Beam-splitting packaging structure of semiconductor lasers

Abstract

This invention provides a beam-splitting packaging structure for a semiconductor laser. The beam-splitting packaging structure includes: a base and a semiconductor laser connected to the base; a packaging frame, the packaging frame and the base being sealed together to form a sealed cavity, so that the semiconductor laser is located in the sealed cavity, the packaging frame including opposing sidewalls opposite to the semiconductor laser; a lens structure, the lens structure being integrally formed with the packaging frame, the lens structure protruding from the inside of the opposing sidewall toward the semiconductor laser and located in the sealed cavity; and a diffractive optical element, the diffractive optical element being disposed on the outside of the opposing sidewall and located outside the sealed cavity; wherein, the laser beam emitted by the semiconductor laser is collimated in the lens structure, and then split by the diffractive optical element to form multiple parallel beams for emission.

Description

Technical Field

[0001] This invention relates to the field of atomic physics, and in particular to a beam-splitting packaging structure for a semiconductor laser. Background Technology

[0002] The technology of manipulating atomic quantum state changes to study and precisely measure atomic physical properties can be applied in various fields such as quantum communication, atomic clocks, atomic gravimeters, and quantum simulation. These applications involve the interaction between lasers and atoms. Considering that some applications require multiple laser beams to interact with atoms, current methods employ laser beam splitting. However, existing technologies have not addressed how to split semiconductor laser beams for use in the physical scenarios of atomic transitions.

[0003] Furthermore, current laser beam splitting technologies often employ polarization beam splitters, resulting in complex optical paths and requiring numerous optical components and devices. If beam splitters or coated beam splitting solutions are used, the optical system is susceptible to temperature fluctuations, leading to poor stability. Additionally, these beam splitters can introduce additional optical path differences, which can cause phase differences when interacting with atomic (or molecular) systems, thus affecting the noise level of the detection.

[0004] Therefore, it is necessary to propose a packaging structure based on semiconductor laser beam splitting that can be used for detection in physical scenarios of atomic transitions. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a beam-splitting packaging structure for a semiconductor laser.

[0006] This invention provides a beam-splitting packaging structure for a semiconductor laser, comprising: a base and a semiconductor laser connected to the base; a packaging frame, wherein the packaging frame and the base are sealed together to form a sealed cavity, such that the semiconductor laser is located within the sealed cavity, the packaging frame including opposing sidewalls opposite to the semiconductor laser; a lens structure integrally formed with the packaging frame, the lens structure protruding from the inner side of the opposing sidewall toward the semiconductor laser and located within the sealed cavity; and a diffractive optical element disposed on the outer side of the opposing sidewall and located outside the sealed cavity; wherein the laser beam emitted by the semiconductor laser is collimated in the lens structure and then split by the diffractive optical element to form multiple parallel beams for emission.

[0007] As an optional technical solution, the diffractive optical element is fixed to the outer side of the opposing sidewall by optical adhesive.

[0008] As an optional technical solution, a microlens array is provided on the side of the diffractive optical element away from the opposing sidewall. The microlens array is used to collimate the multiple parallel beams emitted from the diffractive optical element before they are emitted.

[0009] As an optional technical solution, the opposing sidewall includes a raised portion, the top of which protrudes from the inner side of the opposing sidewall in the area where the raised portion is not provided, and the lens structure is provided on the top of the raised portion; wherein, the encapsulation frame, the raised portion and the lens structure are integrally formed.

[0010] As an optional technical solution, the packaging frame and the base are pressure welded together to form the sealed chamber.

[0011] As an optional technical solution, the diffractive optical element is provided with an isolation layer and a light-shielding part in sequence on the side away from the opposing sidewall, and the light-shielding part only blocks a local area of ​​the light emitting surface of the isolation layer.

[0012] As an optional technical solution, the light-shielding part is disposed at the center of the isolation layer.

[0013] As an optional technical solution, the isolation layer is a glass isolation layer.

[0014] As an optional technical solution, the beam splitting element has a preset beam splitting angle θ, and the isolation layer has a preset thickness t, wherein the width l of the light-shielding part is less than 2t*tanθ / 2.

[0015] As an optional technical solution, the lens structure is a convex lens.

