Integrated platform for exciting molecular fluorescence signal

Abstract

The invention provides an integrated platform for exciting a molecular fluorescence signal, which comprises an input optical coupling structure, a first filtering structure, a light beam splitting tree structure, a filtering structure array, a fluorescence excitation structure array and an optical coupling structure array which are arranged in sequence, an integrated fluorescence excitation scheme is provided for detection of biological sample fluorescence signals. Compared with a traditional excitation scheme, the on-chip filter is introduced, wide-spectrum background light composed of spontaneous radiation fluorescence of laser or waveguide can be reduced, and therefore shot noise is reduced, and the signal-to-noise ratio and the signal background ratio can be better improved.

Description

Technical Field

[0001] The invention belongs to the technical field of biochips and relates to an integrated platform for exciting molecular fluorescence signals. Background Art

[0002] Biochip technology is a comprehensive high-tech technology that involves biology, chemistry, medicine, precision machining, optics, microelectronics, informatics and other fields. It is a hot topic with strong interdisciplinary nature. In recent years, the excitation and collection of biological fluorescence signals through optical integrated chips have gradually shown important value and potential in the field of fluorescent molecule detection, especially in the field of single-molecule fluorescence detection.

[0003] This technology uses semiconductor processes to achieve a monolithic integrated solution from fluorescence signal excitation, fluorescence signal collection to fluorescence signal detection. By generating nanoscale sample restriction sites on a large scale on the chip surface and combining biochemical modification methods, spatial restriction at the single-molecule scale is achieved. In addition, compared to the traditional optical system method of exciting and collecting fluorescence signals, this technology uses an evanescent field to excite fluorescence through an optical waveguide, achieving simultaneous excitation of large-flux sites, and using the on-chip collection structure to make the sample restriction sites correspond to the detection pixels, achieving simultaneous collection of fluorescence signals at large-flux sites, and ultimately achieving fluorescence detection at large-flux sites.

[0004] However, the effectiveness of this technology is highly dependent on the detection performance of a specific fluorescent signal. The signal-to-noise ratio and signal-to-background ratio are used to evaluate the fluorescence detection performance. How to improve the signal-to-noise ratio and signal-to-background ratio has become the key to improving the detection performance of the fluorescent signal. As for noise, in addition to the noise related to the photodetector, it also includes shot noise. Shot noise is often greater than the noise of the photodetector. Increasing fluorescence or suppressing background light can improve the signal-to-noise ratio and signal-to-background ratio. In addition to the scattered excitation light, there is other light with a wider spectrum in the background light. These wide-spectrum background lights mainly come from the spontaneous radiation of the laser and the spontaneous radiation of the optical waveguide material. Since the fluorescence signal of the molecule, especially the single-molecule-level fluorescence signal intensity is very weak, it is particularly important to suppress the background light. Although the excitation light can be filtered out by a filter, how to suppress the wide-spectrum background light still needs to be solved.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an integrated platform for exciting molecular fluorescence signals, so as to solve the problem of low signal-to-noise ratio and signal-to-background ratio of existing biochips.

[0007] To achieve the above objectives and other related objectives, the present invention provides an integrated platform for exciting molecular fluorescence signals, comprising:

[0008] An input optical coupling structure is used to couple the laser light emitted by an off-chip laser into the chip;

[0009] A first filtering structure, wherein the input end of the first filtering structure is connected to the output end of the input light coupling structure, and is used to allow incident laser light of a certain wavelength to pass through and block the background fluorescence of the laser's spontaneous radiation;

[0010] An optical beam splitting tree structure, wherein an input end of the optical beam splitting tree structure is connected to an output end of the first filtering structure, and is used to split one input light into multiple output lights and form multiple output ends;

[0011] A filter structure array, comprising a plurality of second filter structures, wherein the input ends of the plurality of second filter structures are connected one-to-one with the plurality of output ends of the light beam splitting tree structure, and are used to allow incident laser light of a certain wavelength to pass through and block the spontaneous radiation background fluorescence of the waveguide material;

[0012] A fluorescence excitation structure array, comprising a plurality of fluorescence excitation structures, wherein input ends of the plurality of fluorescence excitation structures are connected one-to-one with output ends of the plurality of second filtering structures, and are used to confine the physical space of the fluorescent molecules and excite the fluorescent molecules to generate fluorescent radiation;

[0013] The light outcoupling structure array comprises a plurality of light outcoupling structures, wherein the input ends of the plurality of light outcoupling structures are connected one by one with the output ends of the plurality of fluorescence excitation structures, and are used for coupling out the remaining excitation light after passing through the fluorescence excitation structure array.

