n-type extended layer is 2.01 μm, and the doping concentration is 2.05 × 10⁻⁶. 18 cm -3 .

[0114] In this embodiment, the p-type Bragg mirror group consists of 23 pairs of p-type Al. 0.9 Ga 0.1 As / Al 0.15 Ga 0.85 As.

[0115] The p-type Al described in this embodiment 0.9 Ga 0.1 As / Al 0.15 Ga 0.85 The As doping concentration is 2.5 × 10⁻⁶. 18 cm -3

[0116] In this embodiment, the n-type Bragg mirror group consists of 38 pairs of n-type Al. 0.89 Ga 0.11 As / Al 0.15 Ga 0.85 As.

[0117] The n-type Al described in this embodiment 0.95 Ga 0.05 As / Al 0.15 Ga 0.85 The As doping concentration is 1.86×

[0118] 10 18 cm -3 .

[0119] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, the doping concentration ranges from 2.05×

[0120] 10 18 cm -3 The thickness is 28nm.

[0121] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.1 μm.

[0122] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 4 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0123] Example 5

[0124] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 5, comprising, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.16 Ga 0.84 As.

[0125] In this embodiment, the thickness of the n-type extended layer is 2.05 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 .

[0126] In this embodiment, the p-type Bragg mirror group consists of 23 pairs of p-type Al. 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 As.

[0127] The p-type Al described in this embodiment 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 The As doping concentration is 2.8 × 10⁻⁶. 18 cm -3 .

[0128] In this embodiment, the n-type Bragg mirror group consists of 39 pairs of n-type Al. 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 As.

[0129] The n-type Al described in this embodiment 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 The As doping concentration is 2.12×

[0130] 10 18 cm -3 .

[0131] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 2.0 × 10⁻⁶ 18 cm -3 The thickness is 20.5nm.

[0132] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.25 μm.

[0133] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser 5 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0134] Example 6

[0135] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 6, comprising, from top to bottom: a top electrode, a p-type Bragg mirror group, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror group, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.17 Ga 0.83 As.

[0136] In this embodiment, the thickness of the n-type extended layer is 2.05 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 .

[0137] In this embodiment, the p-type Bragg mirror group consists of 24 pairs of p-type Al. 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 As.

[0138] The p-type Al described in this embodiment 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 The As doping concentration is 2.8 × 10⁻⁶. 18 cm -3 .

[0139] In this embodiment, the n-type Bragg mirror group consists of 33 pairs of n-type Al. 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 As.

[0140] The n-type Al described in this embodiment 0.92 Ga 0.08 As / Al 0.16Ga 0.84 The As doping concentration is 2.12×

[0141] 10 18 cm -3 .

[0142] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 2.1 × 10⁻⁶ 18 cm -3 The thickness is 28nm.

[0143] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.3 μm.

[0144] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser 6 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0145] Example 7

[0146] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 7, comprising, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.18 Ga 0.82 As.

[0147] In this embodiment, the thickness of the n-type extended layer is 2.05 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 .

[0148] In this embodiment, the p-type Bragg reflector group consists of 21 pairs of p-type Al... 0.88 Ga 0.12 As / Al 0.1 Ga 0.9 As.

[0149] The p-type Al described in this embodiment 0.88 Ga 0.12 As / Al 0.1 Ga 0.9 The As doping concentration is 2.8 × 10⁻⁶. 18 cm -3 .

[0150] In this embodiment, the n-type Bragg mirror group consists of 35 pairs of n-type Al... 0.9 Ga 0.1 As / Al 0.15 Ga 0.85 As.

[0151] The n-type Al described in this embodiment0.9 Ga 0.1 As / Al 0.15 Ga 0.85 The As doping concentration is 2.12 × 10⁻⁶. 18 cm -3 .

[0152] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 2.0 × 10⁻⁶ 18 cm -3 The thickness is 29nm.

[0153] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.4 μm.

[0154] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser 7 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0155] Example 8

[0156] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 8, comprising, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.16 Ga 0.84 As.

[0157] In this embodiment, the thickness of the n-type extended layer is 2.05 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 .

[0158] In this embodiment, the p-type Bragg mirror group consists of 23 pairs of p-type Al. 0.9 Ga 0.1 As / Al 0.16 Ga 0.84 As.

[0159] The p-type Al described in this embodiment 0.9 Ga 0.1 As / Al 0.16 Ga 0.84 The As doping concentration is 2.8 × 10⁻⁶. 18 cm -3 .

