Suspension micro-ring resonator based on three-dimensional printing and preparation method thereof

Abstract

The invention relates to the technical field of optical devices, in particular to a three-dimensional printing-based suspended micro-ring resonator and a preparation method thereof. The suspended micro-ring resonator sequentially comprises a substrate, a base and a device main body from bottom to top, and the device main body comprises a micro-ring resonant cavity and a coupling waveguide coupled with the micro-ring resonant cavity; and the micro-ring resonant cavity and the coupling waveguide are suspended on the base through supporting pieces to form a suspended echo wall mode so as to improve the mechanical resonance effect. The suspension micro-ring resonator can enhance the mechanical response of the micro-cavity to ultrasonic waves by utilizing the mechanical resonance effect of the suspension micro-ring resonator in the optical micro-cavity, so that the sensitivity is further improved. By using the suspended echo wall mode micro-ring cavity, the mechanical resonance effect can be improved, and the ultrasonic sensitivity is further improved. In addition, the design of the suspended micro-ring resonator reduces the contact with a support structure or a substrate, thereby reducing the influence of heat and mechanical noise, and further improving the sensitivity and resolution of the sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of optical devices, and more specifically, to a suspended microring resonator based on three-dimensional printing and a preparation method thereof. Background Art

[0002] With the rapid development of optical communication technology and the continuous progress of integrated optical technology in recent years, optical microring resonators, as an important optical component, have shown broad application prospects in the fields of optical signal processing, optical communication, biosensing, etc. Optical microring resonators have the advantages of simple structure, high quality factor, small size and easy integration, which can effectively reduce the design cost of optical systems and improve the overall performance of the system.

[0003] Optical microring resonators play a vital role in promoting the development of optical sensing and other related fields, but their performance is mainly determined by factors such as their structural parameters, material properties, and preparation process. In terms of structural design, vertically coupled resonators face the problem of uneven surface of each layer in a multilayer structure, which may increase the loss of the device and offset the advantages of using a vertically coupled structure. Although the racetrack structure can improve the coupling efficiency by increasing the length of the straight waveguide, it may also cause mode mismatch loss due to the mode mismatch between the straight waveguide and the curved waveguide. In terms of process, the coupling length between the coupled waveguide and the microring waveguide is very small, and usually only when the waveguide spacing is very small can a sufficiently large coupling be generated, and the coupling efficiency is very sensitive to the coupling spacing, which places high demands on the accuracy of ordinary photolithography technology. Although more advanced photolithography technology can meet the requirements, it is more expensive. At the same time, when etching the waveguide, it is also necessary to pay attention to ensuring the verticality and smoothness of the waveguide sidewalls.

[0004] The structural design of optical microring resonators needs to consider many factors, such as wavelength, refractive index, coupling length, coupling spacing, etc. In terms of device structure processing, the microring device structure processed by traditional photolithography technology is single. If you want to achieve sensor device sensitivity enhancement and increase the sensitivity of the device, you need to etch and hollow out the substrate of the device, or make an additional surface film sensitivity enhancement structure. The preparation process of this process is complex, the requirements for photolithography accuracy and etching accuracy are high, and the yield rate is low. Summary of the invention

[0005] In order to overcome the defects in the above-mentioned prior art, the present invention provides a suspended microring resonator based on three-dimensional printing, which effectively improves the performance of the resonator; and provides a preparation method of a suspended microring resonator based on three-dimensional printing, which effectively improves the preparation efficiency and yield rate.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A suspended microring resonator based on three-dimensional printing comprises, from bottom to top, a substrate, a base and a device body, wherein the device body comprises a microring resonant cavity and a coupling waveguide coupled to the microring resonant cavity; the microring resonant cavity and the coupling waveguide are both suspended on the base through a support member to form a suspended whispering gallery mode to enhance the mechanical resonance effect.