[0014] Optionally, the input light coupling structure comprises a waveguide grating coupler or an edge coupler, and a 3dB line width of the input light coupling structure is greater than 10nm.

[0015] Optionally, the first filtering structure includes one of a micro-ring filter, a waveguide grating filter and a cascaded directional coupler structure filter, and the second filtering structure includes a waveguide grating filter or a cascaded directional coupler structure.

[0016] Optionally, the waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a straight waveguide and a groove array, wherein the groove array includes a plurality of rectangular grooves arranged in sequence and at equal intervals along the length direction of the straight waveguide, the length direction of the rectangular groove is perpendicular to the length direction of the straight waveguide and the length of the rectangular groove is equal to the width of the straight waveguide, the rectangular groove opens from the upper surface of the straight waveguide and the depth of the rectangular groove is less than the thickness of the straight waveguide, and the rectangular groove is filled with a dielectric material, and the refractive index of the dielectric material is different from the refractive index of the straight waveguide.

[0017] Optionally, the waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a straight waveguide and a groove array, the groove array includes a plurality of groove groups arranged in sequence and at equal intervals along the length direction of the straight waveguide, the groove group includes a first groove and a second groove spaced apart in the width direction of the straight waveguide, the first groove and the second groove are both opened from the upper surface of the straight waveguide and the depths of the first groove and the second groove are both less than the thickness of the straight waveguide, the opposite ends of the first groove and the second groove respectively pass through the side surfaces of the straight waveguide, the first groove and the second groove are both filled with dielectric material, and the refractive index of the dielectric material is different from that of the straight waveguide.

[0018] Optionally, the waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a straight waveguide and an island structure array, the island structure array includes a plurality of island structure groups arranged in sequence and at equal intervals along the length direction of the straight waveguide, the island structure group includes a first island structure and a second island structure arranged at intervals in the width direction of the straight waveguide, the first island structure and the second island structure are distributed on opposite sides of the straight waveguide and are symmetrically arranged about the straight waveguide axis, and the thickness of the first island structure and the second island structure are both equal to the thickness of the straight waveguide.

[0019] Optionally, the waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a waveguide main body and a wing array, the waveguide main body includes a first straight waveguide, a second straight waveguide and a third straight waveguide connected in sequence along a specified direction, the width of the first straight waveguide and the third straight waveguide are the same and greater than the width of the second straight waveguide, the wing array includes a first wing and a second wing arranged along the width direction of the second straight waveguide, the first wing and the second wing are connected to opposite sides of the second straight waveguide and are symmetrically arranged about the axis of the second straight waveguide, and the thickness of the first wing and the second wing are both equal to the thickness of the second straight waveguide.

[0020] Optionally, the working light source wavelength band range of the first filtering structure is 400nm-800nm, and the working light source wavelength band range of the second filtering structure is 400nm-800nm.

[0021] Optionally, the light splitting tree structure splits one path of input light into multiple paths of output light according to the same splitting ratio.

[0022] Optionally, the optical beam splitting tree structure includes one or more optical beam splitter units, and the optical beam splitter unit includes one or more of a Y-branch structure, a 2×2 directional coupler, a 1×2 multimode interference coupler, a 2×2 multimode interference coupler, a 1×3 multimode interference coupler and a 1×5 multimode interference coupler.

[0023] Optionally, the fluorescence excitation structure includes a cladding and a waveguide structure coated in the cladding, and the surface of the cladding above the waveguide structure is provided with sample wells arranged at a certain period along the waveguide propagation direction, and the sample wells are used to load molecular substances that can excite fluorescence, and the distance between the bottom surface of the sample well and the top surface of the waveguide structure is less than the evanescent wave penetration distance of the waveguide structure.

[0024] Optionally, the waveguide structure adopts a straight waveguide, and the sample well is located directly above the straight waveguide; or the waveguide structure includes a straight waveguide and a plurality of grating structures located on one side of the straight waveguide and connected to the straight waveguide, and the sample well is located directly above the grating structure; or the waveguide structure includes a straight waveguide and a V-shaped metal grating structure located on the straight waveguide, and the sample well is located directly above the V-shaped metal grating structure.

