Fluorescence spectrometer based on antisymmetric array waveguide structure, sensing chip and system

Abstract

The invention relates to a fluorescence spectrometer based on an antisymmetric array waveguide structure, a sensing chip and a system. The fluorescence spectrometer comprises: an input part for inputting a fluorescence signal; the transmission part comprises a waveguide array which is connected with the input part and is composed of a plurality of transmission waveguides, the lengths of the transmission waveguides are sequentially increased or decreased according to a fixed value in the arrangement direction of the transmission waveguides, and the fluorescence signals are decomposed into a plurality of beam splitting signals with the same optical path difference; and the output part is used for enabling the plurality of beam splitting signals with the same optical path difference to form interference at different positions and outputting spectral signals. According to the invention, the chip-level fluorescence spectrum sensor with low cost and high integration level can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of on-chip fluorescence sensing, and particularly to a fluorescence spectrometer, a sensing chip and a system based on an anti-symmetric array waveguide structure. Background Art

[0002] A fluorescence sensor detects the target molecule through specific chemical reactions or physical adsorption and desorption interactions between a fluorescence-sensitive material and the molecule to be detected, so that the intensity and wavelength characteristics of the fluorescence before and after the interaction change, thereby achieving the detection purpose. Due to its advantages of high sensitivity, high specificity and rapid response, it has been widely used in related fields such as public safety, environmental monitoring and control of hazardous chemicals.

[0003] Wavelength division multiplexing technology plays a very important role in the fields of optical communication and integrated optics. The arrayed waveguide grating structure is the most basic and common structural device to achieve this function. It not only has good stability and high spectral resolution, but also can ensure performance while meeting the mainstream processing technology. Its wavelength separation function is also often used in the construction of on-chip spectrometers, and related applications have been reported in the biomedical field. A key parameter of the arrayed waveguide grating is the optical path difference between waveguides, which is proportional to the central wavelength and inversely proportional to the free spectral range. In the communication field, the central wavelength is in the micrometer band, and the free spectral range is usually several to more than ten nanometers, so the optical path difference is usually in the micrometer order of magnitude. However, the central wavelength of the fluorescent material is in the shorter visible light band, and the bandwidth is usually in the order of hundreds of nanometers, so the optical path difference needs to reach the nanometer order of magnitude. Therefore, it is impossible to use the conventional symmetric arrayed waveguide grating structure in the communication field to achieve.

[0004] Existing fluorescence material-based sensors usually detect the change in fluorescence intensity to analyze the target gas. Therefore, only a simple photodetector is needed to convert the light intensity information into an electrical signal. If detection is to be achieved through the spectral change of fluorescence, complex spatial optical paths are required for spectral separation or a relatively large spectral detection device is needed to obtain the spectrum, which makes it difficult to miniaturize and reduce the cost of the sensor. Therefore, it is particularly important to develop a low-cost and highly integrated chip-level fluorescence spectrometer sensor. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a fluorescence spectrometer, a sensing chip and a system based on an anti-symmetric array waveguide structure, which can realize a low-cost and highly integrated chip-level fluorescence spectrometer sensor.

[0006] The technical solution adopted by the present invention to solve its technical problems is: to provide a fluorescence spectrometer based on an anti-symmetric array waveguide structure, including:

[0007] An input part for inputting a fluorescence signal;

[0008] A transmission part, including a waveguide array composed of multiple transmission waveguides connected to the input part, where the lengths of the transmission waveguides increase or decrease sequentially by a fixed value along their arrangement direction, decomposing the fluorescence signal into multiple split beam signals with the same optical path difference;

[0009] An output part, configured to cause the multiple split beam signals with the same optical path difference to interfere at different positions and output a spectral signal.

[0010] Further, the transmission waveguide includes a first bent waveguide bent towards one side, a second bent waveguide bent towards the other side, and an equal difference waveguide for connecting the first bent waveguide and the second bent waveguide. One of the first bent waveguide and the second bent waveguide is longer and the other is shorter, and the lengths of the bent waveguides of each transmission waveguide are equal. The length of the bent waveguide is the sum of the lengths of the first bent waveguide and the second bent waveguide of the same transmission waveguide.

