A laser chip and a method for manufacturing the same

Abstract

The laser chip and its fabrication method disclosed herein include a first reflective layer, an active region, an oxide layer, and a second reflective layer sequentially disposed on a substrate. The laser chip has a first trench and a second trench for oxidizing and etching the oxide layer. A first connecting portion connects one end of the first trench to one end of the second trench, and a second connecting portion connects the other end of the first trench to the other end of the second trench. Due to the influence of crystal anisotropy on the oxidation rate, and the mutual coordination of the first and second connecting portions on the oxidation rate, the oxide aperture includes a first oxide arc, a second oxide arc, a third oxide arc, and a fourth oxide arc. The first and second oxide arcs are arranged opposite each other, as are the third and fourth oxide arcs. The third and fourth oxide arcs have different radii of curvature, forming a specific irregular morphology. The oxide aperture based on the irregular morphology can effectively suppress transverse multimode lasing of the optical signal and reduce mode degeneracy.

Description

Technical Field

[0001] This disclosure relates to the field of optical communication technology, and in particular to a laser chip and its fabrication method. Background Technology

[0002] With the development of new business and application models such as cloud computing, mobile internet, and video, advancements in optical communication technology have become increasingly important. In optical communication technology, the optical module, as one of the key components in optical communication equipment, enables photoelectric signal conversion; and in the development of optical communication technology, the data transmission rate of optical modules is required to continuously improve.

[0003] The optical module includes an optical emitting component, which in turn includes a laser chip. This laser chip can be a Vertical Cavity Surface Emitting Laser (VCSEL). In a VCSEL, the laser emission direction is perpendicular to the resonant cavity surface. High-speed VCSELs cannot achieve transverse single-mode lasing, thus reducing optical power and modulation rate. Summary of the Invention

[0004] Some embodiments provide a laser chip and a method for fabricating the same, which suppresses lateral multimode lasing of the laser chip by forming oxide holes with specific morphology.

[0005] In some embodiments, a laser chip is provided, comprising:

[0006] The substrate has a surface crystal plane index at a predetermined angle to the crystal plane;

[0007] A first reflective layer is located above the substrate;

[0008] An active region, located above the first reflective layer, is configured such that N-type carriers and P-type carriers recombine in the active region to generate photons; the first reflective layer provides the N-type carriers to the active region;

[0009] An oxide layer is located above the active region. The oxide layer includes oxide holes, which are surrounded by a first oxide region. The oxide holes include a first oxidation arc, a second oxidation arc, a third oxidation arc, and a fourth oxidation arc. The first oxidation arc and the second oxidation arc are arranged opposite to each other, and the third oxidation arc and the fourth oxidation arc are arranged opposite to each other. The radii of curvature of the third oxidation arc and the fourth oxidation arc are different.

[0010] The second reflective layer, located above the oxide layer, is configured to provide P-type charge carriers to the active region, which flow into the active region along the oxide aperture; the second reflective layer and the first reflective layer form a resonant cavity, in which photons oscillate to generate laser light, and a corresponding modulated optical signal is generated by modulating an electrical signal, which is output from the oxide aperture in a direction perpendicular to the substrate surface.

[0011] The first trench extends downward along the surface of the second reflective layer to above the active region, and the first trench is located on one side of the first oxide region;

[0012] The second trench extends downward along the surface of the second reflective layer to above the active region, and the second trench is located on the other side of the first oxide region; a first connecting portion is connected between one end of the second trench and one end of the first trench, and a second connecting portion is connected between the other end of the second trench and the other end of the first trench.

[0013] The above technical solution has the following advantages or beneficial effects: The laser chip includes a substrate. A first reflective layer, an active region, an oxide layer, and a second reflective layer are sequentially disposed on the substrate. The first reflective layer provides N-type carriers to the active region, and the second reflective layer provides P-type carriers to the active region. N-type carriers and P-type carriers recombine in the active region to generate photons. The second reflective layer and the first reflective layer form a resonant cavity, allowing photons to oscillate within the resonant cavity to generate laser light, and a corresponding modulated optical signal is generated by modulating an electrical signal. To oxidize and etch the oxide layer to form oxide holes for photoelectric confinement, etching is performed downwards along the surface of the second reflective layer to above the active region to form a first trench and a second trench, exposing the internal sidewalls of the oxide layer for oxidation and etching. The oxidized area of ​​the oxide layer forms a first oxide region, and the unoxidized area forms an oxide hole. The optical signal is output from the oxide hole in a direction perpendicular to the substrate surface. The oxide hole is surrounded by the first oxide region. The first oxide region is a low-refractive-index, insulating oxide region, while the oxide hole is a high-refractive-index, high-conductivity, unoxidized region. Consequently, the light field is output along the oxide hole, and charge carriers are transported to the active region along the oxide hole, exhibiting good photoelectric confinement performance. The oxide hole confines the light and electric fields vertically, reducing lateral diffusion of the light field and charge carriers. To form oxide holes of a specific morphology, a first connecting portion connects one end of the first trench to one end of the second trench, and a second connecting portion connects the other end of the first trench to the other end of the second trench. The first and second connecting portions can serve as control variables for the formation of the specific morphology of the oxide hole. During the formation of the oxide hole with a specific morphology, since the crystal plane index of the substrate surface is at a preset angle to its crystal plane, the crystal plane index of the oxide layer surface also forms a preset angle with its crystal plane, resulting in anisotropy of the oxide layer's crystal orientation. Due to anisotropy, the atomic composition, spatial structure, and interlayer distances differ across crystal orientations, resulting in varying degrees of bonding between the material and oxygen within the oxide layer. Consequently, the oxidation rate varies along different directions when oxidizing inwards from the first and second trenches, leading to different oxidation rates and thus different oxidized regions. Simultaneously, the positions of the first and second connectors hinder oxygen penetration into the oxide layer, affecting the corresponding oxidation rate and consequently the oxidized region. Under the influence of crystal anisotropy on the oxidation rate and the interaction of the oxidation rates of the first and second connectors, the oxide aperture includes a first, second, third, and fourth oxidation arc. The first and second oxidation arcs are positioned opposite each other, as are the third and fourth. The third and fourth oxidation arcs have different radii of curvature, forming a specific irregular morphology. This irregular morphology of the oxide aperture effectively suppresses transverse multimode lasing of optical signals and reduces mode degeneracy.

[0014] In some embodiments, the refractive index of the oxide hole is greater than that of the first oxide region, and the conductivity of the oxide hole is greater than that of the first oxide region.

[0015] The first oxidation arc faces the first trench portion, and the second oxidation arc faces the second trench portion;

[0016] The third oxidation arc is disposed toward the first connecting portion, and the fourth oxidation arc is disposed toward the second connecting portion; the size of the first connecting portion is larger than the size of the second connecting portion.

[0017] The radius of curvature of the third oxidation arc is greater than that of the fourth oxidation arc.

[0018] The above technical solution has the following advantages or beneficial effects: Since the first oxide region is oxidized to generate a low-refractive-index, insulating oxide, while the oxide hole remains unoxidized, the refractive index of the oxide hole is greater than that of the first oxide region, and the conductivity of the oxide hole is greater than that of the first oxide region. The light field is output along the oxide hole, and charge carriers are transported along the oxide hole to the active region, thereby producing a high-efficiency photoelectric confinement effect. The positions of the first and second connecting portions make it difficult for oxygen to enter the oxide layer, thus affecting the oxidation rate of the corresponding oxide layer and consequently affecting the oxidized area of ​​the oxide layer. Therefore, the first connecting portion forms a third oxidation arc downwards corresponding to the oxide layer position, and the second connecting portion forms a fourth oxidation arc downwards corresponding to the oxide layer position, thus forming an oxide hole with a specific morphology. Oxidation from the first trench portion inwards forms the first oxidation arc, and oxidation from the second trench portion inwards forms the second oxidation arc, so that the first oxidation arc faces the first trench portion, and the second oxidation arc faces the second trench portion. Different oxidation rates in different directions result in different oxidation regions at different locations, leading to varying inclination angles on the edges of the oxide pores. The radius of curvature of the third oxidation arc is greater than that of the fourth oxidation arc, forming oxide pores with specific irregular morphologies. During the formation of these specific morphologies, the first and second connecting portions can serve as control variables for the formation of the oxide pore's specific morphology. By combining the oxidation rate along the crystal orientation, the width and dimensions of the first and second connecting portions can be controlled until the size of the first connecting portion is greater than that of the second connecting portion, thereby adjusting the oxide pore morphology.

[0019] In some embodiments, the first trench portion and the second trench portion are configured to expose both sides of the oxide layer to oxidize the oxide layer and generate the first oxide region; at the same time, the second reflective layer is oxidized to generate the second oxide region;

[0020] The first oxide region includes aluminum oxide and arsenic oxide, the second oxide region includes aluminum oxide and arsenic oxide, and the oxide pores do not include aluminum oxide or arsenic oxide.

[0021] The above technical solution has the following advantages or beneficial effects: Etching forms a first trench and a second trench, exposing both sides of the oxide layer. The first and second trenches are in full contact with the oxidation environment, allowing oxygen inside the first and second trenches to move into the oxide layer, thus oxidizing it and forming a first oxide region. Since both sides of the second reflective layer are also exposed, the second reflective layer is oxidized, forming a second oxide region. Both the first and second oxide regions include aluminum oxide and arsenic oxide, making them low-refractive-index insulating regions. The oxide holes, however, do not contain aluminum oxide or arsenic oxide; they are high-refractive-index, highly conductive, unoxidized regions. Consequently, the light field is output along the oxide holes, and charge carriers are transported along the oxide holes to the active region, resulting in good photoelectric confinement.

[0022] In some embodiments, the first oxidation region is located between the first trench portion and the second trench portion, and the second oxidation region is located between the first trench portion and the second trench portion;

[0023] The inner contour line of the second oxide region is further away from the oxide hole than the inner contour line of the first oxide region;

[0024] The outer contours of the first oxidation zone and the second oxidation zone are both formed by the first groove portion and the second groove portion.

[0025] The above technical solution has the following advantages or beneficial effects: oxidation is performed inward along the first and second trenches, forming a first oxide region in the oxide layer and a second oxide region in the second reflective layer. Since the inner contour line of the second oxide region is further away from the oxide hole than the inner contour line of the first oxide region, the area occupied by the first oxide region is larger than that occupied by the second oxide region, resulting in a smaller oxide hole diameter, which helps reduce laser mode degeneracy.

[0026] In some embodiments, the oxide layer includes a third oxide region, and the second reflective layer includes a fourth oxide region;

[0027] The third oxidation zone is symmetrically arranged relative to the first oxidation zone, and the area enclosed by the first trench portion and the second trench portion is symmetrically arranged.

[0028] The fourth oxidation zone is symmetrically arranged relative to the second oxidation zone, and the area enclosed by the first groove portion and the second groove portion is symmetrically arranged.