[0025] Optionally, the light outcoupling structure adopts a grating coupler, and the 3dB line width of the light outcoupling structure is greater than 10nm.

[0026] As described above, the integrated platform for exciting molecular fluorescence signals of the present invention includes an input light coupling structure, a first filtering structure, a light beam splitting tree structure, a filtering structure array, a fluorescence excitation structure array and a light coupling structure array arranged in sequence, providing an integrated fluorescence excitation scheme for the detection of fluorescence signals of biological samples. Compared with the traditional excitation scheme, the present invention introduces an on-chip filter, which can reduce the wide-spectrum background light composed of spontaneous radiation fluorescence of laser or waveguide, thereby reducing shot noise, which is more conducive to improving the signal-to-noise ratio and signal-to-background ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shown is a schematic structural diagram of an integrated platform for exciting molecular fluorescence signals according to the present invention.

[0028] Figure 2A schematic diagram of an edge coupler used in an input light coupling structure in one embodiment is shown.

[0029] Figure 3 A schematic diagram of a grating coupler used in an input light coupling structure in another embodiment is shown.

[0030] Figure 4 FIG. 1 is a schematic diagram showing the structure of a micro-ring filter used in a first filtering structure in an embodiment.

[0031] Figure 5 Shown is a top view of a waveguide distributed Bragg reflector used in a first filtering structure in one embodiment.

[0032] Figure 6 Display as Figure 5 Side view of the structure shown.

[0033] Figure 7 Shown is a top view of another waveguide distributed Bragg reflector used in the first filtering structure in one embodiment.

[0034] Figure 8 Display as Figure 7 Side view of the structure shown.

[0035] Fig. 9 Shown is a top view of yet another waveguide distributed Bragg reflector used in the first filtering structure in one embodiment.

[0036] Fig.10 Display as Fig. 9 Side view of the structure shown.

[0037] Fig.11 Shown is a top view of yet another waveguide distributed Bragg reflector used in the first filtering structure in one embodiment.

[0038] Fig.12 Display as Fig.11 Side view of the structure shown.

[0039] Fig.13 Shown is a schematic structural diagram of a cascaded directional coupler structure filter used in a first filtering structure in an embodiment.

[0040] Fig.14 Schematic diagram of the structure showing a Y-branched structure.

[0041] Fig.15 Shown is a schematic diagram of the structure of a 1×2 multimode interference coupler.

[0042] Fig.16 Shown is a schematic diagram of the structure of a 2×2 multimode interference coupler.

[0043] Fig.17 Shown is a schematic diagram of the structure of a 2×2 directional coupler.

[0044] Fig.18 Shown is a schematic diagram of the structure of a 1×5 multimode interference coupler.

[0045] Fig.19 Shown is a schematic diagram of the structure of a 1×3 multimode interference coupler.

[0046] Fig. 20 Shown is a schematic diagram of the structure of a 1×N optical beam splitter unit.

[0047] Fig.21 Shown is a schematic side view of a fluorescent excitation structure array in one embodiment.

[0048] Fig. 22 Display as Fig.21 Top view of the structure shown.

[0049] Fig.23 Display as Fig.21 Another side view of the structure shown.

[0050] Fig.24 Shown is a schematic side view of the fluorescent excitation structure array in another embodiment.

[0051] Fig.25 Display as Fig.24 Top view of the structure shown.

[0052] Fig.26 Shown is a schematic side view of the fluorescent excitation structure array in yet another embodiment.

[0053] Fig. 27 Display as Fig.26 Top view of the structure shown.

