A tapered semiconductor laser with integrated superlens

Abstract

The application discloses a kind of integrated superlenses' conical semiconductor laser, belong to semiconductor laser technical field, including conical structure, the conical structure includes narrow ridge-shaped waveguide portion, with narrow ridge-shaped waveguide portion connected conical gain amplification portion;It further includes superlens, the superlens is set in conical gain amplification portion far from narrow ridge-shaped waveguide portion one end;The superlens includes several longitudinal low refractive index units and several residual longitudinal waveguides, the longitudinal low refractive index unit and residual longitudinal waveguide are alternately arranged along the width direction of conical gain amplification portion;The present application can greatly reduce horizontal direction divergence angle, improve semiconductor laser beam quality, improve laser output power, realize stable lateral mode output.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of integrated hyperlens's conical semiconductor laser, belong to semiconductor laser technical field. BACKGROUND

[0002] Semiconductor laser has many advantages such as light weight, small size, low cost, easy integration, etc., and is widely used in material processing, communication, military, medical and many other fields. However, in these applications, including as the pump source of solid-state and fiber laser, laser scalpel, laser weapon, metal cutting and welding, laser display, etc., there are high requirements for the brightness of the laser. High brightness requires high output power and high beam quality. Traditional wide-contact semiconductor lasers can achieve high single-tube output power and power conversion efficiency, but due to the wide output aperture, it is easy to cause lateral multimode, resulting in poor beam quality. On the other hand, ridge waveguide lasers can achieve lateral near-diffraction-limited output, but are limited by small output aperture and gain volume, and have low power.

[0003] In some laser structure designs with high beam quality and high output power, conical lasers have the advantages of simple structure and low process difficulty. Conical lasers include a ridge waveguide part with mode selection and a conical gain part for mode amplification. Conical lasers with a large conical angle of 4 to 6 degrees have been reported to achieve high-power and high-beam-quality laser output. However, a large gain conical angle on the one hand causes the light in the conical gain amplification part to become nearly free-propagating divergent light, greatly increasing the lateral far-field divergence angle, and the full width at 1 / e 2 energy is usually more than 10°, which needs to be combined with complex beam shaping for application, hindering the expansion of its application field, on the other hand, greatly widens the lateral aperture of the output end face, more easily causes lateral multimode lasing, and further causes the decline of beam quality.

[0004] Therefore, it is necessary to propose a conical semiconductor laser integrated with a hyperlens, which has good comprehensive performance: can greatly reduce the horizontal divergence angle, improve the beam quality of the semiconductor laser, increase the laser output power, and realize stable lateral mode output.

[0005] As can be seen from the above, the prior art has obvious inconvenience and defects in actual use, and therefore needs to be improved. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a conical semiconductor laser integrated with a hyperlens, which can greatly reduce the horizontal divergence angle, improve the beam quality of the semiconductor laser, increase the laser output power, and realize stable lateral mode output.

[0007] To solve the above technical problems, the application adopts the following technical scheme: a cone-shaped semiconductor laser integrated with a superlens, comprising a cone-shaped structure, the cone-shaped structure comprising a narrow ridge-shaped waveguide part and a cone-shaped gain amplification part connected with the narrow ridge-shaped waveguide part; further comprising a superlens, the superlens being arranged at one end of the cone-shaped gain amplification part away from the narrow ridge-shaped waveguide part.

[0008] The superlens comprises a plurality of longitudinal low-refractive-index units and a plurality of residual longitudinal waveguides, the longitudinal low-refractive-index units and the residual longitudinal waveguides being arranged alternately along the width direction of the cone-shaped gain amplification part.

[0009] Further, all the longitudinal low-refractive-index units in the superlens have the same refractive index, and the refractive index difference between the longitudinal low-refractive-index units and the residual longitudinal waveguides is greater than 0.5.

[0010] Further, the epitaxial structure comprises, from bottom to top, an N-type substrate, an N-type confinement layer, an N-type waveguide layer, an active region, a P-type waveguide layer, a P-type confinement layer and a P-type contact layer; the superlens spans the active region in the epitaxial direction.

