Laser chip with polarization selection characteristic

Abstract

The invention provides a laser chip with a polarization selection characteristic, a polarization type heat dissipation window sheet is bonded outside a physicochemical protection layer of the laser chip, and an included angle between a bonding edge and a Brewster edge is set to ensure that an incident angle is equal to a Brewster angle when laser in a resonant cavity is incident on the Brewster edge, so that the polarization selection characteristic of the laser chip is improved. Therefore, all the s polarization states in the laser beam are reflected and escape out of the resonant cavity, only the p polarization state of the laser forming the resonance is left, and the output laser is ensured to be linearly polarized p polarized light. And secondly, under the condition that other special polarization elements do not need to be additionally inserted into the resonant cavity, linear polarization laser output can be obtained, so that other elements for selecting polarization of the laser can be omitted, and the intra-cavity loss of the laser is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of laser chips, and particularly to a laser chip with polarization selection characteristics. Background Art

[0002] Polarization, as a descriptive quantity in an independent dimension of light, has a very important impact on the understanding and application of light. In many practical applications of lasers, linearly polarized laser beams are required. For example, in the non-linear frequency conversion of lasers, in order to obtain a high non-linear frequency conversion efficiency, the incident fundamental wave laser needs to achieve phase matching in the non-linear crystal. This phase matching includes not only energy conservation but also momentum conservation, that is, the incident light needs to satisfy a specific polarization state. A simple example is that when using an LBO crystal for laser frequency doubling, if type-I phase matching is adopted, the incident light needs to be the O light, that is, linearly polarized light. In addition, in many applications that require the control and detection of the polarization state of lasers, linearly polarized light is also one of the indispensable conditions. For example, in the electro-optic modulation process used in laser communication, the electric field in the electro-optic crystal is used to change the polarization state of the laser, and in the subsequent detection process, the polarization state of the laser is also required, so it requires that the input laser must be linearly polarized light. There are also many other engineering applications such as polarization imaging, polarization navigation, polarized photography, liquid crystal display, and stereoscopic movies, all of which require the light to be linearly polarized.

[0003] Since most light sources emit non-polarized light, including the laser generated from a laser, most of them are also non-polarized light. Therefore, in the laser technology of actual engineering applications, special polarization elements are generally inserted into the laser resonator, such as dichroic polarizers, polarization beam splitters, Brewster polarizers, etc., to make the output laser become linearly polarized light.

[0004] However, these additional inserted elements will bring a considerable amount of intracavity loss of the laser resonator, thereby increasing the threshold of the laser, reducing the efficiency of the laser, increasing the power consumption of the laser, and weakening the output power of the laser. In addition, the insertion of many additional elements also makes the structure of the laser more complex, increases the adjustment difficulty, and the stability and reliability of the laser are sacrificed to varying degrees, greatly limiting the application of the laser in some engineering scenarios with relatively strict requirements. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a laser chip with polarization selection characteristics to solve the technical problems that in the prior art, the insertion elements will bring a considerable amount of intracavity loss of the laser resonator, resulting in an increase in the threshold of the laser, a decrease in the efficiency of the laser, an increase in the power consumption of the laser, and a weakening of the output power of the laser. It also makes the structure of the laser complex, increases the adjustment difficulty, and sacrifices the stability and reliability of the laser to varying degrees.

[0006] The present invention provides a laser chip with polarization selection characteristics, comprising:

[0007] A chip epitaxial growth substrate, a distributed multi-layer high reflector, a laser gain region, a carrier diffusion barrier layer, a physical and chemical protection layer, and a polarization type heat dissipation window sheet connected in sequence, and a laser coupling output mirror provided at one end of the polarization type heat dissipation window sheet far from the physical and chemical protection layer;

[0008] The cross-section of the polarization type heat dissipation window sheet is a right triangle, and any right side of the polarization type heat dissipation window sheet is bonded to the physical and chemical protection layer through a bonding interface, and the included angle between any bonded right side and its opposite Brewster side is 68°.

[0009] Optionally, the chip epitaxial growth substrate includes:

[0010] It is made of an intrinsic semiconductor or a compound semiconductor material, and the lattice constant of the chip epitaxial growth substrate matches the lattice constants of the materials used for the distributed multi-layer high reflector, the laser gain region, the carrier diffusion barrier layer, the physical and chemical protection layer, the polarization type heat dissipation window sheet, and the laser coupling output mirror.

