CN119309673A - Wide-spectrum integrated spectrometer based on gradient photonic crystal dispersion - Google Patents
Wide-spectrum integrated spectrometer based on gradient photonic crystal dispersion Download PDFInfo
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- CN119309673A CN119309673A CN202411456915.3A CN202411456915A CN119309673A CN 119309673 A CN119309673 A CN 119309673A CN 202411456915 A CN202411456915 A CN 202411456915A CN 119309673 A CN119309673 A CN 119309673A
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- 239000004038 photonic crystal Substances 0.000 title claims abstract description 53
- 239000006185 dispersion Substances 0.000 title claims abstract description 34
- 238000001228 spectrum Methods 0.000 title claims abstract description 31
- 230000003287 optical effect Effects 0.000 claims abstract description 89
- 239000011159 matrix material Substances 0.000 claims description 3
- 239000013078 crystal Substances 0.000 abstract description 15
- 238000013461 design Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 230000003595 spectral effect Effects 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000003491 array Methods 0.000 description 4
- 238000009825 accumulation Methods 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
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Abstract
The invention discloses a wide spectrum integrated spectrometer based on gradual change photon crystal dispersion, an optical chip comprises a beam splitter, an optical waveguide and gradual change photon crystals, wherein the optical waveguide comprises an input optical waveguide and an output optical waveguide, the input end of the beam splitter is connected with the input optical waveguide, a plurality of output ends of the beam splitter are respectively connected with one end of the output optical waveguide, and the other end of each output optical waveguide is respectively connected with the gradual change photon crystals. The CMOS detector is used for reconstructing the spatial distribution of scattered light intensity leaked from the gradual change photon crystal to obtain an input spectrum. According to the wide spectrum integrated spectrometer based on gradual change photonic crystal dispersion, the photonic crystal is formed by designing the dispersion hole chirp array at the side edge of the waveguide, and high-precision spectrum resolution is realized in a small volume by utilizing the sensitive angular dispersion of the photonic crystal and the wavelength guidance of a gradual change structure in space.
Description
Technical Field
The invention relates to a wide spectrum integrated spectrometer based on gradual change photonic crystal dispersion, and belongs to the technical field of spectrum analysis.
Background
Spectrometers based on dispersive elements such as gratings are a traditional design method of integrated spectrometers, but because the spectrometers require accumulation of optical paths, the size is difficult to further reduce under the condition of ensuring a certain wavelength resolution. The integrated spectrometer based on filtering obtains spectrum information by detecting the light intensity output by different filter channels. In order to meet the wider spectrum monitoring range, enough filter structures need to be designed, and the spectrum monitoring range is limited by the free spectrum range of the resonance structure, so that the method is difficult to expand to a wide spectrum. The spectrometer based on hole scattering does not need to guide monochromatic light to a single position, the spatial distribution of wavelength information is aliased, the spectral resolution is realized by a calculation reconstruction method, and the spectrometer can have higher resolution in a smaller volume, but all adopt disordered structures, have no standard design specification, have higher difficulty in repeated processing and limit the practical application of the spectrometer.
The photonic crystal composed of the periodically arranged scattering hole array has a super-prism effect, and when the angle of incident light approaches a specific angle, a small change in the incident angle causes a significant change in the refraction angle. However, excitation of photonic crystal superprisms often requires complex structures for beam shaping, while the response bandwidth is narrow, typically only tens of nanometers, and also requires some accumulation of optical paths to convert angular dispersion to spatial dispersion, which has not been a problem for spectrometer designs.
Therefore, those skilled in the art need to overcome the problems of Kong Sanshe spectrometer that the disordered structure has no design specifications, processing difficulties, and the super-prism effect of ordered scattering hole photonic crystals requires beam shaping, bandwidth narrowing, and optical path accumulation.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a wide spectrum integrated spectrometer based on gradual change photonic crystal dispersion, which designs a scattering hole array which is orderly arranged and periodically gradually changed, and utilizes the super prism effect of photonic crystals and the gradual change period to guide the scattering of light with different wavelengths so as to realize effective space dispersion in a compact volume.
The technical scheme adopted by the invention is as follows:
A wide spectrum integrated spectrometer based on gradual change photon crystal dispersion comprises an optical chip and a CMOS detector.
The optical chip comprises a beam splitter, an optical waveguide and a gradual change photon crystal, wherein the optical waveguide comprises an input optical waveguide and an output optical waveguide, the input end of the beam splitter is connected with the input optical waveguide, a plurality of output ends of the beam splitter are respectively connected with one end of the output optical waveguide, and the other end of each output optical waveguide is respectively connected with the gradual change photon crystal.
The CMOS detector is used for reconstructing the spatial distribution of scattered light intensity leaked from the gradual change photon crystal to obtain an input spectrum.
Preferably, the CMOS detector is placed at the bottom or side of the optical chip.
Preferably, the beam splitter is used for splitting incident light in the input optical waveguide into a plurality of split light beams with different wavelengths, and coupling the split light beams with different wavelengths into corresponding output optical waveguides respectively.