[0011] Further, the longitudinal low-refractive-index unit is formed by one longitudinal refractive index subzone;

[0012] Alternatively, the longitudinal low-refractive-index unit is composed of a plurality of longitudinal refractive index subzones arranged in a row and spaced apart; and the number of longitudinal refractive index subzones in the longitudinal low-refractive-index units at different positions of the cone-shaped gain amplification part is the same or different.

[0013] Further, the quasi-periodic width of the superlens is of a subwavelength order.

[0014] Further, the longitudinal low-refractive-index unit comprises a longitudinal low-refractive-index groove; the longitudinal low-refractive-index groove is formed by etching downward along the upper surface of the cone-shaped gain amplification part;

[0015] The longitudinal low-refractive-index groove forms the longitudinal low-refractive-index unit by itself, or a material with a lower refractive index than the residual longitudinal waveguide is filled into the longitudinal low-refractive-index groove to form the longitudinal low-refractive-index unit.

[0016] Further, the depth of the longitudinal low-refractive-index groove exceeds the depth of the active region; the length and width of the longitudinal low-refractive-index groove at different lateral positions of the cone-shaped gain amplification part are different.

[0017] Further, the taper structure is arranged on one side of the epitaxial layer structure provided with a P-type contact layer; the end face of the taper gain amplification part away from the narrow ridge waveguide part is the front cavity face of the laser; the end face of the narrow ridge waveguide part away from the taper gain amplification part is the rear cavity face of the taper semiconductor laser; and the width of the taper gain amplification part gradually increases along the light emission direction.

[0018] Further, the width of the narrow ridge waveguide part is not greater than the cutoff width of the lateral high-order mode generated at the abrupt change of the taper gain amplification part.

[0019] The narrow ridge waveguide part forms a refractive index guiding structure.

[0020] The contact layers on both sides of the taper gain amplification part are etched to form gain guiding, or the taper gain amplification part and the narrow ridge waveguide part are etched to the same depth to form a refractive index guiding structure.

[0021] Further, the front cavity face is externally coated with an anti-reflection film with a reflectivity less than 1%.

[0022] The rear cavity face is externally coated with a high-reflection film and etched to form a damage groove on both sides of the narrow ridge waveguide part, or a DBR grating is etched in the rear cavity face.

[0023] Compared with the prior art, the present application has the following advantages after adopting the above technical scheme:

[0024] (1) The superlens of the present application finely adjusts the width and length of the longitudinal low-refractive-index unit according to the lateral position. Different length-width distributions make the changed phase of the light after transmission change with the change of the lateral position, thereby converting the divergent light of the taper gain amplification part into parallel light or convergent light, greatly reducing the lateral far-field divergence angle. In the ideal case of only the fundamental lateral mode lasing, the taper waveguide with a length of millimeter level can theoretically obtain a horizontal divergence angle less than 0.9°, which is one order of magnitude lower than that of the conventional taper laser.

[0025] (2) The different length-width distributions of the longitudinal low-refractive-index unit make the reflectivity and light loss of the light change with the change of the lateral position. There is relatively high reflectivity and relatively low loss at the position where the lateral fundamental mode light field mainly distributes, and there is relatively low reflectivity and relatively high loss at the position where the lateral high-order mode light field mainly distributes, so that the high-order modes of the taper cavity are suppressed, thereby obtaining high-beam-quality laser output.

[0026] (3) When light is diffracted in the conical gain amplification part, there are high-order diffraction peaks. Their phases are discontinuous with the phase of the 0th-order diffraction peak, and there is a sudden change in phase. In the far field, there is a phenomenon of interference destructiveness, which reduces the optical power in the far field. In order to overcome the above problems, it is now common to reduce the cone angle of the conical gain amplification part to suppress the high-order diffraction peaks. However, this greatly reduces the gain area of ​​the conical gain amplification part and limits the improvement of optical power. In the present invention, by designing a metalens at the position of the high-order diffraction peak and adjusting the phase of its transmitted light, it is possible to convert the interference destructive light into interference constructive light, thereby allowing the device to have a larger cone angle and gain area, and greatly improving the output power of the device.