[0054] Description of Reference Numerals

[0055] 1 Input optical coupling structure

[0056] 101 Edge Coupler

[0057] 102 Grating Coupler

[0058] 2 First filter structure

[0059] 201 Waveguide

[0060] 202 First Micro Ring

[0061] 203 Second Micro Ring

[0062] 211, 221, 231 straight waveguide

[0063] 212, 222 groove array

[0064] 213 rectangular groove

[0065] 232 island structure array

[0066] 241 waveguide body

[0067] 2411 First Straight Waveguide

[0068] 2412 Second straight waveguide

[0069] 2413 Third straight waveguide

[0070] 242 Flanking Array

[0071] 251 First Directional Coupler

[0072] 252 Second directional coupler

[0073] 3 Light beam splitting tree structure

[0074] 301 Beam Splitter Unit

[0075] 4 Filter structure array

[0076] 401 Second filter structure

[0077] 5 Fluorescence excitation structure array

[0078] 501 Fluorescence Excitation Structure

[0079] 502 cladding

[0080] 503 Waveguide Structure

[0081] 5031, 5033 straight waveguide

[0082] 5032 Grating Structure

[0083] 5034 V-type metal grating structure

[0084] 504 sample wells

[0085] 6 Optical coupling structure array

[0086] 601 Optical coupling structure

[0087] 7.9 External optical fiber

[0088] 8.10 Straight waveguide DETAILED DESCRIPTION

[0089] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0090] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components.

[0091] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0092] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the schematic diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0093] For ease of description, spatially relative terms such as "under", "below", "below", "below", "above", "on", etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0094] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0095] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0096] See also Figure 1, which is a schematic diagram of the structure of the integrated platform for exciting molecular fluorescence signals of the present invention, including an input light coupling structure 1, a first filtering structure 2, a light beam splitting tree structure 3, a filtering structure array 4, a fluorescence excitation structure array 5 and a light coupling-out structure array 6 which are arranged in sequence.

[0097] Specifically, the integrated platform for exciting molecular fluorescence signals of the present invention exists in the form of a chip, and the input light coupling structure 1 is used to couple the laser light emitted by the laser outside the chip into the chip.

[0098] As an example, the input light coupling structure 1 adopts a waveguide grating coupler or an edge coupler, and the 3dB line width of the input light coupling structure is greater than 10nm.

[0099] As an example, see Figure 2 , which is a schematic diagram of an edge coupler 101 used in the input light coupling structure 1 in an embodiment, wherein the edge coupler 101 adopts an inverted tapered waveguide structure, the tip of the inverted tapered waveguide structure is located at the edge of the chip, the off-chip optical fiber 7 is aligned with the tip of the inverted tapered waveguide structure, and the widened end of the inverted tapered waveguide structure is connected to a straight waveguide 8.

[0100] As an example, see Figure 3 , shown is a schematic diagram of a grating coupler 102 used in the input light coupling structure 1 in another embodiment, wherein the off-chip optical fiber 9 is aligned with the grating coupler 102 nearly perpendicular to the chip surface, and the tail end of the grating coupler 102 is connected to a straight waveguide 10.

[0101] Specifically, the input end of the first filtering structure 2 is connected to the output end of the input light coupling structure 1, and is used to allow incident laser light of a certain wavelength to pass through and block the spontaneous radiation background fluorescence of the laser. That is, the first filtering structure 2 can filter out the component of the laser in the fluorescence band.

[0102] As an example, the working light source wavelength band of the first filtering structure 2 is in the range of 400nm to 800nm.

[0103] As an example, the first filtering structure 2 may adopt one of a microring filter, a waveguide grating filter and a cascaded directional coupler structure filter, wherein the microring filter may be implemented by a single microring structure or a multi-microring cascade, and the waveguide grating filter may adopt a waveguide distributed Bragg reflector.

[0104] As an example, see Figure 4, which is a schematic diagram of the structure of a micro-ring filter used in the first filtering structure 2 in an embodiment, includes a waveguide 201 and a first micro-ring 202 and a second micro-ring 203 coupled to the waveguide 201, wherein the desired filtering effect can be achieved by optimizing parameters such as the micro-ring radius, the waveguide width, and the spacing between the waveguide and the micro-ring.

[0105] As an example, see Figure 5 and Figure 6 ,in, Figure 5 It is a top view of a waveguide distributed Bragg reflector used in the first filtering structure 2 in one embodiment, Figure 6 Display as Figure 5 A side view of the structure shown, wherein the waveguide distributed Bragg reflector includes a straight waveguide 211 and a groove array 212, the groove array 212 includes a plurality of rectangular grooves 213 arranged in sequence and at equal intervals along the length direction of the straight waveguide 211, the length direction of the rectangular groove 213 is perpendicular to the length direction of the straight waveguide 211 and the length of the rectangular groove 213 is equal to the width of the straight waveguide 211, the rectangular groove 213 opens from the upper surface of the straight waveguide 211 and the depth of the rectangular groove is less than the thickness of the straight waveguide 211, and the rectangular groove can be selectively filled with a dielectric material, and the refractive index of the dielectric material is different from the refractive index of the straight waveguide 211.

