CN116632651A - Silicon-based surface high-order grating laser and its preparation method - Google Patents

Abstract

The invention relates to the technical field of optoelectronic devices, in particular to a silicon-based surface high-order grating laser and a preparation method thereof, wherein the laser comprises the following components: the device comprises a substrate, an inverted ridge waveguide structure arranged on the substrate, an insulating layer arranged on the upper layer of the waveguide structure, and a filling layer filled between the waveguide structure and the insulating layer; the Bragg gratings are etched on the upper surface of the waveguide structure and the upper surface of the filling layer. According to the grating laser provided by the invention, the surface grating form is designed, so that the grating can be manufactured by adopting a common photoetching technology, secondary epitaxy is not needed, the manufacturing process is simple, the production is easy, and the yield of products is improved.

Description

Silicon-based surface high-order grating laser and its preparation method

technical field

The invention relates to the technical field of optoelectronic devices, in particular to a silicon-based surface high-order grating laser and a preparation method thereof.

Background technique

Microelectronics technology has developed rapidly in accordance with Moore's Law for decades, which has greatly changed the face of contemporary society. Now it is an information society, and the requirements for information processing capacity and transmission speed are increasing day by day. However, with the development of microelectronics processing technology, the current processing accuracy has reached several nanometers, getting closer to the size of atoms, almost reaching the physical limit, and complex quantum effects have to be considered, which makes the progress of process technology difficult. , it is difficult to meet the still growing communication demand. At this time, Opto-Electronic Integrated Circuit (OEIC) has attracted attention. As the carrier of information, light consumes less energy and is faster than electrons. It can also use advanced silicon processing technology to perform high-density integration and reduce mass production costs. It is a key technology to continue to increase the capacity and speed of information transmission.

Silicon-based photonic integration technology can use advanced microelectronic processing technology, and has high processing precision, high integration, and low mass production cost. Using silicon-based to prepare passive waveguide devices has incomparable advantages over III-V materials. However, because silicon is an indirect bandgap semiconductor, it is difficult to prepare active devices such as optical amplifiers and lasers. At present, most of the mass-produced semiconductor lasers are made of III-V materials. If you want to take advantage of the advantages of silicon-based passive devices and III-V active devices and integrate them together, the cost of packaging will be greatly increased. increase, so silicon-based lasers are very important for reducing the cost of photonic integration and realizing real silicon-based photonic integration.

The distributed feedback (Distributed Feedback, DFB) laser in the prior art uses a Bragg grating for optical feedback, so that the laser can get better feedback amplification at a specific wavelength. In the prior art, the grating is usually etched near the active layer. And it needs to be buried by secondary epitaxy, but this will increase the complexity of the process and reduce the yield and reliability of laser devices.

Contents of the invention

The invention provides a silicon-based surface high-order grating laser and a preparation method thereof, aiming to solve the technical problem that the existing laser structure increases the complexity of the process, resulting in a low yield.

In one aspect, the present invention provides a silicon-based surface high-order grating laser, comprising

Substrate;

an inverted ridge waveguide structure disposed over the substrate;

an insulating layer disposed on the upper layer of the waveguide structure;

providing a filling layer between the waveguide structure and the insulating layer;

Wherein, the upper surface of the waveguide structure and the upper surface of the filling layer are provided with Bragg gratings.

A silicon-based surface high-order grating laser provided according to the present invention also includes:

a patterned silicon dioxide layer disposed between the substrate and the waveguide structure;

a passivation layer disposed between the buried oxide layer and the filling layer;

a first electrode disposed on a lower layer of the substrate;

The second electrode is arranged on the upper layer of the insulating layer.

According to a silicon-based surface high-order grating laser provided by the present invention, the waveguide structure includes a buffer layer and a lower cladding layer on the buffer layer, a lower confinement layer, and a quantum well active Region and upper cladding layer respectively. According to a silicon-based surface high-order grating laser provided by the present invention, the distance from the lower surface of the lower respectively confinement layer to the substrate is smaller than the distance from the upper surface of the buried oxide layer to the substrate, in other words, the lower respectively confinement layer The lower end of is not higher than the upper end of the buried oxide layer.

