Semiconductor laser chip epitaxial devices and lasers

Abstract

The present invention relates to the field of semiconductor laser technology, and in particular to semiconductor laser chip epitaxial devices and lasers. The semiconductor laser chip epitaxial device comprises: an intermediate layer; a first cladding and a second cladding respectively located on opposite sides of the intermediate layer and stacked with the intermediate layer; wherein the intermediate layer comprises a quantum well layer; the second cladding comprises a first sub-cladding, a second sub-cladding and a third sub-cladding arranged in sequence along the stacking direction of the first cladding, the intermediate layer and the second cladding; the refractive index of the first sub-cladding is less than the refractive index of the third sub-cladding, and both belong to the refractive index range of the second sub-cladding in which the refractive index changes continuously or in steps. Based on this, the present invention can effectively reduce the influence of the material composition deviation caused by the growth process on the laser characteristics, and ensure low-loss single-mode output of the laser in the vertical direction.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor laser technology, in particular to a semiconductor laser chip epitaxial device and a laser. Background Art

[0002] Semiconductor laser materials are usually grown on corresponding substrate materials such as GaAs (gallium arsenide) or InP (indium phosphide) according to pre-designed structures using methods such as molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD). Figure 1 As shown, a typical semiconductor epitaxial structure includes an n-side cladding layer, an undoped active region, and a p-side cladding layer, wherein the active region includes a quantum well and a waveguide layer.

[0003] Currently, semiconductor lasers have two failure modes: 1) catastrophic optical damage (COD) and 2) catastrophic optical mirror damage (COMD). Most device failures are caused by COD, which is caused by: 1) the destruction of the laser lattice leads to the appearance of a large number of non-radiative recombination centers on the surface. These centers undergo non-radiative recombination during laser operation, generating a large amount of heat. This accumulation of heat causes device failure; 2) for semiconductor laser devices containing aluminum, the aluminum exposed to the atmosphere is easily oxidized after the cavity surface cleaves in the atmosphere, introducing more cavity surface defects; 3) the laser cavity surface needs to be plated with other materials to change the light emissivity at the cavity surface. Because the thermal expansion coefficient and other material properties of the plated material differ significantly from those of the semiconductor material, this can cause failure during laser operation.

[0004] Based on this, in order to increase the threshold power / current of COMD, a large optical cavity (LOC) design is often adopted in the design to reduce the power density and increase the spot size.

[0005] However, during long-term research and practice on existing technologies, the inventors discovered that, in order for the high-order modes supported by the LOC waveguide to be coupled to the n-side cladding and substrate as leaky modes, the refractive indices of the waveguide and n-side cladding must be relatively close. This results in poor growth stability of the epitaxial structure and a very small growth window. If the n-side cladding refractive index is less than the designed value, the high-order modes cannot be coupled to the substrate and are instead converted into guided modes. If the n-side cladding refractive index is greater than the designed value, the optical field of the fundamental mode becomes significantly larger and is coupled to the substrate, resulting in unnecessary losses. Summary of the Invention

[0006] Based on the problems and shortcomings of the above-mentioned prior art, the present invention provides a semiconductor laser chip epitaxial device and a laser, which can reduce the impact of material composition deviation caused by the growth process on the laser characteristics and ensure low-loss single-mode output of the laser in the vertical direction.

[0007] One embodiment of the present application provides a semiconductor laser chip epitaxial device, including:

[0008] middle layer;

[0009] A first cladding layer and a second cladding layer are respectively located on opposite sides of the intermediate layer and stacked with the intermediate layer; wherein,

[0010] The intermediate layer includes a quantum well layer;

[0011] The second cladding layer comprises a first sub-cladding layer, a second sub-cladding layer and a third sub-cladding layer sequentially arranged along a stacking direction of the first cladding layer, the intermediate layer and the second cladding layer;

[0012] The refractive index of the first subcladding is smaller than that of the third subcladding, the refractive index of the second subcladding changes continuously or in steps, and the maximum refractive index of the second subcladding is greater than that of the third subcladding.

[0013] Optionally, at the connection between the first subcladding and the second subcladding, the refractive index of the first subcladding is equal to the refractive index of the second subcladding; at the connection between the second subcladding and the third subcladding, the refractive index of the second subcladding is greater than the refractive index of the third subcladding.

