A micro-ring core cavity and its preparation method and use

Abstract

The present invention relates to a micro-ring core cavity and a preparation method and use thereof. The diameter of the micro-ring core cavity is 400-3000 μm, and the ring core diameter of the micro-ring core cavity is 20-40 μm. The present invention effectively reduces the number of optical modes within an FSR by regulating the size of the micro-ring core cavity, thereby reducing the interaction between optical modes; and the micro-ring core cavity has a high optical quality factor and an excellent dispersion curve, so that the generation of optical solitons becomes possible; the preparation method of the micro-ring core cavity of the present invention adopts step-by-step laser reflux, and the required laser reflux power is low, and the equipment requirements are low.

Description

Technical Field

[0001] The invention belongs to the field of optical microcavities and relates to a micro-ring core cavity and a preparation method and application thereof. Background Art

[0002] Whispering gallery optical microcavities are mainly divided into microdisk cavities, microring core cavities and microsphere cavities (see literature: ML Gorodetsky, AA Savchenkov, and VS Ilchenko, "Ultimate Q of optical microsphere resonators", Opt. Lett. 21, 453 (1996); DW Vernooy, VS Ilchenko, H. Mabuchi, EW Treed, and HJ Kimble, "High-Q measurements of fused-silica microspheres in the near infrared", Opt. Lett. 23, 247 (1998)). Due to their excellent characteristics of high Q value and small mode volume, they are widely used in cavity optomechanics, biodetection, optical frequency comb and other research. In some nonlinear applications, the dispersion of the microcavity is a very important influencing parameter. For example, in an optical comb, the dispersion determines the frequency at the maximum parametric gain and the optical comb bandwidth at a certain pump power. In a microcavity, dispersion is divided into material dispersion and geometric dispersion, which depends on the working wavelength and transverse mode family (see the literature: J. Li, H. Lee, KY Yang, and K. J. Vahala, "Sideband spectroscopy and dispersion measurement in microcavities," Opt. Express 24, 26337 (2012)). The existing micro-ring core cavity has a large ring core diameter and a thick sample thickness, resulting in a large number of modes in the sample. If there are a large number of modes in the ring core, it is inevitable that there will be interactions between the modes, which will affect the generation of some nonlinear phenomena in the microcavity. In theory, the larger the diameter of the microcavity, the less significant the thermal effect and the higher the Q value, which is conducive to the observation of nonlinear effects. When making large-sized samples using the commonly used micro-ring core fabrication method, due to the effect of stress and limited laser power, we usually etch the samples very deeply, which will cause the core diameter of the micro-ring core cavity to be too large, making it impossible to control the dispersion in the cavity well (see reference: T. Chen, H. Lee, and K. Vahala, "Thermal stress in silica-on-silicon disk resonators," Appl. Phys. Lett. 102, 031113 (2013)).

[0003] The number of modes in the micro-ring core cavity also has a great influence on the generation of certain nonlinear phenomena. Due to the presence of a large number of modes in the micro-ring core cavity, the modes will interact with each other, changing the cavity mode dispersion pumped by the optical comb, and thus affecting the generation of the optical comb. Therefore, reducing the number of modes in the micro-ring core cavity and thus reducing the interaction between modes will make it easier to generate optical combs (see the literature: J. Ma, X. Jiang, M. Xiao, "Kerr frequency combs in large-size, ultra-high-Q toroid microcavities with low repetition rates," Photon. Res., 5, 56 (2017)).

[0004] At present, the geometric dispersion is usually controlled by changing the tilt angle of the microdisk cavity. Increasing the tilt angle can effectively control the dispersion. However, since microdisk cavities with large tilt angles are difficult to prepare, and the resulting sidewall smoothness problem has a great impact on the quality of the optical microcavity (see reference: H. Lee, T. Chen, J. Li, KY Yang, S. Jeon, O. Painter, and K. J. Vahala, "Chemically etched ultrahigh-Q wedge-resonator on a silicon chip," Nat. Photonics 6, 369–373 (2012));

[0005] Therefore, it is still of great significance to develop a micro-ring core cavity with high optical quality factor and excellent dispersion curve and its preparation method. Summary of the invention

