A high-brightness quantum light source for dense wavelength division multiplexed multi-channel broadcasting

Abstract

This invention discloses a high-brightness quantum light source for dense wavelength division multiplexing (DWDM) multichannel broadcasting, relating to the field of quantum information science and technology. It includes a silicon substrate layer 1; a silicon dioxide layer 2 disposed on the silicon substrate layer 1; and a thin-film lithium niobate device layer 3 disposed on the silicon dioxide layer 2. The thin-film lithium niobate device layer 3 contains a microring resonator 4 and a ridge waveguide 5 for coupling light into the microring resonator 4. The coupling structure between the ridge waveguide 5 and the microring resonator 4 is a sliding rail coupling structure, enabling both near-infrared and visible light to couple with the microring resonator 4 through this coupling structure. The microring resonator 4 has a periodic polarization structure, represented by dark and light stripes in the microring resonator 4. This invention provides a quantum light source that simultaneously satisfies wide bandwidth, ultra-narrow bandwidth, and high brightness, and can generate entangled photon pairs covering multiple DWDM standard channel wavelengths.

Description

Technical Field

[0001] This invention relates to the field of quantum information science and technology, and in particular to a high-brightness quantum light source with dense wavelength division multiplexing multichannel broadcasting. Background Technology

[0002] Quantum information science is a product of the combination of quantum mechanics and information science. It utilizes quantum mechanical systems to achieve new forms of communication, computation, and measurement. Integrating on-chip quantum systems, which miniaturizes and integrates the generation and processing of photonic quantum states onto a chip, has long been a goal pursued by scientists. A fully integrated on-chip quantum system typically includes key components such as quantum light sources, quantum detectors, and quantum transducers. Among these, quantum light sources are fundamental building blocks for realizing quantum networks, essential for both basic understanding and practical applications. The performance parameters of quantum light sources include spectral bandwidth, brightness, and entanglement fidelity. Wide bandwidth, high brightness, and high entanglement fidelity quantum light sources are indispensable components for building quantum networks.

[0003] Entangled photon pairs are typically generated through second- and third-order nonlinear optical processes, including spontaneous parametric downconversion (SPDC) and spontaneous four-wave mixing. Because the third-order nonlinearity of a material is several orders of magnitude smaller than its second-order nonlinearity, the generation rate of entangled photon pairs is generally low in four-wave mixing, making it difficult to generate high-brightness quantum light sources. Furthermore, other third-order nonlinear effects in the material, such as Raman scattering, can affect the four-wave mixing process, thus impacting the generation rate of entangled photon pairs. In contrast, second-order nonlinear processes, due to their stronger nonlinear coefficients, can produce conversion efficiencies several orders of magnitude higher than third-order processes. Moreover, second-order nonlinear processes do not introduce interference from other third-order nonlinearities; therefore, quantum light sources generated through second-order nonlinear processes exhibit superior performance, including high brightness and high entanglement fidelity.

[0004] Compared to other nonlinear materials, lithium niobate possesses strong second-order nonlinearity, a wide transparency window, a large electro-optic coefficient, and excellent photonic integration capabilities, making it one of the most promising materials. In recent years, the emergence of thin-film lithium niobate (TFLN) has further accelerated the development of integrated optics. Thin-film lithium niobate not only retains the excellent physical properties of lithium niobate but also allows for the fabrication of integrated optical structures with small mode fields using photolithography and etching techniques. This enables the localization of light at the micro- and nano-scale, significantly improving nonlinear conversion efficiency and making it an ideal platform for generating quantum light sources. Currently, quantum light sources based on TFLN nanowaveguide structures have achieved brightness levels of 10⁻⁶. 6 Hz / mW 2 The brightness can reach the GHz level. Even higher brightness can be achieved using microcavity resonators.

[0005] Microcavity resonators (MCRs) are optical structures that confine light within a cavity using total internal reflection to form a stable traveling wave transmission mode. Due to the small mode volume and longer light-matter interaction length within a MCR, higher nonlinear conversion efficiency and a greater generation rate of entangled photon pairs can be achieved. Because of the resonant modes, the entangled photons generated by MCRs are discrete, and the high quality factor (Q) characteristic results in narrow linewidth entangled photons, eliminating the need for subsequent filtering with narrow linewidth filters in quantum network construction. However, reported quantum light sources based on MCRs suffer from narrow bandwidth and incompatibility with ITU channels, hindering their practical application in quantum networks.

