CN111916998A - Distributed feedback laser based on W3 photonic crystal defect waveguide and preparation method - Google Patents

Abstract

Embodiments of the present invention provide a distributed feedback laser based on a W3 photonic crystal defect waveguide and a preparation method. The distributed feedback laser includes a P electrode, a P doped layer, a quantum well active layer, an N doped layer and an N electrode; The source photonic crystal waveguide layer includes two microporous waveguide arrays, which are distributed on both sides of the P electrode. The microporous waveguide array is formed by arranging a plurality of microholes according to a preset array structure, and each microhole penetrates the P-doped layer. , quantum well active layer and N-doped layer, and cut off on the upper surface of the substrate; remove three columns of micro-holes in the two-dimensional pattern structure along the line defect photonic crystal waveguide direction to form a W3 photonic crystal defect waveguide. The embodiment of the present invention utilizes the slow light effect generated by the coupling of the forward wave and the reverse wave in the W3 photonic crystal defect waveguide to design an ultra-short laser resonator, thereby reducing the size of the chip, thereby reducing the cost of the device and improving the integratable performance of the chip.

Description

Distributed feedback laser based on W3 photonic crystal defect waveguide and preparation method

technical field

The invention relates to the field of integrated optoelectronic devices, in particular to a distributed feedback laser based on W3 photonic crystal defect waveguide and a preparation method.

Background technique

Distributed Feedback Laser (DFB-LD) is a laser that builds Bragg gratings in semiconductor lasers and relies on the mode selection principle of gratings to obtain specific lasing wavelengths. The grating of the DFB laser is distributed in the entire cavity of the laser, and the light wave can gain gain while being fed back. DFB-LD can be generally divided into two types: gain coupling and refractive index coupling. The former is to engrave the grating structure into the active region, so that the gain of the active region changes periodically, thereby producing a feedback effect on the optical guided mode in the laser cavity. . In the latter, the grating structure is engraved above the active area, and the optical guided mode of the laser cavity is fed back by acting on the evanescent field of the optical guided mode in the active area. However, the manufacturing process of the gain-coupled DFB-LD is complicated, the manufacturing cost is high, and the yield is low. Therefore, the refractive index coupling of the uniform grating is mainly used at present, and the III-V semiconductor material is generally used as the active layer of the multiple quantum well structure. The biggest feature of DFB laser is that it has very good monochromaticity (that is, spectral purity), its linewidth can generally be within 1MHz, and it has a very high side mode suppression ratio (SMSR), which can be as high as 40-50dB or more. DFB-LD chip is the core device of current 10G, 100G optical fiber communication network, enterprise Ethernet, cloud computing center and fifth-generation mobile communication network.

DFB-LD chips are widely used in optical fiber communication due to their good monochromaticity, tunable semiconductor laser absorption spectroscopy technology, including composition detection, medical treatment, atmospheric measurement, environmental measurement, atomic spectroscopy, including atomic clock, magnetometer, and precision measurement , night vision, isotope detection and other fields.

However, the current DFB-LD chip has a problem: the size is large, which is not conducive to chip integration, and the device cost is also high due to the large size.

SUMMARY OF THE INVENTION

In view of the problems in the prior art, the embodiments of the present invention provide a distributed feedback laser based on a W3 photonic crystal defect waveguide and a preparation method.

Specifically, the embodiments of the present invention provide the following technical solutions:

In a first aspect, an embodiment of the present invention provides a distributed feedback laser, including: a P electrode, a P-doped layer, a quantum well active layer, an N-doped layer, a substrate, and an N-electrode sequentially arranged from top to bottom ;

The P-doped layer, the quantum well active layer and the N-doped layer constitute an active photonic crystal waveguide layer;

The active photonic crystal waveguide layer includes two microporous waveguide arrays, the microporous waveguide array is formed by arranging a plurality of microholes according to a preset array structure, and each of the microholes penetrates the P-doped layer, the quantum well active layer and the N-doped layer, and the upper surface of the substrate is cut off;

The two micro-hole waveguide arrays are distributed on both sides of the P-electrode; wherein, the P-electrode is positioned above the photonic crystal waveguide layer without micro-holes;

The micro-holes in the two micro-hole waveguide arrays form a two-dimensional pattern structure, the two-dimensional pattern structure forms a two-dimensional plate photonic crystal, and the two-dimensional plate photonic crystal generates a photonic forbidden band, forming a line defect photonic crystal waveguide;

Wherein, three rows of micro-holes in the two-dimensional pattern structure are removed along the line defect photonic crystal waveguide direction to obtain a W3 photonic crystal defect waveguide.

