WO2016197376A1 - 一种光栅耦合器及制备方法 - Google Patents

一种光栅耦合器及制备方法 Download PDF

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Publication number
WO2016197376A1
WO2016197376A1 PCT/CN2015/081270 CN2015081270W WO2016197376A1 WO 2016197376 A1 WO2016197376 A1 WO 2016197376A1 CN 2015081270 W CN2015081270 W CN 2015081270W WO 2016197376 A1 WO2016197376 A1 WO 2016197376A1
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Prior art keywords
waveguide
polarization
waveguides
chain
grating coupler
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PCT/CN2015/081270
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English (en)
French (fr)
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李明
涂鑫
付红岩
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华为技术有限公司
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Priority to EP15894646.7A priority Critical patent/EP3296782B1/en
Priority to PCT/CN2015/081270 priority patent/WO2016197376A1/zh
Priority to CN201580055453.7A priority patent/CN107076932B/zh
Publication of WO2016197376A1 publication Critical patent/WO2016197376A1/zh
Priority to US15/835,748 priority patent/US10317584B2/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/12004—Combinations of two or more optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/124—Geodesic lenses or integrated gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/30—Optical coupling means for use between fibre and thin-film device
    • G02B6/305—Optical coupling means for use between fibre and thin-film device and having an integrated mode-size expanding section, e.g. tapered waveguide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/34—Optical coupling means utilising prism or grating
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4206—Optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12035—Materials
    • G02B2006/12061—Silicon
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12083—Constructional arrangements
    • G02B2006/12107—Grating

Definitions

  • the present invention relates to the field of optical communication technologies, and in particular, to a grating coupler and a method for fabricating the same.
  • the Photonic Integrated Circuit (PIC) chip is fabricated on a silicon layer on an insulating substrate by using a communication device such as a laser, a modulator, and a detector prepared on different material substrates (Silicon On Insulator, SOI).
  • a communication device such as a laser, a modulator, and a detector prepared on different material substrates (Silicon On Insulator, SOI).
  • SOI Silicon On Insulator
  • the combination of silicon-based photonics and optical communication technology is an important technology to further promote global informationization.
  • the silicon-based PIC chip can input or output an optical signal by coupling to perform optical signal interaction with an external device.
  • a commonly used coupling method is that the grating coupler uses the top surface or the bottom surface of the silicon-based PIC chip as an incident surface, and externally inputs an external optical signal into the silicon-based PIC chip by diffraction, or internally the silicon-based PIC chip.
  • the optical signal is output to the outside of the silicon-based PIC
  • the bandwidth of the grating coupler characterizes the spectral range of the optical signal that can be coupled by the grating coupler.
  • the larger the bandwidth the larger the spectral range of the optical signal that can be coupled, and the greater the amount of information that can be transmitted. .
  • the bandwidth of conventional grating couplers in the prior art tends to be small.
  • a top view of a conventional grating coupler in the prior art can be seen in FIG. 1, and a normalized transmission spectrum can be seen in FIG.
  • the normalized transmission spectrum shows the correspondence between the transmission energy of the grating coupler and the wavelength of the optical signal, which indicates the correspondence between the coupling efficiency of the grating coupler and the wavelength of the optical signal.
  • the wavelength of the energy loss in the normalized transmission spectrum is the wavelength with the highest coupling efficiency of the grating coupler, which can be called the coupling center wavelength of the grating coupler, and the coupling of the grating coupler to the optical signal with the wavelength near the coupling center wavelength The higher the efficiency.
  • the coupling center wavelength of the conventional grating coupler shown in Fig. 1 is 1550 nm
  • the wavelength range corresponding to 3 dB energy is about 30 nm
  • the spectral range of the corresponding optical signal that is, the 3 dB bandwidth is about 3.8 THz, so it is difficult to satisfy the width.
  • the requirements of spectral optical communication is the wavelength with the highest coupling efficiency of the grating coupler.
  • the embodiment of the invention provides a grating coupler and a preparation method thereof, which can solve the problem of small bandwidth of the conventional grating coupler in the prior art.
  • a grating coupler comprising:
  • a substrate layer a lower confinement layer, a waveguide core layer and an upper confinement layer arranged in sequence;
  • the waveguide core layer includes a submicron waveguide, a first tapered waveguide, and a waveguide array
  • the waveguide array includes at least two waveguide groups, the waveguide group includes at least one waveguide chain, the waveguide chain includes at least two waveguides having different widths, and the waveguides in the waveguide chain are connected to each other, the same waveguide
  • the width and arrangement of the waveguides in the waveguide chain included in the group are the same, and the width and/or the arrangement of the waveguides in the waveguide chain included in the waveguide group are different;
  • one end of the waveguide chain in the waveguide array is connected to one end of the first tapered waveguide, and a narrow end of the first tapered waveguide is connected to the sub-micron waveguide.
  • adjacent two waveguides in the waveguide chain have different widths, and two adjacent waveguides on adjacent waveguide chains have different widths.
  • the waveguide array includes a first waveguide group and a second waveguide group, where the first waveguide group includes a waveguide chain, the second waveguide group comprising a second waveguide chain;
  • the first waveguide chain includes a first waveguide and a second waveguide, the first waveguide and the second waveguide being different in width and adjacent to each other;
  • the second waveguide chain includes a third waveguide and a fourth waveguide, the third waveguide and the fourth waveguide are different in width and adjacent to each other;
  • the first waveguide and the third waveguide have different widths and are adjacently arranged;
  • the second waveguide and the fourth waveguide have different widths and are adjacently arranged.
  • the waveguide in the waveguide array comprises a horizontally polarized TE Polarization-dependent waveguides and vertically polarized TM polarization-dependent waveguides;
  • the coupling efficiency of the TE polarization-dependent waveguide when transmitting an optical signal of a TE polarization mode of a specified center wavelength is greater than a first predetermined threshold; the TM polarization-related wave The coupling efficiency when transmitting the optical signal of the TM polarization mode of the specified center wavelength is greater than the first predetermined threshold.
  • the waveguide chain in the waveguide array is a TE polarization-dependent waveguide chain or a TM polarization-dependent waveguide a chain, and the TE polarization-dependent waveguide chain is arranged adjacent to the TM polarization-dependent waveguide chain;
  • the waveguides in the TE polarization-dependent waveguide chain are all TE polarization-related waveguides
  • the waveguides in the TM polarization-dependent waveguide chain are all the TM polarization-related waveguides.
  • the TE polarization-related waveguide and the TM polarization-related waveguide are adjacent to each other in the waveguide array .
  • the first waveguide and the fourth waveguide are TM polarization-related waveguides
  • the second The waveguide and the third waveguide are TE polarization dependent waveguides.
  • the waveguide in the waveguide array comprises a polarization-independent waveguide
  • the polarization-independent waveguide has a polarization-dependent loss PDL that is less than a second predetermined threshold when transmitting an optical signal of a TE polarization mode of a specified center wavelength and transmitting an optical signal of a TM polarization mode of a specified center wavelength.
  • the coupling efficiency of the polarization-independent waveguide when transmitting the optical signal of the TE polarization mode of the specified center wavelength is greater than And a third preset threshold, and a coupling efficiency when transmitting the optical signal of the TM polarization mode of the specified center wavelength is greater than the third preset threshold.
  • the waveguides in the waveguide array are all polarization independent waveguides.
  • a second tapered waveguide for connecting the waveguides having different widths in the waveguide chain.
  • the waveguide chains are arranged in parallel;
  • the waveguide chains are arranged at an angle to form a fan-ring waveguide array.
  • the waveguide in the waveguide array is a strip waveguide , ridge waveguide or slot waveguide.
  • a method of fabricating a grating coupler including:
  • the waveguide array includes at least two waveguide groups, the waveguide group including At least one waveguide chain, the waveguide chain comprising at least two waveguides having different widths, the waveguides in the waveguide chain being connected to each other, and the waveguides included in the same waveguide group have the same width and arrangement structure in the waveguide chain, Different widths and/or arrangements of waveguides in the waveguide chain included in different waveguide groups are different;
  • one end of the waveguide chain in the waveguide array is connected to one end of the first tapered waveguide, and a narrow end of the first tapered waveguide is connected to the sub-micron waveguide;
  • an upper confinement layer is prepared.
  • the preparing the waveguide core layer comprises:
  • the width and the arrangement are the same, and the width and/or the arrangement of the waveguides in the waveguide chain included in the waveguide group are different;
  • the adjacent two waveguides in the waveguide chain have different widths and are located in adjacent waveguide chains.
  • the width of the two adjacent waveguides is different.
  • the waveguide in the waveguide array comprises a horizontally polarized TE Polarization-dependent waveguides and vertically polarized TM polarization-dependent waveguides;
  • the TE polarization-dependent waveguide has a coupling efficiency greater than a first predetermined threshold when transmitting an optical signal of a TE polarization mode of a specified center wavelength; and the TM polarization-dependent waveguide transmits a light of a TM polarization mode of a specified center wavelength
  • the coupling efficiency at the time of the signal is greater than the first predetermined threshold.
  • the waveguide in the waveguide array comprises a polarization-independent waveguide
  • the polarization-independent waveguide has a polarization-dependent loss PDL that is less than a second predetermined threshold when transmitting an optical signal of a TE polarization mode of a specified center wavelength and transmitting an optical signal of a TM polarization mode of a specified center wavelength.
  • the coupling efficiency of the polarization-independent waveguide is greater than that of transmitting a TE signal of a specified central wavelength in a polarization mode And a third preset threshold, and a coupling efficiency when transmitting the optical signal of the TM polarization mode of the specified center wavelength is greater than the third preset threshold.
  • the waveguides having different widths in the waveguide chain are connected by the second tapered waveguide.
  • Embodiments of the present invention provide a grating coupler and a method for fabricating the same, comprising at least two waveguide groups in a waveguide array of a grating coupler waveguide core layer, each waveguide group including at least one waveguide chain, each waveguide chain including at least two Waveguides of different widths, such that the grating coupler can include a plurality of waveguides of different widths, can correspond to a plurality of different effective refractive indices, thereby generating a plurality of coupling center wavelengths and a normalized transmission spectrum.
