Silicon nitride waveguide and gallium nitride visible light source coupling structure based on metasurface

Abstract

The invention relates to a silicon nitride waveguide and gallium nitride visible light source coupling structure based on a metasurface, and belongs to the technical field of optoelectronic integration. The structure comprises a silicon substrate, a silicon dioxide cladding, a silicon nitride waveguide layer / metasurface structure, a BCB bonding layer, a P-type gallium nitride layer, a gallium nitride multi-quantum well layer, an N-type gallium nitride layer and a P / N-type electrode from bottom to top. The size of the silicon nitride waveguide is designed to be matched with the visible light single-mode transmission condition and the gallium nitride light-emitting wavelength range, the periodic metasurface structure is etched and prepared on the silicon nitride waveguide layer to regulate and control the amplitude, phase and polarization of the gallium nitride visible light, and high-efficiency coupling of the visible light and the silicon nitride waveguide is achieved. And meanwhile, integration of two different material systems is realized through the BCB bonding layer. The design can effectively realize the integration of the visible light source of the silicon nitride photonic integrated chip, solves the problems that the coupling loss of the silicon nitride waveguide and the visible light laser is large, the alignment precision requirement is high and the like, and provides a light source implementation scheme for chip-level biomedical detection and spectral analysis.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic integration, and relates to a supersurface-based silicon nitride waveguide and gallium nitride visible light source coupling structure. Background Art

[0002] Optoelectronic integration technology integrates optoelectronic materials and functional microstructures on a single chip to realize system functions, and has outstanding advantages such as low power consumption, high speed, high reliability, and small size. Silicon nitride is compatible with CMOS technology, has low waveguide transmission loss, high nonlinear coefficient, and can support a wide range of optical wavelengths. It has important applications in optical communications, medical sensing and other fields. However, it is an indirect bandgap material and cannot emit light directly. It needs to be coupled with an external light source to realize complete system functions. Gallium nitride is a direct bandgap semiconductor material. Through the adjustment of quantum well components, it can realize an efficient, wide-wavelength range visible light source. At present, the coupling of silicon nitride photonic chips and gallium nitride visible light sources faces difficulties such as large coupling loss and high alignment accuracy requirements.

[0003] Therefore, the present invention combines silicon nitride waveguides with metasurface structures, and utilizes the two-dimensional interface of the subwavelength scale structure to precisely control the amplitude, phase, and polarization of light in the visible light wavelength range, thereby achieving efficient control and coupling of the light field between the gallium nitride light source and the silicon nitride waveguide, thereby being applied in the fields of visible light communication, biomedicine, intelligent sensing, etc. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a coupling structure of silicon nitride waveguide and gallium nitride visible light source based on metasurface. To solve the problems of large size, low speed and instability of existing similar systems, the optical clock generation part in the photon front end adopts DFB and high quality factor micro-ring feedback injection locking to realize high-quality optical frequency comb, and is hybrid integrated with the electro-optical sampling part, electrical ADC and DSP part. This design can significantly improve the sampling rate of the photonic analog-to-digital conversion chip and reduce the time jitter. Through the hybrid integration of photonic devices and electronic devices, and making full use of the advantages of the large bandwidth of photonic devices, the present invention effectively improves the analog-to-digital conversion sampling rate, significantly reduces the system size and power consumption compared with traditional solutions, shortens the signal interconnection distance, enhances chip synchronization, and greatly reduces time jitter.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The coupling structure of silicon nitride waveguide and gallium nitride visible light source based on metasurface includes:

[0007] Silicon substrate;

[0008] a silicon dioxide cladding layer on the silicon substrate;

[0009] a silicon nitride waveguide layer on the silicon dioxide cladding layer, the cross-sectional dimensions of which support single-mode transmission in the visible light wavelength range;

[0010] A metasurface structure located on the silicon nitride waveguide layer, wherein the metasurface structure has periodic sub-wavelength-level holes for precisely controlling the amplitude, phase and polarization of light in the visible light wavelength range;

[0011] A BCB bonding layer located on the metasurface structure, used for bonding the silicon nitride waveguide layer to the gallium nitride device;

[0012] GaN devices, including:

[0013] P-type gallium nitride layer;

[0014] A gallium nitride multi-quantum well layer located on the P-type gallium nitride layer;

[0015] An N-type gallium nitride layer located on the gallium nitride multi-quantum well layer;

[0016] A P-type electrode located on the P-type gallium nitride layer;

[0017] An N-type electrode is located on the N-type gallium nitride layer.

[0018] Furthermore, the characteristic size of the metasurface structure is smaller than the shortest wavelength to be controlled, 380 nanometers.

[0019] Furthermore, the BCB bonding layer is used to achieve bonding and fixing of silicon nitride devices and gallium nitride devices, has a thickness of 150 nanometers, and is transparent to wavelengths in the visible light range.

[0020] Furthermore, the hole shape of the super surface structure is circular, square or triangular.

[0021] Furthermore, the gallium nitride device has a same-plane electrode structure and realizes light emission through electric pumping.

[0022] The beneficial effect of the present invention is that the present invention combines silicon nitride waveguides with metasurface structures, uses the two-dimensional interface of subwavelength scale structures to precisely control the amplitude, phase and polarization of light in the visible light wavelength range, and realizes efficient control and coupling of the light field of gallium nitride light source and silicon nitride waveguide. This design can reduce the difficulty of integrating visible light sources on silicon nitride photonic chips, reduce coupling losses, and improve process tolerance and chip reliability.