Further, the preset array structure includes at least a triangular lattice structure or a tetragonal lattice structure.

Further, the cross-sectional shape of the micropores includes at least a circle, an ellipse, a regular polygon or a rectangle.

Further, in each micro-hole waveguide array, the shape and size of each micro-hole are the same, and the lattice period between the adjacent micro-holes around it is the same.

Further, the depth of the micropores exceeds 500 nm.

Further, the radius of the micropores is 80-180 nm.

Further, the microporous waveguide arrays on both sides of the P electrode form an ultrashort cavity of a photonic crystal slow optical waveguide structure, and the length of the ultrashort cavity of the photonic crystal slow optical waveguide structure is less than 100 μm.

In a second aspect, an embodiment of the present invention further provides a method for fabricating a distributed feedback laser as described in the first aspect, including:

Utilize vapor deposition method PECVD to grow _SiO2 layer on the substrate containing quantum wells or quantum dots;

Coating electron beam glue _on the surface of SiO layer;

Using the method of electron beam exposure to prepare the mask pattern of the microporous waveguide array on the electron beam glue;

Using ICP dry etching technology, the formed mask pattern is etched onto the _SiO2 layer;

Remove the electron beam glue left by the etching, complete the mask pattern transfer and the preparation of SiO ₂ hard mask;

One more ICP dry etching is performed to realize the etching of the P-doped layer, the N-doped layer, the quantum well active layer and the microporous waveguide array to obtain an active photonic crystal waveguide containing quantum wells or quantum dots. The micro-hole waveguide array in the photonic crystal waveguide is formed by arranging the micro-holes according to a preset array structure;

removing 3 rows of micro-holes in the two-dimensional pattern structure along the line defect photonic crystal waveguide direction to obtain a W3 photonic crystal defect waveguide;

The SiO ₂ layer is removed, and a P electrode is prepared on the side of the P-doped layer away from the quantum well active layer, and an N electrode is prepared at the side of the N-doped layer away from the quantum well active layer.

It can be seen from the above technical solutions that the distributed feedback laser based on the W3 photonic crystal defect waveguide and the preparation method provided by the embodiment of the present invention are provided with a micro-porous waveguide array on both sides of the P electrode, and the micro-porous waveguide array is formed according to No. A plurality of micro-holes arranged in a predetermined arrangement structure are formed, each micro-hole penetrates the P-doped layer, the quantum well active layer and the N-doped layer, and is on the substrate Surface cutoff. It can be seen that the embodiment of the present invention forms a two-dimensional flat photonic crystal by designing a deep etching air microporous structure, generating a photonic forbidden band, introducing defects into the complete photonic crystal, and using the photonic forbidden band to confine light to propagate in the defects , forming a line-defect photonic crystal waveguide. In the embodiment of the present invention, the abnormal dispersion in the defect waveguide of the W3 photonic crystal is used to make it have special optical gain characteristics. In the photonic band gap, the slow optical effect generated by the defect mode can increase the optical gain per unit transmission distance, and it is easy to realize that the gain exceeds the loss. The lasing conditions of the traditional DFB-LD laser can thus be shortened. In the W3 photonic crystal defect waveguide, due to the existence of multiple waveguide modes such as forward wave and backward wave in the wide W3 photonic crystal defect waveguide, the forward wave and backward wave with the same symmetry are at the frequency where the energy band crossing occurs. , the forward wave and the backward wave will generate strong coupling, splitting the dispersion curve at the original intersection and forming a flat area, which in turn produces the slow light effect, that is, the light oscillates back and forth repeatedly in the transmission direction. The advantage of this embodiment is that the width of the defect waveguide increases, the photonic crystal waveguide generates a micro-band gap effect due to the coupling of the fundamental mode and the higher-order mode, and there is a slow light region of the fundamental mode. The filter characteristic of the micro-band gap is generated on the transmission spectrum of the waveguide of this embodiment. Compared with other frequency bands, the slow light significantly enhances the optical gain, and the gain spectrum of the waveguide produces a gain double peak. In addition, the gain spectrum can be controlled by designing the dispersion relationship of the photonic crystal waveguide. The embodiment of the present invention utilizes the photonic crystal slow light effect to design and shorten the resonant cavity structure of the traditional DFB-LD laser chip, which can reduce the volume of the DFB-LD laser chip by more than one time. Therefore, the same size wafer can produce more than double the number of DFB-LD laser chips LD laser chip, which can reduce device cost. In addition, the embodiments of the present invention make the DFB-LD laser chip easier to integrate later, thereby realizing the design and manufacture of active optoelectronic devices with more complex processes and more functions. It can be seen that the embodiment of the present invention utilizes the photonic crystal slow light effect to design an ultra-short laser resonator cavity, thereby reducing the size of the chip, thereby reducing the cost of the device and improving the integratable performance of the chip.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a top view of a distributed feedback laser based on a W3 photonic crystal defect waveguide provided by an embodiment of the present invention;