Preferably, the output optical waveguide adopts a single-mode optical waveguide, and the width of the single-mode optical waveguide is determined by the wavelength of the transmitted beam splitting light.
Preferably, the graded photonic crystal comprises crystal lattices, and the crystal lattices are distributed in an array. And the lattice is provided with a scattering hole array consisting of scattering holes arranged in a 2x2 matrix.
Preferably, the period dx of the scattering hole array along the extending direction of the waveguide multiplied by the effective refractive index of the output optical waveguide is 0.5-0.7,Indicating the wavelength of the split light in the output optical waveguide.
Preferably, the period dx of the lattice of the graded photonic crystal along the extending direction of the waveguide is graded from big to small, the maximum value of the period dx of the lattice of the graded photonic crystal along the extending direction of the waveguide is determined by the longest wavelength of the split light in the output optical waveguide, and the minimum value is determined by the shortest wavelength of the split light in the output optical waveguide.
Preferably, the period dx of the scattering hole array along the extending direction of the waveguide is expressed as follows:
Wherein, Indicating the effective refractive index of the output optical waveguide,The wavelengths of the split light within the output optical waveguide.
Preferably, the ratio of the diameter D of the scattering holes of the lattice to the period dx of the array of scattering holes along the direction of extension of the waveguide is 0.6.
Preferably, the ratio of the period dy of the scattering hole array perpendicular to the extending direction of the waveguide to the period dx of the scattering hole array along the extending direction of the waveguide is 1.5.
The wide spectrum integrated spectrometer based on gradual change photonic crystal dispersion has the beneficial effects that the photonic crystal is formed by designing the dispersion hole chirp array at the side edge of the waveguide, and high-precision spectrum resolution is realized in a small volume by utilizing the sensitive angular dispersion of the photonic crystal and the wavelength guidance of a gradual change structure in space.
In order to further widen the spectral response range, input light is coupled into different optical waveguides respectively by using a beam splitter, and the photonic crystal at the side of each optical waveguide realizes spatial dispersion on light in a corresponding wavelength range. And detecting scattered light intensity distribution on the side surface or the bottom surface of the emergent light of the photonic crystal by using a CMOS detector, and reconstructing a spectrum by using the light intensity distribution. The integrated spectrometer design overcomes the problem that the resolution precision of the traditional spectrometer is limited by volume, and realizes the integrated spectrometer with high resolution capability and wide spectrum range.
Further, the invention is smaller, less costly, and maintains a higher spectral resolution and a wider spectral response range than conventional large spectrometers.
Furthermore, compared with other integrated spectrometers, the invention overcomes the problem of limited spectral resolution capacity of the volume, and maintains higher performance index in a compact volume.
Furthermore, compared with an integrated reconstruction spectrometer based on scattering, the integrated reconstruction spectrometer overcomes the problem that a disordered structure has no design specification, and is convenient for batch processing.
Furthermore, compared with other photonic crystal dispersion structures, the photonic crystal dispersion structure disclosed by the invention realizes large-angle dispersion and greatly reduces the optical path required to be accumulated by utilizing the waveguide side coupling and the periodic gradual change structure.
Furthermore, by adjusting the number of waveguides and the structural parameters of the photonic crystal, the invention can be applied to various wave bands such as near ultraviolet, visible light, near infrared and the like, and can meet the application requirements of different occasions.
Drawings
FIG. 1 is a schematic diagram of the structure of an integrated spectrometer of the present invention.
Fig. 2 is a schematic top view of an output optical waveguide and graded photonic crystal.
Detailed Description
The following description of the embodiments of the present invention will be made more apparent and fully by reference to the accompanying drawings, in which embodiments of the invention are shown, and in which it is evident that the embodiments shown are only some, but not all embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without any inventive effort, are intended to be within the scope of the present invention.
The invention will be further described with reference to specific examples.
Example 1:
This embodiment describes a broad spectrum integrated spectrometer based on graded photonic crystal dispersion, as shown in fig. 1, comprising an optical chip 1 and a CMOS detector 2.
The optical chip 1 comprises a beam splitter 101, an optical waveguide and a graded photonic crystal 102, wherein the optical waveguide comprises an input optical waveguide 103 and an output optical waveguide 104, the input end of the beam splitter 101 is connected with the input optical waveguide 103, a plurality of output ends of the beam splitter 101 are respectively connected with one end of the output optical waveguide 104, and the other end of each output optical waveguide 104 is respectively connected with the graded photonic crystal 102.
The CMOS detector 2 is placed at the bottom or side of the optical chip 1.
The invention can effectively excite the super-prism effect by the way of coupling the output optical waveguide 104 to the side surface of the gradual change photonic crystal 102, so that the propagation angle of light in the photonic crystal 102 is changed rapidly along with the wavelength, and then the obvious wavelength distinction can be realized in a very small volume.
Secondly, a plurality of graded photonic crystals 102 and output optical waveguides 104 are designed simultaneously and connected in parallel by using a beam splitter 101, thereby realizing a larger working bandwidth.
Further, the beam splitter 101 is configured to split incident light in the input optical waveguide 103 into a plurality of split light beams with different wavelengths, and couple the split light beams with different wavelengths into corresponding output optical waveguides 104, respectively.