According to a silicon-based surface high-order grating laser provided by the present invention, the characteristic size of the Bragg grating is greater than 1 μm, the period of the grating is greater than 5 μm, and the order of the Bragg grating is greater than 9.

According to a silicon-based surface high-order grating laser provided by the present invention, the groove width of the Bragg grating and the width of the unetched region between the grooves satisfy the following relationship:

Among them, d _s represents the width of the Bragg grating groove, n _s represents the effective refractive index of the Bragg grating groove, λ represents the Bragg wavelength corresponding to the Bragg grating, d _w represents the width of the unetched area between the grooves, and n _w represents the Bragg grating The effective refractive index of the unetched area;

Both p and q are positive integers, the period Λ=d _s +d _w of the Bragg grating, and the order m=p+q+1 of the Bragg grating.

According to a silicon-based surface high-order grating laser provided by the present invention, the groove depth of the Bragg grating is 0.5-0.7 microns, and the bottom of the groove of the Bragg grating is higher than the lower surface of the filling layer.

According to a silicon-based surface high-order grating laser provided by the present invention, the cavity length of the waveguide structure is 100-200 microns.

On the other hand, the present invention also provides a method for preparing a silicon-based surface high-order grating laser, including:

providing a substrate;

forming an inverted ridge waveguide structure on the upper surface of the substrate;

Filling the waveguide structure with a material that can be used for grating etching to form a filling layer; so that the waveguide structure and the filling layer together form a grating layer;

forming an insulating layer on the upper surface of the waveguide structure and the upper surface of the filling layer;

forming a first electrode on the lower surface of the substrate;

A second electrode is formed on the upper surface of the insulating layer.

According to a method for preparing a silicon-based surface high-order grating laser provided by the present invention, forming an inverted ridge waveguide structure on the upper surface of the substrate includes:

Etching a V-shaped groove on the upper surface of the substrate, and epitaxially forming a buffer layer in the V-shaped groove;

forming a lower cladding layer on the buffer layer;

forming a lower respective confinement layer on the upper layer of the lower cladding layer;

forming a quantum well active region on the lower confinement layer;

forming an upper confinement layer on the active region of the quantum well;

An upper cladding layer is formed on the upper respective confinement layer.

The silicon-based surface high-order grating laser provided by the present invention includes: a substrate, an inverted ridge waveguide structure arranged on the substrate, an insulating layer arranged on the upper layer of the waveguide structure, and an insulating layer arranged between the waveguide structure and the insulating layer The inter-filling layer; wherein, the upper surface of the waveguide structure and the upper surface of the filling layer are etched with Bragg gratings. According to the grating laser provided by the present invention, the form of the surface grating is designed, so that the grating can be made by common photolithography technology, no secondary epitaxy is needed, the manufacturing process is simple, easy to produce, and the yield of the product is improved.

Description of drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are the present invention. For some embodiments of the invention, those skilled in the art can also obtain other drawings based on these drawings without creative effort.

FIG. 1 is a schematic structural diagram of a silicon-based surface high-order grating laser provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an inverted ridge waveguide structure provided by an embodiment of the present invention;

Fig. 3 is one of the schematic diagrams of the Bragg grating structure provided in the embodiment of the present invention;

Fig. 4 is the second schematic diagram of the grating structure provided in the embodiment of the present invention;

5 is a schematic diagram of the output spectrum simulation results of the four-wavelength silicon-based high-order surface grating laser provided by the embodiment of the present invention;

6 is a flow chart of a method for fabricating a silicon-based surface high-order grating laser provided by an embodiment of the present invention;

FIG. 7 is a schematic flowchart of a method for generating a waveguide structure provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention , but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

In the embodiments of the present invention, words such as "first" and "second" are used to distinguish the same or similar items with basically the same function and effect, which are only for clearly describing the technical solutions of the embodiments of the present invention, and cannot be understood To indicate or imply relative importance or to imply the number of indicated technical features.

In the embodiments of the present invention, "multi-layer" means two or more layers, "at least one layer" means one or more layers, and "multiple" means two or more layers. , unless otherwise specifically defined.

