A surface emitting semiconductor laser chip and a surface emitting external cavity laser system

Abstract

The application relates to the field of laser semiconductors, in particular to a surface-emitting semiconductor laser chip and a surface-emitting external cavity laser system. The surface-emitting semiconductor laser chip comprises a transverse oscillation assembly, a vertical oscillation assembly, a substrate assembly, a lens assembly and a mirror assembly. The mirror assembly is arranged on the upper surface of the substrate assembly, the vertical oscillation assembly and the transverse oscillation assembly are arranged on the upper surface of the mirror assembly, the transverse oscillation assembly is arranged on the two sides of the vertical oscillation assembly, the lens assembly is mounted on the top end of the vertical oscillation assembly, the transverse oscillation assembly forms laser by electric injection and pumps the laser into the vertical oscillation assembly, and the laser is emitted by the lens assembly. The transverse oscillation assembly of the application forms laser by electric injection, the emitted laser directly pumps the active region of the vertical oscillation assembly and forms vertical oscillation laser. The cavity length is adjusted by the piezoelectric assembly on the top of the vertical oscillation assembly, and the emission wavelength of the laser can be changed.

Description

Technical Field

[0001] This invention relates to the field of laser semiconductors, and more particularly to a surface-emitting semiconductor laser chip and a surface-emitting external cavity laser system. Background Technology

[0002] Semiconductor lasers are currently the fastest-growing and most widely used semiconductor devices, playing an irreplaceable role in fields such as communication, sensing, industrial processing, and medicine. Surface-emitting semiconductor lasers, with their advantages such as vertical emission, ease of integration, low power consumption, and circular beam patterns, are gradually becoming a new hotspot in the field of semiconductor lasers.

[0003] Currently, commonly used surface-emitting semiconductor laser chips are mainly based on gallium arsenide (GaAs) materials, with emission wavelengths typically covering the 600-1200 nm band. Photoelectric confinement relies on oxide apertures. Current is injected into the active region through electrodes on the upper and lower surfaces of the laser, generating stimulated emission. The emitted light oscillates within a resonant cavity formed by upper and lower DBR mirrors, ultimately forming a laser beam. The emission wavelength of the device is determined by the cavity mode formed by the DBR mirrors and the active region; when the current and temperature are fixed, the output wavelength of the laser is fixed. The output laser spot is generally circular, with a divergence angle typically between 15 and 20°. For longer emission bands, traditional GaAs materials cannot achieve surface-emitting lasers due to limitations in gain materials. Currently, the widely used method is to employ indium phosphide (InP) materials. However, because InP lacks suitable oxide materials for photoelectric confinement, long-wavelength InP-based surface-emitting semiconductor lasers generally require the fabrication of buried tunnel junctions and secondary epitaxial processes to achieve photoelectric confinement, significantly increasing the fabrication complexity. Furthermore, external cavity laser systems based on surface-emitting gain chips have significant application prospects in fields such as sensing and wireless charging. However, due to the surface emission characteristics of traditional surface-emitting lasers, the electrode on the emission side can only be a ring electrode, resulting in a limited lateral current diffusion distance. When the emitting area is too large, the uneven current distribution leads to a lack of current distribution in the center of the emitting area, affecting the emission mode of the surface-emitting gain chip and consequently the entire external cavity laser system.

[0004] Existing electrically pumped surface-emitting lasers (ESPs) generally have a fixed cavity length, making cavity length adjustment difficult. Their emitted laser divergence angle is also essentially fixed and difficult to adjust. Furthermore, achieving long-wavelength lasers (1300–1800 nm) using existing ESPs requires complex manufacturing processes.

[0005] Existing optically pumped surface-emitting lasers all use external light sources for illumination, which increases the system size and limits the number of times the pump laser passes through the active region, resulting in low laser utilization. Summary of the Invention

[0006] This invention provides a surface-emitting semiconductor laser chip and a surface-emitting external cavity laser system, which solves at least one technical problem existing in the prior art.

[0007] One technical solution of the present invention is as follows: a surface-emitting semiconductor laser chip includes a lateral oscillation component, a vertical oscillation component, a substrate component, a lens component, and a mirror component. The mirror component is disposed on the upper surface of the substrate component. Both the vertical oscillation component and the lateral oscillation component are disposed on the upper surface of the mirror component. The lateral oscillation component is disposed on both sides of the vertical oscillation component. The lens component is mounted on the top of the vertical oscillation component. The lateral oscillation component generates laser light through electrical injection and pumps the laser light into the vertical oscillation component, where it is emitted by the lens component.

