Semiconductor laser and manufacturing method thereof

Abstract

The embodiment of the invention provides a semiconductor laser and a manufacturing method thereof, relates to the technical field of semiconductor lasers, and is used for reducing the chirp problem of the semiconductor laser. The semiconductor laser includes: a substrate; the ridge waveguide is arranged on the substrate and extends along the first direction of the substrate; the grating is arranged at the top of the ridge waveguide, the grating comprises a first area and a second area which are periodically arranged in the first direction, the first area comprises a semiconductor material, the second area comprises an insulating medium material, and the refractive index of the insulating medium material is larger than that of the semiconductor material.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor lasers, and in particular to a semiconductor laser and a method for manufacturing the same. Background Art

[0002] With the increasing user demand for high-bitrate services such as high-definition video and high-performance edge computing in recent years, the International Telecommunication Union-World Telecommunication Standards Assembly has successively announced relevant specifications for 10G asymmetric passive optical networks and 10G symmetric passive optical networks. These relevant specifications have put forward low chirp requirements for semiconductor lasers. Summary of the invention

[0003] The embodiments of the present application provide a semiconductor laser and a method for manufacturing the same, which are used to reduce the chirp problem of the semiconductor laser.

[0004] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0005] In a first aspect, a semiconductor laser is provided. The semiconductor laser comprises: a substrate; a ridge waveguide disposed on the substrate and extending along a first direction of the substrate; a grating disposed on top of the ridge waveguide; wherein the grating comprises a first region and a second region periodically arranged along the first direction, the first region comprises a semiconductor material, the second region comprises an insulating dielectric material, and the refractive index of the insulating dielectric material is greater than the refractive index of the semiconductor material.

[0006] In this implementation, a grating is arranged on the top of a ridge waveguide, and a first region and a second region are arranged periodically in the grating, wherein the first region includes a semiconductor material, and the second region includes an insulating dielectric material, and the refractive index of the insulating dielectric material is greater than the refractive index of the semiconductor material. In this way, when the semiconductor laser is working, the working current can be injected from the first region instead of the second region, thereby forming a surface inversion gain coupling grating on the top of the ridge waveguide. The inversion gain coupling grating adjusts the phase distribution of light by introducing a phase shift, corrects the wavefront distortion of light, such as the wavefront distortion caused by the chirp effect, thereby reducing the chirp problem of the semiconductor laser. In addition, the inversion gain coupling grating is only epitaxially extended once during the formation process, thereby improving the yield of the semiconductor laser and effectively reducing the cost of the semiconductor laser.

[0007] In some possible implementations, the ridge waveguide includes a plurality of sub-waveguides arranged along the first direction, and the plurality of sub-waveguides are separated by insulating dielectric materials.

[0008] In some possible implementations, the sub-waveguides correspond to the first region of the grating one by one, and the insulating dielectric material between the plurality of sub-waveguides is integrally formed with the second region of the grating.

[0009] In some possible implementations, the base includes a substrate and an active layer disposed on the substrate. The active layer can provide support for amplification, modulation and stability of optical signals and improve light coupling efficiency.

[0010] In some possible implementations, the average refractive index of the active layer is greater than the refractive index of the insulating filling region, thereby further improving the performance of the semiconductor laser.

[0011] In some possible implementations, a first waveguide limiting layer is further disposed between the substrate and the active layer.

[0012] In some possible implementations, the semiconductor laser further includes a first electrode, which is disposed on the grating, and a projection of the grating on the substrate at least covers a portion of a projection of the first electrode on the substrate.

[0013] In some possible implementations, the semiconductor laser further includes a second electrode, and the second electrode is disposed on a side of the substrate away from the ridge waveguide.

[0014] In some possible implementations, the substrate includes a first surface and a second surface opposite to the first surface, and the extension direction of the first surface and the extension direction of the second surface are both perpendicular to the first direction of the substrate; the semiconductor laser also includes: a high-reflective dielectric film layer, and the high-reflective dielectric film layer covers the first surface of the substrate. By providing a high-reflective dielectric film layer in the semiconductor laser, the output power and performance of the semiconductor laser can be effectively enhanced, and the light utilization efficiency can be improved.

[0015] In some possible implementations, the semiconductor laser further includes: an anti-reflection dielectric film layer, the anti-reflection dielectric film layer covering the second surface of the substrate. Providing the anti-reflection dielectric film layer in the semiconductor laser can change the refraction and interference of light to reduce reflection, thereby improving transmittance and performance of the semiconductor laser.

[0016] In a second aspect, a method for manufacturing a semiconductor laser is provided, comprising: forming a substrate; forming a stacked ridge waveguide and a grating on the substrate, wherein the ridge waveguide extends along a first direction of the substrate; the grating comprises a first region and a second region periodically arranged along the first direction, the first region comprises a semiconductor material, the second region comprises an insulating dielectric material, and the refractive index of the insulating dielectric material is greater than the refractive index of the semiconductor material.

[0017] In some possible implementations, forming a stacked ridge waveguide and a grating on the substrate includes: forming a waveguide layer on the substrate;

[0018] An ohmic contact layer is formed on the waveguide layer; the waveguide layer and the ohmic contact layer are periodically etched to form periodically arranged openings on the waveguide layer and the ohmic contact layer, and the openings penetrate the waveguide layer and the ohmic contact layer; an insulating dielectric material is deposited in the openings to form a stacked ridge waveguide and a grating, wherein the ridge waveguide includes a plurality of sub-waveguides, and the plurality of sub-waveguides are separated by the insulating dielectric material.

[0019] In some possible implementations, forming the base includes: forming a substrate; and forming an active layer on the substrate.

[0020] In some possible implementations, before forming the active layer, forming the base further includes: forming a first waveguide confinement layer on the substrate.

[0021] In some possible implementations, forming the substrate further includes: forming a second waveguide limiting layer on the active layer.

[0022] In some possible implementations, the formation method further includes: depositing a first metal material on the grating to form a first electrode, and a projection of the grating on the substrate covers a projection of the first electrode on the substrate.

[0023] In some possible implementations, the formation method further includes: thinning the substrate; and depositing a second metal material on a side of the substrate away from the ridge waveguide to form a second electrode.

[0024] Among them, the technical effects brought about by any possible implementation method of the second aspect and the third aspect can refer to the technical effects brought about by different implementation methods of the above-mentioned first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic diagram of the structure of a semiconductor laser provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of a process for manufacturing a semiconductor laser provided in an embodiment of the present application;

[0028] Figure 3-Figure 16 This is a schematic diagram of the structures of various stages in the manufacturing process of the semiconductor laser provided in the embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0030] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0031] Additionally, for ease of description, spatially relative terms such as "bottom," "below," "below," "above," "above," etc. may be used herein to describe the relationship of one component or feature to another component, or function as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

[0032] Fiber-to-the-home gigabit passive optical networks (GPON) are the mainstream mode of broadband access networks. However, with the increasing demand for high-bitrate services such as high-definition video and high-performance edge computing from the user side in recent years, GPON networking can no longer meet the requirements for the scale development of high-bandwidth services in the future. In order to meet people's growing demand for transmission rate, the International Telecommunication Union-World Telecommunication Standards Conference (ITU-T) has successively announced the relevant specifications of 10G asymmetric passive optical networks (XG-PON) and 10G symmetric passive optical networks (XGS-PON). Compared with the GPON networking mode, the transmission rate of the downlink of XG(S)-PON has increased from the original 2.5Gb / s to 10Gb / s. At the same time, in order to be compatible with the previous transmission wavelengths, XG(S)-PON newly stipulates 1577nm in the L band as the central wavelength of its downlink. Compared with the semiconductor laser with a central wavelength of 1490nm, the light emitted by the semiconductor laser with a central wavelength of 1577nm has a larger dispersion in ordinary single-mode (G652) optical fiber, which in turn puts forward the requirement of low chirp for semiconductor lasers.

