阅读说明：本技术 一种大功率半导体光放大器增益介质的制备方法 (Preparation method of gain medium of high-power semiconductor optical amplifier ) 是由 陈嘉健 陈亦凡 魏玲 于 2020-12-30 设计创作，主要内容包括：一种大功率半导体光放大器增益介质的制备方法,包括：提供基板；在所述基板上依次生长缓冲层、n电极层、下限制层、有源层和上限制层、p电极层；沉积p型金属制作p型电极；制作增益介质串联图形；刻蚀制作脊波导结构至n电极层,形成增益介质；沉积n型金属制作电极。为了更好地控制光场采用深刻蚀工艺,刻蚀波导结构时贯穿有源区(层),如刻蚀贯穿上限制层和有源层,刻蚀至部分下限制层。其中,分子束外延是外延制膜方法,是在适当的衬底与合适的条件下,沿衬底材料晶轴方向逐层生长薄膜的方法。使用的衬底温度低,膜层生长速率慢,束流强度易于精确控制,膜层组分和掺杂浓度可随源的变化而迅速调整。(A preparation method of a gain medium of a high-power semiconductor optical amplifier comprises the following steps: providing a substrate; growing a buffer layer, an n electrode layer, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer on the substrate in sequence; depositing p-type metal to manufacture a p-type electrode; manufacturing a gain medium series graph; etching the ridge waveguide structure to the n electrode layer to form a gain medium; and depositing n-type metal to manufacture the electrode. In order to better control the optical field, a deep etching process is adopted, and the waveguide structure is etched to penetrate through the active region (layer), for example, the waveguide structure is etched to penetrate through the upper limiting layer and the active layer and is etched to reach part of the lower limiting layer. The molecular beam epitaxy is an epitaxial film-making method, which is a method for growing a thin film layer by layer along the crystal axis direction of a substrate material under a proper substrate and proper conditions. The used substrate has low temperature, the film layer has slow growth rate, the beam intensity is easy to control accurately, and the film layer components and the doping concentration can be adjusted rapidly along with the source change.)

1. A preparation method of a gain medium of a high-power semiconductor optical amplifier is characterized by comprising the following steps:

providing a substrate;

growing a buffer layer, an n electrode layer, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer on the substrate in sequence;

depositing p-type metal to manufacture a p-type electrode;

manufacturing a gain medium series graph;

etching the ridge waveguide structure to the n electrode layer to form a gain medium;

and depositing n-type metal to manufacture the electrode.

2. The method of claim 1, wherein the active layer is made of a quantum dot material.

3. The method for preparing a gain medium of a high power semiconductor optical amplifier according to claim 1, wherein the substrate is made of gallium arsenide.

4. The method for preparing a gain medium of a high power semiconductor optical amplifier according to claim 1, wherein the step of etching the ridge waveguide structure to the n electrode layer to form the gain medium further comprises: and depositing a p electrode layer on the upper limiting layer before etching, depositing an n electrode on the surface after etching, and sequentially forming a silicon dioxide dielectric film and a gold contact electrode on the surface of the etched ridge waveguide.

5. The method for preparing a gain medium of a high power semiconductor optical amplifier as claimed in claim 1, wherein the process of sequentially growing a buffer layer, an n-electrode layer, a lower confinement layer, an active layer, an upper confinement layer and a p-electrode layer on the substrate further comprises: and sequentially growing a buffer layer, an n electrode layer, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer on the substrate through molecular beam epitaxy.

6. The method for preparing a gain medium of a high power semiconductor optical amplifier as claimed in claim 1, wherein the process of sequentially growing a buffer layer, an n-electrode layer, a lower confinement layer, an active layer, an upper confinement layer and a p-electrode layer on the substrate further comprises: and sequentially growing a buffer layer, an n electrode layer, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer on the substrate through metal organic compound chemical vapor deposition epitaxy.

7. The method for preparing a gain medium of a high power semiconductor optical amplifier according to claim 1, wherein the process of making the gain medium series pattern specifically comprises: and manufacturing a series pattern of the MMI gain medium by photoetching.

8. The method for preparing a gain medium of a high power semiconductor optical amplifier as claimed in claim 1, wherein the process of depositing n-type metal to make the electrode specifically comprises: and depositing n-type metal to manufacture an n surface electrode or a back electrode.

[ technical field ] A method for producing a semiconductor device

The invention relates to the field of photoelectron, in particular to a preparation method of a gain medium of a high-power semiconductor optical amplifier.