2 is a cross-sectional view of a distributed feedback laser based on a W3 photonic crystal defect waveguide provided by an embodiment of the present invention;

3 is a three-dimensional schematic diagram of a distributed feedback laser based on a W3 photonic crystal defect waveguide provided by an embodiment of the present invention;

4 is a schematic structural diagram of an active photonic crystal waveguide prepared according to an embodiment of the present invention;

5 is a top view of a distributed feedback laser without removing three rows of micro-holes according to an embodiment of the present invention;

6 is a cross-sectional view of a distributed feedback laser without removing three rows of micro-holes according to an embodiment of the present invention.

Detailed ways

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

1 shows a top view of a distributed feedback laser based on a W3 photonic crystal defect waveguide provided by an embodiment of the present invention; FIG. 2 shows a cross-sectional view of the distributed feedback laser based on a W3 photonic crystal defect waveguide provided by an embodiment of the present invention. FIG. 3 shows a three-dimensional schematic diagram of a distributed feedback laser based on a W3 photonic crystal defect waveguide provided by an embodiment of the present invention. As shown in FIG. 1 , FIG. 2 and FIG. 3 , the distributed feedback laser provided in this embodiment includes: a P electrode 9 , a P-doped layer 8 , a quantum well active layer 3 , and an N-doped layer arranged in sequence from top to bottom Impurity layer 5, substrate 6 and N electrode 7;

The P-doped layer 8, the quantum well active layer 3 and the N-doped layer 5 constitute an active photonic crystal waveguide layer 1; the active photonic crystal waveguide layer 1 includes two microporous waveguides Array 4, the micro-hole waveguide array 4 is formed by arranging a plurality of micro-holes 2 according to a preset array structure, and each of the micro-holes 2 penetrates the P-doped layer 8, the quantum well active layer 3 and the The N-doped layer 5 is cut off on the upper surface of the substrate 6;

The two micro-hole waveguide arrays 4 are distributed on both sides of the P-electrode 9; wherein, the position of the P-electrode is set above the photonic crystal waveguide layer without micro-holes, and the P-electrode cannot be deposited on both sides in the micropores;

Wherein, the microholes 2 in the two microhole waveguide arrays 4 form a two-dimensional pattern structure, the two-dimensional pattern structure forms a two-dimensional plate photonic crystal, and the two-dimensional plate photonic crystal generates a photonic forbidden band and forms a line defect Photonic crystal waveguide;

Wherein, three rows of micro-holes in the two-dimensional pattern structure are removed along the line defect photonic crystal waveguide direction to obtain a W3 photonic crystal defect waveguide.