[0033] Semiconductor lasers are divided into electro-absorption modulated lasers (EML) and direct modulated lasers (DML).

[0034] The working principle of the directly modulated laser DML is: by injecting current into the semiconductor material, photons can be generated and amplified to form lasers. When the current changes, the light intensity of the laser output will also change accordingly. This directly modulated laser has the advantages of simple structure, high energy efficiency, and high output power, but the refractive index of the active area will change during the current modulation process, causing the phase of the light to be modulated, which in turn causes frequency chirp. The frequency chirp will have an increasingly greater impact as the modulation rate increases, resulting in limited transmission distance.

[0035] In order to improve the frequency chirp problem in the directly modulated laser DML, the following two methods can be used. The first method is to reduce the instantaneous chirp of the device by reducing the extinction ratio when performing signal modulation, but reducing the extinction ratio will affect other performances of the directly modulated laser, such as increasing the bit error rate, thereby causing the performance of the directly modulated laser to deteriorate. For this reason, a narrowband filter can be connected to the directly modulated laser, so that the adiabatic chirp effect can be used to reduce the signal amplitude of the "0" level to improve the extinction ratio, while ensuring that the extinction ratio meets the requirements, and reducing the chirp problem of the directly modulated laser; the second method is to adopt some chirp management technologies to reduce the chirp of the DML, such as pre-chirping technology based on digital signal processing chips, chirp-managed lasers, etc. However, both of the above methods will increase the complexity, size and cost of the directly modulated laser.

[0036] Electroabsorption modulated lasers include lasers and electroabsorption modulators (EAMs). Electroabsorption modulators are devices that achieve modulation by changing the absorption properties of materials through applied voltage. When voltage is applied to the electroabsorption modulator, it changes the optical band gap of the absorbing material, thereby controlling the output light intensity of the laser.

[0037] However, the electro-absorption modulated laser has a complex structure, and the laser and the electro-absorption modulator need to be designed and optimized separately. At the same time, the reflection at the output end face of the electro-absorption modulator will cause serious crosstalk between the laser and the electro-absorption modulator, resulting in a complex integration process. Therefore, the electro-absorption modulated laser has the problems of low reliability and low yield, which will make the price of the electro-absorption modulated laser very expensive. In addition, the inherent insertion loss of the electro-absorption modulated laser will cause its output optical power to be very low, which is difficult to meet the requirements of the XG(S)-PON system for light sources specified by ITU-T. Therefore, in actual applications, it is necessary to improve the sensitivity performance of the receiver in the link, or integrate a semiconductor optical amplifier to meet the specified power budget, which will further increase the cost of the XG(S)-PON system (optical line terminal).

[0038] In addition, whether it is a directly modulated laser or an electro-absorption modulated laser, before making a grating, it is necessary to first epitaxially grow semiconductor materials on the substrate to form a base (primary epitaxy); after the base is made, at least one more epitaxy is performed to form a grating (secondary epitaxy), and the grating is generated by controlling the growth conditions of the material and the formation of the periodic structure. This epitaxy needs to be precisely controlled to obtain the required grating parameters, such as period, depth, and refractive index difference; after the epitaxy is completed, other subsequent processes are required to produce the corresponding semiconductor laser. The epitaxy process consumes a lot of raw materials, and the equipment is expensive, so this process is relatively costly. Moreover, since the heating effect of the epitaxy will cause the grating to deform, in order to ensure the quality of the grating, more stringent process requirements need to be put forward for the secondary epitaxy, and the production cost of the secondary epitaxy is higher than that of the primary epitaxy. Therefore, the high production cost.

[0039] Therefore, an embodiment of the present application also provides a semiconductor laser. Figure 1 A schematic structural diagram of a semiconductor laser provided in an embodiment of the present application is shown, the semiconductor laser comprising: a substrate 100, a ridge waveguide 210 and a grating 220, the ridge waveguide 210 being arranged on the substrate 100 and extending along a first direction of the substrate 100; the grating 220 being arranged on top of the ridge waveguide 210, wherein the grating 220 comprises a first region 221 and a second region 222 periodically arranged along the first direction, the first region 221 comprising a semiconductor material, the second region 222 comprising an insulating dielectric material, and the refractive index of the insulating dielectric material being greater than the refractive index of the semiconductor material.

[0040] In a specific example, if Figure 2As shown, forming the above-mentioned semiconductor laser includes: S10: forming a substrate 100; S20: forming a stacked ridge waveguide 210 and a grating 220 on the substrate 100, wherein the ridge waveguide 210 extends along a first direction of the substrate 100; the grating 220 includes a first region 221 and a second region 222 periodically arranged along the first direction, the first region 221 includes a semiconductor material, and the second region 222 includes an insulating dielectric material, and the refractive index of the insulating dielectric material is greater than the refractive index of the semiconductor material.

[0041] In this embodiment, the grating 220 is arranged on the top of the ridge waveguide, and a first region 221 and a second region 222 are arranged periodically in the grating 220, wherein the first region 221 includes a semiconductor material, and the second region 222 includes an insulating dielectric material, and the refractive index of the insulating dielectric material is greater than the refractive index of the semiconductor material. In this way, when the semiconductor laser is working, the working current can be injected from the first region 221 instead of from the second region 222, thereby forming a surface inverted gain coupling grating on the top of the ridge waveguide 210. The inverted gain coupling grating is introduced by Phase shift is used to adjust the phase distribution of light and correct the wavefront distortion of light, such as the wavefront distortion caused by the chirp effect, thereby reducing the chirp problem of semiconductor lasers and laying the foundation for the application of DFB-DML in XG(S)-PON systems. In addition, the refractive index of the insulating dielectric material filled in the second region can be adjusted according to actual needs, which increases the process tolerance of semiconductor laser preparation and thus improves the yield of semiconductor lasers. In addition, the inverted gain-coupled grating is only epitaxially extended once during the formation process, effectively reducing the cost of semiconductor lasers.

[0042] The following takes the AlGaInAs / InP surface inverse gain coupled DFB-DML semiconductor laser with a wavelength of 1577nm as an example to illustrate the manufacturing process of the semiconductor laser and the device structure formed in the manufacturing process.

[0043] S10: forming a substrate 100. This step further includes:

[0044] S11: forming a substrate 101.

[0045] like Figure 3 As shown, the semiconductor laser includes a substrate 101. Exemplarily, the substrate 101 is a single-layer structure. For example, the substrate 101 is a heavily doped n-type InP substrate 101. Alternatively, exemplary, the substrate 101 is a multi-layer structure. For example, a buffer layer is further formed on the heavily doped n-type InP substrate 101, and the buffer layer can be an n-type InP buffer layer with a thickness of 500 nm and a doping concentration of 1.5×10 18 cm -3 .

[0046] S12 : forming a first waveguide confinement layer 102 on the substrate 101 .

[0047] like Figure 4 As shown, the semiconductor laser further includes a first waveguide limiting layer 102 formed on the substrate 101. Exemplarily, the first waveguide limiting layer 102 is a multi-layer structure, for example, the first waveguide limiting layer 102 is a three-layer structure, that is, the first waveguide limiting layer 102 is sequentially composed of: a first sub-waveguide limiting layer, a second sub-waveguide limiting layer and a third sub-waveguide limiting layer from bottom to top. The thickness of the first sub-waveguide limiting layer can be 10 nm, the fluorescence wavelength is 968 nm-841 nm, and the doping concentration of aluminum gallium indium arsenide (AlGaInAs) is 1.5×10 18 cm -3 The thickness of the second sub-waveguide limiting layer can be 40 nm, the fluorescence wavelength is 841 nm, and the doping concentration of aluminum indium arsenide (AlInAs) is 1.5×10 18 cm -3 The thickness of the third sub-waveguide limiting layer can be 50nm, the fluorescence wavelength is 841nm-1200nm, and the doping concentration of AlGaInAs is 0.5×10 18 cm -3 It is understandable that in other optional examples, the first waveguide limiting layer 102 may also be a single-layer structure. When the number of layers of the first waveguide limiting layer 102 changes, the component ratio of each sub-waveguide limiting layer in the first waveguide limiting layer 102 should also change accordingly.

