A microring sensor integrated with a high-order flattened filter

Abstract

The present invention discloses a micro-ring sensor integrated with a high-order flat-topped filter, which includes a light source LED array, a cascaded dual-ring sensing array chip integrated with a high-order flat-topped filter, a detector array, a fan-out packaging wafer, a microfluidic channel device, and a voltage power supply. The light source LED array is integrated with the sensing array chip in a flip-chip manner to couple light into the chip. After being filtered by the flat-topped filter, biomolecular information is obtained on the sensing rings of the cascaded dual-ring sensor, and the detector array receives the light intensity signal to achieve sensing detection. By integrating the high-order flat-topped filter, the sensitivity of the cascaded dual-ring biosensing based on intensity detection is improved; by using epoxy resin material to prepare the fan-out packaging wafer, the size of the silicon wafer is reduced and the cost is saved; the present invention realizes the integration of active and passive components, which is beneficial to the further integrated development of the biosensing system.

Description

Technical Field

[0001] The invention relates to a sensing detection instrument, in particular to a micro-ring sensor integrated with a high-order flat-top filter. Background Art

[0002] Detection instruments based on photon integrated chips have the advantages of high sensitivity, high selectivity, high integration, and small sample size, and have great potential in biosensing detection. Traditional cascaded dual-ring sensors can greatly improve the sensitivity of sensors by using the vernier effect. They usually have two working modes: wavelength detection and intensity detection. Detecting biological information based on wavelength changes requires expensive and complex equipment to obtain spectral information, such as using tunable lasers and power meters, or broadband light sources and spectrometers. Intensity-based sensing detection only requires low-cost broadband light sources and optical power meters to achieve sensing. The spectral width of commercial broadband light sources is 20-40nm. Due to the large spectral width, the sensitivity of intensity sensing is seriously reduced, so the light source needs to be filtered. Using a spatial filter to filter the broadband light source and then coupling it into the sensor will increase the size and cost of the sensor system, which is not conducive to the development of integration. Therefore, it is necessary to integrate a filter with a suitable spectral width on the cascaded dual-ring sensor chip to improve the sensitivity of intensity detection and reduce the sensitivity of ambient temperature.

[0003] At present, the research on silicon photonic integrated chip sensing mainly uses optical fiber arrays to input and receive light, so it is necessary to reserve tens to hundreds of mm 2 The silicon chip size is reduced to ensure that the microfluidic channel and optical input and output can be integrated on the chip. That is, the sensing area has a very small duty cycle, and most of the chip area is only used for mechanical support of the microfluidic channel and fixation of the optical fiber array. This not only makes the compactness advantage of silicon photonic integration lose, but also increases the cost of the chip, while limiting the further integrated development of microfluidic biosensors. Most biosensor chips are disposable to ensure no pollution, so there is an urgent need to reduce the cost of chips as sensor consumables. Summary of the invention

[0004] The object of the present invention is to provide a micro-ring sensor with an integrated high-order flat-top filter to overcome the deficiencies in the prior art.

[0005] The object of the present invention is achieved through the following technical solutions: a micro-ring sensor with integrated high-order flat-top filter, the sensor comprising a fan-out package wafer, and integrating a light source LED array, a cascaded dual-ring sensor array chip, a detector array, a microfluidic channel device and a voltage power supply on the fan-out package wafer;

[0006] The cascaded dual-ring sensing array chip consists of multiple cascaded dual-ring sensing structures arranged in an array; the cascaded dual-ring sensing structure includes an input grating coupler, a high-order series filter, a cascaded dual-ring sensor, a drop-port output grating coupler, and a pass-port output grating coupler; light is coupled into the input grating coupler by a light source LED array, filtered by the high-order series filter, and sensing detection is realized in the cascaded dual-ring sensor part. Finally, the detection signal is output through the drop-port output grating coupler and the pass-port output grating coupler, and the signal is received by a detector array; the cascaded dual-ring sensor includes a sensing ring and a reference ring, and a biomolecular film is modified on the sensing ring.

[0007] The described microfluidic channel device is aligned with the sensing ring, so that the liquid to be measured in the microfluidic channel flows through the sensing ring in each array; the voltage power supply applies a voltage to the cascaded dual-ring sensing array chip integrated with a thermal electrode pair to the high-order flat-topped filter to achieve thermal tuning.

[0008] Further, the microfluidic channel device includes a liquid inlet end, an outlet end, and a microfluidic channel passing above the sensing ring.