[0008] Furthermore, the lateral oscillation component includes: an active region, a cladding region, a grating region, a reflective layer, and a first electrode layer. The active region is disposed on the upper surface of the mirror component. The cladding region and the grating region are disposed on the upper surface of the active region. The grating region is located between the cladding region and the vertical oscillation component. The reflective layer is disposed on the side surface of the cladding region and the active region facing away from the vertical oscillation component. The first electrode layer is disposed on the upper surface of the cladding region.

[0009] Furthermore, the grating order of the grating region is 1 to 100, the grating period is 0.1 to 2 micrometers, the duty cycle is 10% to 90%, and the length is 100 to 1000 micrometers.

[0010] Furthermore, the vertical oscillation assembly includes an oscillation stage and an active region, the oscillation stage being disposed on the upper surface of the active region, and the lens assembly being disposed on the upper surface of the oscillation stage.

[0011] Furthermore, a first electrode ring is provided on the upper surface of the oscillation stage, a piezoelectric component is provided on the upper surface of the first electrode ring, a second electrode ring covers the outer diameter of the piezoelectric component, and the lens assembly is provided on the upper surface of the piezoelectric component.

[0012] Furthermore, both the first electrode ring and the second electrode ring are connected to square electrodes, and an insulating layer is provided between the second electrode ring and the upper surface of the oscillation stage, the insulating layer surrounding the square electrodes and the first electrode ring.

[0013] Furthermore, the piezoelectric component includes a piezoelectric ceramic ring.

[0014] Furthermore, the active region includes an active layer, a first waveguide layer, and a second waveguide layer, with the active layer disposed between the first waveguide layer and the second waveguide layer.

[0015] Furthermore, the substrate assembly includes a second electrode layer and a substrate, the substrate being disposed on the upper surface of the second electrode layer.

[0016] Another technical solution of the present invention: a surface-emitting external cavity laser system, comprising any of the surface-emitting semiconductor laser chips and a reflector as described above, wherein the lens assembly includes a convex lens group, the convex lens group being located above the vertical oscillation component of the surface-emitting semiconductor laser chip, the reflector being located above the convex lens group, the convex lens group being used to collimate the light emitted by the surface-emitting semiconductor laser chip, and the reflector being used to reflect the collimated light back to the surface-emitting semiconductor laser chip.

[0017] The beneficial effects of this invention are as follows: This invention provides a surface-emitting semiconductor laser chip, including a transverse oscillation component and a vertical oscillation component. The transverse oscillation component generates laser light through electrical injection, and the emitted laser light directly pumps the active region of the vertical oscillation component to form a vertically oscillating laser. The emission wavelength of the laser can be changed by adjusting the cavity length through a piezoelectric component at the top of the vertical oscillation component. Furthermore, the lens component, using a circular convex lens, can perform beam shaping and adjust the divergence angle of the emitted laser light. Using different material systems, the surface-emitting semiconductor laser chip structure of this invention can emit near-infrared laser light covering the 600-1800nm ​​wavelength range. This invention allows the laser light emitted from the transverse oscillation components on both sides of the chip to directly pump the central vertical oscillation component, forming a large emitting area. The two gratings of this invention reflect the light incident on the component, causing the light to be continuously reflected between the two gratings until it is completely absorbed by the active region, greatly increasing the utilization rate of the pump laser. Attached Figure Description

[0018] Figure 1 This is a cross-sectional structural diagram of a surface-emitting semiconductor laser chip according to the present invention.

[0019] Figure 2 yes Figure 1 A magnified view of a portion of the image.

[0020] Figure 3 This is a top view of a surface-emitting semiconductor laser chip according to the present invention.

[0021] Figure 4 This is a schematic diagram of the structure of a surface-emitting external cavity laser system according to the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. The described embodiments are merely 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 should fall within the scope of protection of the present invention.

[0023] In an embodiment of the present invention, Figure 1 This is a structural schematic diagram provided based on the specific structure of a surface-emitting semiconductor laser chip, as shown below. Figure 1 As shown, the present invention includes: a lateral oscillation component, a vertical oscillation component, a substrate component, a lens component 114, and a reflector component 103. The reflector component 103 is disposed on the upper surface of the substrate component. Both the vertical and lateral oscillation components are disposed on the upper surface of the reflector component 103. The lateral oscillation components are disposed on both sides of the vertical oscillation component. The lens component 114 is mounted on the top of the vertical oscillation component. The lateral oscillation components generate laser light through electrical injection and pump the laser light into the vertical oscillation component, which is then emitted by the lens component 114. This emission, where the laser light emitted by the lateral oscillation components on both sides of the chip directly pumps the central vertical oscillation component, can form a large light-emitting area. Specifically, the total cavity length of the surface-emitting semiconductor laser chip is 500 micrometers to 5000 micrometers, the width is 200 micrometers to 800 micrometers, and the thickness is 100 micrometers to 300 micrometers. The length of the lateral oscillation components on both sides is 1000 micrometers to 2400 micrometers, and the length of the central vertical oscillation component is 200 micrometers to 1000 micrometers.

