Vertical cavity surface emitting laser providing polarization mode control

Abstract

Embodiments of the present disclosure relate to a vertical cavity surface emitting laser providing polarization mode control. In some implementations, a vertical cavity surface emitting laser (VCSEL) includes a confinement layer and a polarization mode filter. The confinement layer defines a confinement aperture. The confining aperture is asymmetric with respect to at least one axis of the confining aperture. The polarization mode filter includes a grating. The limiting aperture and polarization mode filter are configured to control the number of optical modes supported by the VCSEL and lock polarization of each optical mode supported by the VCSEL.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Patent Application No. 63 / 602,926, filed on November 27, 2023, entitled “VERTICAL CAVITY SURFACE EMISSION LASER WITH INTEGRATED GRATING FOR POLARIZATION MODE CONTROL.” The disclosure of the prior application is considered a part of and incorporated by reference into this patent application. Technical Field

[0003] The present disclosure relates generally to vertical-cavity surface-emitting lasers (VCSELs) and to VCSELs providing polarization mode control. Background Art

[0004] The emitter may include a vertical emitting device, such as a VCSEL. A VCSEL is a laser that emits a laser beam in a direction perpendicular to (eg, perpendicularly from) the surface of the VCSEL. Multiple emitters may be arranged in an emitter array with a common substrate. Summary of the invention

[0005] In some implementations, the VCSEL includes a confinement layer; and a polarization mode filter, wherein: the confinement layer defines a confinement aperture, the confinement aperture is asymmetric with respect to at least one axis of the confinement aperture, and the polarization mode filter includes a grating, and the confinement aperture and the polarization mode filter are configured to control the number of optical modes supported by the VCSEL and lock the polarization of each optical mode supported by the VCSEL.

[0006] In some implementations, an optical component includes one or more VCSELs, wherein each VCSEL includes: a confinement layer; and a polarization mode filter, wherein: the confinement layer defines a confinement aperture, and the confinement aperture and the polarization mode filter are configured to control the number of optical modes supported by the VCSEL and lock the polarization of each optical mode supported by the VCSEL.

[0007] In some implementations, a wafer includes a plurality of VCSELs, wherein each VCSEL includes: a confinement layer defining a confinement aperture; and a polarization mode filter, wherein: the confinement aperture and the polarization mode filter are configured to control the number of optical modes supported by the VCSEL and to lock the polarization of each optical mode supported by the VCSEL. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a diagram associated with an example VCSEL.

[0009] Figure 2A-2B are diagrams depicting top views of different configurations of example VCSELs.

[0010] Figure 3A-3B is an example diagram related to a polarization mode filter of an example VCSEL.

[0011] Figure 4 are diagrams associated with example optical devices.

[0012] Figure 5 is a diagram associated with an example wafer. DETAILED DESCRIPTION

[0013] The following detailed description of example implementations refers to the accompanying drawings.The same reference numbers in different drawings may identify the same or similar elements.

[0014] The VCSEL includes a laser cavity that may include a cylindrical waveguide defined by an aperture to confine propagating optical energy. A top reflector and a bottom reflector are typically deposited or grown on both sides of the cylindrical waveguide (e.g., the top and bottom of the cylindrical waveguide) to form the laser cavity. It is noteworthy that the cylindrical waveguide can support a variety of optical modes (also referred to as resonant optical modes) with different propagation speeds, spatial distributions, and polarizations. Controlling or reducing the number of optical modes within the VCSEL is based at least in part on the geometry of the cylindrical waveguide (e.g., aperture size, shape, and / or other dimensions) and the reflective properties of the top reflector and the bottom reflector.

[0015] In many cases, the aperture of a VCSEL (e.g., including a cylindrical waveguide) defines a symmetry of propagation of optical modes (e.g., within a cylindrical waveguide). The light energy distribution then follows the symmetry in space. In some cases, optical modes with the same symmetry have identical (or nearly identical) propagation velocities (i.e., degenerate), and different linear combinations of those optical modes can have different polarizations that coexist in the laser cavity of the VCSEL (e.g., within a cylindrical waveguide). When the cylindrical waveguide of the VCSEL supports degenerate optical modes and the degenerate optical modes follow propagation symmetry, optical modes with different polarizations appear inside the laser cavity. The linear combination of optical modes (e.g., the linear combination ratio) typically varies with the drive current, and thus the polarization determined by the linear combination ratio changes (e.g., randomly or unpredictably) with the range of operating currents. Polarization cannot be locked by adjusting the aperture geometry alone.

