A blue laser

Abstract

This invention discloses a blue laser, which includes a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer stacked sequentially from bottom to top, and further includes a first stress modulation layer and a second stress modulation layer; the lower confinement layer includes a first lower confinement layer and a second lower confinement layer; the lower confinement layer has the first lower confinement layer, the first stress modulation layer, and the second lower confinement layer disposed from bottom to top; the second stress modulation layer is disposed between the second lower confinement layer and the lower waveguide layer; the first stress modulation layer and the second stress modulation layer are used together to release the lattice mismatch stress between the substrate and the lower confinement layer and the thermal mismatch stress between the substrate and the lower confinement layer. Using the embodiments of this invention, by disposing of stress modulation layers in the lower confinement layer and between the lower confinement layer and the lower waveguide layer, dual stress modulation is achieved, thereby suppressing substrate mode leakage, improving laser refractive index dispersion, and enhancing the laser's electro-lasing gain.

Description

Technical Field

[0001] This invention relates to the field of semiconductor optoelectronics technology, and more particularly to a blue laser. Background Technology

[0002] Lasers are widely used in laser displays, laser TVs, laser projectors, communications, medical applications, weaponry, guidance, ranging, spectral analysis, cutting, precision welding, and high-density optical storage. There are many types of lasers, and they can be classified in various ways, mainly including solid-state, gas, liquid, semiconductor, and dye lasers. Compared with other types of lasers, all-solid-state semiconductor lasers have advantages such as small size, high efficiency, light weight, good stability, long lifespan, simple and compact structure, and miniaturization.

[0003] There are significant differences between lasers and nitride semiconductor light-emitting diodes (LEDs): 1) Lasers are generated by stimulated emission of charge carriers, resulting in a narrow spectral width at half maximum (FW / HM) and very high brightness; a single laser can achieve output power in the W range. In contrast, nitride LEDs are generated through spontaneous emission, with output power in the mW range. 2) Lasers operate at current densities of up to kA / cm², more than two orders of magnitude higher than nitride LEDs. This leads to stronger electron leakage, more severe Auger recombination, stronger polarization effects, and more severe electron-hole mismatch, resulting in a more severe drop effect and efficiency degradation. 3) The LED... In a light-emitting diode (LED), spontaneous transition radiation occurs without external influence, producing incoherent light from a high energy level to a low energy level. In contrast, lasers emit stimulated transition radiation, where the energy of the induced photon must equal the energy difference between the electron and the transition energy levels to produce coherent light. 4) The principles differ: LEDs emit light through radiative recombination when electrons and holes transition to the active layer or pn junction under external voltage. Lasers, however, require specific lasing conditions to be met. Specifically, the active region must have a reversed carrier distribution, and the stimulated emission light oscillates within the resonant cavity. Propagation in the gain medium amplifies the light, satisfying the threshold condition to ensure the gain exceeds the loss, ultimately resulting in laser output. Existing lasers primarily use nitride semiconductor lasers. However, nitride semiconductor lasers suffer from strong piezoelectric polarization due to lattice mismatch and large strain, leading to increased bandgap in the valence band and difficulty in hole transport, ultimately limiting the laser's electro-lasing gain. Summary of the Invention

[0004] This invention provides a blue laser to solve the technical problem of limited electro-lasing gain in existing nitride semiconductor lasers due to lattice mismatch and thermal mismatch stress.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a blue laser, comprising a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer stacked sequentially from bottom to top, and further comprising: a first stress modulation layer and a second stress modulation layer; the lower confinement layer comprises: a first lower confinement layer and a second lower confinement layer;

[0006] The lower limiting layer comprises, from bottom to top, a first lower limiting layer, a first stress modulation layer, and a second lower limiting layer;

[0007] A second stress modulation layer is disposed between the second lower confinement layer and the lower waveguide layer;

[0008] The first stress modulation layer and the second stress modulation layer together are used to release the lattice mismatch stress between the substrate and the lower confinement layer and the thermal mismatch stress between the substrate and the lower confinement layer.