In the embodiments of the present invention, the orientations or positional relationships indicated by the terms "upper", "lower", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or It should not be construed as limiting the invention by implying that a referenced device or element must have a particular orientation, be constructed, and operate in a particular orientation.

Because silicon is an indirect bandgap semiconductor, it is not suitable for the preparation of active devices, so the current mainstream is to combine III-V materials with silicon-based photonic integration, and use III-V groups to make active devices. At present, there are mainly two preparation methods of bonding (Bonding) and heteroepitaxy. Group III-V and silicon wafer epitaxy are also divided into direct bonding, metal bonding, and BCB (benzocyclobutene) bonding. Among them, direct bonding has very high requirements on the process environment, and metal bonding and BCB bonding will cause thermal stability to deteriorate because metal or BCB will be filled between the two devices. Direct epitaxy is the most direct method, but because the III-V group materials do not match the crystal lattice of the silicon substrate, the material grown by direct epitaxy has many defects and poor quality, and cannot be made into a laser.

In order to solve this problem, a very thick buffer layer can be grown on the silicon, and then the quantum dot laser can be grown, but because the current quantum dot growth is not uniform, and the thick buffer layer makes it difficult for the light emitted by the laser to be coupled into the silicon substrate. in the waveguide. There is another method called high aspect ratio confinement (Aspect Ratio Trapping, ART) technology, which grows III-V group materials in silicon dioxide trenches, which utilizes high silicon dioxide sidewall aspect ratios to epitaxial III- Defects generated when using group V materials are confined to the bottom of the trench, reducing the defect density of the epitaxial material at the top. Another method is the distributed feedback technology. The distributed feedback (Distributed Feedback, DFB) laser uses a Bragg grating for optical feedback, so that the laser can get better feedback amplification at a specific wavelength. The grating is usually etched near the active layer and Requires secondary epitaxy to bury it. However, the common problems of the existing methods are that the design of the structure of the laser itself will increase the complexity of the process and reduce the yield and reliability of the device.

In order to reduce the manufacturing cost and difficulty of the laser, the laser structure provided by the invention adopts a surface grating, which avoids the complicated steps required by the secondary epitaxy. In addition, because the size of the first-order Bragg grating is very small, generally hundreds of nanometers, the fabrication difficulty is relatively high. In order to reduce the difficulty and cost of fabrication, the laser of the present invention adopts a high-order grating, which further reduces the process complexity, and Improve the yield of laser fabrication.

The silicon-based surface high-order grating laser and its preparation method of the present invention will be described below with reference to FIGS. 1-7 .

FIG. 1 is a schematic structural diagram of a silicon-based surface high-order grating laser provided by an embodiment of the present invention. Please refer to FIG. 1. The silicon-based surface high-order grating laser includes:

substrate1;

an inverted ridge waveguide structure 2 disposed on the substrate 1;

an insulating layer 6 disposed on the upper layer of the waveguide structure 2;

A filling layer 5 is arranged between the waveguide structure 2 and the insulating layer 6; a grating layer jointly formed by the waveguide structure 2 and the filling layer 5;

Wherein, the upper surface of the waveguide structure 2 and the upper surface of the filling layer 5 are etched with Bragg gratings.

Optionally, the substrate 1 may be a general-purpose silicon substrate.

Optionally, the filling layer 5 may be made of polyimide or benzocyclobutene.

Optionally, the insulating layer 6 can be made of SiO ₂ .

According to the silicon-based surface high-order grating laser structure provided in this embodiment, the form of the surface grating is designed, so that the grating can be fabricated by ordinary photolithography technology, no secondary epitaxy is required, the manufacturing process is simple, easy to produce, and the Product yield.

It should be noted that the waveguide structure 2 in the middle in FIG. 1 is a structural schematic diagram of the waveguide structure 2 in this embodiment, and the waveguide structures 2 on both sides are modified to make the upper half of the waveguide structure 2 clearer. omitted.

In one or more embodiments, the silicon-based surface high-order grating laser structure may further include:

a patterned silicon dioxide layer 3 disposed between the substrate 1 and the waveguide structure;

a passivation layer 4 disposed between the buried oxide layer 3 and the filling layer 5;

a first electrode 7 disposed on the lower layer of the substrate 1;

The second electrode 8 is arranged on the upper layer of the insulating layer 6 .

