Laser, optical transmitter and optical module
By introducing AlN material into the active layer of the laser and optimizing the quantum barrier layer components, the problem of low modulation bandwidth of GaN-based lasers is solved, and higher electron injection and constraints are achieved, and the rate characteristics of the light source are improved.
Patent Information
- Application Number
- CN202310693727.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-12
- Publication Date
- 2024-12-13
AI Technical Summary
The modulation bandwidth of GaN-based lasers is low and cannot meet the higher requirements of the light source rate characteristics. It is mainly due to the piezoelectric polarization effect of GaN-based materials that cause the overlap of electron hole wave functions in the quantum well to decrease, radiation recombination and differential gain deterioration. .
The AlN low-lattice constant material is introduced into the active layer of the laser. By optimizing the proportion of material components of the lower quantum barrier layer and the upper quantum barrier layer, the quantum well lattice matching is achieved and the piezoelectricity caused by lattice mismatch is reduced Polarization increases the modulation bandwidth of the laser and improves electron injection and binding.
It significantly improves the modulation bandwidth of the laser, improves electron injection and constraints, reduces low-frequency roll-off, and improves eye diagram characteristics and drive efficiency.
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Figure CN119134045A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of lasers, and in particular to a laser, an optical transmitter and an optical module. Background Art
[0002] With the development of optical networking, various application scenarios of visible light communication have put forward new requirements for the rate characteristics of light sources. In terms of visible light communication light sources, there are two main technical routes: laser diodes (LD) and light-emitting diodes (LED). LD light sources have longer transmission distances and higher rates than LEDs, and the modulation bandwidth of LD is around 1GHz. LEDs have a larger field of view than LDs, and the modulation bandwidth of LEDs generally does not exceed 500MHz.
[0003] For current GaN-based lasers, the piezoelectric polarization effect of GaN-based materials leads to a reduction in the overlap of electron-hole wave functions in quantum wells, and the degradation of radiative recombination and differential gain, resulting in a low modulation bandwidth of GaN-based lasers. Therefore, in order to meet higher requirements for the speed characteristics of light sources, a laser with a higher modulation bandwidth is urgently needed. Summary of the invention
[0004] The embodiments of the present application provide a laser, an optical transmitter and an optical module, which improve the modulation bandwidth of the laser and achieve better electron injection and electron confinement.
[0005] In a first aspect, an embodiment of the present application provides a laser. The laser includes: a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, an upper confinement layer and an electrical contact layer. Among them, the lower confinement layer is located above the substrate, the lower waveguide layer is located above the lower confinement layer, the active layer is located above the lower waveguide layer, the upper waveguide layer is located above the active layer, the electron blocking layer is located above the upper waveguide layer, the upper confinement layer is located above the electron blocking layer, and the electrical contact layer is located above the upper confinement layer. Specifically, the active layer includes a lower quantum barrier layer, a middle quantum barrier layer and an upper quantum barrier layer. The middle quantum barrier layer is located above the lower quantum barrier layer, and the upper quantum barrier layer is located above the middle quantum barrier layer. The materials used in each quantum barrier layer in the active layer include aluminum (Al), indium (In), gallium (Ga) and nitrogen (N). The component proportion of In in the lower quantum barrier layer is greater than the component proportion of In in the lower waveguide layer, and the component proportion of In in the upper quantum barrier layer is greater than the component proportion of In in the upper waveguide layer.
[0006] In this embodiment, AlN, a material with a low lattice constant, is introduced into each quantum barrier layer in the active layer of the laser, which can achieve lattice matching with the quantum well while ensuring the limiting effect of the quantum barrier layer, minimize the strong piezoelectric polarization caused by lattice mismatch, reduce the energy band tilt of the quantum well, achieve polarization matching of each quantum barrier layer, and improve the modulation bandwidth of the laser. In addition, the component ratio of In in the lower quantum barrier layer is greater than the component ratio of In in the lower waveguide layer, and the component ratio of In in the upper quantum barrier layer is greater than the component ratio of In in the upper waveguide layer, which is conducive to obtaining better electron injection and electron confinement.
[0007] In some possible implementations, in each quantum barrier layer of the active layer, the component ratio of Ga is greater than that of In, and the component ratio of Ga is greater than that of Al, which is more conducive to achieving polarization matching of each quantum barrier layer.