[0009] Further, in the multiple cascaded dual-ring sensing structures, different biomolecular films are respectively modified on the sensing rings of each path, and a single microfluidic channel device can directly detect multiple biomolecular components on the sensing array chip.

[0010] Further, the high-order series filter is formed by cascading n rings with different radii to achieve a channel rejection ratio greater than 30 dB and a free spectral range greater than or equal to 40, obtaining an n-order series filter; in the n-order series filter, FSR 总 is the least common multiple of FSR i , where i = 1, 2, 3,..., n; FSR i is the free spectral range corresponding to each resonant ring; the values of n FSR i satisfy FSR 总 ≥40;

[0011] According to and determine the radius R i of each resonant ring and the resonant order m i ; to reduce loss, the ring radius needs to satisfy R ≥ 5, that is, m ≥ 37.

[0012] Further, in order to flatten the channel spectrum of the high-order series filter, the coupling coefficients k1 between the ring and the input / output waveguides, the coupling coefficient k2 between the rings, and the propagation constant k p of the ring satisfy where n is the number of cascaded rings; the high-order cascaded filter replaces the traditional input and output waveguides with a Mach-Zehnder structure, and at the same time, a thermal electrode is added to the outer wall of the Mach-Zehnder structure to adjust the deviation of the coupling coefficient caused by process errors; among them, the coupling coefficient k of the Mach-Zehnder part MZ has the relationship with the original k1 as

[0013] Furthermore, a thermal electrode is fabricated on the high-order cascaded filter to finely adjust its effective refractive index, which is used to compensate for the passband top ripple phenomenon caused by the coupling-induced frequency shift effect.

[0014] Furthermore, the fan-out package wafer is fabricated using an epoxy resin material and becomes an extended part of the silicon wafer; electrodes are fabricated on the fan-out package wafer to achieve electrical packaging and complete the alignment packaging of the microfluidic channel device.

[0015] Furthermore, the light source LED array and the detector array are fixed on the cascaded dual-ring sensing array chip integrated with the high-order flattened filter in a flip-chip manner; the light source LED array is aligned with the input grating coupler array, and the detector array is aligned with the drop-end output grating coupler array and the pass-end grating coupler array.

[0016] Furthermore, the 3dB bandwidth of the high-order cascaded filter is related not only to the radius of each ring but also to the coupling coefficient; when the radii of the four cascaded rings are determined, the 3dB bandwidth of the filter is finely adjusted by adjusting the coupling ratio of the coupling region.

[0017] The beneficial effects of the present invention are as follows:

[0018] The present invention uses an on-chip integrated flattened filter for filtering the intensity detection of the cascaded dual-ring sensor. The flattened filter has the advantages of high extinction ratio, large FSR, and flattened passband. Compared with directly using a broadband light source input for intensity detection, the structure of the integrated flattened filter has higher sensitivity.

[0019] The present invention uses an on-chip integrated flattened filter for filtering the intensity detection of the cascaded dual-ring sensor. Due to the addition of a thermal electrode, its bandwidth, central wavelength, and coupling coefficient can all be adjusted, which can not only compensate for the deviation of the coupling coefficient caused by process effects but also reduce the ripple effect caused by coupling-induced frequency shift (CIFS).

[0020] The present invention uses an on-chip integrated flattened filter for filtering the intensity detection of the cascaded dual-ring sensor. Compared with a Gaussian-type spatial filter, it has the advantage of temperature insensitivity, and at the same time reduces the overall volume of the system, which is beneficial to the development of the sensor towards integration and miniaturization.

[0021] In the present invention, the light source LED array and the detector array are aligned and fixed on the sensing chip in a flip-chip manner, realizing the coupled input of the light source and the detection and reception of the optical signal, saving the space for spatial light or fiber light, achieving the integration of active and passive components, and facilitating the further integrated application of the biochip.