[0011] Optionally, the distributed multi-layer high reflector includes:

[0012] It is composed of alternating high refractive index material layers and low refractive index material layers, and the optical thickness of each high refractive index material layer and low refractive index material layer is equal to one quarter of the laser wavelength emitted by the laser chip, and both the high refractive index material layers and the low refractive index material layers are made of intrinsic semiconductor or compound semiconductor materials.

[0013] Optionally, the laser gain region includes:

[0014] It is composed of alternating pump light absorption layers and laser emission layers, and the sum of the thicknesses of each pump light absorption layer and laser emission layer is equal to one half of the laser wavelength emitted by the laser chip, and both the pump light absorption layers and the laser emission layers are made of intrinsic semiconductor or compound semiconductor materials.

[0015] Optionally, the carrier diffusion barrier layer includes:

[0016] The potential barrier of the excitation light absorption layer is higher than that of the laser emission layer, and the potential barriers of the carrier diffusion barrier layers are all higher than those of the excitation light absorption layer and the laser emission layer.

[0017] Optionally, the laser coupling output mirror includes:

[0018] It is coated with a dielectric film layer having a transmittance to the laser wavelength emitted by the laser chip.

[0019] Compared with the prior art, the present invention:

[0020] First, in the present invention, a polarization-type heat dissipation window plate is bonded outside the physical and chemical protection layer of the laser chip. By setting the angle between the bonding edge and the Brewster edge, it is ensured that when the laser in the resonant cavity is incident on the Brewster edge, the incident angle is equal to the Brewster angle, so that all s polarization states in the laser beam are reflected and escape from the resonant cavity, leaving only the p polarization state of the laser forming resonance. Therefore, it is ensured that the output laser is linearly polarized p-polarized light. Second, the polarization-type heat dissipation window plate can also play a role in dissipating heat from the laser chip. Because the polarization-type heat dissipation window plate uses a material with high thermal conductivity and is very close to the laser gain region in the chip, it can effectively dissipate heat from the laser chip. Finally, in the present invention, without the need to additionally insert other special polarization elements in the resonant cavity, a linearly polarized laser output can be obtained. Therefore, other elements for selecting the polarization of the laser can be omitted, thereby reducing the intracavity loss of the laser, reducing the threshold of the laser, improving the efficiency and output power of the laser, and since the number of elements inserted in the laser cavity is reduced, the laser can be made more compact, more convenient to adjust, and the stability and reliability of the laser are further improved. Description of the Drawings

[0021] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic structural diagram of the laser chip in the present invention;

[0024] Figure 2 It is a schematic structural diagram of a frequency-doubling laser formed by using the laser chip of the present invention.

[0025] Description of the Reference Numerals

[0026] 1. Chip epitaxial growth substrate; 2. Distributed multi-layer film high reflector; 3. Laser gain region; 4. Carrier diffusion barrier layer; 5. Physical and chemical protection layer; 6. Polarization type heat dissipation window piece; 7. Brewster edge; 8. Normal; 9. Brewster angle; 10. Laser coupling output mirror; 11. Reflected light; 12. s polarization state; 13. p polarization laser beam; 14. p polarization state; 15. Fully polarized laser beam; 16. s polarization state and p polarization state; 17. High refractive index material layer; 18. Low refractive index material layer; 19. Pump light absorption layer; 20. Laser emission layer; 21. Bonding interface; 22. Laser chip; 23. Temperature control and heat dissipation device; 24. Pump beam; 25. Second coupling output mirror; 26. Rear mirror; 27. Nonlinear crystal; 28. Fundamental wave laser beam; 29. Frequency-converted laser beam. Detailed implementation manners

[0027] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other implementation cases obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application. In the embodiments of the present invention, functional units with the same reference numerals have the same and similar structures and functions.