[0011] Further, the equal difference waveguide increases or decreases sequentially by a fixed value along its arrangement direction.

[0012] Further, the input part includes an input waveguide and an input planar waveguide. The input end of the input planar waveguide is connected to the output end of the input waveguide, and the output end of the input planar waveguide is connected to the input ends of the respective transmission waveguides. The width of the input planar waveguide gradually increases from its input end to its output end.

[0013] Further, the output part includes an output planar waveguide and an output waveguide. The input end of the output planar waveguide is connected to the output ends of the respective transmission waveguides. After the fluorescence signals output by the array of transmission waveguides interfere at different positions at the output end of the output planar waveguide, the generated spectral signals enter the corresponding output waveguide and are output.

[0014] The present invention also provides a fluorescence spectral sensing chip, including:

[0015] A substrate;

[0016] An optical waveguide structure disposed on the substrate, including a light source coupling-in structure, a fluorescence sensing structure, any of the above-mentioned fluorescence spectrometers, and an edge coupling-out structure connected in sequence. A fluorescence material layer is coated on the fluorescence sensing structure, and the fluorescence material layer is excited by a light beam input by the light source coupling-in structure to generate a fluorescence signal. After the fluorescence spectrometer detects the spectral signal of the generated fluorescence signal, it is output through the edge coupling-out structure;

[0017] A window protection structure covers the optical waveguide structure and forms a sample channel between the window protection structure and the optical waveguide structure, allowing the substance to be measured to flow into the sample channel through the sample channel and react with the fluorescent material layer, thereby causing a change in the spectral signal.

[0018] Further, the window protection structure includes a window protection layer and a sample channel layer. The window protection layer includes a first protection layer covering the light source coupling-in structure and a second protection layer covering the fluorescence spectrometer and the edge coupling-out structure. The sample channel layer includes an inflow channel layer disposed on the first protection layer, an outflow channel layer disposed on the second protection layer, and a sensing channel layer disposed between the inflow channel layer and the outflow channel layer. An inflow region of the sample channel is formed between the first protection layer, the inflow channel layer, and the sensing channel layer. A reaction region of the sample channel is formed between the sensing channel layer and the fluorescent material layer. An outflow region of the sample channel is formed between the second protection layer, the outflow channel layer, and the sensing channel layer.

[0019] Further, it further includes a photosensitive element for converting the spectral signal output by the edge coupling-out structure into an electrical signal.

[0020] The present invention also provides a fluorescence spectroscopy sensing system, including:

[0021] A light source for generating an excitation beam;

[0022] A flow rate module for adjusting the flow rate and velocity of the substance to be measured;

[0023] Any one of the sensing chips as described above is respectively connected to the light source and the flow rate module for detecting and generating the fluorescence spectrum of the substance to be measured by using the excitation beam.

[0024] Beneficial effects

[0025] Due to the adoption of the above technical solution, compared with the prior art, the present invention has the following advantages and positive effects: By generating, conducting, and spectrally separating fluorescence signals within the optical waveguide, the present invention reduces the loss of fluorescence during spatial transmission, avoids the loss during the coupling process between the fluorescence signal and the spectrometer, and improves the detection sensitivity; The present invention introduces an anti-symmetric structure into the spectrometer design, such that the shortest waveguide on the left side is exactly connected to the longest waveguide on the right side. Therefore, the optical path difference of the arrayed waveguides is only composed of the equally spaced waveguides with equal differences in the middle, and is not limited by parameters such as the bending radius, the size of the input planar waveguide, and the number of transmission channels. Thus, an infinitesimal optical path difference can be achieved theoretically. Meanwhile, while achieving a large bandwidth and sufficient resolution, it ensures that the structure occupies a sufficiently small area, which lays a foundation for the development of large-scale array devices; The present invention uses the real-time change of the fluorescence spectrum signal to detect gases, can effectively distinguish the signal jitter caused by the light source and interfering gases, and greatly improves the specific recognition ability of the device; The present invention adopts a single-layer optical waveguide structure to achieve the real-time separation of fluorescence spectrum signals. Compared with modulation-type and computational spectrometers, this design has an extremely simple process flow and has the advantages of scale and low cost; The chip structure of the present invention can be compatible with gas-phase and liquid-phase detections, has strong versatility for various fluorescent materials, and can be widely applied to the fields of chemical and biological fluorescence sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the first embodiment of the present invention;