  • the total normalized transmission spectrum of the grating coupler is a superposition of the sub-normalized transmission spectra of a plurality of waveguides of different widths, compared to the normalized transmission spectrum of a conventional grating coupler that typically includes only one width of the waveguide.
  • Ratio provided by the embodiment of the present invention
  • the grating coupler can significantly increase the bandwidth, thereby solving the problem of the small bandwidth of the conventional grating coupler in the prior art.
  • FIG. 1 is a top plan view of a conventional grating coupler in the prior art
  • FIG. 3 is a schematic diagram of coupling optical signals in an optical fiber through a grating coupler according to an embodiment of the present invention
  • FIG. 4 is a top plan view of a grating coupler waveguide core layer according to an embodiment of the present invention.
  • FIG. 5 is a top plan view of another grating coupler waveguide core layer according to an embodiment of the present invention.
  • FIG. 6 is a normalized transmission spectrum of a grating coupler according to an embodiment of the present invention.
  • FIG. 7 is a schematic diagram of a coupling effect of a grating coupler on an optical signal according to an embodiment of the present invention.
  • FIG. 8 is a top plan view of still another grating coupler waveguide core layer according to an embodiment of the present invention.
  • FIG. 9 is a top plan view of another grating coupler waveguide core layer according to an embodiment of the present invention.
  • FIG. 10 is a top plan view of still another grating coupler waveguide core layer according to an embodiment of the present invention.
  • FIG. 11 is a top plan view of still another grating coupler waveguide core layer according to an embodiment of the present invention.
  • FIG. 12 is a schematic diagram of a mode field distribution of a polarization-independent symmetric waveguide pair TE and TM polarization modes according to an embodiment of the present invention
  • FIG. 13 is a schematic diagram of a mode field distribution of a polarization-independent slot waveguide pair TE and TM polarization modes according to an embodiment of the present invention
  • FIG. 14 is a top plan view of another grating coupler waveguide core layer according to an embodiment of the present invention.
  • FIG. 15 is a top plan view of still another grating coupler waveguide core layer according to an embodiment of the present invention.
  • 16 is a flowchart of a method for fabricating a grating coupler according to an embodiment of the present invention
  • FIG. 17 is a flowchart of a method for preparing a waveguide core layer of a grating coupler according to an embodiment of the present invention.
  • the grating coupler mainly uses an optical device that couples light signals by diffraction and diffraction characteristics composed of a plurality of waveguide arrangements, thereby satisfying the basic grating equation: n eff represents the effective refractive index of the waveguide in the grating, characterizing the phase velocity of the optical signal that can be transmitted in the waveguide.
  • the parameters (such as width) of the waveguide are different, and the corresponding effective refractive index is different; since the conventional grating usually includes a width
  • ⁇ generally represents the coupling center wavelength of the waveguide in the grating, ie the wavelength with the highest coupling efficiency in the normalized transmission spectrum of the waveguide; k 0 represents the wave vector in vacuum; n c represents the waveguide cladding refractive index; ⁇ represents The angle of incidence of the light signal. That is to say, the effective refractive index of the waveguide in the grating coupler and the coupling center wavelength of the waveguide have the above corresponding relationship.
  • the optical signal may include a Transverse Electric (TE) polarization mode and a Vertical Polarization (TM) polarization mode, and the optical signals of different polarization modes are different due to different characteristics, boundary conditions, and the like.
  • the effective refractive index of the waveguide when transmitting optical signals of different polarization modes is also different. That is to say, in different polarization modes, the width of the waveguide has a different correspondence with the effective refractive index.
  • the coupling center wavelength of the grating coupler is related to the width of the waveguide in the grating and the polarization mode of the optical signal.
  • the grating coupler because the main function of the grating coupler is to couple the optical signal to be coupled from one optical device to another optical device, and the higher the coupling efficiency of the grating coupler to the optical signal with the central wavelength near the coupling center wavelength, the grating coupler The coupling center wavelength should be as close as possible to the center wavelength of the optical signal to be coupled, so that the grating coupler has a higher coupling efficiency for the coupled optical signal.
  • An embodiment of the present invention provides a grating coupler, which may include:
  • the waveguide core layer may comprise a submicron waveguide, a first conical waveguide and a waveguide array;
  • the waveguide array may comprise at least two waveguide groups, the waveguide group comprising at least a waveguide chain, the waveguide chain may comprise at least two waveguides of different widths, the waveguides in the waveguide chain are connected to each other, the waveguides included in the same waveguide group have the same width and arrangement structure, and the waveguides included in the different waveguide groups are waveguides.
  • the width and / or arrangement is different. Wherein one end of the waveguide chain in the waveguide array is connected to one end of the first tapered waveguide, and the narrow end of the first tapered waveguide is connected to the sub-micron waveguide.
  • the refractive index of the material used for the lower confinement layer and the material used for the upper confinement layer is smaller than the refractive index of the material used for the waveguide core layer, and thus can satisfy the total reflection condition, so that the optical signal diffracted into the grating coupler is confined between the upper confinement layer and the lower confinement layer due to total reflection, thereby passing through the waveguide core The layer is transmitted.
  • the waveguide core and substrate layers are typically silicon materials
  • the upper confinement layer and the lower confinement layer are typically silicon dioxide materials
  • the upper confinement layer is typically a transparent material.
  • the specific materials used in each part of the grating coupler are not limited in the embodiment of the present invention.
  • the waveguide array forms a grating
  • the waveguides in the waveguide array may be arranged periodically or pseudo-periodically, and the formed grating may be a uniform grating or a non-uniform grating, which is not limited herein.
  • the first tapered waveguide for connecting the waveguide array and the sub-micron waveguide can reduce the energy loss when the optical signal is converted from the grating region formed by the waveguide array to the sub-micrometer waveguide region.
  • One end of the sub-micron waveguide not connected to the first tapered waveguide is connected to the optical device, thereby inputting an optical signal external to the input chip to the optical device through a grating coupler on the chip, or outputting an optical signal in the optical device to the optical device external.
  • each waveguide group may include at least one waveguide chain
  • each of the waveguide chains may include at least two waveguides having different widths
  • the width of the waveguide in the waveguide chain included in the same waveguide group The arrangement structure is the same, and the waveguides included in the different waveguide groups have different widths and/or arrangement structures of the waveguides, and thus the grating coupler may include a plurality of waveguides having different widths.
  • the plurality of waveguides having different widths can correspond to a plurality of different effective refractive indices, thereby generating a plurality of coupling center wavelengths and sub-normalization corresponding to the plurality of coupling center wavelengths.
  • Transmission spectrum. Therefore, the total normalized transmission spectrum of the grating coupler is a superposition of sub-normalized transmission spectra of different coupling center wavelengths produced by a plurality of waveguides of different widths.
  • the 3dB wavelength range in the total normalized transmission spectrum of the grating coupler provided by the embodiment of the present invention is compared with the normalized transmission spectrum of a conventional grating coupler which generally includes only one width of the waveguide (for example, as shown in FIG. 1). Significantly increased, thereby effectively increasing the bandwidth of the grating coupler, thereby increasing the amount of information of the optical signal that can be transmitted.
  • FIG. 3 a schematic diagram of coupling an optical signal in an optical fiber through a grating coupler is provided.
  • the grating coupler is a substrate layer 0, a lower confinement layer 1, a waveguide core layer 2, and an upper confinement layer 3 from the bottom layer to the top layer.
  • Optical fiber 11 carrying optical signal Usually located above the confinement layer on the grating coupler, corresponding to the upper side of the waveguide array in the waveguide core layer, and near the end of the waveguide array not connected to the first conical waveguide, the axis of the optical fiber and the normal to the plane of the grating coupler 12
  • the resulting angle 13 is typically 5-15°.
  • the optical signal in the fiber passes through the transparent upper confinement layer in the grating coupler to the surface of the waveguide core layer, thereby being coupled into the grating coupler through the waveguide array in the waveguide core layer.
  • the carrier for the optical signal to be coupled is not limited. For example, it may be a fiber bundle, an optical waveguide, or the like.
  • the waveguide core layer may include a sub-micron waveguide 4, a first tapered waveguide 5, and a waveguide array 6.
  • the waveguide array 6 may include a first waveguide group 71 and a second waveguide group 72.
  • the first waveguide group 71 includes a first waveguide chain 81 and the second waveguide group 72 includes a second waveguide chain 82.
  • the first waveguide chain 81 includes a first waveguide 91 and a second waveguide 92 having different widths
  • the second waveguide chain 82 includes a third waveguide 93 and a fourth waveguide 94 having different widths.
  • first waveguide group 71 may further include a third waveguide chain 83 and a fifth waveguide chain 85 having the same width and arrangement structure as the waveguides in the first waveguide chain 81;
  • the second waveguide group 72 may further include a second waveguide chain The fourth waveguide chain 84 and the sixth waveguide chain 86 having the same width and arrangement of the waveguides in the 82.
  • the widths of adjacent two waveguides in the waveguide chain may be different, and the widths of two adjacent waveguides located on adjacent waveguide chains are different.
  • the waveguides of different widths in the waveguide array can be staggered, so that the area of the waveguide core layer can be utilized as much as possible, the area waste is reduced, the structure is more compact, the number of waveguides is increased, and the waveguide is in the waveguide core layer.
  • the distribution rate increases the coupling efficiency of the grating coupler.
  • a top view of the grating coupler waveguide core layer in which the waveguides having different widths are staggered can be seen in FIG. 5.
  • the first waveguide 91 and the second waveguide 92 have different widths and are adjacently arranged;
  • the second waveguide chain 82 includes a third waveguide 93 and a fourth waveguide 94, and the third waveguide 93 and the fourth waveguide 94 have different widths and adjacent
  • the first waveguide 91 and the third waveguide 93 have different widths and are adjacently arranged;
  • the second waveguide 92 and the fourth waveguide 94 have different widths and are adjacently arranged.