[0008] In some possible implementations, the Al content in the lower quantum barrier layer is less than that in the upper quantum barrier layer, and the Al content in the upper quantum barrier layer is less than that in the middle quantum barrier layer, so that the low-frequency roll-off of the laser is lower, which is beneficial to the eye diagram characteristics.
[0009] In some possible implementations, the In component ratio in the upper quantum barrier layer is less than that in the lower quantum barrier layer, and the In component ratio in the lower quantum barrier layer is less than that in the middle quantum barrier layer, so that the low-frequency roll-off of the laser is lower, which is beneficial to the eye diagram characteristics.
[0010] In some possible implementations, the component ratios of each material in the lower quantum barrier layer, the component ratios of each material in the middle quantum barrier layer, and the component ratios of each material in the upper quantum barrier layer are the same, which is more conducive to improving the modulation bandwidth of the laser.
[0011] In some possible implementations, in each quantum barrier layer of the active layer, the composition ratio of In is greater than the composition ratio of Al.
[0012] In some possible implementations, the materials used for the lower waveguide layer include Al, In, Ga and N, and the materials used for the upper waveguide layer include Al, In, Ga and N, which is beneficial to improving the modulation bandwidth of the laser.
[0013] In some possible embodiments, the difference between the composition ratio of In in the three materials of Al, In and Ga in the lower quantum barrier layer and the composition ratio of In in the three materials of Al, In and Ga in the lower waveguide layer is greater than or equal to 9% and less than or equal to 20%, which is conducive to obtaining better electron injection.
[0014] In some possible embodiments, the difference between the composition ratio of In in the upper quantum barrier layer among the three materials of Al, In and Ga and the composition ratio of In in the upper waveguide layer among the three materials of Al, In and Ga is greater than or equal to 0% and less than or equal to 14%, which is conducive to obtaining better electron confinement.
[0015] In some possible implementations, in the lower quantum barrier layer, the component ratio of Al in the three materials of Al, In and Ga is greater than or equal to 8% and less than or equal to 15%. In the upper quantum barrier layer, the component ratio of Al in the three materials of Al, In and Ga is greater than or equal to 10% and less than or equal to 18%. In the middle quantum barrier layer, the component ratio of Al in the three materials of Al, In and Ga is greater than or equal to 15% and less than or equal to 25%. By designing the component ratio of Al in each quantum barrier layer, it is beneficial to better achieve polarization matching of each quantum barrier layer and improve the modulation bandwidth of the laser.
[0016] In some possible implementations, the active layer further includes a first quantum well layer and a second quantum well layer. The first quantum well layer is located between the lower quantum barrier layer and the middle quantum barrier layer, and the second quantum well layer is located between the middle quantum barrier layer and the upper quantum barrier layer. The materials used in the first quantum well layer include In, Ga, and N, and the materials used in the second quantum well layer include In, Ga, and N.
[0017] In some possible implementations, in the first quantum well layer, the In component ratio of the two materials In and Ga is greater than or equal to 10% and less than or equal to 35%. In the second quantum well layer, the In component ratio of the two materials In and Ga is greater than or equal to 10% and less than or equal to 35%.
[0018] In a second aspect, an embodiment of the present application provides an optical transmitter. The optical transmitter includes a driver and a laser as described in any implementation of the first aspect. The driver is used to drive the laser to emit light.
[0019] In a third aspect, an embodiment of the present application provides an optical module, which includes an optical receiver and an optical transmitter as described in the second aspect.
[0020] In this embodiment, AlN, a material with a low lattice constant, is introduced into each quantum barrier layer in the active layer of the laser, which can achieve lattice matching with the quantum well while ensuring the limiting effect of the quantum barrier layer, minimize the strong piezoelectric polarization caused by lattice mismatch, reduce the energy band tilt of the quantum well, achieve polarization matching of each quantum barrier layer, and improve the modulation bandwidth of the laser. In addition, the component ratio of In in the lower quantum barrier layer is greater than the component ratio of In in the lower waveguide layer, and the component ratio of In in the upper quantum barrier layer is greater than the component ratio of In in the upper waveguide layer, which is conducive to obtaining better electron injection and electron confinement. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 A schematic diagram of an optical communication system used in an embodiment of the present application;
[0022] Figure 2 This is a schematic diagram of the structure of a laser in an embodiment of the present application;
[0023] Figure 3 A schematic diagram of the structure of the active layer of the laser in the embodiment of the present application;
[0024] Figure 4 Another structural schematic diagram of the active layer of the laser in the embodiment of the present application;
[0025] Figure 5 Schematic diagram of the energy band of a quantum barrier layer with conventional design;
[0026] Figure 6 The energy band diagram for three quantum barrier layers with the same component ratio;
[0027] Figure 7 Schematic diagram of energy bands with differentiated component ratios for three quantum barrier layers;
[0028] Figure 8 A schematic diagram showing the comparison of modulation bandwidths of lasers with different designs;
[0029] Fig. 9 Schematic diagram for comparing PI characteristics of lasers with different designs;
[0030] Fig.10 This is a schematic diagram of the structure of an optical transmitter in an embodiment of the present application;
[0031] Fig.11 This is a schematic diagram of the structure of an optical module in an embodiment of the present application. DETAILED DESCRIPTION
[0032] The embodiments of the present application provide a laser, an optical transmitter and an optical module, which improve the modulation bandwidth of the laser and achieve better electron injection and electron confinement.