[0029] The above technical solution has the following advantages or beneficial effects: The oxygen filling the first and second trenches oxidizes inwards and outwards simultaneously, forming a third oxide region in the oxide layer and a fourth oxide region in the second reflective layer. Since the third and first oxide regions are formed synchronously, they are symmetrically arranged with respect to the area enclosed by the first and second trenches. Similarly, the fourth oxide region is symmetrically arranged with respect to the second oxide region. The formation of the second and fourth oxide regions can further reduce the lateral diffusion of the light field and charge carriers, causing the light field and charge carriers to converge and concentrate at the oxide aperture.

[0030] In some embodiments, the crystal plane index of the substrate surface forms a 15° angle with its {111} crystal plane, and the crystal plane index of the oxide layer and the second reflective layer forms a 15° angle with their {111} crystal planes.

[0031] The above technical solution has the following advantages or beneficial effects: Since the crystal plane index of the substrate surface forms a 15° angle with its {111} crystal plane, the crystal plane index of the oxide layer surface also forms a 15° angle with its {111} crystal plane, thus the crystal orientation of the oxide layer is anisotropic. Based on this anisotropy, the atomic composition, spatial structure, and inter-atom layer distances differ in different crystal orientations, resulting in different degrees of bonding between the material and oxygen inside the oxide layer, which helps to form oxide pores with specific morphologies.

[0032] In some embodiments, the oxide layer and the second reflective layer each comprise AlGaAs, and the molar content of Al in the oxide layer is greater than the molar content of Al in the second reflective layer.

[0033] The above technical solution has the following advantages or beneficial effects: the oxide layer and the second reflective layer respectively comprise AlGaAs. Al and As are easily oxidized, so the oxide layer is oxidized into aluminum oxide and arsenic oxide, and the second reflective layer is oxidized into aluminum oxide and arsenic oxide. These two oxides have low refractive index and high insulation. The molar content of Al in the oxide layer is greater than that in the second reflective layer, so the oxidation rate of the oxide layer is high, the oxidation range is large, and the first oxide region extends inward a long distance, resulting in a smaller oxide aperture, which is beneficial for reducing the degeneracy of the light emission mode.

[0034] In some embodiments, a method for fabricating a laser chip is provided, comprising:

[0035] A first reflective layer, an active region, an oxide layer, and a second reflective layer are sequentially grown on the substrate surface, and the crystal plane index of the substrate surface is at a preset angle to the crystal plane.

[0036] The second reflective layer is etched downwards along its surface to above the active region to form a first trench and a second trench, thereby exposing the inner sidewalls of the oxide layer for oxidation etching. A first connection is provided between one end of the second trench and one end of the first trench, and a second connection is provided between the other end of the second trench and the other end of the first trench.

[0037] When placed in a high-temperature water vapor oxidation environment, oxygen in the first and second grooves comes into contact with the oxide layer and oxidizes the oxide layer inward. The oxidized area forms a first oxidation zone, and the unoxidized area forms an oxidation pore. The oxidation pore includes a first oxidation arc, a second oxidation arc, a third oxidation arc, and a fourth oxidation arc. The first oxidation arc and the second oxidation arc are arranged opposite to each other, and the third oxidation arc and the fourth oxidation arc are arranged opposite to each other. The radii of curvature of the third oxidation arc and the fourth oxidation arc are different.

[0038] The above technical solution has the following advantages or beneficial effects: A substrate with a surface crystal plane index at a predetermined angle to its {111} crystal plane is selected, and a first reflective layer, an active region, an oxide layer, and a second reflective layer are sequentially grown on the substrate surface. To oxidize and etch the oxide layer to form oxide holes for photoelectric confinement, etching is performed downwards along the surface of the second reflective layer to above the active region to form a first trench and a second trench, exposing both sides of the oxide layer for oxidation. To facilitate the formation of oxide holes with specific morphologies, a first connecting portion is connected between one end of the second trench and one end of the first trench, and a second connecting portion is connected between the other end of the second trench and the other end of the first trench. Placed in a high-temperature water vapor oxidation environment, the high-temperature water vapor in the first and second trenches contacts and oxidizes the oxide layer, oxidizing it according to different crystal orientations. The oxidized area forms a first oxide region, and the unoxidized area forms an oxide hole, which is surrounded by the first oxide region. The first oxide region is a low-refractive-index, insulating oxide layer, while the oxide holes are high-refractive-index, high-conductivity, unoxidized regions. Consequently, the light field is output along the oxide holes, and charge carriers are transported to the active region along these holes, exhibiting good photoelectric confinement performance. The oxide holes confine the light and electric fields vertically, reducing lateral diffusion of light and charge carriers. During the formation of oxide holes with specific morphologies, since the crystal plane indices of the substrate surface and its {111} crystal plane form a predetermined angle, the crystal plane indices of the oxide layer surface and its {111} crystal plane also form a predetermined angle, resulting in anisotropy of the oxide layer's crystal orientation. This anisotropy leads to differences in atomic composition, spatial structure, and interlayer distances in different crystal orientations, resulting in varying degrees of bonding between the material and oxygen within the oxide layer. Consequently, the oxidation rate differs along different directions when oxidizing inwards from the first and second trenches, leading to different oxidation rates within the oxide layer and thus different oxidized regions. Meanwhile, the positions of the first and second connecting portions make it difficult for oxygen to enter the oxide layer, thus affecting the oxidation rate of the corresponding oxide layer and consequently the oxidized area. Due to the influence of crystal anisotropy on the oxidation rate, and the mutual coordination of the oxidation rates of the first and second connecting portions, the oxide aperture includes a first oxide arc, a second oxide arc, a third oxide arc, and a fourth oxide arc. The first and second oxide arcs are positioned opposite each other, as are the third and fourth oxide arcs. The third and fourth oxide arcs have different radii of curvature, forming a specific irregular morphology. Based on this irregular morphology, the oxide aperture can effectively suppress transverse multimode lasing of optical signals and reduce mode degeneracy.

[0039] In some embodiments, the refractive index of the oxide hole is greater than that of the first oxide region, and the conductivity of the oxide hole is greater than that of the first oxide region.

[0040] The first oxidation arc faces the first trench portion, and the second oxidation arc faces the second trench portion;

[0041] The third oxidation arc is disposed toward the first connecting portion, and the fourth oxidation arc is disposed toward the second connecting portion; the size of the first connecting portion is larger than the size of the second connecting portion.

[0042] The radius of curvature of the third oxidation arc is greater than that of the fourth oxidation arc.

[0043] The above technical solution has the following advantages or beneficial effects: Since the first oxide region is oxidized to generate a low-refractive-index, insulating oxide, while the oxide hole remains unoxidized, the refractive index of the oxide hole is greater than that of the first oxide region, and the conductivity of the oxide hole is greater than that of the first oxide region. The light field is output along the oxide hole, and charge carriers are transported along the oxide hole to the active region, thereby producing a high-efficiency photoelectric confinement effect. The positions of the first and second connecting portions make it difficult for oxygen to enter the oxide layer, thus affecting the oxidation rate of the corresponding oxide layer and consequently affecting the oxidized area of ​​the oxide layer. Therefore, the first connecting portion forms a third oxidation arc downwards corresponding to the oxide layer position, and the second connecting portion forms a fourth oxidation arc downwards corresponding to the oxide layer position, thus forming an oxide hole with a specific morphology. Oxidation from the first trench portion inwards forms the first oxidation arc, and oxidation from the second trench portion inwards forms the second oxidation arc, so that the first oxidation arc faces the first trench portion, and the second oxidation arc faces the second trench portion. Different oxidation rates in different directions result in different oxidation regions at different locations, leading to varying inclination angles on the edges of the oxide pores. The radius of curvature of the third oxidation arc is greater than that of the fourth oxidation arc, forming oxide pores with specific irregular morphologies. During the formation of these specific morphologies, the first and second connecting portions can serve as control variables for the formation of the oxide pore's specific morphology. By combining the oxidation rate along the crystal orientation, the width and dimensions of the first and second connecting portions can be controlled until the size of the first connecting portion is greater than that of the second connecting portion, thereby adjusting the oxide pore morphology.

[0044] In some embodiments, oxygen in the first and second trenches comes into contact with the second reflective layer and oxidizes the second reflective layer to form a second oxidation zone.

[0045] The above technical solution has the following advantages or beneficial effects: Since both sides of the second reflective layer are also exposed, the second reflective layer is oxidized to form a second oxide region. The second oxide region is also a low refractive index, insulating oxide region, which is beneficial to further confine the light field and electric field in the vertical direction and reduce the lateral diffusion of the light field and charge carriers.

[0046] In some embodiments, the first oxidation region is located on the inner side between the first trench portion and the second trench portion;

[0047] The second oxidation zone is located on the inner side between the first trench portion and the second trench portion;

[0048] The inner contour line of the second oxide region is further away from the oxide hole than the inner contour line of the first oxide region;

[0049] The outer contours of the first oxidation zone and the second oxidation zone are both formed by the first groove portion and the second groove portion.

[0050] The above technical solution has the following advantages or beneficial effects: oxidation is performed inward along the first and second trenches, forming a first oxide region in the oxide layer and a second oxide region in the second reflective layer. Since the inner contour line of the second oxide region is further away from the oxide hole than the inner contour line of the first oxide region, the area occupied by the first oxide region is larger than that occupied by the second oxide region, resulting in a smaller oxide hole diameter, which helps reduce laser mode degeneracy.

[0051] In some embodiments, the oxide layer includes a third oxide region, and the second reflective layer includes a fourth oxide region;

[0052] The third oxidation zone is symmetrically arranged relative to the first oxidation zone, and the area enclosed by the first trench portion and the second trench portion is symmetrically arranged.

[0053] The fourth oxidation zone is symmetrically arranged relative to the second oxidation zone, and the area enclosed by the first groove portion and the second groove portion is symmetrically arranged.

[0054] The above technical solution has the following advantages or beneficial effects: The oxygen filling the first and second trenches oxidizes inwards and outwards simultaneously, forming a third oxide region in the oxide layer and a fourth oxide region in the second reflective layer. Since the third and first oxide regions are formed synchronously, they are symmetrically arranged with respect to the area enclosed by the first and second trenches. Similarly, the fourth oxide region is symmetrically arranged with respect to the second oxide region. The formation of the second and fourth oxide regions can further reduce the lateral diffusion of the light field and charge carriers, causing the light field and charge carriers to converge and concentrate at the oxide aperture.

[0055] In some embodiments, the oxide layer and the second reflective layer each comprise AlGaAs, and the molar content of Al in the oxide layer is greater than the molar content of Al in the second reflective layer.