[0009] This invention provides a stress modulation layer between the lower confinement layer and the lower waveguide layer to fully release the lattice mismatch stress and thermal mismatch stress between the substrate and the lower confinement layer, thereby achieving dual stress modulation, suppressing substrate mode leakage, improving laser refractive index dispersion, and enhancing the electro-lasing gain of the green laser.

[0010] Furthermore, the first stress modulation layer is Al x In y Ga 1-x-y N; the second stress modulation layer is Al z Ga 1- z N; the first lower confinement layer is Al. k Ga 1-k N; the second lower confinement layer is Al. m Ga 1-m N; where 0≤x≤z≤k≤m≤1, 0<y<1.

[0011] Furthermore, the thickness of the first stress modulation layer is 10-600 nm; the thickness of the second stress modulation layer is 20-800 nm; the thickness of the first lower confinement layer is 100-6000 nm; and the thickness of the second lower confinement layer is 50-5000 nm.

[0012] Furthermore, the thickness of the first stress modulation layer is less than the thickness of the second stress modulation layer and less than the thickness of the second lower limiting layer.

[0013] This invention modulates the lattice mismatch stress and thermal mismatch stress between the substrate and the lower confinement layer by adjusting the Al composition and thickness of each stress modulation layer and the lower confinement layer, thereby controlling the stress changes between the substrate and the lower confinement layer, suppressing substrate mode leakage, and improving the electro-lasing gain of the green laser.

[0014] Furthermore, the active layer includes a first barrier layer, a first well layer, a second barrier layer, a second well layer, a third barrier layer, a third well layer, and a fourth barrier layer stacked sequentially from top to bottom;

[0015] The first barrier layer is GaN, and the thickness of the first barrier layer is 1-3 nm;

[0016] The first well layer is In p Ga 1-p N, where the thickness of the first well layer is 5-15 nm;

[0017] The second barrier layer is GaN, and the thickness of the second barrier layer is 1-3 nm;

[0018] The second well layer is In q Ga 1-q N, where the thickness of the second well layer is 3-5 nm;

[0019] The third barrier layer is GaN, and the thickness of the third barrier layer is 2-5 nm;

[0020] The third well layer is In s Ga 1-s N, the thickness of the third well layer is 1-3 nm;

[0021] The fourth barrier layer is GaN, and the thickness of the fourth barrier layer is 0.5-3 nm; wherein, 0 < p < q ≤ s < 0.2.

[0022] This invention achieves stress modulation of the quantum well structure in the active layer by varying the In composition of each well layer in the active layer, thereby further suppressing substrate mode leakage and improving the electro-lasing gain of the green laser.

[0023] Furthermore, the thickness of the second well layer is less than the thickness of the third well layer and less than the thickness of the first well layer; the thickness of the fourth barrier layer is less than the thickness of the first barrier layer, less than the thickness of the second barrier layer, and less than the thickness of the third barrier layer.

[0024] The present invention further controls the stress of the quantum well by varying the thickness of each well layer and each barrier layer, thereby suppressing substrate mode leakage and improving the electro-lasing gain of the green laser.

[0025] Furthermore, the first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are all doped with Si; wherein, the Si doping concentration of the second lower confinement layer is ≤ the Si doping concentration of the first lower confinement layer ≤ the Si doping concentration of the second stress modulation layer ≤ the Si doping concentration of the first stress modulation layer.

[0026] The first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are further doped with C; wherein, the C doping concentration of the second stress modulation layer is ≤ the C doping concentration of the first stress modulation layer is ≤ the C doping concentration of the first lower confinement layer is ≤ the C doping concentration of the second lower confinement layer.

[0027] Furthermore, the first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are also doped with H; wherein, the H doping concentration of the first stress modulation layer is ≤ the H doping concentration of the first lower confinement layer is ≤ the H doping concentration of the second stress modulation layer is ≤ the H doping concentration of the second lower confinement layer;

[0028] The first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are further doped with O; wherein, the O doping concentration of the first stress modulation layer is ≤ the O doping concentration of the first lower confinement layer is ≤ the O doping concentration of the second stress modulation layer is ≤ the O doping concentration of the second lower confinement layer.

[0029] Furthermore, the lower waveguide layer is InGaN, and the thickness of the lower waveguide layer is 1-800nm.