[0048] S13 : forming an active layer 103 on the first waveguide confinement layer 102 .

[0049] like Figure 5 As shown, the semiconductor laser also includes an active layer 103 formed on the first waveguide limiting layer 102. The active layer 103 can provide support for the amplification, modulation and stability of the optical signal and improve the coupling efficiency of the light. Exemplarily, the active layer 103 is composed of quantum wells and potential barriers, wherein the quantum wells and potential barriers are preferably composed of compressive strain quantum wells and tensile strain potential barriers, and the quantum well material is indium gallium arsenic phosphide multiple quantum wells, or aluminum gallium indium arsenic multiple quantum wells, or aluminum gallium arsenic multiple quantum wells. Exemplarily, the active layer 103 includes 6 well layers and 7 barrier layers, wherein: the well width is 6nm, non-doped, ~1.3% compressive strain, and the light fluorescence wavelength is 1803nm; the barrier width is 6nm, non-doped, ~0.5% tensile strain, and the light fluorescence wavelength is 1299nm.

[0050] S14 : forming a second waveguide confinement layer 104 on the active layer 103 .

[0051] like Figure 6As shown, the semiconductor laser further includes a second waveguide limiting layer 104 formed on the active layer 103. Exemplarily, the second waveguide limiting layer 104 is a multi-layer structure, for example, the second waveguide limiting layer 104 is a four-layer structure, that is, the second waveguide limiting layer 104 is sequentially composed of: a fourth sub-waveguide limiting layer, a fifth sub-waveguide limiting layer, a sixth sub-waveguide limiting layer and a seventh sub-waveguide limiting layer from bottom to top. The thickness of the fourth sub-waveguide limiting layer can be 50 nm, the fluorescence wavelength is 1200 nm-841 nm, and the doping concentration of AlGaInAs is 0.3×10 18 cm -3 The thickness of the fifth sub-waveguide limiting layer can be 30 nm, the fluorescence wavelength is 841 nm, and the doping concentration of AlInAs is 0.5×10 18 cm -3 The thickness of the limiting stop layer of the sixth sub-waveguide 211 can be 10 nm, the fluorescence wavelength is 841 nm-968 nm, and the doping concentration of AlGaInAs is 0.5×10 18 cm -3 ); The fluorescence wavelength of the seventh sub-waveguide confinement layer is 1100nm, and the doping concentration of p-type InGaAsP is 0.5×10 18 cm -3 It is understandable that in other optional examples, the second waveguide limiting layer 104 may also be a single-layer structure. When the number of layers of the second waveguide limiting layer 104 changes, the component ratio of each sub-waveguide limiting layer in the second waveguide limiting layer 104 should also change accordingly.

[0052] It can be understood that the first waveguide limiting layer 102 , the active layer 103 , and the second waveguide limiting layer 104 can be formed simultaneously through a single epitaxial process, thereby reducing the manufacturing cost of the semiconductor laser.

[0053] S20: forming a stacked ridge waveguide 210 and a grating 220 on a substrate. This step further includes:

[0054] like Figure 7 As shown, S21: forming a waveguide layer 105 on the substrate. Exemplarily, the thickness of the waveguide layer 105 can be 1750 nm, and the gradient doping concentration is 0.5×10 18 cm -3 -2×10 18 cm -3 .

[0055] like Figure 8 As shown, S22 : forming an ohmic contact layer 106 on the waveguide layer 105 .

[0056] Exemplarily, the ohmic contact layer 106 is a multi-layer structure, for example, the ohmic contact layer 106 is a three-layer structure, that is, the ohmic contact layer 106 is sequentially composed of: a first sub-ohmic contact layer, a second sub-ohmic contact layer, and a third sub-ohmic contact layer from bottom to top. The first sub-ohmic contact layer may have a thickness of 25 nm, a fluorescence wavelength of 1250 nm, and a doping concentration of 3×10 18 cm -3 The thickness of the second sub-ohmic contact layer can be 25 nm, the fluorescence wavelength is 1500 nm, and the doping concentration of the heavily doped p-type InGaAsP is 3×10 18 cm -3 The thickness of the third sub-ohmic contact layer can be 150nm, the fluorescence wavelength is 1654nm, and the doping concentration of the heavily doped p-type InGaAs layer is 3×10 19 cm -3 .

[0057] like Fig. 9 As shown, S23: forming a dielectric layer 107 on the ohmic contact layer.

[0058] The dielectric layer 107 may be made of silicon oxide, silicon nitride, silicon oxynitride or other suitable materials, and is formed on the ohmic contact layer 106 by a deposition process, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), high density plasma chemical vapor deposition (HDPCVD), metal organic chemical vapor deposition (MOCVD) or plasma enhanced chemical vapor deposition (PECVD).

[0059] In some optional examples, before forming the dielectric layer 107, the formed semiconductor laser needs to be cleaned, for example, by sequentially cleaning the semiconductor laser with trichloroethylene, acetone, ethanol, and deionized water, and then baking at 120°C for 2 minutes to remove impurities remaining on the surface of the ohmic contact layer 106 to prevent the impurities from affecting the performance of the semiconductor laser.

[0060] like Fig.10 As shown, S24: forming a photoresist layer 108 on the dielectric layer 107, and patterning the photoresist layer 108 through a patterning process.

[0061] The patterning process includes a photolithography process and an etching process. The photolithography process includes photoresist coating (e.g., spin coating), soft baking, mask alignment, exposure, post-exposure baking, developing photoresist, rinsing and drying (e.g., hard baking). The etching process includes a dry etching process or a wet etching process. The grating pattern and the ridge waveguide 210 pattern can be made on the photoresist layer 108 by the etching process. Wherein, the grating 220 can be a first-order or high-order grating. Exemplarily, when the grating 220 is a first-order grating, the period range of the grating 220 can be 230-250nm, the duty cycle of the grating 220 can be 0.5-0.6, and the width of the grating 220 can be 1um-3um, and the corresponding ridge waveguide width 1.5um-5um high-order grating period range and duty cycle can be adjusted according to actual conditions, and the embodiment of the present application is not limited.

[0062] S25: Use the patterned photoresist layer 108 as a mask to pattern the dielectric layer 107. For example, a dry etching process can be used to pattern the dielectric layer 107, and the dry etching process includes using a fluorine-based etchant gas, such as SF6, CxFy, NF3, or a combination thereof. After forming the patterned dielectric layer 107, the patterned photoresist layer 108 should be removed.

[0063] S26 : using the patterned dielectric layer 107 as a mask to pattern the waveguide layer 105 and the ohmic contact layer 106 .

[0064] In this embodiment, see Fig.11 The schematic diagram of the structure of the semiconductor laser is shown in FIG. Fig.11 The second one is Fig.11 Middle (a) sectional view on AA' plane; Fig.11 Among them, (three) is Fig.11 (a) is a cross-sectional view on the BB' plane. By transferring the grating pattern and the ridge waveguide 210 pattern from the dielectric layer 107 to the waveguide layer 105 and the ohmic contact layer 106, a plurality of openings 223 penetrating the waveguide layer 105 and the ohmic contact layer 106 are formed. The plurality of openings 223 divide the waveguide layer 105 into a plurality of sub-waveguides 211, and the plurality of sub-waveguides 211 are arranged along the first direction of the substrate 100, and adjacent sub-waveguides 211 are separated by the openings 223. The unetched ohmic contact layer 106 constitutes the first region 221 of the grating 220.