As shown in FIG. 5 and FIG. 6 , the distributed feedback laser provided in this embodiment includes an active photonic crystal waveguide layer 1 , and the active photonic crystal waveguide layer 1 includes two microporous waveguide arrays 4 . The microporous waveguide arrays All the microholes 2 in 4 penetrate through the P-doped layer 8 , the quantum well active layer 3 and the N-doped layer 5 . All the microholes 2 in the microhole waveguide array 4 have the same specific cross-sectional shape, and the circle shown in FIG. 1 is taken as an example in this embodiment. All the microholes 2 are arranged in a two-dimensional pattern structure according to the designed structural parameters corresponding to the output wavelength of the laser. In this embodiment, the triangular lattice shown in FIG. 1 is taken as an example, that is, in the two-dimensional pattern structure, all the microholes 2 are The array is arranged, and all the microholes 2 have the same radius and the same lattice period between the adjacent microholes 2 around them, so that all the microholes 2 form a rectangular microhole waveguide array 4 on the active photonic crystal waveguide layer 1 as a whole, The length of the long side is in the range of 5-100 μm, the length of the short side is in the range of 2-50 μm, and the area where the P electrode 9 is located is not provided with a photonic crystal hole.

In this embodiment, the micro-holes are combined and arranged into a special two-dimensional pattern structure, and the size and arrangement of the micro-holes are designed with different structures, lengths, periods, and structural parameters according to the working wavelength of the DFB-LD chip. The arrangement structure includes: But not limited to triangular lattice or tetragonal lattice structure.

In this embodiment, it should be noted that the number of columns of microholes arranged on both sides of the P electrode 9 is generally more than 4 columns, so as to ensure sufficient periodic structure to form a photonic band gap.

It is understandable that the specific cross-sectional shape of the above-mentioned micropores 2 may include a circle, an ellipse, a regular polygon, a rectangle, and the like. Correspondingly, the above-mentioned structural parameters of the micropore 2 include inner diameter, long axis length, short axis length, rotation angle or side length, and the like. The specific two-dimensional shape of the corresponding micro-hole waveguide array 4 is a rectangle, including different long and short side lengths, inner photonic crystal hole radii, and lattice periods.

The total thickness of the P-doped layer 8 described in this embodiment, the quantum well active layer 3, the N-doped layer 5, and the substrate 6 exceeds 1 μm. A metal P-electrode 9 is deposited on the P-doped layer 8, and P The position of the electrode 9 is above the photonic crystal waveguide area without the etching of the microhole 2, that is, the area on the plane of the active photonic crystal waveguide layer 1 except for the two microhole waveguide arrays 4, the P electrode 9 cannot be deposited on the microholes on both sides. 2, the length of the P electrode 9 is less than 100 microns, and the width is related to the radius and lattice period of the microholes 2 in the microhole waveguide array 4.

On the basis of FIG. 5 and FIG. 6 , in this embodiment, three rows of micro-hole removal operations are required. As shown in FIG. 1 , FIG. 2 and FIG. 3 , in this embodiment, in addition to disposing two In addition to the micro-hole waveguide array 4, three rows of micro-holes in the two-dimensional pattern structure are further removed along the line defect photonic crystal waveguide direction to obtain a W3 photonic crystal defect waveguide.

It should be noted that, in this embodiment, some rows of micro-holes are removed on the basis of the original micro-hole waveguide array 4, that is, the number of columns is reduced by 3 rows compared with the original, and the corresponding electrode width can be increased at the same time, thereby obtaining the present invention. In the defective waveguide of the embodiment, due to the relatively large width of the defective waveguide in this embodiment, there are multiple waveguide modes, in which the waveguide modes of the forward wave and the backward wave are strongly coupled, so that the dispersion curve at the original intersection point is split and formed. The flat area in turn produces the slow light effect, that is, the light oscillates back and forth repeatedly in the transmission direction. The advantage of this embodiment is that the photonic crystal waveguide generates a micro-band gap effect due to the coupling of the fundamental mode and the higher-order mode, and there is a slow light region of the fundamental mode. The filter characteristic of the micro-band gap is generated on the transmission spectrum of the waveguide of this embodiment. Compared with other frequency bands, the slow light significantly enhances the optical gain, and the gain spectrum of the waveguide produces a gain double peak. The gain spectrum can be controlled by designing the dispersion relationship of the photonic crystal waveguide.