[0106] As an example, the groove array 212 can be formed on the surface of the straight waveguide 211 by a shallow etching process, and the morphology after etching is alternating rectangles, thereby achieving a periodic change in the refractive index difference.

[0107] As an example, see Figure 7 and Figure 8 ,in, Figure 7 FIG. 2 is a top view of another waveguide distributed Bragg reflector used in the first filtering structure 2 in one embodiment. Figure 8 Display as Figure 7A side view of the structure shown, wherein the waveguide distributed Bragg reflector includes a straight waveguide 221 and a groove array 222, the groove array 222 includes a plurality of groove groups arranged in sequence and at equal intervals along the length direction of the straight waveguide 221, the groove group includes a first groove and a second groove spaced apart in the width direction of the straight waveguide 221, the first groove and the second groove are both opened from the upper surface of the straight waveguide 221 and the depths of the first groove and the second groove are both less than the thickness of the straight waveguide, the opposite ends of the first groove and the second groove respectively penetrate the side surfaces of the straight waveguide 221, the first groove and the second groove can be selectively filled with dielectric material, and the refractive index of the dielectric material 3 is different from that of the straight waveguide 221.

[0108] As an example, the groove array 222 can be formed on the surface of the straight waveguide by a shallow etching process, and the morphology after etching is fishbone-like, which can also achieve periodic changes in the refractive index difference.

[0109] As an example, see Fig. 9 and Fig.10 ,in, Fig. 9 It is a top view of another waveguide distributed Bragg reflector used in the first filtering structure 2 in one embodiment, Fig.10 Display as Fig. 9 A side view of the structure shown, wherein the waveguide distributed Bragg reflector includes a straight waveguide 231 and an island structure array 232, the island structure array 232 includes a plurality of island structure groups arranged in sequence and at equal intervals along the length direction of the straight waveguide 231, the island structure group includes a first island structure and a second island structure arranged at intervals in the width direction of the straight waveguide 231, the first island structure and the second island structure are distributed on opposite sides of the straight waveguide 231 and are symmetrically arranged about the axis of the straight waveguide 231, and the thickness of the first island structure and the second island structure are both equal to the thickness of the straight waveguide 231.

[0110] As an example, the island structure array 232 can be formed on both sides of the straight waveguide 231 by a full etching process to achieve a periodic change in the refractive index difference.

[0111] As an example, see Fig.11 and Fig.12 ,in, Fig.11 FIG. 2 is a top view of another waveguide distributed Bragg reflector used in the first filtering structure 2 in one embodiment. Fig.12 Display as Fig.11A side view of the structure shown, wherein the waveguide distributed Bragg reflector includes a waveguide body 241 and a wing array 242, the waveguide body 241 includes a first straight waveguide 2411, a second straight waveguide 2412 and a third straight waveguide 2413 connected in sequence along a specified direction, the width of the first straight waveguide 2411 and the third straight waveguide 2413 are the same and greater than the width of the second straight waveguide 2412, the wing array 242 includes a first wing and a second wing arranged along the width direction of the second straight waveguide 2411, the first wing and the second wing are connected to opposite sides of the second straight waveguide 2412 and are symmetrically arranged about the second straight waveguide axis 2412, and the thickness of the first wing and the second wing are both equal to the thickness of the second straight waveguide 2412.

[0112] As an example, the side wing array 242 can be formed on both sides of the second straight waveguide 2412 by a full etching process, and the morphology after etching is herringbone-shaped, realizing a periodic change in the refractive index difference, wherein the ends of the first side wing and the second side wing can protrude relatively from the sides of the first straight waveguide 2411 and the third straight waveguide 2413.

[0113] As an example, see Fig.13 , which is a schematic structural diagram of a cascaded directional coupler structure filter adopted by the first filtering structure 2 in an embodiment, and includes a cascaded first directional coupler 251 and a second directional coupler 252. The desired filtering effect can be achieved by designing the coupling length, coupling spacing and other parameters of the first directional coupler 251 and the second directional coupler 252.