[0014] Optionally, the refractive index of the second sub-cladding changes continuously, and the refractive index of the second sub-cladding gradually increases along the stacking direction.

[0015] Optionally, the refractive index of the second sub-cladding changes in a broken line; wherein the refractive index of the second sub-cladding at any inflection point is greater than the refractive index of the first sub-cladding and less than the refractive index of the third sub-cladding.

[0016] Optionally, the refractive index of the first cladding is smaller than the refractive index of the first sub-cladding.

[0017] Optionally, the thickness of the first waveguide layer is smaller than the thickness of the second waveguide layer, and the thickness of the first sub-cladding is smaller than the thickness of the third sub-cladding.

[0018] Optionally, the intermediate layer further includes a first waveguide layer and a second waveguide layer, which are respectively located on opposite sides of the quantum well layer and stacked with the quantum well layer.

[0019] Optionally, the first waveguide layer is a p-side waveguide layer, the second waveguide layer is an n-side waveguide layer, the first cladding layer is a p-side cladding layer, and the second cladding layer is an n-side cladding layer; or

[0020] The first waveguide layer is an n-side waveguide layer, the second waveguide layer is a p-side waveguide layer, the first cladding layer is an n-side cladding layer, and the second cladding layer is a p-side cladding layer.

[0021] Optionally, the semiconductor laser chip epitaxial device further includes a substrate layer;

[0022] The second cladding layer, the intermediate layer and the first cladding layer are stacked in sequence on the substrate layer, and the second cladding layer is adjacent to the substrate layer.

[0023] Based on the same inventive concept, an embodiment of the present application further provides a laser, including the above-mentioned semiconductor laser chip epitaxial device.

[0024] One of the above technical solutions has the following advantages and beneficial effects:

[0025] The present application provides a semiconductor laser chip epitaxial device and laser. By adding a second sub-cladding with a continuously or step-wise refractive index between the first sub-cladding and the third sub-cladding, the effect of material composition deviations caused by the growth process on the laser characteristics is reduced, thereby ensuring low-loss single-mode output of the laser in the vertical direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present application will describe the embodiments in conjunction with the accompanying drawings. The drawings in this application are only used to describe the embodiments and for the purpose of illustration.

[0027] Figure 1 It is a schematic structural diagram of a typical semiconductor quantum well laser epitaxial device in the prior art;

[0028] Figure 2 Schematic diagram of the refractive index distribution of each layer of a typical LOC structure in the prior art and the confinement of the fundamental mode and high-order modes in the confinement layer;

[0029] Figure 3Schematic diagram of the refractive index distribution of each layer of the asymmetric LOC structure in the prior art and the confinement of the fundamental mode and the high-order mode in the confinement layer;

[0030] Figure 4 Schematic diagram of the refractive index distribution of each layer of the asymmetric LOC structure in the prior art;

[0031] Figure 5 Schematic diagram of the situation where the fundamental mode light field is confined in the confinement layer when a growth error (-0.01) occurs in the X(Al) of the n-side cladding layer of the asymmetric LOC structure in the prior art;

[0032] Figure 6 A schematic diagram illustrating the situation in which the light field of a high-order mode is confined in the confinement layer when a growth error (+0.01) occurs in the X(Al) of the n-side cladding layer of an asymmetric LOC structure in the prior art provided in one embodiment of the present application;

[0033] Figure 7 A schematic structural diagram of a semiconductor laser chip epitaxial device provided in one embodiment of the present application;

[0034] Figure 8 A schematic structural diagram of a semiconductor laser chip epitaxial device provided in one embodiment of the present application;

[0035] Figure 9 A schematic diagram of the refractive index distribution of each layer of an asymmetric LOC structure provided in one embodiment of the present application;

[0036] Figure 10 Based on Figure 9 Schematic diagram of the situation where the fundamental mode light field is confined in the confinement layer when a growth error (-0.01) occurs in the X(Al) of the n-side cladding;

[0037] Figure 11 Based on Figure 9 Schematic diagram of the situation where the high-order mode light field is confined in the confinement layer when there is a growth error (+0.01) in the X(Al) of the n-side cladding;

[0038] Figure 12 A schematic diagram of the refractive index distribution of each layer of an asymmetric LOC structure provided in one embodiment of the present application;