[0006] The purpose of the present invention is to provide a micro-ring core cavity and a preparation method and use thereof. The diameter of the micro-ring core cavity is 400-3000 μm, and the ring core diameter of the micro-ring core cavity is 20-40 μm. The present invention effectively reduces the number of optical modes within an FSR by regulating the size of the micro-ring core cavity, thereby reducing the interaction between optical modes; and the micro-ring core cavity has a high optical quality factor (Q value) and an excellent dispersion curve; so that the generation of optical solitons becomes possible; the preparation method of the micro-ring core cavity of the present invention adopts step-by-step laser reflux, and the required laser reflux power is low, and the equipment requirements are low.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a micro-ring core cavity, the diameter of which is 400-3000 μm, for example, 420 μm, 440 μm, 460 μm, 480 μm, 500 μm, 700 μm, 900 μm, 1100 μm, 1300 μm, 1500 μm, 1700 μm, 1900 μm, 2100 μm, 2300 μm, 2500 μm, 2700 μm or 2900 μm, etc., and the core diameter of the micro-ring core cavity is 20-40 μm, for example, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 32 μm, 34 μm, 36 μm or 38 μm, etc.

[0009] The size of the micro-ring core cavity of the present invention is controlled to meet the above conditions, and the obtained micro-ring core cavity has a high Q value, and the Q value can reach 4.8×10 8 ; and it has an excellent dispersion curve, and at the same time, the number of optical modes within one FSR is significantly reduced; using the micro-ring core cavity described in the present invention can generate a low threshold optical comb and obtain an optical soliton optical comb.

[0010] Preferably, the diameter of the micro-ring core cavity is 400-500 μm, for example, 410 μm, 420 μm, 430 μm, 440 μm, 450 μm, 460 μm, 470 μm, 480 μm or 490 μm.

[0011] Preferably, the ring core diameter of the micro-ring core cavity is 20-25 μm, such as 21 μm, 22 μm, 23 μm or 24 μm.

[0012] Preferably, the ratio of the diameter of the micro-ring core cavity to the diameter of the ring core of the micro-ring core cavity is (18-22):1, such as 19:1, 20:1 or 21:1.

[0013] Preferably, the thickness of the micro-ring core cavity is less than 12 μm, preferably 6-10 μm, such as 6 μm, 8 μm or 10 μm.

[0014] Preferably, the intrinsic optical Q value of the micro-ring core cavity is 2×10 8 -5×10 8 , for example 3×10 8 , 3.2×10 8 , 3.5×10 8 , 3.8×10 8 , 4×10 8 4.2×10 8 , 4.5×10 8 or 4.8×10 8 wait.

[0015] Preferably, the micro-ring core cavity comprises a circular plane and a circular ring located around the circular plane.

[0016] Preferably, the circular plane and the circular ring are made of crystalline material.

[0017] Preferably, the crystalline material includes any one of silicon dioxide, silicon nitride or arsenic sulfide, or a combination of at least two of them. Exemplary combinations include a combination of silicon dioxide and silicon nitride, a combination of arsenic sulfide and silicon dioxide, or a combination of silicon nitride and arsenic sulfide, etc., preferably silicon dioxide.

[0018] Preferably, the micro-ring core cavity further includes a base for supporting the circular plane.

[0019] Preferably, the material of the base includes any one of Si, SiC or Al2O3 or a combination of at least two of them, and the combination exemplarily includes a combination of Si and SiC, a combination of SiC and Al2O3, or a combination of Si and Al2O3, etc., preferably Si.

[0020] The material of the microfluidic core cavity of the present invention is preferably silicon dioxide, which has relatively low absorption in the 1550nm band, a smooth surface after laser reflow, high cost performance, and easy processing.

[0021] In a second aspect, the present invention provides a method for preparing the micro-ring core cavity as described in the first aspect, the method comprising the following steps:

[0022] (1) coating a photoresist layer on the surface of a crystal material, then exposing, developing, and etching to obtain a circular crystal material layer; one side surface of the crystal material is attached to the surface of a support material;

[0023] (2) dry etching the support material having the circular crystal material layer bonded to the surface in step (1), followed by laser reflow;

[0024] (3) Repeat the operation in step (2) n times, where n is greater than or equal to 1, to obtain the micro-ring core cavity.