[0114] Specifically, the input end of the light splitting tree structure 3 is connected to the output end of the first filtering structure 2, which is used to split one input light into multiple output lights and form multiple output ends, so that the input light is split into more branches to facilitate the subsequent expansion of fluorescence excitation points.

[0115] As an example, the light splitting tree structure 3 splits one path of input light into multiple paths of output light according to the same splitting ratio.

[0116] As an example, the optical splitting tree structure 3 includes one or more optical splitter units 301, and the optical splitter unit includes one or more of a Y-branch structure, a 2×2 directional coupler, a 1×2 multimode interference coupler, a 2×2 multimode interference coupler, a 1×3 multimode interference coupler and a 1×5 multimode interference coupler.

[0117] As an example, see Figures 14 to 20 , showing various exemplary structures of the optical beam splitter unit, wherein, Fig.14 A schematic diagram showing a Y-branched structure. Fig.15Shown is a schematic diagram of the structure of a 1×2 multimode interference coupler. Fig.16 Shown is a schematic diagram of the structure of a 2×2 multimode interference coupler. Fig.17 Shown is a schematic diagram of the structure of a 2×2 directional coupler. Fig.18 Shown is a schematic diagram of the structure of a 1×5 multimode interference coupler. Fig.19 Shown is a schematic diagram of the structure of a 1×3 multimode interference coupler. Fig. 20 Shown is a schematic diagram of the structure of a 1×N optical beam splitter unit.

[0118] Specifically, the filter structure array 4 includes multiple second filter structures 401, and the input ends of the multiple second filter structures 401 are connected one-to-one with the multiple output ends of the light beam splitting tree structure 3, so as to allow incident laser of a certain wavelength to pass through and block the spontaneous radiation background fluorescence of the waveguide material.

[0119] As an example, the working light source wavelength band of the second filtering structure 401 is in the range of 400nm to 800nm.

[0120] As an example, the second filtering structure 401 may adopt a waveguide grating filter or a cascaded directional coupler structure, wherein the waveguide grating filter may adopt a waveguide distributed Bragg reflector, such as the aforementioned Figure 5 and Figure 6 , Figure 7 and Figure 8 , Fig. 9 and Fig.10 ,or Fig.11 and Fig.12 The waveguide distributed Bragg reflector structure shown in the figure or other suitable structures, the cascaded directional coupler structure can adopt the aforementioned Fig.13 The structure shown or other suitable structure.

[0121] Specifically, the fluorescence excitation structure array 5 includes multiple fluorescence excitation structures 501, and the input ends of the multiple fluorescence excitation structures 501 are connected one-to-one with the output ends of the multiple second filtering structures 401, which are used to limit the physical space of fluorescent molecules and excite fluorescent molecules to generate fluorescent radiation.

[0122] Specifically, the fluorescence excitation structure 501 excites fluorescence through the waveguide evanescent wave light field.

[0123] As an example, see Fig.21 , Fig. 22 and Fig.23 , which is a schematic diagram of the structure of the fluorescence excitation structure array 5 in one embodiment, wherein: Fig.21 is a side view, Fig. 22 is a top view (the cladding is omitted), Fig.23The fluorescence excitation structure array 5 includes a cladding 502 and a waveguide structure 503 coated in the cladding 502. The surface of the cladding 502 above the waveguide structure 503 is provided with sample wells 504 arranged at a certain period along the waveguide propagation direction. The sample wells 504 are used to load molecular substances that can excite fluorescence. The distance between the bottom surface of the sample wells 504 and the top surface of the waveguide structure 503 is less than the waveguide evanescent wave penetration distance.

[0124] As an example, the waveguide structure 503 adopts a straight waveguide, and the sample well 504 is located directly above the straight waveguide.

[0125] As an example, the sample well 504 may be in the shape of a cylinder, a truncated cone, a cuboid or other suitable shapes, and the size (eg, diameter, side length, etc.) of the sample well 504 may be in the order of tens to hundreds of nanometers.

[0126] As an example, fluorescent molecules are fixed to the bottom of the sample well 504 by a chemical surface modification method, so as to be excited by the waveguide evanescent wave light field and generate fluorescent signals.