[0027] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the integrated superlens conical semiconductor laser of the present invention;

[0029] Figure 2 1 is a schematic diagram of the enlarged structure of the metalens of the present invention;

[0030] Figure 3 for Figure 1 Schematic diagram of electric field mode distribution of a simulation model of a tapered region of a tapered semiconductor laser with an integrated superlens;

[0031] Figure 4 for Figure 2 Schematic diagram of the TE mode electric field distribution at a certain moment in a simulation model of the area near the metalens shown;

[0032] Figure 5 For simulation Figure 2 Schematic diagram of the relationship between the light transmittance of the metalens shown and the length and width of the longitudinal low refractive index unit;

[0033] Figure 6 For simulation Figure 2 Schematic diagram of the relationship between the light reflectivity of the metalens shown and the length and width of the longitudinal low refractive index unit;

[0034] Figure 7 For simulation Figure 2 Schematic diagram of the relationship between the optical loss rate of the metalens shown and the length and width of the longitudinal low-refractive-index unit;

[0035] Figure 8 for Figure 1 Schematic diagram of electric field mode distribution of another simulation model of the tapered region of the tapered semiconductor laser with integrated superlens;

[0036] Figure 9 For simulation Figure 8Schematic diagram of the horizontal output far field of the tapered semiconductor laser with integrated superlens shown;

[0037] Figure 10 Schematic diagram of the propagation of light waves after passing through the tapered gain amplification part;

[0038] Figure 11 Schematic top view of the tapered gain amplification portion of the integrated metalens;

[0039] Figure 12 Schematic diagram of the phase modulation of the metalens under different lengths and widths of the low-refractive-index unit.

[0040] In the figure,

[0041] 11-back cavity surface, 12-narrow ridge waveguide portion, 13-tapered gain amplifier portion, 14-front cavity surface, 15-super lens, 16-longitudinal low refractive index groove, 17-remaining longitudinal waveguide. DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0043] Example 1

[0044] like Figure 1 and Figure 2 As shown together, the present invention provides a conical semiconductor laser with an integrated superlens, comprising: an epitaxial layer structure, a conical structure and a superlens 15, wherein the epitaxial structure comprises an N-type substrate, an N-type confinement layer, an N-type waveguide layer, an active region, a P-type waveguide layer, a P-type confinement layer and a P-type contact layer arranged in sequence from bottom to top.

[0045] The tapered structure is arranged on a side of the epitaxial layer structure provided with a P-type contact layer, and the tapered structure includes a narrow ridge waveguide portion 12 and a tapered gain amplifier portion 13 connected to the narrow ridge waveguide portion 12. The end face of the narrow ridge waveguide portion 12 away from the tapered gain amplifier portion 13 is a back cavity facet 11 of the tapered semiconductor laser, and the end face of the tapered gain amplifier portion 13 away from the narrow ridge waveguide portion 12 is a front cavity facet 14 of the tapered semiconductor laser; the width of the tapered gain amplifier portion 13 gradually increases along the light output direction.

[0046] The metalens 15 is disposed at the end of the tapered gain amplification section 13 away from the narrow ridge waveguide section 12. The metalens 15 spans the active region in the epitaxial direction. The metalens 15 comprises a plurality of longitudinal low-refractive-index units and a plurality of residual longitudinal waveguides 17. The longitudinal low-refractive-index units and residual longitudinal waveguides 17 are alternately arranged along the width of the tapered gain amplification section 13.

[0047] All longitudinal low refractive index units in the superlens 15 have the same refractive index, and the refractive index difference between the longitudinal low refractive index units and the rest longitudinal waveguide 17 is greater than 0.5.

[0048] The longitudinal low refractive index units are continuous structures, i.e. the longitudinal low refractive index units are formed by one longitudinal refractive index section; or the longitudinal low refractive index units are discontinuous structures, i.e. the longitudinal low refractive index units are composed of multiple longitudinal refractive index sections arranged in rows and spaced apart; and the number of longitudinal refractive index sections in the longitudinal low refractive index units at different positions of the tapered gain amplification part 13 is the same or different, which can reduce transmission loss and select modes.

[0049] Further, the longitudinal low refractive index units include longitudinal low refractive index grooves 16; the longitudinal low refractive index grooves 16 are formed by etching downward along the upper surface of the tapered gain amplification part 13; the longitudinal low refractive index grooves 16 form the longitudinal low refractive index units alone, or the longitudinal low refractive index units are formed by filling materials with lower refractive index than the rest longitudinal waveguide 17 into the longitudinal low refractive index grooves 16.