[0065] In an optional example, a wet etching process or a dry etching process can be used to form openings in the waveguide layer 105 and the ohmic contact layer 106. For example, a wet etching process can be used to use a phosphoric acid and hydrobromic acid etching solution with a configuration ratio of 1:1. After standing for 5 minutes at 45°C, the semiconductor laser is placed in the etching solution for etching for 4-8 minutes. Since the etching rate ratio of the third sub-ohmic contact layer and the waveguide layer 105 is different, when the waveguide layer 105 and the ohmic contact layer 106 are patterned by the wet etching process, the third sub-ohmic contact layer can be used as an etching stop layer. The dry etching process can be used by inductively coupled plasma etching (ICP), with Cl2, CH4, H2, and Ar as reaction gases, to etch the ohmic contact layer 106 and the waveguide layer 105, and the end point monitoring function of the instrument is used to stop the etching in time, and the patterned dielectric layer 107 is removed after the waveguide layer 105 and the ohmic contact layer 106 are patterned.

[0066] S27: depositing an insulating dielectric material in the opening to form the second region 222 of the grating 220. For example, the insulating dielectric material may be silicon (Si) or silicon oxynitride.

[0067] In this embodiment, see Fig.12 The schematic diagram of the structure of the semiconductor laser is shown in FIG. Fig.12 The second one is Fig.12 Middle (a) sectional view on AA' plane; Fig.12 Among them, (three) is Fig.12 (a) is a cross-sectional view on the BB' plane. By depositing an insulating dielectric material in the opening 223, the plurality of sub-waveguides 211 are separated by the insulating dielectric material, and a plurality of second regions 222 are formed in the grating 220. The first region 221 and the second region 222 of the grating 220 are periodically arranged along the first direction of the substrate 100. The refractive index of the insulating dielectric material in the second region 222 is greater than the refractive index of the semiconductor material in the first region 221. In this way, when the semiconductor laser is working, the working current can be injected from the first region 221 of the grating 220 instead of from the second region 222 is injected, thereby forming a surface inverted gain coupling grating on the top of the waveguide. The inverted gain coupling grating adjusts the phase distribution of light by introducing a phase shift, corrects the wavefront distortion of light, such as the wavefront distortion caused by the chirp effect, thereby reducing the chirp problem of the semiconductor laser, and the refractive index of the insulating dielectric material filled in the second region can be adjusted according to actual needs, thereby increasing the process tolerance of semiconductor laser preparation, thereby improving the yield of semiconductor lasers; in addition, the inverted gain coupling grating is only epitaxially extended once during the formation process, effectively reducing the cost of semiconductor lasers.

[0068] In some optional embodiments, the average refractive index of the active layer 103 is greater than the refractive index of the insulating dielectric material filled in the second region 222 of the grating 220 , so as to improve the performance of the semiconductor laser.

[0069] It should be noted that, in some optional examples, after depositing the insulating dielectric material, the surface of the grating 220 may be planarized, for example, by using a self-aligned photolithography method to form a photoresist mask on the surface of the grating 220, and using an etcher to etch away the protruding insulating dielectric material on the surface of the grating 220, and remove the residual photoresist; if there are still protrusions on the surface of the grating 220, the previous step may be repeated to completely planarize the surface of the grating 220, or to planarize it to a degree that meets the requirements.

[0070] It should be noted that the number of ridge waveguides 210 can be adjusted according to actual applications and is not limited to one ridge waveguide 210. In some other optional embodiments, arrayed ridge waveguides 210 are formed on the substrate, and a grating 220 is formed on each ridge waveguide 210.

[0071] S30 : forming an insulating layer 230 on the substrate 100 .

[0072] See also Fig.13 The schematic diagram of the structure of the semiconductor laser shown in the figure shows that an insulating layer 230 is formed on the substrate 100 by a deposition process. For example, the insulating layer 230 uses a photosensitive BCB material. The insulating layer 230 covers the grating 220 and the ridge waveguide 210, and then the insulating layer 230 is thinned until the upper surface of the insulating layer 230 is flush with the top of the grating 220, that is, the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220. Finally, it is ensured that the top of the grating 220 is observed under an optical microscope to expose a uniform white bright color of the InGaAs material without any interference color of the insulating layer 230.

[0073] It should be noted that when there are multiple ridge waveguides 210 on the substrate 100, a gap is provided in the insulating layer 230 between adjacent ridge waveguides 210. Exemplarily, the width of the gap is 50 μm, and the length of the gap is generally in the range of 100-1000 μm. The gap serves as a cutting path for dissociating the semiconductor laser, dissociating the substrate 100 into multiple semiconductor lasers including a single ridge waveguide 210.

[0074] It can be understood that the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220, which includes absolute equality and approximate equality, wherein the approximately equal is within an acceptable deviation range, for example, the height difference between the two can be less than or equal to 100 nm, and the spacing between the ridge waveguide 210 and the insulating layer 230 can be less than or equal to 1 μm.

[0075] See also Fig.14 The schematic diagram of the structure of the semiconductor laser is shown in FIG. Fig.14 The second one is Fig.14 (a) is a cross-sectional view on the AA' plane, S40: a first metal material is deposited on the grating 220 to form a first electrode 240, and the projection of the grating 220 on the substrate at least covers a portion of the projection of the first electrode 240 on the substrate. Exemplarily, the first electrode 240 is a P-type electrode, the first metal material is Ti, Pt, Au or other metal materials, and the thickness of the first electrode 240 is 20-400nm. The width of the first electrode 240 is equal to the width of the ridge waveguide 210. In some optional embodiments, an electrode pad 241 and a connecting structure 242 connecting the first electrode 240 to the electrode pad can also be formed while forming the first electrode 240. The electrode pad 241 can be a circular pad with a diameter of 100μm, and the distance between the circular pad and the ridge waveguide 210 can be less than or equal to 20μm, and the connecting structure 242 can be a rectangular structure with a width of 20μm.

[0076] It can be understood that the width of the first electrode 240 being equal to the width of the ridge waveguide 210 includes being absolutely equal and being approximately equal. Within the acceptable deviation range of being approximately equal, for example, the width difference between the two may be less than or equal to 1 μm.

[0077] S41: thinning the side of the substrate 100 away from the ridge waveguide 210, and depositing a second metal material on the side of the substrate away from the ridge waveguide 210 to form a second electrode 250. For example, see Fig.15 In the structural schematic diagram of the semiconductor laser shown, the second electrode 250 is an N-type electrode. Accordingly, the material of the second electrode 250 is Ti or Au, and the thickness of the second electrode 250 is 30-500 nm.

[0078] S50: forming a high reflective dielectric film layer 261 covering the first surface of the substrate 100, wherein the extension direction of the first surface is perpendicular to the first direction of the substrate 100; illustratively, the reflectivity of the high reflective dielectric film layer 261 ranges from 95% to 99.99%. By providing the high reflective dielectric film layer 261 in the semiconductor laser, the output power and performance of the semiconductor laser can be effectively enhanced, and the light utilization efficiency can be improved.

[0079] S51: forming an anti-reflection dielectric film layer 262 covering the second surface of the substrate, the second surface of the substrate 100 is arranged opposite to the first surface of the substrate 100, and the extension direction of the second surface is also perpendicular to the first direction of the substrate 100. The anti-reflection dielectric film layer 262 is arranged in the semiconductor laser, which can change the refraction and interference of light to reduce reflection, thereby improving the transmittance and performance of the semiconductor laser. Exemplarily, the reflectivity of the anti-reflection dielectric film layer 262 ranges from 0.01% to 0.5%.

