Semiconductor pulse laser

Abstract

The invention discloses a semiconductor pulse laser, and belongs to the technical field of semiconductors. The semiconductor pulse laser comprises a first DFB region, an absorption region and a second DFB region which are sequentially distributed along a first direction, wherein the first direction is a light propagation direction; the semiconductor pulse laser comprises an epitaxial structure, and the epitaxial structure comprises a substrate; the active region is positioned on one side of the thickness direction of the substrate; the grating layer is located on the side, away from the substrate, of the active region, and the grating layer comprises grating structures located in the first DFB region and the second DFB region; the ridge waveguide structure is located on the side, away from the substrate, of the grating layer, and the ridge waveguide structure comprises a first structure located in the first DFB region and the second DFB region and a second structure located in the absorption region; and an electrical isolation structure between the first structure and the second structure. The laser pulse generation efficiency and quality can be improved, and the performance of the laser is improved.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to a semiconductor pulse laser. Background Art

[0002] DFB-SA (distributed feedback-saturable absorber integrated) laser is a monolithic integrated semiconductor pulse laser, which integrates a saturable absorber (SA) on a DFB laser, which can greatly improve the integration and compactness of the laser.

[0003] In the related art, the SA in the DFB-SA laser is located at the end face of the laser to achieve the pulse effect. However, due to the inevitable errors in the actual manufacturing process, especially in the process of cutting the wafer into a DFB-SA laser, the SA is located at the end face of the laser, and the length of the SA is relatively short. The process deviation of the cutting position has a greater impact on the SA, resulting in a deviation between the actual length of the SA and its design specifications. The laser performance (especially the pulse effect) has extremely high requirements for the precision of the SA length. The deviation of the SA length will directly weaken the generation efficiency and quality of the laser pulse, and may even make it impossible to form a laser pulse. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the related art. To this end, the present application proposes a semiconductor pulse laser, which can improve the generation efficiency and quality of laser pulses and improve the performance of the laser.

[0005] The present application provides a semiconductor pulse laser, comprising a first DFB region, an absorption region, and a second DFB region sequentially distributed along a first direction, wherein the first direction is a light propagation direction; the semiconductor pulse laser comprises an epitaxial structure, wherein the epitaxial structure comprises:

[0006] substrate;

[0007] an active region, located on one side of the substrate in a thickness direction, wherein the thickness direction is perpendicular to the first direction;

[0008] a grating layer, located on a side of the active region away from the substrate, the grating layer comprising a grating structure located in the first DFB region and the second DFB region;

[0009] a ridge waveguide structure, located at a side of the grating layer away from the substrate, the ridge waveguide structure comprising a first structure located in the first DFB region and the second DFB region and a second structure located in the absorption region;

[0010] The electrical isolation structure is located between the first structure and the second structure.

[0011] According to one embodiment of the present application, the semiconductor pulse laser further includes an anti-reflection film;

[0012] The anti-reflection film is located at two opposite ends of the epitaxial structure along the first direction.

[0013] According to one embodiment of the present application, the ridge waveguide structure includes a highly doped semiconductor layer and a waveguide layer;

[0014] The highly doped semiconductor layer is located on a side of the grating layer away from the substrate, and the waveguide layer is located on a side of the highly doped semiconductor layer away from the grating layer.

[0015] According to an embodiment of the present application, the width of the ridge waveguide structure along the second direction is smaller than the width of the grating layer along the second direction, and the second direction is perpendicular to the first direction and the thickness direction respectively.

[0016] According to one embodiment of the present application, the ridge waveguide structure is located in the middle of the grating layer along the second direction.

[0017] According to one embodiment of the present application, the semiconductor pulse laser further includes a first electrode and a second electrode;

[0018] The first electrode covers the ridge waveguide structure and the grating layer, and the second electrode is located on a side of the substrate away from the active region.

[0019] According to one embodiment of the present application, the active region includes a first confinement layer, a quantum well layer, and a second confinement layer;

[0020] The first confinement layer, the quantum well layer and the second confinement layer are sequentially stacked and located between the substrate and the grating layer.

[0021] According to one embodiment of the present application, the electrical isolation structure includes a groove.

[0022] According to an embodiment of the present application, the lengths of the first DFB region and the second DFB region along the first direction are the same or different;

[0023] A length difference between the first DFB region and the second DFB region along the first direction does not exceed 50 um.

[0024] According to an embodiment of the present application, the total length of the first DFB region and the second DFB region along the first direction is 100um-1000um; and / or,

[0025] The length of the absorption zone along the first direction is 10um-50um.