[0006] In summary, despite some outstanding research based on the TFLN platform, achieving high-quality multi-wavelength quantum light sources compatible with ITU-T high-density wavelength division multiplexing (HDWDM) multichannel networks across wide communication bands remains a challenge. Further research on the generation and manipulation of quantum light sources based on cavity-enhanced SPDC is an essential requirement for realizing large-scale quantum technologies. Summary of the Invention

[0007] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to design a quantum light source that simultaneously satisfies wide bandwidth, ultra-narrow bandwidth, high brightness, and can generate entangled photon pairs covering multiple DWDM standard channel wavelengths.

[0008] To achieve the above objectives, the present invention provides a high-brightness quantum light source for dense wavelength division multiplexing multichannel broadcasting, comprising: a silicon substrate layer 1; a silicon dioxide layer 2 disposed on the silicon substrate layer 1; a thin-film lithium niobate device layer 3 disposed on the silicon dioxide layer 2, wherein the thin-film lithium niobate device layer 3 is provided with a micro-ring resonant cavity 4 and a ridge waveguide 5 for coupling light into the micro-ring resonant cavity 4; The coupling structure between the ridge waveguide 5 and the microring resonator 4 is a sliding rail coupling structure, so that both near-infrared light and visible light can be coupled to the microring resonator 4 through this coupling structure; the microring resonator 4 has a periodic polarization structure, which is represented by the dark and light stripes in the microring resonator 4.

[0009] In a preferred embodiment of the present invention, the height of the microring resonator 4 is on the order of hundreds of nanometers and the width is on the order of micrometers; the height and width of the ridge waveguide 5 are both on the order of hundreds of nanometers.

[0010] In a preferred embodiment of the present invention, the thickness of the silicon substrate layer 1 is 500 micrometers; the thickness of the silicon dioxide layer 2 is 2 micrometers; and the thin-film lithium niobate device layer 3 is a Z-cut thin-film lithium niobate with a thickness of 520 nanometers.

[0011] In a preferred embodiment of the present invention, the microring resonant cavity 4 has a height of 320 nanometers, a width of 1.55 micrometers, and an etching angle of 60°; the ridge waveguide 5 has a height of 320 nanometers and a width of 850 nanometers; and the sliding rail coupling structure has a coupling interval of 500 nanometers and a coupling length of 67 micrometers.

[0012] In a preferred embodiment of the present invention, the light in the microring resonator 4 propagates in the fundamental mode, and the phase matching method selected for the frequency doubling and spontaneous parametric downconversion processes in the microring resonator 4 is OOOE type phase matching.

[0013] In a preferred embodiment of the present invention, the radius of the micro-ring resonant cavity 4 is 201.8 micrometers.

[0014] In a preferred embodiment of the present invention, the FSR of the micro-ring resonator 4 is designed to be 100 GHz to match the ITU-T WDM standard channel.

[0015] In a preferred embodiment of the present invention, the polarization period of the periodic polarization structure is 6.62 micrometers.

[0016] The present invention also provides a method for preparing the above-mentioned high-brightness quantum light source for dense wavelength division multiplexing multichannel broadcasting, comprising the following steps: Step 1: Hydrogen ions are injected into a lithium niobate crystal parallel to the cleavage plane to form a thin film layer. The lithium niobate crystal layer with hydrogen ions injected is bonded to a silicon dioxide layer 2 by crystal bonding technology. The silicon dioxide layer 2 is deposited on a silicon substrate layer 1. The thin film lithium niobate device layer 3 is formed by annealing and peeling, and then annealing and chemical mechanical polishing are performed. Step 2: Define the micro-ring resonator 4 and ridge waveguide 5 on the thin-film lithium niobate device layer 3 by electron beam lithography, transfer the pattern to the thin-film lithium niobate layer by dry etching, and then remove the residue by wet etching. Step 3: Define the periodic polarized electrode structure on the thin-film lithium niobate device layer 3 again using electron beam photolithography with electron beam photoresist, and evaporate the metal to form the electrode; Step 4: Polarize the micro-ring resonator 4, and apply high voltage to cause domain inversion in the part covered by the electrodes, forming a periodic domain inversion structure; Step 5: Polish the two end faces of the ridge waveguide 5 and perform input and output optical coupling through a lens fiber.