[0080] The following describes various parts of the semiconductor laser by taking an InGaAsP / InP surface inverse gain coupled DFB-DML semiconductor laser with a wavelength of 1577 nm as an example.

[0081] The semiconductor laser includes a substrate 100 . Specifically, the substrate 100 includes a substrate 101 , a first waveguide limiting layer 102 , an active layer 103 and a second waveguide limiting layer 104 .

[0082] The substrate 101 may be a single-layer structure. For example, the substrate 101 is a heavily doped n-type InP substrate 101. Alternatively, the substrate 101 may be a multi-layer structure. For example, a buffer layer is formed on the heavily doped n-type InP substrate 101. The buffer layer may be an n-type InP buffer layer with a thickness of 500 nm and a doping concentration of 1.5×10 18 cm -3 .

[0083] The first waveguide limiting layer 102 may be a multi-layer structure, for example, the first waveguide limiting layer 102 is a three-layer structure, that is, the first waveguide limiting layer 102 is composed of: a first sub-waveguide limiting layer, a second sub-waveguide limiting layer and a third sub-waveguide limiting layer from bottom to top. The thickness of the first sub-waveguide limiting layer may be 10 nm, the fluorescence wavelength may be 968 nm-841 nm, and the doping concentration of indium gallium arsenic phosphide (InGaAsP) may be 1.5×10 18 cm -3 The thickness of the second sub-waveguide limiting layer can be 40 nm, the fluorescence wavelength is 841 nm, and the doping concentration of indium gallium arsenide (InGaAs) is 1.5×10 18 cm -3 The thickness of the third sub-waveguide limiting layer can be 50nm, the fluorescence wavelength is 841nm-1200nm, and the doping concentration of InGaAsP is 0.5×10 18 cm -3 It is understandable that in other optional examples, the first waveguide limiting layer 102 may also be a single-layer structure. When the number of layers of the first waveguide limiting layer 102 changes, the component ratio of each sub-waveguide limiting layer in the first waveguide limiting layer 102 should also change accordingly.

[0084] The active layer 103 may be composed of quantum wells and potential barriers, wherein the quantum wells and potential barriers are preferably composed of compressive strain quantum wells and tensile strain potential barriers, and the quantum well materials are indium gallium arsenic phosphide multiple quantum wells, or aluminum gallium indium arsenic multiple quantum wells, or aluminum gallium arsenic multiple quantum wells. Exemplarily, the active layer 103 includes 6 well layers and 7 barrier layers, wherein: the well width is 6nm, non-doped, ~1.3% compressive strain, and the optical fluorescence wavelength is 1803nm; the barrier width is 6nm, non-doped, ~0.5% tensile strain, and the optical fluorescence wavelength is 1299nm.

[0085] The second waveguide limiting layer 104 may be a multi-layer structure, for example, the second waveguide limiting layer 104 is a four-layer structure, that is, the second waveguide limiting layer 104 is sequentially composed of the fourth sub-waveguide limiting layer, the fifth sub-waveguide limiting layer, the sixth sub-waveguide limiting layer and the seventh sub-waveguide limiting layer from bottom to top. The thickness of the fourth sub-waveguide limiting layer may be 50 nm, the fluorescence wavelength may be 841-1200 nm, and the doping concentration of InGaAsP may be 0.3×10 18 cm -3 The thickness of the fifth sub-waveguide limiting layer can be 30 nm, the fluorescence wavelength is 841 nm-968 nm, and the doping concentration of InGaAs is 0.5×10 18 cm -3 The thickness of the limiting stop layer of the sixth sub-waveguide 211 can be 10 nm, the fluorescence wavelength is 841 nm-968 nm, and the doping concentration of InGaAsP is 0.5×10 18 cm -3 ); The fluorescence wavelength of the seventh sub-waveguide confinement layer is 1100nm, and the doping concentration of p-type InGaAsP is 0.5×10 18 cm -3 It is understandable that in other optional examples, the second waveguide limiting layer 104 may also be a single-layer structure. When the number of layers of the second waveguide limiting layer 104 changes, the component ratio of each sub-waveguide limiting layer in the second waveguide limiting layer 104 should also change accordingly.

[0086] The semiconductor laser is further provided with a ridge waveguide 210 and a grating 220 stacked on the substrate 100. Specifically:

[0087] The ridge waveguide 210 includes a plurality of sub-waveguides 211 arranged along a first direction of the substrate 100, and adjacent sub-waveguides 211 are separated by insulating dielectric materials. The thickness of each sub-waveguide 211 in the ridge waveguide 210 may be 1750 nm, and the gradient doping concentration in each sub-waveguide 211 is 0.5×10 18 cm -3 -2×10 18 cm -3 .

[0088] The grating 220 includes a first region 221 and a second region 222. The first region 221 of the grating 220 is a multi-layer structure. For example, the first region 221 of the grating 220 is a three-layer structure, that is, the first region 221 of the grating 220 is, from bottom to top, a patterned first sub-ohmic contact layer, a patterned second sub-ohmic contact layer, and a patterned third sub-ohmic contact layer. The patterned first sub-ohmic contact layer may have a thickness of 25 nm, a fluorescence wavelength of 1250 nm, and a doping concentration of 3×1018 cm -3 The thickness of the patterned second sub-ohmic contact layer can be 25 nm, the fluorescence wavelength is 1500 nm, and the doping concentration of the heavily doped p-type InGaAsP is 3×10 18 cm -3 The thickness of the patterned third sub-ohmic contact layer can be 150 nm, the fluorescence wavelength is 1654 nm, and the doping concentration of the heavily doped p-type InGaAs layer is 3×10 19 cm -3 .

[0089] The second region 222 of the grating 220 is provided with an insulating dielectric material, and the insulating dielectric material is integrally formed with the insulating dielectric material between the sub-waveguide 211. The first region 221 and the second region 222 of the grating 220 are periodically arranged along the first direction of the substrate 100. The refractive index of the insulating dielectric material in the second region 222 is greater than the refractive index of the semiconductor material in the first region 221. In this way, when the semiconductor laser is working, the working current can be injected from the first region 221 of the grating 220 instead of being injected from the second region 222, thereby forming a surface inversion gain coupling grating on the top of the waveguide. The inversion gain coupling grating adjusts the phase distribution of light by introducing a phase shift, corrects the wavefront distortion of light, such as correcting the wavefront distortion caused by the chirp effect, thereby reducing the chirp problem of the semiconductor laser; and the refractive index of the insulating dielectric material filled in the second region can be adjusted according to actual needs, thereby increasing the process tolerance of the semiconductor laser preparation, thereby improving the yield of the semiconductor laser; in addition, the inversion gain coupling grating is only epitaxially extended once during the formation process, effectively reducing the cost of the semiconductor laser.

[0090] It should be noted that the number of ridge waveguides 210 can be adjusted according to actual applications and is not limited to one ridge waveguide 210. In some other optional embodiments, arrayed ridge waveguides 210 are formed on the substrate, and a grating 220 is formed on each ridge waveguide 210.

[0091] In some optional embodiments, the semiconductor laser further includes an insulating layer 230 disposed on the substrate 100. For example, the insulating layer 230 is made of a photosensitive BCB material. The upper surface of the insulating layer 230 is flush with the top of the grating 220, that is, the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220.

[0092] It should be noted that when there are multiple ridge waveguides 210 on the substrate 100, a gap is provided in the insulating layer 230 between adjacent ridge waveguides 210. Exemplarily, the width of the gap is 50 μm, and the length of the gap is generally in the range of 100-1000 μm. The gap serves as a cutting path for separating the semiconductor lasers, separating the substrate into multiple semiconductor lasers including a single ridge waveguide 210.