[0056] The above technical solution has the following advantages or beneficial effects: the oxide layer and the second reflective layer respectively comprise AlGaAs. Al and As are easily oxidized, so the oxide layer is oxidized into aluminum oxide and arsenic oxide, and the second reflective layer is oxidized into aluminum oxide and arsenic oxide. These two oxides have low refractive index and high insulation. The molar content of Al in the oxide layer is greater than that in the second reflective layer, so the oxidation rate of the oxide layer is high, the oxidation range is large, and the first oxide region extends inward a long distance, resulting in a smaller oxide aperture, which is beneficial for reducing the degeneracy of the light emission mode. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure.

[0058] Figure 1 This is a partial architecture diagram of an optical communication system according to some embodiments;

[0059] Figure 2 This is a partial structural diagram of a host computer according to some embodiments;

[0060] Figure 3 This is a structural diagram of an optical module according to some embodiments;

[0061] Figure 4 An exploded view of an optical module according to some embodiments;

[0062] Figure 5 This is a structural diagram of the internal structure of an optical module according to some embodiments;

[0063] Figure 6 This is an exploded view of the internal structure of an optical module according to some embodiments;

[0064] Figure 7 An internal cross-sectional structure of an optical module according to some embodiments Figure 1 ;

[0065] Figure 8 An internal cross-sectional structure of an optical module according to some embodiments Figure 2 ;

[0066] Figure 9 An internal cross-sectional structure of an optical module according to some embodiments Figure 3 ;

[0067] Figure 10 This is a cross-sectional structural diagram of a laser chip according to some embodiments;

[0068] Figure 11 This is a partial top view of a laser chip according to some embodiments;

[0069] Figure 12 This is a schematic diagram of an oxide pore morphology structure according to some embodiments;

[0070] Figure 13 This is a flowchart of a method for fabricating a laser chip according to some embodiments;

[0071] Figure 14 This is a schematic diagram of a laser chip array emitting light according to some embodiments;

[0072] Figure 15 This is a cross-sectional view of another laser chip structure according to some embodiments;

[0073] Figure 16 This is a partial top view of another laser chip structure according to some embodiments;

[0074] Figure 17 This is a diagram of the internal structure of another laser chip according to some embodiments;

[0075] Figure 18 This is a flowchart of another method for fabricating a laser chip according to some embodiments. Detailed Implementation

[0076] The embodiments of this disclosure will now be described clearly and in detail with reference to the accompanying drawings. However, the described embodiments are merely some, and not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0077] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and inclusive, meaning "including, but not limited to"; the terms "first" and "second" should not be construed as indicating or implying relative importance or indicating an upper limit on the number; the term "multiple" means two or more; the term "connection" should be interpreted broadly, for example, "connection" can be a fixed connection, a detachable connection, or an integral part, and can be a direct connection or an indirect connection through an intermediate medium; the use of the terms "applicable to" or "configured to" implies open and inclusive language, which does not exclude applicability to or configuration to devices performing additional tasks or steps; descriptions such as "parallel," "perpendicular," "identical," "consistent," and "aligned" are not limited to absolute mathematical theoretical relationships, but also include acceptable error ranges arising in practice, and differences based on the same design concept but due to manufacturing reasons.

[0078] In optical communication technology, to establish information transmission between information processing devices, information is loaded onto light, and the speed of light propagation is used to transmit the information. This light carrying information is called an optical signal. When optical signals are transmitted in optical information transmission equipment, optical power loss can be reduced, enabling long-distance transmission of optical signals. At the same time, the cost of optical information transmission equipment such as optical fibers is lower than that of electrical information transmission equipment such as copper wires. Therefore, optical communication technology can achieve high-speed, long-distance, and low-cost information transmission.

[0079] Information processing equipment typically includes optical network units (ONUs), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., while optical information transmission equipment typically includes optical fibers and optical waveguides. Information processing equipment can only recognize and process electrical signals, while optical communication technology uses optical signals for transmission, requiring optical modules to convert between optical and electrical signals.

[0080] An optical module enables the conversion between optical signals and electrical signals between information processing equipment and optical information transmission equipment. In some embodiments, at least one of the optical signal input or output terminals of the optical module is connected to an optical fiber, and at least one of the electrical signal input or output terminals of the optical module is connected to an optical network terminal. A first optical signal from the optical fiber is transmitted to the optical module, which converts the first optical signal into a first electrical signal and transmits the first electrical signal to the optical network terminal. A second electrical signal from the optical network terminal is transmitted to the optical module, which converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber.

[0081] Since multiple information processing devices can transmit information via electrical signals, at least one of these devices needs to be directly connected to the optical module, rather than all of them. Here, the information processing device directly connected to the optical module is also referred to as the host computer of the optical module. Furthermore, the optical signal input or output terminal of the optical module is called the optical port, and the electrical signal input or output terminal is called the electrical port.

[0082] Figure 1 This is a partial structural diagram of an optical communication system according to some embodiments. Figure 1 As shown, the optical communication system mainly includes a remote information processing device 1000, a local information processing device 2000, a host computer 100 for optical modules, an optical module 200, an optical fiber 101, and a network cable 103. Among them, the optical fiber 101 is an optical information transmission device, and the network cable 103 is an electrical information transmission device.

[0083] In some embodiments, one end of the optical fiber 101 extends toward the remote information processing device 1000, and the other end of the optical fiber 101 is connected to the optical module 200 through the optical port of the optical module 200. The optical signal can undergo total internal reflection in the optical fiber 101, and the propagation of the optical signal in the direction of total internal reflection can almost maintain the original optical power. The optical signal undergoes multiple total internal reflections in the optical fiber 101 to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or to transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance information transmission based on low power loss.

[0084] The optical communication system includes one or more optical fibers 101. In some embodiments, the optical fiber 101 is detachably connected to the optical module 200; in some embodiments, the optical fiber 101 is non-detachably connected to the optical module 200.

[0085] The host computer 100 is configured to provide data signals to the optical module 200, or receive data signals from the optical module 200, or monitor or control the working status of the optical module 200.

[0086] The host computer 100 includes a housing for accommodating the optical module 200, and an optical module interface 102 disposed on the housing. The optical module 200 is inserted into the housing through the optical module interface 102 to establish a unidirectional or bidirectional electrical signal connection between the host computer 100 and the optical module 200.

[0087] The host computer 100 also includes an external power interface that can connect to an electrical signal network. In some embodiments, the external power interface includes a Universal Serial Bus (USB) interface or a network cable interface 104. The network cable interface 104 is configured to connect a network cable 103 to establish a unidirectional or bidirectional electrical signal connection between the host computer 100 and the network cable 103.

[0088] One end of the network cable 103 is connected to the local information processing device 2000, and the other end is connected to the host computer 100, so as to establish an electrical signal connection between the local information processing device 2000 and the host computer 100 through the network cable 103. In some embodiments, a third electrical signal emitted by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103. The host computer 100 generates a second electrical signal based on the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200. The optical module 200 converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber 101. The second optical signal is transmitted in the optical fiber 101 to the remote information processing device 1000.

[0089] In some embodiments, a first optical signal from a remote information processing device 1000 is transmitted through an optical fiber 101, and the first optical signal from the optical fiber 101 is transmitted to an optical module 200. The optical module 200 converts the first optical signal into a first electrical signal, and transmits the first electrical signal to a host computer 100. The host computer 100 generates a fourth electrical signal based on the first electrical signal and transmits the fourth electrical signal to a local information processing device 2000.

[0090] In some embodiments, the optical module is a tool for converting optical signals to electrical signals. During the conversion process, the information does not change, but the encoding or decoding method of the information changes.

[0091] In addition to optical network terminals, the host computer 100 also includes optical line terminals (OLTs), optical network equipment (ONTs), or data center servers.

[0092] Figure 2 This is a partial structural diagram of a host computer according to some embodiments. To clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 Only the structure of the host computer 100 related to the optical module 200 is shown. For example... Figure 2As shown, in some embodiments, the host computer 100 further includes a PCB circuit board 105 disposed in the receiving cavity, and a cage 106 disposed on the surface of the PCB circuit board 105; the optical module 200 is inserted into the cage 106 and fixed by the cage 106.

[0093] In some embodiments, a heat sink 107 is provided on the cage 106 to dissipate heat for the optical module; in some embodiments, the heat sink 107 has protruding structures such as fins to increase the heat dissipation area.

[0094] In some embodiments, an electrical connector is provided inside the cage 106, which is configured to connect to the electrical port of the optical module 200.

[0095] In some embodiments, the optical module 200 is inserted into the cage 106 of the host computer 100, and the cage 106 fixes the optical module 200. The heat generated by the optical module 200 is conducted to the cage 106 and then diffused through the heat sink 107.

[0096] In some embodiments, the optical module 200 is inserted into the cage 106 of the host computer 100, and the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, thereby establishing an electrical signal connection between the optical module 200 and the host computer 100.

[0097] In some embodiments, the optical port of the optical module 200 is connected to the optical fiber 101, thereby enabling the optical module 200 to establish an optical signal connection with the optical fiber 101.

[0098] Figure 3 This is a structural diagram of an optical module according to some embodiments. Figure 4 This is an exploded view of an optical module according to some embodiments. Figure 3 and Figure 4 As shown, in some embodiments, the optical module 200 includes a shell, which comprises an upper shell 201 and a lower shell 202. The upper shell 201 covers the lower shell 202, forming two openings 204 and 205, one of which is an electrical port and the other is an optical port. In some embodiments, the shell forms an opening that serves as both an electrical port and an optical port.

[0099] In some embodiments, the upper housing 201 and the lower housing 202 are made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0100] The assembly method of combining the upper housing 201 and the lower housing 202 facilitates the installation of circuit boards 300 and other components into the housing. The upper housing 201 and the lower housing 202 can encapsulate and protect the aforementioned devices.

[0101] The direction of the line connecting the two openings 204 and 205 can be consistent with or inconsistent with the length direction of the optical module 200. For example, opening 204 is located at the end of the optical module 200. Figure 3 The opening 205 is also located at the end of the optical module 200 (right end). Figure 3 (The left end). Alternatively, opening 204 is located at the end of optical module 200, while opening 205 is located on the side of optical module 200.

[0102] In some embodiments, the lower housing 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and perpendicular to the base plate 2021; the upper housing 201 includes a cover plate 2011, which covers the two lower side plates 2022 of the lower housing 202 to form the aforementioned housing.

[0103] In some embodiments, the lower housing 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and perpendicular to the base plate 2021; the upper housing 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and perpendicular to the cover plate 2011. The two upper side plates and the two lower side plates 2022 are combined to realize that the upper housing 201 covers the lower housing 202.