Optionally, the buried oxide layer 3 may be silicon dioxide.

Optionally, the substrate 1 is an SOI substrate, and the structure of a general SOI substrate is a three-layer structure of "substrate silicon-buried oxide layer (silicon dioxide)-top layer silicon". The silicon oxide layer 3 refers to a layer of silicon dioxide etched with a groove shape on the bottom layer of substrate silicon. This layer of silicon dioxide is nucleated on the surface, so it grows preferentially in the etched trench. Second, the high aspect ratio silicon dioxide trench can limit the defect expansion of the material in the trench.

As an example, FIG. 2 is a schematic structural diagram of an inverted ridge waveguide structure provided by an embodiment of the present invention. Please refer to FIG. 2 . The waveguide structure 2 includes a buffer layer 21 and a lower cladding layer on top of the buffer layer 21 stacked in sequence. 22. The lower confinement layer 23, the quantum well active region 24, the upper confinement layer 25 and the upper cladding layer 26 respectively.

In other words, the inverted ridge waveguide structure 2 includes:

buffer layer 21;

The lower cladding layer 22 arranged on the upper layer of the buffer layer 21;

The lower respectively confinement layer 23 arranged on the upper layer of the lower cladding layer 22;

Quantum well active regions 24 arranged on the upper layer of the lower confinement layer 23 respectively;

An upper confinement layer 25 disposed on the upper layer of the quantum well active region 24;

The upper cladding layer 26 is provided on the upper layer of the upper confinement layer 25 respectively.

Specifically, the waveguide structure 2 of this embodiment may be a waveguide structure with an inverted ridge type III-V group submicron structure.

Exemplarily, the lower end of the lower confinement layer 23 is not higher than the upper end of the buried oxide layer 3 , which can reduce laser leakage.

For example, the material of the buffer layer 21 can be GaAs, and compared with the InP material, the lattice constant of GaAs and silicon is closer; the material of the lower cladding layer 22 can be N-InP, and the lower confinement layer 23 and the upper confinement layer 25 respectively The material of the quantum well can be 1.2QInGaAsP, the quantum well active region 24 can be a multilayer InGaAs/InGaAsP quantum well structure, the central wavelength can be adjusted to cover the 1.2-1.65 μm band by adjusting the composition and strain, and the material of the upper cladding layer 26 can be p -InP.

Exemplarily, the upper end of the upper cladding layer 26 and the upper end of the filling layer 5 are on the same plane, and then a Bragg grating is etched on the upper surface of the waveguide structure 2 and the upper surface of the filling layer 5 . FIG. 3 is one of the schematic diagrams of the Bragg grating structure provided by the embodiment of the present invention. Specifically, FIG. 3 is a schematic cross-sectional view of the grating layer in FIG. 1 along the planes where O, O1 and O2 are located. FIG. 4 is the second schematic diagram of the grating structure provided in the embodiment of the present invention. Specifically, FIG. 4 is a schematic cross-sectional diagram of the waveguide structure in FIG. 1 along the planes where O, O2 and O3 are located.

Please refer to FIG. 3 and FIG. 4, preferably, the groove width 52 of the Bragg grating in this embodiment and the width of the unetched region 51 between the grooves satisfy the following relationship:

Among them, d _s represents the width of the Bragg grating groove, n _s represents the effective refractive index of the Bragg grating groove, λ represents the Bragg wavelength corresponding to the Bragg grating, d _w represents the width of the unetched area between the grooves, and n _w represents the Bragg grating The effective refractive index of the unetched area;

Both p and q are positive integers, the period of the Bragg grating Λ=d _s +d _w , and the order of the Bragg grating m=p+q+1.

Wherein, the Bragg grating period of this embodiment satisfies the following formula (3):

mλ= _2neff Λ (3)

Among them, n _eff is the effective refractive index of the waveguide structure.

Preferably, for the Bragg grating of the laser in this embodiment, the groove width d _s is generally greater than 1 μm, which can be photolithographically performed by a contact photolithography machine, which is simple to manufacture and low in cost.