[0033] It should be noted that the terms "first" and "second" in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, rather than to limit a specific order or precedence. It should be understood that the above terms can be interchanged where appropriate, so that the embodiments described in this application can be implemented in an order other than the content described in this application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0034] It should be understood that if an element or layer is referred to as being "on" another element or layer, it can be directly on the other element or layer, or there may be an intermediate element or layer. In order to facilitate the description of the relationship between an element shown in the figure and another element, spatial relationship terms may be used here, such as "under...", "below...", "below", "above...", "on", etc. It should be understood that spatial relationship terms are intended to include different orientations of devices in application or operation in addition to the directions described in the drawings. For example, if the device in the drawings is flipped, the element described as "under other elements or features" or "under other elements or features" will be oriented to "above other elements or features". In this way, terms such as "under..." may include both above and below orientations. The device may be oriented otherwise (rotated 90 degrees or in other directions), and the spatial descriptors here are also understood accordingly.
[0035] Figure 1 A schematic diagram of an optical communication system used in an embodiment of the present application. The optical transmitting end includes components such as a laser, a driver, and a digital to analog converter (DAC), and the optical receiving end includes components such as a photodiode (PD), a trans-impedance amplifier (TIA), and an analog to digital converter (ADC). The optical transmitting end modulates the laser generated by the laser to obtain an optical signal carrying business information, and transmits the optical signal to the optical receiving end through an optical fiber. The optical receiving end converts the received optical signal into an electrical signal to obtain business information.
[0036] It should be noted that the embodiment of the present application provides a laser, in which AlN, a material with a low lattice constant, is introduced into each quantum barrier layer in the laser active layer, and the component ratio of the material in each quantum barrier is designed. The modulation bandwidth of the laser is improved, and better electron injection and electron confinement are achieved. The laser provided by the present application is described in detail below.
[0037] Figure 2 FIG. 1 is a schematic diagram of the structure of a laser in an embodiment of the present application. Figure 2 As shown, the laser includes but is not limited to a substrate 1, a lower confinement layer 2, a lower waveguide layer 3, an active layer 4, an upper waveguide layer 5, an electron blocking layer 6, an upper confinement layer 7, and an electrical contact layer 8. Among them, the lower confinement layer 2 is above the substrate 1, the lower waveguide layer 3 is above the lower confinement layer 2, the active layer 4 is above the lower waveguide layer 3, the upper waveguide layer 5 is above the active layer 4, the electron blocking layer 6 is above the upper waveguide layer 5, the upper confinement layer 7 is above the electron blocking layer 6, and the electrical contact layer 8 is above the upper confinement layer 7. It should be noted that the lower confinement layer 2 and the upper confinement layer 7 are used to limit carriers and photons in the vertical direction. The active layer 4 is used to provide optical gain. The electron blocking layer 6 is used to block electrons overflowing from the active layer 4. The electrical contact layer 8 specifically includes a P-type electrode, and an N-type electrode is also provided below the substrate 1. It should be understood that the active layer 4 includes multiple quantum barrier layers and multiple quantum well layers, and the quantum barrier layers and the quantum well layers are alternately distributed. The active layer 4 is introduced in detail below.