  • first waveguide group 71 may further include a third waveguide chain having the same width and arrangement as the waveguide in the first waveguide chain 81. 83.
  • the second waveguide group 72 may further include a fourth waveguide chain 84, which is the same as the width and arrangement structure of the waveguides in the second waveguide chain 82.
  • the width of the wide waveguide (the second waveguide and the third waveguide) in the waveguide array may be 0.2-1 ⁇ m
  • the width of the narrow waveguide (the first waveguide and the fourth waveguide) may be 0.01-0.2 ⁇ m, in the waveguide chain
  • the length of one period here, the length of a first waveguide connected to a second waveguide in the horizontal direction, or the length of a third waveguide connected to a fourth waveguide in the horizontal direction
  • the specific parameters of each part of the grating coupler can be set as needed, and the specific range is not limited herein.
  • the coupling efficiency of the grating coupler to the optical signal is higher as the center wavelength of the optical signal is closer to the coupling center wavelength, in order to make the coupling efficiency of the grating coupler to be coupled to the optical signal higher, it is necessary to make the coupling center wavelength of the grating coupler Near the center wavelength of the optical signal to be coupled.
  • the total normalized transmission spectrum of the grating coupler is a superposition of the sub-normalized transmission spectra corresponding to different coupling center wavelengths of the waveguides of different widths
  • the superposition principle of the normalized transmission spectrum can be
  • the normalized transmission spectrum of the grating coupler is decomposed into a superposition of a plurality of sub-normalized transmission spectra, and the coupling center wavelengths corresponding to the plurality of sub-normalized transmission spectra are respectively set to a specified central wavelength, so that a plurality of waveguides having different widths are obtained.
  • Corresponding coupling center wavelengths are respectively located near a plurality of designated center wavelengths, so that the coupling center wavelengths corresponding to the total normalized transmission spectra of the plurality of different width normalized transmission spectra are superposed on the optical signals to be coupled Near the center wavelength, so that the grating coupler has a higher coupling efficiency for the coupled optical signal.
  • a waveguide having a center wavelength near a specified center wavelength has a high coupling efficiency when transmitting an optical signal of the specified center wavelength.
  • the coupling center wavelengths of the waveguides of different widths are respectively near a plurality of different designated center wavelengths, the coupling efficiency when transmitting the corresponding optical signal of the specified center wavelength is high.
  • the coupling center wavelength is near the specified center wavelength, and the difference between the coupling center wavelength and the designated center wavelength is small, and the difference can be set according to actual needs.
  • the waveguides of different widths have different coupling efficiencies when transmitting optical signals of different polarization modes of a specified center wavelength.
  • the distribution of the waveguides in the grating coupler waveguide array may include The following situations:
  • the waveguides in the waveguide array are all TE polarization dependent waveguides or both are TM polarization dependent waveguides.
  • the waveguide When the waveguide has a high coupling efficiency when transmitting an optical signal of a TE polarization mode of a specified center wavelength, for example, greater than a first predetermined threshold, it may be referred to as a TE polarization-dependent waveguide.
  • the first preset threshold is usually larger (for example, 85%), and may be set according to actual needs, which is not limited herein. Since the coupling efficiency of the waveguide of the same width is different when transmitting the optical signals of different polarization modes of the specified center wavelength, the coupling efficiency of the TE polarization-dependent waveguide when transmitting the optical signal of the TM polarization mode of the specified center wavelength may be high or possible.
  • the lower, ie, polarization-dependent waveguide does not guarantee a high coupling efficiency when transmitting a TM polarization-dependent optical signal of a specified center wavelength.
  • the waveguide has a high coupling efficiency when transmitting an optical signal of a TM polarization mode of a specified center wavelength, for example, greater than a first predetermined threshold, it may be referred to as a TM polarization-dependent waveguide, and the TM polarization-dependent waveguide cannot guarantee transmission.
  • a high coupling efficiency is obtained when a TE polarization-related optical signal of a central wavelength is specified.
  • the coupling efficiency of the TE polarization-dependent waveguides of different widths is higher when transmitting the corresponding TE-polarization mode optical signals of the specified center wavelength, and different widths.
  • the coupling center wavelength of the waveguide is respectively near the specified center wavelength, thus making the coupled normalized wavelength of the grating coupler to be coupled to the optical signal in a total normalized transmission spectrum after superimposing the transmission spectra of the plurality of waveguides Near the center wavelength, the coupling efficiency of the grating coupler when transmitting the TE polarization mode to be coupled is high.
  • the grating coupler can be referred to as a TE polarization dependent grating coupler.
  • the grating coupler may be referred to as a TM polarization dependent grating coupler.
  • the TM polarization-dependent grating coupler has a high coupling efficiency when transmitting the optical signal to be coupled in the TM polarization mode.
  • the total normalized transmission spectrum of the grating coupler is a plurality of waveguides having different widths. Sub-normalized transmission spectra are superimposed to increase the bandwidth of the grating coupler.
  • the waveguides in the waveguide array may all be TE polarization dependent waveguides.
  • the thickness of the waveguide core layer may be 0.2-0.4 ⁇ m
  • the width of the sub-micron waveguide may be 0.4-0.6 ⁇ m
  • the width of the wide end of the first tapered waveguide connected thereto may be 20-40 ⁇ m
  • the length of the waveguide array It may be 20-40 ⁇ m
  • the width of the waveguide array may be 20-30 ⁇ m.
  • the waveguide chain may include a wide waveguide and a narrow waveguide in one period, the wide waveguide may have a width of 200-700 nm, and the narrow waveguide may have a width of 250 nm or less, but the wide waveguide in the first waveguide group 71 is the second waveguide 92.
  • the specific width value of the wide waveguide in the second waveguide group 72, that is, the third waveguide 93 may be different, and the narrow waveguide in the first waveguide group 71, that is, the narrow waveguide in the first waveguide 91 and the second waveguide group 72, that is, the fourth waveguide
  • the specific width values of 94 can be different, such that the waveguide array can include four different width waveguides corresponding to four different effective refractive indices, resulting in four coupled center wavelengths and a normalized transmission spectrum.
  • the specified center wavelengths may be set to 1520 nm, 1540 nm, 1560, and 1580, respectively.
  • Two waveguides of different widths in the first waveguide group 71 transmit light of the TE polarization mode.
  • the coupling center wavelengths of the signals can be 1520 nm and 1540 nm, respectively.
  • the two waveguides have the highest coupling efficiency when transmitting the TE polarization mode optical signals with the specified center wavelengths of 1520 nm and 1540 nm, respectively, and the two coupled center wavelengths respectively correspond to the sub-wavelengths.
  • the normalized transmission spectrum after normalized transmission spectrum superposition corresponds to a coupling center wavelength of 1530 nm.
  • the two waveguides of different widths in the second waveguide group 72 may have a coupling center wavelength of 1560 nm and 1580 nm when transmitting the optical signals of the TE polarization mode, respectively, and the two waveguides transmit TE polarizations having a specified center wavelength of 1560 nm and 1580 nm, respectively.
  • the coupling efficiency of the mode optical signal is the highest, and the coupled center wavelength corresponding to the normalized transmission spectrum of the two coupled center wavelengths respectively corresponding to the sub-normalized transmission spectrum is 1570 nm.
  • the supernormalized transmission spectra of the four coupling center wavelengths are superimposed to obtain a total normalized transmission spectrum of the grating coupler as shown in FIG. 6.
  • a schematic diagram of the coupling effect of the grating coupler on an optical signal having a center wavelength of 1550 nm can be seen in FIG. It should be noted that the parameter values herein are only examples, which are not limited in the embodiment of the present invention.
  • the coupling center wavelength of the grating coupler when transmitting the optical signal of the TE polarization mode is 1550 nm, which is consistent with the center wavelength of the optical signal to be coupled, and thus has the highest coupling efficiency when transmitting the TE polarization mode to be coupled optical signal.
  • the 3dB bandwidth of the total normalized transmission spectrum of the grating coupler corresponds to a wavelength range of about 100 nm, that is, the bandwidth of the TE polarization-dependent grating coupler is increased to about 12.5 THz.
  • the TE polarization-dependent grating coupler provided by the embodiment of the invention can significantly improve the bandwidth when transmitting the optical signal of the TE polarization mode of the specified center wavelength, thereby significantly improving the transmittable optical signal.
  • the amount of information can significantly improve the bandwidth when transmitting the optical signal of the TE polarization mode of the specified center wavelength, thereby significantly improving the transmittable optical signal.
  • the TM polarization-dependent grating coupler can improve the coupling efficiency and bandwidth when transmitting the optical signal of the TM polarization mode of the specified center wavelength.
  • the TE polarization-dependent grating coupler can ensure a high coupling efficiency when transmitting a TE polarization mode optical signal of a specified center wavelength, it cannot guarantee a high optical signal when transmitting a TM polarization mode of a specified center wavelength.
  • the coupling efficiency, and thus the TE polarization dependent grating coupler has a strong polarization dependence. Specifically, when a coupling center wavelength of a TE polarization-dependent grating coupler transmitting a TE polarization-related optical signal is 1550 nm, the coupling center wavelength of the waveguide when transmitting the optical signal of the TM polarization mode is 1556 nm, and Not 1550nm.
  • the coupling efficiency of the grating coupler when transmitting the optical signal of the TE polarization mode is high, and the coupling efficiency of the optical signal transmitting the TM polarization mode is low, so that the grating coupler is
  • the difference in coupling efficiency when transmitting the TE signal of the specified center wavelength and the optical signal of the TM polarization mode is large, so that the Polarization Dependent Loss (PDL) is large.
  • the PDL herein refers to the ratio of higher coupling efficiency to lower coupling efficiency when transmitting the TE polarization mode optical signal and the TM polarization mode optical signal.
  • the optical signal to be coupled is usually not a complete TE polarization mode optical signal or a complete TM polarization mode optical signal, it can be decomposed into mutually orthogonal TE polarization components.