[ background of the invention ]

An optical amplifier is a subsystem product capable of amplifying optical signals in an optical fiber communication system. The principle of an optical amplifier is basically based on stimulated emission of laser light, and amplification is achieved by converting the energy of pump light into the energy of signal light. The successful development and industrialization of optical amplifiers are very important achievements in optical fiber communication technology, which greatly promote the development of optical multiplexing technology, optical soliton communication and all-optical networks. There are two main types of optical amplifiers, semiconductor optical amplifier (semiconductor optical amplifier) and optical fiber amplifier. Semiconductor amplifiers are generally referred to as traveling wave optical amplifiers and operate on a similar principle to semiconductor lasers. The working bandwidth is very wide, but the gain amplitude is slightly smaller, the manufacturing difficulty is higher, and the optical amplifier is practical, but the popularization and the use have more technical restrictions.

In the field of optical communication and optical sensing, amplification or gain supply of light in a link is often required, an Erbium Doped Fiber (EDFA) can be used for solving the problem of insufficient gain in a communication C-band, and a semiconductor optical amplifier is required for solving the problem in a communication O-band. At present, most of commercial semiconductor optical amplifiers adopt quantum well structures. InAs (indium arsenide) quantum dot materials have the characteristic of large gain bandwidth compared with traditional quantum well materials, and therefore the InAs quantum dot materials are quite suitable for manufacturing semiconductor optical amplifiers and Reflective Semiconductor Optical Amplifiers (RSOA). However, quantum dot materials have the disadvantage of insufficient gain compared to conventional quantum well materials. Accordingly, there is a need for improvements in the art that overcome the deficiencies in the prior art.

[ summary of the invention ]

The invention aims to provide a preparation method of a high-power semiconductor optical amplifier gain medium with wide spectrum and high power.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a gain medium of a high-power semiconductor optical amplifier comprises the following steps:

providing a substrate;

growing a buffer layer, an n electrode layer, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer on the substrate in sequence;

depositing p-type metal to manufacture a p-type electrode;

manufacturing a gain medium series graph;

etching the ridge waveguide structure to the n electrode layer to form a gain medium;

and depositing n-type metal to manufacture the electrode.

In one embodiment, the active layer is comprised of quantum dot material.

In one embodiment, the substrate is made of gallium arsenide.

In one embodiment, the etching process for fabricating the ridge waveguide structure to the n-electrode layer and forming the gain medium further includes: and depositing a p electrode layer on the upper limiting layer before etching, depositing an n electrode on the surface after etching, and sequentially forming a silicon dioxide dielectric film and a gold contact electrode on the surface of the etched ridge waveguide.

In one embodiment, the process of sequentially growing the buffer layer, the n-electrode layer, the lower confinement layer, the active layer, the upper confinement layer and the p-electrode layer on the substrate further includes: and sequentially growing a buffer layer, an n electrode layer, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer on the substrate through molecular beam epitaxy.

In one embodiment, the process of sequentially growing the buffer layer, the n-electrode layer, the lower confinement layer, the active layer, the upper confinement layer and the p-electrode layer on the substrate further includes: and sequentially growing a buffer layer, an n electrode layer, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer on the substrate through metal organic compound chemical vapor deposition epitaxy.

In one embodiment, the process of manufacturing the gain medium series pattern specifically includes: and manufacturing a series pattern of the MMI gain medium by photoetching.

In one embodiment, the process of depositing the n-type metal to fabricate the electrode specifically includes: and depositing n-type metal to manufacture an n surface electrode or a back electrode.

Compared with the prior art, the invention has the following beneficial effects: in order to better control the optical field, a deep etching process is adopted, and the waveguide structure is etched to penetrate through the active region (layer), for example, the waveguide structure is etched to penetrate through the upper limiting layer and the active layer and is etched to reach part of the lower limiting layer. The manufacturing process specifically comprises the steps of Molecular Beam Epitaxy (MBE) growth, p electrode deposition, deep etching of a waveguide structure, passivation windowing of a silicon dioxide dielectric film, gold electrode electroplating, substrate thinning, n electrode manufacturing, cleavage coating and the like. The molecular beam epitaxy is an epitaxial film-making method, which is a method for growing a thin film layer by layer along the crystal axis direction of a substrate material under a proper substrate and proper conditions. The used substrate has low temperature, the film layer has slow growth rate, the beam intensity is easy to control accurately, and the film layer components and the doping concentration can be adjusted rapidly along with the source change. Due to the fact that the quantum dot non-uniform broadening characteristic brings spectral gain which is wider than that of a quantum well structure, the quantum dot material structure is used for achieving a semiconductor optical amplifier which is wider in gain, smaller in fluctuation and larger in power compared with a traditional quantum well scheme.