Further, the CMOS detector 2 is configured to reconstruct the spatial distribution of the scattered light intensity leaked from the bottom surface or the side surface of the graded photonic crystal 102, so as to obtain an input spectrum.
Further, the number of the beam splitters 101 is determined by the bandwidth of the detection wavelength of the spectrometer.
Further, the output optical waveguide 104 employs a single-mode optical waveguide, and the width of the single-mode optical waveguide is determined by the wavelength of the transmitted beam-splitting light.
Further, the graded photonic crystal 102 is disposed on one side of the output optical waveguide 104, and energy of the split beam is coupled into the graded photonic crystal 102 when propagating in the output optical waveguide 104.
Further, as shown in fig. 2, the graded photonic crystal 102 includes a lattice 1021, and the lattice 1021 is distributed in an array.
Further, the lattice 1021 is provided with a scattering hole array formed by scattering holes 1022 arranged in a 2x2 matrix.
Further, the period dx of the scattering hole array along the extending direction of the waveguide of the lattice 1021 multiplied by the effective refractive index of the output optical waveguide 104 is 0.5-0.7Within a range (preferably 0.6),Indicating the wavelength of the split light within the output optical waveguide 104, has a significant dispersive effect.
Further, the period dx of the scattering hole array of the lattice 1021 in the graded photonic crystal 102 along the extending direction of the waveguide is graded from first to last, the maximum value of the period dx of the scattering hole array along the extending direction of the waveguide is determined by the longest wavelength of the split light in the output optical waveguide 104, and the minimum value is determined by the shortest wavelength of the split light in the output optical waveguide 104, so that the graded photonic crystal has remarkable dispersion effect.
Further, the period dx of the scattering hole array along the extending direction of the waveguide is expressed as follows:
Wherein, Indicating the effective refractive index of the output optical waveguide 104,The wavelength of the split light within the output optical waveguide 104.
Further, the ratio of the diameter D of the scattering holes 1022 of the lattice 1021 to the period dx of the scattering hole array along the extending direction of the waveguide is 0.6.
Further, the ratio of the period dy of the scattering hole array perpendicular to the extending direction of the waveguide of the lattice 1021 to the period dx of the scattering hole array along the extending direction of the waveguide is 1.5.
Further, the optical chip 1 further includes a substrate layer 105, the top surface of the substrate layer 105 is provided with a beam splitter 101, an optical waveguide, and a graded photonic crystal 102, and the substrate layer is made of silicon dioxide.
Example 2:
The wavelength range from near ultraviolet, visible light to near infrared can be covered by modifying the optical waveguide width, the beam splitting number of the beam splitter and the scattering array period size in the graded photonic crystal for different target wavelength ranges of the integrated spectrometer.
One embodiment of a graded photonic crystal:
The gradual change photon crystal adopts a basal layer of silicon dioxide material, adopts a waveguide of silicon nitride light material, the incident light is quasi-TE mode polarized in the optical waveguide, namely, the polarization direction of an electric field is parallel to a material interface, the wave vector of the optical waveguide along the propagation direction maintains a certain proportion with the crystal lattice of the gradual change photon crystal to excite the super prism effect of the photon crystal, and the strong space dispersion capability is realized, namely . The product of the period dx of the waveguide extension direction and the effective refractive index of the waveguide is maintained at about 0.5 according to different design parameters-0.7Between them.
According to the above ratio parameters, the invention can provide a design scheme for maintaining the effective refractive index of the waveguide at about 1.58 by changing the width of the single-mode waveguide, i.e. when the designed wavelength response range isThe periodic range of the lattice in the direction of extension of the waveguide should be. In addition, the size of the lattice of the photonic crystal formed by the scattering hole array perpendicular to the extending direction of the waveguide is about 1.5 times of the maximum lattice along the extending direction of the waveguide, namelyRemains unchanged within the same set of scattering hole arrays. The diameter of the scattered holes is about 0.6 times of the maximum lattice along the extending direction of the waveguide, namelyRemains unchanged within the same set of scattering hole arrays.
The final designed structure can reach 1 mu m/nm of space dispersion capacity in the wavelength range of 400nm-800nm in the space of 3 microns. The angular dispersion capacity of the primary diffraction of the grating with the period of the traditional 500nm is about 0.10 degrees/nm, and the optical path of 500 mu m is required to achieve the same effect. The size of a single scattering hole array is within 0.01mm multiplied by 0.05mm, eight scattering hole arrays can cover the wavelength range of 400nm-800nm, and the scattering hole arrays are connected in parallel by using beam splitters, and the overall size of the final optical chip is within 0.5mm multiplied by 0.3 mm.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (10)
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| CN202411456915.3A CN119309673A (en) | 2024-10-18 | 2024-10-18 | Wide-spectrum integrated spectrometer based on gradient photonic crystal dispersion |
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| CN202411456915.3A CN119309673A (en) | 2024-10-18 | 2024-10-18 | Wide-spectrum integrated spectrometer based on gradient photonic crystal dispersion |
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