An elliptical deep trench narrow ridge semiconductor laser

Abstract

The application relates to the field of semiconductor lasers, and discloses an elliptical deep groove narrow ridge semiconductor laser which comprises, from bottom to top, a substrate, an N limiting layer, an N waveguide layer, a quantum hydrazine active layer and a P waveguide layer, the surface of the quantum hydrazine active layer is provided with two shoulder portions, a ridge waveguide is arranged between the two shoulder portions, a groove is formed between the shoulder portions and the ridge waveguide, and elliptical deep grooves are arranged on the two sides of the ridge waveguide, the long arc edges of the elliptical deep grooves intrude into the ridge waveguide to form a narrow ridge waveguide, the elliptical deep groove narrow ridge semiconductor laser suppresses high-order mode participation in laser oscillation through the elliptical deep groove narrow ridge waveguide structure, mode filtering and wave far-field spot optimization of the laser are realized, the purity of the fundamental mode output is effectively improved, and the spot quality is optimized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor lasers, specifically to an elliptical deep-groove narrow-ridge semiconductor laser. Background Technology

[0002] In the information age, optoelectronic technology is the cornerstone of information transmission. Semiconductor lasers, due to their small size, high efficiency, low cost, and long lifespan, are currently the core light source for various optoelectronic devices and are widely used in optical storage, laser displays, laser processing, and laser medical equipment. Single-mode semiconductor lasers, in particular, are widely used in laser pointing, laser processing, optical sensing, and optical communication due to their high beam quality, concentrated beam energy, and ease of coupling into optical fibers. With the development of communication technology, the theoretical speed limit of a single fiber channel is approaching, and multi-aperture fiber technology is an effective means to further improve the bandwidth of optical communication. However, the small mode field area of ​​multi-aperture fibers poses new challenges to the beam quality of existing semiconductor lasers. Improving the purity of the fundamental mode operation of side-emitting lasers has become the main direction of current semiconductor laser research and development. Ridge waveguide edge-emitting semiconductor lasers are currently the most mature and stable semiconductor laser solution. However, due to limitations in their epitaxial growth method and manufacturing process, coupled with errors in the precision control of photolithography and etching processes, the control of defects in active layer materials, and the control of epitaxial layer thickness during large-scale production, the output of the device is not a standard single mode. The existence of other modes leads to poor laser beam quality, which severely limits its application in optical-optical communication, laser processing, and other applications with high beam quality requirements, thus seriously restricting the development and progress of the high-end laser industry.

[0003] To address the challenge of improving beam quality in edge-emitting lasers, two main approaches exist: First, on the ridge waveguide edge-emitting laser chip, structures or materials capable of mode filtering are incorporated around the ridge waveguide, inside the resonant cavity, or within the epitaxial layered structure. This alters the refractive index distribution and shape of the laser resonant cavity, reducing higher-order modes during laser resonance through loss adjustment, gain compensation, or oscillation suppression, thereby increasing the purity of the fundamental mode and achieving high-quality Gaussian beam output. Second, filtering is performed at the laser cavity surface using mode converters, high-precision coatings, and surface waveguide structures to adjust losses. This also effectively enhances fundamental mode competitiveness and suppresses the generation of higher-order modes. The former is currently the primary solution; however, its main limitation is that internal filtering structures increase laser resonant loss, reduce laser current density, and consequently decrease laser efficiency. Furthermore, it places high demands on the precision control of the die manufacturing process, imposing stringent requirements on the accuracy of photolithography and etching processes. The complex epitaxial structure adjustment and mode conversion structures also pose challenges to device cost and chip yield, making it unsuitable for mass production.