[0039] Figure 13 Based on Figure 12 Schematic diagram of the situation where the fundamental mode light field is confined in the confinement layer when a growth error (-0.01) occurs in the X(Al) of the n-side cladding;

[0040] Figure 14 A schematic diagram of the refractive index distribution of each layer of an asymmetric LOC structure provided in one embodiment of the present application;

[0041] Figure 15 Based on Figure 14 Schematic diagram of the situation where the high-order mode light field is confined in the confinement layer when there is a growth error (+0.01) in the X(Al) of the n-side cladding;

[0042] Figure 16 A schematic diagram of the refractive index distribution of each layer of an asymmetric LOC structure provided in one embodiment of the present application;

[0043] Figure 17 Based on Figure 16 Schematic diagram of the situation where the high-order mode light field is confined in the confinement layer when there is a growth error (+0.01) in the X(Al) of the n-side cladding;

[0044] Figure 18 A schematic diagram of the refractive index distribution of each layer of an asymmetric LOC structure provided in one embodiment of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0046] The terms "first," "second," and the like in this application are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0047] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0048] like Figure 1 As shown, Figure 1This is a schematic diagram of the structure of a typical semiconductor quantum well laser epitaxial device. Starting from the substrate, a typical semiconductor epitaxial device consists of an n-side cladding layer, an undoped n-side waveguide layer, a quantum well, an undoped p-side waveguide layer, and a p-side cladding layer. Semiconductor lasers typically use AlGaAs, AlGaInP, or AlGaInAs as the materials for the cladding and waveguide layers. The refractive index of these materials is negatively correlated with the Al elemental composition, X(Al). The Al elemental composition, X(Al), of the waveguide material is lower than that of the cladding material, resulting in a higher refractive index, forming a refractive index waveguide.

[0049] like Figure 2 As shown in Figure 1, in a typical LOC structure, the n-side cladding layer serves as a confinement layer with a refractive index of n = 3.22. The fundamental mode (m = 0 mode) has an effective refractive index of n = 3.39, and the higher-order mode (m = 1 mode) has an effective refractive index of n = 3.37. Experimental results show that both the fundamental and higher-order modes are confined to the waveguide layer, becoming guided modes.

[0050] like Figure 3 As shown, in an asymmetric LOC structure, the n-side cladding layer serves as a confinement layer with a refractive index of n = 3.376. The fundamental mode (m = 0 mode) has an effective refractive index of n = 3.39, and the higher-order mode (m = 1 mode) has an effective refractive index of n = 3.37. The experimental results show that the fundamental mode is confined in the waveguide layer and becomes a guided mode, while the higher-order modes are confined in the confinement layer and the substrate layer and become leaky modes.

[0051] Therefore, in order for a semiconductor laser chip epitaxial device to confine the fundamental mode to the waveguide layer and the higher-order modes to the confinement layer and substrate layer during operation, the refractive index of the confinement layer must be smaller than the effective refractive index of the fundamental mode to confine the fundamental mode's light field. The larger the difference between the two, the better the confinement effect. The opposite is true for higher-order modes; the refractive index of the confinement layer must be larger than the effective refractive index of the higher-order modes.

[0052] In practical designs, the refractive index of the waveguide layer and the cladding layer must be close. When the waveguide layer thickness is greater than 1 μm, the difference in Al composition between the two layers must be around 0.02-0.03 to ensure that the effective refractive index of the high-order mode (m=1 mode) is lower than that of the cladding. This will reduce the growth stability of the epitaxial structure and narrow the growth window.

[0053] like Figure 4 As shown, in the existing asymmetric LOC design, the n-side cladding includes the first cladding with the lowest refractive index and the second cladding with a refractive index slightly lower than that of the waveguide layer. Figure 5 As shown in , if the refractive index of the n-side cladding is less than the designed value, the high-order mode cannot be coupled to the substrate, but is converted into a guided mode. There is a situation where the two guided modes compete with each other, making the laser unable to work normally; Figure 6As shown in the figure, if the refractive index of the n-side cladding is greater than the design value, the difference between the refractive index of the n-side cladding and the effective refractive index of the fundamental mode becomes smaller, and the confinement effect on the fundamental mode becomes worse, causing more light fields to enter the high-loss confinement layer and may even be coupled to the substrate layer, causing unnecessary losses.

