CN116435868A

CN116435868A - Surface-emitting semiconductor laser chip and surface-emitting external cavity laser system

Info

Publication number: CN116435868A
Application number: CN202310521244.3A
Authority: CN
Inventors: 张星
Original assignee: Jiangsu Changguang Spacetime Optoelectronics Technology Co ltd
Current assignee: Jiangsu Changguang Spacetime Optoelectronics Technology Co ltd
Priority date: 2023-05-10
Filing date: 2023-05-10
Publication date: 2023-07-14

Abstract

The invention 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 device comprises a transverse oscillation assembly, a vertical oscillation assembly, a substrate assembly, a lens assembly and a reflecting mirror assembly, wherein the reflecting mirror assembly is arranged on the upper surface of the substrate assembly, the vertical oscillation assembly and the transverse oscillation assembly are both arranged on the upper surface of the reflecting mirror assembly, the transverse oscillation assembly is arranged on two sides of the vertical oscillation assembly, the lens assembly is arranged on the top end of the vertical oscillation assembly, and the transverse oscillation assembly forms laser through electric injection and pumps the laser into the vertical oscillation assembly to be emitted by the lens assembly. The transverse oscillation component forms laser through electric injection, and the emitted laser directly pumps the active area of the vertical oscillation component and forms vertical oscillation laser. The emission wavelength of the laser can be changed by adjusting the cavity length through the piezoelectric component at the top of the vertical oscillation component.

Description

Surface-emitting semiconductor laser chip and surface-emitting external cavity laser system

Technical Field

The invention relates to the field of laser semiconductors, in particular to a surface-emitting semiconductor laser chip and a surface-emitting external cavity laser system.

Background

Semiconductor lasers are the semiconductor devices which are most rapidly developed and widely used at present, and have irreplaceable importance in the fields of communication, sensing, industrial processing, medical treatment and the like. The surface emitting semiconductor laser has the advantages of vertical light emission, easy integration, low power consumption, circular light spots and the like, and gradually becomes a new hot spot for the development of the field of semiconductor lasers.

The surface-emitting semiconductor laser chip commonly used at present is mainly based on a gallium arsenide (GaAs) material system, the light-emitting wavelength generally covers 600-1200 nm wave band, and photoelectric limitation is formed by means of oxidized aperture. Current is injected into the active region through electrodes on the upper and lower surfaces of the laser to generate stimulated radiation, and the emitted light oscillates in a resonant cavity formed by the upper and lower DBR reflectors, and finally laser is formed. The emission wavelength of the device is determined by the cavity mode formed by the DBR mirror and the active region, and when the current and the temperature are fixed, the output wavelength of the laser is fixed. The output laser spot is generally circular, and the divergence angle is generally 15-20 degrees. For longer light-emitting wave bands, the conventional GaAs material system cannot realize surface-emitting laser due to the limitation of gain materials, and the method widely adopted at present is to adopt an indium phosphide (InP) material system, and because the InP material system lacks a proper oxidation material to form photoelectric limitation, the long-wavelength InP-based-surface-emitting semiconductor laser generally needs to prepare a buried tunnel junction and a secondary epitaxial process to form photoelectric limitation, so that the process preparation difficulty is greatly increased. In addition, the external cavity laser system based on the surface emission gain chip has particularly important application prospect in the fields of sensing, wireless charging and the like. The surface of the traditional surface emitting laser emits light, so that the electrode at one light emitting side can only be an annular electrode, the transverse diffusion distance of current is limited, when the light emitting area is overlarge, the current distribution is not uniform, the center of the light emitting area is not provided with the current distribution, and the light emitting mode of the surface emitting gain chip is influenced, so that the whole external cavity laser system is influenced.

The existing electric pumping surface emitting laser generally has a fixed oscillation cavity length, the cavity length is difficult to adjust, the divergence angle of the emitted laser is basically fixed, and the adjustment is difficult. Meanwhile, the existing electric pump surface emitting laser needs a complex process for realizing laser with a wavelength of 1300-1800 nm.

The existing optical pumping surface emitting lasers all adopt an external light source irradiation mode, the system volume is increased, the frequency of pumping laser passing through an active area is limited, and the laser utilization rate is low.

Disclosure of Invention

The invention provides a surface-emitting semiconductor laser chip and a surface-emitting external cavity laser system, which solve at least one technical problem existing in the prior art.