[0004] Chinese patent document CN111525391A discloses a semiconductor laser with a three-groove design. While the initial intention of this design was to improve the fast and slow axis ratio of the far-field FFP (Fast-Fluid Pulse) beam through the action of multiple grooves, achieving near-circular beam output, the second groove, through a deep groove design penetrating the active layer, can also achieve beam filtering. The different groove structures need to penetrate the active layer, have small spacing, and the multiple overlay processes increase the complexity of the photolithography steps. The second and third grooves are located on the ridge wave output side; the improvement in the beam spot of the metal layer structure laser comes at the cost of sacrificing the laser's photoelectric conversion efficiency and cost-effectiveness.

[0005] Chinese patent document CN113937616A discloses a ridge waveguide semiconductor laser. This patent describes an epitaxial structure with a ridge waveguide etched on it. A grating is etched on the ridge waveguide near the laser's back cavity surface. The grating includes a mode selection region parallel to the laser's back cavity surface and a mode filtering region forming a preset angle with the laser's back cavity surface. The mode selection region reflects selected transverse modes back into the laser resonant cavity for oscillation and amplification; the mode filtering region reflects unselected transverse modes out of the laser resonant cavity. This patent provides a single semiconductor laser that selects specific transverse modes and filters out other modes through the design of the grating size and morphology, thereby improving the optical field. However, like other grating structures, the calculated grating period, based on the refractive index of the semiconductor material, is relatively small, on the order of wavelength, placing stringent requirements on the photolithography and etching processes. In addition, this patent requires an insulating layer to be covered after the ridge waveguide grating structure is fabricated. However, the insulating layer has poor coverage on the vertical plane, which will greatly increase the risk of short circuit in the device and reduce the yield, making it unsuitable for mass production. Therefore, we propose an elliptical deep groove narrow ridge semiconductor laser. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides an elliptical deep-groove narrow-ridge semiconductor laser, which solves the aforementioned problems.

[0008] (II) Technical Solution

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution: an elliptical deep-groove narrow-ridge semiconductor laser, comprising a substrate, an N-confinement layer, an N-waveguide layer, a quantum hydrazine active layer, and a P-waveguide layer connected sequentially from bottom to top. The surface of the quantum hydrazine active layer is provided with two shoulders, and a ridge waveguide is provided between the two shoulders. A groove is formed between the shoulders and the ridge waveguide. Elliptical deep grooves are provided on both sides of the ridge waveguide. The long arc edge of the elliptical deep grooves penetrates the ridge waveguide to form a narrow ridge waveguide. The diameter of the elliptical deep grooves is between five and one hundred micrometers, and the depth of the elliptical deep grooves is between 0.1 and five micrometers.

[0010] Preferably, the narrowest region of the narrow ridge waveguide is two to thirty micrometers, the long side diameter of the elliptical deep groove is sixty micrometers, the short side diameter is twenty micrometers, and the depth of the elliptical deep groove is one and two micrometers.

[0011] Preferably, the shoulder includes a P-confining layer disposed on the P-waveguide layer. Two sets of protrusions are integrally formed on the P-confining layer, and a rectangular protrusion is integrally formed between the two sets of protrusions, forming a ridge waveguide.

[0012] Preferably, the shoulder includes two P-confining layers with a convex cross-section, the quantum hydrazine active layer and the P-waveguide layer are divided into three parts, the two P-confining layers are located above the P-waveguide layers on both sides respectively, and the ridge waveguide is located above the middle P-waveguide layer.

[0013] Preferably, an ohmic contact layer is provided on the top of the ridge waveguide.

[0014] Preferably, the P-limiting layer is covered with an insulating layer, and the insulating layers on both sides are in contact with the sides of the ohmic contact layer. The top surface of the insulating layer and the ohmic contact layer are covered with a P-side metal layer. The P-side metal layer is at least two of titanium, platinum, gold, nickel, germanium, chromium, and tin, and the thickness of the P-side metal layer is between 200 nanometers and 900 nanometers.

[0015] Preferably, the ridge width of the ridge waveguide is in the range of two μm to two hundred and sixty micrometers, and the height of the ridge waveguide and the depth of the groove are between 0.1 and five micrometers.