[0054] For example, when the aluminum component in the n-side cladding material changes by 0.01, the resulting change in refractive index may have a significant impact on the distribution of the actual light field (the distribution pattern of Ey along the vertical direction), causing the performance of the grown material to differ significantly from the designed performance, so that the device performance cannot meet specific requirements.

[0055] In view of this, if Figure 7 As shown, one embodiment of the present invention provides a semiconductor laser chip epitaxial device, comprising:

[0056] Middle layer 10;

[0057] A first cladding layer 20 and a second cladding layer 30 are respectively located on opposite sides of the intermediate layer 10 and stacked with the intermediate layer 10; wherein the intermediate layer 10 includes a quantum well layer 11; the second cladding layer 30 includes a first subcladding layer 31, a second subcladding layer 32, and a third subcladding layer 33 arranged in sequence along the stacking direction of the first cladding layer 20, the intermediate layer 10, and the second cladding layer 30;

[0058] The refractive index of the first subcladding 31 is smaller than that of the third subcladding 33 , the refractive index of the second subcladding 32 changes continuously or in steps, and the maximum refractive index of the second subcladding 32 is greater than that of the third subcladding 33 .

[0059] Among them, such as Figure 8 As shown, the intermediate layer 10 further includes a first waveguide layer 12 and a second waveguide layer 13 which are respectively located on opposite sides of the quantum well layer and stacked with the quantum well layer.

[0060] Exemplarily, the first waveguide layer 12 is a p-side waveguide layer, the second waveguide layer 13 is an n-side waveguide layer, the first cladding layer 20 is a p-side cladding layer, and the second cladding layer 30 is an n-side cladding layer. Alternatively, the first waveguide layer 12 is an n-side waveguide layer, the second waveguide layer 13 is a p-side waveguide layer, the first cladding layer 20 is an n-side cladding layer, and the second cladding layer 30 is a p-side cladding layer.

[0061] The semiconductor laser chip epitaxial device further includes a substrate layer 40 ; the second cladding layer 30 , the intermediate layer 10 and the first cladding layer 20 are sequentially stacked on the substrate layer 40 , and the second cladding layer is adjacent to the substrate layer 40 .

[0062] Illustratively, the above embodiment adopts an asymmetric LOC structure design, then the refractive index of the first cladding 20 is smaller than the refractive index of the first sub-cladding 31, the thickness of the first waveguide layer 12 is smaller than the thickness of the second waveguide layer 13, and the thickness of the first sub-cladding 31 is smaller than the thickness of the third sub-cladding 33.

[0063] In the above embodiment, the second sub-cladding 32 having a continuously or step-wise changing refractive index is added between the first sub-cladding 31 and the third sub-cladding 33 of the second cladding 30 (e.g., the n-side cladding) of the semiconductor laser chip epitaxial device, and the maximum refractive index of the second sub-cladding 32 is greater than the refractive index of the third sub-cladding 33. This allows the fundamental mode of the semiconductor laser chip epitaxial device to be confined to the waveguide layer and the higher-order modes to be confined to the second cladding 30 and the substrate layer 40 during operation, thereby achieving low-loss single-mode output of the laser in the vertical direction and reducing the impact of material composition deviation caused by the growth process on laser characteristics.

[0064] Furthermore, to ensure that the fundamental mode is effectively confined to the waveguide layer and higher-order modes are effectively confined to the second cladding layer 30 and substrate layer 40, the refractive index of the confinement layer must be less than the effective refractive index of the fundamental mode to achieve a confining effect on the fundamental mode's light field. The greater the difference between the two, the better the confinement effect. For higher-order modes, the refractive index of the confinement layer must be greater than the effective refractive index of the higher-order modes. Therefore, at the junction of the first subcladding 31 and the second subcladding 32, the refractive index of the first subcladding 31 is equal to that of the second subcladding 32; and at the junction of the second subcladding 32 and the third subcladding 33, the refractive index of the second subcladding 32 is greater than that of the third subcladding 33.

[0065] In one embodiment, the refractive index of the second sub-cladding 32 changes continuously, and the refractive index of the second sub-cladding 32 gradually increases along the stacking direction, so that in the second sub-cladding 32, the refractive index of a portion is smaller than the effective refractive index of the fundamental mode, and the refractive index of another portion is greater than the effective refractive index of the higher-order mode.