[0026] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0027] An absorption region is arranged between the first DFB region and the second DFB region, laser is generated through the first DFB region and the second DFB region, and laser pulses are generated through the absorption region, and the grating structures in the first DFB region and the second DFB region provide a high reflectivity, so that the absorption region is located between the first DFB region and the second DFB region, which does not affect the realization of the pulse, and can avoid the influence of the manufacturing process error on the absorption region, thereby improving the generation efficiency and quality of the laser pulse and improving the performance of the laser; moreover, the first DFB region, the second DFB region and the absorption region are integrated on the epitaxial structure, which promotes the integration and miniaturization of the semiconductor pulse laser;

[0028] Furthermore, an anti-reflection film is provided at the two opposite ends of the epitaxial structure along the first direction, which can reduce the influence of random phase errors on the laser pulse output, improve the stability of the single-mode output of the semiconductor pulse laser, and enhance the wavelength accuracy of the laser pulse. The anti-reflection film allows the optical signal to be transmitted freely at the two opposite ends of the epitaxial structure along the first direction, thereby simplifying the optical path design of the semiconductor pulse laser and further promoting the miniaturization of the semiconductor pulse laser.

[0029] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 is a schematic diagram of the structure of a semiconductor pulse laser provided in an embodiment of the present application;

[0032] Figure 2 is a schematic cross-sectional view of the structure of a semiconductor pulse laser provided in an embodiment of the present application;

[0033] Figure 3 It is a top view of the epitaxial structure and anti-reflection film in the semiconductor pulse laser provided in the embodiment of the present application. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0035] With the rapid advancement of science and technology and the continuous updating of practical application needs, the miniaturization of semiconductor pulse lasers has become a core research direction in the field of semiconductor technology. The miniaturization of semiconductor pulse lasers can make lasers compact, light, low power, easy to carry and integrate, and can be applied to a wider range of technical scenarios (such as industry, medical treatment, communication and scientific research, etc.).

[0036] With the progress and development of materials science and integration technology, as well as the in-depth application of self-Q-switching technology, semiconductor pulse lasers have been continuously developing from traditional large volume, high cost and high energy consumption to miniaturization, integration and low power consumption. Some new materials (such as nanophotonic chips and thin-film lithium niobate, etc.) have excellent optical and electro-optical properties, which can accurately control the generation of laser pulses, ensure the efficient and stable operation of the laser, and contribute to the miniaturization of the laser. With the continuous improvement of the integration level of semiconductor pulse lasers, the performance and stability of semiconductor pulse lasers can be further improved by closely integrating lasers and other photonic devices, and realizing efficient and stable photonic integrated circuits. Self-Q-switching technology is a technology that does not require the use of additional Q switches and modulators in the laser resonant cavity. In related technologies, self-Q-switching technology generally sets a saturable absorber dye as a Q switch. The saturable absorber dye is usually expensive and large in size, which is not conducive to the miniaturization and integration of the laser. Therefore, integrating the saturable absorber directly into the semiconductor pulse laser has become a key direction for future research.

[0037] With the continuous innovation and breakthrough of technology, the miniaturization development of semiconductor pulse lasers will show a more diversified trend. In the future, miniaturized semiconductor pulse lasers will pay more attention to performance improvement and cost reduction to meet the application needs in a wider range of technical fields. At the same time, with the continuous development of Internet and Internet of Things technologies, miniaturized semiconductor pulse lasers will gradually realize networking and intelligence, providing more convenient and efficient services for a wider range of technical fields. The miniaturization development of semiconductor pulse lasers is an important trend in the field of semiconductor technology, which will promote the widespread application and innovative development of semiconductor technology. With the continuous advancement of technology and the continuous expansion of applications, the application fields and application prospects of miniaturized semiconductor pulse lasers will be continuously broadened.

[0038] The DFB-SA laser is a monolithic integrated semiconductor pulse laser. Integrating a saturable absorber on a DFB (Distributed Feedback) laser can improve integration and compactness. This design can reduce the volume and weight of the saturable absorber, simplify the system structure, and reduce costs and maintenance difficulties. The DFB-SA laser has the ability to modulate quickly. When the absorber is in an absorbing state, the generation of laser light can be effectively suppressed; when the absorber changes to a transparent state, the laser light will be rapidly excited and form a short pulse. The DFB-SA laser has a "Q-switching" mechanism that can generate high-power short-pulse laser light, which is suitable for application scenarios in technical fields such as fast response and optical neural network computing.