[0050] It should be noted that when the longitudinal low refractive index units are composed of multiple longitudinal refractive index sections, the longitudinal low refractive index grooves 16 are correspondingly arranged in multiple, and the multiple longitudinal low refractive index grooves 16 are arranged in rows and spaced apart.

[0051] The quasi-periodic width of the superlens 15 is of subwavelength magnitude, so as to bypass the formation of stray diffraction orders and avoid the adverse effects of virtual focal spots, halos, etc. caused by the stray diffraction orders.

[0052] The depth of the longitudinal low refractive index grooves 16 exceeds the depth of the active region; the length and width of the longitudinal low refractive index grooves 16 at different lateral positions of the tapered gain amplification part 13 are different.

[0053] It should be noted that the position of the tapered gain amplification part 13 in the width direction is the lateral position.

[0054] The width of the narrow ridge waveguide part 12 is not greater than the cutoff width of the lateral high-order modes generated at the abrupt change of the tapered gain amplification part 13.

[0055] Preferably, the narrow ridge waveguide part 12 forms a refractive index guide structure.

[0056] Preferably, the contact layer on both sides of the tapered gain amplification part 13 is etched to form a gain guide, or the tapered gain amplification part 13 and the narrow ridge waveguide part 12 are etched to the same depth to form a refractive index guide structure.

[0057] The length of the tapered gain amplification section 13 and the ridge narrow ridge waveguide section 12 is selected according to the device design requirements, to ensure that sufficient lateral mode filtering characteristics and sufficient gain volume are obtained.

[0058] The front cavity surface 14 is coated with an anti-reflection film, and the reflectivity is less than 1%;

[0059] Preferably, the rear cavity surface 11 is coated with a high-reflection film and etched with a damage groove on both sides of the narrow ridge waveguide section 12, or a DBR grating is etched in the rear cavity surface 11.

[0060] Specifically, the length and width of the longitudinal low-refractive-index groove 16 are adjusted according to the change of the lateral position of the tapered gain amplification section 13: the length and width distribution makes the phase distribution of the outgoing light meet the convergence condition or the parallel outgoing condition, and makes the main distribution position of the lateral fundamental mode light field have relatively high reflectivity and transmissivity, and makes the main distribution position of the lateral high-order mode light field have relatively low reflectivity and relatively high loss.

[0061] Wherein, Figure 10 is a schematic diagram of the propagation of light waves after passing through the tapered gain amplification section, without considering the effects of temperature and carriers, the refractive index of the tapered gain amplification section 13 is constant, and cannot compensate for the phase difference caused by the optical path. The outgoing light of the narrow ridge waveguide section is approximated as a point light source, and the wavefront of the outgoing wave is a diverging spherical wave, which obviously causes an increase in the far-field divergence angle.

[0062] In order to change the transmission phase of electromagnetic waves, an superlens 15 is integrated in the region close to the exit end surface, and one or more longitudinal low-refractive-index units are placed at different lateral (y direction, i.e. width direction of the tapered gain amplification section) positions, each small unit corresponds to a resonant cavity, and by changing the size of the small unit, different transmission phases are realized, such as Figure 11 As shown in the figure, it is a top view of the tapered gain amplification section integrated with the superlens, the left is the narrow ridge waveguide section, the middle is the tapered gain amplification section and the superlens, and the middle rectangle is the longitudinal low-refractive-index unit. The coordinates of each small unit are taken as y i , the phase zero point is taken at the center of the entrance of the tapered gain amplification section , the y coordinate of this position is taken as , and the distance from the entrance of the tapered gain amplification section to the superlens is L.

[0063] The phase change of the light wave entering from the entrance of the tapered gain amplification section after passing through the superlens is composed of 2 parts, the first part is the phase change generated by the transmission of light from the entrance of the tapered gain amplification section to the superlens, which can be represented as:

[0064] , wherein is the wave number in free space, λ dis the wavelength, n is the equivalent refractive index of the tapered gain amplifier in the top view plane, d i is the distance from the center of the longitudinal low refractive index unit at different positions to the entrance of the tapered gain amplifier part.