The technical scheme of the invention is as follows: the surface-emitting semiconductor laser chip comprises a transverse oscillation component, a vertical oscillation component, a substrate component, a lens component and a reflecting mirror component, wherein the reflecting mirror component is arranged on the upper surface of the substrate component, the vertical oscillation component and the transverse oscillation component are both arranged on the upper surface of the reflecting mirror component, the transverse oscillation component is arranged on two sides of the vertical oscillation component, the lens component is arranged on the top end of the vertical oscillation component, and the transverse oscillation component forms laser through electric injection and pumps the laser into the vertical oscillation component, and the laser is emitted by the lens component.

Further, the lateral oscillation assembly includes: the light source comprises an active region, a cladding region, a grating region, a reflecting layer and a first electrode layer, wherein the active region is arranged on the upper surface of the reflecting mirror assembly, the cladding region and the grating region are arranged on the upper surface of the active region, the grating region is located between the cladding region and the vertical oscillation assembly, the emitting layer is arranged on the side surfaces of one sides of the cladding region and the active region, which are away from the vertical oscillation assembly, and the first electrode layer is arranged on the upper surface of the cladding region.

Further, the grating order of the grating area is 1-100, the grating period is 0.1-2 microns, the duty ratio is 10% -90%, and the length is 100-1000 microns.

Further, the vertical oscillation assembly comprises an oscillation table and an active area, the oscillation table is arranged on the upper surface of the active area, and the lens assembly is arranged on the upper surface of the oscillation table.

Further, the upper surface of the oscillating table is provided with a first electrode ring, the upper surface of the first electrode ring is provided with a piezoelectric component, the second electrode ring covers the outer diameter of the piezoelectric component, and the lens component is arranged on the upper surface of the piezoelectric component.

Further, the first electrode ring and the second electrode ring are both connected with square electrodes, an insulating layer is arranged between the second electrode ring and the upper surface of the oscillating table, and the insulating layer surrounds the square electrodes and the first electrode ring.

Further, the piezoelectric assembly includes a piezoelectric ceramic ring.

Further, the active region includes an active layer, a first waveguide layer, and a second waveguide layer, the active layer being disposed between the first waveguide layer and the second waveguide layer.

Further, the substrate assembly includes a second electrode layer and a substrate disposed on an upper surface of the second electrode layer.

Another technical scheme of the invention is as follows: the surface-emitting external cavity laser system comprises any one of the surface-emitting semiconductor laser chips and a reflector, wherein the lens assembly comprises a convex lens group, the convex lens group is positioned above the vertical oscillation assembly of the surface-emitting semiconductor laser chips, the reflector is positioned above the convex lens group, the convex lens group is used for collimating light emitted by the surface-emitting semiconductor laser chips, and the reflector is used for reflecting the collimated light back to the emitting semiconductor laser chips.

The invention has the beneficial effects that: the invention provides a surface emitting semiconductor laser chip, which comprises a transverse oscillation component and a vertical oscillation component, wherein the transverse oscillation component forms laser through electric injection, and the emitted laser directly pumps an active area of the vertical oscillation component and forms vertical oscillation laser. The cavity length is adjusted through the piezoelectric component at the top of the vertical oscillation component, so that the emission wavelength of laser can be changed, and in addition, the lens component can be used for carrying out beam shaping by adopting a circular convex lens, and the divergence angle of the emitted laser can be adjusted. The surface-emitting semiconductor laser chip structure can emit near-red laser light covering the wave band range of 600-1800 nm by adopting different material systems. The invention can form a large light-emitting area by directly pumping the vertical oscillation component in the center through the laser emitted by the transverse oscillation components at the two sides of the chip, and the two gratings have reflection effect on the light emitted into the component, so that the light is continuously reflected between the two gratings until the light is completely absorbed by the active area, and the utilization rate of pumping laser is greatly increased.

Drawings

Fig. 1 is a schematic cross-sectional structure of a surface-emitting semiconductor laser chip of the present invention.

Fig. 2 is a partial enlarged view of fig. 1.

Fig. 3 is a top view of a surface emitting semiconductor laser chip of the present invention.