[0017] Preferably, in step 3, the evaporated metal is 10 nanometer titanium and 70 nanometer gold; in step 4, the polarization temperature is 260°C.

[0018] Technical effect

[0019] This invention offers highly practical solutions. Based on a cavity-enhanced SPDC process, it significantly improves the generation rate of entangled photon pairs. Furthermore, due to the high Q-value of the microcavity, the generated entangled photons have narrow linewidths, eliminating the need for narrow-linewidth filters in practical applications, thus increasing integration density and reducing costs. Through the design of the microring resonator structure, the near-infrared dispersion within the cavity is flattened, and broadband entangled photon pair generation is achieved using the OEE phase-matching condition. The generated entangled photon pairs have a linewidth of 438.8 MHz and a brightness of 1.86 × 10⁻⁶. 9 Hz / mW 2 / GHz; the designed micro-ring resonator has an FSR of 100 GHz, which meets the ITU DWDM wavelength standard and can distribute SPDC photon pairs to multiple channels in the full DWDM band.

[0020] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0021] Figure 1 This is a structural diagram of a high-brightness quantum light source according to a preferred embodiment of the present invention; Figure 2 This is a structural parameter analysis diagram of the microring resonator according to a preferred embodiment of the present invention; Figure 3 These are structural diagrams and analytical diagrams of a preferred embodiment of the slide rail type coupling structure of the present invention; Figure 4 This is an analysis diagram of the operating mode and quasi-phase matching conditions of the microring resonator according to a preferred embodiment of the present invention; Figure 5 This is a photon pair performance analysis diagram of a preferred embodiment of the present invention; Figure 6 This is a photon pair generation rate analysis diagram in a preferred embodiment of the present invention; In the figure: 1. Silicon substrate layer; 2. Silicon dioxide layer; 3. Thin-film lithium niobate device layer; 4. Micro-ring resonator; 5. Ridge waveguide. Detailed Implementation

[0022] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0023] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0024] refer to Figures 1-6 This invention provides a high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting, comprising: a silicon substrate layer 1; a silicon dioxide layer 2 disposed on the silicon substrate layer 1; and a thin-film lithium niobate device layer 3 disposed on the silicon dioxide layer 2. The silicon substrate layer 1, silicon dioxide layer 2, and thin-film lithium niobate device layer 3 are stacked sequentially to form a three-layer structure, achieving good optical confinement. The thin-film lithium niobate device layer 3 is provided with a micro-ring resonant cavity 4 and a ridge waveguide 5 for coupling light into the micro-ring resonant cavity 4. The coupling structure between the ridge waveguide 5 and the microring resonator 4 is a sliding rail coupling structure, so that both near-infrared light and visible light can be coupled to the microring resonator 4 through this coupling structure; the microring resonator 4 has a periodic polarization structure, which is represented by the dark and light stripes in the microring resonator 4.

[0025] In a preferred embodiment of the present invention, the height of the microring resonator 4 is on the order of hundreds of nanometers and the width is on the order of micrometers; the height and width of the ridge waveguide 5 are both on the order of hundreds of nanometers.

[0026] In a preferred embodiment of the present invention, the thickness of the silicon substrate layer 1 is 500 micrometers; the thickness of the silicon dioxide layer 2 is 2 micrometers; and the thin-film lithium niobate device layer 3 is a Z-cut thin-film lithium niobate with a thickness of 520 nanometers.

[0027] In a preferred embodiment of the present invention, the microring resonator 4 has a height of 320 nm, a width of 1.55 μm, and an etching angle of 60°; the ridge waveguide 5 has a height of 320 nm and a width of 850 nm; the sliding rail coupling structure has a coupling gap of 500 nm and a coupling length of 67 μm. The parameters of the slide rail type coupling structure are as follows: Figure 3 As shown, light at 1550 nm and 775 nm can be coupled into the microring resonator 4 through the sliding rail coupling structure under the specified parameters. Compared with the prior art, which uses two coupling waveguides to couple light of different wavelengths, this design has a higher degree of integration.