[0016] In some cases, excessive beat noise may occur when optical modes interact within a VCSEL (e.g., within the laser cavity of the VCSEL). Other effects, such as spatial hole burning and sudden divergence angles, that occur due to changes in the operating current of the VCSEL may also cause problems when the optical modes do not have locked polarization (e.g., unchanged polarization). Therefore, minimizing these types of interactions and effects is very important for improving the optical signal quality of the laser beam emitted by the VCSEL, such as to facilitate optical communications and / or optical sensing.

[0017] Some implementations described herein include a VCSEL having a confinement layer and a polarization mode filter. The confinement layer defines a confinement aperture, and the confinement aperture and the polarization mode filter are configured to control the number of optical modes supported by the VCSEL and lock the polarization of each optical mode supported by the VCSEL.

[0018] For example, the limiting aperture can be asymmetric with respect to at least one axis of the limiting aperture, which can reduce the number of optical modes supported by the VCSEL (e.g., by achieving enhancement of one optical mode and reduction and / or elimination of one or more other optical modes). In addition, the polarization mode filter can suppress one of two orthogonal polarization orientations of light so that each optical mode supported by the VCSEL has a single polarization orientation. For example, the polarization mode filter can include a grating that allows reflection of light associated with one polarization orientation (e.g., aligned with a grating axis of the grating) and blocks light associated with an orthogonal polarization orientation. This allows each optical mode supported by the VCSEL to have a locked polarization (e.g., along a grating axis of the grating of the polarization mode filter).

[0019] In this manner, some implementations described herein include VCSELs that provide polarization mode control. By controlling the number of optical modes supported by the VCSEL and by locking the polarization of each optical mode supported by the VCSEL, the likelihood of excessive beat noise that may occur based on the interaction of optical modes within the VCSEL can be reduced and / or eliminated (e.g., due to a reduction in the number of optical modes that each have a locked polarization). In addition, other effects, such as spatial hole burning and sudden divergence angles, are less likely to occur because the optical modes have locked polarizations. Therefore, the VCSEL emits a laser beam with improved optical signal quality (e.g., compared to a laser beam emitted by a VCSEL without a confinement layer and a polarization mode filter, as described herein), which can facilitate improvements in optical communication applications, optical sensing applications, or any other optical application requiring improved optical signal quality.

[0020] Figure 1is a diagram associated with an example VCSEL 100. In some implementations, the VCSEL 100 can be included in an array of emitters (e.g., an array of VCSELs 100). In some implementations, such as Figure 1 As shown, VCSEL 100 is a top-emitting emitter. Alternatively, in some implementations, VCSEL 100 may be a bottom-emitting emitter (e.g., having Figure 1 , but modified to enable bottom emission). Figure 1 As shown, VCSEL 100 may include substrate 102, bottom metal 104, bottom mirror structure 106, a cavity including one or more active regions (referred to herein as cavity region 108), confinement layer 110 forming confinement aperture 112, top mirror structure 114, top contact layer 116, dielectric layer 118, top metal 120, one or more isolation implants 122, and / or polarization mode filter 124. As shown, one or more layers of VCSEL 100 (e.g., top contact layer 116, dielectric layer 118, top metal 120, polarization mode filter 124, etc.) may form output aperture 126.

[0021] The substrate 102 includes a support material on which one or more layers or features of the VCSEL 100 are grown or fabricated, or within which one or more layers or features of the VCSEL 100 are grown or fabricated. In some implementations, the substrate 102 includes an n-type material. In some implementations, the substrate 102 includes a semi-insulating material. In some implementations, when the VCSEL 100 includes one or more bottom-emitting emitters, a semi-insulating material may be used to reduce optical absorption from the substrate 102. In such an implementation, the VCSEL 100 may include a contact buffer in or near the bottom reflector structure 106. In some implementations, the substrate 102 may be formed of a semiconductor material, such as gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), indium phosphide (InP), or another type of semiconductor material. In some implementations, the bottom contact (e.g., bottom n-contact) of the VCSEL 100 may be made from the back side of the substrate 102. In some implementations, the bottom contact of the VCSEL 100 may be made from the front side of the VCSEL 100. In some implementations, the front contact may be implemented by, for example, etching mesa steps or trenches on the substrate 102 , or inserting a contact buffer in or near the bottom mirror structure 106 .

[0022] The bottom metal 104 includes a metal layer on the bottom surface of the substrate 102 (e.g., at the back side of the VCSEL 100). In some implementations, the bottom metal 104 is formed of an n-type material. In some implementations, the bottom metal 104 is a layer that is in electrical contact with the substrate 102. In some implementations, the bottom metal 104 serves as a cathode for the VCSEL 100. In some implementations, the bottom metal 104 can include an annealed metallization layer, such as a gold germanium nickel (AuGeNi) layer, a palladium germanium gold (PdGeAu) layer, and the like.