[0039] In the related art, the SA in the DFB-SA laser is located at one end of the laser. During the manufacturing process, it is first necessary to use thin film deposition, etching and other processes to prepare the indium phosphorus material into a wafer. Then, the wafer is cut using a cleavage process to obtain a DFB-SA laser. However, due to the inevitable errors in the actual manufacturing process, especially in the process of cutting the wafer into a DFB-SA laser, the SA is located at one end of the laser, and the length of the SA is relatively short. The process deviation of the cutting position has a greater impact on the SA, resulting in a deviation between the actual length of the SA and its design specifications. The performance of the laser (especially the pulse effect) has extremely high requirements for the accuracy of the SA length. The deviation in the length of the SA will directly weaken the generation efficiency and quality of the laser pulse, and may even result in the complete inability to form a laser pulse.

[0040] In addition, in the related art, the DFB-SA laser adopts HR-AR (high reflection-anti-reflection) coating technology to coat the HR film and AR film on the two end faces of the laser. Among them, the HR film has an extremely high reflectivity, which will amplify the adverse effects of the random phase error generated during the wafer cleavage process, thereby significantly reducing the overall single-mode stability of the DFB-SA laser. Especially for applications in the fields of high-precision optical communications and optical computing, the impact of the cleavage process error on the SA length and the amplification of the random phase error by the HR film will reduce the overall performance and stability of the semiconductor pulse laser.

[0041] At the same time, in the related technology, the HR film on one end face of the HR-AR coated semiconductor pulse laser has a high reflectivity characteristic, which will limit the free input and output of optical signals, affect the effective use of optical signals, and hinder the development of semiconductor pulse lasers in miniaturization and integration.

[0042] Based on this, an embodiment of the present application provides a semiconductor pulse laser.

[0043] The semiconductor pulse laser provided in the embodiments of the present application is described below with reference to the accompanying drawings.

[0044] Figure 1 A schematic diagram of the structure of a semiconductor pulse laser provided in an embodiment of the present application.

[0045] The semiconductor pulse laser provided in the embodiment of the present application comprises a first DFB (Distributed Feedback) region 11, an absorption region 10 and a second DFB region 12 sequentially distributed along a first direction X, wherein the first direction X is the light propagation direction. Figure 1 As shown, the first DFB region 11, the absorption region 10 and the second DFB region 12 can be arranged at intervals along the first direction X. The first DFB region 11 and the second DFB region 12 mainly play the role of generating lasers and lasing the required wavelength. The absorption region 10 realizes photoelectric conversion by applying a reverse voltage to realize carrier absorption, and performs electro-optical conversion after absorption saturation, periodically changing the Q value (Quality factor) of the laser to generate laser pulses. Among them, the absorption region 10 can be a SA (Saturable Absorber) region.

[0046] The first direction X is the light propagation direction, that is, one of the two opposite ends of the semiconductor pulse laser along the first direction X is the light emission end, and the other end is the light incident end. Light is incident from the incident end of the semiconductor pulse laser, resonates inside the laser, and when sufficient light intensity is reached, the light is emitted from the output end of the semiconductor pulse laser.

[0047] The semiconductor pulse laser includes an epitaxial structure 100, and the epitaxial structure 100 includes a substrate 1. The substrate 1 can be used as a base to provide physical support for other film layers. The band gap width of the substrate 1 should meet the requirements of optical computing and optical communication for the band. The material of the substrate 1 can include indium phosphorus material, etc. The thickness of the substrate 1 can be 100um.

[0048] The epitaxial structure 100 may further include an active region 2, which is located on one side of the thickness direction H of the substrate 1, and the thickness direction H is perpendicular to the first direction X. Figure 1 As shown, the active region 2 is located above the substrate 1. The active region 2 can serve as a region for electron transition and the formation of upper and lower energy level population inversion, which can promote the formation of laser pulses. The material of the active region 2 can include III-V group quaternary compound semiconductor materials, such as InGaAsP (indium gallium arsenide phosphide) or AlGaAsP (aluminum gallium arsenide phosphide). The thickness of the active region 2 can be tens of nanometers.

[0049] The epitaxial structure 100 may further include a grating layer 3, which is located on a side of the active region 2 facing away from the substrate 1. Figure 1As shown, the grating layer 3 is located above the active region 2. The grating layer 3 includes a grating structure 31 located in the first DFB region 11 and the second DFB region 12, and the absorption region 10 is not provided with the grating structure 31. In some embodiments, the grating layer 3 may further include a grating auxiliary layer 32, and the grating structure 31 is located in the grating auxiliary layer 32. The grating structure 31 is used to promote the semiconductor pulse laser to achieve stable and accurate single-mode lasing at the required wavelength. The grating auxiliary layer 32 is used to support and protect the grating structure 31 to improve the performance and stability of the grating structure 31.

