A high-resolution on-chip integrated computational spectrometer for a defective multimode waveguide

Abstract

The application provides a high-resolution on-chip integrated computing spectrometer of a defective multimode waveguide, which comprises an input waveguide module, a defective multimode waveguide and an output waveguide array which are sequentially connected in the order of the light direction, the input waveguide module is internally provided with a slit focusing lens assembly and an electrothermal light adjusting switch assembly, the edge of the defective multimode waveguide is provided with a plurality of scattering defect structures which are uniformly distributed in position, randomly shaped and randomly deep and wide, the width of the defective multimode waveguide is greater than one or more times of the working wavelength of the high-resolution on-chip integrated computing spectrometer, and the output waveguide array is internally provided with a single-mode optical waveguide array which is composed of a plurality of single-mode optical waveguides. The application has the beneficial effects of being able to reduce the size, being able to realize precise regulation and control of the light output position by a small number of electrodes, and being able to improve the scattering disorder degree of the light wave in the limited size.

Description

Technical Field

[0001] This invention relates to the field of spectrometer technology, and more specifically to a high-resolution on-chip integrated computational spectrometer with a defective multimode waveguide. Background Technology

[0002] Spectroscopic analysis technology achieves accurate and rapid non-contact sensing and detection through emission, absorption, and scattering, offering unparalleled advantages in biochemical sensing and materials analysis. Traditional discrete-device spectrometers, whether due to beam control units, spectral dispersive units, or interferometry units, inevitably suffer from large size, heavy weight, and high cost. Spectrometers have a wide range of applications, but existing commercial spectrometers are limited by environmental constraints. On-chip spectrometers, as a crucial component of spectrometer miniaturization, offer advantages such as small size and greater portability. Therefore, miniaturization and chip-based design are inevitable development trends for spectrometers. After 30 years of development, on-chip photonic integration has become a significant technological approach for spectrometer miniaturization.

[0003] Currently, most spatial spectrometers are dispersive spectrometers based on grating dispersion. These discrete devices typically have large sizes because they require a certain optical path to accumulate dispersion. Existing on-chip integrated spectrometers can be broadly classified into four categories based on their operating principles: dispersive spectrometers, filtered spectrometers, Fourier transform spectrometers, and computational reconstruction spectrometers. Dispersive and filtered spectrometers were the first to be proposed. These two types of spectrometers rely on a one-to-one spectral-spatial mapping for dispersion. Common techniques include arrayed waveguide gratings, shallow-etched gratings, and micro-ring arrays. While this mapping method is intuitive, achieving high resolution often requires a large device size.

[0004] Around 2000, on-chip Fourier transform spectrometers began to emerge. These spectrometers have a much faster scanning speed than dispersive spectrometers, require fewer optical components, and rely primarily on interferometers, resulting in better signal-to-noise ratios. The size of on-chip Fourier transform spectrometers is mainly limited by the optical path difference and the number of interferometers. While there have been improvements in size compared to the aforementioned spectrometers, further reduction remains challenging. Compared to the aforementioned spectrometers, computational reconstruction spectrometers are characterized by a more complex one-to-many spectral-spatial mapping. Unlike dispersive or filtered spectrometers, which directly obtain the original spectrum, computational spectrometers require complex reconstruction algorithms to decode the original spectrum, but this significantly improves space utilization and device integration. This one-to-many spectral-spatial mapping can be mathematically represented as a matrix transforming spectral space into physical space. Common techniques include on-chip disordered scattering structures and multimode helical waveguides. Most scattering structures have fixed, unknown inputs, resulting in low utilization of the scattering structure and limitations in bandwidth.

[0005] However, most scattering structures have fixed unknown inputs, resulting in low utilization of the scattering structure and thus limitations in bandwidth. Moreover, the speckle formed by such disordered scattering structures comes from multiple scatterings within the structure, leading to significant loss of the spectrometer in the vertical direction. The speckle disorder of multimode spiral waveguide structures mainly comes from evanescent coupling and mode aliasing between waveguides, requiring a longer size and path to provide sufficient disorder. Summary of the Invention

[0006] To address the problems in existing technologies, this invention provides a high-resolution on-chip integrated computational spectrometer with a defective multimode waveguide. This spectrometer can reduce its size while achieving precise control of the light output position by controlling the heating level with a few electrodes. Furthermore, it can maximize the scattering disorder of light waves in the defective multimode waveguide within a limited size, solving the problems in existing technologies where disordered scattering structures lead to significant vertical losses in the spectrometer, multimode spiral waveguides require long dimensions and paths to provide sufficient disorder, and the low utilization rate of disordered scattering structures results in limited bandwidth.