[0104] like Figure 3 and Figure 4 As shown, in some embodiments, the optical module includes a circuit board 300 disposed within a housing. The circuit board 300 includes circuit traces, electronic components, and chips, etc. The electronic components and chips are connected according to the circuit design through the circuit traces to realize functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include microcontroller units (MCUs), laser driver chips, transimpedance amplifiers (TIAs), limiting amplifiers (LAs), clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0105] In some embodiments, the circuit board includes a rigid circuit board, which, due to its relatively rigid material, can also serve a load-bearing function, such as being able to stably support the aforementioned electronic components and chips; the rigid circuit board can also be inserted into an electrical connector in the cage 106 of the host computer 100.

[0106] In some embodiments, the circuit board further includes a flexible circuit board, which can be used independently or in conjunction with a rigid circuit board.

[0107] In some embodiments, the circuit board further includes gold fingers formed on its end surface, the gold fingers consisting of a plurality of independent pins.

[0108] In some implementations, the gold fingers 301 are disposed on one side of the surface of the circuit board 300 (e.g., Figure 4 (as shown on the upper surface); In some implementations, the gold fingers 301 are disposed on the upper and lower surfaces of the circuit board 300 to provide a greater number of pins, thereby adapting to situations where the number of pins is required.

[0109] In some implementations, the gold fingers of the circuit board extend from the opening 204 and are inserted into the electrical connector of the host computer 100; the circuit board is inserted into the cage 106, and the gold fingers 301 are connected to the electrical connector inside the cage 106. The gold fingers 301 are configured to establish an electrical connection with the host computer, enabling electrical connection functions such as power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, and data signal transmission.

[0110] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside its housing. The unlocking component 600 is configured to establish a fixed connection between the optical module 200 and the host computer, or to release the fixed connection between the optical module 200 and the host computer.

[0111] For example, the unlocking component 600 is located on the outside of the two lower side plates 2022 of the lower housing 202, and includes a locking component that matches the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the locking component of the unlocking component 600 fixes the optical module 200 in the cage 106; when the unlocking component 600 is pulled, the locking component of the unlocking component 600 moves accordingly, thereby changing the connection relationship between the locking component and the host computer, so as to release the fixation between the optical module 200 and the host computer, thereby allowing the optical module 200 to be pulled out of the cage 106.

[0112] In some embodiments, the optical module may include a lens assembly 400. The lens assembly 400 is projected onto the surface of the circuit board 300.

[0113] In some embodiments, the optical module may include an optical fiber support 410. An optical fiber ribbon 420 is fixed inside the optical fiber support 410.

[0114] In some embodiments, the lens assembly 400 is assembled and connected to the fiber optic bracket 410 so that the lens assembly 400 is optically coupled to the fiber optic ribbon 420, thereby inputting / outputting optical signals to the lens assembly 400 through the fiber optic ribbon 420.

[0115] Figure 5 This is a diagram illustrating the internal structure of an optical module according to some embodiments. Figure 6 This is an exploded view of the internal structure of an optical module according to some embodiments. For example... Figure 5 and Figure 6 As shown, in some embodiments, the lens assembly 400 is located on the surface of the circuit board 300 and is located on one side of the DSP chip 302.

[0116] In some embodiments, the surface of the circuit board 300 is provided with a photodetector 320, a laser chip 500, a TIA 330, and a laser driver chip 310.

[0117] In some embodiments, photodetector 320 and TIA 330 are arranged adjacent to each other. Photodetector 320 is used to convert the received optical signal into a photocurrent signal, and TIA 330 is used to convert the photocurrent signal into a voltage signal and amplify the voltage signal. The processed electrical signal is transmitted to DSP chip 302.

[0118] In some embodiments, the laser chip 500 and the laser driver chip 310 are arranged adjacent to each other. The laser driver chip 310 is used to generate a drive signal based on the digital signal output by the DSP chip 302. The drive signal is transmitted to the laser chip 500, and the laser chip 500 converts the received electrical signal into an optical signal under the action of the drive signal.

[0119] In some embodiments, the lens assembly 400 is disposed on the surface of the photodetector 320, TIA 330, laser chip 500, and laser driver chip 310.

[0120] In some embodiments, the light receiving direction of the photodetector 320 is perpendicular to the surface of the circuit board 300, and the transmission direction of the optical fiber ribbon in the optical fiber support 410 is parallel to the surface of the circuit board 300. Therefore, the lens assembly 400 has an optical path reversal function to reverse the transmission direction of the optical signal transmitted in the optical fiber ribbon in the optical fiber support 410 from being parallel to the surface of the circuit board 300 to being perpendicular to the circuit board 300, so as to transmit it into the photodetector 320.

[0121] In some embodiments, the laser chip 500 emits light perpendicular to the surface of the circuit board 300, emitting light upwards perpendicular to the circuit board 300. The fiber optic ribbon in the fiber optic bracket 410 transmits light parallel to the surface of the circuit board 300. Therefore, the lens assembly 400 has an optical path reversal function, reversing the transmission direction of the light signal emitted upwards from the laser chip 500 along the surface of the circuit board 300 to be parallel to the surface of the circuit board 300, thereby coupling it into the fiber optic ribbon in the fiber optic bracket 410 for transmission.

[0122] Figure 7 An internal cross-sectional structure of an optical module according to some embodiments Figure 1 , Figure 8 An internal cross-sectional structure of an optical module according to some embodiments Figure 2 .like Figure 7 and Figure 8 In some embodiments, a reflective surface 401 is formed on the surface of the lens assembly 400. The reflective surface 401 is configured as an inclined surface. The reflective surface 401 can reflect light signals incident on its surface.

[0123] In some embodiments, the laser chip 500 is located below the reflective surface 401. The fiber optic bracket 410 is located on the reflected light path of the reflective surface 401.

[0124] In some embodiments, the laser chip 500 emits light upwards perpendicular to the surface of the circuit board 300, which is incident on the first reflective surface 401. The first reflective surface 401 reflects the light emitted by the laser chip 500 parallel to the surface of the circuit board 300, so as to couple it into the fiber optic bracket 410, thereby realizing the transmission of optical signals.

[0125] In some embodiments, the laser chip 500 can be a vertical cavity surface emitting laser (VCSEL). A VCSEL laser chip is a semiconductor laser whose light emission direction is perpendicular to the pn junction plane and whose resonant cavity surface is parallel to the pn junction plane.

[0126] In some embodiments, to improve the transmission rate, multiple independent laser chips 500 can be configured to emit multiple beams of light signals, thereby achieving multi-channel transmission. For example, the laser chip 500 is a 1×1 type chip.

[0127] Figure 9 An internal cross-sectional structure of an optical module according to some embodiments Figure 3 .like Figure 9 As shown, in some embodiments, the laser chip 500 can be a 1×N array packaged chip to achieve multi-channel transmission and improve the transmission rate. For example, if the laser chip 500 is a 1×4 array packaged chip, it will emit 4 beams of light signals to achieve four-channel transmission.

[0128] Figure 10 This is a cross-sectional view of a laser chip according to some embodiments. Figure 11 This is a partial top view of a laser chip according to some embodiments. Figure 10 and Figure 11 As shown, in some embodiments, the laser chip 500 can be a 1×1 type chip. Wherein, Figure 10 It is along Figure 11 The structural diagram obtained by cross-sectioning along the dashed lines shown.

[0129] In some embodiments, the laser chip 500 may include a substrate 510. The substrate 510 is located at the bottom. Exemplarily, the substrate 510 may be a highly doped GaAs layer. The light emission direction of the laser chip 500 is perpendicular to the surface of the substrate 510.

[0130] In some embodiments, the laser chip 500 may include a first reflective layer 520. The first reflective layer 520 may be an N-type distributed Bragg reflector (N-DBR) layer. The first reflective layer 520 is located above the substrate 510. The first reflective layer 520 is an N-type doped distributed Bragg reflector. The first reflective layer 520 is composed of Al atoms with different refractive indices. x Ga 1-x The material is composed of stacked aluminum layers. The refractive index can be controlled by changing the aluminum composition. It consists of two layers of Al, one with a high refractive index and the other with a low refractive index. x Ga 1-x As a medium, a pair of DBRs are formed. The large difference in refractive index between each pair of DBRs is used to obtain a high reflectivity.

[0131] In some embodiments, the laser chip 500 may include an active region 530. The active region 530 is located above the first reflective layer 520. The active region 530 includes quantum wells to provide optical gain. Selecting a quantum well layer with a high crystal orientation index yields a better band structure, which is beneficial for carriers to form higher gain and differential gain at the target wavelength, resulting in higher optical power and modulation rate.

[0132] In some embodiments, the laser chip 500 may include an oxide layer 540. The oxide layer 540 is located above the active region 530. The oxide layer 540 may be AlGaAs with a high Al content. If Al is selected... 0.98 Ga 0.02As serves as the oxide layer 540. Al and As elements are easily oxidized. Oxidation of the oxide layer 540 achieves optical and electric field confinement. The oxidized regions form low-refractive-index, insulating oxides. The oxides surround the unoxidized regions. The low refractive index of the oxides provides optical field confinement, and the high insulation provides current confinement. The oxides include insulating aluminum oxide (AlxOy) and a small amount of arsenic oxide. In some embodiments, the optical signal generated by the laser chip 500 is output from the oxide aperture 541 in a direction perpendicular to the surface of the substrate 510.

[0133] In some embodiments, the laser chip 500 may include a second reflective layer 550. The second reflective layer 550 may be a P-type distributed Bragg reflector (P-DBR) layer. The second reflective layer 550 is a P-type doped distributed Bragg reflector. The second reflective layer 550 is located above the oxide layer 540. The second reflective layer 550 is also composed of Al with different refractive indices. x Ga 1-x As a stacked composition. The refractive index of the material can be controlled by changing the aluminum composition. A pair of DBRs consists of two dielectric layers, one with a high refractive index and the other with a low refractive index. The large refractive index difference in each pair of DBRs results in higher reflectivity.

[0134] In some embodiments, the laser chip 500 may include a P-type metal electrode layer 580. The P-type metal electrode layer 580 is electrically connected to the second reflective layer 550.

[0135] In some embodiments, the laser chip 500 may include an N-type metal electrode layer 590. The N-type metal electrode layer 590 is electrically connected to the first reflective layer 520.

[0136] In some embodiments, metal electrode layers are deposited using electron beam evaporation. The P-type metal electrode layer 580 is made of Ti / Pt / Au, and the N-type metal electrode layer 590 is made of Au / Ge / Ni. Ti is used to increase the adhesion between the electrode and the semiconductor material. The change from a Schottky barrier contact to an ohmic contact between the Au alloy and n-GaAs is achieved through Ge atoms.

[0137] In some embodiments, the second reflective layer 550, the active region 530, and the first reflective layer 520 are arranged in a vertical direction.

[0138] In some embodiments, the second reflective layer 550 provides P-type charge carriers downward to the active region 530, and the first reflective layer 520 provides N-type charge carriers upward to the active region 530. P-type and N-type charge carriers are injected into the active region 530, resulting in radiative recombination and the release of photons. Exemplarily, the P-type charge carriers are holes, and the N-type charge carriers are electrons.