[0030] Furthermore, the upper waveguide layer comprises one or more combinations of AlInGaN, AlInN, and AlGaN, and the thickness of the upper waveguide layer is 1-900 nm.

[0031] Furthermore, the substrate is a GaN substrate, and the angle between the C-plane and the M-plane of the substrate is 0.1-1°. Attached Figure Description

[0032] Figure 1 A schematic diagram of a structure of an embodiment of the blue laser provided by the present invention;

[0033] Figure 2 The SIMS secondary ion mass spectrum of an embodiment of the blue laser provided by the present invention;

[0034] Figure 3 SIMS secondary ion mass spectrum of another embodiment of the blue laser provided by the present invention;

[0035] The reference numerals for the accompanying drawings in the specification are as follows:

[0036] 100. Substrate; 101. Lower confinement layer; 101a. First lower confinement layer; 101b. Second lower confinement layer; 102. Dual stress modulation layer; 102a. First stress modulation layer; 102b. Second stress modulation layer; 103. Lower waveguide layer; 104. Active layer; 105. Upper waveguide layer; 106. Upper confinement layer. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please refer to Figure 1 This is a schematic diagram of a blue laser according to an embodiment of the present invention. The blue laser includes a substrate 100, a lower confinement layer 101, a lower waveguide layer 103, an active layer 104, an upper waveguide layer 105, and an upper confinement layer 106 stacked sequentially from bottom to top. It also includes a first stress modulation layer 102a and a second stress modulation layer 102b. The lower confinement layer 101 includes a first lower confinement layer 101a and a second lower confinement layer 101b.

[0039] The lower limiting layer 101 is provided with a first lower limiting layer 101a, a first stress modulation layer 102a, and a second lower limiting layer 101b from bottom to top.

[0040] A second stress modulation layer 102b is disposed between the second lower confinement layer 101b and the lower waveguide layer 103;

[0041] The first stress modulation layer 102a and the second stress modulation layer 102b are used together to release the lattice mismatch stress between the substrate 100 and the lower confinement layer 101 and the thermal mismatch stress between the substrate 100 and the lower confinement layer 101.

[0042] Existing nitride semiconductor lasers suffer from strong piezoelectric polarization due to lattice mismatch and high strain in the active layer, resulting in a strong QCSE (Quantum Confinement SE) Stark effect. This increases the valence band gap, suppresses hole injection, and makes hole transport in the quantum well more difficult, leading to non-uniform carrier injection and gain, thus limiting the improvement of laser electro-lasing gain. Furthermore, the refractive index dispersion and high-concentration carrier concentration fluctuations affect the refractive index of the active layer, causing the confinement factor to decrease with increasing wavelength, resulting in a reduction in mode gain. In this embodiment, the first stress modulation layer 102a and the second stress modulation layer 102b together form a dual stress modulation layer 102, which modulates the lattice mismatch stress and thermal mismatch stress between the substrate 100 and the lower confinement layer 101. This effectively reduces epitaxial cracks in the blue laser, thereby controlling the lattice mismatch, improving refractive index dispersion, increasing the confinement factor, improving mode gain, suppressing mode leakage in the substrate 100, and even improving far-field FFP image quality.

[0043] In this embodiment, the first stress modulation layer 102a is Al x In y Ga 1-x-y N; the second stress modulation layer 102b is Al z Ga 1-z N; the first lower limiting layer 101a is Al k Ga 1-k N; the second lower limiting layer 101b is Al m Ga 1-m N; where 0≤x≤z≤k≤m≤1, 0<y<1.

[0044] In the embodiment, by changing the composition of Al in the first stress modulation layer 102a, Al in the second stress modulation layer 102b, Al in the first lower confinement layer 101a, and Al in the second lower confinement layer 101b, the lattice mismatch stress and thermal mismatch stress between the substrate 100 and the lower confinement layer 101 can be further released.

[0045] In this embodiment, the thickness of the first stress modulation layer 102a is 10-600 nm; the thickness of the second stress modulation layer 102b is 20-800 nm; the thickness of the first lower confinement layer 101a is 100-6000 nm; and the thickness of the second lower confinement layer 101b is 50-5000 nm.