[0016] Preferably, the substrate material is at least one of GaAs, InP, and Si;

[0017] Preferably, the N-confinement layer is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the N-confinement layer is between one and three micrometers.

[0018] Preferably, the N-waveguide layer is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the N-waveguide layer is between 90 and 120 nanometers.

[0019] Preferably, the active layer of the quantum hydrazine is a layered structure formed by GaInP, AlGaInP, and GaInP, and the thickness of the active layer of the quantum hydrazine is one to forty nanometers.

[0020] Preferably, the P-waveguide layer is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the P-waveguide layer is between 90 and 120 nanometers.

[0021] Preferably, the P-confining layer is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the P-confining layer is one to three micrometers.

[0022] Preferably, the insulating layer material is any one of SiON confinement layer, SiN waveguide layer, N quantum hydrazine active layer, and AlN. Preferably, the thickness of the insulating layer is fifty to one thousand nanometers.

[0023] Preferably, the cavity length of a single semiconductor laser tube is 250 to 11 micrometers, the width is 150 to 450 micrometers, and the thickness is 100 to 300 micrometers.

[0024] (III) Beneficial Effects

[0025] Compared with the prior art, the present invention provides an elliptical deep-groove narrow-ridge semiconductor laser, which has the following advantages:

[0026] 1. This elliptical deep-groove narrow-ridge semiconductor laser, through a structural design adjacent to the ridge waveguide, introduces an elliptical deep-groove structure on both sides of the ridge waveguide. This design allows higher-order modes (excluding the fundamental mode) within the waveguide to be affected by slight perturbations from the ridge side structures during propagation and oscillation, thus suppressing the competitive advantage of higher-order modes and improving the efficiency of the fundamental mode oscillation. Simultaneously, the symmetrical structure on both sides of the ridge employs a large-diameter circular or elliptical design, and the arc-shaped edges of this structure effectively reduce laser losses introduced by sharp and rough surfaces on the ridge waveguide. Therefore, by suppressing higher-order modes from participating in laser oscillation through the elliptical deep-groove narrow-ridge waveguide structure proposed in this invention, mode filtering and far-field beam optimization are achieved, effectively improving the purity of the fundamental mode output and optimizing the beam quality. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the elliptical deep-groove narrow-ridge semiconductor laser in an embodiment of the present invention;

[0028] Figure 2 This is a cross-sectional view of the elliptical deep-groove narrow-ridge semiconductor laser located at the elliptical groove structure in an embodiment of the present invention;

[0029] Figure 3 This is a cross-sectional view of the elliptical deep-groove narrow-ridge semiconductor laser located at the cavity surface position in an embodiment of the present invention;

[0030] Figure 4This is a top view of the elliptical deep-groove narrow-ridge semiconductor laser in an embodiment of the present invention;

[0031] Figure 5 The diagram shows the transmission of the TE0 fundamental mode within the ridge waveguide structure of an elliptical deep-groove narrow-ridge semiconductor laser. The arrow indicates the location of the elliptical deep-groove region.

[0032] Figure 6 The diagram shows the transmission of the TE1 higher-order mode within the ridge waveguide structure of an elliptical deep-groove narrow-ridge semiconductor laser. The arrow indicates the location of the elliptical deep-groove region.

[0033] Figure 7 The TE0 fundamental mode is shown in the far-field spot pattern.

[0034] Figure 8 The image shows the far-field spot size of the TE1 high-order mode;

[0035] Figure 9 This diagram illustrates the propagation of the TE0 fundamental mode within the ridge waveguide structure of a conventional slotless ridge waveguide semiconductor laser.

[0036] Figure 10 This diagram illustrates the propagation of TE1 higher-order modes within the ridge waveguide structure of a conventional slotless ridge waveguide semiconductor laser.

[0037] In the figure: 1. Substrate; 2. N-confinement layer; 3. N-waveguide layer; 4. Quantum hydrazine active layer; 5. P-waveguide layer; 6. P-confinement layer; 7. Ridge waveguide; 8. Ohmic contact layer; 9. P-plane metal layer; 10. Groove; 11. Shoulder; 12. Elliptical deep trench; 13. Insulating layer. Detailed Implementation

[0038] 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.