[0023] The bottom reflector structure 106 is a bottom reflector of an optical resonator of the VCSEL 100. For example, the bottom reflector structure 106 may include a distributed Bragg reflector (DBR), a dielectric reflector, or another type of reflector structure. In some implementations, the bottom reflector structure 106 is formed of an n-type material. In some implementations, the bottom reflector structure 106 is on the top surface of the substrate 102. In some implementations, the thickness of the bottom reflector structure 106 may be in a range of about 3.5 micrometers (μm) to about 9 μm (e.g., greater than or equal to 3.5 μm and less than or equal to 9 μm), such as 5 μm. In some implementations, the bottom reflector structure 106 includes a set of layers (e.g., aluminum gallium arsenide (AlGaAs) layers) grown using a metal organic chemical vapor deposition (MOCVD) technique, a molecular beam epitaxy (MBE) technique, or another technique.

[0024] The cavity region 108 includes one or more layers where electrons and holes recombine to emit light and define the emission wavelength range of the VCSEL 100. For example, the cavity region 108 may include one or more active regions in the form of one or more quantum wells (QWs). In some implementations, the cavity region 108 may include one or more cavity spacer layers (e.g., to allow epitaxial growth to have sufficient space for increasing composition or temperature). In some implementations, the one or more cavity spacer layers may reduce strain between active regions of the cavity region 108 and / or may alleviate thermal issues of laser operation of the VCSEL 100. In some implementations, the one or more cavity spacer layers may include an oxide layer. The optical thickness of the cavity region 108 (including one or more active regions and any cavity spacer layers), the top reflector structure 114, and the bottom reflector structure 106 define the resonant cavity wavelength of the VCSEL 100, which may be designed to be within the emission wavelength range of the cavity region 108 to enable laser emission. In some implementations, the cavity region 108 may be formed on the bottom reflector structure 106. In some implementations, the thickness of the cavity region 108 can be in a range of about 0.006 μm to about 0.5 μm, such as 0.15 μm or 0.30 μm. In some implementations, the cavity region 108 includes a set of layers grown using a MOCVD technique, an MBE technique, or another technique.

[0025] The confinement layer 110 is a layer that provides optical confinement and / or electrical confinement for the VCSEL 100. In some implementations, the confinement layer 110 enhances carrier and optical mode confinement of the VCSEL 100, and thus can improve the performance of the VCSEL 100. In some implementations, the confinement layer 110 is on, below, or in the cavity region 108. In some implementations, there can be one or more spacer layers or reflector layers (e.g., DBR) between the confinement layer 110 and the cavity region 108. In some implementations, the confinement layer 110 is on a side of the cavity region 108 that is closer to the bottom reflector structure 106 (i.e., on the substrate side of the cavity region 108) (e.g., the confinement layer 110 can be below the cavity region 108). In some implementations, the confinement layer 110 is on a side of the cavity region 108 that is closer to the top mirror structure 114 (ie, on a non-substrate side of the cavity region 108 ) (eg, the confinement layer 110 may be above the cavity region 108 ).

[0026] In some implementations, the confinement layer 110 is an oxide layer formed by oxidation of one or more epitaxial layers of the VCSEL 100. For example, the confinement layer 110 may be an aluminum oxide (AlO) layer formed by oxidation of an epitaxial layer (e.g., an AlGaAs layer, an AlAs layer, etc.). 2 O 3) layer. In some implementations, the thickness of the confinement layer 110 can be in the range of about 0.007 μm to about 0.04 μm, such as 0.02 μm. In some implementations, the oxide trench etched around the VCSEL 100 (in Figure 1 100) may allow steam to enter the epitaxial layer(s) from which the confinement layer 110 is formed. In some implementations, the oxidation trenches may not completely surround the confinement layer 110. For example, the oxidation trenches may follow the general shape of the confinement region, but there may be gaps between adjacent oxidation trenches. In some implementations, the confinement layer 110 may follow a general geometry, but may have variations associated with the shape or position of the oxidation trenches and / or variations associated with the oxidation rate. In some implementations, in addition to the confinement layer 110, the VCSEL 100 may also include one or more other types of structures or layers that provide current confinement, such as an implanted passivation structure, a mesa isolation structure, a moat trench isolation structure, a buried tunnel junction, etc. In addition, or alternatively, such other types of structures or layers for providing current confinement may be included in the confinement layer 110 or integrated with the confinement layer 110.

[0027] In some implementations, the confinement layer 110 defines a confinement pore 112. Thus, in some implementations, the confinement pore 112 is an optically active pore defined by the confinement layer 110. In some implementations, the size of the confinement pore 112 (e.g., the width in a given direction) is in the range of about 1 μm to about 300 μm, such as 5 μm or 8 μm. In some implementations, the confinement pore 112 can be formed by oxidation (e.g., when the confinement layer 110 is an oxidized layer). Additionally, or alternatively, the confinement pore 112 can be formed by other means, such as by implantation, diffusion, regrowth (e.g., using a high resistance layer, a current blocking layer, a tunnel junction, etc.), or an air gap, etc.