[0028] See Figure 1 and Figure 2 , a laser chip 22 with polarization selection characteristics, comprising:

[0029] A chip epitaxial growth substrate 1, a distributed multi-layer film high reflector 2, a laser gain region 3, a carrier diffusion barrier layer 4, a physical and chemical protection layer 5, and a polarization type heat dissipation window piece 6 connected in sequence, and a laser coupling output mirror 10 provided at one end of the polarization type heat dissipation window piece 6 away from the physical and chemical protection layer 5;

[0030] The cross-section of the polarization type heat dissipation window piece 6 is a right triangle, and any right-angled side of the polarization type heat dissipation window piece 6 is bonded to the physical and chemical protection layer 5 through a bonding interface 21, and the included angle between any bonded right-angled side and the Brewster edge 7 of its opposite side is 68°.

[0031] In this embodiment, the laser gain region 3 can absorb the energy of an external excitation light source, generate photoexcited carriers and undergo radiative transitions. The laser coupling output mirror 10 and the distributed multi-layer film high reflector 2 in the chip form a laser resonator. The radiative transition in the laser gain region 3 is converted into stimulated emission optical amplification in the resonator, forming a laser output. The polarization-type heat dissipation window chip 6 bonded to the chip can not only dissipate heat from the chip, but also convert the laser resonating in the cavity into linearly polarized light, and output a p-polarized laser beam 13 through the laser coupling output mirror 10; the polarization-type heat dissipation window chip 6 is made of a material with high thermal conductivity and is transparent to the wavelength of the external excitation light beam 24 and the laser wavelength, and has the dual functions of dissipating heat from the laser chip 22 and converting the laser in the laser resonator into linearly polarized light. Between the polarization-type heat dissipation window chip 6 and the physical and chemical protection layer 5, they are tightly bonded together through a bonding interface 21 that is transparent to the wavelength of the external excitation light beam 24 and the laser wavelength. This interface can withstand the high temperature generated by the laser. One right-angle side of the polarization-type heat dissipation window chip 6 is bonded to the physical and chemical protection layer 5 of the laser chip 22 through the bonding interface 21. This interface combines the two interfaces through molecular force or atomic force, can withstand the high temperature during laser emission, and is transparent to the laser wavelength and the wavelength of the external excitation light beam 24.

[0032] Among them, the opposite side of the above-mentioned bonded right-angle side is the Brewster side 7, and the corresponding normal line 8 is the normal line 8 of the Brewster side 7. Moreover, the angle between the Brewster side 7 and the bonded right-angle side must ensure that when the laser is incident on the Brewster side 7, its incident angle is equal to the Brewster angle 9 corresponding to the laser wavelength and the material of the polarization-type heat dissipation window chip 6. In this case, when the laser oscillates in the laser resonator formed by the distributed multi-layer film high reflector 2 and the laser coupling output mirror 10 together, the reflected light of the laser on the Brewster side 7, that is, the reflected light ray 11 on the Brewster side 7, is in the s polarization state 12. Also, because the laser will experience countless round trips in the resonator, and every time it passes through the Brewster side 7, the s polarization state 12 in the fully polarized laser beam 15 with s polarization state and p polarization state 16 generated inside the laser chip 22 will be reflected off. Therefore, only the p polarization state 14 remains, so the output through the laser coupling output mirror 10 is a linearly polarized p-polarized laser beam 13.

[0033] See Figure 1 , in another embodiment, the chip epitaxial growth substrate 1 includes:

[0034] It uses an intrinsic semiconductor or compound semiconductor material, and the lattice constant of the chip epitaxial growth substrate 1 matches the lattice constants of the materials used for the distributed multi-layer film high reflector 2, the laser gain region 3, the carrier diffusion barrier layer 4, the physical and chemical protection layer 5, the polarization-type heat dissipation window chip 6, and the laser coupling output mirror 10.

[0035] The lattice constant of the chip epitaxial growth substrate 1 matches the lattice constants of the materials used in the distributed multi-layer film high reflector 2, the laser gain region 3, the carrier diffusion barrier layer 4, the physical and chemical protection layer 5, the polarization type heat dissipation window piece 6, and the laser coupling output mirror 10. If the above matching is detuned, other material layers for compensating the detuning can be added to the chip.