[0039] refer to Figures 1 to 3 Example: An elliptical deep-groove narrow-ridge semiconductor laser, wherein... Figure 1A portion of the laser was removed to facilitate observation of its layered internal structure. Compared to elliptical deep-groove narrow-ridge semiconductor lasers, the laser in this embodiment is characterized by: elliptical deep-groove structures 12 positioned in the middle of the laser groove 10, on both sides of the laser's ridge waveguide 7. The long arc edges of the elliptical deep-groove structures 12 penetrate the ridge waveguide 7, forming a narrow ridge waveguide. The diameter of the elliptical deep-groove structures 12 can be arbitrarily selected between 5 and 100 μm (e.g., 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 55 μm, 70 μm, 95 μm, etc.), or other suitable dimensions can be chosen. The depth of the elliptical deep-groove structures 12 can be arbitrarily selected between 0.1 μm and 5 μm.

[0040] Furthermore, the ridge width of the ridge waveguide 7 can be arbitrarily selected between 2μm and 260μm, the length of the ridge waveguide 7 is the same as the cavity length of a single semiconductor laser tube, and the height of the ridge waveguide 7 or the depth of the groove 10 can be arbitrarily selected between 0.1μm and 5μm, or other suitable dimensions can be selected. For example, the width and depth of the ridge waveguide 7 are 3μm and 5μm, respectively, and the long side diameter of the elliptical deep groove is 80μm, the short side diameter is 20μm, and the depth is 2μm.

[0041] In this embodiment, elliptical deep grooves 12 are established on both sides of the ridge waveguide 7. The depth of these grooves exceeds that of the ridge waveguide 7, and the refractive index distribution at these locations is significantly different. By introducing abrupt changes in refractive index, higher-order modes other than the fundamental mode field are interfered with, preventing them from stably existing at the groove locations. Simultaneously, the long arc edges of the groove structure intrude into the ridge waveguide 7, narrowing it and increasing the transmission loss of higher-order modes within the waveguide. This, in turn, filters out higher-order optical fields in the laser, improving the purity of the fundamental mode output and optimizing the beam quality.

[0042] Continue to refer to Figures 1 to 3 In another embodiment, the upper surface of the ridge waveguide 7 of the elliptical deep trench narrow ridge semiconductor laser exemplified in the above embodiment is covered with an ohmic contact layer 8. An insulating layer 13 is covered on the P-confinement layer 6 outside the ridge waveguide 7 region, and the insulating layer 13 contacts both sides of the ridge waveguide 7 but not the ohmic contact layer 8. A P-plane metal layer 9 is covered on the ohmic contact layer 8 and the insulating layer 13 to form a conductive contact region between the P-plane metal layer 9 and the ohmic contact layer 8. The insulating layer is made of SiO2 and has a thickness of 200 nm. Alternatively, the insulating layer can also be made of Si3N4, SiC, AlN, Al2O3, etc., and its thickness can be selected as needed.