[0065] To make the outgoing light convergent or parallel, the phase of the final outgoing light must meet the following conditions:

[0066] , where f is the focal length (the focal length of parallel light is ∞) and n0 is the refractive index of the external medium.

[0067] Then, the phase change in part 2 can be calculated , that is, the required phase change caused by the metalens is:

[0068] .

[0069] The phase change caused by the metalens at a certain position depends on the size of the low refractive index unit at that position, such as Figure 12 As shown in the figure, the color depth reflects the phase change caused by the metalens when the low refractive index unit is at its corresponding length and width. Next, in Figure 12 Find the points where the phase change is equal to the value calculated by the above formula. The horizontal and vertical coordinates corresponding to these points are the sizes of the low-refractive-index units that can satisfy the above-mentioned phase modulation.

[0070] Furthermore, the lateral fundamental mode light field is mainly distributed in the middle position of the tapered amplification gain part, while the lateral high-order mode (taking the 1st order mode as an example) is mainly distributed on both sides (near the quarter point). Therefore, it is necessary to make the metalens have relatively high reflectivity and transmittance in the middle position of the lateral direction, and relatively low reflectivity and relatively large loss on both sides. Therefore, when designing the low-refractive index unit size at the main distribution position of the lateral base film, it is necessary to select the low-refractive index unit size that meets the phase modulation requirement according to the following formula: Figure 5 、 Figure 6 Select the size with relatively high transmittance and reflectivity; when designing the low refractive index unit size where the lateral high-order mode is mainly distributed, it is necessary to select the size of the low refractive index unit that satisfies the phase modulation according to the following formula: Figure 6 、 Figure 7 Choose a size where reflectivity is relatively low and loss is relatively high.

[0071] It should be noted that: Figure 5 For simulation Figure 2The light transmittance of the superlens varies with the length and width of the longitudinal low refractive index groove. When the width of the low refractive index unit is small, the high transmittance region and the low transmittance region are alternately arranged along the length growth direction. With the increase of the width of the low refractive index unit, the arrangement is bent upwards, and the transmittance of the low transmittance region decreases obviously.

[0072] Figure 6 To simulate Figure 2 The light reflectivity of the superlens varies with the length and width of the longitudinal low refractive index groove. When the width of the low refractive index unit is small, the high reflectivity region and the low reflectivity region are alternately arranged along the length growth direction. With the increase of the width of the low refractive index unit, the arrangement is bent upwards, and the reflectivity of the high reflectivity region increases obviously, which is generally opposite to the change of the transmittance.

[0073] Figure 7 To simulate Figure 2 The light loss rate of the superlens varies with the length and width of the longitudinal low refractive index groove. When the length and width of the low refractive index unit are small, the light loss rate is small. With the increase of the length and width of the low refractive index unit, the high loss and the low loss are alternately arranged along the direction perpendicular to the common increase of the length and width.