[0008] According to the above technical means, the substrate and base of the present invention are used to support the device body, and the microring resonant cavity and the coupled waveguide are suspended on the base. The microring resonant cavity uses the interference phenomenon of light waves in the microring structure to realize the regulation of light waves and the detection of weak signals. The microring resonator has a very high quality factor (Q value), which means that they can store light energy in a very narrow frequency range, and thus are very sensitive to the frequency changes of light waves. At the same time, the microring resonator confines the light field to a very small volume through a waveguide, which increases the chance of interaction between light and matter, thereby improving the sensitivity of the sensor. The coupled waveguide is used to introduce the optical signal into the microring resonant cavity for coupling, and to lead the coupled optical signal out of the microring resonant cavity. The suspended microring resonator can enhance the mechanical response of the microcavity to ultrasound by using its mechanical resonance effect (i.e., using the microcavity optical force system) in the optical microcavity, thereby further improving the sensitivity. The use of a suspended whispering gallery mode microring cavity can enhance the mechanical resonance effect, thereby improving the ultrasonic sensitivity.

[0009] In one embodiment, the support member is a thin sheet structure with a thickness of 0.3um to 1um. The support member is set as a thin sheet structure, which can further increase its mechanical resonance effect.

[0010] In one embodiment, a support member located at the bottom of the microring resonant cavity is provided with a plurality of notches at intervals along the circumference of the microring; cracks for limiting the transmission of light along the base are provided at both ends of the base, and the cracks are located on both sides of the microring resonant cavity. The notches can prevent the light signal from propagating along the support member. The cracks are provided on both sides of the base to prevent the light from being transmitted along the base, thereby ensuring the transmission of light along the microring resonant cavity.

[0011] In one embodiment, the structure of the microring resonant cavity is a circular ring waveguide, and the structure of the coupling waveguide is a pulley waveguide.

[0012] In one embodiment, the support member at the bottom of the microring resonant cavity has the same structure as the microring resonant cavity, i.e., a ring structure; the support member at the bottom of the coupling waveguide has the same structure as the coupling waveguide, i.e., a strip structure. The support member is arranged along the bottom of the microring resonant cavity, the microring resonant cavity is a ring structure, and the support member is also a ring structure; similarly, the support member at the bottom of the coupling waveguide, the coupling waveguide is a strip, and the support member is arranged at the bottom of the coupling waveguide along the length direction of the coupling waveguide; since the support member is in the form of a thin sheet, it is preferred that the support member is arranged in the middle of the bottom, so that a more stable support can be provided.

[0013] In one of the embodiments, the width of the circular waveguide is 2um to 4um, and the height is 2um to 4um; the width of the coupled waveguide is 1.5um to 2.5um, and the height is 2um to 4um; the coverage angle of the pulley waveguide is 28 to 35 degrees; the spacing between the coupling area of ​​the coupled waveguide and the microring resonant cavity is 0.6um to 1.1um; and the height of the support member is 2um to 3um.

[0014] In one of the embodiments, the refractive index of the base and the device body is higher than the refractive index of the substrate.

[0015] In one of the embodiments, the materials of the base, the support and the device body include IP-DIP photoresist, IP-DIP2 photoresist, IP-L photoresist, IP-S photoresist, IP-G photoresist or IP-n162 photoresist; the material of the substrate includes a quartz sheet, and the refractive index at a wavelength of 780nm is 1.38 to 1.55.

[0016] In one of the embodiments, the base, the support member and the device body are integrally formed by three-dimensional printing.

[0017] The present invention also provides a method for preparing a microring resonator, comprising the following steps:

[0018] S1. Use 3D drawing software to create a three-dimensional model of the suspended microring resonator, import it into the processing software of the three-dimensional laser printing device, set the three-dimensional printing parameters of the structure, and export the printing file;

[0019] S2. Place a clean substrate into the sample holder, fix it with tape, and drop photoresist on the substrate;

[0020] S3. Assemble the high numerical aperture objective lens and the sample holder into the three-dimensional laser printing device;

[0021] S4. Load the print file, use the optical imaging system to identify and locate the upper surface of the substrate, focus the laser through the objective lens, and print the suspended microring resonator structure in conjunction with the precision displacement platform;

[0022] S5. Take out the substrate sheet, place it on a vertical cleaning rack, immerse it in a developer and an isopropanol solution in turn, remove the uncured photoresist, and obtain the suspended microring resonator according to any one of claims 1 to 9.