[0043] Continue to refer to Figures 1 to 3In another embodiment, the elliptical deep-groove narrow-ridge semiconductor laser exemplified in the above embodiments further includes, from bottom to top, the following layers arranged sequentially: substrate 1, N-type confinement layer 2, N-type waveguide layer 3, quantum hydrazine active layer 4, and P-type waveguide layer 5, with the P-type confinement layer 6 covering the P-type waveguide layer 5. For example, the substrate 1 is made of GaAs. The N-type confinement layer 2 is made of AlInP, with a thickness of 1.05 μm, and the dopant is Si with a doping concentration of 1E16 / cm3. The N-type waveguide layer 3 is made of AlGaInP, with a thickness of 0.1 μm. The quantum hydrazine active layer 4 is a sandwich structure formed by sequentially stacking a quantum well, a barrier, and a quantum hydrazine, with materials corresponding to GaInP, AlGaInP, and GaInP respectively. The barrier has a thickness of 10 nm, and the quantum well has a thickness of 5 nm. The P-type waveguide layer 5 is made of AlGaInP, with a thickness of 0.1 μm. The P-confining layer 6 is made of AlInP material and has a thickness of 1.2 μm. The dopant in the P-confining layer 6 is Mg, with a doping concentration of 1E20 / cm3. The thickness of the P-plane metal layer is 700 nm, and the material of the P-plane metal layer is an alloy formed from titanium and platinum. It should be understood that the materials, dimensions, dopant, etc. of the structural layers illustrated in this embodiment are not limited to the above descriptions. Those skilled in the art can select or adjust them according to actual needs. This embodiment is mainly to more clearly and comprehensively demonstrate the structure of the semiconductor laser described above.

[0044] In another embodiment, a preparation method is provided. Figures 1 to 3 The fabrication method of the elliptical deep-groove narrow-ridge semiconductor laser shown in the example is as follows:

[0045] The laser substrate 1 is a GaAs crystal with a crystal orientation of (100) and a substrate thickness of 500 μm.

[0046] A transition layer was grown on substrate 1 using an MOCVD device. The transition layer material was Si-doped GaAs, and the thickness was 200 nm.

[0047] An N-confined layer 2 is grown on the transition layer using an MOCVD device. The material of the N-confined layer 2 is Si-doped AlInP with a doping concentration of 1-4E18 / cm3 and a thickness of 1000nm.

[0048] The N-confinement layer 2 is covered by an N-waveguide layer 3 grown by an MOCVD device. The material is AlGaInP, and the thickness of the N-waveguide 3 is 90nm~120nm. By adjusting the composition of Al, the AlGaInP is distributed in a gradual manner along the direction perpendicular to the growth plane, with a higher Al composition in the direction away from the GaAs substrate.

[0049] An active layer 4 is grown above the N-waveguide layer 3. The active layer 4 has a structure consisting of GaInP, AlGaInP, and GaInP stacked together to form a double quantum hydrazine sandwich structure active layer from bottom to top. The GaInP layer has a thickness of 5 nm, and the AlGaInP layer has a thickness of 10 nm.

[0050] A P-waveguide layer 5 is grown above the active layer 4. The P-waveguide layer 5 is made of AlGaInP and has a thickness of 90nm~120nm. The Al composition in the material exhibits a gradual distribution along the direction perpendicular to the growth plane, with a higher Al composition in the direction away from the GaAs substrate.

[0051] A P-confining layer 6 is grown above the P-waveguide layer 5. The P-confining layer 6 is made of AlInP and has a thickness of 1200 nm. A GaInP blocking layer is grown in the P-confining layer 6, and the blocking layer is located at the bottom of the P-confining layer 6 at a distance of 200 nm. An AlGaInP blocking layer is located on top of the P-confining layer 6, and the blocking layer has a thickness of 60 nm.

[0052] An ohmic contact layer 8 is grown on the P-confined layer 6. The ohmic contact layer is made of highly doped GaAs and has a thickness of 140 nm.

[0053] After the epitaxial wafer is grown, photoresist is spin-coated onto the surface of the ohmic contact layer 8, followed by ultraviolet lithography, development, and etching. In the photoresist removal step, the ohmic contact layer 8, excluding the ridge waveguide, is etched away according to the preset pattern.

[0054] The photoresist is spin-coated again, followed by ultraviolet lithography, development, etching, and photoresist removal. The ridge waveguide 7, groove 10, shoulder 11, and elliptical deep groove 12 structures are etched according to the preset structural pattern.

[0055] An insulating layer 13 was grown on the prepared structure using PECVD technology. The insulating layer 13 was made of SiO2 and had a thickness of 200 nm.

