Integrated composite cylindrical lens for edge-emitting semiconductor laser array

Abstract

The invention provides an integrated composite cylindrical lens for an edge-emitting semiconductor laser array, and the composite cylindrical lens comprises a lens which is formed by processing a single piece of optical glass; wherein the first surface of the lens is a spherical cylindrical mirror surface, the cylindrical axis of the spherical cylindrical mirror surface is parallel to the fast axis direction, and the spherical cylindrical mirror surface is used for expanding and shaping divergent beams in the slow axis direction; the second surface of the lens is an aspheric cylindrical mirror surface, the cylindrical axis of the aspheric cylindrical mirror surface is parallel to the slow axis direction, and the aspheric cylindrical mirror surface is used for compressing and collimating the large-divergence-angle light beam in the fast axis direction; the first surface and the second surface are oppositely arranged and form a composite cylindrical surface optical structure with differentiated curvatures in the fast and slow axis directions, and synchronous shaping of double-axis light beams is achieved. The composite cylindrical lens is formed by processing a single piece of optical glass, and can be integrally installed in front of a linear array laser, so that fast / slow axis synchronous shaping and compact integration are realized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor laser optical shaping, and can be applied to laser radar, ranging, active infrared auxiliary lighting, dot matrix structured light projection and other laser application systems that require large field of view coverage and compact packaging, and is suitable for wide-angle laser application scenarios that do not require absolute light intensity uniformity, and in particular relates to an integrated composite cylindrical lens for an edge-emitting semiconductor laser array. BACKGROUND

[0002] Edge-emitting semiconductor lasers have significant differences in divergence angles in the fast axis and slow axis directions, and usually require a multi-stage optical system to achieve fast axis collimation and slow axis expansion. The traditional arc arrangement scheme for slow axis expansion requires that the chips be individually mounted on a customized metal base at a certain angle, and a fast axis collimation lens (FAC) is separately attached, which has a complex structure and is difficult to assemble and adjust, and is prone to angle errors, especially in multi-channel systems, collimation consistency and yield control are difficult. In addition, the traditional two-stage optical path scheme with separate FAC and slow axis cylindrical lens has a long structure and low integration, which has been difficult to meet the needs of high-density and high-consistency applications. SUMMARY

[0003] In view of the above problems, the present disclosure provides an integrated composite cylindrical lens for an edge-emitting semiconductor laser array, which can simultaneously achieve fast axis compression and slow axis angle expansion in a single piece, simplifying the optical path design and improving system compactness and assembly efficiency to solve the above technical problems.

[0004] An aspect of an embodiment of the present disclosure provides an integrated composite cylindrical lens for an edge-emitting semiconductor laser array, comprising: a lens formed by a single piece of optical glass; wherein a first surface of the lens is a spherical cylindrical mirror surface, the cylindrical axis of the spherical cylindrical mirror surface is parallel to the fast axis direction, and the spherical cylindrical mirror surface is used to expand and shape the divergent light in the slow axis direction; a second surface of the lens is an aspherical cylindrical mirror surface, the cylindrical axis of the aspherical cylindrical mirror surface is parallel to the slow axis direction, and the aspherical cylindrical mirror surface is used to compress and collimate the large divergence angle light beam in the fast axis direction; the first surface and the second surface are oppositely arranged, and the two constitute a composite cylindrical optical structure with differential curvature in the fast and slow axis directions, to realize synchronous shaping of the double-axis light beam.

[0005] According to an embodiment of the present disclosure, the surface type parameters of the aspherical cylindrical mirror surface include negative curvature, conic coefficient and high-order aspherical terms, to improve the collimation capability of the large divergence angle light beam in the fast axis direction.

[0006] According to an embodiment of the present disclosure, the surface type expression of the aspherical cylindrical mirror surface is:

[0007]

[0008] wherein, represents the profile height of the optical surface in the fast axis direction, is an off-axis coordinate in the fast axis direction, R is a radius of curvature in the fast axis direction, K is a conic constant, , , , is a high-order aspheric coefficient, and n is a positive integer.

[0009] According to the embodiment of the present disclosure, the effective aperture of the aspheric cylindrical lens surface is greater than a preset size to match the collection requirement of the high numerical aperture beam in the fast axis direction, and the long back focal length parameter is combined to realize the compression and collimation of the large divergence angle beam, wherein the preset size is 5nm-10nm.