[0050] In some embodiments, the grating structure 31 may include at least one first grating and at least one second grating extending along the second direction Y. The second direction Y is perpendicular to the plane where the first direction X and the thickness direction H are located, that is, the second direction Y is perpendicular to the first direction X and perpendicular to the thickness direction H. At least one first grating is located in the first DFB region 11 and is arranged at intervals along the first direction X, and at least one second grating is located in the second DFB region 12 and is arranged at intervals along the first direction X. The number of first gratings in the first DFB region 11 and the number of second gratings in the second DFB region 12 may be the same or different. The first grating and the second grating are arranged in the first DFB region 11 and the second DFB region 12, so that light of a specific wavelength can be reflected back and forth and amplified between the incident end and the output end of the semiconductor pulse laser, thereby realizing single-mode laser output.

[0051] The epitaxial structure 100 may further include a ridge waveguide structure 4, which is located on a side of the grating layer 3 facing away from the substrate 1. Figure 1 As shown, the ridge waveguide structure 4 is located above the grating layer 3. The ridge waveguide structure 4 includes a first structure 41 located in the first DFB region 11 and the second DFB region 12 and a second structure 42 located in the absorption region 10. The first structure 41 of the ridge waveguide structure 4 may include a first substructure located in the first DFB region 11 and a second substructure located in the second DFB region 12, and the second structure 42 is located between the first substructure and the second substructure. The materials of the first structure 41 and the second structure 42 of the ridge waveguide structure 4 may be the same, and the first structure 41 and the second structure 42 may be an integrally formed structure, that is, the first structure 41 and the second structure 42 may be formed by the same epitaxial process. The setting of the ridge waveguide structure 4 helps to improve the performance of the semiconductor pulse laser.

[0052] The epitaxial structure 100 may also include an electrical isolation structure 5, which is located between the first structure 41 and the second structure 42 to isolate the first structure 41 from the second structure 42. For example, the electrical isolation structure 5 may include a first electrical isolation substructure and a second electrical isolation substructure. The first electrical isolation substructure is located between the first substructure and the second structure 42 of the ridge waveguide structure 4 to isolate the first substructure from the second structure 42 to avoid crosstalk between the first substructure and the second structure 42. The second electrical isolation substructure is located between the second structure 42 and the second substructure of the ridge waveguide structure 4 to isolate the second structure 42 from the second substructure to avoid crosstalk between the second structure 42 and the second substructure to ensure the normal and stable operation of the semiconductor pulse laser. Among them, the isolation resistance of the first electrical isolation substructure and the second electrical isolation substructure can both be 3000Ω-5000Ω.

[0053] It should be noted that if Figure 1 and Figure 3 As shown, the thickness of the electrical isolation structure 5 along the thickness direction H can be the same as the thickness of the ridge waveguide structure 4 along the thickness direction H, and the width of the electrical isolation structure 5 along the second direction Y can be the same as the width of the ridge waveguide structure 4 along the second direction Y, so as to completely isolate the first structure 41 from the second structure 42.

[0054] In the embodiment of the present application, the grating structure 31 in the first DFB region 11 and the second DFB region 12 can provide a higher reflectivity and meet the specific wavelength requirements of the lasing, so that the light of the specific wavelength is reflected back and forth between the incident end and the output end of the semiconductor pulse laser and amplified, thereby outputting a stable single-mode laser pulse. The absorption region 10 has a unique carrier absorption characteristic, and can modulate and compress the laser pulse to improve the quality of the laser pulse. Moreover, in the process of cutting the wafer into a semiconductor pulse laser, the absorption region 10 is located between the first DFB region 11 and the second DFB region 12, avoiding the influence of the cutting position error generated by the cleavage process on the absorption region 10 (compared with the absorption region 10, the length of the first DFB region 11 and the second DFB region 12 is longer, and the process deviation of the cutting position has little effect on the length of the first DFB region 11 and the second DFB region 12, and the effect on the performance of the semiconductor pulse laser can be ignored), so as to achieve a higher quality and high stability laser pulse output. Furthermore, the first DFB region 11 , the second DFB region 12 and the absorption region 10 are integrated together on the epitaxial structure 100 , which promotes the integration and miniaturization of the semiconductor pulse laser.

[0055] In some embodiments, the first grating and the second grating in the grating structure 31 may include a zero-order grating and a first-order grating. In the process of manufacturing the grating structure 31, a sampled grating is used by REC technology (Recon-Struction-Equivalent-Chirp, reconstruction equivalent chirp technology) to equivalently design the period of the grating structure 31. First, a zero-order grating is formed by holographically exposing the upper surface of the active region 2 (the active region 2 is formed by epitaxial growth on the substrate 1). Then, the obtained zero-order grating is subjected to secondary epitaxy by using photolithography technology to integrate a first-order grating. Among them, the Bragg wavelength of the first-order grating is approximately equal to the lasing wavelength of the semiconductor pulse laser.