[0036] See Figure 1 and Figure 2 , in another embodiment, the distributed multi-layer film high reflector 2 includes:

[0037] It is composed of alternating high refractive index material layers 17 and low refractive index material layers 18. The optical thickness of each high refractive index material layer 17 and low refractive index material layer 18 is equal to one quarter of the laser wavelength emitted by the laser chip 22, and both the high refractive index material layers 17 and low refractive index material layers 18 are made of intrinsic semiconductor or compound semiconductor materials.

[0038] The materials used for each high refractive index material layer 17 and low refractive index material layer 18 are all intrinsic semiconductor or compound semiconductor materials, and the lattice constants of the materials are approximately matched with the lattice constant of the material of the chip epitaxial growth substrate 1(1).

[0039] See Figure 1 , in another embodiment, the laser gain region 3 includes:

[0040] It is composed of alternating pump light absorption layers 19 and laser emission layers 20. The sum of the thicknesses of each pump light absorption layer 19 and laser emission layer 20 is equal to one half of the laser wavelength emitted by the laser chip 22, and both the pump light absorption layers 19 and laser emission layers 20 are made of intrinsic semiconductor or compound semiconductor materials, and the lattice constants are approximately matched with the lattice constant of the material of the chip epitaxial growth substrate 1(1).

[0041] See Figure 1 , in another embodiment, the carrier diffusion barrier layer 4 includes:

[0042] The potential barrier of the pump light absorption layer 19 is higher than the potential barrier of the laser emission layer 20, and the potential barriers of the carrier diffusion barrier layer 4 are all higher than the potential barriers of the pump light absorption layer 19 and the laser emission layer 20.

[0043] Among them, the barrier of the pump light absorption layer 19 is relatively high, and the barrier of the laser emission layer 20 is relatively low. The pump light absorption layer 19 can absorb the light energy emitted by the external pump beam 24 to generate photo-generated carriers; these photo-generated carriers diffuse into the laser emission layer 20 with a lower barrier and undergo radiative transitions. The thickness of the laser emission layer 20 is on the order of several nanometers, with quantum effects, and each laser emission layer 20 in the chip is located at the peak of the laser standing wave field in the chip, forming a resonant periodic gain structure to provide maximum gain for the laser.

[0044] Moreover, the material barrier of the carrier diffusion blocking layer 4 is higher than the material barriers of the pump light absorption layer 19 and the laser emission layer 20 in the laser gain region 3, and can block the diffusion of the photo-generated carriers generated in the pump light absorption layer 19 to the surface of the chip to generate non-radiative recombination. The carrier diffusion blocking layer 4 is transparent to the light emitted by the external pump beam 24 and is also transparent to the laser wavelength.

[0045] See Figure 1 , in another embodiment, the laser coupling output mirror 10 includes:

[0046] It is coated with a dielectric film layer having a transmittance to the laser wavelength emitted by the laser chip 22

[0047] The laser coupling output mirror 10 is coated with a dielectric film layer having a certain transmittance to the laser wavelength, and together with the distributed multi-layer film high reflector 2 in the laser chip 22, forms a laser resonant cavity.

[0048] See Figure 1 and Figure 2, the working principle of the present invention is as follows: When the external excitation light beam 24 is incident on the laser chip 22, the excitation light will pass through the physical and chemical protection layer 5 and the carrier diffusion barrier layer 4 of the laser chip 22 and reach the laser gain region 3. The bandgap energy of the material of the excitation light absorption layer 19 in the laser gain region 3 is slightly smaller than the photon energy of the externally incident excitation light used, so it can absorb the energy of the photons emitted by the external excitation light source. After the excitation light absorption layer 19 absorbs the energy of the external excitation light, photo-generated carriers are generated therein. Since the material barrier of the excitation light absorption layer 19 is higher than that of the laser emission layer 20, the photo-generated carriers generated in the excitation light absorption layer 19 will diffuse into the laser emission layer 20 through diffusion and be confined therein, emitting radiative transitions. The external laser coupling output mirror 10 and the distributed multi-layer film high-reflection mirror 2 in the laser chip 22 form a laser resonator. The radiative transitions in the laser emission layer 20 resonate in the laser resonator, generating stimulated emission and being amplified, that is, the amplification of light by stimulated emission, to form laser output. The central wavelength of the radiative transitions generated in the laser emission layer 20 is the laser wavelength. The bandgap energy of the material used for the carrier diffusion barrier layer 4 in the laser chip 22 is higher than the bandgap energies of the materials of the excitation light absorption layer 19 and the laser emission layer 20 in the laser gain region 3, so it can prevent the photo-generated carriers generated in the excitation light absorption layer 19 from diffusing to the surface of the laser chip 22 to generate non-radiative recombination. The outermost physical and chemical protection layer 5 of the chip can provide physical and chemical protection for the chip, especially protecting all the epitaxial layers in the chip from being oxidized in the air.