[0139] In some embodiments, the second reflective layer 550, the active region 530, and the first reflective layer 520 constitute an FP resonant cavity with a resonant cavity mode, allowing only light near the cavity mode to pass through. The second reflective layer 550 and the first reflective layer 520 each have high reflectivity. Photons pass through the resonant cavity, and a specific oscillation mode is selected and fed back multiple times between the second reflective layer 550 and the first reflective layer 520 to form laser oscillation, thereby generating laser light. A corresponding modulated optical signal is generated by modulating an electrical signal.

[0140] In some embodiments, the recombination rate of P-type and N-type carriers within the active region 530 can be controlled by varying the magnitude of the current injected into the active region 530. Increasing the current leads to more recombination of P-type and N-type carriers, thereby generating more photons and increasing the intensity of the laser beam. Conversely, decreasing the current results in a decrease in the intensity of the laser beam. This intensity modulation generates an optical signal. Ultimately, the optical signal is output in a direction perpendicular to the surface of the substrate 510, forming a vertical-cavity laser emission.

[0141] In some embodiments, in order to reduce optical loss, the first reflective layer 520 has a reflectivity close to 100% and can be used as a total reflection mirror of the resonant cavity, while the second reflective layer 550 has a relatively low reflectivity and can be used as an exit mirror of the resonant cavity.

[0142] In some embodiments, when the oxide layer 540 is oxidized, a low-refractive-index, insulating oxide is formed in the oxidized area, while an oxide hole 541 with a certain morphology is formed in the unoxidized area. The oxide hole 541 is surrounded by oxide. Since the oxide hole 541 is not oxidized, its refractive index is relatively greater than that of the oxidized aluminum oxide (AlxOy) and arsenic oxide. The conductivity of the oxide hole 541 is also higher than that of the oxidized aluminum oxide (AlxOy) and arsenic oxide. It can be understood that the oxide hole 541 is not a hollow hole; it is simply that because it is not oxidized, light and electric fields are concentrated and can pass through, hence the figurative term "hole".

[0143] In some embodiments, the light field and charge carriers flow through the unoxidized oxide holes 541, confining the light field and charge carriers in the vertical direction, reducing the influence of lateral charge carrier and light field diffusion, and forming a photoelectric convergence structure in the active region 530 to achieve a high-efficiency photoelectric confinement effect.

[0144] In some embodiments, to better confine the optical field and charge carriers, the oxide layer 540 cannot be located too far from the active region 530. Nor can the oxide layer 540 be located too close to the active region 530. When the oxide layer 540 is too close to the active region 530, oxidation shrinkage has a greater impact on the active region 530, and the absorption loss of photoelectric signals is also greater. For example, the oxide layer 540 can be placed on the first phase layer of the active region 530.

[0145] In some embodiments, the oxide aperture area of ​​the high-speed VCSEL laser chip is in the range of 5µm to 7µm in diameter, which makes lateral single-mode lasing impossible. For high-speed VCSELs, lateral multimode lasing can be effectively suppressed and mode degeneracy reduced by forming oxide apertures 541 with specific irregular morphologies. Exemplarily, this disclosure provides oxide apertures 541 with a diameter of 4µm to 6µm.

[0146] In some embodiments, to oxidize and etch the oxide layer 540 to form oxide holes 541 with a specific morphology, the laser chip 500 may include a first trench portion 560 and a second trench portion 570. The first trench portion 560 extends downward along the second reflective layer 550 above the active region 530, exposing one sidewall of the interior of the oxide layer 540. The second trench portion 570 extends downward along the second reflective layer 550 above the active region 530, exposing the other sidewall of the interior of the oxide layer 540.

[0147] In some embodiments, the first trench portion 560 and the second trench portion 570 are disposed opposite to each other. The first trench portion 560 and the second trench portion 570 may each be an arc-shaped trench portion to form an oxide hole 541 morphology. The two arc-shaped trench portions face the same center.

[0148] In some embodiments, the oxide layer 540 is oxidized and etched in a high-temperature water vapor environment. The first trench portion 560 and the second trench portion 570 are in full contact with the high-temperature water vapor. The high-temperature water vapor in the first trench portion 560 and the second trench portion 570 diffuses inward, thereby oxidizing the oxide layer 540 inward. At high temperature, Al and As react with water, and the water is decomposed into oxygen by the high temperature, thereby Al and As are oxidized to form insulating oxides with low refractive index.

[0149] In some embodiments, the crystal plane index of the substrate 510 forms a 15° angle with its {111} crystal plane. Similarly, the crystal plane index of each layer above the substrate 510, such as the oxide layer 540 and the second reflective layer 550, also forms a 15° angle with its {111} crystal plane. Consequently, the crystal orientations of the oxide layer 540 and the second reflective layer 550 exhibit anisotropy. This anisotropy results in different atomic compositions, spatial structures, and interlayer distances in different crystal orientations, leading to different degrees of bonding between the material inside the oxide layer 540 and oxygen. Therefore, when oxidizing inwards from the first trench portion 560 and the second trench portion 570, the oxidation rate varies along different directions. The different oxidation rates of the material inside the oxide layer 540 result in different oxidized areas and ranges.

[0150] In some embodiments, a crystal plane with a crystal orientation index of 111 or higher is used as a substrate for growing a first reflective layer 520, a quantum well, an oxide layer, etc.

[0151] In some embodiments, to facilitate the formation of oxide holes 541 with a specific morphology, a first connecting portion 561 is connected between one end of the first trench portion 560 and one end of the second trench portion 570, and a second connecting portion 562 is connected between the other end of the first trench portion 560 and the other end of the second trench portion 570. That is, when etching is performed to form the first trench portion 560 and the second trench portion 570, the first connecting portion 561 and the second connecting portion 562 are not etched away, but are retained.

[0152] In some embodiments, the first trench portion 560, the first connecting portion 561, the second trench portion 570, and the second connecting portion 562 form a closed loop to form a closed-loop oxide hole 541. The surfaces of the first connecting portion 561 and the second connecting portion 562 are respectively higher than the groove surface of the first trench portion 560. Exemplarily, the first trench portion 560 is a C-shaped trench with a certain depth facing the oxide hole 541 from one side, and the second trench portion 570 is also a C-shaped trench with a certain depth facing the oxide hole 541 from the opposite side. The ends of the two C-shaped trenches are respectively connected to the second connecting portion 562 via the first connecting portion 561.

[0153] In some embodiments, the anisotropic crystal orientation of the oxide layer 540 results in different atomic compositions, spatial structures, and interlayer distances, leading to varying degrees of bonding between the material and oxygen within the oxide layer. Consequently, the oxidation rate differs along different directions when oxidizing inwards from the first trench 560 and the second trench 570, resulting in different oxidation rates within the oxide layer and thus different oxidized areas. Simultaneously, the positions of the first connecting portion 561 and the second connecting portion 562 make it difficult for oxygen to enter the oxide layer, thereby affecting the oxidation rate of the corresponding oxide layer 540 and consequently the oxidized area of ​​the oxide layer 540. By combining the influence of crystal anisotropy on the oxidation rate with the combined influence of the first connecting portion 561 and the second connecting portion 562, a specific morphology of the oxide hole 541 can be formed. This effectively suppresses transverse multimode laser lasing and reduces mode degeneracy.

[0154] In some embodiments, the oxidation rate is controlled by the anisotropy of the crystal orientation and the cooperation of the first connection portion 561 and the second connection portion 562, thereby controlling the morphology of the oxide hole 541, forming an irregular morphology, effectively suppressing laser transverse multimode lasing, and reducing mode degeneracy.

[0155] It is understandable that the morphology of the oxide hole 541 is due to the anisotropy of the crystal orientation, as well as the influence and balance between the first connection portion 561 and the second connection portion 562 on the oxidation rate of the crystal orientation.

[0156] Figure 12 This is a schematic diagram of an oxide pore morphology structure according to some embodiments. For example... Figure 12 As shown, in some embodiments, due to the anisotropy of the crystal orientation of the oxide layer 540, and the cooperation of the first connecting portion 561 and the second connecting portion 562, an oxide hole 541 with a specific irregular morphology is formed.

[0157] In some embodiments, the oxide aperture 541 includes a first oxide arc 5411 and a second oxide arc 5412. The oxide aperture 541 is asymmetrically arranged with respect to the line connecting the first oxide arc 5411 and the second oxide arc 5412, forming a specific irregular morphology. The oxide aperture based on the irregular morphology can effectively suppress transverse multimode laser lasing and reduce mode degeneracy.

[0158] In some embodiments, the first oxidation arc 5411 faces the first trench portion 560. The second oxidation arc 5412 faces the second trench portion 570. Exemplarily, the first oxidation arc 5411 may face the center of the first trench portion 560, and the second oxidation arc 5412 may face the center of the second trench portion 570. The oxidation rate corresponding to the crystal direction where the center of the first trench portion 560 is located is small, thereby forming the first oxidation arc 5411. Similarly, on the opposite side, the oxidation rate corresponding to the crystal direction where the center of the second trench portion 570 is located is small, thereby forming the second oxidation arc 5412.

[0159] In some embodiments, the oxide hole 541 includes a third oxide arc 5413 and a fourth oxide arc 5414. The third oxide arc 5413 is disposed toward the first connecting portion 561. The fourth oxide arc 5414 is disposed toward the second connecting portion 562.

[0160] In some embodiments, the oxide hole 541 includes a major axis and a minor axis. Compared to a circular or elliptical shape, the ratio of the major axis to the minor axis length of the oxide hole 541 is increased, thereby compressing the number of transverse modes and suppressing transverse multimode laser lasing. Exemplarily, the oxide hole 541 has a shield-like morphology.

[0161] In some embodiments, the oxidation rate along the crystal direction from the first connecting portion 561 to the center of the oxide hole 541 is high, while the oxidation rate along the crystal direction from the second connecting portion 562 to the hollow part of the oxide hole 541 is low. The arrangement of the first connecting portion 561 and the second connecting portion 562 can affect the crystal direction oxidation rate, thereby affecting the oxidation range.

[0162] In some embodiments, the first connecting portion 561 and the second connecting portion 562 make it difficult for oxygen to enter the oxide layer 540, thereby affecting the oxidation rate of the corresponding oxide layer 540 and thus affecting the range of the oxidized area of ​​the oxide layer 540. This continues until a third oxidation arc 5413 is formed downwards from the first connecting portion 561 at the position corresponding to the oxide layer, and a fourth oxidation arc 5414 is formed downwards from the second connecting portion 562 at the position corresponding to the oxide layer, thereby forming an oxide hole 541 with a specific morphology. That is, the first connecting portion 561 and the second connecting portion 562, in conjunction with the anisotropy of the oxidation rate, further influence and balance the oxidation rate, thereby controlling the oxidation rate, ensuring the formation of the third oxidation arc 5413 and the fourth oxidation arc 5414, and thus ensuring the formation of the specific oxide hole 541.