[0056] The related technology integrates multiple semiconductor pulse lasers into an array, so that the emission wavelength intervals of each semiconductor pulse laser are consistent to achieve overall periodicity, thereby meeting the high requirements for computing power in the field of optical computing and communications. However, the emission wavelength intervals of these semiconductor pulse lasers are extremely small (a few tenths of a nanometer in size), and ordinary lithography machines cannot technically achieve the manufacturing precision required for semiconductor pulse lasers.

[0057] In this embodiment, a zero-order grating is first formed, and then a first-order grating is formed, so as to achieve a technical effect of equivalent nanometer level through micrometer level process, and promote the precise lasing of semiconductor pulse laser at its required wavelength.

[0058] In some embodiments, Figure 2 As shown, Figure 2 It is a cross-sectional schematic diagram of a semiconductor pulse laser, the cross section is parallel to the plane where the thickness direction H and the second direction Y are located, and is perpendicular to the first direction X. The width of the ridge waveguide structure 4 along the second direction Y is less than the width of the grating layer 3 along the second direction Y. The width of the ridge waveguide structure 4 along the second direction Y can be 2um-2.5um. The length of the ridge waveguide structure 4 along the first direction X can be the same as the length of the grating layer 3 along the first direction X. The thickness of the ridge waveguide structure 4 along the thickness direction H can be 2um-3um. The ridge waveguide structure 4 improves its coupling efficiency with the optical fiber through the refractive index difference between it and the air on both sides, limits the propagation of light in the ridge waveguide structure 4 to avoid light leakage and light loss, thereby improving the effect of the semiconductor pulse laser outputting laser pulses. At the same time, the ridge waveguide structure 4 can increase the modulation bandwidth of the semiconductor pulse laser and reduce the threshold current, thereby improving the performance and life of the semiconductor pulse laser.

[0059] In the process of manufacturing the semiconductor pulse laser, an initial waveguide structure may be first formed on the grating layer 3 , and then, the edges of the initial waveguide structure on two opposite sides along the second direction Y are etched by an etching process to obtain a ridge waveguide structure 4 .

[0060] In some embodiments, the ridge waveguide structure 4 is located in the middle of the grating layer 3 along the second direction Y.

[0061] When etching the edges of the initial waveguide structure on both sides along the second direction Y, the etching widths on both sides can be the same, so that the ridge waveguide structure 4 is set in the middle above the grating layer 3 along the second direction Y, further enhancing the confinement of the ridge waveguide structure 4 on light, improving the quality of light propagation, and at the same time being able to improve the effect of the single-mode output of the semiconductor pulse laser.

[0062] In some embodiments, the semiconductor pulse laser further includes an anti-reflection film 6, which is located at opposite ends of the epitaxial structure 100 along the first direction X to cover the incident end face and the exit end face of the semiconductor pulse laser. For example, the anti-reflection film 6 may include two anti-reflection sub-film layers, which are respectively disposed on two end faces at opposite ends of the epitaxial structure 100 along the first direction X. One anti-reflection sub-film layer of the anti-reflection film 6 covers the incident end face of the semiconductor pulse laser, and the other anti-reflection sub-film layer covers the exit end face of the semiconductor pulse laser.

[0063] In the related art, a DFB-SA laser is provided with a high reflective film on the SA part. However, the high reflective film will make the end face have a very high reflectivity, which will amplify the random phase change on the end face of the semiconductor pulse laser due to the error of the cleavage process, reduce the edge mode suppression ratio of the semiconductor pulse laser, and cause the semiconductor pulse laser to produce multi-longitudinal mode phenomenon, thereby affecting the accuracy of signal transmission and the output of laser pulses.

[0064] The embodiment of the present application can reduce the reflectivity of the two end faces of the semiconductor pulse laser by setting the anti-reflection film 6 on the two opposite end faces of the first DFB region 11 and the second DFB region 12 along the first direction X, so as to eliminate the influence of random phase errors and improve the stability and accuracy of the single-mode output of the laser pulse. At the same time, since the anti-reflection films are set on the two opposite end faces of the first DFB region 11 and the second DFB region 12 along the first direction X, both end faces can be used as the incident end or the output end of the light, so that the transmission of the optical signal is freer and smoother, and the calculation dimension of the optical calculation is improved, thereby improving the performance of the semiconductor pulse laser, and making the semiconductor pulse laser applicable to a wider and more complex technical field.