[0046] In an embodiment, the thickness of the first stress modulation layer 102a is less than the thickness of the second stress modulation layer 102b and the thickness of the second lower limiting layer 101b is less than the thickness of the first lower limiting layer 101a.

[0047] This invention modulates the lattice mismatch stress and thermal mismatch stress between the substrate and the lower confinement layer by adjusting the Al composition and thickness of each stress modulation layer and the lower confinement layer. This controls the stress changes between the substrate and the lower confinement layer, suppresses substrate mode leakage, and improves the electro-lasing gain of the green laser. Using embodiments of this invention, the stress modulation range can be controlled within -10% to 10%, reducing the epitaxial crack in the blue laser from 10mm at the edge to 0mm.

[0048] In this embodiment, the active layer 104 includes a first barrier layer, a first well layer, a second barrier layer, a second well layer, a third barrier layer, a third well layer, and a fourth barrier layer stacked sequentially from top to bottom;

[0049] The first barrier layer is GaN, and the thickness of the first barrier layer is 1-3 nm;

[0050] The first well layer is In p Ga 1-p N, where the thickness of the first well layer is 5-15 nm;

[0051] The second barrier layer is GaN, and the thickness of the second barrier layer is 1-3 nm;

[0052] The second well layer is In q Ga 1-q N, where the thickness of the second well layer is 3-5 nm;

[0053] The third barrier layer is GaN, and the thickness of the third barrier layer is 2-5 nm;

[0054] The third well layer is In s Ga 1-s N, the thickness of the third well layer is 1-3 nm;

[0055] The fourth barrier layer is GaN, and the thickness of the fourth barrier layer is 0.5-3nm.

[0056] In this embodiment, the first barrier layer and the first well layer constitute the first active layer, the second barrier layer and the second well layer constitute the second active layer, the third barrier layer and the third well layer constitute the third active layer, and the fourth barrier layer is the last barrier layer; each barrier layer and each well layer together constitute the quantum well structure in the active layer 104, and the emission wavelength of the quantum well structure in this embodiment of the invention is 435-485nm.

[0057] In this embodiment, the In of the first well layer p Ga 1-p N, In of the second well layer q Ga 1-q N and the In of the third well layer s Ga1-s The component relationships among N are: 0 < p < q ≤ s < 0.2.

[0058] This invention modulates the stress in the quantum well structure of the active layer by varying the In composition of each well layer, thereby suppressing substrate mode leakage and improving the electro-lasing gain of the green laser. Using embodiments of this invention, the stress modulation range in the active layer is -5% to 5%, enabling control over the laser piezoelectric polarization, laser refractive index dispersion, and even far-field FFP image quality.

[0059] In this embodiment, the thickness of the second well layer is less than the thickness of the third well layer and less than the thickness of the first well layer; the thickness of the fourth barrier layer is less than the thickness of the first barrier layer, less than the thickness of the second barrier layer, and less than the thickness of the third barrier layer.

[0060] The present invention further controls the stress of the quantum well by varying the thickness of each well layer and each barrier layer, thereby suppressing substrate mode leakage and improving the electro-lasing gain of the green laser.

[0061] In this embodiment, the lower waveguide layer 103 is InGaN, and the thickness of the lower waveguide layer 103 is 1-800nm.

[0062] In this embodiment, the upper waveguide layer 105 includes one or more combinations of AlInGaN, AlInN, and AlGaN, and the thickness of the upper waveguide layer 105 is 1-900 nm.

[0063] In this embodiment, the substrate 100 is a GaN substrate, and the angle of deviation of the substrate 100 from the C-plane to the M-plane is 0.1-1°.

[0064] The present invention further improves the beam quality factor and reduces aging light decay by selecting the substrate deflection angle.

[0065] Please refer to Figure 2 and Figure 3 The figures shown are SIMS secondary ion mass spectra of one embodiment of the blue laser provided by the present invention and another embodiment of the blue laser provided by the present invention, respectively. The doping concentrations of each confinement layer and each stress modulation layer are as follows:

[0066] In this embodiment, the Si doping concentration in the first stress modulation layer 102a is from 10... 18 -10 20 cm -3 The H doping concentration in the first stress modulation layer 102a is 10. 16 -5×10 17 cm -3The C doping concentration in the first stress modulation layer 102a is 10. 15 -10 17 cm -3 The O doping concentration in the first stress modulation layer 102a is 10. 15 -10 17 cm -3 .