[ description of the drawings ]

FIG. 1 is a schematic cross-sectional view of a gain medium of a high-power semiconductor optical amplifier according to the present invention;

FIG. 2 is a schematic cross-sectional view of a high-power semiconductor optical amplifier gain medium after etching;

FIG. 3 is a schematic diagram of a high power semiconductor optical amplifier of the present invention;

FIG. 4 is a schematic flow chart of a method for preparing a gain medium of a high-power semiconductor optical amplifier according to the present invention;

FIG. 5 is a schematic diagram of the distribution of the optical field of the gain medium of the high power semiconductor optical amplifier of the present invention;

FIG. 6 is a schematic diagram of the output power test of the gain medium of the high-power semiconductor optical amplifier according to the present invention;

FIG. 7 is a schematic diagram of the temperature stability test of the gain medium of the high-power semiconductor optical amplifier according to the present invention.

[ detailed description ] embodiments

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

In the description of the present application, it is to be understood that the terms "central", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations and positional relationships based on the orientations and positional relationships shown in the drawings, and are used for convenience in describing and simplifying the description, but do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the scope of the present application. Furthermore, the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of the feature. In the description of the invention of the present application, "a plurality" means two or more unless otherwise specified.

Throughout the description of the present application, it is to be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art through specific situations.

FIG. 1 is a schematic cross-sectional view of a gain medium of a high-power semiconductor optical amplifier according to the present invention; FIG. 2 is a schematic cross-sectional view of a high-power semiconductor optical amplifier gain medium after etching; FIG. 3 is a schematic diagram of a high power semiconductor optical amplifier of the present invention; FIG. 4 is a schematic flow chart of a method for preparing a gain medium of a high-power semiconductor optical amplifier according to the present invention; FIG. 5 is a schematic diagram of the distribution of the optical field of the gain medium of the high power semiconductor optical amplifier of the present invention; FIG. 6 is a schematic diagram of the output power test of the gain medium of the high-power semiconductor optical amplifier according to the present invention; FIG. 7 is a schematic diagram of the temperature stability test of the gain medium of the high-power semiconductor optical amplifier according to the present invention.

Referring to fig. 4, the present invention discloses a method for preparing a gain medium of a high-power semiconductor optical amplifier, including: step 10, providing a substrate; step 20, growing a buffer layer, an n electrode layer 12, a lower limiting layer, an active layer, an upper limiting layer and a p electrode layer 15 on a substrate in sequence; step 30, depositing p-type metal to manufacture a p-type electrode; step 40, manufacturing a gain medium series graph; step 50, etching the ridge waveguide structure to the n electrode layer 12 to form a gain medium; and step 60, depositing n-type metal to manufacture an electrode.

In one embodiment, a method for preparing a gain medium of a high-power semiconductor optical amplifier comprises the following steps: providing a substrate 11, wherein the substrate 11 is made of gallium arsenide material; sequentially growing a buffer layer, an n-electrode layer 12, a lower limiting layer 13', an active layer 14, an upper limiting layer 13 and a p-electrode layer 15 on a substrate 11 by molecular beam epitaxy or MOCVD (metal organic chemical vapor deposition) epitaxial growth equipment; depositing p-type metal to manufacture a p-type electrode; manufacturing an MMI gain medium series connection graph through photoetching; etching to manufacture a ridge waveguide structure to the n electrode layer 12 to form the gain medium 10; and depositing n-type metal to manufacture an n surface electrode or a back electrode.

The fabrication process is similar to that of conventional ridge waveguide lasers, but a deep etch process may be used to etch through the active region (layer) while etching the waveguide structure in order to better control the optical field. E.g., etching through the upper confinement layer 13 and the active layer 14 to partially etch the lower confinement layer 13'. The manufacturing process specifically comprises the steps of Molecular Beam Epitaxy (MBE) growth, p electrode deposition, deep etching of a waveguide structure, passivation windowing of a silicon dioxide dielectric film, gold electrode electroplating, substrate thinning, n electrode manufacturing, cleavage coating and the like. The molecular beam epitaxy is an epitaxial film-making method and is also a special vacuum coating process. Epitaxy is a method for growing a thin film layer by layer along the crystal axis direction of a substrate material under a proper substrate and proper conditions: under the condition of ultrahigh vacuum, the molecular beam or atomic beam formed by heating vapour produced by furnace containing various required components and collimating by means of small hole is directly sprayed on the monocrystal substrate with proper temp., at the same time the molecular beam is controlled and scanned on the substrate, so that the molecules or atoms can be "grown" layer by layer according to crystal arrangement so as to form film on the substrate. The technology has the advantages that: the used substrate has low temperature, the film layer has slow growth rate, the beam intensity is easy to control accurately, and the film layer components and the doping concentration can be adjusted rapidly along with the source change.