[0025] During the process of dry etching the supporting material, part of the crystal material will be suspended in the air. The diameter of the suspended part of the suspended silicon dioxide obtained by etching will also affect the size of the ring core diameter. The less etching, the smaller the ring core diameter, which is conducive to our production of a micro-ring core cavity with a smaller number of intracavity modes. However, the less etching, for the reflow of a large diameter micro-disk cavity, it means that the required laser power is higher, so that the silicon dioxide can be melted; and the preparation method of the micro-ring core cavity of the present invention adopts a step-by-step dry etching and laser reflow method, which can prepare a large diameter and high Q value micro-ring core cavity at a lower laser reflow power, and the preparation process is convenient for controlling the ring core diameter of the micro-ring core cavity, thereby regulating the geometric dispersion of the micro-ring core cavity, and obtaining a micro-ring core cavity with an excellent dispersion curve.

[0026] Preferably, the crystalline material in step (1) comprises any one of silicon dioxide, silicon nitride or arsenic sulfide, or a combination of at least two of them. Exemplary combinations include a combination of silicon dioxide and silicon nitride, a combination of silicon dioxide and arsenic sulfide, or a combination of silicon nitride and arsenic sulfide, etc., preferably silicon dioxide.

[0027] Preferably, the supporting material in step (1) is any one of Si, SiC or Al2O3 or a combination of at least two of them, and the combinations exemplarily include a combination of Si and SiC, a combination of SiC and Al2O3, or a combination of Si and Al2O3, etc., preferably Si.

[0028] Preferably, the thickness of the crystal material in step (1) is 6-10 μm, such as 6 μm, 8 μm or 10 μm.

[0029] The thickness of the crystal material in the preparation process of the micro-ring core cavity described in the present invention is one of the important factors affecting the core diameter of the micro-ring core cavity. The use of the crystal material with the above-mentioned specific thickness in the present invention is more conducive to obtaining a micro-ring core cavity with a smaller core diameter, thereby having a micro-ring core cavity with an excellent dispersion curve.

[0030] Preferably, the diameter of the circular crystalline material layer in step (1) is 2-10 inches, such as 2 inches, 4 inches or 8 inches.

[0031] Preferably, the etching in step (1) is wet etching.

[0032] Preferably, the wet etching method is hydrofluoric acid wet etching.

[0033] Preferably, the etching in step (1) also includes cleaning to remove the photoresist.

[0034] Preferably, the dry etching in step (2) includes XeF2 dry etching.

[0035] Preferably, the laser reflow in step (2) includes CO2 laser reflow.

[0036] Preferably, the power of the laser reflow in step (2) is 30W to 50W, for example, 32W, 34W, 36W, 38W, 40W, 42W, 44W, 46W or 48W.

[0037] Preferably, the dry etching time in step (2) is 1.5-2.5 h, for example, 1.6 h, 1.7 h, 1.8 h, 1.9 h, 2 h, 2.1 h, 2.2 h, 2.3 h or 2.4 h.

[0038] Preferably, the laser reflow time in step (2) is 750-850 milliseconds each time, for example, 760 milliseconds each time, 770 milliseconds each time, 780 milliseconds each time, 790 milliseconds each time, 800 milliseconds each time, 810 milliseconds each time, 820 milliseconds each time, 830 milliseconds each time or 840 milliseconds each time, etc.

[0039] In the preparation process of the micro-ring core cavity described in the present invention, a method of step-by-step dry etching and laser reflow is adopted, wherein the time of a single dry etching and laser reflow is controlled within the above-mentioned range, which is conducive to controlling the micro-ring core cavity with a high Q value and an excellent dispersion curve described in the present invention, and the power required during the laser reflow process is relatively low.

[0040] Preferably, in step (3), n is greater than or equal to 3, for example, 4, 5, 6, 7 or 8.

[0041] As a preferred technical solution of the present invention, the method for preparing the micro-ring core cavity comprises the following steps:

[0042] (1) forming a SiO2 layer on the Si surface, then spin-coating a photoresist on the surface of the SiO2 layer, then exposing, developing, wet-etching with hydrofluoric acid, and cleaning to obtain a circular SiO2 layer;

[0043] (2) performing XeF2 dry etching on the Si with the circular SiO2 layer attached to the surface in step (1), followed by CO2 laser reflow, wherein the power of the CO2 laser reflow is 30-50 W;

[0044] (3) Repeat the operation in step (2) n times, where n is greater than or equal to 1, to obtain the micro-ring core cavity.

[0045] In a third aspect, the present invention provides a use of the micro-ring core cavity as described in the first aspect, wherein the micro-ring core cavity is used to generate a Kerr optical frequency comb and optical solitons.