[0016] Compared with existing technologies, the present invention provides a beam-splitting packaging structure for a semiconductor laser, which encapsulates the semiconductor laser and a packaging frame including optical lenses and beam-splitting elements to form a packaging structure, enabling collimation and beam splitting of the semiconductor laser. The aforementioned beam-splitting packaging structure for the semiconductor laser has the following technical advantages:

[0017] 1. Diffractive optical elements (DOEs) are small in size and weight, have a simple optical path structure, and require fewer optical components in their beam splitting and packaging structures. The microlens arrays used in DOEs are more miniaturized, convenient, lightweight, and highly integrated compared to traditional optical elements.

[0018] 2. Flexibility: Thanks to the significant advancements in micro-nano fabrication technology, DOEs can be customized for different lasers or different target light intensity / phase distributions.

[0019] 3. It occupies little space, is easy to implement, and has no polarization beam splitter, so the parallel light after beam splitting is not affected by optical path difference.

[0020] 4. By using a stacked optical element approach, the collimation requirement of the beam can be directly achieved internally, avoiding the influence of the external environment on the optical path. The beam stability is improved, resulting in more accurate detection results in physical scenarios involving atomic transitions. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a cross-sectional schematic diagram of the beam-splitting packaging structure of a semiconductor laser according to an embodiment of the present invention;

[0023] Figure 2 This is a cross-sectional schematic diagram of the beam-splitting packaging structure of a semiconductor laser according to another embodiment of the present invention;

[0024] Figure 3 This is a cross-sectional schematic diagram of the beam-splitting packaging structure of a semiconductor laser in another embodiment of the present invention;

[0025] Figure 4 for Figure 3 A schematic diagram showing the arrangement of diffractive optical elements, isolation layers, and light-shielding layers in the middle.

[0026] Figure 5 This is a cross-sectional schematic diagram of the beam-splitting packaging structure of a semiconductor laser in another embodiment of the present invention;

[0027] Figure 6 This is a cross-sectional schematic diagram of the beam-splitting packaging structure of a semiconductor laser in another embodiment of the present invention. Detailed Implementation

[0028] To provide a further understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0029] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] like Figure 1 As shown, the present invention provides a beam-splitting packaging structure for a semiconductor laser, comprising: a base 20 and a semiconductor laser 30 connected to the base 20; a packaging frame 10, wherein the packaging frame 10 and the base 20 are sealed together to form a sealed cavity 70, so that the semiconductor laser 30 is located in the sealed cavity 70, the packaging frame 10 including opposing sidewalls 12 opposite to the semiconductor laser 30; a lens structure 11, the lens structure 11 being integrally formed with the packaging frame 10, the lens structure 11 protruding from the inner side of the opposing sidewall 12 toward the semiconductor laser 30 and located in the sealed cavity 70; and a diffractive optical element 40, the diffractive optical element 40 being disposed on the outer side of the opposing sidewall 12 and located outside the sealed cavity 70; wherein, the laser beam emitted by the semiconductor laser 30 is collimated in the lens structure 11, and then split by the diffractive optical element 40 to form multiple parallel beams emitted.

[0031] In this embodiment, the packaging frame 10 and the lens structure 11 are integrally formed, and the diffractive optical element 40 is fixed to the outer side of the opposite sidewall 12 of the packaging frame 10 by optical adhesive, so that the overall volume of the beam splitting packaging structure using semiconductor laser 30 is small.

[0032] In one embodiment, the semiconductor laser 30 is a semiconductor laser chip; the diffractive optical element 40 is a DOE diffraction beam splitter, which splits the beam by changing the phase of the propagating light passing through the DOE diffraction beam splitter through the microstructure pattern fabricated on the substrate material. It is understood that the microstructure pattern on the surface of the DOE diffraction beam splitter can be customized according to actual beam splitting needs. Therefore, this allows the application scenarios of the semiconductor laser beam splitting packaging structure of the present invention to be customized with different DOE diffraction beam splitters according to actual beam splitting needs, providing flexibility in use.