  • the TM polarization component, and the TE/TM polarization-dependent grating coupler can only ensure the coupling efficiency of the optical signal of one of the polarization components is high, but the coupling efficiency of the other polarization component is not guaranteed, that is, The PDL is larger.
  • the total coupling efficiency of the TE/TM polarization dependent grating coupler to the optical signal is low.
  • the waveguide in the waveguide array may include a horizontally polarized TE polarization-dependent waveguide and a vertically polarized TM polarization-dependent waveguide, and the coupling efficiency of the TE polarization-related waveguide when transmitting the TE signal of the specified central wavelength in the polarization mode is greater than that of the first With a threshold, the coupling efficiency of the TM polarization-dependent waveguide when transmitting the optical signal of the TM polarization mode of the specified center wavelength is greater than the first predetermined threshold.
  • the grating coupler when the waveguides of different widths in the grating coupler waveguide array include both the TE polarization-dependent waveguide and the TM polarization-dependent waveguide, the grating coupler can simultaneously increase the TE polarization mode optical signal of the specified center wavelength. Coupling efficiency and bandwidth, as well as coupling efficiency and bandwidth when transmitting a TM polarization-dependent optical signal at a specified center wavelength. And when the optical signal includes a TE polarization component and a TM polarization component, the grating coupler can increase the total coupling efficiency and bandwidth when transmitting an optical signal of a specified center wavelength.
  • the grating coupler in Case 2 can improve the coupling bandwidth and coupling efficiency of the optical signal when transmitting the specified center wavelength, and is independent of the polarization mode, and thus can be called a polarization-independent grating coupler.
  • the number and position of the TE polarization-dependent waveguide and the TM polarization-related waveguide in the waveguide array are not specifically limited in the embodiment of the present invention.
  • the waveguides in the partial waveguide group may be TE polarization-dependent waveguides, and the waveguides in other waveguide groups may be TM polarization-dependent waveguides; or partial waves in any waveguide chain
  • the guide can be a TE polarization dependent waveguide, while the remaining waveguides can be TM polarization dependent waveguides.
  • the waveguide chain in the waveguide array is a TE polarization-dependent waveguide chain or a TM polarization-dependent waveguide chain, and the TE polarization-dependent waveguide chain is adjacent to the TM polarization-dependent waveguide chain.
  • the waveguides in the TE polarization-dependent waveguide chain are TE polarization-dependent waveguides
  • the waveguides in the TM polarization-dependent waveguide chain are all TM polarization-related waveguides.
  • a top view of a polarization-independent grating coupler waveguide core layer provided by an embodiment of the present invention can be seen in FIG. 8.
  • the waveguide array 6 includes a third waveguide group 73, a fourth waveguide group 74, a fifth waveguide group 75, and a sixth waveguide group 76.
  • Each waveguide group includes two waveguide chains, and the obliquely filled waveguide is TM polarization dependent.
  • the waveguide, the other waveguide is a TE polarization related waveguide.
  • the TE polarization dependent waveguide and the TM polarization dependent waveguide are arranged adjacent to each other in the waveguide array.
  • the TE polarization-dependent waveguide and the TM polarization-related waveguide may be adjacently arranged, and two adjacent waveguides located in adjacent waveguide chains may be TE polarization-dependent waveguides and TM polarization correlation, respectively.
  • the waveguide Exemplarily, in the waveguide array shown in FIG. 5, the first waveguide and the fourth waveguide may be TM polarization-dependent waveguides, and the second waveguide and the third waveguide may be TE polarization-related waveguides, as shown in FIG. 9 .
  • the illustrated structure of the waveguide core layer wherein the obliquely filled waveguide is a TM polarization dependent waveguide and the other waveguides are TE polarization dependent waveguides.
  • the adjacent first waveguide and the second waveguide are respectively a TM polarization-dependent waveguide and a TE polarization-related waveguide;
  • the adjacent third waveguide and the second waveguide are respectively a TE polarization-dependent waveguide and a TM polarization-related waveguide;
  • the first waveguide in the first waveguide chain is adjacent to the third waveguide in the second waveguide chain and is respectively a TM polarization-dependent waveguide and a TE polarization-dependent waveguide a waveguide;
  • the optical signal can usually be decomposed into the TE polarization mode and the TM polarization mode, and the spot of the optical signal is small when coupled by the grating coupler, the area corresponding to the grating coupler is small, when the TE polarization related waveguide and the TM polarization are When the associated waveguides are adjacently arranged, the grating coupler can simultaneously include a plurality of TE polarization-related waveguides and TM polarization-related waveguides in the corresponding spot region, so that the TE polarization component in the optical signal can be correlated by multiple TE polarizations.
  • the waveguide is coupled into the grating coupler, and the TM polarization component can be phased with the TE polarization
  • a plurality of TM polarization-dependent waveguides adjacent to the waveguide are coupled into the grating coupler, so that the coupling efficiency of the grating coupler to the optical signal can be improved.
  • the waveguide in the waveguide array includes a polarization-independent waveguide, and the polarization-dependent waveguide transmits the optical signal of the TE polarization mode at a specified center wavelength and the polarization-dependent loss when transmitting the optical signal of the TM polarization mode at a specified center wavelength is smaller than the second preset. Threshold.
  • the second preset threshold is usually small (for example, 0.1 dB), and may be set according to actual conditions, which is not limited herein.
  • the PDL is smaller than the second preset threshold, that is, the PDL is small, so that the polarization-independent waveguide has similar coupling efficiency when transmitting the optical signal of the TE polarization mode of the specified center wavelength and transmitting the optical signal of the TM polarization mode of the specified center wavelength, that is, The polarization mode has little effect on the coupling efficiency of the polarization-independent waveguide.
  • the coupling efficiency of the polarization-independent waveguide when transmitting the optical signal of the TE polarization mode of the specified center wavelength may be greater than a third preset threshold, and the coupling efficiency when transmitting the optical signal of the TM polarization mode of the specified center wavelength may be greater than The third preset threshold.
  • the third preset threshold here is also large (eg, may be 80%), but may generally be less than the first predetermined threshold. That is to say, the polarization-independent waveguide can ensure high coupling efficiency when transmitting the optical signal of the TE polarization mode of the specified center wavelength, and also has high coupling when transmitting the optical signal of the TM polarization mode of the specified center wavelength. effectiveness.
  • the polarization-independent waveguide can have a higher coupling efficiency for both polarization components.
  • the coupling efficiency at the time of transmitting the optical signal can be improved, regardless of the polarization mode of the optical signal, and thus can also be a polarization-independent grating coupler.
  • the waveguide of any width transmits the optical signal of the TE polarization mode
  • a coupling center wavelength and a sub-normalized transmission spectrum corresponding to the TE polarization mode can be generated; meanwhile, when transmitting the optical signal of the TM polarization mode, It is also possible to generate a coupled center wavelength and a sub-normalized transmission spectrum corresponding to the TM polarization mode.
  • the normalized transmission spectrum of the TE polarization mode corresponding to the grating coupler is a superposition of the sub-normalized transmission spectra generated by the plurality of polarization-independent waveguides having different widths; meanwhile, the grating coupler corresponds to the TM polarization mode
  • the normalized transmission spectrum is also a superposition of the sub-normalized transmission spectra produced by a plurality of polarization-independent waveguides of different widths. Therefore, no The grating coupler provided by the embodiment of the invention can increase the coupling bandwidth of the optical signal, thereby improving the information amount of the optical signal that can be transmitted.
  • the grating coupler provided in Case 3 can improve the coupling bandwidth and coupling efficiency of the optical signal, and is not limited by the polarization mode of the optical signal, and thus can also be called a polarization-independent grating coupler.
  • FIG. 10 a top view of a polarization-independent grating coupler provided by an embodiment of the present invention can be seen in FIG. 10.
  • the grid-filled slot waveguide is a polarization-independent waveguide
  • the obliquely-filled symmetric waveguide is a TM polarization-dependent waveguide.
  • the other waveguides are TE polarization dependent waveguides.
  • waveguides other than polarization-independent waveguides may also be TE polarization-dependent waveguides, or both are TM polarization-dependent waveguides.
  • the number and position of the polarization-independent waveguides in the grating coupler are not limited in the embodiment of the present invention.
  • the waveguides in the waveguide array may also be polarization-independent waveguides.
  • any waveguide in the waveguide array can make the coupling efficiency of the optical signals of the TE polarization mode and the TM polarization mode higher, thereby improving the waveguide.
  • the coupling efficiency of the optical signal may also be polarization-independent waveguides.
  • a top view of a polarization-independent grating coupler waveguide core layer provided by an embodiment of the present invention can be seen in FIG. 11.
  • the grid-filled slot waveguide and the grid-filled symmetric waveguide are both polarization-independent waveguides.
  • the waveguide core layer may have a thickness of 220 nm, and the waveguide array may include two waveguide groups, and any one of the waveguide chains may include two waveguides having different widths in one cycle.
  • the wide waveguide can be a polarization-independent slot waveguide, and the narrow waveguide can be a polarization-independent symmetric waveguide.
  • the width of the narrow waveguide can be around 220 nm, and the effective refractive index of such a narrow waveguide in the TE polarization mode is similar to the effective refractive index in the TM polarization mode, so that the two refractive indices respectively correspond to the TE and TM polarization modes.
  • the difference between the coupling center wavelengths is within a preset threshold.
  • the exemplary mode field distribution of the polarization-independent symmetric waveguide and the TM polarization mode in the width range can be seen in FIG.
  • the width of the slit waveguide can be In the vicinity of 400 nm, the width of the slit can be around 100 nm, and the effective refractive index in the TE polarization mode corresponding to the slit waveguide is similar to the effective refractive index in the TM polarization mode, so that the corresponding TE/TM polarization mode can be respectively made.
  • the difference in the coupled center wavelength is within a preset threshold.
  • the waveguide array may further include a second tapered waveguide for connecting waveguides having different widths in the waveguide chain, thereby being capable of reducing The energy loss when an optical signal is converted from one waveguide to another waveguide of a different width for transmission.