Fig. 4 is a schematic structural view of a surface-emitting external cavity laser system according to the present invention.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings, in which the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

In an embodiment of the present invention, fig. 1 is a schematic structural diagram provided by a specific structure of a surface-emitting semiconductor laser chip according to the present invention, and as shown in fig. 1, the present invention includes: the device comprises a transverse oscillation assembly, a vertical oscillation assembly, a substrate assembly, a lens assembly 114 and a reflecting mirror assembly 103, wherein the reflecting mirror assembly 103 is arranged on the upper surface of the substrate assembly, the vertical oscillation assembly and the transverse oscillation assembly are both arranged on the upper surface of the reflecting mirror assembly 103, the transverse oscillation assembly is arranged on two sides of the vertical oscillation assembly, the lens assembly 114 is arranged on the top end of the vertical oscillation assembly, and the transverse oscillation assembly forms laser through electric injection and pumps the laser into the vertical oscillation assembly to be emitted by the lens assembly 114. The laser emitted by the transverse oscillation components at two sides of the chip directly pumps the vertical oscillation component in the center, so that a large light-emitting area can be formed. Specifically, the total cavity length of the surface-emitting semiconductor laser chip is 500-5000 microns, the width is 200-800 microns, and the thickness is 100-300 microns. The length of the two lateral oscillating components is 1000-2400 microns, and the length of the central vertical oscillating component is 200-1000 microns.

As shown in fig. 1, the substrate assembly includes a second electrode layer 101 and a substrate 102, where the substrate 102 is disposed on an upper surface of the second electrode layer 101, and the second electrode layer 101 is an N-type electrode, and has a thickness between 200nm and 500 nm, and is made of an alloy material formed by metallic titanium, platinum, gold, nickel, germanium, and the like. The substrate 102 may be an N-type indium phosphide (InP) material.

As shown In fig. 1, the mirror assembly 103 may be an N-type Distributed Bragg Reflector (DBR) mirror, specifically, a periodically grown indium aluminum gallium arsenide/indium aluminum gallium arsenide (inagaas/inagaas) material, each layer of material has an In component of 0.5-0.6 and an al component of 0.05-0.95, and each layer of material has a thickness of a ratio of a quarter of an emitted light wavelength to a refractive index of the material, specifically, a quarter of an emitted light wavelength divided by the refractive index of the material, a log range of a period of 20-40 pairs (inclusive), and a total thickness of 2-5 micrometers (inclusive). The doping agent is Si, and the doping concentration is 1E 16-8E 18/cm ³ 。

As shown in fig. 1, the lateral oscillation assembly includes: an active region, a cladding region 107, a grating region 109, a reflective layer 115 and a first electrode layer 108, wherein the active region is disposed on the upper surface of the mirror 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 disposed between the cladding region 107 and the vertical oscillation assembly, the reflective layer is disposed on the side surfaces of the cladding region 107 and the active region facing away from the vertical oscillation assembly, and the first electrode layer 108 is disposed on the upper surface of the cladding region 107.

Wherein the cladding region 107 is a P-type cladding, and is made of InP material with a thickness of 0.1-3 μm, a dopant of C, and a doping concentration of 1E 18-1E 20/cm ³ 。

The length of the grating region 109 is 100-1000 micrometers, the grating order of the grating region 109 is 1-100, the grating period is 0.1-2 micrometers, the duty ratio is 10% -90%, and the length is 100-1000 micrometers. The grating is prepared by a mature photolithography technique comprising: common lithography, electron beam lithography, holographic lithography.

The reflective layer 115 may be plated on the cleaved surfaces on both sides of the chip, specifically covering the sides of the substrate assembly and mirror assembly 103. In particular, a highly reflective film, which is a commonly used optical film such as silicon oxide, aluminum oxide, or the like, may be used.

The first electrode layer 108 is a P-type electrode, and has a thickness of 200nm to 500 nm, and is made of an alloy material formed by titanium, platinum, gold, nickel, germanium, etc.

The vertical oscillation component comprises an oscillation table 116 and an active area, the oscillation table 116 is arranged on the upper surface of the active area, and the lens component 114 is arranged on the upper surface of the oscillation table 116. Wherein the oscillating table 116 is a P-type cladding layer, and is made of InP material, and has a thickness larger than that of the cladding region 107, a doping agent of C, and a doping concentration of 1E 18-1E 20/cm ³ . On the surface-emitting semiconductor laser chip, the cladding region 107 of the lateral oscillation element on both sides and the oscillation stage 116 of the vertical oscillation element are formed by etching a part of the P-type cladding.

The active areas of the vertical oscillation component and the lateral oscillation component have the same structure and are integrally formed, and specifically comprise an active layer 105, a first waveguide layer 104 and a second waveguide layer 106, wherein the active layer 105 is arranged 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.