[0038] Figure 3 FIG. 1 is a schematic diagram of the structure of the active layer of the laser in the embodiment of the present application. Figure 3 As shown, the active layer 4 includes, from bottom to top, a lower quantum barrier layer 10, a first quantum well layer 40, a middle quantum barrier layer 20, a second quantum well layer 50 and an upper quantum barrier layer 30. It should be understood that the number of the middle quantum barrier layer 20 can be one layer or multiple layers. Figure 3 The illustrated medium quantum barrier layer 20 is a one-layer embodiment. Figure 4 An implementation method in which the medium quantum barrier layer 20 is a multi-layer structure is provided.
[0039] Figure 4 FIG. 2 is another schematic diagram of the structure of the active layer of the laser in the embodiment of the present application. Figure 4 As shown, the active layer 4 specifically includes a medium quantum barrier layer 1, a medium quantum barrier layer 2, and a medium quantum barrier layer 3, and there is also a quantum well layer between every two medium quantum barrier layers. For example, the medium quantum barrier layer 1 includes a quantum well layer 1 between the medium quantum barrier layer 1 and the medium quantum barrier layer 2, and the medium quantum barrier layer 2 includes a quantum well layer 2 between the medium quantum barrier layer 2 and the medium quantum barrier layer 3.
[0040] It should be noted that the materials used in each quantum barrier layer in the lower quantum barrier layer 10, the middle quantum barrier layer 20 and the upper quantum barrier layer 30 include aluminum (Al), indium (In), gallium (Ga) and nitrogen (N). Since AlN, a material with a low lattice constant, is introduced into each quantum barrier layer, it is possible to achieve lattice matching with the quantum well while ensuring the limiting effect of the quantum barrier layer, minimize the strong piezoelectric polarization caused by lattice mismatch, reduce the energy band tilt of the quantum well, achieve polarization matching of each quantum barrier layer, and improve the modulation bandwidth of the laser. Further, in each quantum barrier layer, the component ratio of Ga is greater than the component ratio of In, and the component ratio of Ga is greater than the component ratio of Al. It should be understood that the materials used in each quantum well layer in the active layer include In, Ga and N.
[0041] It should also be noted that the present application does not limit the specific material composition of the lower waveguide layer 3 and the upper waveguide layer 5. For example, the material used in the lower waveguide layer 3 includes In, Ga and N, or the material used in the lower waveguide layer 3 includes Al, In, Ga and N. For another example, the material used in the upper waveguide layer 5 includes In, Ga and N, or the material used in the upper waveguide layer 5 includes Al, In, Ga and N.
[0042] Since the lower waveguide layer 3 is a material with a large lattice constant and a large band order, and there is a large polarization effect between the lower quantum barrier layer 10 and the lower waveguide layer 3, resulting in a higher potential barrier, which is not only not conducive to polarization matching, but also hinders electron injection. Similarly, the band order between the upper waveguide layer 5 and the upper quantum barrier layer 30 is large, and there is also a large polarization effect, which leads to the appearance of capture traps for electrons at the interface between the upper quantum barrier layer 30 and the upper waveguide layer 5, which is not only not conducive to polarization matching, but also increases the probability of electrons escaping from the active layer. Therefore, the present application considers increasing the component proportion of In in the lower quantum barrier layer 10 and the upper quantum barrier layer 30, which is conducive to obtaining better electron injection and electron confinement. Specifically, the component proportion of In in the lower quantum barrier layer 10 is greater than the component proportion of In in the lower waveguide layer 3, and the component proportion of In in the upper quantum barrier layer 30 is greater than the component proportion of In in the upper waveguide layer 5.
[0043] It should be understood that the present application is mainly designed for the composition ratio of the three materials Al, In and Ga in each quantum barrier layer. For the convenience of description, the following will use the subscript values corresponding to the materials to represent the composition ratio of the three materials. In other words, the sum of the subscript values corresponding to the three materials is 1. For example, the material used in a quantum barrier layer is Al 0.1 In 0.2 Ga 0.7N means that in the quantum barrier layer, the composition of Al in the three materials of Al, In and Ga accounts for 10%, the composition of In in the three materials of Al, In and Ga accounts for 20%, and the composition of Ga in the three materials of Al, In and Ga accounts for 70%.
[0044] In a possible implementation, the three quantum barrier layers in the active layer use the same composition ratio. Optionally, in each quantum barrier layer, the composition ratio of In is greater than the composition ratio of Al. As an example, the three quantum barrier layers in the active layer all use Al. 0.15 In 0.18 Ga 0.67 N material.