[0028] The limiting aperture 112 may have a particular shape (e.g., when viewed from the top of the VCSEL 100), such as a circular shape, an elliptical shape, a polygonal shape, etc. In some implementations, the limiting aperture 112 is asymmetric with respect to at least one axis associated with the limiting aperture 112 (e.g., the limiting aperture 112 may not be rotationally symmetric). For example, the limiting aperture 112 may have an elliptical shape (e.g., the limiting aperture is symmetric about the long axis and the short axis of the limiting aperture 112, but not about another axis of the limiting aperture 112), or a rectangular shape (e.g., the limiting aperture is symmetric about the length axis and the width axis of the limiting aperture 112, but not about another axis of the limiting aperture 112), a teardrop shape (e.g., the limiting aperture is symmetric about the length axis of the limiting aperture 112, but not about another axis of the limiting aperture 112), among other examples. In this manner, the confining aperture 112 may be configured to reduce the number of optical modes supported by the confining aperture 112 (and therefore supported by the VCSEL 100), such as due to a particular shape of the confining aperture 112 and a size of the confining aperture 112. For example, when the confining aperture 112 is asymmetric, one optical mode (e.g., a fundamental optical mode) may be enhanced, and one or more other optical modes may be reduced and / or eliminated.

[0029] Thus, the limiting aperture 112 (e.g., due to a specific shape of the limiting aperture 112 and / or a size of the limiting aperture 112) can be configured to support a single optical mode. This may result in the VCSEL 100 being a single-mode (SM) VCSEL (e.g., the single-mode VCSEL emits a laser beam having only one optical mode (such as a fundamental optical mode)). Alternatively, the limiting aperture 112 (e.g., due to a specific shape of the limiting aperture 112 and / or a size of the limiting aperture 112) can be configured to support one or more optical modes (e.g., by allowing laser emission of one or more optical modes and / or by suppressing laser emission of one or more other optical modes). This may result in the VCSEL 100 being a reduced-mode (RM) VCSEL (e.g., the reduced-mode VCSEL emits a laser beam having a reduced number of optical modes (such as a fundamental optical mode and one or more higher-order optical modes)).

[0030] The top reflector structure 114 is a top reflector of the optical resonator of the VCSEL 100. For example, the top reflector structure 114 may include a DBR, a dielectric reflector, etc. In some implementations, the top reflector structure 114 is formed of a p-type material. In some implementations, the thickness of the top reflector structure 114 may be in the range of about 1 μm to about 6 μm, such as 3 μm. In some implementations, the top reflector structure 114 includes a set of layers (e.g., AlGaAs layers) grown using MOCVD technology, MBE technology, or another technology. In some implementations, the top reflector structure 114 is grown on or above the cavity region 108.

[0031] In some implementations, the total thickness from the bottom surface of the bottom reflector structure 106 to the top surface of the top reflector structure 114 can be, for example, in the range of about 4.5 μm to about 26.4 μm, such as about 8.6 μm. In some implementations, the thickness of one or more of the layers of the VCSEL 100 can be selected to provide a structure that achieves high reflectivity (e.g., a reflectivity greater than about 99%). In some implementations, a smaller total thickness can facilitate a reduced growth time of the VCSEL 100 or reduced stress within the VCSEL 100.

[0032] The top contact layer 116 is in electrical contact with the top reflector structure 114, and current can flow through the top reflector structure. In some implementations, the top contact layer 116 includes an annealed metallization layer. For example, the top contact layer 116 may include a chromium-gold (Cr-Au) layer, a gold-zinc (Au-Zn), a titanium-platinum-gold (TiPtAu) layer, a gold-germanium-nickel (AuGeNi) layer, a palladium-germanium-gold (PdGeAu) layer, etc. In some implementations, the thickness of the top contact layer 116 is in the range of about 0.03 μm to about 0.3 μm, such as 0.2 μm. In some implementations, the top contact layer 116 has a ring shape, a slotted ring shape, a gear shape, or another type of circular or non-circular shape (e.g., depending on the design of the VCSEL 100).

[0033] The dielectric layer 118 is a layer that at least partially insulates the top metal 120 from one or more other layers or features (e.g., the sidewalls of the trench). In some implementations, the dielectric layer 118 may include, for example, silicon nitride (SiN), silicon dioxide (SiO 2 ), polymer dielectric, or another type of insulating material.