[0046] In a fourth aspect, the present invention provides a method for controlling dispersion of a micro-ring core cavity, the method comprising using the micro-ring core cavity as described in the first aspect.

[0047] Preferably, the method includes controlling the diameter of the micro-ring core cavity to be 400-3000 μm, for example, 420 μm, 440 μm, 460 μm, 480 μm, 500 μm, 700 μm, 900 μm, 1100 μm, 1300 μm, 1500 μm, 1700 μm, 1900 μm, 2100 μm, 2300 μm, 2500 μm, 2700 μm or 2900 μm, etc., preferably 400-500 μm, and the core diameter of the micro-ring core cavity is 20-40 μm, for example, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 32 μm, 34 μm, 36 μm or 38 μm, etc., preferably 20-25 μm.

[0048] The method of the present invention adjusts the geometric dispersion of the micro-ring core cavity by adjusting the ring core diameter and the diameter of the micro-ring core cavity, and uses the geometric dispersion to compensate for the material dispersion, thereby obtaining an excellent dispersion curve, thereby providing the possibility for the generation of optical solitons.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The diameter of the micro-ring core cavity of the present invention is 400 μm-3000 μm, and the ring core diameter of the micro-ring core cavity is 20-40 μm. By adjusting the size of the micro-ring core cavity, the number of optical modes in one FSR is effectively reduced, thereby reducing the interaction between optical modes;

[0051] (2) The micro-ring core cavity of the present invention has a high optical quality factor and an excellent dispersion curve. The micro-ring core cavity of the present invention can generate a low-threshold optical comb and obtain an optical soliton optical comb;

[0052] (3) The preparation method of the micro-ring core cavity described in the present invention adopts a step-by-step dry etching and laser reflow method, which can prepare a micro-ring core cavity with a high Q value, and can effectively control the core diameter of the micro-ring core cavity, thereby controlling the geometric dispersion of the micro-ring core cavity, and using geometric dispersion to compensate for material dispersion, thereby providing the possibility for the generation of optical solitons. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a cross-sectional view of the micro-ring core cavity of the present invention;

[0054] Figure 2 It is a schematic flow chart of the method for preparing the micro-ring core cavity of the present invention;

[0055] Figure 3 is a dispersion curve diagram of the TE1 mode of the micro-ring core cavity of the present invention under different ring core diameters;

[0056] Figure 4 is a dispersion curve diagram of the TE2 mode of the micro-ring core cavity of the present invention under different ring core diameters;

[0057] Figure 5 It is the mode distribution diagram of the micro-ring core cavity with different ring core diameters obtained by theoretical calculation;

[0058] Figure 6 is an electron microscope image of the micro-ring core cavity prepared in Example 1 of the present invention;

[0059] Figure 7 is the optical mode in the 8FSR of the micro-ring core cavity prepared in Example 1 of the present invention;

[0060] Figure 8 is the optical mode within 1FSR of the micro-ring core cavity prepared in Example 1 of the present invention;

[0061] Fig. 9 is the transmission spectrum of the optical mode of the micro-ring core cavity prepared in Example 1 of the present invention;

[0062] 1-Si, 2-SiO2, 3-photoresist. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0064] The structural schematic diagram of the micro-ring core cavity of the present invention is as follows Figure 1 As shown, the micro-ring core cavity includes a circular plane, a circle of the circular plane is an annular structure, the annular structure is the ring core of the present invention, the cross section of the ring core is circular, and its diameter is the diameter of the ring core of the present invention, the diameter of the ring core is shown as "d" in the figure, the circular plane and the ring core are an integral structure; the diameter of the micro-ring core cavity is shown as "D" in the figure;

[0065] like Figure 1 As shown, the micro-ring core cavity includes a base located below the circular plane for supporting the circular plane. The base is made of Si as an example. It is a necessary structure of the micro-ring core cavity. In addition to supporting SiO2, it can also increase heat dissipation and reduce the influence of thermal effects on nonlinear phenomena.

[0066] The area of ​​the end surface of one side of the base in contact with the circular plane is smaller than the area of ​​the circular plane.