[0028] In a preferred embodiment of the present invention, the light in the microring resonator 4 propagates in the fundamental mode. In order to obtain a multi-wavelength quantum light source, the phase matching method selected for the frequency doubling (SHG) and spontaneous parametric down-conversion (SPDC) processes in the microring resonator 4 is ooe-type phase matching, that is, the fundamental frequency light in the SHG process is TE. 00 The mode, frequency-doubled light is TM 00 In the SPDC process, the pump light is TM. 00 The mode produces signal light and idler light in TE bands. 00 Pattern. For example... Figure 2 As shown, the selected structural parameters are due to the fact that under these structural parameters, the near-infrared band TE 00 Second-order group velocity dispersion of the mode for It has small group velocity dispersion and flat dispersion in the near-infrared band, which is conducive to the generation of multi-wavelength entangled photon pairs.

[0029] In a preferred embodiment of the present invention, the radius of the microring resonator 4 is 201.8 micrometers. This radius is determined by formula after the parameters of the microring resonator 4 are determined. Received, among which The center wavelength, The group refractive index of the microring at the center wavelength. Let be the radius of the micro-ring.

[0030] In a preferred embodiment of the present invention, the free spectral range (FSR) of the micro-ring resonator 4 is designed to be 100 GHz to match the ITU DWDM standard channel.

[0031] The micro-ring resonator 4 design makes the waveguide dispersion flat in the near-infrared band. By using the cascaded frequency doubling (SHG) / spontaneous parametric down-conversion (SPDC) process and OOOe phase matching, a tunable, efficient, broadband, high-quality microcavity-enhanced SPDC is generated, producing ultra-narrowband, high-brightness photons, which can eliminate the need for narrowband filters required in quantum network applications.

[0032] This invention utilizes the SHG / SPDC cascade process to generate entangled photon pairs. The cascade process ensures that the pump light from the SPDC process is exactly the desired TM. 00 The visible light mode. The SHG / SPDC cascade process involves two second-order nonlinear processes. The input fundamental frequency light undergoes an SHG process to generate frequency-doubled light, which serves as the pump light for the SPDC process, further generating a signal light and an idler light. A signal photon and an idler photon form an entangled photon pair. Achieving a high-efficiency SHG / SPDC cascade process requires that the light involved satisfy energy and momentum conservation conditions. Energy conservation requires… , in the formula The angular frequency of the fundamental light. The angular frequency of the generated frequency-doubled light. The angular frequency of the signal light generated during the SPDC process. Let be the angular frequency of the idler light generated during the SPDC process. Momentum conservation requires that the phase-matching condition be satisfied, i.e. , m is the number of angular patterns for the corresponding pattern.

[0033] This invention utilizes quasi-phase matching technology, introducing a periodic domain structure through domain inversion via an applied electric field to periodically modulate the nonlinear polarizability. This provides a reciprocal compensation for the phase mismatch between the fundamental and harmonic optical modes (which is also the phase mismatch between the pump, signal, and idler light during SPDC). Figure 4 As shown, according to the formula The polarization period was found to be 6.62 micrometers.