[0023] At present, in order to achieve the sensitivity enhancement of the sensor device, the preparation of optical microring resonators requires the deposition of surface thin film sensitivity enhancement structures or the etching and hollowing of the device substrate. The preparation process of this process is complex, the requirements for photolithography accuracy and etching accuracy are high, and the yield is low. The preparation method of the suspended microring resonator proposed in the present invention is based on three-dimensional laser printing, and its resolution can reach the sub-micron level, which can ensure the needs of high-precision manufacturing. At the same time, the structure can be prepared on the substrate in one step, which greatly improves the preparation efficiency and has the advantages of high precision, high speed and high flexibility.

[0024] Compared with the prior art, the beneficial effects are:

[0025] 1. The present invention proposes a suspended microring resonator based on 3D printing. The suspended microring resonator can enhance the mechanical response of the microcavity to ultrasound by using its mechanical resonance effect in an optical microcavity, thereby further improving the sensitivity. The use of a suspended whispering gallery mode microring cavity can enhance the mechanical resonance effect, thereby improving the ultrasonic sensitivity. In addition, the design of the suspended microring resonator reduces the contact with the supporting structure or substrate, thereby reducing the impact of thermal and mechanical noise, further improving the sensitivity and resolution of the sensor;

[0026] 2. The preparation method of the suspended microring resonator proposed in the present invention is based on three-dimensional laser printing, and its resolution can reach sub-micron level, which can ensure the needs of high-precision manufacturing. At the same time, the structure can be prepared on the substrate in one step, which greatly improves the preparation efficiency and has the advantages of high precision, high speed and high flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the microring resonator of the present invention from the first perspective.

[0028] Figure 2 It is a schematic diagram of the overall structure of the microring resonator of the present invention from a second viewing angle.

[0029] Figure 3 It is a schematic structural diagram of the device body of the present invention.

[0030] Figure 4 It is a schematic diagram of the structure of the microring resonant cavity of the present invention.

[0031] Figure 5 It is a schematic diagram of the structure of the support member and the micro-ring resonant cavity of the present invention. Figure numerals: 1. substrate; 2. base; 3. microring resonator; 4. coupled waveguide; 5. support; 6. notch; 7. crack. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The present invention is described in one of the embodiments in combination with the specific implementation methods. Among them, the drawings are only used for exemplary descriptions, and only schematic diagrams are shown, not physical drawings, and cannot 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 the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0033] In the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it 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 operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for exemplary explanations and cannot be understood as limiting the present invention. For ordinary technicians in the field, the specific meanings of the above terms can be understood according to specific circumstances. In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text is to include three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that satisfy both A and B.

[0034] Embodiment 1:

[0035] like Figure 1 and Figure 2 As shown, a suspended microring resonator based on three-dimensional printing includes, from bottom to top, a substrate 1, a base 2 and a device body, wherein the device body includes a microring resonant cavity 3 and a coupling waveguide 4 coupled to the microring resonant cavity 3; the microring resonant cavity 3 and the coupling waveguide 4 are both suspended on the base 2 through a support 5 to form a suspended whispering gallery mode to enhance the mechanical resonance effect.

[0036] According to the above technical means, the substrate 1 and base 2 of the present invention are used to support the device body, and the microring resonant cavity 3 and the coupling waveguide 4 are suspended on the base 2. The microring resonant cavity 3 uses the interference phenomenon of light waves in the microring structure to realize the regulation of light waves and the detection of weak signals. The microring resonator has a very high quality factor (Q value), which means that they can store light energy in a very narrow frequency range, and are very sensitive to the frequency changes of light waves. At the same time, the microring resonator confines the light field to a very small volume through a waveguide, which increases the opportunity for light to interact with matter, thereby improving the sensitivity of the sensor. The coupling waveguide 4 is used to introduce the optical signal into the microring resonant cavity 3 for coupling, and to lead the coupled optical signal out of the microring resonant cavity 3. The suspended microring resonator can enhance the mechanical response of the microcavity to ultrasound by using its mechanical resonance effect (i.e., using the microcavity optical force system) in the optical microcavity, thereby further improving the sensitivity. The use of a suspended whispering gallery mode microring cavity can enhance the mechanical resonance effect, thereby improving the ultrasonic sensitivity.