[0127] As an example, see Fig.24 and Fig.25 , which is a schematic diagram of the structure of the fluorescence excitation structure array 5 in another embodiment, wherein: Fig.24 is a side view, Fig.25 It is a top view (cladding omitted), the waveguide structure 503 includes a straight waveguide 5031 and a plurality of grating structures 5032 located on one side of the straight waveguide 5031 and connected to the straight waveguide 5031 , and the sample well 504 is located directly above the grating structure 5032 .

[0128] As an example, see Fig.26 and Fig. 27 , which is a schematic diagram of the structure of the fluorescence excitation structure array 5 in another embodiment, wherein: Fig.26 is a side view, Fig. 27 It is a top view (with the cladding omitted), the waveguide structure 503 includes a straight waveguide 5033 and a V-shaped metal grating structure 5034 located on the straight waveguide 5033 , and the sample well 504 is located directly above the V-shaped metal grating structure 5034 .

[0129] Specifically, the optical outcoupling structure array 6 includes a plurality of optical outcoupling structures 601, and the input ends of the plurality of optical outcoupling structures 601 are connected one-to-one with the output ends of the plurality of fluorescent excitation structures 501, so as to couple out the remaining excitation light after passing through the fluorescent excitation structure array 5 to prevent echo reflection.

[0130] As an example, the light out-coupling structure 601 adopts a grating coupler, and the 3dB line width of the light out-coupling structure 601 is greater than 10nm.

[0131] In summary, the integrated platform for exciting molecular fluorescence signals of the present invention includes an input light coupling structure, a first filtering structure, a light beam splitting tree structure, a filtering structure array, a fluorescence excitation structure array and a light coupling-out structure array arranged in sequence, providing an integrated fluorescence excitation scheme for the detection of fluorescence signals of biological samples. Compared with the traditional excitation scheme, the present invention introduces an on-chip filter, which can reduce the wide-spectrum background light composed of spontaneous radiation fluorescence of lasers or waveguides, thereby reducing shot noise and being more conducive to improving the signal-to-noise ratio and signal-to-background ratio. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0132] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An integrated platform for exciting molecular fluorescence signals, characterized in that: include: An input optical coupling structure is used to couple the laser light emitted by an off-chip laser into the chip; A first filtering structure, wherein the input end of the first filtering structure is connected to the output end of the input light coupling structure, and is used to allow incident laser light of a certain wavelength to pass through and block the background fluorescence of the laser's spontaneous radiation; An optical beam splitting tree structure, wherein an input end of the optical beam splitting tree structure is connected to an output end of the first filtering structure, and is used to split one input light into multiple output lights and form multiple output ends; A filter structure array, comprising a plurality of second filter structures, wherein the input ends of the plurality of second filter structures are connected one-to-one with the plurality of output ends of the light beam splitting tree structure, and are used to allow incident laser light of a certain wavelength to pass through and block the spontaneous radiation background fluorescence of the waveguide material; A fluorescence excitation structure array, comprising a plurality of fluorescence excitation structures, wherein input ends of the plurality of fluorescence excitation structures are connected one-to-one with output ends of the plurality of second filtering structures, and are used to confine the physical space of the fluorescent molecules and excite the fluorescent molecules to generate fluorescent radiation; The light outcoupling structure array comprises a plurality of light outcoupling structures, wherein the input ends of the plurality of light outcoupling structures are connected one-to-one with the output ends of the plurality of fluorescence excitation structures, and are used for coupling out the remaining excitation light after passing through the fluorescence excitation structure array.

2. The integrated platform for exciting molecular fluorescence signals according to claim 1, characterized in that: The input light coupling structure includes a waveguide grating coupler or an edge coupler, and the 3dB line width of the input light coupling structure is greater than 10nm.

3. The integrated platform for exciting molecular fluorescence signals according to claim 1, characterized in that: The first filtering structure includes one of a micro-ring filter, a waveguide grating filter and a cascaded directional coupler structure filter, and the second filtering structure includes a waveguide grating filter or a cascaded directional coupler structure.

4. The integrated platform for exciting molecular fluorescence signals according to claim 3, characterized in that: The waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a straight waveguide and a groove array. The groove array includes a plurality of rectangular grooves arranged in sequence and at equal intervals along the length direction of the straight waveguide, the length direction of the rectangular groove is perpendicular to the length direction of the straight waveguide and the length of the rectangular groove is equal to the width of the straight waveguide, the rectangular groove opens from the upper surface of the straight waveguide and the depth of the rectangular groove is less than the thickness of the straight waveguide, and the rectangular groove is filled with a dielectric material, and the refractive index of the dielectric material is different from the refractive index of the straight waveguide.