It can be seen from the above technical solutions that the distributed feedback laser provided by the embodiment of the present invention is provided with a microporous waveguide array on both sides of the P electrode, and the microporous waveguide array is composed of multiple arrays arranged according to the first preset arrangement structure. A plurality of micro-holes are formed, and each micro-hole penetrates the P-doped layer, the quantum well active layer and the N-doped layer, and is cut off on the upper surface of the substrate. It can be seen that the embodiment of the present invention forms a two-dimensional flat photonic crystal by designing a deep etching air microporous structure, generating a photonic forbidden band, introducing defects into the complete photonic crystal, and using the photonic forbidden band to confine light to propagate in the defects , forming a line-defect photonic crystal waveguide. It can be seen that, in this embodiment, defects are introduced into the complete photonic crystal, and the photonic forbidden band is used to confine light to propagate in the defects, so as to form a line defect photonic crystal waveguide. In the embodiment of the present invention, the abnormal dispersion in the photonic crystal waveguide is used to make it have special optical gain characteristics. In the photonic band gap, the slow light effect generated by the defect mode can increase the optical gain per unit transmission distance, and it is easy to realize the laser with the gain exceeding the loss. lasing conditions, so the cavity structure of conventional DFB-LD lasers can be shortened. In addition, the embodiment of the present invention makes use of the abnormal dispersion in the photonic crystal waveguide to make it have special optical gain characteristics. In the photonic band gap, the slow optical effect generated by the defect mode can increase the optical gain per unit transmission distance, and it is easy to realize that the gain exceeds the loss. The lasing conditions of the traditional DFB-LD laser can thus be shortened. In addition, on this basis, the embodiment of the present invention further reduces 3 rows of micro-holes to form a W3 photonic crystal defect waveguide based on the original micro-hole waveguide array. The waveguide mode causes strong coupling between the forward wave and the backward wave, splitting the dispersion curve at the original intersection and forming a flat area, which in turn produces the slow light effect, that is, the light oscillates back and forth repeatedly in the transmission direction. The advantage of this embodiment is that the photonic crystal waveguide generates a micro-band gap effect due to the coupling of the fundamental mode and the higher-order mode, and there is a slow light region of the fundamental mode. The filter characteristic of the micro-band gap is generated on the transmission spectrum of the waveguide of this embodiment. Compared with other frequency bands, the slow light significantly enhances the optical gain, and the gain spectrum of the waveguide produces a gain double peak. In addition, the gain spectrum can be controlled by designing the dispersion relationship of the photonic crystal waveguide. In this embodiment, the photonic crystal slow light effect is used to design and shorten the resonant cavity structure of the traditional DFB-LD laser chip, which can reduce the volume of the DFB-LD laser chip by more than one time. Therefore, the same size wafer can produce more than double the number of DFB-LD laser chips. The laser chip can reduce the cost of the device. In addition, this embodiment makes the DFB-LD laser chip easier to integrate later, thereby realizing the design and manufacture of active optoelectronic devices with more complex processes and more functions. It can be seen that the present embodiment utilizes the photonic crystal slow light effect to design an ultra-short laser resonator cavity, so that the chip volume can be reduced, the device cost can be reduced, and the chip integration performance can be improved.

Based on the content of the above embodiment, in this embodiment, the depth of the micropores exceeds 500 nm.

In this embodiment, it should be noted that the longitudinal confinement of the optical field depends on the refractive index difference between the P-doped layer, the quantum well active layer, and the N-doped layer. Therefore, the longitudinal distribution of the optical field exceeds 500 nm, and exceeds Only 500nm can achieve effective localization and regulation of the light field.

Based on the content of the foregoing embodiment, in this embodiment, the radius of the micropore is 80-180 nm.

In this embodiment, it should be noted that for a laser with a communication band of 1550 nm, only when the radius is 80-180 nm can the effective band gap confinement and slow light enhancement effect be achieved.

Based on the content of the above embodiment, in this embodiment, the microporous waveguide arrays on both sides of the P electrode form an ultra-short cavity of a photonic crystal slow optical waveguide structure, and the length of the ultrashort cavity of the photonic crystal slow optical waveguide structure is less than 100 μm.

In this embodiment, it should be noted that the cavity length of a traditional DFB laser is more than 200 μm, and the cavity length of this embodiment can be controlled to be less than 100 μm, so the cavity length can be shortened by at least half, and the yield can be at least doubled.