[0033] Furthermore, based on the properties of laser beams, the smaller the beam waist, the larger the divergence angle. In this embodiment, the semiconductor laser 30 is taken as a VCSEL semiconductor laser. The beam of a VCSEL semiconductor laser exhibits conical divergence, with a divergence angle reaching approximately 20 degrees. Therefore, a lens structure 11 is added to the exit path of the laser beam. The lens structure 11 is used to shape and collimate the laser beam, increase its beam waist, reduce its divergence angle, and enable the laser beam to obtain a longer Rayleigh distance, thus giving the collimated beam good collimation.

[0034] As described above, the lens structure 11 is used to collimate the laser beam of the semiconductor laser 30, controlling the divergence angle of the laser beam to be smaller than that of the DOE diffraction beam splitter, thus avoiding the situation where the DOE diffraction beam splitter cannot separate the laser beam. Therefore, in this embodiment, placing the lens structure 11 between the semiconductor laser 30 and the DOE diffraction beam splitter (or diffractive optical element 40) is one of the necessary conditions for obtaining multiple parallel laser beams. In particular, for physical scenarios involving atomic transitions, multiple parallel laser beams are effective in improving the detection accuracy of such scenarios.

[0035] In another embodiment of the invention, a convex lens and a microlens array are sequentially arranged on the side of the diffractive optical element 40 away from the opposing sidewall 11. The convex lens and microlens array are used to collimate the multiple laser beams emitted from the diffractive optical element twice, resulting in parallel emission. The convex lens is used to change the direction of the principal optical axis of the split beam, performing secondary shaping of the laser beam to make the principal optical axes of the beams parallel. Then, the microlens array further shapes the diverged beams after secondary shaping. Thus, the obtained laser beams have good collimation and high parallelism, meeting the requirements.

[0036] In other embodiments of the present invention, a microlens array is sequentially arranged on the side of the diffractive optical element 40 away from the opposing sidewall 11, and a convex lens is arranged after the microlens array. The laser beam after beam splitting emitted from the diffractive optical element 40 is collimated and the emission direction is changed multiple times by the microlens array and the convex lens, thereby controlling the collimation of the laser beam after beam splitting to meet the requirements of use in the physical scenario of atomic transition.

[0037] It is understandable that the aforementioned microlens array and convex lens can be fixed to the rear of the diffractive optical element 40 away from the opposing sidewall 11 using optical adhesive. The spacing between the microlens array and the convex lens and the diffractive optical element 40 is adjusted by adding an isolation layer. The isolation layer can be, for example, a transparent isolation layer, including but not limited to a transparent glass isolation layer.

[0038] Continue to refer to Figure 1Ideally, the laser emitted from the semiconductor laser 30 is split by the diffractive optical element 40 and then needs to be shaped by another convex lens 80. Before the beam diverges after the second shaping, there is a Rayleigh distance. Within this Rayleigh distance, the laser beam has high collimation and parallelism. When applied to the detection of physical scenes of atomic transitions, if the interaction distance between the laser beam and the atom is within this distance, no other optical elements need to be added to the atomic detection device.

[0039] like Figure 1 As shown, in the beam-splitting packaging structure of a semiconductor laser, the laser beam from the semiconductor laser 30 needs to be shaped and collimated before beam splitting. Therefore, after the laser beam is first shaped by the lens structure 11 in the packaging structure, the laser divergence angle must be smaller than the dispersion angle of the optical diffraction element 40, and cannot exceed the dispersion angle of the diffraction optical element 40, in order to achieve ideal collimation into parallel light. Therefore, the lens structure 11 needs to be placed close to the semiconductor laser 30. The lens structure 11 is a convex lens. After the laser beam is shaped, the convex lens controls the laser beam to have a smaller spot size when incident on the optical diffraction element 40, thus resulting in a smaller spot size when the laser beam exits from the optical diffraction element 40, which is beneficial for laser beam splitting.

[0040] In this embodiment, the lens structure 11 and the packaging frame 10 are integrally formed, for example, by compression molding. The packaging frame 10 and the base 20 of the semiconductor laser 30 are packaged together by pressure welding to complete the packaging of the semiconductor laser 30 and the packaging frame 10. The diffractive optical element 40 can be pre-fixed to the opposite sidewall 12 of the packaging frame 10 to form a pre-packaged body, which is then packaged with the base of the semiconductor laser 30 to form a sealed cavity 70. Thus, the semiconductor laser 30 packaging achieves beam splitting using the diffractive optical element 40, and, depending on actual needs, the base 20 can be made of glass. This packaging structure, in addition to achieving beam splitting, also possesses non-magnetic characteristics.