[0034] The top metal 120 is a top metal layer at the front side of the VCSEL 100. In some implementations, the top metal 120 is formed of a p-type material. Alternatively, in some implementations, the top metal 120 is formed of an n-type material. In some implementations, the top metal 120 can be a layer that is in electrical contact with the top contact layer 116. In some implementations, the top metal 120 can be used as an anode for the VCSEL 100.

[0035] Isolation implants 122 are regions that prevent free carriers from reaching the edges of the trenches and / or isolate adjacent VCSELs 100 from each other (e.g., when the trenches do not completely surround VCSELs 100). Isolation implants 122 may include, for example, ion implant materials such as hydrogen / proton implant materials or similar implant elements to reduce conductivity.

[0036] The polarization mode filter 124 can be associated with the polarization of the light (e.g., laser beam) emitted by the VCSEL 100. For example, the polarization mode filter 124 can introduce a polarization dependence on the reflectivity and / or transmittance of the VCSEL 100, which has the effect of suppressing one of two orthogonal polarization orientations of the light (e.g., causing the light emitted by the VCSEL 100 to have a single polarization orientation). Additionally, or alternatively, the polarization mode filter 124 can be associated with an increase in reflectivity on a side of the VCSEL 100 that includes the top reflector structure 114.

[0037] The polarization mode filter 124 can be configured to lock the polarization of each of the one or more optical modes (e.g., of a laser beam) supported by the limiting aperture 112 (and therefore supported by the VCSEL 100). For example, when the limiting aperture 112 supports a single optical mode (e.g., when the VCSEL 100 is an SM VCSEL), the polarization mode filter 124 can cause the single optical mode to have a specific polarization and not have any other polarizations (e.g., by selecting a specific polarization of the single optical mode, and / or filtering another polarization, or preventing the selection of another polarization). As another example, when the limiting aperture 112 supports one or more optical modes (e.g., when the VCSEL 100 is an RM VCSEL), the polarization mode filter 124 can cause each of the one or more optical modes to have the same polarization and not have any other polarizations (e.g., by selecting the same polarization for the one or more optical modes, and / or filtering one or more other polarizations, or preventing the selection of one or more other polarizations).

[0038] In some implementations, the polarization mode filter 124 is on, below, or in at least one of the top reflector structure 114, the dielectric layer 118, or any other layer or structure above the limiting aperture 112. In some implementations, the polarization mode filter 124 can include a grating that can have a grating depth and a grating period that are on the order of magnitude of or lower than the wavelength of the VCSEL 100. In some implementations, the polarization mode filter 124 includes an AlGaAs layer. In some implementations, the thickness of the polarization mode filter 124 can be in a range of about 0.06λ to about 0.26λ, where λ is the wavelength of the VCSEL 100. In one example, for a 940 nm wavelength (λ=940 nm), the thickness of the polarization mode filter 124 can be in a range of about 50 nm to about 250 nm.

[0039] In some implementations, when the polarization mode filter 124 includes a grating, the polarization mode filter can be oriented to a specific axis of the limiting aperture 112, such as a symmetry axis of the limiting aperture 112. That is, a grating axis of the grating of the polarization mode filter 124 (e.g., the direction in which the grooves of the grating extend) can be aligned (e.g., parallel) to the specific axis of the limiting aperture 112 (e.g., within a tolerance range, such as 1, 2, or 3 degrees), or can be set to a specific angle (e.g., a non-zero angle) to the specific axis of the limiting aperture 112 (e.g., within a tolerance range), such as 30 degrees, 45 degrees, 60 degrees, 75 degrees, or other angles. For example, when the limiting aperture 112 has an elliptical shape, the grating axis of the grating of the polarization mode filter 124 can be aligned with the long axis of the limiting aperture 112. As another example, when the limiting aperture 112 has a rectangular shape, the grating axis of the grating of the polarization mode filter 124 can be set to a specific angle (e.g., 20 degrees) to the long axis of the limiting aperture 112.

[0040] Output aperture 126 is an aperture of VCSEL 100 through which light (e.g., a laser beam) is emitted. As shown, output aperture 126 may be defined by one or more layers of VCSEL 100, such as top contact layer 116, dielectric layer 118, top metal 120, or polarization mode filter 124. In some implementations, the size of output aperture 126 (e.g., the width in a given direction) is in the range of about 1 μm to about 300 μm, such as 5 μm or 8 μm.

[0041] Figure 1 The number, arrangement, thickness, order, symmetry, etc. of the layers shown are provided as examples only. Figure 1VCSEL 100 may include additional layers, fewer layers, different layers, differently constructed layers, or differently arranged layers than those shown. For example, as described above, VCSEL 100 may be a bottom emitting VCSEL in some implementations and may utilize a substrate similar to Figure 1 The structure shown is for bottom emission, with appropriate modifications to support bottom emission (e.g., the output aperture may be formed at the bottom of the VCSEL rather than the top). Additionally, or alternatively, a set of layers (e.g., one or more layers) of VCSEL 100 may perform one or more functions described as being performed by another set of layers of VCSEL 100, and any layer may include more than one layer. While some implementations described herein involve a single VCSEL (e.g., VCSEL 100), some implementations include multiple VCSELs (e.g., multiple VCSELs 100).