  • a top view of the waveguide core layer including the second tapered waveguide 10 can be seen in FIG.
  • the waveguide chains in the waveguide array may be arranged in parallel; or the waveguide chains may be arranged at an angle to form a fan-ring waveguide array.
  • the waveguide chains are arranged at an angle to form a fan-ring waveguide array and then connected to the first tapered waveguide, the length of the first tapered waveguide can be reduced, thereby saving the area occupied by the first tapered waveguide.
  • a top view of a waveguide core layer of a grating coupler having a fan-ring waveguide array can be seen in FIG.
  • the fan-ring waveguide array may have a length of 10-15 ⁇ m and a radius of 10-30 ⁇ m.
  • the waveguide array may also include more than two waveguide groups.
  • the waveguide array shown in FIG. 8 includes four waveguide groups; and any one of the waveguide chains may include more than two waveguides.
  • the embodiments of the present invention are not limited.
  • the waveguide in the waveguide array may be a strip waveguide, a ridge waveguide or a slit waveguide or other type of waveguide, which is not limited herein.
  • the submicron waveguides in the grating coupler described above may also be strip waveguides, ridge waveguides or slot waveguides or other types of waveguides.
  • a side of the substrate layer not in contact with the lower confinement layer may further have a distributed Bragg Reflection (DBR) or a metal reflective layer to improve the optical signal inside the grating coupler at the substrate layer.
  • DBR distributed Bragg Reflection
  • the reflectivity prevents the optical signal from leaking out of the substrate layer to the grating coupler, thereby improving the coupling efficiency of the grating coupler.
  • the incident surface of the optical signal may be covered with a polysilicon layer to reduce signal reflection of the external light signal on the incident surface of the grating coupler, thereby improving the optical signal that can be diffracted into the grating coupler. Improve the coupling efficiency of the grating coupler.
  • the refractive index matching liquid or other related art in the prior art can be combined to improve the coupling efficiency of the grating coupler, which is not limited in the embodiment of the present invention.
  • parameter values of the components in the grating coupler according to the embodiment of the present invention are only exemplified, and may be set according to actual conditions, which is not limited by the embodiment of the present invention.
  • Embodiments of the present invention provide a grating coupler including at least two waveguide groups in a waveguide array of a grating coupler waveguide core layer, each waveguide group including at least one waveguide chain, each waveguide chain including at least two different widths
  • the waveguide, such that the grating coupler can include a plurality of waveguides of different widths, can correspond to a plurality of different effective refractive indices, thereby generating a plurality of coupled center wavelengths and a normalized transmission spectrum.
  • the total normalized transmission spectrum of the grating coupler is a superposition of the sub-normalized transmission spectra of a plurality of waveguides of different widths, compared to the normalized transmission spectrum of a conventional grating coupler that typically includes only one width of the waveguide.
  • the grating coupler provided by the embodiment of the invention can significantly increase the bandwidth, thereby solving the problem that the bandwidth of the conventional grating coupler is small in the prior art.
  • An embodiment of the present invention provides a method for fabricating a grating coupler. Referring to FIG. 16, the main steps may include:
  • a lower confinement layer is prepared.
  • the waveguide core layer comprises a submicron waveguide, a first tapered waveguide and a waveguide array;
  • the waveguide array comprises at least two waveguide groups, the waveguide group comprises at least one waveguide chain, the waveguide chain comprises at least two waveguides of different widths, and the waveguide in the waveguide chain Connected to each other, the width and arrangement of the waveguides in the waveguide chain included in the same waveguide group are the same, and the width and/or the arrangement of the waveguides in the waveguide chains included in different waveguide groups are different.
  • one end of the waveguide chain in the waveguide array is connected to one end of the first tapered waveguide, and the narrow end of the first tapered waveguide is connected to the sub-micron waveguide.
  • an upper confinement layer is prepared.
  • each waveguide group may include at least one waveguide chain, and each waveguide chain At least two waveguides having different widths may be included, and the width and arrangement of the waveguides in the waveguide chain included in the same waveguide group are the same, and the width and/or arrangement of the waveguides in the waveguide chain included in different waveguide groups are different, and thus the grating coupler is A plurality of waveguides having different widths may be included.
  • the plurality of waveguides having different widths may correspond to a plurality of different effective refractive indices, thereby generating a plurality of coupling center wavelengths and a plurality of coupling center wavelengths corresponding to each other.
  • Transmission spectrum. Therefore, the total normalized transmission spectrum of the grating coupler is a superposition of sub-normalized transmission spectra corresponding to different coupling center wavelengths produced by a plurality of waveguides having different widths.
  • the 3dB wavelength range in the total normalized transmission spectrum of the grating coupler provided by the embodiment of the present invention is compared with the normalized transmission spectrum of a conventional grating coupler which generally includes only one width of the waveguide (for example, as shown in FIG. 1). Significantly increased, thereby effectively increasing the bandwidth of the grating coupler, thereby increasing the amount of information of the optical signal that can be transmitted.
  • the preparation of the waveguide core layer in step 103 may specifically include steps 201-204:
  • the optical signal to be coupled is usually a central wavelength optical signal commonly used in communication, for example, 1550 nm.
  • the specified central wavelength may be first set according to the central wavelength of the optical signal to be coupled.
  • the specified center wavelength is usually near the center wavelength of the optical signal to be coupled.
  • the coupling center wavelength of the waveguide is near a predetermined specified center wavelength, the normalized transmission spectrum of the supernormalized transmission spectrum of the plurality of waveguides having different widths is superimposed.
  • the corresponding coupling center wavelength is near the center wavelength of the optical signal to be coupled, and the grating coupler has a higher coupling efficiency when transmitting the optical signal to be coupled.
  • the specified center wavelengths may be 1520 nm, 1540 nm, 1560 nm, and 1570 nm.
  • a set of widths of the waveguides such that the coupled center wavelengths are within a certain difference range from the specified center wavelength, which is typically small, are determined based on the specified center wavelength. Since the coupling efficiency is higher toward the coupling center wavelength, the coupling efficiency of the waveguide to the optical signal of the specified center wavelength is higher when the coupling center wavelength is near the specified center wavelength.
  • waveguides with different widths can be prepared, so that the grating coupler comprises a plurality of waveguides with different widths, so that the normalized transmission spectrum of the grating coupler is sub-normalized transmission of waveguides with different widths.
  • the superposition of spectra can effectively increase the bandwidth.
  • the waveguide prepared in this step may be a strip waveguide, a ridge waveguide, a slit waveguide or other type
  • the waveguide is not limited here.
  • This step may include a plurality of waveguides having different widths in the waveguide chain.
  • the waveguides having different widths may be periodically or pseudo-periodically arranged, which is not limited herein.
  • the waveguide chains Aligning the waveguide chains into a waveguide array, so that the waveguide array includes at least two waveguide groups, the waveguide group includes at least one waveguide chain, and the waveguide group includes a waveguide having the same width and arrangement structure, and different waveguide groups include waveguides.
  • the width and/or arrangement of the waveguides in the chain are different.
  • the waveguide arrays in which the waveguide chains are arranged form a grating, wherein the gratings may be uniform gratings or non-uniform gratings, and the optical signals to be coupled may be coupled by gratings and diffraction characteristics.
  • the waveguide chains in the waveguide array may be arranged in parallel or may be arranged at an angle to form a fan-ring waveguide array to reduce the length of the first tapered waveguide connected thereto, thereby saving the area occupied by the first tapered waveguide.
  • the widths of two adjacent waveguides in the waveguide chain in the waveguide array may be different, and the widths of two adjacent waveguides located on adjacent waveguide chains may be different.
  • waveguides having different widths may be staggered, thereby reducing area waste, utilizing the area of the waveguide core layer as much as possible, making the structure more compact, increasing the number of waveguides and the waveguide.
  • the distribution ratio of the core layer thereby improving the coupling efficiency of the grating coupler.
  • the foregoing step 201 may specifically include:
  • the grating equation shows the correspondence between the coupling center wavelength and the effective refractive index, and thus the set of effective refractive indices corresponding to the specified center wavelength can be determined according to the grating equation.
  • step 302 may specifically include steps 401-402 and steps 501-502.
  • TE polarization dependent waveguide 401 Determine, in a horizontally polarized TE polarization mode, a set of widths of TE polarization dependent waveguides according to a set of effective refractive indices.
  • the coupling efficiency of the TE polarization-dependent waveguide when transmitting the optical signal of the TE polarization mode of the specified center wavelength is greater than the first preset threshold.
  • a description of the TE polarization dependent waveguide can be found in the device embodiment.
  • a TE-polarization-dependent waveguide of a corresponding width can be prepared according to the width value in the width set of the TE polarization-dependent waveguide, so that the waveguide array can include multiple widths.
  • Different TE polarization-related waveguides make the normalized transmission spectrum of the grating coupler superimpose the normalized transmission spectra of multiple TE polarization-related waveguides with different widths, so that the TE polarized light signal in the preset wavelength range can be significantly improved.
  • the coupling bandwidth effectively increases the amount of information of the transmittable TE-polarized light signal.
  • step 302 can include:
  • TM polarization-dependent waveguide 501 Determine a set of widths of the TM polarization-dependent waveguides according to a set of effective refractive indices in a vertically polarized TM polarization mode.
  • the coupling efficiency of the TM polarization-dependent waveguide when transmitting the optical signal of the TM polarization mode of the specified center wavelength is greater than the first preset threshold.
  • a description of the TM polarization dependent waveguide can be found in the device embodiment.
  • a TM polarization-dependent waveguide of a corresponding width can be prepared according to the width value in the width set of the TM polarization-dependent waveguide, so that the waveguide array can include multiple widths.
  • Different TM polarization-related waveguides make the normalized transmission spectrum of the grating coupler superimpose the normalized transmission spectra of multiple TM polarization-dependent waveguides with different widths, so that the TM polarized light signal in the preset wavelength range can be significantly improved.
  • the coupling bandwidth effectively increases the amount of information of the transmittable TM polarized light signal.
  • the waveguides in the waveguide array comprise TE polarization dependent waveguides and TM polarization dependent waveguides.