The ultra-short cavity photonic crystal DFB-LD provided in this embodiment forms a two-dimensional flat photonic crystal through a specially designed deep etching of the air hole structure, generates a photonic band gap, introduces defects in the complete photonic crystal, and utilizes the photonic band gap. Confining light to propagate in the defects, forming line defect photonic crystal waveguides. Using the abnormal dispersion in the photonic crystal waveguide makes it have special optical gain characteristics. In the photonic band gap, the slow light effect generated by the defect mode can increase the optical gain per unit transmission distance, and it is easy to realize the laser lasing condition where the gain exceeds the loss. Therefore, the cavity structure of the conventional DFB-LD laser can be shortened.

FIG. 4 shows the active photonic crystal waveguide structure actually prepared according to the above embodiment. According to the above preparation process, the deep etching of the InP-based photonic crystal air holes 2 with a depth of more than 1 micron (the radius of the air holes 2 is about 100 nm) is successfully achieved, and an InP-based active photonic crystal waveguide with an aspect ratio greater than 14 is obtained.

Another embodiment of the present invention provides a method for fabricating a distributed feedback laser as provided in the foregoing embodiment, the method includes the following processing steps:

Step 101 : growing a SiO ₂ layer on a substrate containing quantum wells or quantum dots by means of vapor deposition method PECVD;

Step 102: coating the surface of the SiO ₂ layer with electron beam glue;

Step 103 : preparing a mask pattern of the microporous waveguide array on the electron beam glue by using an electron beam exposure method;

Step 104: using the ICP dry etching technology to etch the formed mask pattern onto the _SiO2 layer;

Step 105: remove the electron beam glue remaining in the etching, and complete the transfer of the mask pattern and the preparation of the SiO ₂ hard mask;

Step 106 : perform another ICP dry etching to realize the etching of the P-doped layer, the N-doped layer, the quantum well active layer and the microporous waveguide array to obtain an active photonic crystal waveguide containing quantum wells or quantum dots , the micro-hole waveguide array in the photonic crystal waveguide is formed by arranging micro-holes according to a preset array structure, as shown in FIG. 5 and FIG. 6 , remove 3 columns in the two-dimensional pattern structure along the line defect photonic crystal waveguide direction Micro-holes were obtained to obtain W3 photonic crystal defect waveguides, as shown in Figure 1 and Figure 2.

Step 107 : remove the SiO ₂ layer, and prepare a P electrode on the side of the P-doped layer away from the quantum well active layer, and prepare a side of the N-doped layer away from the quantum well active layer N electrode.

In this embodiment, the quantum well active layer may be a quantum well active layer of InGaAsP material.

In the distributed feedback laser provided in this embodiment, the entire fabrication process of the photonic crystal active waveguide structure is performed on a III-V semiconductor epitaxial wafer containing a quantum well active region.

Specifically, the growth method includes: using PECVD technology to grow a SiO ₂ layer with a thickness of 200-300 nm on the InP substrate sheet; throwing on the surface of SiO ₂ electron beam glue Zep520A with a thickness of about 200 nm; Make a mask pattern on the electron beam glue; use the ICP dry etching technology to etch the formed electron beam glue mask pattern on the SiO ₂ layer; remove the electron beam glue remaining in the previous step of etching to complete the pattern transfer and SiO _2. Preparation of hard mask; ICP dry etching is performed again to realize the etching of the P-doped layer 8 and N-doped layer 5 of InP material and the quantum well active layer 3 of InGaAsP material, so far to prepare a quantum well active layer containing quantum The InP photonic crystal waveguide in the active region of the trap, the (photonic crystal) microhole waveguide array 4 in the waveguide is regularly arranged by the microholes 2; the _SiO2 layer is removed; finally, the N electrodes 7 and 7 are prepared by processes such as thinning and sputtering. P electrode 9. In this embodiment, it should be noted that when it is necessary to remove three rows of micro-holes in the two-dimensional pattern structure along the waveguide direction of the line defect photonic crystal, the defect waveguide of the W3 photonic crystal is obtained.