The first waveguide layer 104 is an N-type waveguide, and may be made of InAlGaAs (InAlGaAs) material, wherein the In component is 0.5-0.6, the Al component is 0.05-0.95, the thickness is 0.1-10 microns, the dopant is Si, and the doping concentration is 1E 16-8E 18/cm ³ 。

The active layer 105 is non-actively doped, is of a barrier/quantum well/barrier structure, and is made of InAlGaAs/InAlGaAs/AlGaAlGaAs (InAlGaAs/InAlGaAs/AlGaAs), wherein In component is 0.4-0.8, al component is 0-0.5, P component is 0-0.2, the barrier thickness is 1-200 nanometers, the quantum well thickness is 1-20 nanometers, and the light-emitting wave band is 1200-1800 nanometers.

The second waveguide layer 106 is a P-type waveguide, and may be made of InAlGaAs material, wherein the In component is 0.5-0.6, the Al component is 0.05-0.7, the thickness is 0.1-10 microns, the dopant is C, and the doping concentration is 1E 16-8E 18/cm ³ 。

As shown in fig. 2 and 3, the upper surface of the oscillating table 116 is provided with a first electrode ring 111, the upper surface of the first electrode ring 111 is provided with a piezoelectric assembly 112, the second electrode ring 113 covers the outer diameter of the piezoelectric assembly 112, and the lens assembly 114 is disposed on the upper surface of the piezoelectric assembly 112. The first electrode ring 111 is an N-type electrode ring, the piezoelectric element 112 may be a piezoelectric ceramic ring, and the second electrode ring 113 may be a P-type electrode ring. The first electrode ring 111 and the second electrode ring 113 are both connected with square electrodes, specifically, as shown in fig. 3, 201 in the drawing refers to square electrodes connected with an N-type electrode ring (first electrode ring), and 202 in the drawing refers to square electrodes connected with a 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 oscillating table 116, and the insulating layer 110 surrounds the square electrode and the first electrode ring 111. Wherein the insulating layer 110 may be SiO ₂ Or Si (or) ₃ N ₄ The thickness is 50-1000 nanometers. The lens assembly 114 may employ a convex lens, an upper surface of which is coated with an optical film having a certain reflectivity.

The inner diameter of the N-type electrode ring is 10-800 micrometers, the width of the N-type electrode ring is 20-100 micrometers, the N-type electrode ring is connected with a square electrode, the component of the square electrode is the same as that of the N-type electrode ring, the square electrode is positioned on the insulating layer 110, the length of the square electrode is 100-800 micrometers, and the width of the square electrode is 50-100 micrometers.

The inner diameter of the piezoelectric ceramic ring is 10-800 micrometers, the width is 20-100 micrometers, and the thickness is 500-5000 micrometers.

The upper surface of the piezoelectric ceramic ring is provided with a P-type electrode ring, the P-type electrode ring partially covers the outer diameter of the piezoelectric ceramic ring, the inner diameter of the P-type electrode ring is 10-800 microns, the width of the P-type electrode ring is 20-100 microns, the P-type electrode ring is connected with a square electrode, the components of the square electrode are the same as the P-type electrode ring, the square electrode is positioned on the insulating layer 110, and the square electrode is 100-800 microns long and 50-100 microns wide.

The upper surface of the piezoelectric ceramic ring is fixed with a convex lens by adopting optical curing glue, the convex lens is a mature commodity, an optical film is plated on the upper surface of the convex lens, the diameter of the convex lens is 10-800 microns, and the curvature radius of the convex lens and the reflectivity of the optical film can be customized according to specific requirements.

An N-type electrode ring is formed on the table top of the vertical oscillating table 116 in the central area of the chip through a process, a piezoelectric ceramic ring is welded on the N-type electrode ring, an insulating silicon oxide material is covered outside the N-type electrode ring, and a circular convex lens is fixed on the annular piezoelectric ceramic by optical cement. The outer ring part of the upper surface of the annular piezoelectric ceramic is covered by the P-type electrode ring.

As shown in fig. 4, another technical solution of the present invention is as follows: a surface-emitting external cavity laser system comprising any one of the above-mentioned surface-emitting semiconductor laser chips and a reflecting mirror 301, wherein the lens assembly 114 comprises a convex lens group located above the vertical oscillation assembly of the surface-emitting semiconductor laser chip, the reflecting mirror 301 is located above the convex lens group, the convex lens group is used for collimating light emitted from the surface-emitting semiconductor laser chip, and the reflecting mirror is used for reflecting the collimated light back to the emitting semiconductor laser chip. It should be noted that in the figure, the lines between the mirror, the two convex lenses and the vertical oscillating element represent the propagating light rays.