In one embodiment, a buffer layer, an n-electrode layer 12, a lower confinement layer 13', an active layer 14, an upper confinement layer 13, and a p-electrode layer 15 are sequentially grown on a substrate 11, the active layer 14 being composed of a quantum dot material.

In one embodiment, the process of etching through the upper confinement layer 13, the active layer 14 and the lower confinement layer 13' to form the gain medium further comprises: and depositing a p electrode layer 15 on the upper limiting layer 13 before etching, depositing an n electrode on the surface after etching, and sequentially forming a silicon dioxide dielectric film and a gold contact electrode on the surface of the etched ridge waveguide. To form the metal electrode, it may be thinned at the bottom of the substrate 11. The n-electrode may also be formed by forming an n-metal electrode on the bottom of the substrate 11.

Referring to fig. 1 to 3, the present invention further discloses a high-power semiconductor optical amplifier, which includes a plurality of gain media 10 sequentially arranged along a light propagation direction, wherein the gain media 10 are used for amplifying signal light input to the gain media 10 or providing gain, especially in a communication O band. In the embodiment, the gain medium 10 includes a base plate 11, and a lower confinement layer 13', an active layer 14, and an upper confinement layer 13, which are sequentially stacked over the base plate 11 (substrate). The active layer 14 is composed of quantum dot material. The gain medium 10 is prepared by the preparation method of the gain medium of the high-power semiconductor optical amplifier.

Fig. 5 is a schematic diagram of optical field distribution of a gain medium of a high-power semiconductor optical amplifier in an embodiment of the present invention, and experiments show that an electroluminescence infrared photograph of an active MMI (multi-mode interference) quantum well device matches optical field distribution calculated by light wave propagation theory (BPM) simulation, which means that an active MMI structure has optical field distribution similar to that of a passive device with the same structure. Based on the principle, the waveguides entering and exiting the MMI have the same mode by designing the MMI waveguide structure. In the embodiment, a plurality of gain media 10 are sequentially arranged and connected one by one, and the optical field distribution of light before entering the gain media 10 or after leaving the gain media 10 is the same or similar, and the light is diffused after entering the gain media 10. The area of the MMI semiconductor optical amplifier designed according to the structure is larger than that of a traditional straight waveguide laser, so that the active MMI structure has lower resistance and higher gain area, and compared with the traditional SOA/RSOA, the manufactured semiconductor optical amplifier has higher output power and better temperature stability.

Quantum dots are an important low-dimensional semiconductor material, and the size of each of the three dimensions is not larger than twice the exciton bohr radius of the corresponding semiconductor material. Quantum dots are generally spherical or spheroidal, often with diameters between 2-20 nm. Common quantum dots are composed of IV, II-VI, IV-VI or III-V elements. Specific examples are silicon quantum dots, germanium quantum dots, cadmium sulfide quantum dots, cadmium selenide quantum dots, cadmium telluride quantum dots, zinc selenide quantum dots, lead sulfide quantum dots, lead selenide quantum dots, indium phosphide quantum dots, indium arsenide quantum dots, and the like. The quantum dot material in this embodiment is preferably indium gallium arsenide (InGaAs)/indium arsenide (InAs), and the active layer 14 is formed by the InGaAs/InAs material and the corresponding pad structure.

In one embodiment, the substrate 11 is a gallium arsenide substrate, and a molecular beam epitaxy technique or a vapor phase epitaxy technique is used to form a stacked structure on the substrate.

In one of the embodiments, several gain media 10 are connected in series with each other, forming an MMI cascade structure in which the output signal light of the previous gain medium 10 in the light propagation direction serves as the input signal light of the subsequent gain medium.

In one embodiment, the gain medium is a 1 × 1 multimode coherent structure (MMI). The mirror image characteristic of the input and output optical mode lengths can be realized by utilizing the MMI structure, and the single mode characteristic of the input and output light is ensured. Meanwhile, the range of the gain region is increased by utilizing the MMI region, so that the high-power output of the SOA device is realized.