[0160] In this embodiment, the n-type Bragg mirror group consists of 39 pairs of n-type Al. 0.88 Ga 0.12 As / Al 0.16 Ga 0.84 As.

[0161] The n-type Al described in this embodiment 0.88 Ga 0.12 As / Al 0.16 Ga 0.84 The As doping concentration is 2.12×

[0162] 10 18 cm -3 .

[0163] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 2.0 × 10⁻⁶ 18 cm -3 The thickness is 28nm.

[0164] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.25 μm.

[0165] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser 8 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0166] Example 9

[0167] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 9, comprising, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.17 Ga 0.83 As.

[0168] In this embodiment, the thickness of the n-type extended layer is 2.05 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 .

[0169] In this embodiment, the p-type Bragg mirror group consists of 23 pairs of p-type Al. 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 As.

[0170] The p-type Al described in this embodiment 0.92 Ga 0.08 As / Al 0.16 Ga 0.84 The As doping concentration is 2.8 × 10⁻⁶. 18 cm -3 .

[0171] In this embodiment, the n-type Bragg mirror group consists of 39 pairs of n-type Al. 0.91 Ga 0.09 As / Al 0.13 Ga0.87 As.

[0172] The n-type Al described in this embodiment 0.91 Ga 0.09 As / Al 0.13 Ga 0.87 The As doping concentration is 2.12×

[0173] 10 18 cm -3 .

[0174] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 2.0 × 10⁻⁶ 18 cm -3 The thickness is 23nm.

[0175] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.45 μm.

[0176] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser 9 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0177] Example 10

[0178] A high-refractive-index extended cavity vertical-cavity surface-emitting laser 10, comprising, from top to bottom: a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode, wherein the n-type extended layer is Al. 0.13 Ga 0.87 As.

[0179] In this embodiment, the thickness of the n-type extended layer is 2.05 μm, and the doping concentration is 1.8 × 10⁻⁶. 18 cm -3 .

[0180] In this embodiment, the p-type Bragg reflector group consists of 21 pairs of p-type Al... 0.88 Ga 0.12 As / Al 0.13 Ga 0.87 As.

[0181] The p-type Al described in this embodiment 0.88 Ga 0.12 As / Al 0.13 Ga 0.87 The As doping concentration is 2.8 × 10⁻⁶. 18 cm -3 .

[0182] In this embodiment, the n-type Bragg mirror group consists of 35 pairs of n-type Al...0.89 Ga 0.11 As / Al 0.13 Ga 0.87 As.

[0183] The n-type Al described in this embodiment 0.89 Ga 0.11 As / Al 0.13 Ga 0.87 The As doping concentration is 2.12×

[0184] 10 18 cm -3 .

[0185] In this embodiment, the oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 2.0 × 10⁻⁶ 18 cm -3 The thickness is 24.6nm.

[0186] In this embodiment, the oxide layer has several oxide pores with a diameter of 3.32 μm.

[0187] A high-refractive-index extended-cavity vertical-cavity surface-emitting laser 10 was prepared according to the preparation method of Example 1. The specific steps are not described in detail here.

[0188] Experimental Example 1. Refractive index distribution and electric field distribution of the laser of the present invention

[0189] 1.1 Experimental Design

[0190] The high-refractive-index extended-cavity vertical-cavity surface-emitting laser 3 involved in Example 3 was selected, and its refractive index distribution and electric field distribution were analyzed. The analysis results are shown in […]. Figure 2 , Figure 3 .

[0191] 1.2 Results Analysis

[0192] See Figure 2 and Figure 3 High-refractive-index extended cavity vertical-cavity surface-emitting laser 3 Figure 2 The simulated optical field profile near the active region is shown. The thick line represents the true refractive index, and the thin line represents the resonant cavity standing wave. The thickness of the first high-refractive-index n-DBR period near the active region is increased, resulting in a significant increase in the effective cavity length compared to conventional VCSEL designs.

[0193] like Figure 3 As shown, for a typical VCSEL laser, the cold cavity linewidth Δλ cGenerally greater than 0.2 nm, for VCSEL lasers with output optical power less than 1 mW, the output spectral linewidth can reach over 1 GHz. For asymmetric cavity-tuned narrow-linewidth VCSELs, due to the increase in effective cavity length, the cold cavity linewidth can reach below 0.1 nm. With an output optical power of 10 mW, the Δλ of the asymmetric cavity-tuned narrow-linewidth VCSEL... c At a wavelength of 0.05422 nm, theoretical calculations show that the laser's output spectral linewidth can reach approximately 6 MHz, which is more than two orders of magnitude smaller than that of a traditional VCSEL. Example 2. Electrical performance testing of the laser of this invention.