  • the TE polarization-dependent waveguides having different widths obtained by the steps 401 and 402 and the TM polarization-related waveguides having different widths obtained by the steps 501 and 502 can be simultaneously included in the waveguide array, thereby improving the grating coupler.
  • the coupling bandwidth and coupling efficiency and the amount of information of the optical signal that can be transmitted can be found in the description of the device embodiment.
  • the TE polarization-related waveguide and the TM polarization-related waveguide can be arranged in the waveguide array to better improve the coupling efficiency of the grating coupler. For details, refer to the description in the device embodiment.
  • the waveguide in the waveguide array comprises a polarization-independent waveguide
  • the polarization-independent waveguide transmits an optical signal of a TE polarization mode at a specified center wavelength and a polarization-dependent loss PDL when transmitting an optical signal of a TM polarization mode of a specified center wavelength.
  • the coupling efficiency of the polarization-independent waveguide when transmitting the optical signal of the TE polarization mode of the specified center wavelength is greater than the third predetermined threshold, and the coupling efficiency when transmitting the optical signal of the TM polarization mode of the specified center wavelength is greater than the third Preset threshold.
  • the preparing the polarization-independent waveguide in step 201 may specifically include:
  • the coupling efficiency is greater than the third predetermined threshold and is greater than the third predetermined threshold when transmitting the optical signal of the TM polarization mode of the specified center wavelength.
  • the waveguide can be made
  • the array includes a plurality of polarization-independent waveguides, or the waveguides in the waveguide array may be polarization-independent waveguides, thereby improving the coupling bandwidth and coupling efficiency of the grating coupler to the optical signal, and the information amount of the optical signal that can be transmitted.
  • the waveguides in the waveguide array may be polarization-independent waveguides, thereby improving the coupling bandwidth and coupling efficiency of the grating coupler to the optical signal, and the information amount of the optical signal that can be transmitted.
  • the above step 202 may specifically include: connecting at least two waveguides having different widths through the second tapered waveguide to form a waveguide chain.
  • the second tapered waveguide for connecting the waveguides having different widths can reduce the energy loss when the optical signal is converted by one width waveguide to another waveguide having a different width.
  • the prior art such as DBR, metal reflective layer, polysilicon layer, and refractive index matching liquid may be combined to improve the coupling efficiency of the grating coupler.
  • An embodiment of the present invention provides a method for fabricating a grating coupler.
  • the waveguide array of the obtained grating coupler waveguide core layer includes at least two waveguide groups, and each waveguide group includes at least one waveguide chain, and each waveguide chain includes at least one waveguide chain.
  • the total normalized transmission spectrum of the grating coupler is a superposition of the sub-normalized transmission spectra of a plurality of waveguides of different widths, compared to the normalized transmission spectrum of a conventional grating coupler that typically includes only one width of the waveguide.
  • the grating coupler provided by the embodiment of the invention can significantly increase the bandwidth, thereby solving the problem that the bandwidth of the conventional grating coupler is small in the prior art.

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Abstract

一种光栅耦合器及其制备方法。该光栅耦合器包括：依次排列的衬底层(0)、下限制层(1)、波导芯层(2)和上限制层(3)。该波导芯层(2)包括亚微米波导(4)、第一锥形波导(5)和波导阵列(6)。该波导阵列(6)包括至少两个波导群，该波导群包括至少一条波导链，该波导链包括至少两个宽度不同的波导，该波导链中的该波导相互连接。同一该波导群的该波导链中波导的宽度和排列结构相同，不同该波导群的该波导链中波导的宽度和/或排列结构不同。该波导阵列(6)中该波导链的一端与该第一锥形波导(5)宽的一端连接，该第一锥形波导(5)窄的一端与该亚微米波导(4)连接。该光栅耦合器能提高带宽。

Description

一种光栅耦合器及制备方法 技术领域
本发明涉及光通信技术领域，尤其涉及一种光栅耦合器及制备方法。
背景技术
硅基光子集成回路(Photonic Integrated Circuit，PIC)芯片通过将制备在不同材料基片上的激光器、调制器、探测器等通信器件统一制备到绝缘衬底上的硅层上(Silicon On Insulator，SOI)，从而将硅基光子学与光通信技术相结合，是进一步推动全球信息化的重要技术。硅基PIC芯片可以通过耦合的方式输入或输出光信号，从而与外部器件进行光信号交互。其中，一种常用的耦合方式是，光栅耦合器以硅基PIC芯片的顶面或底面为入射面，通过衍射的方式将外部的光信号输入硅基PIC芯片内部，或者将硅基PIC芯片内部的光信号输出至硅基PIC芯片外部。
其中，光栅耦合器的带宽表征了可以通过光栅耦合器进行耦合的光信号的频谱范围，带宽越大则可以耦合的光信号的频谱范围就越大，可传输的光信号的信息量就越大。然而，现有技术中的传统光栅耦合器的带宽往往较小。例如，现有技术中的一种传统光栅耦合器的俯视图可以参见图1，其归一化透射谱可以参见图2。归一化透射谱表明了光栅耦合器对光信号的透射能量与光信号波长的对应关系，即表明了光栅耦合器对光信号的耦合效率与光信号波长的对应关系。其中，归一化透射谱中能量损耗最小的波长为光栅耦合器耦合效率最高的波长，可以称为光栅耦合器的耦合中心波长，且光栅耦合器对波长越靠近耦合中心波长的光信号的耦合效率越高。由图2可知，图1所示传统光栅耦合器的耦合中心波长为1550nm，3dB能量对应的波长范围约为30nm，对应的光信号的频谱范围即3dB带宽约为3.8THz，因而很难满足宽谱光通信的要求。
发明内容