[0074] Figure 3 The simulation model of the light field distribution of the tapered gain amplification part of the wavelength 980 nm laser is shown. The tapered gain amplification part 13 adopts a gain guiding structure. The waveguides on both sides have losses, and the gain of the central waveguide is greater than the loss. The width of the left ridge narrow ridge waveguide part 12 is 1.5 μm, which satisfies the lateral high-order mode cutoff condition of the ridge waveguide, and ensures that only the fundamental lateral mode is incident on the tapered gain amplification part 13. The total length of the tapered gain amplification part 13 is 50 μm, and the full taper angle is 10°, which provides a large enough light gain area. The total width of the right superlens 15 is 22 μm, which is greater than the output aperture width. The quasi-periodic width is 275 nm, which ensures that the phase of the TE mode light of the adjacent longitudinal low refractive index groove 16 and the remaining longitudinal waveguide 17 is not dithered. The longitudinal low refractive index groove 16 is made by etching inward from the surface, and the length is 0.5 μm -2.7 μm. The width of the longitudinal low refractive index groove 16 is 66 nm, which can specifically regulate the light at different positions, so that the outgoing light changes from divergent light to parallel light or convergent light (see Figure 4 The light field distribution of the tapered gain amplification part of the wavelength 980 nm laser is shown. The simulation model of the light field distribution of the tapered gain amplification part of the wavelength 980 nm laser is shown. The tapered gain amplification part 13 adopts a gain guiding structure. The waveguides on both sides have losses, and the gain of the central waveguide is greater than the loss. The width of the left ridge narrow ridge waveguide part 12 is 1.5 μm, which satisfies the lateral high-order mode cutoff condition of the ridge waveguide, and ensures that only the fundamental lateral mode is incident on the tapered gain amplification part 13. The total length of the tapered gain amplification part 13 is 50 μm, and the full taper angle is 10°, which provides a large enough light gain area. The total width of the right superlens 15 is 22 μm, which is greater than the output aperture width. The quasi-periodic width is 275 nm, which ensures that the phase of the TE mode light of the adjacent longitudinal low refractive index groove 16 and the remaining longitudinal waveguide 17 is not dithered. The longitudinal low refractive index groove 16 is made by etching inward from the surface, and the length is 0.5 μm -2.7 μm. The width of the longitudinal low refractive index groove 16 is 66 nm, which can specifically regulate the light at different positions, so that the outgoing light changes from divergent light to parallel light or convergent light (see Figure 5 、 Figure 6 and Figure 7As shown in Figure 2), the high-order modes of the tapered cavity are suppressed, the beam quality of the semiconductor laser is improved, the laser output power is increased, and stable lateral mode output is achieved.

[0075] Figure 8 Another simulation model of the optical field distribution of the tapered gain amplification portion of the 980 nm wavelength laser of this embodiment is shown. The tapered gain amplification portion of this simulation model adopts a gain-guiding structure. The narrow ridge waveguide on the left has a width of 4 μm. The tapered gain amplification portion 13 has a length of 0.5 mm and a full cone angle of 6°. The total width of the metalens 15 on the right is approximately 100 μm, which is larger than the output aperture width. The quasi-periodic width is 275 nm, ensuring that the TE mode light phase of the adjacent longitudinal low-refractive-index groove 16 and the remaining longitudinal waveguide 17 is not jittered. The longitudinal low-refractive-index groove 16 is made by surface inward etching, has a length of 0.1 μm to 1.535 μm, and a width of 66 nm. The far-field divergence angle of the lateral fundamental mode obtained by simulation is less than 0.9° (see Figure 9 As shown in the figure, the laser's horizontal divergence angle is reduced by one order of magnitude compared to traditional devices. It also ensures that the main distribution position of the lateral fundamental mode light field has a relatively high reflectivity and relatively low loss, and the main distribution position of the lateral high-order mode light field has a relatively low reflectivity and relatively high loss (see Figure 5 、 Figure 6 and Figure 7 As shown in Figure 2), the high-order modes of the tapered cavity are suppressed, the beam quality of the semiconductor laser is improved, the laser output power is increased, and stable lateral mode output is achieved.

[0076] It should be further explained that the lateral far-field divergence angle is almost inversely proportional to the light output aperture, and the length of the tapered gain amplification section is one of the determining factors of the light output aperture (i.e., the longer the tapered gain amplification section, the larger the light output aperture and the smaller the far-field divergence angle). In this simulation example, the length of the tapered gain amplification section is relatively short, only 500 μm, and the lateral divergence angle has been reduced to 0.81°. Therefore, for real devices generally in the millimeter range, the lateral far-field divergence angle can be less than 0.5°.

[0077] It should be noted that the far-field divergence angle in the above simulation model is obtained by the following methods: 1. The electric field distribution at the light-emitting end face ( Figure 8 Data at the light-emitting end face), after Fourier transformation (such as Figure 9 ), we can find the normalized distribution of light in the far field, and then get the far field divergence angle (half-height width, i.e. Figure 9 The above method for obtaining the far-field divergence angle is a well-known technology and will not be described in detail here.

[0078] The above describes the best mode of the present application, wherein the parts not described in detail are the common knowledge of the ordinary skilled in the art. The scope of protection of the present application is defined by the content of the claims, and any equivalent transformation based on the technical inspiration of the present application is also within the scope of protection of the present application.