[0024] like Figure 1 As shown, the substrate assembly includes a second electrode layer 101 and a substrate 102. The substrate 102 is disposed on the upper surface of the second electrode layer 101. The second electrode layer 101 is an N-type electrode with a thickness between 200 nanometers and 500 nanometers, and is made of an alloy material formed from metallic titanium, platinum, gold, nickel, germanium, etc. The substrate 102 can be made of N-type indium phosphide (InP) material.

[0025] like Figure 1As shown, the reflector assembly 103 can be an N-type distributed Bragg reflector (DBR), specifically a periodically grown indium aluminum gallium arsenide / indium aluminum gallium arsenide (InAlGaAs / InAlGaAs) material. Each layer has an In composition of 0.5-0.6 and an Al composition of 0.05-0.95. The thickness of each layer is the ratio of one-quarter of the emitted light wavelength to the material's refractive index, specifically one-quarter of the emitted light wavelength divided by the material's refractive index. The number of periodic logarithmic pairs ranges from 20 to 40 (including endpoints), and the total thickness ranges from 2 to 5 micrometers (including endpoints). The dopant is Si, with a doping concentration of 1E16-8E18 / cm². 3 .

[0026] like Figure 1 As shown, the transverse oscillation assembly includes: an active region, a cladding region 107, a grating region 109, a reflective layer 115, and a first electrode layer 108. The active region is disposed on the upper surface of the reflector assembly 103. The cladding region 107 and the grating region 109 are disposed on the upper surface of the active region. The grating region 109 is located between the cladding region 107 and the vertical oscillation assembly. The reflective layer is disposed on the side surface of the cladding region 107 and the active region facing away from the vertical oscillation assembly. The first electrode layer 108 is disposed on the upper surface of the cladding region 107.

[0027] Among them, the cladding region 107 is a P-type cladding, specifically made of InP material with a thickness of 0.1 μm to 3 μm, and the dopant is C with a doping concentration of 1E18 to 1E20 / cm. 3 .

[0028] The length of the grating region 109 is between 100 micrometers and 1000 micrometers. The grating order of the grating region 109 is 1 to 100, the grating period is 0.1 to 2 micrometers, the duty cycle is 10% to 90%, and the length is between 100 and 1000 micrometers. The grating is fabricated using mature photolithography techniques, including: conventional photolithography, electron beam lithography, and holographic lithography.

[0029] The reflective layer 115 can be deposited on the cleaved surfaces on both sides of the chip, specifically covering the sides of the substrate assembly and the mirror assembly 103. A high-reflectivity thin film can be used, such as commonly used optical thin films like silicon oxide or aluminum oxide.

[0030] The first electrode layer 108 is a P-type electrode with a thickness between 200 nanometers and 500 nanometers, and the material is an alloy material formed from metals such as titanium, platinum, gold, nickel, and germanium.

[0031] The vertical oscillation assembly includes an oscillation stage 116 and an active region. The oscillation stage 116 is disposed on the upper surface of the active region, and the lens assembly 114 is disposed on the upper surface of the oscillation stage 116. The oscillation stage 116 has a P-type cladding, specifically made of InP material, with a thickness greater than that of the cladding region 107 mm. The dopant is C, and the doping concentration is 1E18~1E20 / cm³. 3 On a surface-emitting semiconductor laser chip, the cladding region 107 of the lateral oscillation component and the oscillation stage 116 of the vertical oscillation component are formed by etching a portion of the P-type cladding.

[0032] The active regions of the vertical oscillation component and the lateral oscillation component have identical structures and are integrally formed, specifically including an active layer 105, a first waveguide layer 104, and a second waveguide layer 106, with the active layer 105 disposed between the first waveguide layer 104 and the second waveguide layer 106. Specifically, the active layer 105 is disposed on the upper surface of the first waveguide layer 104, and the second waveguide layer 106 is disposed on the upper surface of the active layer 105.