本发明实施例提供一种光栅耦合器及制备方法，能够解决现有技术中传统光栅耦合器的带宽小的问题。
为达到上述目的，本发明的实施例采用如下技术方案：
第一方面，提供一种光栅耦合器，包括：
依次排列的衬底层、下限制层、波导芯层和上限制层；
所述波导芯层包括亚微米波导、第一锥形波导和波导阵列；
所述波导阵列包括至少两个波导群，所述波导群包括至少一条波导链，所述波导链包括至少两个宽度不同的波导，所述波导链中的所述波导相互连接，同一所述波导群包括的所述波导链中波导的宽度和排列结构相同，不同所述波导群包括的所述波导链中波导的宽度和/或排列结构不同；
其中，所述波导阵列中所述波导链的一端与所述第一锥形波导宽的一端连接，所述第一锥形波导窄的一端与所述亚微米波导连接。
结合第一方面，在第一方面的第一种可能的实现方式中，所述波导链中相邻两个波导的宽度不同，位于相邻波导链上的两个相邻波导的宽度不同。
结合第一方面的第一种可能的实现方式，在第一方面的第二种可能的实现方式中，所述波导阵列包括第一波导群和第二波导群，所述第一波导群包括第一波导链，所述第二波导群包括第二波导链；
所述第一波导链包括第一波导和第二波导，所述第一波导与所述第二波导的宽度不同且相邻排列；
所述第二波导链包括第三波导和第四波导，所述第三波导与所述第四波导的宽度不同且相邻排列；
所述第一波导与所述第三波导的宽度不同且相邻排列；
所述第二波导与所述第四波导的宽度不同且相邻排列。
结合第一方面至第一方面的第二种可能的实现方式中的任意一种，在第一方面的第三种可能的实现方式中，所述波导阵列中的所述波导包括水平极化TE偏振相关的波导和垂直极化TM偏振相关的波导；
其中，所述TE偏振相关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第一预设阈值；所述TM偏振相关的波 导在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第一预设阈值。
结合第一方面的第三种可能的实现方式，在第一方面的第四种可能的实现方式中，所述波导阵列中的所述波导链为TE偏振相关的波导链或TM偏振相关的波导链，且所述TE偏振相关的波导链与所述TM偏振相关的波导链相邻排列；
其中，所述TE偏振相关的波导链中的所述波导均为所述TE偏振相关的波导，所述TM偏振相关的波导链中的所述波导均为所述TM偏振相关的波导。
结合第一方面的第三种可能的实现方式，在第一方面的第五种可能的实现方式中，所述波导阵列中所述TE偏振相关的波导和所述TM偏振相关的波导相邻排列。
结合第一方面的第二种可能的实现方式，在第一方面的第六种可能实现的方式中，所述第一波导和所述第四波导为TM偏振相关的波导，且所述第二波导和所述第三波导为TE偏振相关的波导。
结合第一方面至第一方面的第二种可能的实现方式中的任意一种，在第一方面的第七种可能的实现方式中，所述波导阵列中的所述波导包括偏振无关的波导，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号和在传输指定中心波长的TM偏振模式的光信号时的偏振相关损耗PDL小于第二预设阈值。
结合第一方面的第七种可能的实现方式，在第一方面的第八种可能的实现方式中，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第三预设阈值，且在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第三预设阈值。
结合第一方面的第八种可能的实现方式，在第一方面的第九种可能的实现方式中，所述波导阵列中的所述波导均为所述偏振无关的波导。
结合第一方面至第一方面的第九种可能的实现方式中的任意一种，在第一方面的第十种可能的实现方式中，还包括：
第二锥形波导，用于连接所述波导链中宽度不同的所述波导。
结合第一方面至第一方面的第十种可能的实现方式中的任意一种，在第一方面的第十一种可能的实现方式中，所述波导链平行排列；
或者，所述波导链成一定角度排列成扇环波导阵列。
结合第一方面至第一方面的第十一种可能的实现方式中的任意一种，在第一方面的第十二种可能的实现方式中，所述波导阵列中的所述波导为条波导、脊波导或狭缝波导。
第二方面，提供一种光栅耦合器的制备方法，包括：
制备衬底层；
在所述衬底层的基础上，制备下限制层；
在所述下限制层的基础上，制备波导芯层，所述波导芯层包括亚微米波导、第一锥形波导和波导阵列；所述波导阵列包括至少两个波导群，所述波导群包括至少一条波导链，所述波导链包括至少两个宽度不同的波导，所述波导链中的所述波导相互连接，同一所述波导群包括的所述波导链中波导的宽度和排列结构相同，不同所述波导群包括的所述波导链中波导的宽度和/或排列结构不同；
其中，所述波导阵列中所述波导链的一端与所述第一锥形波导宽的一端连接，所述第一锥形波导窄的一端与所述亚微米波导连接；
在所述波导芯层的基础上，制备上限制层。
结合第二方面，在第二方面的第一种可能的实现方式中，所述制备波导芯层包括：
制备所述波导；
将宽度不同的至少两个所述波导连接形成所述波导链；
将所述波导链排列成所述波导阵列，使得所述波导阵列包括至少两个所述波导群，所述波导群包括至少一条波导链，同一所述波导群包括的所述波导链中波导的宽度和排列结构相同，不同所述波导群包括的所述波导链中波导的宽度和/或排列结构不同；
将所述波导阵列中所述波导链的一端与所述第一锥形波导宽的一端连接，将所述第一锥形波导窄的一端与所述亚微米波导连接，从而形成所述波导芯层。
结合第二方面或第二方面的第一种可能的实现方式，在第二方面的第二种可能的实现方式中，所述波导链中相邻两个波导的宽度不同，位于相邻波导链上的两个相邻波导的宽度不同。
结合第二方面至第二方面的第二种可能的实现方式中的任意一种，在第二方面的第三种可能的实现方式中，所述波导阵列中的所述波导包括水平极化TE偏振相关的波导和垂直极化TM偏振相关的波导；
其中，所述TE偏振相关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第一预设阈值；所述TM偏振相关的波导在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第一预设阈值。
结合第二方面至第二方面的第二种可能的实现方式中的任意一种，在第二方面的第四种可能的实现方式中，所述波导阵列中的所述波导包括偏振无关的波导，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号和在传输指定中心波长的TM偏振模式的光信号时的偏振相关损耗PDL小于第二预设阈值。
结合第二方面的第四种可能的实现方式，在第二方面的第五种可能的实现方式中，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第三预设阈值，且在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第三预设阈值。
结合第二方面至第二方面的第五种可能的实现方式，在第二方面的第六种可能的实现方式中，所述波导链中宽度不同的所述波导通过第二锥形波导连接。
本发明实施例提供一种光栅耦合器及制备方法，在光栅耦合器波导芯层的波导阵列中包括至少两个波导群，每个波导群包括至少一条波导链，每条波导链包括至少两个宽度不同的波导，从而使得光栅耦合器中可以包括多个宽度不同的波导，可以对应多个不同的有效折射率，从而可以产生多个耦合中心波长及归一化透射谱。因而，光栅耦合器总的归一化透射谱是多个宽度不同的波导的子归一化透射谱的叠加，与通常仅包括一种宽度的波导的传统光栅耦合器的归一化透射谱相比，本发明实施例提供的 光栅耦合器可以显著提高带宽，从而能够解决现有技术中传统光栅耦合器带宽小的问题。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为现有技术中一种传统光栅耦合器的俯视图；
图2为现有技术中传统光栅耦合器的归一化透射谱；
图3为本发明实施例提供的一种光纤中的光信号通过光栅耦合器进行耦合的示意图；
图4为本发明实施例提供的一种光栅耦合器波导芯层的俯视图；
图5为本发明实施例提供的另一种光栅耦合器波导芯层的俯视图；
图6为本发明实施例提供的一种光栅耦合器的归一化透射谱；
图7为本发明实施例提供的一种光栅耦合器对光信号的耦合效果示意图；
图8为本发明实施例提供的又一种光栅耦合器波导芯层的俯视图；
图9为本发明实施例提供的另一种光栅耦合器波导芯层的俯视图；
图10为本发明实施例提供的又一种光栅耦合器波导芯层的俯视图；
图11为本发明实施例提供的再一种光栅耦合器波导芯层的俯视图；
图12为本发明实施例提供的一种偏振无关的对称波导对TE、TM偏振模式的模场分布图；
图13为本发明实施例提供的一种偏振无关的狭缝波导对TE、TM偏振模式的模场分布图；
图14为本发明实施例提供的另一种光栅耦合器波导芯层的俯视图；
图15为本发明实施例提供的又一种光栅耦合器波导芯层的俯视图；
图16为本发明实施例提供的一种光栅耦合器的制备方法流程图；
图17为本发明实施例提供的一种制备光栅耦合器的波导芯层的方法流程图。
附图标记：
0-衬底层；1-下限制层；2-波导芯层；3-上限制层；4-亚微米波导；5-第一锥形波导；6-波导阵列；71-第一波导群；72-第二波导群；73-第三波导群；74-第四波导群；75-第五波导群；76-第六波导群；81-第一波导链；82-第二波导链；83-第三波导链；84-第四波导链；85-第五波导链；86-第六波导链；87-第七波导链；88-第八波导链；89-第九波导链；91-第一波导；92-第二波导；93-第三波导；94-第四波导；10-第二锥形波导；11-光纤；12-法线；13-光纤的轴线与法线的夹角。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
在本发明的描述中，需要理解的是，术语“上”、“下”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。
光栅耦合器主要是利用由多个波导排列组成的光栅及衍射特性进行光信号耦合的光学器件，因而满足基本的光栅方程：
Figure PCTCN2015081270-appb-000001
neff表示光栅中波导的有效折射率，表征了波导中可传输的光信号的相速度的 大小，波导的参数(例如宽度)不同，对应的有效折射率不同；由于传统光栅通常包括一种宽度的波导，因而Λ通常表示光栅中波导的耦合中心波长，即波导的归一化透射谱中耦合效率最高的波长；k0表示真空中的波矢；nc表示波导包层折射率；θ表示光信号的入射角度。也就是说，光栅耦合器中波导的有效折射率和波导的耦合中心波长存在上述对应关系。
另外，光信号可以包括水平极化(Transverse Electric，TE)偏振模式和垂直极化(Transverse Magnetic，TM)偏振模式，对于不同偏振模式的光信号，由于其特性、边界条件等因素不同，因而同一波导在传输不同偏振模式的光信号时的有效折射率也不同。也就是说，在不同偏振模式下，波导的宽度与有效折射率存在不同的对应关系。
由于波导的有效折射率与耦合中心波长存在对应关系，而光信号的不同偏振模式以及波导的不同宽度，都影响波导的有效折射率。因而，光栅耦合器的耦合中心波长与光栅中波导的宽度，以及光信号的偏振模式这两个因素有所关联。
又由于光栅耦合器的主要作用是将待耦合光信号从一个光学器件耦合进另一个光学器件，而光栅耦合器对中心波长越靠近耦合中心波长的光信号的耦合效率越高，因而光栅耦合器的耦合中心波长应尽量靠近待耦合光信号的中心波长，以使得光栅耦合器对待耦合光信号具有较高的耦合效率。
本发明实施例提供一种光栅耦合器，可以包括：