[0045] In another possible implementation, the three quantum barrier layers in the active layer use differentiated component ratios. That is, the component ratios used in the lower quantum barrier layer 10, the component ratios used in the middle quantum barrier layer 20, and the component ratios used in the upper quantum barrier layer 30 are different. Specifically, the component ratio of Al in the lower quantum barrier layer 10 is less than the component ratio of Al in the upper quantum barrier layer 30, and the component ratio of Al in the upper quantum barrier layer is less than the component ratio of Al in the middle quantum barrier layer. The component ratio of In in the upper quantum barrier layer is less than the component ratio of In in the lower quantum barrier layer, and the component ratio of In in the lower quantum barrier layer is less than the component ratio of In in the middle quantum barrier layer. As an example, the material used in the lower quantum barrier layer 10 is Al 0.10 In 0.15 Ga 0.75 N, the material used for the quantum barrier layer 20 is Al 0.24 In 0.24 Ga 0.52 N, the material used for the upper quantum barrier layer 30 is Al 0.15 In 0.10 Ga 0.75 N.
[0046] The following is an introduction to the difference in the effects of quantum barrier layers with different designs, combined with the energy band diagrams of quantum barrier layers with different designs. It should be understood that Figure 5-Figure 7 The vertical axis shown represents energy. Figure 5-Figure 7 The horizontal axis shown in FIG. 1 represents the position of each layer structure in the active layer. The horizontal axis represents the position of each layer structure arranged from bottom to top in the active layer from left to right. For example, Figure 5-Figure 7 The three relatively raised parts in the graph correspond to the three quantum barrier layers in the active layer. Figure 5-Figure 7 The two relatively concave parts in the middle correspond to the two quantum well layers in the active layer.
[0047] Figure 5Schematic diagram of the energy band of a conventionally designed quantum barrier layer. The materials used in the conventionally designed quantum barrier layer include In, Ga and N, but not Al. It should be understood that the GaN, InN and AlN materials epitaxially grown using Metal-Organic Chemical Vapor Deposition (MOCVD) under conventional conditions belong to the hexagonal wurtzite structure. Due to the lack of a symmetry center in the c-axis direction, the positive and negative charge centers do not coincide, and the material exhibits a strong polarization effect. There are two types of polarization effects, one is spontaneous polarization and the other is piezoelectric polarization. For spontaneous polarization, when the GaN-based material grows along the (0001) direction, the material is a Ga surface, the spontaneous polarization direction is (000-1), and the polarization electric field direction is (0001). As for piezoelectric polarization, when InGaN material is epitaxially grown, since the lattice constant of InN is much larger than that of GaN, the strong compressive stress causes a strong polarization electric field to be generated in InGaN. The direction of this electric field is opposite to the direction of the spontaneous polarization electric field and points to (000-1). Due to the large lattice mismatch, for quantum barrier layers using conventional InGaN design, the polarization electric field is mainly dominated by the piezoelectric polarization electric field, resulting in the appearance of energy bands such as Figure 5 The obvious tilt shown in the figure will seriously deteriorate the overlap integral of electrons and holes, reduce the recombination matrix elements, lead to a longer recombination lifetime, and affect the high-frequency modulation performance.
[0048] Figure 6 The energy band diagram of the three quantum barrier layers with the same composition ratio. Specifically, the three quantum barrier layers are all made of Al 0.15 In 0.18 Ga 0.67 N material as an example, it can be seen that Figure 6 The energy bands shown are compared to Figure 5 However, this component design will lead to a larger polarization effect between the lower quantum barrier layer and the lower waveguide layer, resulting in a higher potential barrier, such as Figure 6 In addition, this component design will also make the band gap between the upper waveguide layer and the upper quantum barrier layer larger, and there will also be a large polarization effect, resulting in the capture trap of electrons at the interface between the upper quantum barrier layer and the upper waveguide layer, such as Figure 6 Shown in the dotted circle.
[0049] Figure 7 Schematic diagram of energy bands with different component ratios in three quantum barrier layers. Specifically, the material used in the lower quantum barrier layer 10 is Al 0.10 In 0.15 Ga 0.75 N, the material used for the quantum barrier layer 20 is Al 0.24 In 0.24 Ga0.52 N, the material used for the upper quantum barrier layer 30 is Al 0.15 In 0.10 Ga 0.75 N. By Figure 7 and Figure 6 It can be seen from the comparison that the lower quantum barrier layer 10 reduces the composition ratio of Al to In and reduces the barrier height. The upper quantum barrier layer 30 increases the composition ratio of Al to In and increases the barrier height. Figure 7 In the illustrated embodiment, each quantum barrier layer can achieve better electron injection and electron confinement while achieving polarization matching.