[0066] Furthermore, the refractive index of the second sub-cladding 32 changes in a broken line, wherein the refractive index of the second sub-cladding 32 at any inflection point is greater than the refractive index of the first sub-cladding 31 and less than the refractive index of the third sub-cladding 33 .

[0067] like Figure 9 As shown, between the first sub-cladding 31 and the third sub-cladding 33, by changing the X (Al) of the cladding material, the second sub-cladding 32 with a changed refractive index is added as a high-order mode coupling layer.

[0068] It can be understood that the refractive index of the second subcladding 32 varies in a convex broken line. The second subcladding 32 consists of sections 1-3: the refractive index at node 1 is the same as that of the first subcladding 31; the refractive index at node 2 is greater than that of the first subcladding 31 and less than that of the second subcladding 32; and the refractive index at node 3 is greater than that of the third subcladding 33 and greater than that of the waveguide layer.

[0069] Since the refractive index of the 1-2 portion of the second sub-cladding 32 is lower than that of the third sub-cladding 33, the difference between the effective refractive index of the fundamental mode and the higher-order mode and the refractive index of the 1-2 portion is greater. In this portion, the light fields of the fundamental mode and the higher-order mode are confined, that is, the light fields are attenuated. Among them, because the effective refractive index of the fundamental mode is larger, the light field of the fundamental mode is attenuated faster in the 1-2 portion. At the inflection point 2, the light field of the fundamental mode is attenuated to the smallest possible extent. Therefore, the fundamental mode is less restricted in the 2-3 portion than the higher-order mode, and the higher-order mode is more easily coupled to the third sub-cladding 33 and the substrate layer 40 in the 2-3 portion due to its higher refractive index.

[0070] Taking the epitaxial device design of a 905nm laser as an example, the quantum well is InGaAs and the waveguide layer is AlGaAs. The X(Al) of each part is as follows:

[0071] X(Al) thickness Point 1 0.5 / 1-2 thickness / 0.2um Point 2 0.4 / 2-3 thickness / 0.8um Point 3 0.24 / Point 4 0.32 / Point 5 0.3 /

[0072] When the growth error (e.g. ±0.01) of X(Al) in the n-side cladding occurs, Figure 10-11 As shown, the fundamental mode can still be confined in the waveguide layer to become a guided mode, while the high-order mode can be confined in the second cladding layer 30 and the substrate layer 40 to become a leaky mode, and the influence of the deviation of the growth process on the laser characteristics is reduced.

[0073] For example, Figure 9 The standard scheme is shown, such as Figure 12 In the modified scheme shown, Figure 9 The inflection point 2 shown is designed to be closer to the first sub-cladding 31 in the vertical direction, that is, the thickness of the 1-2 portion is close to 0, or is 0. Figure 13 As shown in the figure, when the growth error of X(Al) in the n-side cladding layer occurs (such as ±0.01), the limiting effect of the 1-2 part on the fundamental mode light field becomes worse. Figure 9 In the design shown, the fundamental mode is more affected, making the optical field of the fundamental mode larger in the n-side cladding, thereby increasing the absorption loss.

[0074] For example, Figure 9 The standard scheme is shown, such as Figure 14In the modified solution shown, the change in the refractive index of the second sub-cladding 32 is not a convex broken line, but a straight line directly from the first sub-cladding 31 to the third sub-cladding 33. Figure 15 As shown, since the refractive index of the 1-2 part is smaller than that of the standard solution (such as Figure 9 As shown in Figure 2, the high-order mode light field converges faster in the vertical direction. Due to the decrease in refractive index, the waveguide's restriction of the high-order mode light field is strengthened. When the growth error of X(Al) in the n-side cladding occurs (such as ±0.01), the high-order mode is not as effective as when coupled to the confinement layer. Figure 9 The design of the convex fold line shown is good.

[0075] For example, Figure 9 The standard scheme is shown, such as Figure 16 In the modified scheme shown, Figure 9 The refractive index at the inflection point 3 is designed to be equal to the refractive index of the third sub-cladding 33. Figure 17 As shown, the high-order modes cannot be coupled to the confinement layer and instead become guided modes.