[0007] This invention provides a high-resolution on-chip integrated computational spectrometer with a defective multimode waveguide, comprising a chip platform and an input waveguide module, a defective multimode waveguide, and an output waveguide array disposed within the chip platform. The input waveguide module, the defective multimode waveguide, and the output waveguide array are sequentially connected along the illumination direction. The input waveguide module contains a slit focusing lens assembly and an electrothermal dimming switch assembly that cooperate with each other. The edge of the defective multimode waveguide has multiple scattering defect structures with uniformly distributed positions, random shapes, and random depths and widths. The width of the defective multimode waveguide is greater than one or more times the operating wavelength of the high-resolution on-chip integrated computational spectrometer. The output waveguide array contains a single-mode waveguide array composed of multiple single-mode waveguides. The slit focusing lens assembly and the electrothermal dimming switch assembly can adjust the position of the light wave output from the input waveguide module to the defective multimode waveguide by heating and focusing. The scattering defect structures can improve the scattering disorder of the light wave passing through the defective multimode waveguide.

[0008] The present invention is further improved in that the chip platform is a silicon-on-insulator platform, including a silicon dioxide cladding layer, a waveguide mounting silicon layer, a silicon dioxide layer and a silicon substrate layer from top to bottom. The electrothermal dimming switch assembly is disposed in the silicon dioxide cladding layer, and the slit focusing lens assembly, the defective multimode waveguide and the output waveguide array are all disposed in the waveguide mounting silicon layer.

[0009] The present invention is further improved in that the thickness of the silicon layer on the waveguide is 220 nm.

[0010] The present invention is further improved in that the electrothermal dimming switch assembly includes a metal electrode and a serpentine thermal resistor. The metal electrode is electrically connected to the serpentine thermal resistor. The serpentine thermal resistor is laid out in a serpentine shape within the silicon dioxide layer. The serpentine thermal resistor as a whole forms two sets of matching triangular heating regions.

[0011] The present invention is further improved in that the slit focusing lens assembly includes two sets of dimming slits respectively disposed on both sides of the serpentine thermal resistor along the illumination direction. The dimming slits are generally concave on one side and are composed of multiple parallel dimming slits of the same width. The length of the dimming slits gradually decreases from both ends to the middle of the dimming slits. The two sets of dimming slits and the serpentine thermal resistor together form a concave lens.

[0012] The present invention is further improved in that the incident waveguide of the input waveguide module is a single-mode waveguide, wherein the width of the single-mode waveguide is 500nm.

[0013] The present invention is further improved in that the length of the defective multimode waveguide along the illumination direction is ≥10µm.

[0014] The present invention is further improved in that the shape of the scattering defect structure includes an arc groove type and a polygon.

[0015] The present invention is further improved in that the depth and width of the scattering defect structure are both less than half the width of the defective multimode waveguide.

[0016] In a further improvement to the present invention, an adiabatic tapered waveguide is provided within the output waveguide array, and the defective multimode waveguide is connected to the single-mode optical waveguide array through the adiabatic tapered waveguide.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a high-resolution on-chip integrated computational spectrometer with a defective multimode waveguide. By setting up an input waveguide module, a defective multimode waveguide, and an output waveguide array that cooperate with each other within the high-resolution on-chip integrated computational spectrometer, and by including a slit focusing lens assembly and an electrothermal dimming switch assembly within the input waveguide module, the slit focusing lens assembly and the electrothermal dimming switch assembly can adjust the position of the light wave output from the input waveguide module to the defective multimode waveguide through heating and focusing. The scattering defect structure can improve the scattering disorder of the light wave passing through the defective multimode waveguide. This allows for the reduction of the size of the high-resolution on-chip integrated computational spectrometer while achieving precise control of the light output position by controlling the heating degree with a few electrodes. By adjusting the light output position through electrodes while maintaining resolution and reducing losses, the working bandwidth of the high-resolution on-chip integrated computational spectrometer can be broadened. Moreover, the scattering defect structure set in the defective multimode waveguide can maximize the scattering disorder of light waves in the defective multimode waveguide within a limited size, and can also significantly reduce the size of the high-resolution on-chip integrated computational spectrometer. The output waveguide array contains a single-mode waveguide array composed of multiple single-mode waveguides, which can collect light intensity at different positions. This solves the problems in the prior art where disordered scattering structures lead to large losses in the vertical direction of the spectrometer, multimode spiral waveguides require long dimensions and paths to provide sufficient disorder, and the low utilization rate of disordered scattering structures results in small bandwidth. Attached Figure Description