[0056] After the insulating layer 13 is grown, photoresist is spin-coated on its surface, and ultraviolet lithography, development, etching, and photoresist removal steps are performed to etch away the insulating layer 13 except for the ohmic contact layer 8, leaving a window to expose the ohmic contact layer 8.

[0057] Photoresist is spin-coated onto the surface, followed by ultraviolet lithography and development. The photoresist at the boundary is retained according to the preset structural pattern. A P-side metal layer 9 is deposited on the surface using electron beam evaporation deposition technology. Finally, the photoresist and metal at the boundary are removed using a stripping technique.

[0058] The substrate 1 is thinned and polished on the side away from the P-side metal to reduce its thickness to 100~120μm, and the N-side metal is deposited on the thinned and polished side.

[0059] An elliptical deep-groove narrow-ridge semiconductor laser was fabricated by cleaving, coating, and packaging the wafer.

[0060] In another embodiment, a method for fabricating a conventional slotless ridge waveguide semiconductor laser is provided, the specific process of which is shown below:

[0061] The laser substrate 1 is a GaAs crystal with a crystal orientation of (100) and a substrate thickness of 500 μm.

[0062] A transition layer was grown on substrate 1 using an MOCVD device. The transition layer material was Si-doped GaAs, and the thickness was 200 nm.

[0063] An N-confined layer 2 is grown on the transition layer using an MOCVD device. The material of the N-confined layer 2 is Si-doped AlInP with a doping concentration of 1~4E18 / cm3 and a thickness of 1000nm.

[0064] The N-confinement layer 2 is covered by an N-waveguide layer 3 grown by an MOCVD device. The material is AlGaInP, and the thickness of the N-waveguide 3 is 90nm~120nm. By adjusting the composition of Al, the AlGaInP is distributed in a gradual manner along the direction perpendicular to the growth plane, with a higher Al composition in the direction away from the GaAs substrate.

[0065] An active layer 4 is grown above the N-waveguide layer 3. The active layer 4 has a structure consisting of GaInP, AlGaInP, and GaInP stacked together to form a double quantum hydrazine sandwich structure active layer from bottom to top. The GaInP layer has a thickness of 5 nm, and the AlGaInP layer has a thickness of 10 nm.

[0066] A P-waveguide layer 5 is grown above the active layer 4. The P-waveguide layer 5 is made of AlGaInP and has a thickness of 90nm~120nm. The Al composition in the material exhibits a gradual distribution along the direction perpendicular to the growth plane, with a higher Al composition in the direction away from the GaAs substrate.

[0067] A P-confining layer 6 is grown above the P-waveguide layer 5. The P-confining layer 6 is made of AlInP and has a thickness of 1200 nm. A GaInP blocking layer is grown in the P-confining layer 6, and the blocking layer is located at the bottom of the P-confining layer 6 at a distance of 200 nm. An AlGaInP blocking layer is located on top of the P-confining layer 6, and the blocking layer has a thickness of 60 nm.

[0068] An ohmic contact layer 8 is grown on the P-confined layer 6. The ohmic contact layer is made of highly doped GaAs and has a thickness of 140 nm.

[0069] After the epitaxial wafer is grown, photoresist is spin-coated onto the surface of the ohmic contact layer 8, followed by ultraviolet lithography, development, and etching. In the photoresist removal step, the ohmic contact layer 8, excluding the ridge waveguide, is etched away according to the preset pattern.

[0070] The photoresist is spin-coated again, followed by ultraviolet lithography, development, etching, and photoresist removal. The ridge waveguide 7, groove 10, and shoulder 11 structures are etched according to the preset structural pattern.

[0071] An insulating layer 13 was grown on the prepared structure using PECVD technology. The insulating layer 13 was made of SiO2 and had a thickness of 200 nm.

[0072] After the insulating layer 13 is grown, photoresist is spin-coated on its surface, and ultraviolet lithography, development, etching, and photoresist removal steps are performed to etch away the insulating layer 13 except for the ohmic contact layer 8, leaving a window to expose the ohmic contact layer 8.