[0022] The present invention uses epoxy resin material to prepare a fan-out packaged wafer, which reduces the size of the silicon wafer and saves costs. At the same time, space is reserved for microfluidics and electrical packaging, etc., to achieve a more compact and economical reading, which is beneficial to the research and development of multiplexed and low-cost point-of-care diagnostic devices. Brief Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the overall structure of the micro-ring sensor integrating a high-order flattened filter according to the present invention;

[0024] Figure 2 It is a schematic diagram of the cascaded dual-ring sensing structure according to the present invention;

[0025] Figure 3 It is a schematic diagram of the structure of the fourth-order series flattened filter according to the present invention;

[0026] Figure 4 It is the passband response curve of the fourth-order series flattened filter according to the present invention;

[0027] Figure 5 It is the schematic diagram of the intensity detection principle of the cascaded dual-ring;

[0028] Figure 6 It is the simulation diagram of the intensity detection sensitivity corresponding to different filtering widths;

[0029] Figure 7 It is the simulation diagram of the stability of temperature drift when using a Gaussian filter and the fourth-order series flattened filter according to the present invention respectively. Detailed Description of the Preferred Embodiments

[0030] The following further describes the specific embodiments of the present invention in detail with reference to the accompanying drawings.

[0031] A micro-ring sensor integrating a high-order flattened filter, the sensor includes a fan-out packaged wafer, and integrates a light source LED array, a cascaded dual-ring sensing array chip, a detector array, a microfluidic channel device and a voltage power supply on the fan-out packaged wafer;

[0032] The fan-out packaged wafer is prepared using epoxy resin material and becomes an extended part of the silicon wafer; electrodes are prepared on the fan-out packaged wafer to achieve electrical packaging and complete the alignment packaging of the microfluidic channel device.

[0033] The cascaded dual-ring sensing array chip consists of an array of multiple cascaded dual-ring sensing structures; the cascaded dual-ring sensing structure includes an input grating coupler, a high-order series filter, a cascaded dual-ring sensor, a drop-port output grating coupler, and a pass-port output grating coupler; light is coupled into the input grating coupler by a light source LED array, filtered by the high-order series filter, realizes sensing detection in the cascaded dual-ring sensor part, and finally outputs the detection signal through the drop-port output grating coupler and the pass-port output grating coupler, and the signal is received by a detector array; the cascaded dual-ring sensor includes a sensing ring and a reference ring, and a biomolecular film is modified on the sensing ring.

[0034] In the multiple cascaded dual-ring sensing structures, different biomolecular films are respectively modified on the sensing rings of each path, and a single microfluidic channel device can directly detect multiple biomolecular components on the sensing array chip.

[0035] The described high-order series filter is composed of n rings with unequal radii in series to achieve a channel rejection ratio greater than 30 dB and a free spectral range greater than or equal to 40 nm, obtaining an n-order series filter; in the n-order series filter, FSR 总 is the least common multiple of FSR i , where i = 1, 2, 3,..., n; FSR i is the free spectral range corresponding to each resonant ring; the values of n FSR i satisfy FSR 总 ≥40 nm;

[0036] According to and , the radius R i of each resonant ring and the resonance order m i are determined; to reduce losses, the ring radius needs to satisfy R≥5 μm, that is, m≥37.

[0037] In order to flatten the channel spectrum lines of the high-order series filter, the coupling coefficients k1 between the rings and the input / output waveguides, the coupling coefficient k2 between the rings, and the propagation constant k p of the rings satisfy where n is the number of series-connected rings; the high-order series filter replaces the traditional input / output waveguides with a Mach-Zehnder structure, and at the same time, a thermal electrode is added to the outer wall of the Herzen structure to adjust the deviation of the coupling coefficient caused by process errors; among them, the coupling coefficient k MZ of the Mach-Zehnder part and the original k1 have the relationship

[0038] A thermal electrode is prepared on the high-order series filter to finely adjust its effective refractive index, so as to compensate for the passband top ripple phenomenon caused by the coupling-induced frequency shift effect.

[0039] The microfluidic channel device is aligned with the sensing ring, allowing the liquid to be measured in the microfluidic channel to flow through the sensing rings in each array; the voltage power supply applies a voltage to the cascaded dual-ring sensing array chip of the integrated high-order flat-topped filter through the thermal electrode pair to achieve thermal tuning. The microfluidic channel device includes a liquid inlet end, an outlet end, and a microfluidic channel passing above the sensing rings.

[0040] The light source LED array and the detector array are fixed on the cascaded dual-ring sensing array chip of the integrated high-order flat-topped filter by flip-chip; the light source LED array is aligned with the input grating coupler array, and the detector array is aligned with the drop-end output grating coupler array and the pass-end grating coupler array.

[0041] The 3dB bandwidth of the high-order series filter is related not only to the radius of each ring but also to the coupling coefficient; when the radii of the four series rings are determined, the 3dB bandwidth of the filter is finely tuned by adjusting the coupling ratio of the coupling region.