[0093] It can be understood that the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220, which can be equal to either absolutely or approximately. The approximately equal thickness is within an acceptable deviation range, for example, the height difference between the two can be less than or equal to 100 nm, and the spacing between the ridge waveguide 210 and the insulating layer 230 can be less than or equal to 1 μm.

[0094] In some optional embodiments, the semiconductor laser further includes a first electrode 240 disposed on the grating 220. Exemplarily, the first electrode 240 is a P-type electrode, the first metal material is Ti, Pt, Au or other metal materials, and the thickness of the first electrode 240 is 20-400 nm. The first electrode 240 is composed of a thin strip at the top of the ridge waveguide (width ≤ ridge waveguide width + 1 μm), an electrode pad (a circle with a diameter of 100 μm, and a spacing of ≤20 μm from the ridge waveguide), and a connecting portion of the two (width 20 μm).

[0095] In some optional embodiments, the semiconductor laser further includes a second electrode 250 disposed on a side of the substrate away from the ridge waveguide 210. Exemplarily, the second electrode 250 is an N-type electrode, and accordingly, the material of the second electrode 250 is Ti or Au, and the thickness of the second electrode 250 is 30-500 nm.

[0096] In some optional embodiments, the semiconductor laser further includes a high reflective dielectric film layer 261 disposed on the first surface of the substrate, and the extension direction of the first surface is perpendicular to the first direction of the substrate; illustratively, the reflectivity of the high reflective dielectric film layer 261 ranges from 95% to 99.99%.

[0097] In some optional embodiments, the semiconductor laser further includes an anti-reflection dielectric film layer 262 disposed on the second surface of the substrate 100, the second surface of the substrate 100 is disposed opposite to the first surface of the substrate 100, and the extension direction of the second surface is also perpendicular to the first direction of the substrate 100. Exemplarily, the reflectivity of the anti-reflection dielectric film layer 262 ranges from 0.01% to 0.5%.

[0098] The following describes various parts of the semiconductor laser by taking an AlGaInAs / InP surface inverse gain coupled DFB-DML semiconductor laser with a wavelength of 1550nm as an example.

[0099] The semiconductor laser includes a substrate 100 . Specifically, the substrate 100 includes a substrate 101 , a first waveguide limiting layer 102 , an active layer 103 and a second waveguide limiting layer 104 .

[0100] The substrate 101 may be a single-layer structure. For example, the substrate 101 is a heavily doped n-type InP substrate 101. Alternatively, the substrate 101 may be a multi-layer structure. For example, a buffer layer is formed on the heavily doped n-type InP substrate 101. The buffer layer may be an n-type InP buffer layer with a thickness of 1500 nm and a doping concentration of 0.5×10 18 cm -3 .

[0101] The first waveguide limiting layer 102 may be a single-layer structure, for example, the first waveguide limiting layer 102 may be formed of AlGaInAs material, the thickness of the first waveguide limiting layer 102 may be 125nm, the fluorescence wavelength is 900nm-1000nm, and it is undoped. It can be understood that in other optional examples, the first waveguide limiting layer 102 may also be a multi-layer structure, and when the number of layers of the first waveguide limiting layer 102 changes, the component ratio of each sub-waveguide limiting layer in the first waveguide limiting layer 102 should also change accordingly.

[0102] The active layer 103 may be composed of quantum wells and potential barriers, wherein the quantum wells and potential barriers are preferably composed of compressive strain quantum wells and tensile strain potential barriers, and the quantum well materials are indium gallium arsenic phosphide multiple quantum wells, or aluminum gallium indium arsenic multiple quantum wells, or aluminum gallium arsenic multiple quantum wells. Exemplarily, the active layer 103 includes 3 well layers and 4 barrier layers, wherein: the well width is 5.5nm, non-doped, -1.3% compressive strain, and the optical fluorescence wavelength is 1850nm; the barrier width is 10nm, non-doped, ~0.5% tensile strain, and the optical fluorescence wavelength is 1100nm.

[0103] The second waveguide limiting layer 104 may be a single-layer structure, for example, the second waveguide limiting layer may be formed of AlGaInAs material, the thickness of the second waveguide limiting layer 104 may be 110nm, the fluorescence wavelength is 900nm-1000nm, and it is undoped. It can be understood that in other optional examples, the second waveguide limiting layer 104 may also be a multi-layer structure, and when the number of layers of the second waveguide limiting layer 104 changes, the component ratio of each sub-waveguide limiting layer in the second waveguide limiting layer 104 should also change accordingly.

[0104] The semiconductor laser is further provided with a ridge waveguide 210 and a grating 220 stacked on the substrate 100. Specifically:

[0105] The ridge waveguide 210 includes a plurality of sub-waveguides 211 arranged along a first direction of the substrate 100, and adjacent sub-waveguides 211 are separated by insulating dielectric materials. The thickness of each sub-waveguide 211 in the ridge waveguide 210 can be 1900 nm, and the gradient doping concentration in each sub-waveguide 211 is 0.5×10 18 cm -3 –2.5×10 18 cm -3 .

[0106] The grating 220 includes a first region 221 and a second region 222. The first region 221 of the grating 220 is a multi-layer structure. For example, the first region 221 of the grating 220 is a three-layer structure, that is, the first region 221 of the grating 220 is, from bottom to top, a patterned first sub-ohmic contact layer, a patterned second sub-ohmic contact layer, and a patterned third sub-ohmic contact layer. The patterned first sub-ohmic contact layer may have a thickness of 25 nm, a fluorescence wavelength of 1100 nm, and a doping concentration of 3×10 18 cm -3 The thickness of the patterned second sub-ohmic contact layer can be 50 nm, the fluorescence wavelength is 1300 nm, and the doping concentration of the heavily doped p-type InGaAsP is 5×10 18 cm -3 The thickness of the patterned third sub-ohmic contact layer can be 150 nm, the fluorescence wavelength is 1654 nm, and the doping concentration of the heavily doped p-type InGaAs layer is 2.5×10 19 cm -3 .

[0107] The second region 222 of the grating 220 is provided with an insulating dielectric material, and the insulating dielectric material is integrally formed with the insulating dielectric material between the sub-waveguide 211. The first region 221 and the second region 222 of the grating 220 are periodically arranged along the first direction of the substrate 100. The refractive index of the insulating dielectric material in the second region 222 is greater than the refractive index of the semiconductor material in the first region 221. In this way, when the semiconductor laser is working, the working current can be injected from the first region 221 of the grating 220 instead of being injected from the second region 222, thereby forming a surface inversion gain coupling grating on the top of the waveguide. The inversion gain coupling grating adjusts the phase distribution of light by introducing a phase shift, corrects the wavefront distortion of light, such as correcting the wavefront distortion caused by the chirp effect, thereby reducing the chirp problem of the semiconductor laser; and the refractive index of the insulating dielectric material filled in the second region can be adjusted according to actual needs, thereby increasing the process tolerance of the semiconductor laser preparation, thereby improving the yield of the semiconductor laser; in addition, the inversion gain coupling grating is only epitaxially extended once during the formation process, effectively reducing the cost of the semiconductor laser.

[0108] It should be noted that the number of ridge waveguides 210 can be adjusted according to actual applications and is not limited to one ridge waveguide 210. In some other optional embodiments, arrayed ridge waveguides 210 are formed on the substrate, and a grating 220 is formed on each ridge waveguide 210.

[0109] In some optional embodiments, the semiconductor laser further includes an insulating layer 230 disposed on the substrate 100. For example, the insulating layer 230 is made of a photosensitive BCB material. The upper surface of the insulating layer 230 is flush with the top of the grating 220, that is, the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220.

