Vertical cavity surface emitting laser device

Abstract

Embodiments of this disclosure include a vertical-cavity surface-emitting laser device comprising a mesa having a non-circular cross-section. Embodiments also include multiple layers having one or more oxide layers. Embodiments may further include one or more non-oxide layers. The mesa may function as a dielectric top mirror.

Description

Technical Field

[0001] This disclosure generally relates to vertical cavity surface-emitting laser devices. Background Technology

[0002] Various aspects of this invention relate to vertical-cavity surface-emitting laser (VCSEL) devices. Conventional VCSEL devices may have various problems. Therefore, conventional VCSEL devices can be expensive, bulky, and / or inefficient.

[0003] The limitations and disadvantages of conventional systems and methods will become apparent to those skilled in the art by comparing such methods with some aspects of the present methods and systems illustrated in the remainder of this disclosure with reference to the accompanying drawings. Summary of the Invention

[0004] As shown and / or described in combination with at least one of these figures, and as set forth more fully in the claims, is a vertical-cavity surface-emitting laser device.

[0005] These and other advantages, aspects and novel features of this disclosure, as well as details of the embodiments shown therein, will be more fully understood from the following description and accompanying drawings. Attached Figure Description

[0006] The various features and advantages of the invention can be more readily understood by referring to the following detailed description taken in conjunction with the accompanying drawings, wherein the same reference numerals denote the same structural elements.

[0007] Figure 1A This is a block diagram illustrating a vertical cavity surface-emitting laser device according to some embodiments of the present disclosure.

[0008] Figure 1B This disclosure describes an exemplary embodiment of a vertical-cavity surface-emitting laser device 100.

[0009] Figure 2A This further illustrates some embodiments according to the present disclosure. Figure 1A Block diagram of a vertical cavity surface-emitting laser device.

[0010] Figure 2B An exemplary disclosure of a laser device 100 having an elliptical cross section 112 according to some embodiments of the present disclosure is shown.

[0011] Figure 2C An exemplary disclosure of a laser device 100 having a concentric elliptical annular cross section 112 / 213 according to some embodiments of the present disclosure is shown.

[0012] Figure 2D and Figure 2EAn exemplary non-circular cross section 112 is shown according to various embodiments of the present disclosure.

[0013] Figure 3A This further illustrates some embodiments according to the present disclosure. Figure 1A Block diagram of a vertical cavity surface-emitting laser device.

[0014] Figure 3B This is an exemplary embodiment of the present disclosure that includes multiple pairs of reflectors.

[0015] Figure 3C This is an exemplary embodiment of the present disclosure that includes multiple pairs of reflectors. Detailed Implementation

[0016] The following discussion provides various examples of vertical-cavity surface-emitting laser devices. Such examples are non-limiting, and the scope of the appended claims should not be limited to the specific examples disclosed. In the following discussion, the terms "example" and "for example" are non-limiting.

[0017] The accompanying drawings illustrate the general construction method, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring this disclosure. Furthermore, the elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements in the figures may be enlarged relative to other elements to aid in understanding the examples discussed in this disclosure. The same reference numerals in different drawings denote the same elements.

[0018] The term "or" refers to any one or more items in a list connected by "or". As an example, "x or y" means any element in the three-element set {(x), (y), (x, y)}. As another example, "x, y or z" means any element in the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}.

[0019] The terms “comprises”, “comprising”, “includes”, and / or “including” are “open-ended” terms and specify the presence of the stated feature, but do not exclude the presence or addition of one or more other features.

[0020] The terms “first,” “second,” etc., may be used herein to describe various elements, and these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Thus, for example, without departing from the teachings of this disclosure, a first element discussed herein may be referred to as a second element.

[0021] Unless otherwise specified, the term "coupled" can be used to describe two elements that are in direct contact with each other or to describe two elements that are indirectly connected through one or more other elements. For example, if element A is coupled to element B, then element A can be in direct contact with element B or indirectly connected to element B through an intermediate element C. Similarly, the terms "above" or "on" can be used to describe two elements that are in direct contact with each other or to describe two elements that are indirectly connected through one or more other elements.