[0010] According to the embodiment of the present disclosure, the divergence angle of the slow axis direction of the divergent light after the spherical cylindrical lens surface expansion shaping is greater than 90°.

[0011] According to the embodiment of the present disclosure, the outer edge of the first surface of the lens is provided with symmetrical non-optical edge areas which do not participate in the transmission of the light beam and are used for realizing the anti-edge collapse, mechanical positioning and structural support; the width of the non-optical edge area is 0.3mm-1mm.

[0012] According to the embodiment of the present disclosure, the monolithic optical glass is an optical glass with high refractive index.

[0013] Another aspect of the embodiment of the present disclosure provides a semiconductor laser array, comprising: a plurality of edge-emitting semiconductor lasers arranged in a line; a composite lens integrally mounted at the front end of the plurality of edge-emitting semiconductor lasers; the composite lens is an integrated composite cylindrical lens of the embodiment of the present disclosure.

[0014] According to the embodiment of the present disclosure, the plurality of edge-emitting semiconductor lasers arranged in a line are arranged at equal intervals or non-equal intervals, wherein the plurality of edge-emitting semiconductor lasers arranged at equal intervals are used to optimize the light intensity distribution of the outgoing light beam in the slow axis direction and improve the irradiation uniformity or energy distribution control ability.

[0015] According to the embodiment of the present disclosure, the initial divergence angle of the edge-emitting semiconductor laser is about 30°-70°, and the slow axis direction divergence angle is about 6°-14°; the edge-emitting semiconductor laser includes a Fabry-Perot type laser or an edge-emitting chip, the active region structure of the Fabry-Perot type laser can include a tunnel junction structure or a tapered amplification structure, and the edge-emitting chip has a wide strip or ridge waveguide structure.

[0016] The integrated composite cylindrical lens for the edge-emitting semiconductor laser array and the semiconductor laser array provided by the present disclosure have at least the following technical effects:

[0017] The composite lens is formed by single glass processing, can be integrally installed in front of the linear array of the laser, does not need to paste FAC for each chip, significantly improves the fast-axis collimation consistency, forms continuous controllable angular divergence in the slow-axis direction, is compact in size, is easy to assemble and adjust, and is suitable for batch integration of high-density edge-emitting laser array systems.

[0018] The composite lens is a glass lens with bidirectional cylindrical curvature composed of front and rear orthogonal cylindrical mirror surfaces. The front surface is a cylindrical mirror surface with negative spherical curvature along the slow-axis direction, used to realize large-angle expansion of the laser array in the slow-axis direction under the premise of maintaining linear arrangement of the chips, and significantly improve the horizontal angle coverage range. The rear surface is a cylindrical mirror surface with aspherical profile along the fast-axis direction, used to realize compression and collimation of the large-divergence-angle beam in the fast-axis direction, and improve the beam consistency and direction control precision.

[0019] Simulation results show that the composite lens can compress the fast-axis divergence angle of the semiconductor laser to within 0.6°, while expanding the divergence angle in the slow-axis direction to more than 90° horizontally, meets the requirements of the laser array in wide-angle output, linear emission, wide-field detection and other application scenarios, and has good engineering practicability and popularization value. BRIEF DESCRIPTION OF DRAWINGS

[0020] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure, taken in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A three-dimensional schematic view of the integrated composite lens structure according to an embodiment of the present disclosure is schematically shown.

[0022] Figure 2 A top view of the integrated composite lens structure according to an embodiment of the present disclosure is schematically shown.

[0023] Figure 3 A front view of the integrated composite lens structure according to an embodiment of the present disclosure is schematically shown.

[0024] Figure 4A A path schematic view of the light rays in the slow-axis direction passing through the lens to form large-angle divergence and a light source linear arrangement schematic view according to an embodiment of the present disclosure are schematically shown.

[0025] Figure 4B A horizontal coverage angle calculation result view according to an embodiment of the present disclosure is schematically shown.

[0026] Figure 5A A schematic view of the light rays in the fast-axis direction passing through the lens to realize collimation compression according to an embodiment of the present disclosure is schematically shown.