[0163] In some embodiments, the third oxidation arc 5413 and the fourth oxidation arc 5414 have different radii of curvature, forming a specific irregular morphology. The oxide holes based on the irregular morphology can effectively suppress transverse multimode lasing of optical signals and reduce mode degeneracy.

[0164] In some embodiments, the oxidation rate varies in different directions, resulting in different oxidation regions at different locations. This leads to different inclination angles on each side of the oxidation pore, with the radius of curvature of the third oxidation arc 5413 being greater than that of the fourth oxidation arc 5414, thus forming an oxidation pore with a specific irregular morphology.

[0165] In some embodiments, during the formation of oxide holes with a specific morphology, the first connecting portion 561 and the second connecting portion 562 can be used as control variables for the formation of the specific morphology of the oxide holes. Combined with the crystal orientation oxidation rate, the width and narrow dimensions of the first connecting portion 561 and the second connecting portion 562 are controlled until the size of the first connecting portion 561 is larger than the size of the second connecting portion 562, thereby adjusting the morphology of the oxide holes.

[0166] In some embodiments, when the width of the first connecting portion 561 is greater than the width of the second connecting portion 562, a corresponding attachment is formed. Figure 12 The oxide pore morphology is shown. When the width of the first connecting portion 561 is smaller than the width of the second connecting portion 562, the opposite oxide pore morphology is formed.

[0167] like Figure 11 , Figure 12 As shown, the first trench portion 560 and the second trench portion 570 are in full contact with high-temperature water vapor, thereby causing oxygen inside the first trench portion 560 and the second trench portion 570 to move towards the oxide layer 540, thus oxidizing the oxide layer 540, forming a first oxide region 542. Since both sides of the second reflective layer 550 are also exposed, the second reflective layer 550 is also oxidized, forming a second oxide region 551.

[0168] In some embodiments, the first oxide region 542 includes aluminum oxide and arsenic oxide, and the second oxide region 551 includes aluminum oxide and arsenic oxide, then the first oxide region 542 and the second oxide region 551 are low refractive index insulating regions.

[0169] In some embodiments, the oxide aperture 541 is surrounded by a first oxide region 542. The oxide aperture 541 does not include aluminum oxide and arsenic oxide. The oxide aperture 541 is an unoxidized region with high refractive index and good conductivity. As a result, the light field is output along the oxide aperture, and the charge carriers are transported to the active region along the oxide aperture, thereby producing a high-efficiency photoelectric confinement effect.

[0170] In some embodiments, the first oxide region 542 is located between the first trench portion 560 and the second trench portion 570, and the second oxide region 551 is located between the first trench portion 560 and the second trench portion 570. The first trench portion 560 and the second trench portion 570 are disposed opposite to each other and are closed-looped by the first connecting portion 561 and the second connecting portion 562, so that the first oxide region 542 and the second oxide region 551 are annular regions composed of oxides.

[0171] In some embodiments, oxygen in the first trench portion 560 and the second trench portion 570 is oxidized inwards, forming a first oxidation region 542 in the oxide layer 540 and a second oxidation region 551 in the second reflective layer 550. Therefore, the outer contours of the first oxidation region 542 and the second oxidation region 551 are both formed along the first trench portion 560 and the second trench portion 570.

[0172] In some embodiments, both the oxide layer 540 and the second reflective layer 550 are AlGaAs. The molar content of Al components differs between the two. For example, the molar content of Al in the oxide layer 540 is greater than that in the second reflective layer 550. Therefore, the oxide layer 540 is oxidized at a higher rate and over a larger area, resulting in a longer inward extension of the first oxide region 542. Consequently, the pore size of the oxide holes 541 is smaller, which helps reduce pattern degeneracy.

[0173] In some embodiments, the inner contour line of the second oxide region 551 is further away from the oxide hole 541 than the inner contour line of the first oxide region 542. Therefore, the area occupied by the first oxide region 542 is larger than the area occupied by the second oxide region 551, and the pore size of the oxide hole 541 is smaller, which is beneficial to reduce pattern degeneracy.

[0174] In some embodiments, the oxygen filling the first trench portion 560 and the second trench portion 570 oxidizes inwards and outwards simultaneously, thereby forming a third oxide region 543 in the oxide layer 540 and a fourth oxide region 552 in the second reflective layer 550. Since the third oxide region 543 and the first oxide region 542 are formed simultaneously through oxidation, they are symmetrically arranged with respect to the area enclosed by the first trench portion 560 and the second trench portion 570. Similarly, the fourth oxide region 552 is symmetrically arranged with respect to the second oxide region 551.

[0175] In some embodiments, the second oxide region 551 and the fourth oxide region 552 are located on the side, which can further reduce the lateral diffusion of the light field and charge carriers, so that the light field and charge carriers converge and concentrate at the oxide hole 541.

[0176] Based on the laser chip provided in the above embodiments, this disclosure provides a method for fabricating a laser chip. Figure 13 This is a flowchart illustrating a method for fabricating a laser chip according to some embodiments. Figure 13 As shown. This disclosure provides a method for fabricating a laser chip, including:

[0177] S110: A first reflective layer, an active region, an oxide layer, and a second reflective layer are sequentially grown on the substrate surface, and the crystal plane index of the substrate surface is at a preset angle to the crystal plane.

[0178] In some embodiments, the second reflective layer 550 and the first reflective layer 520 inject P-type carriers and N-type carriers, respectively, into the active region 530. The P-type and N-type carriers recombine radiatively in the active region 530, releasing photons. These photons, in a specific oscillation mode, repeatedly feed back between the second reflective layer 550 and the first reflective layer 520, forming laser oscillations and generating a laser beam. A corresponding modulated optical signal is then generated by modulating an electrical signal. This optical signal is output along a direction perpendicular to the surface of the substrate 510, achieving vertical-cavity surface laser emission.

[0179] In some embodiments, a substrate 510 with a surface crystal plane index forming a predetermined angle with its {111} crystal plane is selected. A first reflective layer 520, an active region 530, an oxide layer 540, and a second reflective layer 550 are sequentially grown on the surface of the substrate 510. The substrate 510 with its surface crystal plane index forming a predetermined angle with its {111} crystal plane ensures that the layers above the substrate 510, such as the oxide layer 540 and the second reflective layer 550, also have surface crystal plane indices forming predetermined angles with their {111} crystal planes. Consequently, the crystal orientations of the oxide layer 540 and the second reflective layer 550 exhibit anisotropy. This anisotropy results in different atomic compositions, spatial structures, and interlayer distances for different crystal orientations, leading to varying degrees of bonding between the material and oxygen within the oxide layer 540.

[0180] S120: Etch downwards along the surface of the second reflective layer to above the active region to form a first trench and a second trench, thereby exposing the inner sidewalls of the oxide layer for oxidation etching. A first connecting portion connects one end of the second trench to one end of the first trench, and a second connecting portion connects the other end of the second trench to the other end of the first trench.

[0181] In some embodiments, to oxidize and etch the oxide layer 540 to form oxide holes 541 with a specific morphology, the laser chip 500 may include a first trench portion 560 and a second trench portion 570. The first trench portion 560 extends downward along the second reflective layer 550 above the active region 530, exposing one sidewall of the interior of the oxide layer 540. The second trench portion 570 extends downward along the second reflective layer 550 above the active region 530, exposing the other sidewall of the interior of the oxide layer 540.

[0182] In some embodiments, the first trench portion 560 and the second trench portion 570 are disposed opposite to each other. The first trench portion 560 and the second trench portion 570 may each be an arc-shaped trench portion to form an oxide hole 541 morphology. The two arc-shaped trench portions face the same center.

[0183] In some embodiments, the oxide layer 540 is oxidized and etched in a high-temperature water vapor environment. The first trench portion 560 and the second trench portion 570 are in full contact with the high-temperature water vapor. The high-temperature water vapor in the first trench portion 560 and the second trench portion 570 diffuses inward, thereby oxidizing the oxide layer 540 inward. At high temperature, the Al and As in the oxide layer 540 react with water, and the water is decomposed into oxygen by the high temperature, thereby oxidizing Al and As to form insulating oxides with low refractive index.

[0184] In some embodiments, to facilitate the formation of oxide holes 541 with a specific morphology, a first connecting portion 561 is connected between one end of the first trench portion 560 and one end of the second trench portion 570, and a second connecting portion 562 is connected between the other end of the first trench portion 560 and the other end of the second trench portion 570. That is, when etching is performed to form the first trench portion 560 and the second trench portion 570, the first connecting portion 561 and the second connecting portion 562 are not etched away, but are retained.

[0185] In some embodiments, photolithography is used to form the first trench portion 560 and the second trench portion 570. Photolithography is a process that uses the principle of photochemical reaction to transfer a pattern on a photomask onto a substrate. The pattern on the photomask includes the related patterns of the first trench portion 560 and the second trench portion 570.

[0186] In some embodiments, the photolithography process includes: uniform coating of photoresist, exposure, development, etching, etc. Photoresist refers to a thin film material whose solubility in the developing solution changes after exposure to light of a certain wavelength, resulting in a photochemical reaction in the exposed area. Photoresist is photochemically sensitive; after spin coating, pre-baking, exposure, and development, the pattern on the photomask is transferred to the substrate to obtain the desired circuit pattern. Based on the change in solubility before and after exposure, photoresist is classified into positive photoresist and negative photoresist. Positive photoresist, after exposure, has increased solubility in the developing solution and is dissolved, leaving the unexposed area as the desired pattern. Negative photoresist, after exposure, has decreased solubility in the developing solution and remains on the substrate; the unexposed area dissolves in the developing solution, and the resulting pattern is complementary to the pattern on the photomask.

[0187] S130: Placed in a high-temperature water vapor oxidation environment, oxygen in the first and second grooves contacts the oxide layer and oxidizes it inwards. The oxidized area forms the first oxidation zone, and the unoxidized area forms oxidation pores, which are surrounded by the first oxidation zone. The oxidation pores include a first oxidation arc, a second oxidation arc, a third oxidation arc, and a fourth oxidation arc. The first and second oxidation arcs are positioned opposite each other, as are the third and fourth oxidation arcs, and the third and fourth oxidation arcs have different radii of curvature.

[0188] In some embodiments, the first trench portion 560 and the second trench portion 570 are in full contact with high-temperature water vapor, thereby allowing oxygen inside the first trench portion 560 and the second trench portion 570 to move towards the oxide layer 540, thereby oxidizing the oxide layer 540, forming a first oxide region 542 in the oxidized area. Oxidation pores 541 are formed in the unoxidized area.