[0022] Embodiments of this disclosure may include a vertical-cavity surface-emitting exciter (VCSEL) device comprising a mesa with a non-circular cross-section. Embodiments may also include multiple layers comprising one or more oxide layers. Embodiments may also include one or more non-oxide layers. In some embodiments, the mesa may function as a dielectric top reflector.

[0023] In some embodiments, the oxide layer may include aluminum oxide (AlOx). In some embodiments, the non-oxide layer may include one or more of the following: aluminum gallium arsenide (AlGaAs), gallium arsenide (GaAs), aluminum indium phosphide (AlInP), gallium indium phosphide (GaInP), aluminum gallium arsenide phosphide (AlGaAsP), aluminum indium arsenide phosphide (AlInAsP), and / or gallium indium arsenide phosphide (GaInAsP). In some embodiments, one or more oxide layers and non-oxide layers may be arranged as an alternating stack of oxide layers and one or more non-oxide layers.

[0024] In some embodiments, the non-circular cross-section of the platform may be an elliptical cross-section. In some embodiments, the non-circular cross-section may include an elliptical planar shape or one or more concentric elliptical annular planes, or a plane formed by multiple adjacent circular planes. In some embodiments, the platform may include a passivation layer covering multiple layers.

[0025] In some embodiments, the passivation layer may include AlOx. In some embodiments, the mesa may include a stack of alternating AlGaAs or GaAs or AlInP or GaInP or AlGaAsP or AlInAsP or GaInAsP layers. In some embodiments, adjacent layers may include different aluminum contents.

[0026] Implementations may also include alternating layers forming a pair of mirrors. In some implementations, the mesa has a diameter of less than 6 micrometers. In some implementations, the non-circular cross-section can be operated to select one or more optical modes for emission. In some implementations, the non-circular cross-section can be operated for polarization mode splitting. Implementations may also include a top surface of the mesa, which may be planar, hemispherical, dome-shaped, or curvature-shaped. In some implementations, the device according to this disclosure may include one or more of a substrate, a bottom mirror, an active region, contacts, and a current-limiting structure such as an oxide aperture.

[0027] Traditional VCSELs lack sufficient bandwidth to achieve very high bandwidths, such as 200 Gbps operation. It may be desirable to provide smaller VCSELs with reduced capacity and higher parasitic bandwidth for faster operation. This disclosure describes a novel monolithic high-refractive-index contrast distributed Bragg reflector (DBR) for high-speed VCSELs.

[0028] In traditional VCSELs, current can be injected through top and bottom mirrors, which can be formed from a DBR (Distributed Bioreactor) comprising a semiconductor material such as aluminum gallium arsenide. In those DBRs, the refractive index contrast between the high and low refractive index materials can be small. This necessitates a large number of mirror pairs to achieve the desired high reflectivity. This presents disadvantages such as a higher mode volume, as well as resistive and absorptive mirrors.

[0029] This disclosure improves upon conventional VCSELs by using oxide layer stacking to form a mirror serving as the top DBR. The achieved refractive index difference can be higher, requiring fewer mirror pairs. The desired effects can be reduced mode volume and increased modulation bandwidth. Furthermore, the mirror can be non-absorbent, and the intracavity contact can be placed below the mirror to reduce resistance. The method of this invention can be monolithic and can be combined with other design options, such as lateral gratings and mode filters.

[0030] Now for reference Figure 1A , Figure 1A This is a block diagram illustrating a vertical-cavity surface-emitting laser device 100 according to some embodiments of the present disclosure. In some embodiments, the vertical-cavity surface-emitting laser device 100 may include a mesa 110. The mesa 110 may include a non-circular cross-section 112 and a plurality of layers 114. The plurality of layers 114 may include one or more oxide layers 116 and one or more non-oxide layers 118. The mesa 110 may operate as a dielectric top mirror. In some embodiments, the one or more non-oxide layers 118 may include AlOx.