[0018] To more clearly illustrate the solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a top view of the high-resolution on-chip integrated computational spectrometer of the defective multimode waveguide of the present invention;

[0020] Figure 2 This is a three-dimensional view of the high-resolution on-chip integrated computational spectrometer for the defective multimode waveguide of the present invention;

[0021] Figure 3 This is a thermal field distribution diagram of the electrothermal dimming switch component area of ​​the present invention;

[0022] Figure 4 This is a simulated optical field distribution diagram of the defective multimode waveguide region of the present invention;

[0023] Figure 5 The image shows a simulated speckle pattern output by a high-resolution on-chip integrated computational spectrometer for the defective multimode waveguide of this invention.

[0024] Figure 6 The spectral correlation function curve of the high-resolution on-chip integrated computational spectrometer for the defective multimode waveguide of this invention is shown.

[0025] Figure 7 Reconstructed spectra of some structures using a high-resolution on-chip integrated computational spectrometer for inventing defective multimode waveguides.

[0026] The figure shows the spectral intensity fingerprint of the input waveguide module, 11 slit focusing lens assembly, 12 electrothermal dimming switch assembly, 2 defective multimode waveguide, 21 scattering defect structure, 3 output waveguide array, and 4 output waveguide array. Detailed Implementation

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof in the specification, claims and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0030] like Figure 1-7As shown, the present invention provides a high-resolution on-chip integrated computational spectrometer with a defective multimode waveguide, comprising a chip platform and an input waveguide module 1, a defective multimode waveguide 2, and an output waveguide array 3 disposed within the chip platform. The input waveguide module 1, the defective multimode waveguide 2, and the output waveguide array 3 are sequentially connected along the illumination direction. The input waveguide module 1 is provided with a slit focusing lens assembly 11 and an electrothermal dimming switch assembly 12 that cooperate with each other. The edge of the defective multimode waveguide 2 is provided with multiple scattering defect structures 21 that are uniformly distributed in position, randomly shaped, and randomly deep and wide. The width of the defective multimode waveguide 2 is greater than one or more times the operating wavelength of the high-resolution on-chip integrated computational spectrometer. The output waveguide array 3 is provided with a single-mode optical waveguide array composed of multiple single-mode optical waveguides. In this embodiment, the slit focusing lens assembly and the electrothermal dimming switch assembly can adjust the position of the light wave output from the input waveguide module to the defective multimode waveguide by heating and focusing. The scattering defect structure can improve the scattering disorder of the light wave passing through the defective multimode waveguide. This allows for precise control of the light output position by controlling the heating degree with a few electrodes while reducing the size of the high-resolution on-chip integrated computational spectrometer. It can also reduce the vertical scattering loss generated at the center of the multimode waveguide and broaden the working bandwidth of the high-resolution on-chip integrated computational spectrometer. Moreover, the scattering defect structure set in the defective multimode waveguide can maximize the scattering disorder of the light wave in the defective multimode waveguide within a limited size, and can also significantly reduce the size of the high-resolution on-chip integrated computational spectrometer. The output waveguide array is equipped with a single-mode waveguide array composed of multiple single-mode waveguides, which can collect the light intensity at different positions.