[0073] Photoresist is spin-coated on the surface, ultraviolet lithography and development are performed, and the photoresist at the boundary is retained according to the preset structural pattern. A P-side metal layer 9 is deposited on the surface using electron beam evaporation deposition technology. Then, the photoresist and metal at the boundary are removed by peeling technology.

[0074] The substrate 1 is thinned and polished on the side away from the P-side metal to reduce its thickness to 100~120μm, and the N-side metal is deposited on the thinned and polished side.

[0075] A conventional slotless ridge waveguide semiconductor laser was fabricated by cleaving, coating, and packaging the wafer.

[0076] Performance testing

[0077] The performance of the elliptical deep-groove narrow-ridge semiconductor laser prepared in the above embodiments was tested, and the results are as follows: Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown. Among them, Figure 5 This is a schematic diagram of the transmission of the TE0 fundamental mode within the ridge waveguide structure of the elliptical deep groove narrow ridge semiconductor laser. The arrow indicates the misalignment position of the elliptical deep groove 12. Figure 6 This is a schematic diagram of the transmission of the TE1 higher-order mode within the ridge waveguide structure of the elliptical deep-groove narrow-ridge semiconductor laser. The arrow indicates the position of the elliptical deep groove 12. Figure 7 This is the far-field distribution diagram of the optical field in the TE0 fundamental mode. Figure 8 This is the far-field distribution diagram of the optical field in the TE1 higher-order mode.

[0078] Meanwhile, the performance of the conventional slotless ridge waveguide semiconductor laser prepared in the above embodiments was tested, and the results are as follows: Figure 9 , Figure 10 As shown. Among them, Figure 9 This is a schematic diagram illustrating the transmission of the TE0 fundamental mode within the ridge waveguide structure of a conventional slotless ridge waveguide semiconductor laser. Figure 9 This is a schematic diagram showing the transmission of the TE1 higher-order mode within the ridge waveguide structure of a conventional slotless ridge waveguide semiconductor laser.

[0079] from Figure 5 , Figure 6 , Figure 7 and Figure 8 As can be seen, the higher-order modes within the elliptical deep-groove narrow-ridge semiconductor laser exhibit diffraction and mode field redistribution at the elliptical deep-groove 12 position, leading to instability of the higher-order modes during transmission and increasing the loss of higher-order modes within the ridge waveguide, thus achieving the suppression function for higher-order modes. The fundamental mode, however, is less affected at the elliptical deep-groove 12, with minimal loss change, and its transmission direction and distribution remain essentially consistent with the initial state. Combined with the gain selection characteristics of the resonant cavity, this further enhances the gain of the fundamental mode, suppressing higher-order modes and forming a pure fundamental mode far-field beam pattern (e.g., ...). Figure 7 (As shown). This demonstrates that elliptical deep-groove narrow-ridge semiconductor lasers can effectively achieve optical filtering, thereby improving the far-field beam pattern.

[0080] from Figure 9 and Figure 10 As can be seen from the diagram, there is no elliptical deep groove 12 in a conventional slotless ridge waveguide semiconductor laser. Therefore, the propagation of the fundamental mode and higher-order modes in the ridge waveguide is not affected. After laser gain amplification, both the fundamental mode and higher-order modes will form in the far field as shown in the diagram. Figure 7 , Figure 8 The light spots shown, especially the high-order mode far field Figure 8 This will cause interference on both sides of the far-field beam of the fundamental mode, affecting the beam quality of the laser. This indicates that symmetrical ridge semiconductor lasers lack filtering capabilities and cannot achieve beam optimization.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An elliptical deep-groove narrow-ridge semiconductor laser, characterized in that, The structure includes a substrate (1), an N-confinement layer (2), an N-waveguide layer (3), a quantum hydrazine active layer (4), and a P-waveguide layer (5) connected together from bottom to top. The surface of the quantum hydrazine active layer (4) is provided with two shoulders (11), and a ridge waveguide (7) is provided between the two shoulders (11). A groove (10) is formed between the shoulders (11) and the ridge waveguide (7). Elliptical deep grooves (12) are provided on both sides of the ridge waveguide (7). The long arc edge of the elliptical deep groove (12) penetrates the ridge waveguide (7) to form a narrow ridge waveguide. The diameter of the elliptical deep groove (12) is between five and one hundred micrometers, and the depth of the elliptical deep groove (12) is between 0.1 and five micrometers.