[0031] In some embodiments, one or more of AlGaAs, GaAs, AlInP, GaInP, AlGaAsP, AlInAsP, and / or GaInAsP may be used for the non-oxide layer 118. In some embodiments, one or more oxide layers 116 and non-oxide layers 118 may be arranged as one or more stacks of alternating oxide layers and one or more non-oxide layers. In some embodiments, the non-circular cross-section 112 may be an elliptical cross-section. In some embodiments, the mesa 110 may have a diameter of less than 6 micrometers.

[0032] In some embodiments, the non-circular cross-section 112 can be operated to select one or more optical modes for emission. In some embodiments, the non-circular cross-section 112 can be operated for polarization mode splitting. In some embodiments, the top surface of the platform 110 can be planar, hemispherical, dome-shaped, or curved. In some embodiments, for example, as will be... Figure 1B As shown, it may include one or more of a substrate, a bottom mirror, an active region, a contact portion, and a current-limiting structure such as an oxide hole.

[0033] Figure 1B This is an exemplary embodiment of the present disclosure describing a vertical-cavity surface-emitting laser device 100. The vertical-cavity surface-emitting laser device 100 is shown, which may include a mesa 110. The mesa 110 may include a non-circular cross-section 112 (not shown) and a plurality of layers 114, the plurality of layers including one or more oxide layers 116 and one or more non-oxide layers 118. The mesa 110 can operate as a dielectric top reflector. A passivation layer 120 is also shown, covering the layers 116, 118. The passivation layer may be a protective layer. In some embodiments, the passivation layer 120 may include AlOx. A contact 122, an oxide via 124, an active region 126, a bottom reflector 127, and a substrate 128 are also shown.

[0034] In some embodiments, one or more oxide layers 116 may include AlOx. In some embodiments, one or more of AlGaAs, GaAs, AlInP, GaInP, AlGaAsP, AlInAsP, and / or GaInAsP may be used for the non-oxide layer 118. In some embodiments, one or more oxide layers 116 and non-oxide layers 118 may be arranged as an alternating stack of oxide layers and one or more non-oxide layers. In some embodiments, the mesa 110 may have a diameter of less than 6 micrometers.

[0035] Following the initial epitaxy of the vertical-cavity surface-emitting laser device 100, for example using AlGaAs layers with low and high aluminum content, oxidation can produce an AlOx-dominant layer 116 from the high-aluminum-content layer. Typically, the dielectric top mirror and oxide vias can be formed in the same process step. For example, the top DBR can be formed by fully oxidizing (approximately 98%) AlGaAs to create an AlOx / AlGaAs mirror. Epitaxial growth allows for precise definition of layer thickness. A suitable mirror with low absorption can result in lower optical losses, lower threshold current, and higher differential gain.

[0036] For example, etching can be used to form the mesa 110. In some embodiments, the non-circular cross-section 112 can be operated to select one or more optical modes for emission. In some embodiments, the non-circular cross-section 112 can be operated for polarization mode splitting. In some embodiments, the top surface of the mesa 110 can be planar, hemispherical, dome-shaped, or curved.

[0037] Reducing the size of the strong-mode diode can increase the bandwidth of the VCSEL 100. Small AlOx / AlGaAs DBRs can advantageously have small diameters, such as a few micrometers, for example less than 8 or 6 micrometers, to produce devices with low capacitance.

[0038] Figure 2A This further describes some embodiments according to this disclosure. Figure 1A A block diagram of a vertical-cavity surface-emitting laser device 100. In some embodiments, the non-circular cross-section 112 may be an elliptical cross-section. In some embodiments, the non-circular cross-section 112 may include an elliptical planar shape 212, one or more concentric elliptical annular planes 213, and a plane 214 formed by a plurality of adjacent circular planes.

[0039] Figure 2B An exemplary disclosure of a laser device 100 having an elliptical cross-section 112 is shown. An elliptical planar shape 212 is also shown.

[0040] Figure 2C An exemplary disclosure of a laser device 100 having a concentric elliptical annular cross section 112 / 213 is shown.