[0031] In this embodiment, a defective multimode waveguide with localized thermal modulation is used instead of the traditional Mach-Zehnder cascade structure to achieve the optical switching function. The serpentine distribution of the heating wires in the electrothermal optical switching component ensures that the local refractive index change meets the requirements, while maintaining a smaller size than the Mach-Zehnder cascade optical switch array, resulting in a more integrated overall device. The width of the defective multimode waveguide is greater than one or more times the operating wavelength of the high-resolution on-chip integrated computational spectrometer, ensuring a sufficient number of modes. Superimposing multiple scattering defect structures on this basis results in more complex mode aliasing, ultimately increasing the disorder of the output speckle. A wider defective multimode waveguide is more beneficial for the presence of multiple modes. The coexistence of different patterns leads to a more chaotic speckle pattern, improving the resolution of the spectrometer. However, in order to reduce the effective size, increase the bandwidth, and improve the utilization rate of the device size, the width of the scattering region of the defective multimode waveguide is determined by the output range of the front-end electrothermal dimming switch component. The scattering defect structure at the edge of the defective multimode waveguide is uniformly distributed, with variations in shape and overall width. This ensures that the wave vector changes direction after passing through it, while minimizing return loss. The output end of the defective multimode waveguide is connected to the single-mode optical waveguide array via an adiabatic tapered waveguide. After outputting to the grating coupler, the light intensity distribution is detected by optical fiber as a spectral fingerprint. The adiabatic tapered waveguide, i.e., the taper-type waveguide, can reduce reflection loss.

[0032] like Figure 2 As shown, the chip platform is a silicon-on-insulator platform, including a silicon dioxide cladding layer, a waveguide mounting silicon layer, a silicon dioxide layer and a silicon substrate layer from top to bottom. The electrothermal dimming switch assembly 12 is disposed within the silicon dioxide cladding layer. The slit focusing lens assembly 11, the defective multimode waveguide 2 and the output waveguide array 3 are all disposed within the waveguide mounting silicon layer, wherein the thickness of the waveguide mounting silicon layer is 220nm.

[0033] An optical waveguide is a dielectric device that guides the propagation of light waves; it is also called a dielectric waveguide. There are two main types of optical waveguides: one is integrated optical waveguides, including planar (thin-film) dielectric waveguides and strip dielectric waveguides, which are usually part of optoelectronic integrated devices (or systems), hence the name integrated optical waveguides; the other is cylindrical optical waveguides, commonly called optical fibers (see optical fibers). An optical waveguide is a guiding structure for transmitting optical frequency electromagnetic waves, made of an optically transparent medium (such as quartz glass). The transmission principle of an optical waveguide differs from that of a closed metal waveguide. At the interface between media with different refractive indices, the total internal reflection phenomenon of electromagnetic waves confines the light waves to the waveguide and a limited area around it. In this embodiment, a high-resolution on-chip integrated computational spectrometer is realized using an optical waveguide.

[0034] like Figure 1-3As shown, the input waveguide module 1 has a single-mode waveguide with a width of 500 nm. The electrothermal dimming switch assembly 12 includes a metal electrode and a serpentine thermal resistor. The metal electrode is electrically connected to the serpentine thermal resistor, which is laid out in a serpentine pattern within the silicon dioxide cladding layer. The serpentine thermal resistor forms two sets of matching triangular heating regions. The slit focusing lens assembly 11 includes two sets of dimming slits arranged on both sides of the serpentine thermal resistor along the illumination direction. The dimming slits are concave on one side and consist of multiple parallel dimming slits of uniform width. The length of the dimming slits gradually decreases from both ends to the middle. The two sets of dimming slits and the serpentine thermal resistor together form a concave lens. In this embodiment, the 500 nm width of the single-mode waveguide ensures a uniform light field distribution when the 1550 nm single-mode incident light enters the taper region, and the optical path difference from the incident port to the slit focusing lens assembly region is fixed. The purpose of the double-slit focusing lens assembly is to transform the input single-mode divergent light wave vector into a wave vector along the waveguide propagation direction. In subsequent control processes, local thermal tuning ensures relative focusing of the output light. Different wavelengths are focused to different positions due to local refractive index differences within the thermally tuned region. Specifically, the uniform, triangular-like heating region combined with the phase gradient focusing lens formed by the scattering defect structure causes the fundamental mode to be deflected as a whole after passing through this region. The light is then focused at the input end of the defective multimode waveguide region by the slit focusing lens assembly. Adjusting the heating voltage adjusts the deflection angle of the light transmission, changing the exit position, thereby expanding the speckle dimension and increasing the overall bandwidth of the spectrometer.