[0110] It should be noted that when there are multiple ridge waveguides 210 on the substrate 100, a gap is provided in the insulating layer 230 between adjacent ridge waveguides 210. Exemplarily, the width of the gap is 50 μm, and the length of the gap is generally in the range of 100-1000 μm. The gap serves as a cutting path for separating the semiconductor lasers, separating the substrate into multiple semiconductor lasers including a single ridge waveguide 210.

[0111] It can be understood that the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220, which can be equal to either absolutely or approximately. The approximately equal thickness is within an acceptable deviation range, for example, the height difference between the two can be less than or equal to 100 nm, and the spacing between the ridge waveguide 210 and the insulating layer 230 can be less than or equal to 1 μm.

[0112] In some optional embodiments, the semiconductor laser further includes a first electrode 240 disposed on the grating 220. Exemplarily, the first electrode 240 is a P-type electrode, the first metal material is Ti, Pt, Au or other metal materials, and the thickness of the first electrode 240 is 20-400 nm. The first electrode 240 is composed of a thin strip at the top of the ridge waveguide (width ≤ ridge waveguide width + 1 μm), an electrode pad (a circle with a diameter of 100 μm, and a spacing of ≤20 μm from the ridge waveguide), and a connecting portion of the two (width 20 μm).

[0113] In some optional embodiments, the semiconductor laser further includes a second electrode 250 disposed on a side of the substrate away from the ridge waveguide 210. Exemplarily, the second electrode 250 is an N-type electrode, and accordingly, the material of the second electrode 250 is Ti or Au, and the thickness of the second electrode 250 is 30-500 nm.

[0114] In some optional embodiments, the semiconductor laser further includes a high reflective dielectric film layer 261 disposed on the first surface of the substrate, and the extension direction of the first surface is perpendicular to the first direction of the substrate; illustratively, the reflectivity of the high reflective dielectric film layer 261 ranges from 95% to 99.99%.

[0115] In some optional embodiments, the semiconductor laser further includes an anti-reflection dielectric film layer 262 disposed on the second surface of the substrate, the second surface of the substrate 100 is disposed opposite to the first surface of the substrate 100, and the extension direction of the second surface is also perpendicular to the first direction of the substrate 100. Exemplarily, the reflectivity of the anti-reflection dielectric film layer 262 ranges from 0.01% to 0.5%.

[0116] The following describes various parts of the semiconductor laser by taking an InGaAsP / InP surface inverse gain coupled DFB-DML semiconductor laser with a wavelength of 1550nm as an example.

[0117] The semiconductor laser includes a substrate 100 . Specifically, the substrate 100 includes a substrate 101 , a first waveguide limiting layer 102 , an active layer 103 and a second waveguide limiting layer 104 .

[0118] The substrate 101 may be a single-layer structure. For example, the substrate 101 is a heavily doped n-type InP substrate 101. Alternatively, the substrate 101 may be a multi-layer structure. For example, a buffer layer is formed on the heavily doped n-type InP substrate 101. The buffer layer may be an n-type InP buffer layer with a thickness of 1500 nm and a doping concentration of 0.5×10 18 cm -3 .

[0119] The first waveguide limiting layer 102 may be a single-layer structure, for example, the first waveguide limiting layer 102 may be formed of InGaAsP material, the thickness of the first waveguide limiting layer 102 may be 125nm, the fluorescence wavelength is 900nm-1000nm, and it is undoped. It can be understood that in other optional examples, the first waveguide limiting layer 102 may also be a multi-layer structure, and when the number of layers of the first waveguide limiting layer 102 changes, the component ratio of each sub-waveguide limiting layer in the first waveguide limiting layer 102 should also change accordingly.

[0120] The active layer 103 may be composed of quantum wells and potential barriers, wherein the quantum wells and potential barriers are preferably composed of compressive strain quantum wells and tensile strain potential barriers, and the quantum well materials are indium gallium arsenic phosphide multiple quantum wells, or aluminum gallium indium arsenic multiple quantum wells, or aluminum gallium arsenic multiple quantum wells. Exemplarily, the active layer 103 includes 3 well layers and 4 barrier layers, wherein: the well width is 5.5nm, non-doped, -1.3% compressive strain, and the optical fluorescence wavelength is 1850nm; the barrier width is 10nm, non-doped, ~0.5% tensile strain, and the optical fluorescence wavelength is 1100nm.

[0121] The second waveguide limiting layer 104 may be a single-layer structure, for example, the second waveguide limiting layer may be formed of InGaAsP material, the thickness of the second waveguide limiting layer 104 may be 110 nm, the fluorescence wavelength is 900 nm-1000 nm, and it is undoped. It is understood that in other optional examples, the second waveguide limiting layer 104 may also be a multi-layer structure, and when the number of layers of the second waveguide limiting layer 104 changes, the component ratio of each sub-waveguide limiting layer in the second waveguide limiting layer 104 should also change accordingly.

[0122] The semiconductor laser is further provided with a ridge waveguide 210 and a grating 220 stacked on the substrate 100. Specifically:

[0123] The ridge waveguide 210 includes a plurality of sub-waveguides 211 arranged along a first direction of the substrate 100, and adjacent sub-waveguides 211 are separated by insulating dielectric materials. The thickness of each sub-waveguide 211 in the ridge waveguide 210 can be 1900 nm, and the gradient doping concentration in each sub-waveguide 211 is 0.5×10 18 cm -3 –2.5×10 18 cm -3 .

[0124] The grating 220 includes a first region 221 and a second region 222. The first region 221 of the grating 220 is a multi-layer structure. For example, the first region 221 of the grating 220 is a three-layer structure, that is, the first region 221 of the grating 220 is, from bottom to top, a patterned first sub-ohmic contact layer, a patterned second sub-ohmic contact layer, and a patterned third sub-ohmic contact layer. The patterned first sub-ohmic contact layer may have a thickness of 25 nm, a fluorescence wavelength of 1100 nm, and a doping concentration of 3×10 18 cm -3 The thickness of the patterned second sub-ohmic contact layer can be 50 nm, the fluorescence wavelength is 1300 nm, and the doping concentration of the heavily doped p-type InGaAsP is 5×10 18 cm -3The thickness of the patterned third sub-ohmic contact layer can be 150 nm, the fluorescence wavelength is 1654 nm, and the doping concentration of the heavily doped p-type InGaAs layer is 2.5×10 19 cm -3 .

[0125] The second region 222 of the grating 220 is provided with an insulating dielectric material, and the insulating dielectric material is integrally formed with the insulating dielectric material between the sub-waveguide 211. The first region 221 and the second region 222 of the grating 220 are periodically arranged along the first direction of the substrate 100. The refractive index of the insulating dielectric material in the second region 222 is greater than the refractive index of the semiconductor material in the first region 221. In this way, when the semiconductor laser is working, the working current can be injected from the first region 221 of the grating 220 instead of being injected from the second region 222, thereby forming a surface inversion gain coupling grating on the top of the waveguide. The inversion gain coupling grating adjusts the phase distribution of light by introducing a phase shift, corrects the wavefront distortion of light, such as correcting the wavefront distortion caused by the chirp effect, thereby reducing the chirp problem of the semiconductor laser; and the refractive index of the insulating dielectric material filled in the second region can be adjusted according to actual needs, thereby increasing the process tolerance of the semiconductor laser preparation, thereby improving the yield of the semiconductor laser; in addition, the inversion gain coupling grating is only epitaxially extended once during the formation process, effectively reducing the cost of the semiconductor laser.

[0126] It should be noted that the number of ridge waveguides 210 can be adjusted according to actual applications and is not limited to one ridge waveguide 210. In some other optional embodiments, arrayed ridge waveguides 210 are formed on the substrate, and a grating 220 is formed on each ridge waveguide 210.