[0027] Figure 2 is a schematic cross-sectional view of the chip structure of the second embodiment of the present invention;

[0028] Figure 3 is a schematic diagram of the working principle of the second embodiment of the present invention;

[0029] Figure 4 is a schematic diagram showing the functional relationship between the fluorescence intensity of each output channel and time in the second embodiment of the present invention;

[0030] Figure 5 is a functional relationship diagram showing the change of the fluorescence spectrum of the fluorescent material before and after sensing in the second embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0032] The first embodiment of the present invention relates to a fluorescence spectrometer based on an anti-symmetric array waveguide structure, which can realize real-time separation of ultra-wideband fluorescence spectra on a chip. The fluorescence spectrometer specifically includes:

[0033] An input part for inputting a fluorescence signal;

[0034] A transmission part including a waveguide array composed of multiple transmission waveguides connected to the input part. The lengths of the respective transmission waveguides increase or decrease in sequence by a fixed value along their arrangement direction, and the input fluorescence signal is decomposed into multiple split signals with the same optical path difference;

[0035] An output part for causing the above-mentioned multiple split signals with the same optical path difference to form interference at different positions and outputting a spectral signal.

[0036] As Figure 1 shown, in some embodiments, each transmission waveguide 1001 is composed of a forward waveguide 107 (first bent waveguide), an equal-difference waveguide 108, and a reverse waveguide 109 (second bent waveguide), and there is an anti-symmetric relationship between the forward waveguide 107 and the reverse waveguide 109.

[0037] More specifically, the two ends of any one transmission waveguide 1001 are respectively a longer forward waveguide 107 and a corresponding shorter reverse waveguide 109, or respectively a shorter forward waveguide 107 and a corresponding longer reverse waveguide 109, and are connected by a corresponding equal-difference waveguide 108 in the middle. Assuming that the sum of the lengths of the forward waveguide 107 and the reverse waveguide 109 of the same transmission waveguide 1001 is the length of the bent waveguide, the lengths of the bent waveguides of the respective transmission waveguides 1001 in the array are equal, and the lengths of the equal-difference waveguides 108 of the respective transmission waveguides 1001 satisfy an arithmetic progression relationship. This makes the length difference of each transmission waveguide 1001 in the array only determined by the equal-difference waveguide 108 connected in the middle, and finally forms an array transmission waveguide 1002 composed of multiple transmission waveguides with a fixed length difference. In some preferred embodiments, the equal-difference waveguides 108 in the array are arranged in concentric circles.

[0038] In the existing symmetric AWG, the right part of the transmission waveguide is obtained by mirror symmetry with the left part, that is, the shortest waveguide on the left is connected to the shortest waveguide on the right, and the longest waveguide is connected to the longest waveguide, and the total length forms an arithmetic progression. The anti-symmetric AWG transmission waveguide is obtained by first horizontally flipping and then vertically flipping the left part, which is equivalent to rotating by about 180°. This makes the shortest waveguide on the left part just connected to the longest waveguide on the right part, ensuring that the total length of the bent waveguide part is equal, so that the optical path difference is only composed of the arithmetic waveguides with arithmetic progression changes in the middle connection part, and thus an infinitesimal optical path difference can be achieved theoretically. The optical path difference of the symmetric type is composed of the transmission waveguide and is limited by parameters such as the bending radius, the size of the input planar waveguide, and the number of transmission channels, and a very small optical path difference cannot be achieved. According to the theoretical formula, the optical path difference is proportional to the central wavelength and inversely proportional to the FSR free spectral range. For the spectrum of the fluorescent material, it has a large bandwidth of dozens to hundreds of nanometers and a central wavelength shorter than that of the communication band. Therefore, compared with the AWG used in the communication field, it has an extremely small optical path difference, so a symmetric design cannot be adopted.