[0067] The preparation process of the micro-ring core cavity of the present invention adopts a step-by-step dry etching and laser reflow method. The crystal material is SiO2 as an example, and the support material is Si as an example. The preparation process is as follows: Figure 2 As shown, the method comprises the following steps:

[0068] (1) forming a SiO2 layer on the Si surface, then spin-coating a photoresist on the surface of the SiO2 layer, then exposing, developing, wet-etching with hydrofluoric acid, cleaning and removing the resist, and obtaining a circular SiO2 layer;

[0069] (2) performing XeF2 dry etching on the Si with the circular SiO2 layer attached to the surface in step (1), followed by CO2 laser reflow;

[0070] (3) Repeat the operation in step (2) n times, where n is greater than or equal to 1, to obtain the micro-ring core cavity.

[0071] The following embodiments all adopt the above process flow chart.

[0072] Example 1

[0073] The diameter of the micro-ring core cavity in this embodiment is 400 μm, the diameter of the core of the micro-ring core cavity is 25 μm, and the thickness of the micro-ring core cavity is 8 μm; its intrinsic optical Q value is 4.8×10 8 ; The material of the micro-ring core cavity is SiO2;

[0074] The preparation method of the micro-ring core cavity described in this embodiment is as follows:

[0075] (1) forming a SiO2 layer on the Si surface, wherein the thickness of the SiO2 layer is 8 μm, and then a layer of S1813 photoresist is spin-coated on the surface of the SiO2 layer, followed by exposure and development to obtain a circular pattern, and then wet-etching with hydrofluoric acid and cleaning to obtain a SiO2 disk with a diameter of 500 μm;

[0076] (2) performing XeF2 dry etching on the Si with the circular SiO2 disk attached to the surface in step (1) for 2 hours, leaving the SiO2 part suspended, and then performing CO2 laser thermal reflow, the laser reflow time is 800 milliseconds each time, and the power of CO2 laser reflow is 40W;

[0077] (3) Repeat the operation in step (2) three times to reach the designed size and obtain the micro-ring core cavity.

[0078] Example 2

[0079] The diameter of the micro-ring core cavity in this embodiment is 3000 μm, the diameter of the core of the micro-ring core cavity is 40 μm, and the thickness of the micro-ring core cavity is 10 μm; the material of the micro-ring core cavity is SiO2;

[0080] The preparation method of the micro-ring core cavity described in this embodiment is as follows:

[0081] (1) forming a SiO2 layer on the Si surface, wherein the thickness of the SiO2 layer is 10 μm, and then spin coating a layer of S1813 photoresist on the surface of the SiO2 layer, and then exposing and developing to obtain a circular pattern, and then wet etching with hydrofluoric acid and cleaning to obtain a SiO2 disk;

[0082] (2) performing XeF2 dry etching on the Si with the circular SiO2 disk attached to the surface in step (1) for 2.5 h, leaving the SiO2 part suspended, and then performing CO2 laser thermal reflow at a power of 50 W;

[0083] (3) Repeat the operation in step (2) 6 times to reach the designed size and obtain the micro-ring core cavity.

[0084] Example 3

[0085] The diameter of the micro-ring core cavity in this embodiment is 500 μm, the diameter of the core of the micro-ring core cavity is 20 μm, and the thickness of the micro-ring core cavity is 6 μm; the material of the micro-ring core cavity is SiO2;

[0086] The preparation method of the micro-ring core cavity described in this embodiment is as follows:

[0087] (1) forming a SiO2 layer on the Si surface, wherein the thickness of the SiO2 layer is 6 μm, and then spin coating a layer of S1813 photoresist on the surface of the SiO2 layer, and then exposing and developing to obtain a circular pattern, and then wet etching with hydrofluoric acid and cleaning to obtain a SiO2 disk;

[0088] (2) performing XeF2 dry etching on the Si with the circular SiO2 disk attached to the surface in step (1) for 1.5 h, leaving the SiO2 part suspended, and then performing CO2 laser thermal reflow at a power of 40 W;

[0089] (3) Repeat the operation in step (2) three times to reach the designed size and obtain the micro-ring core cavity.