[0189] In some embodiments, the anisotropic crystal orientation of the oxide layer 540 results in different atomic compositions, spatial structures, and interlayer distances, leading to varying degrees of bonding between the material and oxygen within the oxide layer. Consequently, the oxidation rate differs along different directions when oxidizing inwards from the first trench 560 and the second trench 570, resulting in different oxidation rates and thus different oxidized areas. Simultaneously, the positions of the first connecting portion 561 and the second connecting portion 562 make it difficult for oxygen to enter the oxide layer, thereby affecting the oxidation rate of the corresponding oxide layer 540 and consequently the oxidized area of ​​the oxide layer 540. The influence of crystal orientation anisotropy on the oxidation rate, and the mutual coordination of the first connecting portion 561 and the second connecting portion 562 on the oxidation rate, allows for the formation of oxide holes 541 with specific morphologies. This effectively suppresses transverse multimode laser lasing and reduces mode degeneracy.

[0190] In some embodiments, the oxidation rate is controlled by the anisotropy of the crystal orientation and the cooperation of the first connection portion 561 and the second connection portion 562, thereby controlling the morphology of the oxide hole 541, forming an irregular morphology, effectively suppressing laser transverse multimode lasing, and reducing mode degeneracy.

[0191] In some embodiments, the formed oxide hole 541 includes a first oxide arc 5411, a second oxide arc 5412, a third oxide arc 5413, and a fourth oxide arc 5414. The first oxide arc 5411 and the second oxide arc 5412 are disposed opposite to each other, and the third oxide arc 5413 and the fourth oxide arc 5414 are disposed opposite to each other. The first oxide arc 5411 faces the first trench portion 560, and the second oxide arc 5412 faces the second trench portion 570. The third oxide arc 5413 is disposed facing the first connecting portion 561, and the fourth oxide arc 5414 is disposed facing the second connecting portion 562.

[0192] In some embodiments, the third oxidation arc 5413 and the fourth oxidation arc 5414 have different radii of curvature, forming a specific irregular morphology. The oxide holes based on the irregular morphology can effectively suppress transverse multimode lasing of optical signals and reduce mode degeneracy.

[0193] As mentioned earlier, the laser chip 500 can be packaged as a 1×N array chip to achieve multi-channel transmission.

[0194] Figure 14This is a schematic diagram of a laser chip array emitting light according to some embodiments. For example... Figure 14 As shown, in some embodiments, the laser chip 500 is a 1×4 array packaged chip, which emits four optical signals to achieve four-channel transmission. Exemplarily, these four optical signals have the same wavelength.

[0195] The following example uses the laser chip 500 as a 1×2 array packaged chip for illustrative purposes.

[0196] Figure 15 This is a cross-sectional view of another laser chip structure according to some embodiments. Figure 16 This is a partial top view of another laser chip structure according to some embodiments. Figure 15 and Figure 16 As shown, in some embodiments, the laser chip 500 emits a first optical signal and a second optical signal to achieve array light emission.

[0197] In some embodiments, the laser chip 500 may include a substrate 510a. Its features can be referenced to the substrate 510.

[0198] In some embodiments, the laser chip 500 may include a first reflective layer 520a. The first reflective layer 520a is located above the substrate 510a. The first reflective layer 520a may be an N-type distributed Bragg reflector (N-DBR) layer.

[0199] In some embodiments, the laser chip 500 may include an active region 530a. The active region 530a is located above the first reflective layer 520a.

[0200] In some embodiments, the laser chip 500 may include an oxide layer 540a. The oxide layer 540a is located above the active region 530a. The oxide layer 540a includes a first oxide hole 541a and a second oxide hole 541b.

[0201] In some embodiments, the laser chip 500 may include a second reflective layer 550a. The second reflective layer 550a is located above the oxide layer 540a. The second reflective layer 550a may be a P-type Distributed Bragg Reflection (P-DBR) layer.

[0202] In some embodiments, the first reflective layer 520a provides N-type carriers to the active region 530a, and the second reflective layer 550a provides P-type carriers to the active region 530a. N-type and P-type carriers recombine in the active region 530a to generate photons. The second reflective layer 550a and the first reflective layer 520a form a resonant cavity, allowing photons to oscillate within the cavity to generate laser light, and a corresponding modulated optical signal is generated by modulating an electrical signal.

[0203] In some embodiments, based on the high refractive index and conductivity of the oxide aperture, a portion of the P-type carriers flow through the first oxide aperture 541a and are injected into the active region 530a, corresponding to the generation of a first optical signal. A portion of the P-type carriers flow through the second oxide aperture 541b and are injected into the active region 530a, corresponding to the generation of a second optical signal. The first and second optical signals have the same wavelength.

[0204] In some embodiments, a first optical signal is output from a first oxide hole 541a along a path perpendicular to the surface of the substrate 510a, and a second optical signal is output from a second oxide hole 541b along a path perpendicular to the surface of the substrate 510a, thereby achieving array light emission.

[0205] In some embodiments, the first oxide aperture 541a and the oxide aperture 541 have the same morphological features. Furthermore, the first oxide aperture 541a includes a first oxide arc 5411a, a second oxide arc 5412a, a third oxide arc 5413a, and a fourth oxide arc 5414a. The third oxide arc 5413a and the fourth oxide arc 5414a have different radii of curvature, forming an irregular morphology, which effectively suppresses the transverse multimode lasing of the first optical signal and reduces mode degeneracy.

[0206] In some embodiments, the second oxide aperture 541b has the same morphological characteristics as the oxide aperture 541. Furthermore, the second oxide aperture 541b includes a fifth oxide arc 5411b, a sixth oxide arc 5412b, a seventh oxide arc 5413b, and an eighth oxide arc 5414b. The seventh oxide arc 5413b and the eighth oxide arc 5414b have different radii of curvature, forming an irregular morphology, which effectively suppresses transverse multimode lasing of the second optical signal and reduces mode degeneracy.

[0207] In some embodiments, during the array chip packaging process, its long side is susceptible to stress due to the expansion / contraction deformation of the circuit board at different temperatures. Under different temperature conditions, the quantum well gain of the active region 530a changes under external stress, leading to an increase in laser lasing modes and affecting parameters such as extinction ratio and output power. To address this, the long axis of the first oxide hole 541a is aligned parallel to the long side extension direction of the substrate 510a, and the long axis of the second oxide hole 541b is aligned parallel to the long side extension direction of the substrate 510a, thereby improving the stress application direction. Thus, when the device cools down, the compressive strain from the long side has a gain-enhancing effect on the quantum well material in the active region, reducing the impact of stress on the transverse multimode of the device, and thus helping to balance the optical power and number of modes at low temperatures.

[0208] In some embodiments, since the first oxide pore 541a has the same morphological characteristics as the oxide pore 541, similarly, the second oxide pore 541b has the same morphological characteristics as the oxide pore 541. Therefore, the first oxide pore 541a and the second oxide pore 541b have the same formation conditions as the oxide pore 541.

[0209] In some embodiments, the surface crystal index of the substrate 510a is at a predetermined angle to its {111} crystal plane, so that the surface crystal index of the oxide layer 540a and the second reflective layer 550a is at a predetermined angle to its {111} crystal plane, thereby utilizing the influence of their crystal orientation anisotropy on the oxidation rate.

[0210] In some embodiments, etching is performed downwards along the surface of the second reflective layer 550a to above the active region 530a to form a first trench portion 571 and a second trench portion 572, thereby exposing the inner sidewalls of the oxide layer 540a for oxidation etching. A first connecting portion 561a is connected between one end of the first trench portion 571 and one end of the second trench portion 572, and a second connecting portion 562a is connected between the other end of the first trench portion 571 and the other end of the second trench portion 572.

[0211] In some embodiments, etching is performed downwards along the surface of the second reflective layer 550a to above the active region 530a to form a third trench portion 573 and a fourth trench portion 574, thereby exposing the inner sidewalls of the oxide layer 540a for oxidation etching. To form a second oxide hole 541b with a specific morphology, a third connecting portion 561b is connected between one end of the third trench portion 573 and one end of the fourth trench portion 574, and a fourth connecting portion 562b is connected between the other end of the third trench portion 573 and the other end of the fourth trench portion 574.

[0212] In some embodiments, anisotropy leads to differences in atomic composition, spatial structure, and interlayer distances in different crystal orientations, resulting in varying degrees of bonding between the material inside the oxide layer 540a and oxygen. Consequently, during oxidation from the first trench portion 571 and the second trench portion 572 inwards, the oxidation rates differ along different directions, leading to different oxidation rates and thus different oxidized areas within the oxide layer 540a. Simultaneously, the positions of the first connecting portion 561a and the second connecting portion 562a make it difficult for oxygen to enter the oxide layer 540a, thereby affecting the oxidation rate of the corresponding oxide layer and consequently the oxidized area of ​​the oxide layer 540a. By controlling the effect of crystal orientation anisotropy on the oxidation rate and the mutual coordination of the first connecting portion 561a and the second connecting portion 562a on the oxidation rate, the oxidation rate is controlled, thereby controlling the formation of the first oxide hole 541a with a specific morphology. The formation process of the second oxide hole 541b is similar and will not be described in detail further.

[0213] In some embodiments, the oxide layer 540a is oxidized by oxygen in the first trench portion 571 and the second trench portion 572 to form a first oxide region 542a, and the unoxidized region forms a first oxide hole 541a. The first oxide hole 541a is surrounded by the first oxide region 542a. The first oxide region 542a is oxidized to form a low refractive index, insulating oxide, while the first oxide hole 541a is not oxidized. Therefore, the refractive index of the first oxide hole 541a is greater than that of the first oxide region 542a, and the conductivity of the first oxide hole 541a is greater than that of the first oxide region 542a, thereby producing a high-efficiency photoelectric confinement effect. The second oxide hole 541b is similarly treated. The oxide layer 540a is oxidized by oxygen in the third trench portion 573 and the fourth trench portion 574 to form a fifth oxide region 542b, and the unoxidized region forms a second oxide hole 541b. The second oxide hole 541b is surrounded by the fifth oxide region 542b.

[0214] In some embodiments, the first oxide hole 541a includes a third oxide arc 5413a and a fourth oxide arc 5414a. The third oxide arc 5413a is disposed toward the first connecting portion 561a, and the fourth oxide arc 5414a is disposed toward the second connecting portion 562a. The first oxide arc 5411a is disposed toward the first trench portion 571, and the second oxide arc 5412a is disposed toward the second trench portion 572.

[0215] In some embodiments, the first connecting portion 561a is larger than the second connecting portion 562a. The radius of curvature of the third oxidation arc 5413a is larger than the radius of curvature of the fourth oxidation arc 5414a.

[0216] In some embodiments, the second oxide hole 541b includes a seventh oxide arc 5413b and an eighth oxide arc 5414b. The seventh oxide arc 5413b is disposed toward the third connecting portion 561b, and the eighth oxide arc 5414b is disposed toward the fourth connecting portion 562b. The fifth oxide arc 5411b is disposed toward the third trench portion 573, and the sixth oxide arc 5412b is disposed toward the fourth trench portion 574.