[0034] The present invention also provides a method for preparing the above-mentioned high-brightness quantum light source for dense wavelength division multiplexing multichannel broadcasting, comprising the following steps: Step 1: Hydrogen ions are injected parallel to the cleavage plane in a lithium niobate crystal to form a thin film layer. The hydrogen-injected lithium niobate crystal layer is bonded to a silicon dioxide layer 2 using crystal bonding technology. The silicon dioxide layer 2 is deposited on a silicon substrate layer 1. Defects are created in the ion-implanted layer by annealing, thereby peeling it off to form a thin film lithium niobate device layer 3. Annealing is then performed to reduce damage to the crystal caused by ion implantation. Finally, chemical mechanical polishing is used to reduce the surface roughness of the thin film lithium niobate device layer 3. In a preferred embodiment, the thickness of the silicon substrate layer 1 is 500 micrometers; the thickness of the silicon dioxide layer 2 is 2 micrometers; and the thickness of the thin film lithium niobate device layer 3 is preferably 520 nanometers, but other parameter settings that achieve the desired effect can also be used. Step 2: Define the micro-ring resonator 4 and ridge waveguide 5 on the thin-film lithium niobate device layer 3 by electron beam lithography, transfer the pattern to the thin-film lithium niobate layer by dry etching, and then remove the residue by wet etching. Step 3: Again, define the periodic polarized electrode structure on the thin-film lithium niobate device layer 3 using electron beam photolithography and evaporate the metal to form the electrode. In a preferred embodiment, 10 nanometer titanium and 70 nanometer gold are evaporated using electron beam evaporation technology. The 10 nanometer titanium is used to increase the adhesion of the gold. After that, the electrode structure required for polarization is obtained by peeling. Step 4: Polarize the micro-ring resonant cavity 4. Place the sample on an aluminum sheet and heat it to 260°C on a hot plate. Connect the positive electrode of the high voltage source to the gold electrode through a probe and connect the negative electrode to the aluminum sheet to form a circuit. By applying high voltage, the part covered by the gold electrode will undergo domain inversion, forming a periodic domain inversion structure, thus completing the polarization. Step 5: Polish the two end faces of the ridge waveguide 5 and perform input and output optical coupling through a lens fiber.

[0035] In this invention, a high-brightness quantum light source is achieved by utilizing the cavity-enhanced SHG / SPDC cascade process on the upper cavity of a thin-film lithium niobate device layer 3, combined with the strong second-order nonlinear coefficient of lithium niobate and the enhanced light-matter interaction of a micro-ring resonator 4. The high Q-factor resonator provides a narrow linewidth transmission spectrum at the resonant wavelength, resulting in narrow-linewidth and high-brightness entangled photon pairs. This eliminates the need for narrowband filters in waveguide-based quantum light sources, leading to high integration. The micro-ring resonator 4 structure is designed to achieve flat dispersion in the visible light band. Ooe-type quasi-phase matching ensures that the SHG and SPDC processes meet phase-matching conditions, generating broadband entangled photon pairs in the visible light band. The radius of the micro-ring resonator 4 is designed to achieve an FSR of 100 GHz, meeting the ITU DWDM standard channel wavelength, allowing the photon pairs generated by SPDC to be distributed to multiple wavelength channels in the optical network.

[0036] In an embodiment of the present invention, the fundamental frequency light wavelength used in the SHG / SPDC cascade process is 1538.248 nm, corresponding to ITU DWDM standard channel CH48. It is generated by a tunable laser, passes through an erbium-doped fiber amplifier and a fiber polarization controller, and is coupled to the ridge waveguide 5 via a single-mode lens fiber using end-face coupling. Then, it is coupled to the micro-ring resonator 4 through the ridge waveguide 5.

[0037] Preliminary tests were conducted on embodiments of the present invention, such as... Figure 5 As shown, the microring resonator 4 in this embodiment of the invention is a high Q-factor microcavity, with Q values ​​of 2.10 M, 1.03 M, and 1.12 M at wavelengths of 1537.432 nm (CH47), 1538.248 nm (CH48), and 1539.050 nm (CH49), respectively. The Q value at a visible light wavelength of 769.124 nm is 1.71 M.

[0038] like Figure 5 As shown, the photons generated in this embodiment of the invention can cover ITU DWDM standard channels CH20-CH60, corresponding to a wavelength range of 1527-1563 nm. The coincidence count rate between channels CH36-CH47 and CH49-CH60 was tested, indicating that coincidence counts only exist between wavelength-related photon pairs. Since photons exist in pairs, photons will also be generated in the short wavelength region below 1527 nm, theoretically generating a photon bandwidth of 76 nm, corresponding to 28 photon pairs. Compared with previous work, this invention generates more photon pairs and has a wider bandwidth.

[0039] like Figure 6 As shown, in this embodiment of the invention, the photon pair generation rate of channels CH47-CH49 is 817 MHz / mW, corresponding to a linewidth of 438.8 MHz and a luminance of 1.86 × 10⁻⁶. 9 Hz / mW 2 / GHz. Compared to previous work, the entangled photon pairs generated by this invention have higher brightness.