[0027] Figure 5BThe calculation results of the divergence angle of the light rays in the fast axis direction collimated by the lens are schematically shown. DETAILED DESCRIPTION

[0028] Embodiments of the present disclosure will be described below with reference to the accompanying drawings. It should be understood, however, that the description that follows is merely exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description of embodiments of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that one or more embodiments can be practiced without these specific details. In other instances, well-known structures and functions have not been described in detail in order to avoid obscuring aspects of the present disclosure.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the term "includes" and tautological expressions thereof, such as "including," "includes," "include," "contains," "containing," and so forth, mean the term "comprises," as long as the above-mentioned features, steps, operations, and / or components are present.

[0030] All terms used herein, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of the specification, and should not be interpreted in an idealized or overly formal manner.

[0031] Embodiments of the present disclosure provide an integrated compound cylindrical lens for edge-emitting semiconductor laser arrays and a semiconductor laser array. The compound lens is an integrated lens structure that is adapted to linearly arranged lasers, and can simultaneously achieve fast axis compression and slow axis angular expansion in a monolithic piece, thereby simplifying optical path design, improving system compactness, and improving assembly efficiency.

[0032] Figure 1 A three-dimensional schematic view of an integrated compound lens structure according to an embodiment of the present disclosure is schematically shown. Figure 2 A top view of an integrated compound lens structure according to an embodiment of the present disclosure is schematically shown. Figure 3 A front view of an integrated compound lens structure according to an embodiment of the present disclosure is schematically shown.

[0033] As Figures 1-3As shown, the composite lens for fast-axis collimation and slow-axis expansion in the embodiment can include a lens formed by processing a single piece of optical glass. Among them, the first surface 1 (front surface) of the lens is a spherical cylindrical mirror surface, the cylinder axis of the spherical cylindrical mirror surface is parallel to the fast-axis direction, and is used for expanding and shaping the divergent light in the slow-axis direction. The second surface 2 (back surface) of the lens is a non-spherical cylindrical mirror surface, the cylinder axis of the non-spherical cylindrical mirror surface is parallel to the slow-axis direction, and is used for compressing and collimating the large divergence angle light beam in the fast-axis direction. The first surface 1 and the second surface 2 are oppositely arranged, and form a composite cylindrical optical structure with different curvatures in the fast and slow axis directions, to realize the synchronous shaping of the biaxial light beam.

[0034] In some embodiments, the surface type parameters of the non-spherical cylindrical mirror surface include a negative curvature, a conic coefficient, and a high-order non-spherical surface term, for improving the collimation capability of the large divergence angle light beam in the fast-axis direction.

[0035] Further, the surface type expression of the non-spherical cylindrical mirror surface is:

[0036]

[0037] Among them, represents the profile height of the optical surface in the fast-axis direction, is the off-axis coordinate in the fast-axis direction, R is the curvature radius in the fast-axis direction, and K is the conic coefficient, , , , …, the high-order non-spherical surface coefficient is used to further correct the surface type. n is a positive integer.

[0038] In some embodiments, the effective light transmission aperture of the non-spherical cylindrical mirror surface is greater than a preset size to match the collection requirement of the high numerical aperture light beam in the fast-axis direction, and in combination with the long back focal length parameter, the compression and collimation of the large divergence angle light beam are realized. Among them, the preset size is 5nm~10nm.

[0039] In some embodiments, the divergence angle of the divergent light in the slow-axis direction after being expanded and shaped by the spherical cylindrical mirror surface is greater than 90°.

[0040] In some embodiments, the outer edge of the first surface of the lens is provided with symmetrical non-optical edge areas, the non-optical edge areas do not participate in light beam transmission, and are used to realize anti-edge collapse, mechanical positioning and structural support; the width of the non-optical edge area is 0.3 mm~1mm.

[0041] In some embodiments, the single piece of optical glass is an optical glass with high refractive index.

[0042] Based on the composite lens, the embodiment of the present disclosure further provides a semiconductor laser array, comprising: a plurality of edge-emitting semiconductor lasers arranged linearly; a composite lens integrally mounted at the front end of the plurality of edge-emitting semiconductor lasers; and the composite lens is the integrated composite cylindrical lens as described above.