[0127] In some optional embodiments, the semiconductor laser further includes an insulating layer 230 disposed on the substrate 100. For example, the insulating layer 230 is made of a photosensitive BCB material. The upper surface of the insulating layer 230 is flush with the top of the grating 220, that is, the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220.

[0128] It should be noted that when there are multiple ridge waveguides 210 on the substrate 100, a gap is provided in the insulating layer 230 between adjacent ridge waveguides 210. Exemplarily, the width of the gap is 50 μm, and the length of the gap is generally in the range of 100-1000 μm. The gap serves as a cutting path for separating the semiconductor lasers, separating the substrate into multiple semiconductor lasers including a single ridge waveguide 210.

[0129] It can be understood that the thickness of the insulating layer 230 is equal to the total thickness of the ridge waveguide 210 and the grating 220, which can be equal to either absolutely or approximately. The approximately equal thickness is within an acceptable deviation range, for example, the height difference between the two can be less than or equal to 100 nm, and the spacing between the ridge waveguide 210 and the insulating layer 230 can be less than or equal to 1 μm.

[0130] In some optional embodiments, the semiconductor laser further includes a first electrode 240 disposed on the grating 220. Exemplarily, the first electrode 240 is a P-type electrode, the first metal material is Ti, Pt, Au or other metal materials, and the thickness of the first electrode 240 is 20-400 nm. The first electrode 240 is composed of a thin strip at the top of the ridge waveguide (width ≤ ridge waveguide width + 1 μm), an electrode pad (a circle with a diameter of 100 μm, and a spacing of ≤20 μm from the ridge waveguide), and a connecting portion of the two (width 20 μm).

[0131] In some optional embodiments, the semiconductor laser further includes a second electrode 250 disposed on a side of the substrate away from the ridge waveguide 210. Exemplarily, the second electrode 250 is an N-type electrode, and accordingly, the material of the second electrode 250 is Ti or Au, and the thickness of the second electrode 250 is 30-500 nm.

[0132] In some optional embodiments, such as Fig.16 As shown, the semiconductor laser further includes a high reflective dielectric film layer 261 disposed on the first surface of the substrate, and the extension direction of the first surface is perpendicular to the first direction of the substrate; illustratively, the reflectivity of the high reflective dielectric film layer 261 ranges from 95% to 99.99%.

[0133] In some optional embodiments, such as Fig.16 As shown, the semiconductor laser further includes an anti-reflection dielectric film layer 262 disposed on the second surface of the substrate 100. The second surface of the substrate 100 is disposed opposite to the first surface of the substrate 100, and the extension direction of the second surface is also perpendicular to the first direction of the substrate 100. Exemplarily, the reflectivity of the anti-reflection dielectric film layer 262 ranges from 0.01% to 0.5%.

[0134] It can be understood that the above examples are only examples listed for a better understanding of the technical solutions of the embodiments of the present application, and are not the only limitation to the embodiments of the present application. The materials for forming the first waveguide limiting layer, the active layer, and the second waveguide limiting layer of the semiconductor laser can be selected according to actual conditions to adjust the emission wavelength of the semiconductor laser. The materials for the first waveguide limiting layer, the active layer, and the second waveguide limiting layer can be group III-IV compounds.

[0135] Another embodiment of the present application also provides a non-transitory computer-readable storage medium for use with a computer, the computer having software for creating and manufacturing the above-mentioned semiconductor laser, and one or more computer-readable data structures are stored on the computer-readable storage medium, and the one or more computer-readable data structures have control data for manufacturing the semiconductor laser provided in any one of the diagrams provided above, such as photoresist layer data.

[0136] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the 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 semiconductor laser, characterized in that: include: substrate; A ridge waveguide, wherein the ridge waveguide is disposed on the substrate and extends along a first direction of the substrate; A grating is arranged on the top of the ridge waveguide, wherein the grating includes a first region and a second region periodically arranged along the first direction, the first region includes a semiconductor material, the second region includes an insulating dielectric material, and the refractive index of the insulating dielectric material is greater than the refractive index of the semiconductor material.

2. The semiconductor laser according to claim 1, characterized in that The ridge waveguide includes a plurality of sub-waveguides arranged along the first direction, and the plurality of sub-waveguides are separated by insulating dielectric materials.

3. The semiconductor laser according to claim 2, characterized in that The sub-waveguides correspond to the first regions of the grating one by one, and the insulating dielectric material between the sub-waveguides is integrally formed with the second region of the grating.

4. The semiconductor laser according to any one of claims 1 to 3, characterized in that: The base includes a substrate and an active layer disposed on the substrate.

5. The semiconductor laser according to claim 4, characterized in that The average refractive index of the active layer is greater than the refractive index of the insulating medium material.

6. The semiconductor laser according to claim 4 or 5, characterized in that: A first waveguide limiting layer is also arranged between the substrate and the active layer.

7. The semiconductor laser according to any one of claims 4 to 6, characterized in that: A second waveguide limiting layer is arranged on the active layer.

8. The semiconductor laser according to any one of claims 1 to 7, characterized in that: The semiconductor laser further includes a first electrode, which is disposed on the grating, and a projection of the grating on the substrate at least covers a portion of a projection of the first electrode on the substrate.

9. The semiconductor laser according to any one of claims 1 to 8, characterized in that: The semiconductor laser further includes a second electrode, which is disposed on a side of the substrate away from the ridge waveguide.

10. The semiconductor laser according to any one of claims 1 to 9, characterized in that: The substrate comprises a first surface and a second surface opposite to the first surface, and an extension direction of the first surface and an extension direction of the second surface are both perpendicular to the first direction of the substrate; The semiconductor laser further comprises: A high reflective dielectric film layer covers the first surface of the substrate.

11. The semiconductor laser according to claim 10, characterized in that The semiconductor laser further comprises: An anti-reflection dielectric film layer covers the second surface of the substrate.

12. A method for manufacturing a semiconductor laser, characterized in that: include: forming a base; A stacked ridge waveguide and a grating are formed on the substrate, wherein the ridge waveguide extends along a first direction of the substrate; the grating includes a first region and a second region periodically arranged along the first direction, the first region includes a semiconductor material, and the second region includes an insulating dielectric material, and the refractive index of the insulating dielectric material is greater than the refractive index of the semiconductor material.

13. The method according to claim 12, characterized in that Forming a stacked ridge waveguide and a grating on the substrate comprises: forming a waveguide layer on the substrate; forming an ohmic contact layer on the waveguide layer; Periodically etching the waveguide layer and the ohmic contact layer to form periodically arranged openings on the waveguide layer and the ohmic contact layer, wherein the openings penetrate the waveguide layer and the ohmic contact layer; An insulating dielectric material is deposited in the opening to form the stacked ridge waveguide and the grating, wherein the ridge waveguide includes a plurality of sub-waveguides, and the plurality of sub-waveguides are separated by insulating dielectric material.

14. The method according to claim 12 or 13, characterized in that Forming the substrate includes: forming a substrate; An active layer is formed on the substrate.

15. The method according to claim 14, characterized in that Before forming the active layer, forming the substrate further comprises: A first waveguide confinement layer is formed on the substrate.

16. The method according to claim 14 or 15, characterized in that Forming the substrate also includes: A second waveguide confinement layer is formed on the active layer.

17. The method according to any one of claims 12 to 16, characterized in that: The production method further comprises: A first metal material is deposited on the grating to form a first electrode, and a projection of the grating on the substrate covers a projection of the first electrode on the substrate.

18. The method according to any one of claims 12 to 17, characterized in that: The production method further comprises: thinning the substrate; A second metal material is deposited on a side of the substrate away from the ridge waveguide to form a second electrode.

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