[0042] Figure 2A-2B 2 is a diagram 200 depicting a top view of different configurations of an example VCSEL 100. Figure 2A-2B As shown, the output aperture 126 may be surrounded (eg, completely or partially) by the top metal 120. Figure 2A-2B As further shown, the polarization mode filter 124 can be disposed above the limiting aperture 112 (e.g., as described above with respect to Figure 1 ), the limiting aperture is shown as having an elliptical shape having a major axis 202 (eg, the major axis is the axis of symmetry of the limiting aperture 112).

[0043] Figure 2A A polarization mode filter 124 is shown that includes a grating having a grating axis 204-A that is aligned with the long axis 202 of the limiting aperture 112 (e.g., the grating axis 204-A is parallel to the long axis 202). In this manner, the grating of the polarization mode filter 124 is configured to reflect an optical mode (e.g., of a laser beam emitted by the VCSEL 100) whose polarization is along the grating axis 204-A (and thus along the long axis 202 of the limiting aperture 112). In addition, the grating of the polarization mode filter 124 is configured to filter (or prevent reflection) of another optical mode (e.g., of a laser beam emitted by the VCSEL 100) whose polarization is not along the grating axis 204-a (and thus not along the long axis 202 of the limiting aperture 112), which therefore suppresses the other optical mode (e.g., by preventing resonance required for lasing of the other optical mode). Thus, the grating of the polarization mode filter 124 locks the polarization of any optical mode supported by the limiting aperture 112 along the grating axis 204 -A (and thus along the long axis 202 of the limiting aperture 112 ).

[0044] Figure 2B A polarization mode filter 124 is shown that includes a grating having a grating axis 204-B that is disposed at an orthogonal angle (e.g., 90 degrees) to the long axis 202 of the limiting aperture 112 (e.g., the grating axis 204-B is orthogonal to the long axis 202). In this manner, the grating of the polarization mode filter 124 is configured to reflect an optical mode (e.g., of a laser beam emitted by the VCSEL 100) whose polarization is along the grating axis 204-B (and thus is orthogonal to the long axis 202 of the limiting aperture 112). In addition, the grating of the polarization mode filter 124 is configured to filter (or prevent reflection) of another optical mode (e.g., of a laser beam emitted by the VCSEL 100) whose polarization is not along the grating axis 204-B (and thus is not orthogonal to the long axis 202 of the limiting aperture 112), thereby suppressing the other optical mode (e.g., by preventing resonance required for lasing of the other optical mode). Thus, the grating of polarization mode filter 124 locks the polarization of any mode supported by limiting aperture 112 to be along grating axis 204 -B (and therefore orthogonal to long axis 202 of limiting aperture 112 ).

[0045] As indicated above, Figure 2A-2B Provided as an example. Other examples may differ from Figure 2A-2B An example of description.

[0046] Figure 3A-3B is an example diagram 300 associated with the polarization mode filter 124 of the VCSEL 100 . Figure 3A An example configuration of a polarization mode filter 124 is shown that includes a grating having a grating axis aligned with (eg, parallel to) the y-axis (also in FIG. Figure 3A Therefore, if Figure 3A As further shown, the grating may include a plurality of grooves placed along the polarization mode filter 124 in a direction aligned with the x-axis (eg, according to the grating period). Figure 3A As further shown, Rx is the reflectivity of the grating of the polarization mode filter 124 for light (e.g., the optical mode of a laser beam) polarized in a direction aligned with the x-axis (e.g., the main electric field), and Ry is the reflectivity of the grating of the polarization mode filter 124 for light polarized in a direction aligned with the y-axis.

[0047] like Figure 3BAs shown, Rx can be greater than Ry, such as for a wavelength 302 associated with a fundamental optical mode of the VCSEL 100. Thus, the grating of the polarization mode filter 124 can support resonance of light in a direction aligned with the x-axis and can suppress resonance of light in a direction aligned with the y-axis. In this manner, the grating of the polarization mode filter 124 can lock the polarization of any optical mode supported by the confining aperture 112 of the VCSEL 100 in a direction aligned with the x-axis (e.g., along the grating axis of the polarization mode filter 124).

[0048] As indicated above, Figure 3A-3B Provided as an example. Other examples may differ from Figure 3A-3B Examples described.