[0043] In some embodiments, the plurality of edge-emitting semiconductor lasers arranged linearly are arranged at equal intervals or at unequal intervals, wherein the plurality of edge-emitting semiconductor lasers arranged at equal intervals are used to optimize the light intensity distribution of the outgoing light beam in the slow-axis direction, and improve the illumination uniformity or energy distribution control capability.

[0044] In some embodiments, the initial divergence angle of the edge-emitting semiconductor laser is about 30°-70°, and the divergence angle in the slow-axis direction is about 6°-14°; the edge-emitting semiconductor laser comprises a Fabry-Perot type laser or an edge-emitting chip, the active region structure of the Fabry-Perot type laser can comprise a tunnel junction structure or a tapered amplification structure, and the edge-emitting chip has a wide strip or ridge waveguide structure.

[0045] In order to more clearly illustrate the advantages of the integrated composite cylindrical lens for the edge-emitting semiconductor laser array and the semiconductor laser array provided by the embodiments of the present disclosure, a specific example is provided below for illustration.

[0046] In this example, the composite lens is an integrated optical element for a 905 nm waveband edge-emitting semiconductor laser array, and its core function is to realize large-angle divergence compression collimation in the fast-axis direction and large-angle beam expansion in the slow-axis direction.

[0047] The lens is integrally processed from optical glass and has two orthogonal cylindrical surfaces in front and back. The front surface is a cylindrical optical surface with spherical curvature (the curved surface 10 of the first surface), and the curvature is along the horizontal (slow-axis) direction. In this embodiment, the curvature is set to -6.6 mm. The center point of the curved surface of the front surface of the integrated lens is 4.98 mm away from the light source, the total thickness of the lens is 11.98 mm, the height is 6.5 mm, and the effective focal length of the system is 34.5 mm. To ensure that the subsequent fast-axis large-divergence-angle light rays can effectively enter the lens, the radial height of the composite lens is designed to be 13 mm. The composite lens has a lateral size of 16 mm to cover the entire laser linear array arrangement, ensuring that each light-emitting unit is effectively affected by the optical surface, thereby realizing overall fast-slow-axis beam shaping.

[0048] To improve the mechanical stability and edge damage resistance of the composite lens in the actual assembly process, in the example, the front surface of the composite lens is provided with symmetrically distributed non-optical areas 11 on both sides of the front surface, which are located at the edges of the front surface of the lens and do not participate in the transmission and shaping of the laser beam. The typical width is 0.3mm~1mm, which is continuously processed by the same material as the optical area. The surface of the area can be designed as a smooth plane or a chamfered transition curve.

[0049] In the example, 8 edge-emitting tunnel junction lasers are configured, linearly arranged along the horizontal direction at a pitch of 1.2mm, and the initial slow-axis direction divergence angle of each is 10° (1 / e 2 Light intensity definition).

[0050] Figure 4A The path diagram of the slow-axis direction light passing through the lens to form a large-angle divergence and the linear arrangement diagram of the light source are schematically shown according to the embodiment of the present disclosure.

[0051] Figure 4B The horizontal coverage angle calculation result diagram according to the embodiment of the present disclosure is schematically shown.

[0052] As shown in Figure 4A and Figure 4B , the front surface of the composite lens is used to expand the outgoing light beam of each laser into a fan-shaped divergence in the horizontal direction, and the overall horizontal angle coverage is 95°. To improve the uniformity of the light intensity distribution of the outgoing light beam in the slow-axis direction, the edge-emitting laser array can adopt a non-equidistant linear arrangement method, that is, the spacing of each light-emitting unit in the horizontal direction is optimized and adjusted according to the target irradiation distribution, instead of using a fixed spacing arrangement.

[0053] The rear surface is a non-spherical cylindrical mirror surface with curvature along the vertical (fast-axis) direction. In the example, the non-spherical cylindrical mirror surface adopts the following expression:

[0054]

[0055] wherein the curvature radius R is set to -7.43mm, the conic coefficient K is -0.41mm, , , -8.13E-04, -1.24E-05, -9.43E-08, respectively.

[0056] In the example, a 905nm tunnel junction laser with 3 active regions is used, each active region has a thickness of 300nm, the spacing of the active regions is 5um, and the initial fast-axis divergence full angle is 50°.