Preferably, for the Bragg grating of the laser in this embodiment, the length Λ of the entire period can be set to be greater than 5 μm to obtain higher reflection and transmission.

Preferably, the characteristic size of the Bragg grating in this embodiment is greater than 1 μm, and the order of the Bragg grating is greater than 9.

Preferably, the depth of the Bragg grating grooves in this embodiment is 0.5-0.7 microns, and the bottom of the Bragg grating grooves is higher than the lower surface of the filling layer. The distance from the top surface of the oxygen layer to the substrate.

In order to make Bragg grating lasers have higher reflectivity, more grating periods are required, which requires a relatively long cavity length, but because the growth of III-V materials on silicon is not yet mature, too long cavity The length of the cavity will also lead to a decrease in the yield, so the cavity length of the laser in this embodiment is selected as a length of 100 to 200 microns.

The reflectivity of the Bragg grating is also related to the etching depth of the grating. Generally speaking, the deeper the etching depth, the greater the impact on light propagation, the greater the change in the effective refractive index at the etching site, and the greater the grating coupling coefficient. A higher reflectivity can be obtained. However, if the reflectivity is too large, it will also increase the loss of light in the direction of propagation, which is not conducive to the formation of lasing and affects the stability of the laser. In this embodiment, after calculation by FDTD (Finite Difference Time Domain), the etching depth of the laser grating in this embodiment is 0.5 to 0.7 microns, that is, the etching depth of the laser grating is about 0.6 microns, and the Bragg grating groove The bottom is higher than the lower surface of the filling layer. The grating begins to affect the effective refractive index of the mode, and the reflectivity will not be too high, resulting in excessive loss.

In the preparation process of the grating, this embodiment uses a high-order grating to avoid complex and expensive manufacturing methods, so the feature size of the grating is required to be above 1 micron, and sufficient periods are required to obtain sufficient reflectivity, so the periods cannot Too long, considering comprehensively, the order of the Bragg grating in this embodiment is 20-30, that is, the value of the period is 5-8 microns.

Referring to FIGS. 1 and 4 , the silicon-based high-order surface grating laser of this embodiment is provided with an insulating layer 6 on the upper layer of the waveguide structure 2 . The insulating layer 6 can be a silicon dioxide isolation layer to play the role of insulation and isolation. On the upper layer of the inverted ridge waveguide structure 2 , the insulating layer 6 is opened out of a window to facilitate the injection of current into the inverted ridge waveguide structure 2 . As shown in Figure 4, because the grating etching groove is deeper than the unetched area, there is still a part of silicon dioxide filled in the groove, and in the area outside the groove, the second electrode 8 on the upper layer of the insulating layer 6 and the The inverted ridge waveguide structure 2 is in contact, which facilitates the injection of current.

When preparing the silicon-based surface high-order grating laser of this embodiment, first provide an SOI substrate, etch away the top layer silicon of the SOI substrate, SOI etches periodic rectangular silicon dioxide grooves along the crystal direction, A rectangular silicon dioxide trench is prepared on the BOX layer, the bottom of the trench leaks out from the upper surface of the silicon substrate 1 , and the aspect ratio of the trench is greater than or equal to 2. Then wet etching is used to prepare the V-shaped silicon trench on the silicon on SOI, and the etching solution can be KOH or other strong alkali. A high-quality inverted ridge III-V group waveguide structure 2 is grown on the silicon substrate by using ART technology. After the waveguide structure 2 micron line epitaxy is completed, the epitaxial trench part is on the same plane as the waveguide structure 2, and the end-face coupling is used. At the same time, it is beneficial to the effective coupling of light from the waveguide structure 2 to the silicon waveguide. Polyimide will be filled around the submicron ridge of the waveguide structure 2. After three-dimensional simulation by the finite difference time domain method (Finite Difference Time Domain, FDTD), the mode generated in the waveguide structure 2 (ie, the waveguide structure modes that allow photostable transport), can be well confined in submicron ridges with only a small fraction leaking into the underlying silicon substrate. The multiple quantum wells grown in submicron ridges are used for gain, the front and back cleave cavity surfaces are used for feedback, and the high-order surface grating obtained by photolithography is used for wavelength selection. Cleavage planes can be obtained by cleaving or etching using a focused ion beam (FIB) method. The second electrode 8 on the upper surface and the first electrode 7 on the back can realize current injection, and finally obtain a silicon-based high-order surface grating laser.