The device embodiments described above are only illustrative, wherein 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 over multiple network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solutions of the embodiments of the present invention. Those of ordinary skill in the art can understand and implement it without creative effort.

From the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and certainly can also be implemented by hardware. Based on this understanding, the above-mentioned technical solutions can be embodied in the form of software products in essence or the parts that make contributions to the prior art, and the computer software products can be stored in computer-readable storage media, such as ROM/RAM, magnetic A disc, an optical disc, etc., includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform the methods described in various embodiments or some parts of the embodiments.

Furthermore, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply existence between these entities or operations any such actual relationship or sequence. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

Furthermore, in the present invention, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not 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 The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; 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 embodiments of the present invention.

Claims (8)

1. a distributed feedback laser based on W3 photonic crystal defect waveguide, is characterized in that, comprises: P electrode, P doped layer, quantum well active layer, N doped layer, substrate set successively from top to bottom and N electrode; The P-doped layer, the quantum well active layer and the N-doped layer constitute an active photonic crystal waveguide layer; The active photonic crystal waveguide layer includes two microporous waveguide arrays, the microporous waveguide array is formed by arranging a plurality of microholes according to a preset array structure, and each of the microholes penetrates the P-doped layer, the quantum well active layer and the N-doped layer, and the upper surface of the substrate is cut off; The two micro-hole waveguide arrays are distributed on both sides of the P-electrode; wherein, the P-electrode is positioned above the photonic crystal waveguide layer without micro-holes; The micro-holes in the two micro-hole waveguide arrays form a two-dimensional pattern structure, the two-dimensional pattern structure forms a two-dimensional plate photonic crystal, the two-dimensional plate photonic crystal generates a photonic forbidden band, and a photon is formed through a line defect crystal waveguide; Wherein, three rows of micro-holes in the two-dimensional pattern structure are removed along the line defect photonic crystal waveguide direction to obtain a W3 photonic crystal defect waveguide. 2 . The distributed feedback laser according to claim 1 , wherein the preset array structure at least comprises a triangular lattice structure or a tetragonal lattice structure. 3 . 3 . The distributed feedback laser according to claim 1 , wherein the cross-sectional shape of the micro-hole at least includes a circle, an ellipse, a regular polygon or a rectangle. 4 . 4 . The distributed feedback laser according to claim 1 , wherein in each micro-hole waveguide array, the shape and size of each micro-hole are the same, and the lattice period between adjacent micro-holes around it is the same. 5 . 5 . The distributed feedback laser of claim 1 , wherein the depth of the micro-holes exceeds 500 nm. 6 . 6 . The distributed feedback laser according to claim 1 , wherein the radius of the micro-hole is 80-180 nm. 7 . 7 . The distributed feedback laser according to claim 1 , wherein the microporous waveguide arrays on both sides of the P electrode form an ultrashort cavity with a photonic crystal slow optical waveguide structure, and the ultrashort cavity of the photonic crystal slow optical waveguide structure is formed. The length is less than 100μm. 8. A method for preparing a distributed feedback laser according to any one of claims 1 to 7, characterized in that, comprising: Utilize vapor deposition method PECVD to grow _SiO2 layer on the substrate containing quantum wells or quantum dots; Coating electron beam glue _on the surface of SiO layer; Using the method of electron beam exposure to prepare the mask pattern of the microporous waveguide array on the electron beam glue; Using ICP dry etching technology, the formed mask pattern is etched onto the _SiO2 layer; Remove the electron beam glue left by the etching, complete the mask pattern transfer and the preparation of SiO ₂ hard mask; One more ICP dry etching is performed to realize the etching of the P-doped layer, the N-doped layer, the quantum well active layer and the microporous waveguide array to obtain an active photonic crystal waveguide containing quantum wells or quantum dots. The micro-hole waveguide array in the photonic crystal waveguide is formed by arranging the micro-holes according to a preset array structure; removing 3 rows of micro-holes in the two-dimensional pattern structure along the line defect photonic crystal waveguide direction to obtain a W3 photonic crystal defect waveguide; The SiO ₂ layer is removed, and a P electrode is prepared on the side of the P-doped layer away from the quantum well active layer, and an N electrode is prepared at the side of the N-doped layer away from the quantum well active layer.

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