[0067] In this embodiment, the Si doping concentration in the second stress modulation layer 102b is from 10... 18 -10 20 cm -3 The H doping concentration in the second stress modulation layer 102b is 10. 16 -5×10 17 cm -3 The C doping concentration in the second stress modulation layer 102b is 10. 15 -10 17 cm -3 The O doping concentration in the second stress modulation layer 102b is 10. 15 -10 17 cm -3 .

[0068] In this embodiment, the Si doping concentration in the first lower confinement layer 101a is from 10... 18 -10 19 cm -3 The H doping concentration in the first lower confinement layer 101a is 10. 16 -10 18 cm -3 The C doping concentration in the first lower confinement layer 101a is 5 × 10⁻⁶. 15 -10 17 cm -3 The doping concentration of O in the first lower confinement layer 101a is 5 × 10⁻⁶. 15 -10 17 cm -3 .

[0069] In this embodiment, the Si doping concentration in the second lower confinement layer 101b is from 10... 18 -10 19 cm -3 The H doping concentration in the second lower confinement layer 101b is 10. 17 -10 18 cm -3 The C doping concentration in the second lower confinement layer 101b is 10. 16 -5×10 17 cm -3The O doping concentration in the second lower confinement layer 101b is 10. 16 -5×10 17 cm -3 .

[0070] In this embodiment, the first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are all doped with Si; wherein, the Si doping concentration of the second lower confinement layer is less than or equal to the Si doping concentration of the first lower confinement layer, less than or equal to the Si doping concentration of the second stress modulation layer, and less than or equal to the Si doping concentration of the first stress modulation layer; the first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are also doped with C; wherein, the C doping concentration of the second stress modulation layer is less than or equal to the C doping concentration of the first stress modulation layer, less than or equal to the C doping concentration of the first lower confinement layer, and less than or equal to the C doping concentration of the second lower confinement layer.

[0071] In this embodiment, the first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are further doped with H; wherein, the H doping concentration of the first stress modulation layer is ≤ the H doping concentration of the first lower confinement layer is ≤ the H doping concentration of the second stress modulation layer is ≤ the H doping concentration of the second lower confinement layer; the first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are further doped with O; wherein, the O doping concentration of the first stress modulation layer is ≤ the O doping concentration of the first lower confinement layer is ≤ the O doping concentration of the second stress modulation layer is ≤ the O doping concentration of the second lower confinement layer.

[0072] The present invention further improves the beam quality factor of the blue laser and mitigates aging-related optical decay by adjusting the H, C, and O concentrations and doping combinations of each stress modulation layer and each confinement layer.

[0073] Using the embodiments of the present invention, the gain of the blue laser is shown in the table below:

[0074] Blue laser - Project Traditional lasers Laser of the present invention range of change Limiting factors 1.40％ 2.70％ 93％ External quantum efficiency 31.50％ 47.60％ 51％

[0075] By controlling the lattice mismatch and improving the refractive index dispersion of the laser, the confinement factor of the blue laser was increased from 1.4% to 2.70%, an improvement of approximately 93%; the external quantum efficiency was increased from 31.5% to 47.6%, an improvement of approximately 51%. Traditional lasers are nitride semiconductor lasers and do not have a stress modulation layer between the lower confinement layer and the lower waveguide layer. This invention, however, by setting a stress modulation layer between the lower confinement layer and the lower waveguide layer, fully releases the lattice mismatch stress and thermal mismatch stress between the substrate and the lower confinement layer, achieving dual stress modulation. This suppresses substrate mode leakage, improves the refractive index dispersion of the laser, and enhances the electro-lasing gain of the green laser.