[0037] like Figures 3 to 5 As shown, the support member 5 is a thin sheet structure with a thickness of 0.3um to 1um. The support member 5 is set as a thin sheet structure, which can further increase its mechanical resonance effect.

[0038] like Figure 3 As shown, the support member 5 located at the bottom of the microring resonant cavity 3 is provided with a plurality of notches 6 at intervals along the circumference of the microring; cracks 7 for limiting the transmission of light along the base 2 are respectively provided at both ends of the base 2, and the cracks 7 are located on both sides of the microring resonant cavity 3. The notches 6 can prevent the optical signal from propagating along the support member 5. The cracks 7 are provided on both sides of the base 2 to prevent the light from being transmitted along the base 2, thereby ensuring the light is transmitted along the microring resonant cavity 3.

[0039] In this embodiment, if Figure 2 and Figure 3 As shown, the structure of the microring resonant cavity 3 is a circular waveguide, and the structure of the coupling waveguide 4 is a pulley waveguide. The support member 5 located at the bottom of the microring resonant cavity 3 has the same structure as that of the microring resonant cavity 3, which is a ring structure; the support member 5 located at the bottom of the coupling waveguide 4 has the same structure as that of the coupling waveguide 4, which is a long strip structure. The support member 5 is arranged along the bottom of the microring resonant cavity 3, the microring resonant cavity 3 is a circular ring structure, and the support member 5 is also a circular ring structure; similarly, the support member 5 located at the bottom of the coupling waveguide 4, the coupling waveguide 4 is a long strip, and the support member 5 is arranged at the bottom of the coupling waveguide 4 along the length direction of the coupling waveguide 4; since the support member 5 is in the form of a thin sheet, it is preferred that the support member 5 is arranged in the middle of the bottom, so that it can provide more stable support.

[0040] In this embodiment, the width of the circular waveguide is 2um~4um, and the height is 2um~4um; the width of the coupling waveguide 4 is 1.5um~2.5um, and the height is 2um~4um, and the coverage angle of the pulley waveguide is 28~35 degrees; the spacing between the coupling area of ​​the coupling waveguide 4 and the microring resonant cavity 3 is 0.6um~1.1um; the height of the support member 5 is 2um~3um.

[0041] In this embodiment, the refractive index of the base 2 and the device body is higher than the refractive index of the substrate 1 .

[0042] In one of the embodiments, the materials of the base 2, the support 5 and the device body include IP-DIP photoresist, IP-DIP2 photoresist, IP-L photoresist, IP-S photoresist, IP-G photoresist or IP-n162 photoresist; the material of the substrate 1 includes a quartz sheet, and the refractive index at a wavelength of 780nm is 1.38 to 1.55.

[0043] In this embodiment, the base 2, the support member 5 and the device body are integrally formed by three-dimensional printing.

[0044] Embodiment 2:

[0045] The other structures of this embodiment are the same as those of Embodiment 1, except that, in this embodiment, the base 2, the support member 5, and the device body are made of polymer material; and the refractive index of the polymer material is higher than that of the substrate 1 material.

[0046] Embodiment 3:

[0047] The present invention also provides a method for preparing a microring resonator, comprising the following steps:

[0048] S1. Use 3D drawing software to create a three-dimensional model of the suspended microring resonator, import it into the processing software of the three-dimensional laser printing device, set the three-dimensional printing parameters of the structure, and export the printing file;

[0049] S2. Place a clean substrate 1 into the sample holder, fix it with tape, and drop photoresist on the substrate 1;

[0050] S3. Assemble the high numerical aperture objective lens and the sample holder into the three-dimensional laser printing device;

[0051] S4. Load the print file, use the optical imaging system to identify and locate the upper surface of substrate 1, focus the laser through the objective lens, and print the suspended microring resonator structure in conjunction with the precision displacement platform;

[0052] S5. Take out a substrate, place it on a vertical cleaning rack, and immerse it in a developer and an isopropanol solution in turn to remove the uncured photoresist to obtain the suspended microring resonator described in Example 1.