In order to ensure higher output power and better temperature stability of the semiconductor optical amplifier, in one embodiment, the gain medium 10 has at least one, and may be cascaded in a plurality. The size of the gain medium 10 itself also affects the output power, and the power can be further increased by increasing the length and width of the individual gain media 10.

In one embodiment, the gain medium 10 is coated with an anti-reflection coating (AR). In one embodiment, the high power semiconductor optical amplifier is used to make a reflective semiconductor optical amplifier, and the gain medium 10 is coated with a reflective film (HR) and an anti-reflection film. Aiming at different use scenes, including application to a Semiconductor Optical Amplifier (SOA) and a Reflective Semiconductor Optical Amplifier (RSOA), different coating schemes are adopted, and the SOA is coated with an AR/AR film, and the RSOA is coated with an HR/AR film. Preferably, the reflective semiconductor optical amplifier adopts a straight waveguide HR and an extremely low reflection AR, so that the coupling is easy, and the reflectivity is reduced only by means of AR coating; or the front end bending waveguide HR/AR is coated, and the bending waveguide + AR has extremely low reflection (10e-5), but the bending waveguide is not easy to couple. The semiconductor optical amplifier adopts a front end bending waveguide AR/AR coating film, the bending waveguide + AR has extremely low reflection (10e-5), but the bending waveguide is not easy to couple; or slanted waveguide AR/AR coating, which is easy to fabricate and has very low reflectivity, but coupling can lose a portion of the optical power due to angle problems.

In order to protect the interlayer structure of the gain medium 10 and improve the stability of the gain medium 10, in one embodiment, an upper limiting layer 13 and a lower limiting layer 13' are respectively disposed between the p-electrode layer 15 and the n-electrode layer 12 and the active layer 14, and the upper and lower limiting layers may be made of AlGaAs (aluminum gallium arsenide).

In one embodiment, a buffer layer, an n-electrode layer 12, a lower limiting layer 13', an active layer 14, an upper limiting layer 13, and a p-electrode layer 15 are sequentially stacked over the substrate 11, and the upper limiting layer and the lower limiting layer are respectively disposed between the p-electrode layer 15 and the n-electrode layer 12 and the active layer 14.

In one embodiment, the upper confinement layer 13 and the lower confinement layer 13' are aluminum gallium arsenide (AlGaAs) layers, and the p-electrode layer 15 and the n-electrode layer 12 are gallium arsenide (GaAs) layers.

Referring to fig. 6 and 7, it is tested that the high-power semiconductor optical amplifier manufactured by the method of the present invention has better output power and temperature stability than the common or conventional structure.

The O-band SOA manufactured by the high-power semiconductor optical amplifier in the embodiment of the invention can be used for a data center, and the L-band is used for amplifying an optical signal transmitted for a long distance in telecommunication. The RSOA can be mixed and integrated with a passive PLC waveguide (planar optical waveguide) structure to manufacture a high-power narrow-linewidth tunable laser, or be used for manufacturing a laser array light source by a gain chip. Among them, narrow linewidth lasers can be used for applications such as coherent transmission, optical fiber sensing, etc. The laser array chip can be used for manufacturing a wavelength division multiplexing optical module.

Compared with the prior art, the invention has the following beneficial effects: in order to better control the optical field, a deep etching process is adopted, and the waveguide structure is etched to penetrate through the active region (layer), for example, the waveguide structure is etched to penetrate through the upper limiting layer and the active layer and is etched to reach part of the lower limiting layer. The manufacturing process specifically comprises the steps of Molecular Beam Epitaxy (MBE) growth, p electrode deposition, deep etching of a waveguide structure, passivation windowing of a silicon dioxide dielectric film, gold electrode electroplating, substrate thinning, n electrode manufacturing, cleavage coating and the like. The molecular beam epitaxy is an epitaxial film-making method, which is a method for growing a thin film layer by layer along the crystal axis direction of a substrate material under a proper substrate and proper conditions. The used substrate has low temperature, the film layer has slow growth rate, the beam intensity is easy to control accurately, and the film layer components and the doping concentration can be adjusted rapidly along with the source change. Due to the fact that the quantum dot non-uniform broadening characteristic brings spectral gain which is wider than that of a quantum well structure, the quantum dot material structure is used for achieving a semiconductor optical amplifier which is wider in gain, smaller in fluctuation and larger in power compared with a traditional quantum well scheme.

In light of the foregoing description of the preferred embodiments according to the present application, it is to be understood that various changes and modifications may be made without departing from the spirit and scope of the invention. The technical scope of the present application is not limited to the contents of the specification, and must be determined according to the scope of the claims.