[0035] like Figure 1-3 As shown, the length of the defective multimode waveguide 2 is ≥10µm, and the shape of the scattering defect structure 21 includes arc-shaped grooves and polygons. The depth and width of the scattering defect structure 21 are both less than half the width of the defective multimode waveguide 2. In this embodiment, the width of the defective multimode waveguide region is ≥10µm to ensure the diversity of excited modes. The scattering defect structures are distributed at the edge of the defective multimode waveguide to reduce the vertical scattering loss generated at the center of the defective multimode waveguide. The position and size of the scattering defect structures are random, and a local optimal distribution can be obtained by topology optimization.

[0036] like Figure 1-3 As shown, the output waveguide array 3 is also equipped with an adiabatic tapered waveguide. The defective multimode waveguide 2 is connected to the single-mode optical waveguide array through the adiabatic tapered waveguide, which can reduce the mode loss of the final output.

[0037] like Figure 4 The image shows the simulated optical field distribution within the defective multimode waveguide and the corresponding output speckle pattern, obtained by exciting the defective multimode waveguide at different input positions in the 1550nm band in TEO mode according to the present invention. Figure 5As shown, when light waves enter the defective multimode waveguide region from the input waveguide module, they initially excite multiple modes. During propagation, disordered scattering occurs in the scattering defect structure, generating a series of wavelength-dependent speckles, thus obtaining the specificity of the output. Based on this, we can analyze and calculate the original input spectrum using reconstruction algorithms such as compressed sensing. Furthermore, when light waves enter the defective multimode waveguide region from the input waveguide module through different locations, they excite different fields and modes. This leads to different final speckles produced along the same path, increasing the spectral bandwidth and improving the applicability of the spectrometer.

[0038] like Figure 5 As shown, this figure simulates the power speckle distribution at the output end of a light wave that enters the defective multimode waveguide region from the input waveguide module through nine different locations. The excited light field propagates and is scattered within the defective multimode waveguide with a scattering defect structure. With a basis function of 1, this can be directly considered as the transmission matrix of the spectrometer. The horizontal axis represents the wavelength channels, and the vertical axis represents the detection channels. The color intensity represents the optical power. This speckle pattern is directly related to the performance of the spectrometer. Based on the spectral correlation function... The spectral correlation function curve of the spectrometer can be plotted, such as... Figure 6 As shown.

[0039] like Figure 6 As shown, C(δλ) represents the spectral correlation, δλ represents the wavelength interval, and C i Represents the detector channel, I(λ, C) i () indicates that the wavelength channel is λ and the detection channel is C. i The power level at that time, <…> λ Take the sign of the average wavelength, <…> i The sign of the average value for the detection channels is taken. The resolution of the spectrometer can be estimated by the half-width at half-maximum (HWHM) of the spectral correlation function, representing the minimum wavelength separation required to reduce the correlation by half. The figure shows that the theoretical predicted spectral resolution of this device is 8.25 nm. To further improve the resolution, the number of scattering defect structures can be increased, or the size and shape of the defect structures can be optimized.

[0040] like Figure 7 As shown in the figure, this graph illustrates the spectrometer's recovery of a preset spectral signal. The detected output signal is used as a unique fingerprint, and a compressed sensing algorithm is employed to reconstruct the input spectral signal. The results demonstrate that the spectrometer can reconstruct and recover both discrete and continuous spectra, and can accurately recover spectral information at different wavelengths and intensities. Its operating bandwidth covers 200 nm, from 1450 nm to 1650 nm.