[0023] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 Schematic diagram of the coupling structure of silicon nitride waveguide and gallium nitride visible light source based on metasurface;

[0026] Figure 2 It is a cross-sectional layered schematic diagram of the present invention.

[0027] Figure numerals: 101 - silicon substrate, 102 - silicon dioxide cladding, 103 - silicon nitride waveguide layer, 104 - supersurface structure, 105 - BCB bonding layer, 106 - P-type gallium nitride layer, 107 - gallium nitride multi-quantum well layer, 108 - N-type gallium nitride layer, 109 - P-type electrode, 110 - N-type electrode. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0029] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0030] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0031] Example 1

[0032] See also Figure 1 , which is a supersurface-based silicon nitride waveguide and gallium nitride visible light source coupling structure, including, from bottom to top, a silicon substrate 101, a silicon dioxide cladding 102, a silicon nitride waveguide layer 103, a supersurface structure 104, a BCB bonding layer 105, a P-type gallium nitride layer 106, a gallium nitride multi-quantum well layer 107, an N-type gallium nitride layer 108, a P-type electrode 109 and an N-type electrode 110.

[0033] Among them, the silicon substrate 101 is a substrate layer of silicon nitride on an insulator, with a thickness of about 725 microns; the silicon dioxide cladding 102 has a refractive index of about 1.44, and as a low-refractive-index material, it limits the light field in the silicon nitride waveguide layer 103, and the overall thickness is about 5 microns; the cross-sectional size of the silicon nitride waveguide layer 103 is 150 nanometers × 800 nanometers, which can support single-mode transmission of visible light wavelengths from 380 nanometers to 740 nanometers; the metasurface structure 104 is a periodic subwavelength-level hole etched on the silicon nitride waveguide layer 103 to achieve the regulation of the intensity, phase and polarization characteristics of the visible light wavelength range, and its characteristic size is 100 nanometers, which is smaller than the shortest wavelength of 380 nanometers to be regulated; the BCB bonding layer 105 is used to achieve the bonding and fixation of silicon nitride devices and gallium nitride devices, and its thickness is about 150 nanometers, and it is transparent to wavelengths in the visible light range.

[0034] Layered cross-section diagram Figure 2 ,like Figure 2 As shown in the figure, the metasurface periodic structure is a sub-wavelength periodic porous structure prepared by the silicon nitride waveguide layer. The shape of the holes can be circular, square, triangular and other shapes. The scale, period and arrangement of the porous array can be varied as long as the fine control of the visible light wavelength range of gallium nitride is met. The BCB layer is used to complete the bonding and connection of two devices or chips. It is transparent to the visible light wavelength.

[0035] In this embodiment, the silicon nitride waveguide and gallium nitride visible light source coupling structure is based on the metasurface. The size of the silicon nitride waveguide can support single-mode transmission in the wavelength range of the gallium nitride visible light source. The periodic metasurface structure realizes the high-efficiency coupling of gallium nitride visible light into the silicon nitride waveguide. The gallium nitride visible light source is a coplanar electrode structure, and light is emitted through electric pumping. The BCB material and the silicon dioxide cladding that are transparent to the wavelength interact with the metasurface structure through the surface incidence to achieve low-loss coupling.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A silicon nitride waveguide and gallium nitride visible light source coupling structure based on a metasurface, characterized by: include: Silicon substrate; a silicon dioxide cladding layer on the silicon substrate; a silicon nitride waveguide layer on the silicon dioxide cladding layer, the cross-sectional dimensions of which support single-mode transmission in the visible light wavelength range; A metasurface structure located on the silicon nitride waveguide layer, wherein the metasurface structure has periodic sub-wavelength-level holes for precisely controlling the amplitude, phase and polarization of light in the visible light wavelength range; A BCB bonding layer located on the metasurface structure, used for bonding the silicon nitride waveguide layer to the gallium nitride device; GaN devices, including: P-type gallium nitride layer; A gallium nitride multi-quantum well layer located on the P-type gallium nitride layer; An N-type gallium nitride layer located on the gallium nitride multi-quantum well layer; A P-type electrode located on the P-type gallium nitride layer; An N-type electrode is located on the N-type gallium nitride layer.

2. The silicon nitride waveguide and gallium nitride visible light source coupling structure based on a metasurface according to claim 1, characterized in that: The characteristic size of the metasurface structure is smaller than the shortest wavelength to be controlled, 380 nanometers.

3. The silicon nitride waveguide and gallium nitride visible light source coupling structure based on a metasurface according to claim 1, characterized in that: The BCB bonding layer is used to achieve bonding and fixing of silicon nitride devices and gallium nitride devices, has a thickness of 150 nanometers, and is transparent to wavelengths in the visible light range.

4. The silicon nitride waveguide and gallium nitride visible light source coupling structure based on a metasurface according to claim 1, characterized in that: The hole shape of the super surface structure is circular, square or triangular.

5. The silicon nitride waveguide and gallium nitride visible light source coupling structure based on a metasurface according to claim 1, characterized in that: The gallium nitride device has a same-plane electrode structure and realizes light emission through electric pumping.

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