[0065] In some embodiments, the electrical isolation structure 5 includes a groove, that is, the first structure 41 and the second structure 42 can be isolated by the groove. For example, the first electrical isolation substructure includes a groove (i.e., the first groove), and the second electrical isolation substructure includes a groove (i.e., the second groove). The first groove is located between the first DFB region 11 and the absorption region 10 to separate the first substructure of the first structure 41 of the ridge waveguide structure 4 from the second structure 42. The second groove is located between the absorption region 10 and the second DFB region 12 to separate the second structure 42 of the ridge waveguide structure 4 from the second substructure of the first structure 41. Figure 1 As shown, in the thickness direction H, the bottoms of the first groove and the second groove are located in the same plane as the bottom of the ridge waveguide structure 4, that is, the thickness of the first groove and the second groove along the thickness direction H is consistent with the thickness of the ridge waveguide structure 4 along the thickness direction H. Figure 3 As shown, the first groove and the second groove extend along the second direction Y and penetrate the ridge waveguide structure 4 , that is, the width of the first groove and the second groove along the second direction Y is consistent with the width of the ridge waveguide structure 4 along the second direction Y.

[0066] In some embodiments, the ridge waveguide structure 4 includes a highly doped semiconductor layer 7 and a waveguide layer 8. The highly doped semiconductor layer 7 is located on the side of the grating layer 3 facing away from the substrate 1, and the waveguide layer 8 is located on the side of the highly doped semiconductor layer 7 facing away from the grating layer 3. Figure 1 As shown, the highly doped semiconductor layer 7 is located above the grating layer 3, and the waveguide layer 8 is located above the highly doped semiconductor layer 7. The material of the highly doped semiconductor layer 7 may include InGaAs (indium gallium arsenide).

[0067] The first structure 41 (including the first substructure and the second substructure) and the second structure 42 of the ridge waveguide structure 4 may both include a highly doped semiconductor layer 7. A large number of ions exist in the highly doped semiconductor layer 7, which can improve the electrical conductivity, so that the first structure 41 (including the first substructure and the second substructure) and the second structure 42 of the ridge waveguide structure 4 form three high conductivity regions. The electrical isolation structure 5 does not have a highly doped semiconductor material and has a low electrical conductivity, so that the first electrical isolation substructure and the second electrical isolation substructure of the electrical isolation structure 5 form two low conductivity regions. The high conductivity region where the first substructure of the first structure 41 is located and the high conductivity region where the second structure 42 is located are separated by the low conductivity region where the first electrical isolation substructure is located, and the high conductivity region where the second structure 42 is located and the high conductivity region where the second substructure is located are separated by the low conductivity region where the second electrical isolation substructure is located. As a result, the high conductivity region and the low conductivity region form a series-parallel circuit.

[0068] In some embodiments, the semiconductor pulse laser further includes a first electrode 91 and a second electrode 92. The first electrode 91 covers the ridge waveguide structure 4 and the grating layer 3, and the second electrode 92 is located on a side of the substrate 1 away from the active region 2.

[0069] like Figure 2 As shown, the first electrode 91 covers the upper surface of the ridge waveguide structure 4 and the two opposite side surfaces along the second direction Y, that is, the first electrode 91 covers the upper surface of the first structure 41 (including the first substructure and the second substructure) of the ridge waveguide structure 4 and the two opposite side surfaces along the second direction Y, as well as the upper surface of the second structure 42 and the two opposite side surfaces along the second direction Y. The width of the ridge waveguide structure 4 along the second direction Y is smaller than the width of the grating layer 3 along the second direction Y, therefore, the first electrode 91 also covers part of the upper surface of the grating layer 3 (that is, the part of the upper surface not covered by the ridge waveguide structure 4). The first electrode 91 does not cover the electrical isolation structure 5.

[0070] The second electrode 92 is located below the substrate 1 and covers the bottom surface of the substrate 1. In the semiconductor pulse laser, by injecting current into the first electrode 91 and the second electrode 92, the electrons and holes in the active region are stimulated to recombine to emit light. The first electrode 91 and the second electrode 92 are necessary conditions to ensure that the semiconductor pulse laser outputs laser pulses normally. The materials of the first electrode 91 and the second electrode 92 may include gold.

[0071] In some embodiments, the active region 2 includes a first confinement layer 21 , a quantum well layer 20 , and a second confinement layer 22 . The first confinement layer 21 , the quantum well layer 20 , and the second confinement layer 22 are sequentially stacked between the substrate 1 and the grating layer 3 .

[0072] like Figure 1 and Figure 2 As shown, the second confinement layer 22 is located above the substrate 1 , the quantum well layer 20 is located above the second confinement layer 22 , and the first confinement layer 21 is located between the quantum well layer 20 and the grating layer 3 .