Claims

1. A conical semiconductor laser with an integrated superlens, comprising a conical structure, wherein the conical structure comprises a narrow ridge waveguide portion (12) and a conical gain amplifier portion (13) connected to the narrow ridge waveguide portion (12); characterized in that: It also includes a super lens (15), wherein the super lens (15) is arranged at one end of the tapered gain amplifier part (13) away from the narrow ridge waveguide part (12); The metalens (15) comprises a plurality of longitudinal low-refractive-index units and a plurality of remaining longitudinal waveguides (17), wherein the longitudinal low-refractive-index units and the remaining longitudinal waveguides (17) are alternately arranged along the width direction of the tapered gain amplification part (13); The longitudinal low-refractive-index unit comprises a longitudinal low-refractive-index groove (16); the longitudinal low-refractive-index groove (16) is formed by etching downward along the upper surface of the tapered gain amplifying portion (13); and the length and width of the longitudinal low-refractive-index groove (16) at different lateral positions in the width direction of the tapered gain amplifying portion (13) are different.

2. The tapered semiconductor laser with integrated superlens according to claim 1, wherein: All longitudinal low-refractive-index units in the superlens (15) have the same refractive index, and the refractive index difference between the longitudinal low-refractive-index unit and the remaining longitudinal waveguides (17) is greater than 0.

5.

3. The tapered semiconductor laser with integrated superlens according to claim 1, wherein: The invention also includes an epitaxial layer structure, wherein the epitaxial layer structure includes an N-type substrate, an N-type confinement layer, an N-type waveguide layer, an active region, a P-type waveguide layer, a P-type confinement layer and a P-type contact layer arranged in sequence from bottom to top; the super lens (15) spans the active region in the epitaxial direction.

4. The tapered semiconductor laser with integrated superlens according to claim 1, wherein: The longitudinal low refractive index unit is formed by a longitudinal refractive index partition; Alternatively, the longitudinal low refractive index unit is composed of a plurality of longitudinal refractive index partitions arranged in rows and at intervals; and the number of longitudinal refractive index partitions in the longitudinal low refractive index unit at different positions of the tapered gain amplifier part (13) is the same or different.

5. The tapered semiconductor laser with integrated superlens according to claim 1, wherein: The quasi-periodic width of the superlens (15) is on the sub-wavelength order.

6. The tapered semiconductor laser with integrated superlens according to claim 3, wherein: The longitudinal low-refractive-index groove (16) alone forms a longitudinal low-refractive-index unit, or the longitudinal low-refractive-index groove (16) is filled with a material having a lower refractive index than that of the remaining longitudinal waveguide (17) to form a longitudinal low-refractive-index unit.

7. The tapered semiconductor laser with integrated superlens according to claim 6, wherein: The depth of the longitudinal low refractive index groove (16) exceeds the depth of the active area.

8. The tapered semiconductor laser with integrated superlens according to claim 3, wherein: The tapered structure is arranged on a side of the epitaxial layer structure provided with a P-type contact layer; the end face of the tapered gain amplification part (13) away from the narrow ridge waveguide part (12) is the front cavity face (14) of the laser; the end face of the narrow ridge waveguide part (12) away from the tapered gain amplification part (13) is the back cavity face (11) of the tapered semiconductor laser; and the width of the tapered gain amplification part (13) gradually increases along the light output direction.

9. The tapered semiconductor laser with integrated superlens according to claim 1, wherein: The width of the narrow ridge waveguide portion (12) is not greater than the cutoff width of the lateral high-order mode generated at the mutation point of the tapered gain amplifier portion (13); The narrow ridge waveguide portion (12) forms a refractive index guiding structure; The contact layers on both sides of the tapered gain amplification part (13) are etched away to form a gain guide, or the tapered gain amplification part (13) and the narrow ridge waveguide part (12) are etched to the same depth to form a refractive index guiding structure.

10. The tapered semiconductor laser with integrated superlens according to claim 8, characterized in that: The front cavity surface (14) is coated with an antireflection film with a reflectivity of less than 1%; The rear cavity surface (11) is coated with a high-reflection film and destruction grooves are etched on both sides of the narrow ridge waveguide portion (12), or a DBR grating is etched inside the rear cavity surface (11).

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