[0194] 1.1 Experimental Design

[0195] The high-refractive-index extended-cavity vertical-cavity surface-emitting laser 3 involved in Example 3 was selected, and its electrical performance was tested. The analysis results are shown in […]. Figure 4 .

[0196] 1.2 Results Analysis

[0197] See Figure 4 The laser threshold current of Embodiment 3 of this invention can reach 0.69 mA, the turn-on voltage is 1.31 V, the slope efficiency is 0.901 W / A, and the maximum photoelectric conversion efficiency (PCE) reaches 56.33%. It is evident that the high-refractive-index extended-cavity vertical-cavity surface-emitting laser of this invention possesses excellent electrical performance and superior capabilities.

[0198] In summary, the high refractive index extended cavity vertical cavity surface-emitting laser of this invention effectively increases the effective cavity length of the laser by introducing an n-type extension layer, and the n-type extension layer is set as Al. x Ga 1-x As / Al y Ga 1-y The use of As material suppresses resistance and free carrier absorption in the extended layer, which can effectively increase the effective cavity length of the laser, increase the resonant cavity length, increase the output power, and reduce the linewidth enhancement factor α, thereby achieving narrowing of the spectral linewidth.

[0199] Experimental verification shows that the fabrication method involved in this invention increases the effective cavity length of the laser, achieving a cold cavity linewidth Δλc of 0.05422 nm. Under operating conditions of 1 mW power, the spectral linewidth can reach approximately 6 MHz. This solves the problems of large linewidth in existing vertical-cavity surface-emitting lasers and the difficulty in controlling narrow linewidth in current technologies.

[0200] The above embodiments are merely one implementation of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A high-refractive-index extended-cavity vertical-cavity surface-emitting laser, characterized in that, The laser, from top to bottom, includes a top electrode, a p-type Bragg mirror assembly, an oxide layer, an active region, an n-type extended layer, an n-type Bragg mirror assembly, a substrate, and a bottom electrode. The n-type extended layer is Al. y Ga 1-y As, where y is greater than or equal to 0.1 and less than 0.9; the thickness of the n-type extended layer is 0.8~2.5μm, and the doping concentration is 1.8×10⁻⁶. 18 cm -3 ~2.2×10 18 cm -3 The oxide layer is p-type Al. 0.98 Ga 0.02 As, doping concentration range is 1.8 × 10⁻⁶ 18 cm -3 ~2.2×10 18 cm -3 The oxide layer has a thickness of 20~30nm; the oxide layer has several oxide pores with a diameter of 3.0~4.0μm.

2. A high-refractive-index extended-cavity vertical-cavity surface-emitting laser according to claim 1, characterized in that, The p-type Bragg mirror group consists of 20-25 pairs of p-type Al. x Ga 1-x As / Al y Ga 1-y As, where x is 0.88~0.92 and y is 0.1~0.

16.

3. A high-refractive-index extended-cavity vertical-cavity surface-emitting laser according to claim 2, characterized in that, p-type Al x Ga 1-x As / Al y Ga 1-y As doping concentration 2×10 18 cm -3 ~3×10 18 cm -3 .

4. A high-refractive-index extended-cavity vertical-cavity surface-emitting laser according to claim 1, characterized in that, The n-type Bragg mirror group consists of 32-40 pairs of n-type Al. x Ga 1-x As / Al y Ga 1-y As, where x is 0.88~0.92 and y is 0.1~0.

16.

5. A high-refractive-index extended-cavity vertical-cavity surface-emitting laser according to claim 4, characterized in that, The n-type Al x Ga 1-x As / Al y Ga 1-y The As doping concentration is 1.8 × 10⁻⁶. 18 cm -3 ~2.2×10 18 cm -3 .

6. A method for fabricating a high refractive index extended cavity vertical cavity surface-emitting laser according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. On the substrate, an n-type Bragg mirror assembly, an n-type extended layer, an active region, an oxide layer, and a p-type Bragg mirror assembly are sequentially epitaxially to obtain the first preform. S2. A top electrode is provided on the upper part of the p-type Bragg reflector group of the first preform, and a bottom electrode is provided on the lower part of the substrate of the first preform to complete the fabrication of the laser.

7. Application of a high refractive index extended cavity vertical cavity surface-emitting laser based on any one of claims 1 to 5 or prepared by claim 6.

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