[0041] As can be seen from the above, this invention provides a high-resolution on-chip integrated computational spectrometer with a defective multimode waveguide. By incorporating a cooperating input waveguide module, a defective multimode waveguide, and an output waveguide array within the high-resolution on-chip integrated computational spectrometer, and including a slit focusing lens assembly and an electrothermal dimming switch assembly within the input waveguide module, the position of the light wave output from the input waveguide module to the defective multimode waveguide can be adjusted through heating and focusing. The scattering defect structure can improve the scattering disorder of the light wave passing through the defective multimode waveguide. This allows for a reduction in the size of the high-resolution on-chip integrated computational spectrometer while achieving precise control of the light output position by controlling the heating level with a few electrodes, thus maintaining resolution and... By adjusting the light output position through electrodes while reducing losses, the working bandwidth of the high-resolution on-chip integrated computational spectrometer can be broadened. Moreover, the scattering defect structure set in the defective multimode waveguide can maximize the scattering disorder of light waves in the defective multimode waveguide within a limited size, and can also significantly reduce the size of the high-resolution on-chip integrated computational spectrometer. The output waveguide array contains a single-mode waveguide array composed of multiple single-mode waveguides, which can collect light intensity at different positions. This solves the problems in the prior art where disordered scattering structures lead to large losses in the vertical direction of the spectrometer, multimode spiral waveguides require long dimensions and paths to provide sufficient disorder, and disordered scattering structures have low utilization rates, resulting in small bandwidth.

[0042] The specific embodiments described above are preferred embodiments of the present invention and are not intended to limit the specific scope of the present invention. The scope of the present invention includes, but is not limited to, these specific embodiments. All equivalent changes made in accordance with the present invention are within the protection scope of the present invention.

Claims

1. A high-resolution on-chip integrated computational spectrometer for defective multimode waveguides, characterized in that: The system includes a chip platform and an input waveguide module, a defective multimode waveguide, and an output waveguide array disposed within the chip platform. The input waveguide module, the defective multimode waveguide, and the output waveguide array are sequentially connected along the illumination direction. The input waveguide module contains a slit focusing lens assembly and an electrothermal dimming switch assembly that cooperate with each other. The edge of the defective multimode waveguide has multiple scattering defect structures with uniformly distributed positions, random shapes, and random depths and widths. The width of the defective multimode waveguide is greater than one or more times the operating wavelength of the high-resolution on-chip integrated computational spectrometer. The output waveguide array contains a single-mode waveguide array composed of multiple single-mode waveguides. The slit focusing lens assembly and the electrothermal dimming switch assembly can adjust the position of the light wave output from the input waveguide module to the defective multimode waveguide by heating and focusing. The scattering defect structures can improve the scattering disorder of the light wave passing through the defective multimode waveguide.

2. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 1, characterized in that: The chip platform is a silicon-on-insulator platform, comprising, from top to bottom, a silicon dioxide cladding layer, a waveguide mounting silicon layer, a silicon dioxide layer, and a silicon substrate layer. The electrothermal dimming switch assembly is disposed within the silicon dioxide cladding layer, and the slit focusing lens assembly, the defective multimode waveguide, and the output waveguide array are all disposed within the waveguide mounting silicon layer.

3. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 2, characterized in that: The thickness of the silicon layer on the waveguide is 220 nm.

4. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 2 or 3, characterized in that: The electrothermal dimming switch assembly includes a metal electrode and a serpentine thermal resistor. The metal electrode is electrically connected to the serpentine thermal resistor, which is laid out in a serpentine shape within the silicon dioxide coating layer. The serpentine thermal resistor as a whole forms two sets of matching triangular heating regions.

5. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 4, characterized in that: The slit focusing lens assembly includes two sets of dimming slits respectively disposed on both sides of the serpentine thermal resistor along the illumination direction. The dimming slits are generally concave on one side and are composed of multiple parallel dimming slits of the same width. The length of the dimming slits gradually decreases from both ends to the middle of the dimming slits. The two sets of dimming slits and the serpentine thermal resistor together form a concave lens shape.

6. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 5, characterized in that: The input waveguide module has an incident waveguide that is a single-mode waveguide with a width of 500 nm.

7. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 6, characterized in that: The length of the defective multimode waveguide along the illumination direction is ≥10µm.

8. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 7, characterized in that: The shapes of the scattering defect structures include arc-shaped grooves and polygons.

9. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 8, characterized in that: The depth and width of the scattering defect structure are both less than half the width of the defective multimode waveguide.

10. The high-resolution on-chip integrated computational spectrometer with defective multimode waveguides according to claim 9, characterized in that: The output waveguide array is further provided with an adiabatic tapered waveguide, and the defective multimode waveguide is connected to the single-mode optical waveguide array through the adiabatic tapered waveguide.

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