[0073] In a semiconductor pulse laser, the quantum well layer 20 can confine electrons and holes in a smaller space to improve the carrier recombination efficiency, thereby improving the luminous efficiency and output power of the laser, and can modulate the emission wavelength, enhance the quantum effect, and thus improve the performance of the laser. The first confinement layer 21 is located above the quantum well layer 20, and the second confinement layer 22 is located below the quantum well layer 20, which can limit the escape of carriers and ensure that the current flows into the quantum well layer 20, and can limit the propagation of light so that the light propagates along the waveguide direction, thereby improving the quality of the output laser pulse. At the same time, the first confinement layer 21 and the second confinement layer 22 can form a resonant cavity together with the quantum well layer 20, providing an effective optical feedback mechanism, thereby ensuring the single-frequency resonance of the semiconductor pulse laser and the stable output of the laser pulse.

[0074] In some embodiments, the lengths of the first DFB region 11 and the second DFB region 12 along the first direction X are the same or different.

[0075] like Figure 1 As shown, the lengths of the first DFB region 11 and the second DFB region 12 along the first direction X may be different, that is, the absorption region 10 may not be located in the middle in the first direction X. The lengths of the first DFB region 11 and the second DFB region 12 along the first direction X may also be the same, that is, the absorption region 10 may be located in the middle in the first direction X.

[0076] In some embodiments, the length difference between the first DFB region 11 and the second DFB region 12 along the first direction X does not exceed 50 um.

[0077] When the lengths of the first DFB region 11 and the second DFB region 12 along the first direction X are different, the coupling efficiency of the first grating in the first DFB region 11 and the second grating in the second DFB region 12 will be different, thereby affecting the output power, polarization characteristics, spectral line width and some other performance parameters of the semiconductor pulse laser. Therefore, the difference in length between the first DFB region 11 and the second DFB region 12 along the first direction X cannot be too large to reduce the internal loss of the semiconductor pulse laser and ensure that the semiconductor pulse laser can stably output laser pulses.

[0078] In some embodiments, the total length of the first DFB region 11 and the second DFB region 12 along the first direction X is 100um-1000um. The total length of the first DFB region 11 and the second DFB region 12 along the first direction X does not exceed 1000um to meet the needs of miniaturization and integration of semiconductor pulse lasers. For example, the length of the first DFB region 11 along the first direction X can be 150um, and the length of the second DFB region 12 along the first direction X can be 100um, meeting the needs of miniaturization of semiconductor pulse lasers.

[0079] In some embodiments, the length of the absorption zone 10 along the first direction X is 10um-50um. The length of the absorption zone 10 along the first direction X is positively correlated with the total length of the first DFB zone 11 and the second DFB zone 12 along the first direction X. By collaboratively designing the lengths of the first DFB zone 11, the second DFB zone 12 and the absorption zone 10 along the first direction X, the absorption characteristics can be matched, which helps to stabilize the output wavelength and power of the semiconductor pulse laser, thereby improving the performance of the laser. When the total length of the first DFB zone 11 and the second DFB zone 12 along the first direction X is set shorter, the length of the absorption zone 10 along the first direction X is also set shorter, which can further meet the needs of miniaturization of semiconductor pulse lasers.

[0080] The semiconductor pulse laser provided in the embodiment of the present application is compared with the DFB-SA laser (SA is set on one side of the DFB) in the related art. The main performance indicators of the lasers in the embodiment of the present application and the related art are tested using standard test methods, including pulse frequency and single-mode rate. Under the same test conditions, compared with the DFB-SA laser in the related art, the semiconductor pulse laser provided in the embodiment of the present application has a higher single-mode rate and more uniform pulse frequency and power.

[0081] The semiconductor pulse laser provided in the embodiments of the present application can be applied to a variety of technical fields, such as high-speed optical communication, artificial neural networks and photon computing, laser radar (LiDAR) and photon integration.

[0082] In the field of high-speed optical communications, semiconductor pulse lasers, as the core light source of high-speed optical communication systems, have the characteristics of compact structure, dynamic single mode, etc., and can provide stable and high-quality optical signals. Moreover, semiconductor pulse lasers can support the realization of high data transmission rates while maintaining low noise levels and good optical feedback stability to ensure accurate transmission of optical signals. In addition, the wavelength tunability of semiconductor pulse lasers also enables them to adapt to the needs of optical communication systems of different wavelengths, enhancing the flexibility and scalability of the system.

[0083] In the field of artificial neural networks and photonic computing, the realization method of monolithic integrated photonic pulse neurons based on semiconductor pulse lasers combines semiconductor pulse lasers with specific circuits to realize photonic pulse neurons with biological neuron characteristics. This method has potential application value in the field of artificial neural networks and photonic computing, and can reduce system complexity and power consumption, improve computing speed, and build a more efficient and intelligent photonic computing system.

[0084] In the field of LiDAR, laser radar uses laser beams to measure distance and speed. Semiconductor pulse lasers calculate the distance of target objects by emitting laser pulses and receiving their echoes. This laser pulse has an extremely short duration (such as nanoseconds), which makes the energy of the laser pulse highly concentrated in a very short time, thereby improving the accuracy of distance measurement.