The convex lens group comprises two convex lenses with the same size, the convex lenses close to the surface emission semiconductor laser chip are used for collimating light emitted by the surface emission gain chip, the collimated light is transmitted to the second convex lens, the distance between the two convex lenses is 0.1-10 m, the light is focused after passing through the second convex lens and is reflected back to the surface emission gain chip by the reflector, external cavity light oscillation is formed, and finally laser is emitted from the reflector. The convex lens and the reflecting mirror are mature commodity, and the size and the surface coating can be customized according to the requirements.

Finally, it should be noted that the above-mentioned embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications and equivalents may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention, and all such modifications and equivalents are intended to be encompassed in the scope of the claims of the present invention.

Claims

1. The surface-emitting semiconductor laser chip is characterized by comprising a transverse oscillation component, a vertical oscillation component, a substrate component, a lens component (114) and a reflecting mirror component (103), wherein the reflecting mirror component (103) is arranged on the upper surface of the substrate component, the vertical oscillation component and the transverse oscillation component are both arranged on the upper surface of the reflecting mirror component (103), the transverse oscillation component is arranged on two sides of the vertical oscillation component, the lens component (114) is arranged on the top end of the vertical oscillation component, and the transverse oscillation component forms laser through electric injection and pumps the laser into the vertical oscillation component to be emitted by the lens component (114).

2. The surface-emitting semiconductor laser chip of claim 1, wherein the lateral oscillation assembly comprises: active region, cladding region (107), grating region (109), reflection stratum (115) and first electrode layer (108), the active region sets up the upper surface of reflector subassembly (103), cladding region (107) and grating region (109) set up the upper surface of active region, grating region (109) are located between cladding region (107) and the vertical oscillation subassembly, the emitting layer sets up cladding region (107) and active region deviate from the lateral surface of one side of vertical oscillation subassembly, first electrode layer (108) set up the upper surface of cladding region (107).

3. The surface-emitting semiconductor laser chip according to claim 2, wherein the grating order of the grating region (109) is 1 to 100, the grating period is 0.1 to 2 μm, the duty ratio is 10% to 90%, and the length is 100 to 1000 μm.

4. The surface-emitting semiconductor laser chip according to claim 1, wherein the vertical oscillation module includes an oscillation stage (116) and an active region, the oscillation stage (116) is disposed on an upper surface of the active region, and the lens module (114) is disposed on an upper surface of the oscillation stage (116).

5. The surface-emitting semiconductor laser chip according to claim 4, wherein the upper surface of the oscillating table (116) is provided with a first electrode ring (111), the upper surface of the first electrode ring (111) is provided with a piezoelectric element (112), the second electrode ring (113) covers the outer diameter of the piezoelectric element (112), and the lens element (114) is provided on the upper surface of the piezoelectric element (112).

6. The surface-emitting semiconductor laser chip according to claim 5, wherein the first electrode ring (111) and the second electrode ring (113) are each connected with a square electrode, an insulating layer (110) is provided between the second electrode ring (113) and an upper surface of the oscillating table (116), and the insulating layer (110) surrounds the square electrode and the first electrode ring (111).

7. The surface emitting semiconductor laser chip of claim 5, wherein the piezoelectric component (112) comprises a piezoceramic ring.

8. The surface-emitting semiconductor laser chip according to any one of claims 2 to 7, wherein the active region includes an active layer (105), a first waveguide layer (104) and a second waveguide layer (106), the active layer (105) being disposed between the first waveguide layer (104) and the second waveguide layer (106).

9. The surface emitting semiconductor laser chip according to claim 1, wherein the substrate assembly comprises a second electrode layer (101) and a substrate (102), the substrate (102) being disposed on an upper surface of the second electrode layer (101).

10. A surface-emitting external cavity laser system comprising the surface-emitting semiconductor laser chip according to any one of claims 1 to 4 and a reflecting mirror (301), wherein the lens assembly (114) comprises a convex lens group, the convex lens group is located above the vertical oscillation assembly of the surface-emitting semiconductor laser chip, the reflecting mirror (301) is located above the convex lens group, the convex lens group is used for collimating light emitted by the surface-emitting semiconductor laser chip, and the reflecting mirror (301) is used for reflecting the collimated light back to the surface-emitting semiconductor laser chip.