5. The integrated platform for exciting molecular fluorescence signals according to claim 3, characterized in that: The waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a straight waveguide and a groove array. The groove array includes a plurality of groove groups arranged in sequence and at equal intervals along the length direction of the straight waveguide. The groove group includes a first groove and a second groove spaced apart in the width direction of the straight waveguide. The first groove and the second groove are both opened from the upper surface of the straight waveguide and the depths of the first groove and the second groove are both less than the thickness of the straight waveguide. The opposite ends of the first groove and the second groove respectively penetrate the side surfaces of the straight waveguide. The first groove and the second groove are both filled with dielectric material, and the refractive index of the dielectric material is different from that of the straight waveguide.

6. The integrated platform for exciting molecular fluorescence signals according to claim 3, characterized in that: The waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a straight waveguide and an island structure array. The island structure array includes a plurality of island structure groups arranged in sequence and at equal intervals along the length direction of the straight waveguide. The island structure group includes a first island structure and a second island structure arranged at intervals in the width direction of the straight waveguide. The first island structure and the second island structure are distributed on opposite sides of the straight waveguide and are symmetrically arranged about the straight waveguide axis. The thickness of the first island structure and the second island structure are both equal to the thickness of the straight waveguide.

7. The integrated platform for exciting molecular fluorescence signals according to claim 3, characterized in that: The waveguide grating filter adopts a waveguide distributed Bragg reflector, which includes a waveguide body and a wing array. The waveguide body includes a first straight waveguide, a second straight waveguide and a third straight waveguide connected in sequence along a specified direction. The widths of the first straight waveguide and the third straight waveguide are the same and greater than the width of the second straight waveguide. The wing array includes a first wing and a second wing arranged along the width direction of the second straight waveguide. The first wing and the second wing are connected to opposite sides of the second straight waveguide and are symmetrically arranged about the axis of the second straight waveguide. The thicknesses of the first wing and the second wing are both equal to the thickness of the second straight waveguide.

8. The integrated platform for exciting molecular fluorescence signals according to claim 1, characterized in that: The working light source wavelength band of the first filtering structure is in the range of 400nm to 800nm, and the working light source wavelength band of the second filtering structure is in the range of 400nm to 800nm.

9. The integrated platform for exciting molecular fluorescence signals according to claim 1, characterized in that: The light splitting tree structure splits one path of input light into multiple paths of output light according to the same splitting ratio.

10. The integrated platform for exciting molecular fluorescence signals according to claim 1, characterized in that: The optical beam splitting tree structure includes one or more optical beam splitter units, and the optical beam splitter unit includes one or more of a Y-branch structure, a 2×2 directional coupler, a 1×2 multimode interference coupler, a 2×2 multimode interference coupler, a 1×3 multimode interference coupler and a 1×5 multimode interference coupler.

11. The integrated platform for exciting molecular fluorescence signals according to claim 1, characterized in that: The fluorescence excitation structure includes a cladding and a waveguide structure coated in the cladding. The surface of the cladding above the waveguide structure is provided with sample wells arranged at a certain period along the waveguide propagation direction. The sample wells are used to load molecular substances that can excite fluorescence. The distance between the bottom surface of the sample well and the top surface of the waveguide structure is less than the evanescent wave penetration distance of the waveguide structure.

12. The integrated platform for exciting molecular fluorescence signals according to claim 11, characterized in that: The waveguide structure adopts a straight waveguide, and the sample well is located directly above the straight waveguide; or the waveguide structure includes a straight waveguide and a plurality of grating structures located on one side of the straight waveguide and connected to the straight waveguide, and the sample well is located directly above the grating structure; or the waveguide structure includes a straight waveguide and a V-shaped metal grating structure located on the straight waveguide, and the sample well is located directly above the V-shaped metal grating structure.

13. The integrated platform for exciting molecular fluorescence signals according to claim 1, characterized in that: The optical outcoupling structure adopts a grating coupler, and the 3dB line width of the optical outcoupling structure is greater than 10nm.

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