[0033] The first waveguide layer 104 is an N-type waveguide, which can be made of indium aluminum gallium arsenide (InAlGaAs) material, with an In composition of 0.5~0.6 and an Al composition of 0.05~0.95, a thickness of 0.1 μm~10 μm, and Si as the dopant with a doping concentration of 1E16~8E18 / cm. 3 .

[0034] The active layer 105 is non-actively doped and has a barrier / quantum well / barrier structure. The material is indium aluminum gallium arsenide / indium aluminum gallium arsenide / aluminum gallium arsenide (InAlGaAs / InAlGaAs / AlGaAs), with an In composition of 0.4~0.8, an Al composition of 0~0.5, a P composition of 0~0.2, a barrier thickness of 1 nm~200 nm, a quantum well thickness of 1 nm~20 nm, and an emission wavelength of 1200 nm~1800 nm.

[0035] The second waveguide layer 106 is a P-type waveguide, which can be made of InAlGaAs material with an In composition of 0.5~0.6 and an Al composition of 0.05~0.7, a thickness of 0.1 μm~10 μm, and C as the dopant with a doping concentration of 1E16~8E18 / cm. 3 .

[0036] like Figure 2 and Figure 3As shown, a first electrode ring 111 is disposed on the upper surface of the oscillation stage 116, a piezoelectric component 112 is disposed on the upper surface of the first electrode ring 111, a second electrode ring 113 covers the outer diameter of the piezoelectric component 112, and a lens assembly 114 is disposed on the upper surface of the piezoelectric component 112. The first electrode ring 111 is an N-type electrode ring, the piezoelectric component 112 can be a piezoelectric ceramic ring, and the second electrode ring 113 can be a P-type electrode ring. Both the first electrode ring 111 and the second electrode ring 113 are connected to square electrodes, specifically as shown below. Figure 3 As shown in the figure, 201 refers to the square electrode connected to the N-type electrode ring (first electrode ring), and 202 refers to the square electrode connected to the P-type electrode ring (second electrode ring). An insulating layer 110 is disposed between the second electrode ring 113 and the upper surface of the oscillation stage 116, the insulating layer 110 surrounding the square electrode and the first electrode ring 111. The insulating layer 110 can be made of SiO2 or Si3N4, with a thickness of 50 nm to 1000 nm. The lens assembly 114 can be a convex lens, the upper surface of which is coated with an optical thin film of a certain reflectivity.

[0037] The inner diameter of the N-type electrode ring is 10 micrometers to 800 micrometers, and the width is 20 micrometers to 100 micrometers. The square electrode connected to the N-type electrode ring has the same composition as the N-type electrode ring and is located on the insulating layer 110 material. The square electrode has a length of 100 micrometers to 800 micrometers and a width of 50 micrometers to 100 micrometers.

[0038] The piezoelectric ceramic ring has an inner diameter of 10 micrometers to 800 micrometers, a width of 20 micrometers to 100 micrometers, and a thickness of 500 micrometers to 5000 micrometers.

[0039] The upper surface of the piezoelectric ceramic ring is a P-type electrode ring, which partially covers the outer diameter of the piezoelectric ceramic ring. The inner diameter of the P-type electrode ring is 10 micrometers to 800 micrometers, and the width is 20 micrometers to 100 micrometers. A square electrode with the same composition as the P-type electrode ring is connected to the P-type electrode ring and is located on the insulating layer 110 material. The square electrode is 100 micrometers to 800 micrometers long and 50 micrometers to 100 micrometers wide.

[0040] A convex lens is fixed on the upper surface of a piezoelectric ceramic ring using optically cured adhesive. The convex lens is a commercially available product. The upper surface of the convex lens is coated with an optical film. The diameter of the convex lens is 10 micrometers to 800 micrometers. The radius of curvature of the convex lens and the reflectivity of the optical film can be customized according to specific requirements.

[0041] On the platform of the vertical oscillation stage 116 in the central region of the chip, an N-type electrode ring is formed by a process. A piezoelectric ceramic ring is welded onto the N-type electrode ring. An insulating silicon oxide material is applied to the outside of the N-type electrode ring. A circular convex lens is fixed to the annular piezoelectric ceramic using optical adhesive. The outer ring portion of the upper surface of the annular piezoelectric ceramic is covered by a P-type electrode ring.

[0042] like Figure 4 As shown, another technical solution of the present invention is as follows: a surface-emitting external cavity laser system, comprising any of the surface-emitting semiconductor laser chips described above and a reflector 301, wherein the lens assembly 114 includes a convex lens group, the convex lens group being located above the vertical oscillation component of the surface-emitting semiconductor laser chip, and the reflector 301 being located above the convex lens group. The convex lens group is used to collimate the light emitted by the surface-emitting semiconductor laser chip, and the reflector is used to reflect the collimated light back to the surface-emitting semiconductor laser chip. It should be noted that in the figure, the lines between the reflector, the two convex lenses, and the vertical oscillation component represent propagating light rays.