[0042] Example: As Figure 1 shown, an overall structural schematic diagram of a Figure 1 micro-ring sensor with an integrated high-order flat-topped filter provided by the present invention is composed of a light source LED array 1, a cascaded dual-ring sensing array chip 2, a detector array 3, a fan-out packaged wafer 4, a microfluidic channel device 5, and a voltage power supply 6.

[0043] The silicon crystal sensing chip with a waveguide structure is embedded in the epoxy resin material to form the fan-out packaged wafer 4, realizing fan-out wafer-level packaging (FOWLP). The pads of the electrodes are extended to the fan-out part through metal wires for easy electrical packaging. The PDMS microfluidic channel device 5 is aligned and packaged with the reorganized wafer for the inflow and outflow of trace biological samples. The present invention is also applicable to platforms based on various waveguide materials such as silica, SOI, silicon nitride, and silicon oxynitride.

[0044] Figure 2 It is a schematic diagram of a cascaded dual-ring sensing structure based on intensity detection for a single on-chip integrated high-order flat-topped filter, including an input grating coupler 21, a fourth-order series filter 22 (circled with a dashed line), a cascaded dual-ring sensor 23 (including a sensing ring 24 and a reference ring 25), a drop-end output grating coupler 26, a pass-end output grating coupler 27, and a modified biomolecular film 28. By forming an array of 32 cascaded dual-ring sensing structures and modifying 32 probe substances respectively, 32 biomolecular components can be directly detected on the sensing array chip 2.

[0045] The 32-channel cascaded dual-ring sensing structure corresponds to 32 drop-end output grating couplers 26 and 32 through-end output grating couplers 27. The light source LED array 1 and the detector array 3 are encapsulated in a flip-chip manner. The light source LED array 1 is aligned and encapsulated with the input grating coupler 21, and the detector array 3 is aligned and encapsulated with the drop-end output grating coupler 26 and the through-end output grating coupler 27.

[0046] Design an on-chip integrated high-order flattened filter-based cascaded dual-ring sensing structure based on the SOI platform. Use the TM mode as the optical transmission mode of the sensor, and its evanescent wave has a stronger interaction with the biological sample to be measured, which can effectively improve the sensing sensitivity. Table 1 lists the specific design parameters.

[0047] Table 1 Main design parameters of TM mode sensing on the SOI platform

[0048]

[0049] Figure 3 It is a schematic diagram of the structure of a fourth-order cascaded flattened filter. For a high-order cascaded filter, the higher the cascaded order, the steeper the descending edge of its passband, but the ripple effect caused by the coupling-induced frequency shift (CIFS) will also be more obvious. The present invention selects a fourth-order cascaded filter.

[0050] In order to filter a broadband light source, the FSR of the designed flattened filter needs to satisfy FSR≥40nm. For a fourth-order cascaded filter, FSR 总 is the least common multiple of FSR i (i = 1, 2, 3, 4), and FSR i is the free spectral range corresponding to each resonant ring. In the design, take the values of 4 FSR i so that their least common multiple meets the requirement of FSR≥40nm. The free spectral range is The radius of each ring is m i is the resonant order of each resonant ring. Therefore To reduce the transmission loss, the ring radius needs to satisfy R≥5um, that is, m≥37. At the same time, the smaller the radius of each ring, that is, the larger the FSR of each ring, the greater the rejection ratio of the flattened filter.

[0051] Take m i = [80, 70, 60, 50], corresponding to the free spectral range of FSR i = [9.34nm, 10.67nm, 12.45nm, 14.94nm], corresponding to the radius of R i= [10.97um, 9.60um, 8.22um, 6.85um]. The FSR of this design 总 = 38.3nm, which can basically meet the filtering requirements.

[0052] The 3dB bandwidth of the flattened filter is related to the radius of each ring and the coupling coefficient. When the radii of the four series-connected rings are determined, the 3dB bandwidth of the filter can be fine-tuned by adjusting the coupling ratio of the coupling region. For an n-order series filter, in order to obtain a flattened filtering spectrum, the coupling coefficient k1 between the ring and the input / output waveguide and the coupling coefficient k2 between the rings need to satisfy formula (1)

[0053]

[0054] where k p is the propagation constant of the ring, and n is the order of the series filter. To ensure a low insertion loss of the filter, k1 = 0.25 is taken, then k2 = 0.0156. Since the coupling coefficient of the microring resonator is deviated due to process influence, in order to accurately control the coupling coefficient, the coupling part between the ring and the input / output waveguide is changed to a Mach-Zehnder (MZ) structure coupling, then the coupling coefficient k MZ between the Mach-Zehnder part and the original k1 is

[0055]

[0056] then k MZ = 0.75. The passband response curve of this fourth-order series flattened filter is as Figure 4 shown.