[0041] Figure 2D and Figure 2E Exemplary non-circular cross-sections 112 according to various embodiments of the present disclosure are shown. In some embodiments, the non-circular cross-section 112 may include one or more concentric elliptical annular planes 213. According to various embodiments of the present disclosure, Figure 2D A combination of elliptical planar shape 212 and elliptical annular shape 213 can be shown. Figure 2EAn exemplary non-circular cross section 112 may be shown, comprising a plane 214 formed by a plurality of adjacent circular planes 230, 232.

[0042] Figures 2B to 2E Some embodiments of the VCSEL 100 are shown, wherein the non-circular cross section 112 can be operated to select one or more optical modes for emission. In some embodiments, the non-circular cross section 112 can be operated for polarization mode splitting. According to various embodiments of this disclosure, a suitable selection of the non-circular cross section 112 can be advantageous for mode selection and splitting.

[0043] Figure 3A This further describes some embodiments according to this disclosure. Figure 1A A block diagram of a vertical-cavity surface-emitting laser device 100. In some embodiments, the mesa 110 may include a stack 315 of alternating AlGaAs or GaAs or AlInP or GaInP or AlGaAsP or AlInAsP or GaInAsP layers. The stack 315 may include different aluminum contents 316 in adjacent layers. In some embodiments, each pair of alternating layers may form a mirror pair.

[0044] Figure 3B This is an exemplary embodiment of the present disclosure comprising multiple mirror pairs. Hybrid mirror implementations are shown, including, for example, an AlOx / GaAs mirror pair 320 and an AlGaAs mirror pair 325. It should be understood that the specific materials used for the mirror pairs are exemplary.

[0045] Figure 3C This is an exemplary embodiment of the present disclosure that includes multiple pairs of reflectors. Figure 3C Similar to Figure 3B However, the exemplary AlOx / GaAs mirror pair 320 and AlGaAs mirror pair 325 are stacked in a different order. It should be understood that the specific materials used for the mirror pairs are exemplary.

[0046] This disclosure includes references to specific examples; however, those skilled in the art will understand that various changes can be made and equivalent features can be substituted without departing from the scope of this disclosure. Furthermore, modifications can be made to the disclosed examples without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the disclosed examples, but rather to include all examples falling within the scope of the appended claims.

Claims

1. A vertical-cavity surface-emitting laser device, the vertical-cavity surface-emitting laser device comprising: The countertop, the countertop comprising: Non-circular cross-section; and Multiple layers, the multiple layers including: One or more oxide layers; and One or more non-oxide layers; The platform is operable as a dielectric top reflector and provides mode selection.

2. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The oxide layer comprises AlOx.

3. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The non-oxide layer includes one or more of AlGaAs, GaAs, AlInP, GaInP, AsGaAsP, AlInAsP, and / or GaInAsP.

4. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The one or more oxide layers and the non-oxide layers are arranged in an alternating stack of oxide layers and one or more non-oxide layers.

5. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The non-circular cross section is an elliptical cross section.

6. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The non-circular cross-section includes an elliptical plane shape and / or one or more concentric elliptical annular planes, and / or a plane formed by multiple adjacent circular planes.

7. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The platform is covered with a passivation layer.

8. The vertical-cavity surface-emitting laser device according to claim 7, wherein, The passivation layer comprises AlOx.

9. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The mesa comprises a stack of alternating AlGaAs or GaAs or AlInP or GaInP or AsGaAsP or AlInAsP or GaInAsP layers, wherein adjacent layers comprise different aluminum contents.

10. The vertical-cavity surface-emitting laser device according to claim 9, wherein, Each pair in the alternating layers forms a mirror pair.

11. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The platform has a diameter of less than 6 micrometers.

12. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The non-circular cross section can be operated to select one or more optical modes for emission.

13. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The non-circular cross section can be operated for polarization mode splitting.

14. The vertical-cavity surface-emitting laser device according to claim 1, wherein, The top surface of the platform is flat, hemispherical, dome-shaped, or curved.

15. The vertical cavity surface-emitting laser device according to claim 1, further comprising one or more of a substrate, a bottom mirror, an active region, a contact portion, and a current limiting structure.

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