[0039] In addition, the input part of the fluorescence spectrometer can be composed of an input waveguide 105 and an input planar waveguide 106, and the output part can be composed of an output planar waveguide 110 and an output waveguide 111. The fluorescence signal enters through the input waveguide 105, gradually disperses in the input planar waveguide 106 and enters the array transmission waveguide 1002. After being conducted by the array transmission waveguide 1002, an optical path difference is formed. Fluorescence signals of different wavelengths form superposition interference at different positions after passing through the output planar waveguide 110 and enter the corresponding output waveguide 111.

[0040] The second embodiment of the present invention relates to a fluorescence spectrum sensing chip, including:

[0041] A substrate;

[0042] An optical waveguide structure disposed on the substrate, including a light source coupling-in structure, a fluorescence sensing structure, a fluorescence spectrometer, and an edge coupling-out structure connected in sequence. A fluorescent material layer is coated on the fluorescence sensing structure, and the fluorescent material layer is excited by the light beam input by the light source coupling-in structure to generate a fluorescence signal. After the fluorescence spectrometer detects the spectral signal of the generated fluorescence signal, it is output through the edge coupling-out structure;

[0043] A window protection structure covering the optical waveguide structure and forming a sample channel between the optical waveguide structure, so that the substance to be measured flows in through the sample channel and reacts with the fluorescent material layer, thereby causing a change in the spectral signal.

[0044] Among them, the fluorescence spectrometer involved in this embodiment can adopt any one of the above fluorescence spectrometers.

[0045] The following further describes this embodiment in conjunction with the accompanying drawings.

[0046] As Figure 2 and Figure 3 shown, the chip involved in this embodiment includes a silicon-based optical waveguide 100, a sample channel 200, and a photosensitive element 300.

[0047] Among them, the silicon-based optical waveguide 100 includes a waveguide structure layer 203, a window protection layer 204, and a fluorescent material layer 205 disposed on the waveguide structure layer 203. The optical waveguide structure layer 203 includes a light source coupling structure 102, a fluorescence sensing structure 103, a fluorescence spectrometer 104, and an edge coupling structure 112. The window protection layer 204 includes a window area 207 and a protection area 208. The window area 207 is disposed above the fluorescence sensing structure 103, and the fluorescent material layer 205 is coated or injected into the sensing window area 207. The sample channel 200 sequentially includes an inflow channel 2001, a reaction channel 2002, and an outflow channel 2003. The reaction channel 2002 is disposed above the window area 207, constituting a sensing area for the fluorescent material and the substance to be measured.

[0048] The photosensitive element 300 is composed of a filter 302 and a photodetector 301 capable of converting an optical signal into an electrical signal, and is disposed behind the edge coupling structure 112 and perpendicular to the silicon-based optical waveguide 100. The filter 302 is placed between the photodetector 301 and the silicon-based optical waveguide 100. The filter 302 should be a long-pass filter, and the wavelength is greater than the wavelength of the light source. The photodetector 301 can convert the multi-channel optical signal of the edge coupling structure 112 into an electrical signal.

[0049] External laser enters the waveguide structure layer 203 through the light source coupling structure 102. When the laser passes through the sensing area, it will excite the fluorescent material layer 205 to generate a fluorescent signal. The fluorescent signal is coupled back to the fluorescence sensing structure 103 and transmitted to the fluorescence spectrometer 104, and then separated into multiple spectral signals and exported to the photosensitive element 300 through the edge coupling structure 112. At the same time, the substance to be detected enters the sensing area through the sample channel 200, and after reacting with the fluorescent material, it can change the spectral signal, and then relevant detections are carried out by analyzing the real-time change of the fluorescence spectral signal, such as Figure 4 and Figure 5 shown.

[0050] The third embodiment of the present invention relates to a fluorescence spectral sensing system, which includes a fluorescence spectral sensing chip, a laser light source, and a flow module. Among them, the fluorescence spectral sensing chip can adopt any one of the above fluorescence spectral sensing chips. The laser light source is used to generate laser and introduce it into the silicon-based optical waveguide, and the flow module is used to connect the channel of the substance to be measured and adjust the flow rate and velocity.

[0051] In some preferred embodiments, the fluorescence spectroscopy sensing system may further include a touch display module for displaying the real-time spectrum information and the detected substance information and implementing touch control of the various functions of the system. A control circuit may also be selected to automatically control the operation of the laser light source, the flow module, and the touch display module, receive the electrical signals of the photosensitive element, analyze and process them to obtain real-time spectrum information, and then obtain the information of the substance to be measured based on the change of the electrical signals and transmit it to the touch display module for display.