[0053] At present, in order to achieve the sensitivity enhancement of the sensor device, the preparation of optical microring resonators requires the deposition of a surface thin film sensitivity enhancement structure or the etching and hollowing out of the substrate 1 of the device. The preparation process of this process is complex, the requirements for photolithography accuracy and etching accuracy are high, and the yield is low. The preparation method of the suspended microring resonator proposed in the present invention is based on three-dimensional laser printing, and its resolution can reach the sub-micron level, which can ensure the needs of high-precision manufacturing. At the same time, the structure can be prepared on the substrate 1 in one step, which greatly improves the preparation efficiency and has the advantages of high precision, high speed and high flexibility.

[0054] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0055] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A suspended microring resonator based on three-dimensional printing, characterized in that: The device comprises, from bottom to top, a substrate (1), a base (2) and a device body, wherein the device body comprises a microring resonant cavity (3) and a coupling waveguide (4) coupled to the microring resonant cavity (3); the microring resonant cavity (3) and the coupling waveguide (4) are both suspended on the base (2) via a support (5) to form a suspended whispering gallery mode, thereby improving the mechanical resonance effect.

2. The suspended microring resonator based on three-dimensional printing according to claim 1, characterized in that: The support member (5) is a thin sheet structure with a thickness of 0.3 um to 1 um.

3. The suspended microring resonator based on three-dimensional printing according to claim 2, characterized in that: A support member (5) located at the bottom of the microring resonant cavity (3) is provided with a plurality of notches (6) spaced apart along the circumference of the microring; cracks (7) for limiting the transmission of light along the base (2) are respectively provided at both ends of the base (2), and the cracks (7) are located on both sides of the microring resonant cavity (3).

4. The suspended microring resonator based on three-dimensional printing according to claim 3, characterized in that: The structure of the micro-ring resonant cavity (3) is a circular ring waveguide, and the structure of the coupling waveguide (4) is a pulley waveguide.

5. The suspended microring resonator based on three-dimensional printing according to claim 4, characterized in that: The support member (5) located at the bottom of the microring resonant cavity (3) has the same structure as the microring resonant cavity (3), and is a ring-shaped structure; the support member (5) located at the bottom of the coupling waveguide (4) has the same structure as the coupling waveguide (4), and is a long strip-shaped structure.

6. The suspended microring resonator based on three-dimensional printing according to claim 4, characterized in that: The width of the circular waveguide is 2um to 4um, and the height is 2um to 4um; the width of the coupling waveguide (4) is 1.5um to 2.5um, and the height is 2um to 4um; the coverage angle of the pulley waveguide is 28 to 35 degrees; the spacing between the coupling region of the coupling waveguide (4) and the microring resonant cavity (3) is 0.6um to 1.1um; and the height of the support member (5) is 2um to 3um.

7. The suspended microring resonator based on three-dimensional printing according to any one of claims 1 to 6, characterized in that: The refractive index of the base (2) and the device body is higher than the refractive index of the substrate (1).

8. The suspended microring resonator based on three-dimensional printing according to claim 7, characterized in that: The materials of the base (2), the support (5) and the device body include IP-DIP photoresist, IP-DIP2 photoresist, IP-L photoresist, IP-S photoresist, IP-G photoresist or IP-n162 photoresist; the material of the substrate (1) includes a quartz sheet, and the refractive index at a wavelength of 780 nm is 1.38 to 1.

55.

9. The suspended microring resonator based on three-dimensional printing according to claim 7, characterized in that: The base (2), the support member (5) and the device body are integrally formed by three-dimensional printing.

10. A method for preparing a microring resonator according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Use 3D drawing software to create a three-dimensional model of the suspended microring resonator, import it into the processing software of the three-dimensional laser printing device, set the three-dimensional printing parameters of the structure, and export the printing file; S2. Place a clean substrate (1) into a sample holder, fix it with tape, and drop photoresist on the substrate (1); S3. Assemble the high numerical aperture objective lens and the sample holder into the three-dimensional laser printing device; S4. Load the print file, use the optical imaging system to identify and locate the upper surface of the substrate (1), focus the laser through the objective lens, and print the suspended microring resonator structure with the precision displacement platform; S5. Take out the substrate (1), place it on a vertical cleaning rack, immerse it in a developer and an isopropanol solution in turn, remove the uncured photoresist, and obtain the suspended microring resonator according to any one of claims 1 to 9.

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