[0049] Outside the physical and chemical protection layer 5 of the laser chip 22, a polarization-type heat dissipation window piece 6 with a right-angled triangular cross-section is bonded, which plays two roles at the same time. One is to dissipate heat from the laser chip 22. The polarization-type heat dissipation window piece 6 uses a material with high thermal conductivity, and it is very close to the laser gain region 3 in the chip, so it can effectively dissipate heat from the laser chip 22. The other is to select the polarization of the laser. One right-angled side of the polarization-type heat dissipation window piece 6 is bonded to the physical and chemical protection layer 5 of the laser chip 22. The opposite side of the bonded right-angled side is the Brewster edge 7, and the angle between it and the bonded right-angled side is such that when the laser is incident on the Brewster edge 7, the incident angle is equal to the Brewster angle 9 corresponding to the laser wavelength and the material of the polarization-type heat dissipation window piece 6. When the laser oscillates in the laser resonator formed by the distributed multi-layer film high-reflection mirror 2 and the laser coupling output mirror 10 together, the reflected light of the laser on the Brewster edge 7 is in the s polarization state 12. Also, because the laser will experience countless round trips in the resonator, and each time it passes through the Brewster edge 7, the s polarization state 12 in the fully polarized laser beam 15 with s polarization state and p polarization state 16 generated inside the laser chip 22 will be reflected off, so only the p polarization state 14 remains. Therefore, the linearly polarized p-polarized laser beam 13 output through the laser coupling output mirror 10.

[0050] And a specific embodiment is provided to illustrate the above technical solution:

[0051] Referring to Figure 2 , the pumping beam 24 is a fiber-coupled output semiconductor laser with an emission wavelength of 808 nm, and the core diameter of the coupled optical fiber is 400 μm. After passing through an achromatic lens pair with 1:1 imaging, the pumping beam 24 is focused and imaged on the surface of the laser chip 22, and the focal length of the focusing is 45 mm.

[0052] The overall size of the laser chip 22 is 4 mm × 4 mm, and the chip epitaxial growth substrate 1 therein is an undoped GaAs substrate with a thickness of 350 μm. The high refractive index material layer 17 in the distributed multi-layer high reflector 2 is an Al0.1GaAs layer with a thickness of 70 nm, and the low refractive index material layer 18 is an Al0.9GaAs layer with a thickness of 81 nm. One high refractive index material layer 17 and one low refractive index material layer 18 form a pair, and the distributed multi-layer high reflector 2 has 27.5 pairs of such material layers. The central wavelength of the high reflection spectrum generated by it is 960 nm, and the reflection bandwidth of the high reflectivity is 80 nm. The pumping light absorption layer 19 in the laser gain region 3 is a GaAsP0.02 layer with a thickness of 150 nm, and the laser emission layer 20 in the laser gain region 3 is an In0.12GaAs layer with a thickness of 8 nm. The 150-nm GaAsP0.02 layer with a high potential barrier can absorb the energy of the 808-nm laser light, and the central wavelength of the emission spectrum of the In0.12GaAs material layer with a low potential barrier is 960 nm. The carrier diffusion barrier layer 4 is an In0.5GaP layer with a thickness of 160 nm. The physical and chemical protection layer 5 is a GaAs layer with a thickness of 20 nm.

[0053] The polarization-type heat dissipation window piece 6 is a diamond block with high thermal conductivity, and its thermal conductivity is above 1800 Wm-1K-1. The cross-section of the polarization-type heat dissipation window piece 6 is a right triangle, and the length of the right-angle side bonded to the physical and chemical protection layer 5 is 8 mm. The included angle between the bonded side and its opposite side, i.e., the Brewster side 7, is 68°. Liquid capillary bonding is adopted between the physical and chemical protection layer 5 and the polarization-type heat dissipation window piece 6, and the bonding interface 21 is the liquid capillary bonding interface 21.