In this embodiment, the effect of single-mode lasing is realized by relying on the high-order surface grating, which is essentially a Bragg grating, and a suitable lasing wavelength can be obtained according to the Bragg equation. By changing the grating parameters according to the Bragg equation in the same laser array, gratings with different lasing wavelengths can be designed, and gratings with different lasing wavelengths can be made in the same laser array, and a high-order surface grating multi-wavelength laser can be obtained array.

In one or more embodiments, when preparing a silicon-based high-order surface grating laser, first prepare periodic grooves on a silicon substrate or an SOI substrate, the distance between the grooves is 3 μm, and the high-order surface grating has multiple wavelengths. Laser arrays require the etching of gratings with different lasing wavelengths. The high-order grating on the surface is partially etched in the part where the "inverted ridge" laser epitaxially extends the silicon dioxide groove, and the grating feature width is greater than 1 μm, which can be fabricated by standard photolithography technology. In the etched groove of the grating, It is filled with silicon dioxide to prevent the second electrode on the surface from entering the etched groove, causing metal to reflect light, thereby affecting the selection of the Bragg wavelength by the grating.

As shown in FIG. 3 , the horizontal black lines represent etched grooves. In this embodiment, four grating structures with different parameters are set, and the grating groove widths and groove pitches of the four different parameter grating structures are different. The surface grating prepared by a grating parameter will cover multiple "inverted ridge" submicron lines to reduce the complexity of preparation. The surface grating grooves of different parameters are all perpendicular to the "inverted ridge" submicron lines, and the surface gratings of different parameters will not cover each other. Each "inverted ridge" submicron line is covered by only one kind of grating. will not affect each other.

By changing the grating parameters according to the Bragg equation, different lasing wavelengths can be obtained, and finally a silicon-based high-order surface grating multi-wavelength laser is obtained. After parameter design and simulation, this embodiment provides the silicon-based high-order surface grating multi-wavelength laser array parameters of the four wavelengths in Table 1 below:

Table 1

Center wavelength (μm) Groove width (μm) Groove spacing (μm) grating1 1.54 1.11 5.54 grating2 1.55 1.12 5.59 grating3 1.56 1.13 5.63 grating4 1.57 1.14 5.67

FIG. 5 is a schematic diagram of the output spectrum simulation results of the four-wavelength silicon-based high-order surface grating laser provided by the embodiment of the present invention. Grating1, grating2, grating3 and grating4 respectively represent four grating parameters with different center wavelengths. The center wavelength difference between adjacent gratings is 10nm, the full width at half maximum (FWHM) is about 2.5nm, and the lasing peaks of adjacent gratings will not interfere with each other.

Fig. 6 is a flowchart of a method for preparing a silicon-based surface high-order grating laser provided by an embodiment of the present invention. As shown in Fig. 6, the method for preparing a silicon-based surface high-order grating laser includes:

S601. Provide a substrate;

S602, forming an inverted ridge waveguide structure on the upper surface of the substrate;

S603, filling the waveguide structure with a material that can be used for grating etching to form a filling layer; so that the waveguide structure and the filling layer together form a grating layer;

S604, forming an insulating layer on the upper surface of the waveguide structure and the upper surface of the filling layer; specifically, when making the insulating layer, it covers the waveguide structure and the filling layer, but the insulating material outside the groove on the waveguide structure will be engraved Only by etching and removing (that is, opening a window on the insulating layer on the waveguide structure and removing the insulating layer on the waveguide structure), can carriers flow into the waveguide structure to form a gain.

S605, forming a first electrode on the lower surface of the substrate;

S606, forming a second electrode on the upper surface of the insulating layer.