2. The elliptical deep-groove narrow-ridge semiconductor laser according to claim 1, characterized in that: The narrowest region of the narrow ridge waveguide is two to thirty micrometers, the long side diameter of the elliptical deep groove (12) is sixty micrometers, the short side diameter is twenty micrometers, and the depth of the elliptical deep groove (12) is one and two micrometers.

3. The elliptical deep-groove narrow-ridge semiconductor laser according to claim 1, characterized in that: The shoulder (11) includes a P-confining layer (6), which is disposed on the P-waveguide layer (5). Two sets of protrusions are integrally formed on the P-confining layer (6), and a rectangular protrusion is integrally formed between the two sets of protrusions. The rectangular protrusion forms a ridge waveguide (7).

4. An elliptical deep-groove narrow-ridge semiconductor laser according to claim 1, characterized in that: The shoulder (11) includes two P-confining layers (6) with a convex cross-section. The quantum hydrazine active layer (4) and the P-waveguide layer (5) are divided into three parts. The two P-confining layers (6) are located above the P-waveguide layers (5) on both sides, and the ridge waveguide (7) is located above the middle P-waveguide layer (5).

5. An elliptical deep-groove narrow-ridge semiconductor laser according to any one of claims 3 or 4, characterized in that: An ohmic contact layer (8) is provided on the top of the ridge waveguide (7); The P-limiting layer (6) is covered with an insulating layer (13), and the insulating layers (13) on both sides are in contact with the sides of the ohmic contact layer (8). The top surfaces of the insulating layer (13) and the ohmic contact layer (8) are covered with a P-side metal layer (9). The P-side metal layer (9) is at least two of titanium, platinum, gold, nickel, germanium, chromium and tin. The thickness of the P-side metal layer (9) is between two hundred nanometers and nine hundred nanometers.

6. An elliptical deep-groove narrow-ridge semiconductor laser according to claim 1, characterized in that: The ridge width of the ridge waveguide (7) ranges from two μm to two hundred and sixty micrometers, and the height of the ridge waveguide (7) and the depth of the groove (10) are between 0.1 and 5 micrometers.

7. An elliptical deep-groove narrow-ridge semiconductor laser according to claim 1, characterized in that: The substrate (1) is made of at least one of GaAs, InP, and Si; The N-confining layer (2) is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the N-confining layer (2) is between one and three micrometers. The N-waveguide layer (3) is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the N-waveguide layer (3) is between 90 and 120 nanometers. The quantum hydrazine active layer (4) is a layered structure formed by GaInP, AlGaInP, and GaInP, and the thickness of the quantum hydrazine active layer (4) is one to forty nanometers. The P-waveguide layer (5) is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the P-waveguide layer (5) is between 90 and 120 nanometers. The P-confining layer (6) is made of at least one of GaAs, GaInP, AlInP, AlGaInP, AlGaAs, AlGaAsP, and InGaAsP, and the thickness of the P-confining layer (6) is one to three micrometers. The insulating layer (13) is made of any one of SiON confinement layer (2), SiN waveguide layer (3), N quantum hydrazine active layer (4), or AlN, and the thickness of the insulating layer (13) is fifty to one thousand nanometers.

8. An elliptical deep-groove narrow-ridge semiconductor laser according to any one of claims 1-7, characterized in that: The cavity length of a single tube of the semiconductor laser is 250 to 11 micrometers, the width is 150 to 450 micrometers, and the thickness is 100 to 300 micrometers.

Images