[0043] The convex lens assembly includes two identical convex lenses. The convex lens closest to the surface-emitting semiconductor laser chip collimates the light emitted from the surface-emitting gain chip. The collimated light is then directed to the second convex lens. The distance between the two lenses is 0.1 meters to 10 meters. After passing through the second convex lens, the light is focused and reflected back to the surface-emitting gain chip by a mirror, forming external cavity optical oscillations. Ultimately, the laser light is emitted from the mirror. Both the convex lens and the mirror are commercially available products, and their dimensions and surface coatings can be customized as needed.

[0044] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A surface-emitting semiconductor laser chip, characterized in that, The system includes a transverse oscillation assembly, a vertical oscillation assembly, a substrate assembly, a lens assembly (114), and a mirror assembly (103). The mirror assembly (103) is disposed on the upper surface of the substrate assembly. Both the vertical oscillation assembly and the transverse oscillation assembly are disposed on the upper surface of the mirror assembly (103). The transverse oscillation assembly is disposed on both sides of the vertical oscillation assembly. The lens assembly (114) is mounted on the top of the vertical oscillation assembly. The transverse oscillation assembly generates laser light through electrical injection and pumps the laser light into the vertical oscillation assembly, which is then emitted by the lens assembly (114). The transverse oscillation component includes: an active region, a cladding region (107), a grating region (109), a reflective layer (115), and a first electrode layer (108). The active region is disposed on the upper surface of the reflector component (103). The cladding region (107) and the grating region (109) are disposed on the upper surface of the active region. The grating region (109) is located between the cladding region (107) and the vertical oscillation component. The reflective layer (115) is disposed on the side surface of the cladding region (107) and the active region away from the vertical oscillation component. The first electrode layer (108) is disposed on the upper surface of the cladding region (107).

2. The surface-emitting semiconductor laser chip as described in claim 1, characterized in that, The grating order of the grating region (109) is 1 to 100, the grating period is 0.1 to 2 micrometers, the duty cycle is 10% to 90%, and the length is 100 to 1000 micrometers.

3. The surface-emitting semiconductor laser chip as described in claim 1, characterized in that, The vertical oscillation assembly includes an oscillation stage (116) and an active region. The oscillation stage (116) is disposed on the upper surface of the active region, and the lens assembly (114) is disposed on the upper surface of the oscillation stage (116).

4. The surface-emitting semiconductor laser chip as described in claim 3, characterized in that, The upper surface of the oscillation stage (116) is provided with a first electrode ring (111), the upper surface of the first electrode ring (111) is provided with a piezoelectric component (112), the second electrode ring (113) covers the outer diameter of the piezoelectric component (112), and the lens assembly (114) is provided on the upper surface of the piezoelectric component (112).

5. The surface-emitting semiconductor laser chip as described in claim 4, characterized in that, The first electrode ring (111) and the second electrode ring (113) are both connected to square electrodes. An insulating layer (110) is provided between the second electrode ring (113) and the upper surface of the oscillation table (116). The insulating layer (110) surrounds the square electrode and the first electrode ring (111).

6. The surface-emitting semiconductor laser chip as described in claim 4, characterized in that, The piezoelectric component (112) includes a piezoelectric ceramic ring.

7. The surface-emitting semiconductor laser chip as described in any one of claims 1 to 6, characterized in that, The active region includes an active layer (105), a first waveguide layer (104), and a second waveguide layer (106), with the active layer (105) disposed between the first waveguide layer (104) and the second waveguide layer (106).

8. The surface-emitting semiconductor laser chip as described in claim 1, characterized in that, The substrate assembly includes a second electrode layer (101) and a substrate (102), wherein the substrate (102) is disposed on the upper surface of the second electrode layer (101).

9. A surface-emitting external cavity laser system, characterized in that, The device includes a surface-emitting semiconductor laser chip as described in any one of claims 1 to 3 and a reflector (301), wherein the lens assembly (114) includes a convex lens group located above the vertical oscillation assembly of the surface-emitting semiconductor laser chip, the reflector (301) is located above the convex lens group, the convex lens group is used to collimate the light emitted by the surface-emitting semiconductor laser chip, and the reflector (301) is used to reflect the collimated light back to the surface-emitting semiconductor laser chip.

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