[0041] Understandably, the laser emitted from the semiconductor laser 30 needs to be refracted by a convex lens (lens structure 11) and then travel a certain distance before entering the optical diffraction element 40 for beam splitting. Therefore, the thickness of the opposing sidewall 12 of the frame 10 can be set according to this exit distance, and the thickness of the opposing sidewall 12 can be controlled to be approximately equal to the exit distance. The laser beam refracted by the convex lens is then emitted into the optical diffraction element 40 to achieve laser beam splitting.

[0042] like Figure 2 As shown, in order to adjust the thickness of the opposing sidewall 12 and avoid increasing the volume of the encapsulation frame 10, the opposing sidewall 12 includes a raised portion 13. The top of the raised portion 13 protrudes into the area inside the opposing sidewall 11 where no raised portion is provided. The lens structure 11 is provided on the top of the raised portion 13. The encapsulation frame 10, the raised portion 13 and the lens structure 11 are integrally formed.

[0043] like Figure 5 As shown, in other embodiments of the present invention, a concave lens 90 may be provided on the side of the diffractive optical element 40 away from the opposing sidewall 12. The concave lens 90 is used to separate the laser beam after it has been split by the diffractive optical element 40, and to expand the separation angle of the split laser beam before it is emitted.

[0044] like Figure 6 As shown, a convex lens 91 can be added to the side of the concave lens 90 away from the diffractive optical element 40. The convex lens 91 is used to reshape the laser beam emitted from the concave lens 90 before it is emitted again to form a parallel split laser beam.

[0045] like Figure 3 As shown, the diffractive optical element 40 has an isolation layer 50 and a light-shielding part 60 arranged sequentially on the side away from the opposing sidewall 12. The light-shielding part 60 only blocks a local area of ​​the light emitting surface of the isolation layer 50.

[0046] In this embodiment, the light-shielding part 60 blocks the center of the isolation layer 50; the isolation layer 50 is a glass isolation layer.

[0047] The isolation layer 50 and the light-shielding layer 60 are mainly designed to meet the needs of the physical scene. Since a central laser beam splitting is not required, the light-shielding layer 60 is used to block different areas, allowing the laser beam emitted from different regions to be split. For example, when a central laser beam splitting is not needed, the laser beam splitting in the central area can be blocked.

[0048] like Figure 3 and Figure 4 As shown, since the separation distance between laser beams is small when the laser is emitted to the upper surface of the diffractive optical element 40, it is difficult to perform shielding. Therefore, a glass isolation layer with a certain thickness is added above the diffractive optical element 40, and then the light-shielding layer 60 used for shielding is placed above the glass isolation layer.

[0049] The relationship between the width l of the light-shielding layer 60 and the thickness h of the glass is as follows: the beam splitting element has a preset beam splitting angle θ, and the isolation layer has a preset thickness t, wherein the width l of the light-shielding part is less than 2t*tanθ / 2.

[0050] Taking a diffractive optical element 40 with a resolution of 10° as an example, l < 2h * tan5°, the diffractive optical element 40 and the glass isolation layer 50, and the glass isolation layer 50 and the light-shielding layer 60 are respectively fixedly connected by optical adhesive.

[0051] In other embodiments of the present invention, the light-shielding layer 60 may also be a light-shielding pattern printed on the isolation layer 50.

[0052] The beam splitting packaging structure of the semiconductor laser provided by the present invention is compatible with existing TO (Transisitor Outline) packaging and QFN (QuadFlat No-leads Package) packaging processes because it adopts a packaging frame and a semiconductor laser base packaging method.

[0053] This invention provides a beam-splitting packaging structure for a semiconductor laser. The structure encapsulates the semiconductor laser and a packaging frame including optical lenses and beam-splitting elements, enabling collimation and beam splitting of the semiconductor laser. This beam-splitting packaging structure for the semiconductor laser offers the following technical advantages:

[0054] 1. Diffractive optical elements (DOEs) are small in size and weight, have a simple optical path structure, and require fewer optical components in their beam splitting and packaging structures. The microlens arrays used in DOEs are more miniaturized, convenient, lightweight, and highly integrated compared to traditional optical elements.