[0049] Figure 4 3 is a diagram associated with an example optical device 400. The example optical device 400 may be, for example, an optical communication device, an optical sensing device, an optical interconnect device, an optical structured light device, or another type of optical device. The optical device 400 may include an optical component 402, which may include one or more VCSELs 100 (shown as three VCSELs 100 in FIG. 3 ), which may be arranged in a pattern (e.g., a one-dimensional array, a two-dimensional array, or another type of pattern) within the optical component 402.

[0050] One or more VCSELs 100 can be configured to emit a corresponding laser beam, such as a corresponding laser beam to be coupled to (e.g., into) an input end of an optical fiber (e.g., a single-mode optical fiber or a multi-mode optical fiber). The corresponding laser beams can be associated with the same spectral range. That is, each VCSEL 100 can be configured to emit a laser beam associated with a specific spectral range. For example, each VCSEL 100 can be configured to emit a laser beam associated with a spectral range having a central wavelength of 850 nm.

[0051] Furthermore, each VCSEL 100 can be configured to emit a laser beam having one or more optical modes, each of which is locked to a specific polarization. Figure 4As shown, each VCSEL 100 may include a limiting aperture 112 that supports one or more optical modes (e.g., to make each VCSEL 100 an SM VCSEL or an RM VCSEL) and a polarization mode filter 124 that causes each of the one or more optical modes to have the same polarization (e.g., along a grating axis 204 of a grating of the polarization mode filter 124). Notably, the corresponding grating axes 204 of the one or more VCSELs 100 may be aligned with each other (e.g., parallel to each other within a tolerance range), which causes the one or more optical modes of each laser beam emitted by the one or more VCSELs to have the same polarization. This may facilitate coupling of the laser beam into an optical fiber (e.g., by ensuring that the polarization of the laser beam is aligned with the polarization axis of the optical fiber).

[0052] As indicated above, Figure 4 Provided as an example. Other examples may differ from Figure 4 Examples described.

[0053] Figure 5 is a diagram associated with an example wafer 500. Wafer 500 may be used to produce integrated circuits, chips, semiconductor lasers, etc. For example, wafer 500 may be used to form a plurality of VCSELs 100 (e.g., where a plurality of VCSELs 100 are formed on a uniform substrate and then the use of the VCSELs 100 may be tailored to individual needs using a singulation process).

[0054] like Figure 5 As shown, a plurality of VCSELs 100 may be formed on a surface (e.g., a top surface) of a wafer 500. As described elsewhere herein, each VCSEL 100 may be configured to support one or more optical modes (e.g., due to a confining aperture 112 of the VCSEL 100), wherein each optical mode has a polarization that is locked, such as in the same direction (e.g., due to a polarization mode filter 124 of the VCSEL 100). For example, Figure 5 As shown, each VCSEL 100 can be configured to emit a laser beam including one or more optical modes (e.g., due to the limiting aperture 112 of the VCSEL 100, the VCSEL 100 is a SMVCSEL or a RM VCSEL). Each optical mode can have the same polarization (e.g., along the grating axis 204 of the grating of the polarization mode filter 124 of the VCSEL 100). It is worth noting that, as Figure 5As shown, the respective grating axes 204 of the polarization mode filters 124 of a plurality of VCSELs 100 may be aligned with each other (eg, parallel to each other within a tolerance range), such that the VCSELs 100 are configured to emit respective laser beams each having one or more optical modes with the same polarization.

[0055] As indicated above, Figure 5 Provided as an example. Other examples may differ from Figure 5 Examples described.

[0056] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit implementation to the disclosed precise form. Modifications and changes may be made based on the above disclosure, or modifications and changes may be obtained from the practice of implementation. In addition, unless the foregoing disclosure explicitly provides a reason why one or more implementations may not be combined, any implementation described herein may be combined.

[0057] Even if a specific combination of features is described in the claims and / or a specific combination of features is disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. In fact, many of these features can be combined in a manner that is not specifically described in the claims and / or not specifically disclosed in the specification. Although each dependent claim listed below can only directly depend on one claim, the disclosure of various implementations includes each dependent claim combined with each other claim in the claim set. As used herein, the phrase "at least one" referring to a list of items refers to any combination of those items, including a single member. As an example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiples in the same item.