[0057] In high-order filters, due to the phase shift in the coupling region, the coupling-induced frequency shift (CIFS) effect occurs, resulting in ripple phenomena at the top of the passband, which can be compensated by pre-distorting the resonant frequencies of each cavity. In this invention, a thermal electrode is added on the basis of the high-order filter, and the equivalent refractive index is heated and fine-tuned to compensate for the resonant frequency shift of CIFS. The addition of the thermal electrode can also control the deviation of the coupling coefficient caused by process errors. In this embodiment, a 3um-wide TiN thermal electrode is added above the ring and the arms of the MZI, and the voltage applied to each thermal electrode can be adjusted respectively to adjust the center wavelength of the filtering, adjust the coupling coefficient, and reduce the ripple effect caused by the coupling-induced frequency shift (CIFS). As Figure 4 shown, the 3dB bandwidth of the fourth-order series flattened filter designed in this invention is 0.7nm. In the cascaded dual-ring sensor 23, the radius of the sensing ring 24 is 150um, and the radius of the reference ring 25 is 144um. As Figure 5Shown is the overlapping result of the output spectral curve at the drop end of the cascaded dual-ring sensor and the flat-top filter, as shown in Equation (3). When the solution to be measured changes, the effective refractive index of the sensing ring will change, and the overall output spectral envelope at the drop end will shift. Correspondingly, the light intensity output in the passband of the filter will change. By detecting the change in intensity with a detector, the detection of biomolecular concentration is achieved.

[0058] P = ∫(P drop (λ) * P filter (λ))dλ (3)

[0059] As Figure 6 shown is the simulation diagram of the intensity detection sensitivity corresponding to different filter widths. When detecting power, the sensitivity of the sensor is related to the passband bandwidth of the filter. For the cascaded dual-ring sensor based on intensity detection, the output light intensity at its drop end is the overlapping integral of the output spectral curve at the drop end of the cascaded dual-ring sensor and the output spectral line of the flat-top filter 22. Its light intensity detection sensitivity is related to the passband width of the filter. The narrower the filter channel width, the more obvious the change of the overlapping integral with the refractive index, and the higher the sensitivity.

[0060] In the present invention, the 3dB bandwidth of the designed fourth-order series flat-top filter is 0.7nm, which can meet the requirements of high sensitivity. If a single-wavelength laser is used alone as the light source for sensing detection, although the sensitivity is high, the central wavelength is easily drifted by the surrounding environment interference, and the stability is poor. Therefore, the scheme of using a broadband light source plus a narrowband flat-top filter can ensure the detection stability while improving the sensitivity.

[0061] The advantage of using the flat-top filter is its temperature insensitivity. As Figure 7 shown is the simulation diagram of the stability against temperature drift when using a Gaussian filter and the fourth-order series flat-top filter of the present invention respectively. When the chip temperature changes, resulting in the overall effective refractive index offset of the sensor, the output spectral envelope at the drop end also shifts, while the shape of the spectral envelope remains unchanged. When using the flat-top filter, due to the flat-top characteristic of the passband, the shape of the filtered spectrum is not affected and the intensity remains unchanged, thus achieving the temperature-insensitive characteristic; while for the Gaussian filter, there is an obvious intensity change in the passband spectrum with the change of wavelength. When the output spectral envelope at the drop end shifts, the filtered spectrum is no longer at the center of the filter passband, so its intensity decreases significantly. Table 2 shows the refractive index temperature coefficients of different materials.

[0062] Table 2 Refractive Index Temperature Coefficients of Different Materials

[0063]

[0064] Refractive Index Temperature Coefficient of the Equivalent Refractive Index of TM Mode The value is approximately 1.8×10 -4 k -1 . When the temperature change is within 16K, the intensity deviation of the flat-top filter of the present invention is within 0.5%, while that of the Gaussian filter is within 5%. Therefore, the flat-top filter of the present invention has obvious advantages in terms of temperature insensitivity.