[0054] The temperature control and heat dissipation device 23 is a thermoelectric cooling TEC module with accurate temperature control. The second coupled output mirror 25 is a BK7 plano-concave reflector with a diameter of 12.7 mm, a central thickness of 3 mm, and a radius of curvature of 50 mm. Its S1 surface is coated with a dielectric film layer with a transmittance of 1% for the 960 nm laser wavelength, and its S2 surface is coated with a film layer with a high transmittance for the 960 nm laser wavelength. The rear-end mirror 26 is a plane mirror coated with a dielectric film layer with a high reflectivity for the 960 nm laser wavelength. The nonlinear crystal 27 is a type-I phase-matching LBO crystal, and both of its light-passing end faces are coated with a film layer with a high transmittance for the fundamental wave laser wavelength of 960 nm and the second-harmonic laser wavelength of 480 nm. The operating temperature of the crystal is room temperature.

[0055] Under the above conditions, the fundamental wave laser beam 28 obtained by the laser is a linearly polarized light laser beam with a wavelength of 960 nm and p polarization, and the frequency-converted laser beam 29 is a linearly polarized laser beam with a wavelength of 480 nm and s polarization.

[0056] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0057] The above description is only the specific implementation manners of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A laser chip with polarization selection characteristics, characterized in that, Comprising: A chip epitaxial growth substrate (1), a distributed multi-layer film high reflector (2), a laser gain region (3), a carrier diffusion barrier layer (4), a physical and chemical protection layer (5), and a polarization type heat dissipation window sheet (6) connected in sequence, and a laser coupling output mirror (10) provided at one end of the polarization type heat dissipation window sheet (6) away from the physical and chemical protection layer (5); The cross-section of the polarization type heat dissipation window sheet (6) is a right triangle, and any right side of the polarization type heat dissipation window sheet (6) is bonded to the physical and chemical protection layer (5) through a bonding interface (21), and the included angle between any bonded right side and the Brewster side of its opposite side is 68°.

2. The laser chip with polarization selection characteristics according to claim 1, wherein The chip epitaxial growth substrate (1) includes: It is made of an intrinsic semiconductor or compound semiconductor material, and the lattice constant of the chip epitaxial growth substrate (1) is matched with the lattice constants of the materials used in the distributed multi-layer film high reflector (2), the laser gain region (3), the carrier diffusion barrier layer (4), the physical and chemical protection layer (5), the polarization type heat dissipation window sheet (6), and the laser coupling output mirror (10).

3. The laser chip with polarization selection characteristics according to claim 1, wherein The distributed multi-layer film high reflector (2) includes: It is composed of high refractive index material layers (17) and low refractive index material layers (18) alternatingly, and the optical thickness of each high refractive index material layer (17) and low refractive index material layer (18) is equal to one-fourth of the laser wavelength emitted by the laser chip, and both the high refractive index material layers (17) and low refractive index material layers (18) are made of intrinsic semiconductor or compound semiconductor materials.

4. The laser chip with polarization selection characteristics according to claim 1, characterized in that, The laser gain region (3) includes: It is composed of pump light absorption layers (19) and laser emission layers (20) alternatingly, and the sum of the thicknesses of each pump light absorption layer (19) and laser emission layer (20) is equal to one-half of the laser wavelength emitted by the laser chip, and both the pump light absorption layers (19) and laser emission layers (20) are made of intrinsic semiconductor or compound semiconductor materials.

5. The laser chip with polarization selection characteristics according to claim 4, characterized in that, The carrier diffusion barrier layer (4) includes: The potential barrier of the pump light absorption layer (19) is higher than that of the laser emission layer (20), and the potential barriers of the carrier diffusion barrier layer (4) are all higher than those of the pump light absorption layer (19) and the laser emission layer (20).

6. The laser chip with polarization selection characteristics according to claim 1, characterized in that, The laser coupling output mirror (10) includes: It is coated with a dielectric film layer having a transmittance to the laser wavelength emitted by the laser chip.

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