[0058] Unless clearly described as such, any element, action or instruction used in this article should not be interpreted as key or necessary. In addition, as used herein, the article "a (a)" and "an (an)" are intended to include one or more projects, and can be used interchangeably with "one or more". In addition, as used in the text, the article "the (the)" is intended to include one or more projects quoted in conjunction with the article "the", and can be used interchangeably with "the one or more". In addition, as used herein, the term "group" is intended to include one or more projects (for example, related projects, unrelated projects or related projects and unrelated projects The combination of projects), and can be used interchangeably with "one or more". In the case of only intending a project, the phrase "only one" or similar language is used. In addition, as used herein, the term "has (has)", "have (have)" and "having (having)" etc. are intended to be open terms. In addition, unless otherwise clearly stated, the phrase "based on" is intended to mean "at least partially based on". In addition, unless otherwise expressly stated (e.g., if used in combination with "either" or "only one of..."), as used herein, the term "or" when used in series is intended to be inclusive and may be used interchangeably with "and / or". In addition, for ease of description, spatially relative terms such as "below," "lower," "above," "upper," etc. may be used herein to describe the relationship of one element or feature to another element or feature, as shown in the accompanying drawings. Spatially relative terms are intended to cover different orientations of devices, equipment, and / or elements in use or in operation other than the orientation depicted in the accompanying drawings. The device may be oriented in other ways (rotated 90 degrees or oriented in other orientations), and the spatially relative descriptors used herein may also be interpreted accordingly.

Claims

1. A vertical cavity surface emitting laser (VCSEL), comprising: Restriction layer; as well as Polarization mode filter where: The confinement layer defines a confinement aperture, The confining aperture is asymmetric with respect to at least one axis of the confining aperture, and The polarization mode filter comprises a grating, and The confining aperture and the polarization mode filter are configured to control the number of optical modes supported by the VCSEL and to lock the polarization of each optical mode supported by the VCSEL.

2. The VCSEL according to claim 1, wherein: The confining aperture is configured to reduce the number of optical modes supported by the VCSEL.

3. The VCSEL according to claim 1, wherein: A grating axis of the grating of the polarization mode filter is aligned with an axis of symmetry of the limiting aperture.

4. The VCSEL according to claim 3, wherein: The polarization mode filter is configured to lock the polarization of each optical mode supported by the VCSEL along the grating axis of the grating of the polarization mode filter and the symmetry axis of the confining aperture.

5. The VCSEL according to claim 1, wherein: A grating axis of the grating of the polarization mode filter is arranged at a non-zero angle to the axis of symmetry of the confining aperture.

6. The VCSEL according to claim 5, wherein: The polarization mode filter is configured to lock the polarization of each optical mode supported by the VCSEL along the grating axis of the polarization mode filter and not along the symmetry axis of the confining aperture.

7. The VCSEL according to claim 1, wherein: The confinement layer is above a cavity region of the VCSEL, and the cavity region is above a substrate of the VCSEL; and The polarization mode filter is above the confining aperture.

8. An optical component comprising: One or more vertical cavity surface emitting lasers (VCSELs), wherein each VCSEL comprises: Restricted layers; and Polarization mode filter where: The confinement layer defines a confinement aperture, and The confining aperture and the polarization mode filter are configured to control the number of optical modes supported by the VCSEL and to lock the polarization of each optical mode supported by the VCSEL.

9. The optical assembly of claim 8, wherein: The restricting aperture is asymmetric with respect to at least one axis of the restricting aperture.

10. The optical assembly of claim 8, wherein: The polarization mode filter includes a grating.

11. The optical assembly of claim 8, wherein: The polarization mode filter is configured to lock the polarization of each optical mode supported by the VCSEL to a grating axis along a grating of the polarization mode filter.

12. The optical assembly of claim 11, wherein: The grating axis of the grating of the polarization mode filter is aligned with the symmetry axis of the limiting aperture.

13. The optical assembly of claim 11, wherein: The grating axis of the grating of the polarization mode filter is arranged at a non-zero angle to the symmetry axis of the limiting aperture.

14. The optical assembly of claim 11, wherein: The confinement layer is above a cavity region of the VCSEL, and the cavity region is above a substrate of the VCSEL; and The polarization mode filter is above the confining aperture.

15. A wafer comprising: A plurality of vertical cavity surface emitting lasers (VCSELs), wherein each VCSEL comprises: a confining layer defining a confining aperture; and Polarization mode filter where: The confining aperture and the polarization mode filter are configured to control the number of optical modes supported by the VCSEL and to lock the polarization of each optical mode supported by the VCSEL.

16. The wafer of claim 15, wherein: The restricting aperture is asymmetric with respect to at least one axis of the restricting aperture.

17. The wafer according to claim 15, wherein: The polarization mode filter includes a grating.

18. The wafer of claim 17, wherein: The polarization mode filter is configured to lock the polarization of each optical mode supported by the VCSEL to a grating axis along the grating of the polarization mode filter.

19. The wafer of claim 17, wherein: Grating axes of the gratings of the polarization mode filters of the plurality of VCSELs are aligned with each other.

20. The wafer of claim 15, wherein: The plurality of VCSELs are configured to emit respective laser beams each having one or more optical modes with the same polarization.

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