[0076] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A blue laser, comprising a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer stacked sequentially from bottom to top, characterized in that, Also includes: First stress modulation layer and second stress modulation layer; The lower limiting layer includes: a first lower limiting layer and a second lower limiting layer; The lower limiting layer comprises, from bottom to top, a first lower limiting layer, a first stress modulation layer, and a second lower limiting layer; A second stress modulation layer is disposed between the second lower confinement layer and the lower waveguide layer; The first stress modulation layer and the second stress modulation layer are used together to release the lattice mismatch stress between the substrate and the lower confinement layer and the thermal mismatch stress between the substrate and the lower confinement layer; The first stress modulation layer is Al x In y Ga 1-x-y N; the second stress modulation layer is Al z Ga 1-z N; the first lower confinement layer is Al. k Ga 1-k N; the second lower confinement layer is Al. m Ga 1-m N; where 0≤x≤z≤k≤m≤1, 0<y<1.

2. The blue laser as described in claim 1, characterized in that, The thickness of the first stress modulation layer is 10-600 nm; the thickness of the second stress modulation layer is 20-800 nm; the thickness of the first lower confinement layer is 100-6000 nm; and the thickness of the second lower confinement layer is 50-5000 nm.

3. The blue laser as described in claim 2, characterized in that, The thickness of the first stress modulation layer is less than the thickness of the second stress modulation layer and less than the thickness of the second lower limiting layer.

4. The blue laser as described in any one of claims 1, characterized in that, The active layer includes a first barrier layer, a first well layer, a second barrier layer, a second well layer, a third barrier layer, a third well layer, and a fourth barrier layer stacked sequentially from top to bottom; The first barrier layer is GaN, and the thickness of the first barrier layer is 1-3 nm; The first well layer is In p Ga 1-p N, where the thickness of the first well layer is 5-15 nm; The second barrier layer is GaN, and the thickness of the second barrier layer is 1-3 nm; The second well layer is In q Ga 1-q N, where the thickness of the second well layer is 3-5 nm; The third barrier layer is GaN, and the thickness of the third barrier layer is 2-5 nm; The third well layer is In s Ga 1-s N, the thickness of the third well layer is 1-3 nm; The fourth barrier layer is GaN, and the thickness of the fourth barrier layer is 0.5-3 nm; wherein, 0 < p < q ≤ s < 0.

2.

5. The blue laser as described in claim 4, characterized in that, The thickness of the second well layer is less than the thickness of the third well layer and less than the thickness of the first well layer; the thickness of the fourth barrier layer is less than the thickness of the first barrier layer, less than the thickness of the second barrier layer, and less than the thickness of the third barrier layer.

6. The blue laser as described in any one of claims 1-5, characterized in that, The first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are all doped with Si; wherein, the Si doping concentration of the second lower confinement layer is ≤ the Si doping concentration of the first lower confinement layer is ≤ the Si doping concentration of the second stress modulation layer is ≤ the Si doping concentration of the first stress modulation layer. The first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are further doped with C; wherein, the C doping concentration of the second stress modulation layer is ≤ the C doping concentration of the first stress modulation layer is ≤ the C doping concentration of the first lower confinement layer is ≤ the C doping concentration of the second lower confinement layer.

7. The blue laser as described in any one of claims 1-5, characterized in that, The first stress modulation layer, the second stress modulation layer, the first lower confinement layer and the second lower confinement layer are also doped with H; wherein, the H doping concentration of the first stress modulation layer is ≤ the H doping concentration of the first lower confinement layer is ≤ the H doping concentration of the second stress modulation layer is ≤ the H doping concentration of the second lower confinement layer; The first stress modulation layer, the second stress modulation layer, the first lower confinement layer, and the second lower confinement layer are further doped with O; wherein, the O doping concentration of the first stress modulation layer is ≤ the O doping concentration of the first lower confinement layer is ≤ the O doping concentration of the second stress modulation layer is ≤ the O doping concentration of the second lower confinement layer.

8. The blue laser as described in any one of claims 1-5, characterized in that, The lower waveguide layer is InGaN, and the thickness of the lower waveguide layer is 1-800 nm; the upper waveguide layer includes one or more combinations of AlInGaN, AlInN, and AlGaN, and the thickness of the upper waveguide layer is 1-900 nm.

9. The blue laser as described in any one of claims 1-5, characterized in that, The substrate is a GaN substrate, and the angle between the C-plane and the M-plane of the substrate is 0.1-1°.

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