[0090] Example 4

[0091] The diameter of the micro-ring core cavity in this embodiment is 450 μm, the diameter of the core of the micro-ring core cavity is 40 μm, and the thickness of the micro-ring core cavity is 8 μm; the material of the micro-ring core cavity is SiO2;

[0092] The preparation method of the micro-ring core cavity described in this embodiment is as follows:

[0093] (1) forming a SiO2 layer on the Si surface, wherein the thickness of the SiO2 layer is 8 μm, and then spin coating a layer of S1813 photoresist on the surface of the SiO2 layer, and then exposing and developing to obtain a circular pattern, and then wet etching with hydrofluoric acid and cleaning to obtain a SiO2 disk;

[0094] (2) performing XeF2 dry etching on the Si with the circular SiO2 disk attached to the surface in step (1) for 1.5 h, leaving the SiO2 part suspended, and then performing CO2 laser thermal reflow at a power of 45 W;

[0095] (3) Repeat the operation in step (2) 4 times to reach the designed size and obtain the micro-ring core cavity.

[0096] Example 5

[0097] The diameter of the micro-ring core cavity in this embodiment is 550 μm, the ring core diameter of the micro-ring core cavity is 30 μm, and the thickness of the micro-ring core cavity is 8 μm; the material of the micro-ring core cavity is SiO2;

[0098] The preparation method of the micro-ring core cavity described in this embodiment is as follows:

[0099] (1) forming a SiO2 layer on the Si surface, wherein the thickness of the SiO2 layer is 8 μm, and then spin coating a layer of S1813 photoresist on the surface of the SiO2 layer, and then exposing and developing to obtain a circular pattern, and then wet etching with hydrofluoric acid and cleaning to obtain a SiO2 disk;

[0100] (2) performing XeF2 dry etching on the Si with the circular SiO2 disk attached to the surface in step (1) for 2 h, leaving the SiO2 part suspended, and then performing CO2 laser thermal reflow at a power of 45 W;

[0101] (3) Repeat the operation in step (2) 4 times to reach the designed size and obtain the micro-ring core cavity.

[0102] Performance Test:

[0103] The present invention utilizes COMSOL The software simulates the dispersion curves of the TE mode of the silica micro-ring core cavity with the same thickness under different ring core diameters, such as Figure 3 and Figure 4 As shown (corresponding to two TE modes, where TE1 is the fundamental transverse electric mode and TE2 is the second-order transverse electric mode); Figure 3 and Figure 4It can be seen that as the diameter of the ring core increases, the dispersion curve becomes flatter and flatter. When the diameter of the ring core increases from 10μm to 20μm, the dispersion changes significantly and the dispersion curve becomes flatter. However, when the diameter of the ring core increases from 20μm to 40μm, the dispersion curve does not change significantly and almost overlaps.

[0104] The present invention simulates the TE mode distribution of the micro-ring core cavity under different ring core diameters, and the simulation results are as follows: Figure 5 As shown by Figure 5 It can be seen that the smaller the diameter of the ring core is, the fewer modes it allows to exist, which is beneficial to avoid interaction between modes.

[0105] The flatter the dispersion curve of the micro-ring core cavity, the more conducive it is to the broadening of the optical soliton spectrum. At the same time, the smaller the core diameter of the micro-ring core cavity, the lower the corresponding Q value, and the steeper the dispersion curve, which is not conducive to the broadening of the optical soliton; therefore, the preferred core diameter of the micro-ring core cavity described in the present invention is 20μm-25μm.

[0106] The electron microscope image of the micro-ring core cavity prepared in Example 1 of the present invention is as follows: Figure 6 As shown by Figure 6 The size and details of the sample can be seen. The optical mode diagrams in 8FSR and 1FSR of the micro-ring core cavity prepared in Example 1 of the present invention are shown in FIG. Figure 7 and Figure 8 As shown by Figure 7 and Figure 8 It can be seen that there are very few optical modes within one FSR and eight FSRs.

[0107] The transmission spectrum of the optical mode of the micro-ring core cavity prepared in Example 1 of the present invention is as follows: Fig. 9 As shown by Fig. 9 The simulation results show that the Q of the optical microcavity is 4.8×10 8 .

[0108] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A micro-ring core cavity, characterized in that: The diameter of the micro-ring core cavity is 400-3000 μm, and the diameter of the ring core of the micro-ring core cavity is 20-40 μm.

2. The micro-ring core cavity according to claim 1, characterized in that: The diameter of the micro-ring core cavity is 400-500 μm.

3. The micro-ring core cavity according to claim 1, characterized in that: The ring core diameter of the micro-ring core cavity is 20-25 μm.

4. The micro-ring core cavity according to claim 1, characterized in that: The ratio of the diameter of the micro-ring core cavity to the diameter of the ring core of the micro-ring core cavity is (18-22):

1.