As an example, FIG. 7 is a schematic flowchart of a method for generating a waveguide structure provided by an embodiment of the present invention. Please refer to FIG. 7. The method includes:

S701. Etching a V-shaped groove on the upper surface of the substrate, and epitaxially forming a buffer layer in the V-shaped groove;

S702, forming a lower cladding layer on the buffer layer;

S703, forming a lower separate confinement layer on the upper layer of the lower cladding layer;

S704, forming quantum well active regions on the lower confinement layers respectively;

S705, forming an upper confinement layer on the quantum well active region;

S706, forming an upper cladding layer on the upper respective confinement layer.

It should be noted that some of the production details in the preparation method of this embodiment have been described in the above embodiments, and will not be repeated here.

According to the method provided by the invention to prepare the laser, the common photolithography technology can be used to make the grating, no secondary epitaxy is needed, the manufacturing process is simple, the production is easy, and the yield of the product is improved.

The device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network elements. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood and implemented by those skilled in the art without any creative effort.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A silicon-based surface high-order grating laser, characterized in that, comprising Substrate; an inverted ridge waveguide structure disposed over the substrate; an insulating layer disposed on the upper layer of the waveguide structure; providing a filling layer between the waveguide structure and the insulating layer; Wherein, the upper surface of the waveguide structure and the upper surface of the filling layer are provided with Bragg gratings. 2. The silicon-based surface high-order grating laser according to claim 1, further comprising: a patterned silicon dioxide layer disposed between the substrate and the waveguide structure; a passivation layer disposed between the buried oxide layer and the filling layer; a first electrode disposed on a lower layer of the substrate; The second electrode is arranged on the upper layer of the insulating layer. 3. The silicon-based surface high-order grating laser according to claim 2, wherein the waveguide structure comprises a buffer layer and a lower cladding layer, a lower confinement layer, Quantum well active region, upper confinement layer and upper cladding layer respectively. 4 . The silicon-based surface high-order grating laser according to claim 3 , wherein the distance from the lower surface of the lower confinement layer to the substrate is smaller than the distance from the upper surface of the buried oxide layer to the substrate. 5. The silicon-based surface high-order grating laser according to any one of claims 1-4, wherein the characteristic size of the Bragg grating is greater than 1 μm, the period of the grating is greater than 5 μm, and the order of the Bragg grating number greater than 9. 6. The silicon-based surface high-order grating laser according to any one of claims 1-4, wherein the groove width of the Bragg grating and the width of the unetched region between the grooves satisfy the following relationship: Among them, d _s represents the width of the Bragg grating groove, n _s represents the effective refractive index of the Bragg grating groove, λ represents the Bragg wavelength corresponding to the Bragg grating, d _w represents the width of the unetched area between the grooves, and n _w represents the Bragg grating The effective refractive index of the unetched area; Both p and q are positive integers, the period Λ=d _s +d _w of the Bragg grating, and the order m=p+q+1 of the Bragg grating. 7. The silicon-based surface high-order grating laser according to any one of claims 1-4, wherein the groove depth of the Bragg grating is 0.5-0.7 microns, and the bottom of the groove of the Bragg grating is as high as on the lower surface of the filling layer. 8. The silicon-based surface high-order grating laser according to any one of claims 1-4, wherein the cavity length of the waveguide structure is 100-200 microns. 9. A method for preparing a silicon-based surface high-order grating laser, characterized in that it comprises: providing a substrate; forming an inverted ridge waveguide structure on the upper surface of the substrate; Filling the waveguide structure with a material that can be used for grating etching to form a filling layer; so that the waveguide structure and the filling layer together form a grating layer; forming an insulating layer on the upper surface of the waveguide structure and the upper surface of the filling layer; forming a first electrode on the lower surface of the substrate; A second electrode is formed on the upper surface of the insulating layer. 10. The method for manufacturing a silicon-based surface high-order grating laser according to claim 9, wherein said forming an inverted ridge waveguide structure on the upper surface of the substrate comprises: Etching a V-shaped groove on the upper surface of the substrate, and epitaxially forming a buffer layer in the V-shaped groove; forming a lower cladding layer on the buffer layer; forming a lower respective confinement layer on the upper layer of the lower cladding layer; forming a quantum well active region on the lower confinement layer; forming an upper confinement layer on the active region of the quantum well; An upper cladding layer is formed on the upper respective confinement layer.