Metasurface-based coupling structure of silicon nitride waveguide and gallium nitride visible light source

Abstract

The application relates to a gallium nitride visible light source coupling structure based on a silicon nitride super-surface waveguide, and belongs to the technical field of optoelectronic integration. The structure comprises, from bottom to top, a silicon substrate, a silicon dioxide cladding layer, a silicon nitride waveguide layer / super-surface 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 P / N electrodes. The application matches the visible light single-mode transmission condition with the gallium nitride light-emitting wavelength range by designing the size of the silicon nitride waveguide, etches a periodic super-surface structure on the silicon nitride waveguide layer to control the amplitude, phase and polarization of the visible light of the gallium nitride, realizes high-efficiency coupling of the visible light and the silicon nitride waveguide, and realizes integration of two different material systems through the BCB bonding layer. The design can effectively realize visible light source integration of a silicon nitride photonic integrated chip, solve the problems of large coupling loss of the silicon nitride waveguide and the visible light laser and high alignment precision requirement, and provide an optical source implementation scheme for chip-level biological medical detection and spectrum 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, with outstanding advantages such as low power consumption, high speed, high reliability, and small size. Silicon nitride is compatible with CMOS processes, 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. By adjusting the quantum well components, it can realize an efficient, wide-wavelength visible light source. Currently, 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 uses 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 visible light communication, biomedicine, intelligent sensing and other fields. 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 photonic 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 located on the silicon dioxide cladding layer, having a cross-sectional dimension supporting 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 subwavelength-level holes for precisely controlling the amplitude, phase, and polarization of light in the visible 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 fixation of the silicon nitride device and the gallium nitride device, has a thickness of 150 nanometers, and is transparent to wavelengths in the visible light range.

[0020] Furthermore, the hole shape of the metasurface 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 effects of this invention lie in its ability to combine silicon nitride waveguides with metasurface structures, utilizing a subwavelength-scale two-dimensional interface to precisely control the amplitude, phase, and polarization of light in the visible wavelength range. This allows for efficient control and coupling of the light field between the gallium nitride light source and the silicon nitride waveguide. This design can simplify the integration of visible light sources on silicon nitride photonic chips, reduce coupling losses, and improve process tolerances and chip reliability.

[0023] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may 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 with reference to the accompanying drawings, in which:

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

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

[0027] Reference numerals: 101 - silicon substrate, 102 - silicon dioxide cladding, 103 - silicon nitride waveguide layer, 104 - metasurface 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 means of 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 are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

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

[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 there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional 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] Embodiment 1

[0032] See Figure 1 A kind of based on super surface silicon nitride waveguide and gallium nitride visible light source coupling structure, from bottom to top includes silicon substrate 101, silicon dioxide cladding 102, silicon nitride waveguide layer 103, super surface structure 104, BCB bonding layer 105, P type gallium nitride layer 106, gallium nitride multi quantum well layer 107, N type gallium nitride layer 108, P type electrode 109 and N type electrode 110.

[0033] Wherein, silicon substrate 101 is the substrate layer of silicon nitride on insulator, thickness is about 725 microns;Silicon dioxide cladding 102 refractive index is about 1.44, as low refractive index material limit the light field in silicon nitride waveguide layer 103, overall thickness is about 5 microns;Silicon nitride waveguide layer 103 cross section size is 150 nanometers x 800 nanometers, can support 380 nanometers to 740 nanometers visible light wavelength single mode transmission;Super surface structure 104 is the periodic subwavelength level hole etched on silicon nitride waveguide layer 103, to realize the regulation of intensity, phase and polarization characteristics in the range of visible light wavelength, its characteristic size is 100 nanometers, less than the shortest wavelength 380 nanometers to be regulated;BCB bonding layer 105 is used to realize the bonding and fixation of silicon nitride device and gallium nitride device, its thickness is about 150 nanometers, and it is transparent to visible light range wavelength.

[0034] Layered cross-sectional view see Figure 2 As shown in Figure 2 The super surface periodic structure is the subwavelength periodic porous structure prepared for the silicon nitride waveguide layer, the shape of the hole can be circular, square, triangular and various shapes, the porous array scale, period and arrangement mode can be diverse, as long as the fine regulation of gallium nitride visible light wavelength range is met.BCB layer is used to complete the bonding and connection of two devices or chips, and it is transparent to visible light wavelength

[0035] In this embodiment, based on the super surface silicon nitride waveguide and gallium nitride visible light source coupling structure, the size of the silicon nitride waveguide can support the single mode transmission of the wavelength range of the gallium nitride visible light source, the periodic super surface structure realizes the high-efficiency coupling of the gallium nitride visible light into the silicon nitride waveguide, the gallium nitride visible light source is a same plane electrode structure, the light is emitted through electric pumping, and the surface incidence transmits through the wavelength transparent BCB material and the silicon dioxide cladding and the super surface structure to interact with each other, and low-loss coupling is realized.

[0036] Finally, it is to be explained that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions, and all should be covered in the scope of the claims of the present application.

Claims

1. A coupling structure of a metasurface-based silicon nitride waveguide and a gallium nitride visible light source, characterized in that: Comprise: a silicon substrate; a silicon dioxide cladding layer on the silicon substrate; a silicon nitride waveguide layer on the silicon dioxide cladding layer, which has a cross-sectional dimension supporting single-mode transmission of visible light wavelengths; a metasurface structure on the silicon nitride waveguide layer, the metasurface structure having periodic sub-wavelength level holes for precise amplitude, phase and polarization control of light in the visible light wavelength range; a BCB bonding layer on the metasurface structure for bonding the silicon nitride waveguide layer with a gallium nitride device; a gallium nitride device comprising: a P-type gallium nitride layer; a gallium nitride multiple quantum well layer on the P-type gallium nitride layer; an N-type gallium nitride layer on the gallium nitride multiple quantum well layer; a P-type electrode on the P-type gallium nitride layer; an N-type electrode on the N-type gallium nitride layer.

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

3. The metasurface-based silicon nitride waveguide and gallium nitride visible light source coupling structure of claim 1, wherein: The BCB bonding layer is used to realize the bonding and fixation of the silicon nitride device and the gallium nitride device, and has a thickness of 150 nanometers and is transparent to visible light wavelengths.

4. The metasurface-based silicon nitride waveguide and gallium nitride visible light source coupling structure of claim 1, wherein: The hole shape of the metasurface structure is circular, square or triangular.

5. The metasurface-based silicon nitride waveguide and gallium nitride visible light source coupling structure of claim 1, wherein: The gallium nitride device is a coplanar electrode structure, and light is emitted through electrical pumping.

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