[0217] In some embodiments, the size of the third connecting portion 561b is larger than the size of the fourth connecting portion 562b. The radius of curvature of the seventh oxidation arc 5413b is larger than the radius of curvature of the eighth oxidation arc 5414b.

[0218] In some embodiments, other technical features of the laser chip 500 when it is a 1×N array package can be referred to when the laser chip is a 1×1 type, and will not be elaborated further.

[0219] Figure 17 This is a diagram of the internal structure of another laser chip according to some embodiments. Figure 17 As shown, in some embodiments, the long axis of the first oxide hole 541a is parallel to the long side extension direction of the substrate 510a, and the long axis of the second oxide hole 541b is parallel to the long side extension direction of the substrate 510a, thereby improving the stress application direction. Thus, when the device cools, the compressive strain from the long side will have a gain-enhancing effect on the active region quantum well material, reducing the impact of stress on the transverse multimode of the device, thereby helping to balance the optical power and the number of modes at low temperatures.

[0220] Based on the laser chip provided in the above embodiments, this disclosure provides a method for fabricating a laser chip. Figure 18 This is a flowchart illustrating another method for fabricating a laser chip according to some embodiments. Figure 18 As shown. This disclosure provides a method for fabricating a laser chip, including:

[0221] S210: A first reflective layer, an active region, an oxide layer, and a second reflective layer are sequentially grown on the substrate surface, and the crystal plane index of the substrate surface is at a preset angle to the crystal plane.

[0222] In some embodiments, the steps are the same as S110, so they will not be described in detail here.

[0223] S220: Etch downwards along the surface of the second reflective layer to above the active region to form the first trench portion, the second trench portion, the third trench portion, and the fourth trench portion, so that the inner sidewalls of the oxide layer are exposed to the outside, thereby oxidizing and etching the oxide layer.

[0224] In some embodiments, a first trench portion 571, a second trench portion 572, a third trench portion 573, and a fourth trench portion 574 are simultaneously etched using a photomask.

[0225] In some embodiments, a first connecting portion 561a is connected between one end of the second groove portion 572 and one end of the first groove portion 571. A second connecting portion 562a is connected between the other end of the second groove portion 572 and the other end of the first groove portion 571.

[0226] A third connecting portion 561b is connected between one end of the fourth groove portion 574 and one end of the third groove portion 573. A fourth connecting portion 562b is connected between the other end of the fourth groove portion 574 and the other end of the third groove portion 573.

[0227] In some embodiments, the first connecting portion 561a and the second connecting portion 562a can cooperate with the anisotropy of the crystal orientation to affect the oxidation rate, thereby controlling the oxidation rate and thus controlling the morphology of the first oxide hole 541a. Similarly, the third connecting portion 561b and the fourth connecting portion 562b can cooperate to form the morphology of the second oxide hole 541b.

[0228] S230: Placed in a high-temperature steam oxidation system, oxygen in the first and second trenches contacts the oxide layer and oxidizes it inwards, forming a first oxidation zone in the oxidized area and a first oxidation pore in the unoxidized area. The first oxidation pore is surrounded by the first oxidation zone. Oxygen in the third and fourth trenches contacts the oxide layer and oxidizes it inwards, forming a fifth oxidation zone in the oxidized area and a second oxidation pore in the unoxidized area. The second oxidation pore is surrounded by the fifth oxidation zone.

[0229] In some embodiments, the first oxide hole 541a and the second oxide hole 541b respectively exhibit irregular morphologies, thereby effectively suppressing the transverse multimode lasing of the first optical signal and the second optical signal and reducing mode degeneracy.

[0230] In some embodiments, the long axis of the first oxide hole 541a is arranged parallel to the long side extension direction of the substrate 510a, and the long axis of the second oxide hole 541b is arranged parallel to the long side extension direction of the substrate 510a, thereby improving the stress application direction. Thus, when the device cools down, the compressive strain from the long side will have a gain-enhancing effect on the quantum well material in the active region, reducing the impact of stress on the transverse multimode of the device, thereby helping to balance the optical power and the number of modes at low temperatures.

[0231] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A laser chip, characterized by include: The substrate has a surface crystal plane index at a predetermined angle to the crystal plane; A first reflective layer is located above the substrate; An active region, located above the first reflective layer, is configured such that N-type carriers and P-type carriers recombine in the active region to generate photons; the first reflective layer provides the N-type carriers to the active region; An oxide layer is located above the active region. The oxide layer includes oxide holes, which are surrounded by a first oxide region. The oxide holes include a first oxidation arc, a second oxidation arc, a third oxidation arc, and a fourth oxidation arc. The first oxidation arc and the second oxidation arc are arranged opposite to each other, and the third oxidation arc and the fourth oxidation arc are arranged opposite to each other. The radii of curvature of the third oxidation arc and the fourth oxidation arc are different. The second reflective layer, located above the oxide layer, is configured to provide P-type charge carriers to the active region, which flow into the active region along the oxide aperture; the second reflective layer and the first reflective layer form a resonant cavity, in which photons oscillate to generate laser light, and a corresponding modulated optical signal is generated by modulating an electrical signal, which is output from the oxide aperture in a direction perpendicular to the substrate surface. The first trench extends downward along the surface of the second reflective layer to above the active region, and the first trench is located on one side of the first oxide region; The second trench extends downward along the surface of the second reflective layer to above the active region, and the second trench is located on the other side of the first oxide region; a first connecting portion is connected between one end of the second trench and one end of the first trench, and a second connecting portion is connected between the other end of the second trench and the other end of the first trench.

2. The laser chip of claim 1, wherein, The refractive index of the oxide hole is greater than that of the first oxide region, and the conductivity of the oxide hole is greater than that of the first oxide region. The first oxidation arc faces the first trench portion, and the second oxidation arc faces the second trench portion; The third oxidation arc is disposed toward the first connecting portion, and the fourth oxidation arc is disposed toward the second connecting portion; the size of the first connecting portion is larger than the size of the second connecting portion. The radius of curvature of the third oxidation arc is greater than that of the fourth oxidation arc.

3. The laser chip of claim 1, wherein, The first trench portion and the second trench portion are configured to expose the inner sidewalls of the oxide layer to perform oxidation etching on the oxide layer to form the first oxide region; at the same time, the second reflective layer is oxidized to generate the second oxide region; The first oxide region includes aluminum oxide and arsenic oxide, the second oxide region includes aluminum oxide and arsenic oxide, and the oxide pores do not include aluminum oxide or arsenic oxide.

4. The laser chip of claim 3, wherein, The first oxidation zone is located between the first trench portion and the second trench portion, and the second oxidation zone is located between the first trench portion and the second trench portion; The inner contour line of the second oxide region is further away from the oxide hole than the inner contour line of the first oxide region; The outer contours of the first oxidation zone and the second oxidation zone are both formed by the first groove portion and the second groove portion.

5. The laser chip of claim 3, wherein, The oxide layer includes a third oxide region, and the second reflective layer includes a fourth oxide region; The third oxidation zone is symmetrically arranged relative to the first oxidation zone, and the area enclosed by the first trench portion and the second trench portion is symmetrically arranged. The fourth oxidation zone is symmetrically arranged relative to the second oxidation zone, and the area enclosed by the first groove portion and the second groove portion is symmetrically arranged.

6. The laser chip of claim 1, wherein, If the crystal plane index of the substrate surface forms a 15° angle with its {111} crystal plane, then the crystal plane index of the oxide layer and the second reflective layer forms a 15° angle with their {111} crystal planes.

7. The laser chip of claim 1, wherein, The oxide layer and the second reflective layer each comprise AlGaAs, and the molar content of Al in the oxide layer is greater than the molar content of Al in the second reflective layer.

8. A method of fabricating a laser chip, characterized by, The preparation method includes: A first reflective layer, an active region, an oxide layer, and a second reflective layer are sequentially grown on the substrate surface, and the crystal plane index of the substrate surface is at a preset angle to the crystal plane. The second reflective layer is etched downwards along its surface to above the active region to form a first trench and a second trench, thereby exposing the inner sidewalls of the oxide layer for oxidation etching. A first connection is provided between one end of the second trench and one end of the first trench, and a second connection is provided between the other end of the second trench and the other end of the first trench. When placed in a high-temperature water vapor oxidation environment, oxygen in the first and second grooves contacts the oxide layer and oxidizes it inward. The oxidized area forms a first oxidation zone, and the unoxidized area forms an oxidation pore. The oxidation pore is surrounded by the first oxidation zone. The oxidation pore includes a first oxidation arc, a second oxidation arc, a third oxidation arc, and a fourth oxidation arc. The first oxidation arc and the second oxidation arc are arranged opposite each other, and the third oxidation arc and the fourth oxidation arc are arranged opposite each other. The radii of curvature of the third oxidation arc and the fourth oxidation arc are different.

9. The method of claim 8, wherein the laser chip is prepared by a method comprising: The refractive index of the oxide hole is greater than that of the first oxide region, and the conductivity of the oxide hole is greater than that of the first oxide region. The first oxidation arc faces the first trench portion, and the second oxidation arc faces the second trench portion; The third oxidation arc is disposed toward the first connecting portion, and the fourth oxidation arc is disposed toward the second connecting portion; the size of the first connecting portion is larger than the size of the second connecting portion. The radius of curvature of the third oxidation arc is greater than that of the fourth oxidation arc.

10. The method of claim 8, wherein the laser chip is prepared by a method comprising: The oxygen in the first and second trenches comes into contact with the second reflective layer and oxidizes the second reflective layer to form a second oxidation zone.

11. The method of claim 10, wherein the laser chip is prepared by a method comprising: The first oxidation zone is located on the inner side between the first trench portion and the second trench portion; The second oxidation zone is located on the inner side between the first trench portion and the second trench portion; The inner contour line of the second oxide region is further away from the oxide hole than the inner contour line of the first oxide region; The outer contours of the first oxidation zone and the second oxidation zone are both formed by the first groove portion and the second groove portion.

12. The method of claim 10, wherein the laser chip is prepared by a method comprising: The oxide layer includes a third oxide region, and the second reflective layer includes a fourth oxide region; The third oxidation zone is symmetrically arranged relative to the first oxidation zone, and the area enclosed by the first trench portion and the second trench portion is symmetrically arranged. The fourth oxidation zone is symmetrically arranged relative to the second oxidation zone, and the area enclosed by the first groove portion and the second groove portion is symmetrically arranged.

13. The method of claim 8, wherein the laser chip is prepared by a method comprising: The oxide layer and the second reflective layer each comprise AlGaAs, and the molar content of Al in the oxide layer is greater than the molar content of Al in the second reflective layer.

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