[0076] For example, Figure 9 The standard scheme is shown, such as Figure 18 In the modified solution shown, to prevent the fundamental mode from coupling to the confinement layer, the thickness of the first subcladding 31 needs to be increased, so that the intensity of the fundamental mode light field at the high refractive index (the second subcladding 32) is not too high, and the thickness of the second subcladding 32 cannot be too thick. However, both of these modifications reduce the effect of coupling higher-order modes to the confinement layer.

[0077] As described above, the refractive index of the second subcladding 32 follows a convex broken line, with the inflection point not vertically close to either the first subcladding 31 or the third subcladding 33. Furthermore, the maximum refractive index of the second subcladding 32 is greater than that of the third subcladding 33, and the refractive index of the second subcladding 32 at any inflection point is greater than that of the first subcladding 31 and less than that of the third subcladding 33. Based on this, the fundamental mode light field can be more rapidly attenuated in the 1-2 section without being affected by the refractive indices of the 2-3 section and the confinement layer. The high refractive index of the 2-3 section allows the light field of higher-order modes to be more coupled into the confinement layer.

[0078] Similarly, if the refractive index distribution of the second sub-cladding 32 is a convex curve, the above technical effect can also be achieved.

[0079] Based on the same inventive concept, an embodiment of the present application further provides a laser, including the above-mentioned semiconductor laser chip epitaxial device.

[0080] The above is only a preferred embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A semiconductor laser chip epitaxial device, characterized in that: include: middle layer; A first cladding layer and a second cladding layer are respectively located on opposite sides of the intermediate layer and stacked with the intermediate layer; wherein, The intermediate layer includes a quantum well layer; The second cladding layer comprises a first sub-cladding layer, a second sub-cladding layer and a third sub-cladding layer sequentially arranged along a stacking direction of the first cladding layer, the intermediate layer and the second cladding layer; The semiconductor laser chip epitaxial device further includes: substrate layer; The second cladding layer, the intermediate layer and the first cladding layer are stacked in sequence on the substrate layer, and the second cladding layer is adjacent to the substrate layer; The refractive index of the first sub-cladding is smaller than the refractive index of the third sub-cladding, the refractive index of the second sub-cladding changes continuously, and the maximum refractive index of the second sub-cladding is greater than the refractive index of the third sub-cladding; When the refractive index of the second sub-cladding changes continuously, the refractive index of the second sub-cladding gradually increases along the stacking direction.

2. The semiconductor laser chip epitaxial device according to claim 1, characterized in that: At the connection between the first subcladding and the second subcladding, the refractive index of the first subcladding is equal to the refractive index of the second subcladding; at the connection between the second subcladding and the third subcladding, the refractive index of the second subcladding is greater than the refractive index of the third subcladding.

3. The semiconductor laser chip epitaxial device according to claim 1, characterized in that: The refractive index of the second sub-cladding changes in a broken line, wherein the refractive index of the second sub-cladding at any inflection point is greater than the refractive index of the first sub-cladding and less than the refractive index of the third sub-cladding.

4. The semiconductor laser chip epitaxial device according to claim 1, characterized in that: The refractive index of the first cladding is smaller than the refractive index of the first sub-cladding.

5. The semiconductor laser chip epitaxial device according to any one of claims 1 to 4, characterized in that: The intermediate layer further includes a first waveguide layer and a second waveguide layer respectively located on opposite sides of the quantum well layer and stacked with the quantum well layer. The first waveguide layer and the first cladding layer are adjacently arranged.

6. The semiconductor laser chip epitaxial device according to claim 5, characterized in that: The thickness of the first waveguide layer is smaller than that of the second waveguide layer, and the thickness of the first sub-cladding is smaller than that of the third sub-cladding.

7. The semiconductor laser chip epitaxial device according to claim 6, characterized in that: The first waveguide layer is a p-side waveguide layer, the second waveguide layer is an n-side waveguide layer, the first cladding layer is a p-side cladding layer, and the second cladding layer is an n-side cladding layer; or The first waveguide layer is an n-side waveguide layer, the second waveguide layer is a p-side waveguide layer, the first cladding layer is an n-side cladding layer, and the second cladding layer is a p-side cladding layer.

8. A laser, characterized in that: The device comprises a semiconductor laser chip epitaxial device as claimed in any one of claims 1 to 7.

Images