[0085] In the field of photonic integration, semiconductor pulse lasers are one of the indispensable key components in photonic integrated modules and systems. Through the integration and collaboration of semiconductor pulse lasers with other photonic devices, photonic integrated modules and systems with rich functions and excellent performance can be constructed. These photonic integrated modules and systems are widely used in data centers, edge computing, optical interconnection and other fields, providing strong support for the rapid development of information technology.

[0086] In summary, according to the semiconductor pulse laser provided by the present application, an absorption zone 10 is set between the first DFB zone 11 and the second DFB zone 12, laser is generated by the first DFB zone 11 and the second DFB zone 12, and laser pulses are generated by the absorption zone 10. The grating structure 31 in the first DFB zone 11 and the second DFB zone 12 provides a higher reflectivity, so that the absorption zone 10 is located between the first DFB zone 11 and the second DFB zone 12, which does not affect the realization of the pulse, and can avoid the influence of the manufacturing process error on the absorption zone 10, thereby improving the generation efficiency and quality of the laser pulse and improving the laser performance; moreover, the first DFB zone 11, the second DFB zone 12 and the absorption zone 10 are integrated on the epitaxial structure 100, which promotes the integration and miniaturization of the semiconductor pulse laser. Furthermore, an anti-reflection film 6 is provided at the two opposite ends of the epitaxial structure 100 along the first direction X, which can reduce the influence of random phase errors on the laser pulse output, improve the stability of the single-mode output of the semiconductor pulse laser, and enhance the wavelength accuracy of the laser pulse. The anti-reflection film 6 allows the optical signal to be freely transmitted at the two opposite ends of the epitaxial structure 100 along the first direction X, thereby simplifying the optical path design of the semiconductor pulse laser and further promoting the miniaturization of the semiconductor pulse laser.

[0087] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0088] In the description of the present application, “plurality” means two or more.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0090] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A semiconductor pulse laser, characterized in that: It includes a first DFB region, an absorption region, and a second DFB region sequentially distributed along a first direction, wherein the first direction is a light propagation direction; The semiconductor pulse laser comprises an epitaxial structure, and the epitaxial structure comprises: substrate; an active region, located on one side of the substrate in a thickness direction, wherein the thickness direction is perpendicular to the first direction; a grating layer, located on a side of the active region away from the substrate, the grating layer comprising a grating structure located in the first DFB region and the second DFB region; a ridge waveguide structure, located at a side of the grating layer away from the substrate, the ridge waveguide structure comprising a first structure located in the first DFB region and the second DFB region and a second structure located in the absorption region; The electrical isolation structure is located between the first structure and the second structure.

2. The semiconductor pulse laser according to claim 1, characterized in that: The semiconductor pulse laser also includes an anti-reflection film; The anti-reflection film is located at two opposite ends of the epitaxial structure along the first direction.

3. The semiconductor pulse laser according to claim 1, characterized in that: The ridge waveguide structure comprises a highly doped semiconductor layer and a waveguide layer; The highly doped semiconductor layer is located on a side of the grating layer away from the substrate, and the waveguide layer is located on a side of the highly doped semiconductor layer away from the grating layer.

4. The semiconductor pulse laser according to claim 1, characterized in that: The width of the ridge waveguide structure along a second direction is smaller than the width of the grating layer along the second direction, and the second direction is perpendicular to the first direction and the thickness direction respectively.

5. The semiconductor pulse laser according to claim 4, characterized in that: The ridge waveguide structure is located in the middle of the grating layer along the second direction.

6. The semiconductor pulse laser according to claim 4, characterized in that: The semiconductor pulse laser also includes a first electrode and a second electrode; The first electrode covers the ridge waveguide structure and the grating layer, and the second electrode is located on a side of the substrate away from the active region.

7. The semiconductor pulse laser according to claim 1, characterized in that: The active region includes a first confinement layer, a quantum well layer and a second confinement layer; The first confinement layer, the quantum well layer and the second confinement layer are sequentially stacked and located between the substrate and the grating layer.

8. The semiconductor pulse laser according to claim 1, characterized in that: The electrical isolation structure includes a groove.

9. The semiconductor pulse laser according to claim 1, characterized in that: The lengths of the first DFB region and the second DFB region along the first direction are the same or different; A length difference between the first DFB region and the second DFB region along the first direction does not exceed 50 um.

10. The semiconductor pulse laser according to any one of claims 1 to 9, characterized in that: The total length of the first DFB region and the second DFB region along the first direction is 100um-1000um; and / or, The length of the absorption zone along the first direction is 10um-50um.

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