[0040] The embodiments of the present invention exhibit excellent performance, enabling the generation of entangled photon pairs with wide bandwidth, narrow linewidth, and high brightness, corresponding to the ITU DWDM standard channel wavelength, thus meeting design requirements.

[0041] The process technology used in this invention includes electron beam lithography, dry etching, electron beam evaporation of metal and periodic polarization, which are mature processes in the prior art. The waveguide end face combined with the mode converter can realize the packaging of the device, and finally obtain an integrated high-quality multi-wavelength quantum light source device.

[0042] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting, characterized in that, include: Silicon substrate (1); A silicon dioxide layer (2) is disposed on the silicon substrate layer (1); A thin-film lithium niobate device layer (3) is disposed on the silicon dioxide layer (2), and a micro-ring resonator (4) and a ridge waveguide (5) for coupling light into the micro-ring resonator (4) are disposed in the thin-film lithium niobate device layer (3). The coupling structure between the ridge waveguide (5) and the micro-ring resonator (4) is a sliding rail coupling structure, so that near-infrared light and visible light can be coupled to the micro-ring resonator (4) through the coupling structure. The micro-ring resonator (4) has a periodic polarization structure, which is represented by the dark and light stripes in the micro-ring resonator 4.

2. The high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 1, characterized in that, The height of the micro-ring resonator (4) is in the hundreds of nanometers and the width is in the micrometers; the height and width of the ridge waveguide (5) are both in the hundreds of nanometers.

3. The high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 2, characterized in that, The silicon substrate layer (1) has a thickness of 500 micrometers; the silicon dioxide layer (2) has a thickness of 2 micrometers; and the thin-film lithium niobate device layer (3) is a Z-cut thin-film lithium niobate with a thickness of 520 nanometers.

4. The high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 3, characterized in that, The microring resonant cavity (4) has a height of 320 nanometers, a width of 1.55 micrometers, and an etching angle of 60°; the ridge waveguide (5) has a height of 320 nanometers and a width of 850 nanometers; the sliding rail coupling structure has a coupling interval of 500 nanometers and a coupling length of 67 micrometers.

5. The high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 4, characterized in that, In the micro-ring resonator (4), light propagates in the fundamental mode, and the phase matching method selected for the frequency doubling and spontaneous parametric downconversion process in the micro-ring resonator (4) is OOO-type phase matching.

6. The high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 5, characterized in that, The radius of the micro-ring resonant cavity (4) is 201.8 micrometers.

7. The high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 6, characterized in that, The micro-ring resonator (4) is designed with an FSR of 100 GHz to match the ITU DWDM standard channel.

8. The high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 7, characterized in that, The polarization period of the periodic polarization structure is 6.62 micrometers.

9. A method for preparing a high-brightness quantum light source with dense wavelength division multiplexing and multichannel broadcasting as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Step 1: Hydrogen ions are injected into the lithium niobate crystal parallel to the cleavage plane to form a thin film layer. The lithium niobate crystal layer with hydrogen ions injected is bonded to the silicon dioxide layer (2) by crystal bonding technology. The silicon dioxide layer (2) is deposited on the silicon substrate layer (1). The thin film lithium niobate device layer (3) is formed by annealing and peeling, and then annealing and chemical mechanical polishing are performed. Step 2: Define the micro-ring resonator (4) and ridge waveguide (5) on the thin film lithium niobate device layer (3) by electron beam photolithography, transfer the pattern to the thin film lithium niobate layer by dry etching, and then remove the residue by wet etching; Step 3: Again, use electron beam photolithography to define the periodic polarized electrode structure on the thin film lithium niobate device layer (3) with electron beam photoresist, and evaporate the metal to form the electrode; Step 4: Polarize the micro-ring resonator (4) and apply high voltage to cause domain reversal in the part covered by the electrode, forming a periodic domain reversal structure; Step 5: Polish the two end faces of the ridge waveguide (5) and perform input and output optical coupling through a lens fiber.

10. The method for preparing a high-brightness quantum light source with dense wavelength division multiplexing and multi-channel broadcasting as described in claim 9, characterized in that, In step 3, the evaporated metals are 10 nanometer titanium and 70 nanometer gold; in step 4, the polarization temperature is 260℃.

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