[0055] 2. Flexibility: Thanks to the significant advancements in micro-nano fabrication technology, DOEs can be customized for different lasers or different target light intensity / phase distributions.

[0056] 3. It occupies little space, is easy to implement, and has no polarization beam splitter, so the parallel light after beam splitting is not affected by optical path difference.

[0057] 4. By using a stacked optical element approach, the collimation requirement of the beam can be directly achieved internally, avoiding the influence of the external environment on the optical path. The beam stability is improved, resulting in more accurate detection results in physical scenarios involving atomic transitions.

[0058] The present invention has been described by the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. Furthermore, the technical features involved in the different embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A beam-splitting packaging structure for a semiconductor laser, used for detecting physical scenes of atomic transitions, characterized in that, The beam-splitting packaging structure of the semiconductor laser includes: A base and a semiconductor laser connected to the base, wherein the semiconductor laser is a semiconductor laser chip; A packaging frame and a base are sealed together to form a sealed chamber, so that the semiconductor laser is located in the sealed chamber, and the packaging frame includes opposing sidewalls opposite to the semiconductor laser; A lens structure, integrally formed with the packaging frame, the lens structure protruding from the inside of the opposing sidewall toward the semiconductor laser and located within the sealed cavity; and A diffractive optical element is disposed on the outside of the opposing sidewall and located outside the sealed cavity; the diffractive optical element is fixed on the outside of the opposing sidewall; the diffractive optical element is a DOE diffraction beam splitter, which changes the phase of the propagating light passing through the DOE diffraction beam splitter by using a microstructure pattern fabricated on the substrate material, thereby splitting the laser beam for output. The lens structure is located close to the semiconductor laser and on the exit path of the laser beam emitted by the semiconductor laser. The laser beam emitted by the semiconductor laser is collimated directly in the lens structure and then split by the DOE diffractometer to form multiple parallel beams for exit. The opposing sidewall also includes a raised portion, the top of which protrudes from the inner side of the opposing sidewall in the area where the raised portion is not provided. The lens structure is provided with the top of the raised portion. The raised portion adjusts the thickness of the opposing sidewall. The thickness of the opposing sidewall is equal to the emission distance required after the laser beam emitted by the semiconductor laser is collimated by the lens structure.

2. The beam-splitting packaging structure of the semiconductor laser as described in claim 1, characterized in that, The diffractive optical element is fixed to the outer side of the opposing sidewall by optical adhesive.

3. The beam-splitting packaging structure of the semiconductor laser as described in claim 1, characterized in that, The diffractive optical element is provided with a microlens array on the side away from the opposing sidewall. The microlens array is used to collimate the multiple parallel beams emitted from the diffractive optical element twice before they are emitted.

4. The beam-splitting packaging structure of the semiconductor laser as described in claim 1, characterized in that, The encapsulation frame, the raised portion, and the lens structure are integrally formed.

5. The beam-splitting packaging structure of the semiconductor laser as described in claim 1, characterized in that, The encapsulation frame and the base are welded together to form the sealed chamber.

6. The beam-splitting packaging structure of the semiconductor laser as described in claim 1, characterized in that, The diffractive optical element has an isolation layer and a light-shielding part arranged sequentially on the side away from the opposing sidewall, and the light-shielding part only blocks a local area of ​​the light emitting surface of the isolation layer.

7. The beam-splitting packaging structure of the semiconductor laser as described in claim 6, characterized in that, The light-shielding part is located at the center of the isolation layer.

8. The beam-splitting packaging structure of the semiconductor laser as described in claim 6, characterized in that, The isolation layer is a glass isolation layer.

9. The beam-splitting packaging structure of the semiconductor laser as described in claim 6, characterized in that, The beam splitting element has a preset beam splitting angle θ, and the isolation layer has a preset thickness t, wherein the width l of the light-shielding part is less than 2t*tanθ / 2.

10. The beam-splitting packaging structure of the semiconductor laser as described in claim 1, characterized in that, The lens structure is a convex lens.

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