[0065] The above embodiments are used to explain the present invention rather than limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A microring sensor integrated with a high-order flattened filter, characterized in that, The sensor includes a fan-out packaged wafer, on which a light source LED array, a cascaded dual-ring sensing array chip, a detector array, a microfluidic channel device, and a voltage power supply are integrated; The cascaded dual-ring sensing array chip consists of an array of multiple cascaded dual-ring sensing structures; the cascaded dual-ring sensing structure includes an input grating coupler, a high-order series filter, a cascaded dual-ring sensor, a drop-end output grating coupler, and a pass-end output grating coupler; light is coupled into the input grating coupler by the light source LED array, filtered by the high-order series flat-topped filter, and sensing detection is realized in the cascaded dual-ring sensor part. Finally, the detection signal is output through the drop-end output grating coupler and the pass-end output grating coupler, and the signal is received by the detector array; the cascaded dual-ring sensor includes a sensing ring and a reference ring, and a biomolecular film is modified on the sensing ring; The described high-order series filter is formed by connecting n rings with different radii in series to achieve a channel rejection ratio greater than 30 dB and a free spectral range greater than or equal to 40 nm, resulting in an n-order series filter; in the n-order series filter, FSR 总 is the least common multiple of FSR i , where i = 1, 2, 3, …, n; FSR i is the free spectral range corresponding to each resonant ring; the values of the n FSR i satisfy FSR 总 ≥ 40 nm; According to and Determine the radius R of each resonant ring i and the resonance order m i ; To reduce losses, the ring radius needs to satisfy R ≥ 5um, that is, m ≥ 37, where n g is the group refractive index, λ is the central wavelength, and n eff is the equivalent refractive index; For the flat-topping of the filtering channel spectrum, the coupling coefficients k1 between the loop and the input / output waveguides, the coupling coefficient k2 between the loops, and the propagation constant k of the loop of the high-order series filter p satisfy the relationship where n is the number of series loops; The microfluidic channel device is aligned with the sensing ring, so that the liquid to be measured in the microfluidic channel flows through the sensing ring in each array; the voltage power supply applies a voltage to the cascaded dual-ring sensing array chip integrating the high-order flat-topped filter through a thermal electrode pair to achieve thermal tuning.

2. The micro-ring sensor integrated with a high-order flat-top filter according to claim 1, characterized in that, The microfluidic channel device includes a liquid inlet end, an outlet end, and a microfluidic channel passing above the sensing ring.

3. The micro-ring sensor integrating a high-order flat-top filter according to claim 1, characterized in that In the multiple cascaded dual-ring sensing structures, different biomolecular films are respectively modified on the sensing rings of each path, and a single microfluidic channel device can directly detect multiple biomolecular components on the sensing array chip.

4. The micro-ring sensor integrating a high-order flat-top filter according to claim 1, characterized in that, The high-order series filter replaces the traditional input and output waveguides with a Mach-Zehnder structure, and at the same time, a thermal electrode is added to the outer wall of the Herzen structure to adjust the deviation of the coupling coefficient caused by process errors; among them, the coupling coefficient k of the Mach-Zehnder part MZ The relationship with the original k1 is 5. The micro-ring sensor integrating a high-order flattened filter according to claim 1, wherein Thermal electrodes are prepared on the high-order series filter to finely adjust its equivalent refractive index, which is used to compensate for the passband top ripple phenomenon caused by the coupling-induced frequency shift effect.

6. The micro-ring sensor integrated with a high-order flat-top filter according to claim 1, characterized in that, The fan-out packaged wafer is prepared using an epoxy resin material and becomes an extended part of the silicon wafer; electrodes are prepared on the fan-out packaged wafer to achieve electrical packaging and complete the alignment packaging of the microfluidic channel device.

7. The microring sensor integrated with a high-order flattened filter according to claim 1, wherein The light source LED array and the detector array are fixed on the cascaded dual-ring sensing array chip integrating the high-order flat-topped filter in a flip-chip manner; the light source LED array is aligned with the input grating coupler array, and the detector array is aligned with the drop-end output grating coupler array and the pass-end grating coupler array.

8. The microring sensor integrated with a high-order flattened filter according to claim 1, characterized in that The 3dB bandwidth of the high-order series filter is related not only to the radius of each ring but also to the coupling coefficient; when the radii of the four series-connected rings are determined, the 3dB bandwidth of the filter is finely adjusted by adjusting the coupling ratio of the coupling region.

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