5. The micro-ring core cavity according to claim 1, characterized in that: The thickness of the micro-ring core cavity is less than 12 μm.

6. The micro-ring core cavity according to claim 1, characterized in that: The thickness of the micro-ring core cavity is 6-10 μm.

7. The micro-ring core cavity according to claim 1, characterized in that: The intrinsic optical Q value of the micro-ring core cavity is 2×10 8 -5×10 8 .

8. The micro-ring core cavity according to claim 1, characterized in that: The micro-ring core cavity comprises a circular plane and a circular ring located around the circular plane.

9. The micro-ring core cavity according to claim 8, characterized in that: The circular plane and the circular ring are made of crystal material.

10. The micro-ring core cavity according to claim 9, characterized in that: The crystalline material includes any one of silicon dioxide, silicon nitride or arsenic sulfide, or a combination of at least two thereof.

11. The micro-ring core cavity according to claim 10, characterized in that: The crystalline material is silicon dioxide.

12. The micro-ring core cavity according to claim 9, characterized in that: The micro-ring core cavity further comprises a base for supporting the circular plane.

13. The micro-ring core cavity according to claim 12, characterized in that: The material of the base includes any one of Si, SiC or Al2O3 or a combination of at least two of them.

14. The micro-ring core cavity according to claim 13, characterized in that: The base is made of Si.

15. The method for preparing a micro-ring core cavity according to any one of claims 1 to 14, characterized in that: The method comprises the following steps: (1) coating a photoresist layer on the surface of a crystal material, then exposing, developing, and etching to obtain a circular crystal material layer; one side surface of the crystal material is attached to the surface of a support material; (2) dry etching the support material having the circular crystal material layer bonded to the surface in step (1), followed by laser reflow; (3) Repeat the operation in step (2) n times, where n is greater than or equal to 1, to obtain the micro-ring core cavity.

16. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The crystalline material in step (1) includes any one of silicon dioxide, silicon nitride or arsenic sulfide, or a combination of at least two of them.

17. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The crystalline material in step (1) is silicon dioxide.

18. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The support material in step (1) is any one of Si, SiC or Al2O3 or a combination of at least two of them.

19. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The supporting material in step (1) is Si.

20. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The thickness of the crystal material in step (1) is 6-10 μm.

21. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The diameter of the circular crystalline material layer in step (1) is 2-10 inches.

22. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The etching in step (1) is wet etching.

23. The method for preparing a micro-ring core cavity according to claim 22, characterized in that: The wet etching method is hydrofluoric acid wet etching.

24. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The etching in step (1) also includes cleaning to remove the photoresist.

25. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The dry etching in step (2) includes XeF2 dry etching.

26. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The laser reflow in step (2) includes CO2 laser reflow.

27. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The power of the laser reflow in step (2) is 30W~50W.

28. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The dry etching time in step (2) is 1.5-2.5 hours.

29. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The laser reflow in step (2) is performed for 750-850 milliseconds each time.

30. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: In step (3), n is greater than or equal to 3.

31. The method for preparing a micro-ring core cavity according to claim 15, characterized in that: The method comprises the following steps: (1) forming a SiO2 layer on the Si surface, then spin-coating a photoresist on the surface of the SiO2 layer, then exposing, developing, wet-etching with hydrofluoric acid, and cleaning to obtain a circular SiO2 layer; (2) performing XeF2 dry etching on the Si with the circular SiO2 layer attached to the surface in step (1), and then performing CO2 laser reflow, wherein the power of the CO2 laser reflow is 30W~50W; (3) Repeat the operation in step (2) n times, where n is greater than or equal to 1, to obtain the micro-ring core cavity.

32. The use of the micro-ring core cavity according to any one of claims 1 to 14, characterized in that: The micro-ring core cavity is used to generate Kerr optical frequency comb and optical solitons.

33. A method for controlling dispersion of a micro-ring core cavity, characterized in that: The method comprises using the micro-ring core cavity as described in any one of claims 1-14.

34. The method for controlling dispersion of a micro-ring core cavity as claimed in claim 33, characterized in that: The method comprises controlling the diameter of the micro-ring core cavity to be 400-3000 μm, and the ring core diameter of the micro-ring core cavity to be 20-40 μm.

35. The method for controlling dispersion of a micro-ring core cavity as claimed in claim 33, characterized in that: The method comprises that the ring core diameter of the micro ring core cavity is 20-25 μm.

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