Claims

1. A fluorescence spectrometer based on an antisymmetric array waveguide structure, characterized in that: include: An input part, used for inputting fluorescence signals; A transmission part, comprising a waveguide array composed of a plurality of transmission waveguides connected to the input part, wherein the length of the transmission waveguides increases or decreases in sequence according to a fixed value along the arrangement direction thereof, so as to decompose the fluorescence signal into a plurality of split beam signals having the same optical path difference; The output part is used to make the multiple beam splitting signals with the same optical path difference form interference at different positions and output a spectrum signal.

2. The fluorescence spectrometer according to claim 1, characterized in that: The transmission waveguide includes a first curved waveguide curved toward one side, a second curved waveguide curved toward the other side, and an arithmetic difference waveguide used to connect the first curved waveguide and the second curved waveguide, one of the first curved waveguide and the second curved waveguide is longer and the other is shorter, and the curved waveguide lengths of each of the transmission waveguides are equal, and the curved waveguide length is the sum of the lengths of the first curved waveguide and the second curved waveguide of the same transmission waveguide.

3. The fluorescence spectrometer according to claim 2, characterized in that: The arithmetic difference waveguides increase or decrease in sequence according to a fixed value along their arrangement direction.

4. The fluorescence spectrometer according to claim 1, characterized in that: The input part includes an input waveguide and an input slab waveguide, the input end of the input slab waveguide is connected to the output end of the input waveguide, the output end of the input slab waveguide is connected to the input end of each of the transmission waveguides, and the width of the input slab waveguide gradually increases from its input end to its output end.

5. The fluorescence spectrometer according to claim 1, characterized in that: The output part includes an output slab waveguide and an output waveguide. The input end of the output slab waveguide is connected to the output end of each of the transmission waveguides, so that after the fluorescence signal output by the array transmission waveguide forms interference at different positions of the output end of the output slab waveguide, the generated spectral signal enters the corresponding output waveguide and is output.

6. A fluorescence spectrum sensor chip, characterized in that: include: substrate; An optical waveguide structure, disposed on the substrate, comprising a light source coupling structure, a fluorescence sensing structure, any fluorescence spectrometer as described in claims 1 to 5, and an edge coupling structure connected in sequence, wherein the fluorescence sensing structure is coated with a fluorescent material layer, the fluorescent material layer is excited by the light beam input by the light source coupling structure to generate a fluorescence signal, and the fluorescence spectrometer detects a spectral signal of the generated fluorescence signal and outputs the spectral signal through the edge coupling structure; The window protection structure covers the optical waveguide structure and forms a sample channel with the optical waveguide structure, so that the substance to be tested flows into the sample channel and reacts with the fluorescent material layer, thereby causing the change of the spectral signal.

7. The sensor chip according to claim 6, characterized in that: The window protection structure includes a window protection layer and a sample channel layer, the window protection layer includes a first protection layer covering the light source coupling-in structure, and a second protection layer covering the fluorescence spectrometer and the edge coupling-out structure, the sample channel layer includes an inflow channel layer placed on the first protection layer, an outflow channel layer placed on the second protection layer, and a sensing channel layer placed between the inflow channel layer and the outflow channel layer; an inflow area of ​​the sample channel is formed between the first protection layer, the inflow channel layer and the sensing channel layer, a reaction area of ​​the sample channel is formed between the sensing channel layer and the fluorescent material layer, and an outflow area of ​​the sample channel is formed between the second protection layer, the outflow channel layer and the sensing channel layer.

8. The sensor chip according to claim 6, characterized in that: It also includes a photosensitive element, which is used to convert the spectral signal output by the edge coupling structure into an electrical signal.

9. A fluorescence spectrum sensing system, characterized in that: include: a light source for generating an excitation light beam; A flow module, used to adjust the flow rate and flow velocity of the substance to be tested; Any sensor chip as described in claims 6-8, connected to the light source and the flow module respectively, and used to generate a fluorescence spectrum of the substance to be tested by detecting the excitation light beam.

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