[0050] Figure 8 Figure 2 is a schematic diagram comparing the modulation bandwidth of lasers with different designs. Figure 8 As shown, the abscissa represents frequency (GHz) and the ordinate represents frequency response (dB). Figure 8 The modulation bandwidth of three lasers with different designs is shown. The first is a conventional laser design, i.e. Figure 5 The second is a laser with no difference in the composition ratio of the three quantum barrier layers, that is, Figure 6 The third type is a laser with different composition ratios of the three quantum barrier layers, namely Figure 7 The design method introduced. By comparison, it can be seen that the modulation bandwidth of the second and third lasers is significantly increased compared to the first laser. The maximum modulation bandwidth of the third laser is slightly lower than that of the second laser, but the damping is smaller at the same current and the low-frequency roll-off is lower, which is beneficial to the eye diagram characteristics.
[0051] Fig. 9 Figure 1 is a schematic diagram comparing the PI characteristics of lasers with different designs. Fig. 9 As shown, the abscissa represents current (mA) and the ordinate represents power (mW). Fig. 9 The PI characteristics of lasers with three different designs are shown. The first is a conventional laser design, i.e. Figure 5 The second is a laser with no difference in the composition ratio of the three quantum barrier layers, that is, Figure 6 The third type is a laser with different composition ratios of the three quantum barrier layers, namely Figure 7 By comparison, it can be seen that compared with the first laser, the driving current threshold of the second and third lasers is greatly reduced, the driving efficiency is greatly increased, and the maximum output optical power is also greatly increased.
[0052] Some specific examples are provided below to further introduce the component design of each layer structure in the active layer.
[0053] Example 1: In the lower quantum barrier layer 10, the composition ratio of Al in the three materials of Al, In and Ga is greater than or equal to 8% and less than or equal to 15%. The difference between the composition ratio of In in the three materials of Al, In and Ga in the lower quantum barrier layer 10 and the composition ratio of In in the three materials of Al, In and Ga in the lower waveguide layer 3 is greater than or equal to 9% and less than or equal to 20%.
[0054] Example 2: In the upper quantum barrier layer 30, the composition ratio of Al in the three materials of Al, In and Ga is greater than or equal to 10% and less than or equal to 18%. The difference between the composition ratio of In in the three materials of Al, In and Ga in the upper quantum barrier layer 30 and the composition ratio of In in the three materials of Al, In and Ga in the upper waveguide layer 5 is greater than or equal to 0% and less than or equal to 14%.
[0055] Example 3: In the medium quantum barrier layer 20, the composition ratio of Al in the three materials of Al, In and Ga is greater than or equal to 15% and less than or equal to 25%.
[0056] Example 4: In the first quantum well layer 40, the composition ratio of In in the two materials In and Ga is greater than or equal to 10% and less than or equal to 35%. In the second quantum well layer 50, the composition ratio of In in the two materials In and Ga is greater than or equal to 10% and less than or equal to 35%.
[0057] From the above introduction, it can be seen that the present application introduces AlN, a low lattice constant material, into each quantum barrier layer in the laser active layer, which can achieve lattice matching with the quantum well while ensuring the limiting effect of the quantum barrier layer, minimize the strong piezoelectric polarization caused by lattice mismatch, reduce the energy band tilt of the quantum well, achieve polarization matching of each quantum barrier layer, and improve the modulation bandwidth of the laser. In addition, the component ratio of In in the lower quantum barrier layer is greater than the component ratio of In in the lower waveguide layer, and the component ratio of In in the upper quantum barrier layer is greater than the component ratio of In in the upper waveguide layer, which is conducive to obtaining better electron injection and electron confinement.
[0058] The laser provided in the present application is introduced above, and the optical transmitter and optical module provided in the present application are introduced below.
[0059] Fig.10 FIG. 1 is a schematic diagram of the structure of an optical transmitter in an embodiment of the present application. Fig.10 As shown, the optical transmitter includes a driver 101 and a laser 102. The laser 102 may be any of the lasers described in the above embodiments. The driver 101 is used to drive the laser 102 to emit light.
[0060] Fig.11Schematic diagram of the structure of an optical module in the embodiment of the present application. Fig.11 As shown, the optical module includes an optical transmitter 201 and an optical receiver 202. The optical transmitter 201 is used for light transmission, and the optical receiver 202 is used for light reception. Fig.10 The illustrated embodiment introduces an optical transmitter.