[0057] Figure 5AA schematic diagram of collimation compression of light rays in the fast axis direction after passing through the lens is shown. Figure 5B A schematic diagram of the calculation results of the divergence angle of light rays in the fast axis direction after collimation through the lens is shown.

[0058] As shown in Figure 5A and Figure 5B The angular space distribution ranges from -0.3° to 0.3°, i.e., the remaining divergence angle after collimation is 0.6°.

[0059] The above describes embodiments of the present disclosure. However, these embodiments are merely for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. An integrated compound cylindrical lens for an edge-emitting semiconductor laser array, characterized by, Comprise: a lens formed by processing a single piece of optical glass; wherein the first surface of the lens is a spherical cylindrical mirror surface, the cylindrical axis of the spherical cylindrical mirror surface is parallel to the fast axis direction, and the spherical cylindrical mirror surface is used to expand and shape a divergent light beam in the slow axis direction; the second surface of the lens is a non-spherical cylindrical mirror surface, the cylindrical axis of the non-spherical cylindrical mirror surface is parallel to the slow axis direction, and the non-spherical cylindrical mirror surface is used to compress and collimate a large divergence angle light beam in the fast axis direction; the first surface and the second surface are oppositely arranged and form a composite cylindrical optical structure with different curvatures in the fast and slow axis directions, realizing synchronous shaping of a biaxial light beam.

2. The one-piece compound cylindrical lens of claim 1, wherein The surface type parameters of the non-spherical cylindrical mirror surface include negative curvature, conic coefficient, and high-order non-spherical surface terms, which are used to improve the collimation ability of the large divergence angle light beam in the fast axis direction.

3. The one-piece compound cylindrical lens of claim 2, wherein, The surface type expression of the non-spherical cylindrical mirror surface is: wherein represents a profile height of the optical surface in the fast axis direction, is an off-axis coordinate in the fast axis direction, R is a radius of curvature in the fast axis direction, and K is a conic constant, , , ,..., high-order aspherical coefficients, n is a positive integer.

4. The one-piece compound lenticular lens according to any one of claims 1 to 3, wherein The effective light transmission aperture of the non-spherical cylindrical mirror surface is greater than a preset size to match the collection requirements of a high numerical aperture light beam in the fast axis direction, and in combination with a long back focal length parameter, the non-spherical cylindrical mirror surface realizes compression and collimation of a large divergence angle light beam, and the preset size is 5nm-10nm.

5. The one-piece compound lenticular lens of claim 1, wherein, The divergence angle of the divergent light in the slow axis direction after being expanded and shaped by the spherical cylindrical mirror surface is greater than 90°.

6. The one-piece compound lenticular lens of claim 1, wherein, The outer edge of the first surface of the lens is provided with symmetrical non-optical edge regions, the non-optical edge regions do not participate in light beam transmission, and are used to realize anti-edge collapse, mechanical positioning, and structural support; the width of the non-optical edge region is 0.3mm-1mm.

7. The one-piece compound lenticular lens of claim 1, wherein, The single piece of optical glass is an optical glass with high refractive index.

8. A semiconductor laser array, characterized by, Comprise: a plurality of edge emitting semiconductor lasers arranged linearly; a composite lens integrally mounted at the front end of the plurality of edge emitting semiconductor lasers; The composite lens is an integrated composite cylindrical lens according to any one of claims 1-7.

9. The semiconductor laser array of claim 8, wherein, The plurality of edge emitting semiconductor lasers arranged linearly are arranged at equal intervals or at unequal intervals, wherein the plurality of edge emitting semiconductor lasers arranged at equal intervals are used to optimize the light intensity distribution of the outgoing light beam in the slow axis direction and improve the irradiation uniformity or energy distribution control ability.

10. The semiconductor laser array of claim 8 or 9, wherein, The initial divergence angle of the edge emitting semiconductor laser is about 30°-70°, and the divergence angle in the slow axis direction is about 6°-14°; The edge emitting semiconductor laser comprises a Fabry-Perot type laser or an edge emitting chip, the active region structure of the Fabry-Perot type laser can comprise a tunnel junction structure or a tapered amplification structure, and the edge emitting chip has a wide strip or ridge waveguide structure.

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