[0061] Finally, it should be noted that the above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A laser, characterized in that: include: a substrate, a lower confinement layer located above the substrate, a lower waveguide layer located above the lower confinement layer, an active layer located above the lower waveguide layer, an upper waveguide layer located above the active layer, an electron blocking layer located above the upper waveguide layer, an upper confinement layer located above the electron blocking layer, and an electrical contact layer located above the upper confinement layer; The active layer includes a lower quantum barrier layer, a middle quantum barrier layer located above the lower quantum barrier layer, and an upper quantum barrier layer located above the middle quantum barrier layer. The material used in each quantum barrier layer in the active layer includes aluminum Al, indium In, gallium Ga, and nitrogen N. The component proportion of In in the lower quantum barrier layer is greater than the component proportion of In in the lower waveguide layer, and the component proportion of In in the upper quantum barrier layer is greater than the component proportion of In in the upper waveguide layer.
2. The laser according to claim 1, characterized in that In each quantum barrier layer of the active layer, the component ratio of Ga is greater than the component ratio of In, and the component ratio of Ga is greater than the component ratio of Al.
3. The laser according to claim 1 or 2, characterized in that: The Al component ratio in the lower quantum barrier layer is smaller than the Al component ratio in the upper quantum barrier layer, and the Al component ratio in the upper quantum barrier layer is smaller than the Al component ratio in the middle quantum barrier layer.
4. The laser according to any one of claims 1 to 3, characterized in that The In component ratio in the upper quantum barrier layer is smaller than the In component ratio in the lower quantum barrier layer, and the In component ratio in the lower quantum barrier layer is smaller than the In component ratio in the middle quantum barrier layer.
5. The laser according to claim 1 or 2, characterized in that: The component ratio of each material in the lower quantum barrier layer, the component ratio of each material in the middle quantum barrier layer and the component ratio of each material in the upper quantum barrier layer are the same.
6. The laser according to claim 5, characterized in that In each quantum barrier layer of the active layer, the composition ratio of In is greater than the composition ratio of Al.
7. The laser according to any one of claims 1 to 6, characterized in that The materials used in the lower waveguide layer include Al, In, Ga and N, and the materials used in the upper waveguide layer include Al, In, Ga and N.
8. The laser according to claim 7, characterized in that The difference between the composition ratio of In in the three materials of Al, In and Ga in the lower quantum barrier layer and the composition ratio of In in the three materials of Al, In and Ga in the lower waveguide layer is greater than or equal to 9% and less than or equal to 20%.
9. The laser according to claim 7 or 8, characterized in that: The difference between the composition ratio of In in the three materials of Al, In and Ga in the upper quantum barrier layer and the composition ratio of In in the three materials of Al, In and Ga in the upper waveguide layer is greater than or equal to 0% and less than or equal to 14%.
10. The laser according to claim 1 or 2, characterized in that: In the lower quantum barrier layer, the proportion of Al in the three materials of Al, In and Ga is greater than or equal to 8% and less than or equal to 15%; in the upper quantum barrier layer, the proportion of Al in the three materials of Al, In and Ga is greater than or equal to 10% and less than or equal to 18%; in the middle quantum barrier layer, the proportion of Al in the three materials of Al, In and Ga is greater than or equal to 15% and less than or equal to 25%.
11. The laser according to any one of claims 1 to 10, characterized in that The active layer also includes a first quantum well layer and a second quantum well layer, the first quantum well layer is located between the lower quantum barrier layer and the middle quantum barrier layer, the second quantum well layer is located between the middle quantum barrier layer and the upper quantum barrier layer, the materials used in the first quantum well layer include In, Ga and N, and the materials used in the second quantum well layer include In, Ga and N.
12. The laser according to claim 11, characterized in that In the first quantum well layer, the composition ratio of In in the two materials In and Ga is greater than or equal to 10% and less than or equal to 35%; and / or, In the second quantum well layer, the composition ratio of In in the two materials In and Ga is greater than or equal to 10% and less than or equal to 35%.
13. An optical transmitter, characterized in that: include: A driver and the laser according to any one of claims 1 to 12, wherein the driver is used to drive the laser to emit light.
14. An optical module, characterized in that: include: An optical receiver and an optical transmitter as claimed in claim 13.