依次排列的衬底层、下限制层、波导芯层和上限制层；波导芯层可以包括亚微米波导、第一锥形波导和波导阵列；波导阵列可以包括至少两个波导群，波导群包括至少一条波导链，波导链可以包括至少两个宽度不同的波导，波导链中的波导相互连接，同一波导群包括的波导链中波导的宽度和排列结构相同，不同波导群包括的波导链中波导的宽度和/或排列结构不同。其中，波导阵列中波导链的一端与第一锥形波导宽的一端连接，第一锥形波导窄的一端与亚微米波导连接。
在光栅耦合器中，下限制层所用材料的折射率和上限制层所用材料 的折射率小于波导芯层所用材料的折射率，因而能够满足全反射条件，使得衍射进光栅耦合器的光信号由于全反射作用被限制在上限制层和下限制层之间，从而通过波导芯层进行传输。波导芯层和衬底层通常为硅材料，上限制层和下限制层通常为二氧化硅材料，上限制层通常为透明材料。当然，本发明实施例对光栅耦合器各部分所采用的具体材料并不限定。
在上述光栅耦合器的波导芯层中，波导阵列形成了光栅，波导阵列中的波导可以周期性排列也可以伪周期性排列，形成的光栅可以是均匀光栅也可以是非均匀光栅，这里不做限定。其中，用于连接波导阵列和亚微米波导的第一锥形波导可以减小光信号由波导阵列构成的光栅区域向亚微米波导区域转换时的能量损耗。亚微米波导未与第一锥形波导连接的一端连接至光学器件，从而通过芯片上的光栅耦合器将输入的芯片外部的光信号输入至光学器件，或将光学器件中的光信号输出至芯片外部。
由于波导阵列可以包括至少两个不同的波导群，每个波导群可以包括至少一条波导链，每条波导链可以包括至少两个宽度不同的波导，且同一波导群包括的波导链中波导的宽度和排列结构相同，不同波导群包括的波导链中波导的宽度和/或排列结构不同，因而光栅耦合器中可以包括多个宽度不同的波导。
又由于宽度不同的波导对应的有效折射率不同，因而多个宽度不同的波导可以对应多个不同的有效折射率，从而可以产生多个耦合中心波长以及多个耦合中心波长对应的子归一化透射谱。因此，光栅耦合器总的归一化透射谱为多个宽度不同的波导所产生的不同耦合中心波长的子归一化透射谱的叠加。与通常仅包括一种宽度的波导(例如图1所示)的传统光栅耦合器的归一化透射谱相比，本发明实施例提供的光栅耦合器总的归一化透射谱中3dB波长范围明显增大，从而有效提高了光栅耦合器的带宽，进而增大了可传输的光信号的信息量。
示例性的，参见图3，本发明实施例提供的一种光纤中的光信号通过光栅耦合器进行耦合的示意图。其中，光栅耦合器从底层至顶层依次为衬底层0、下限制层1、波导芯层2、上限制层3。承载光信号的光纤11通 常位于光栅耦合器上限制层的上方，对应于波导芯层中波导阵列的上方，且靠近波导阵列未与第一锥形波导连接的一端，光纤的轴线与光栅耦合器所在平面的法线12所成的夹角13通常为5-15°。光纤中的光信号透过光栅耦合器中透明的上限制层到达波导芯层的表面，从而通过波导芯层中的波导阵列耦合进光栅耦合器。需要说明的是，本发明实施例仅是以光纤为例进行说明，对于待耦合光信号的载体并不做限定，例如，还可以是光纤束、光波导等。
示例性的，本发明实施例提供的一种光栅耦合器波导芯层的俯视图可以参见图4。其中，波导芯层可以包括亚微米波导4、第一锥形波导5和波导阵列6。波导阵列6可以包括第一波导群71和第二波导群72。第一波导群71包括第一波导链81，第二波导群72包括第二波导链82。第一波导链81包括宽度不同的第一波导91和第二波导92，第二波导链82包括宽度不同的第三波导93和第四波导94。此外，第一波导群71还可以包括与第一波导链81中波导的宽度和排列结构相同的第三波导链83、第五波导链85；第二波导群72还可以包括与第二波导链82中波导的宽度和排列结构相同的第四波导链84、第六波导链86。
优选地，波导链中相邻两个波导的宽度可以不同，位于相邻波导链上的两个相邻波导的宽度不同。这样一来，可以使得波导阵列中不同宽度的波导能够交错排列，从而可以尽可能大地利用波导芯层的面积，减少了面积浪费，使得结构更加紧凑，增加了波导的数量及波导在波导芯层的分布率，从而提高了光栅耦合器的耦合效率。
示例性的，在图4所示结构的波导芯层的基础上，将宽度不同的波导交错排列后的光栅耦合器波导芯层的俯视图可以参见图5。其中，第一波导91与第二波导92的宽度不同且相邻排列；第二波导链82包括第三波导93和第四波导94，第三波导93与第四波导94的宽度不同且相邻排列；第一波导91与第三波导93的宽度不同且相邻排列；第二波导92与第四波导94的宽度不同且相邻排列。此外，第一波导群71还可以包括与第一波导链81中波导的宽度和排列结构相同的第三波导链 83、第五波导链85、第七波导链87和第九波导链89；第二波导群72还可以包括与第二波导链82中波导的宽度和排列结构相同的第四波导链84、第六波导链86和第八波导链88。具体的，波导阵列中的宽波导(第二波导和第三波导)的宽度可以是0.2-1μm，窄波导(第一波导和第四波导)的宽度可以是0.01-0.2μm，波导链中的一个周期的长度(这里为水平方向上一个第一波导与一个第二波导连接后的长度，或水平方向上一个第三波导与一个第四波导连接后的长度)可以是0.5-3μm。需要说明的是，光栅耦合器中各部分的具体参数可以根据需要进行设定，这里仅是举例说明，具体范围不做限定。
由于光信号的中心波长越靠近耦合中心波长时光栅耦合器对光信号的耦合效率越高，因而为了使得光栅耦合器对待耦合光信号的耦合效率较高，需要使得光栅耦合器的耦合中心波长在待耦合光信号的中心波长附近。又由于光栅耦合器总的归一化透射谱是多个宽度不同的波导分别产生的不同耦合中心波长对应的子归一化透射谱的叠加，因而可以根据归一化透射谱的叠加原理，将光栅耦合器的归一化透射谱分解为多个子归一化透射谱的叠加，并将多个子归一化透射谱分别对应的耦合中心波长设定为指定中心波长，使得多个宽度不同的波导分别对应的耦合中心波长分别在多个指定中心波长附近，从而使得多个宽度不同的子归一化透射谱叠加后的总的归一化透射谱对应的耦合中心波长可以在待耦合光信号的中心波长附近，从而使得光栅耦合器对待耦合光信号具有较高的耦合效率。其中，耦合中心波长在指定中心波长附近的波导，在传输该指定中心波长的光信号时的耦合效率较高。不同宽度的波导的耦合中心波长分别在多个不同指定中心波长附近时，在传输对应的指定中心波长的光信号时的耦合效率较高。其中，耦合中心波长在指定中心波长附近可以理解为耦合中心波长与指定中心波长的差值较小，该差值可以根据实际需要进行设定。
又由于对于任一指定中心波长来说，不同宽度的波导在传输指定中心波长的不同偏振模式的光信号时的耦合效率不同，因而，示例性的，光栅耦合器波导阵列中波导的分布可以包括以下几种情况：
情况1：
波导阵列中的波导均为TE偏振相关的波导或者均为TM偏振相关的波导。
当波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率较高，例如大于第一预设阈值时，可以称为TE偏振相关的波导。这里的第一预设阈值通常较大(例如可以为85％)，具体可以根据实际需要进行设置，这里不做限定。由于同一宽度的波导在传输指定中心波长的不同偏振模式的光信号时的耦合效率不同，因而TE偏振相关的波导在传输指定中心波长的TM偏振模式的光信号时的耦合效率可能较高也可能较低，即TE偏振相关的波导不能保证在传输指定中心波长的TM偏振相关的光信号时具有较高的耦合效率。同样，当波导在传输指定中心波长的TM偏振模式的光信号时的耦合效率较高，例如大于第一预设阈值时，可以称为TM偏振相关的波导，TM偏振相关的波导不能保证在传输指定中心波长的TE偏振相关的光信号时具有较高的耦合效率。
当光栅耦合器中的波导均为TE偏振相关的波导时，由于不同宽度的TE偏振相关的波导分别在传输对应的指定中心波长的TE偏振模式的光信号时的耦合效率较高，且不同宽度的波导的耦合中心波长分别在指定中心波长附近，因而使得多个波导的子归一化透射谱叠加后的总的归一化透射谱中，光栅耦合器的耦合中心波长在待耦合光信号的中心波长附近，因此光栅耦合器在传输TE偏振模式的待耦合光信号时的耦合效率较高。当光栅耦合器中的波导均为TE偏振相关的波导时，该光栅耦合器可以称为TE偏振相关的光栅耦合器。
与光栅耦合器中的波导均为TE偏振相关波导的情况类似，当光栅耦合器中的波导均为TM偏振相关的波导时，该光栅耦合器可以称为TM偏振相关的光栅耦合器。TM偏振相关的光栅耦合器在传输TM偏振模式的待耦合光信号时的耦合效率较高。
同时，由于上述TE/TM偏振相关的光栅耦合器中包括多个宽度不同的波导，因而上述光栅耦合器总的归一化透射谱为多个宽度不同的波导的 子归一化透射谱的叠加，从而能够提高光栅耦合器的带宽。
示例性的，这里将以TE偏振相关的光栅耦合器为例进行详细描述。在图5所示的波导芯层中，波导阵列中的波导可以均为TE偏振相关的波导。具体的，波导芯层的厚度可以是0.2-0.4μm，亚微米波导的宽度可以是0.4-0.6μm，与之连接的第一锥形波导的宽端的宽度可以是20-40μm，波导阵列的长度可以是20-40μm，波导阵列的宽度可以是20-30μm。波导链的一个周期内可以包括一个宽波导和一个窄波导，宽波导的宽度可以是200-700nm，窄波导的宽度可以在250nm以下，但第一波导群71中的宽波导即第二波导92与第二波导群72中的宽波导即第三波导93的具体宽度值可以不同，第一波导群71中的窄波导即第一波导91与第二波导群72中的窄波导即第四波导94的具体宽度值可以不同，这样波导阵列便可以包含有四个不同宽度的波导，对应四个不同的有效折射率，从而产生四个耦合中心波长及归一化透射谱。
举例来说，当待耦合光信号的中心波长为1550nm时，可以设定指定中心波长分别为1520nm、1540nm、1560和1580，第一波导群71中两个不同宽度的波导传输TE偏振模式的光信号时的耦合中心波长可以分别为1520nm和1540nm，这两个波导分别在传输指定中心波长为1520nm和1540nm的TE偏振模式的光信号时的耦合效率最高，这两个耦合中心波长分别对应的子归一化透射谱叠加后的归一化透射谱对应的耦合中心波长为1530nm。而第二波导群72中两个不同宽度的波导在传输TE偏振模式的光信号时的耦合中心波长可以分别为1560nm和1580nm，这两个波导分别在传输指定中心波长为1560nm和1580nm的TE偏振模式的光信号时的耦合效率最高，这两个耦合中心波长分别对应的子归一化透射谱叠加后的归一化透射谱对应的耦合中心波长为1570nm。将分别对应四个耦合中心波长的子归一化透射谱进行叠加可以得到如图6所示的光栅耦合器总的归一化透射谱。光栅耦合器对中心波长为1550nm的光信号的耦合效果示意图可以参见图7。需要说明的是，这里的参数值只是举例说明，本发明实施例不做限定。
由图6可知，光栅耦合器在传输TE偏振模式的光信号时的耦合中心波长为1550nm，与待耦合光信号的中心波长一致，因而在传输TE偏振模式的待耦合光信号时的耦合效率最高。同时，在图6中，光栅耦合器总的归一化透射谱的3dB带宽对应的波长范围为100nm左右，即TE偏振相关的光栅耦合器的带宽提高到了12.5THz左右。因而，与现有技术相比，本发明实施例提供的TE偏振相关的光栅耦合器可以显著提高传输指定中心波长的TE偏振模式的光信号时的带宽，进而可以显著提高可传输的光信号的信息量。
与TE偏振相关的光栅耦合器类似，TM偏振相关的光栅耦合器可以提高传输指定中心波长的TM偏振模式的光信号时的耦合效率及带宽。
由于TE偏振相关的光栅耦合器可以保证在传输指定中心波长的TE偏振模式的光信号时具有较高的耦合效率，而不能保证在传输指定中心波长的TM偏振模式的光信号时具有较高的耦合效率，因而TE偏振相关的光栅耦合器具有较强的偏振依赖性。具体来说，当某一TE偏振相关的光栅耦合器在传输TE偏振相关的光信号时的耦合中心波长为1550nm时，该波导在传输TM偏振模式的光信号时的耦合中心波长为1556nm，而并不是1550nm。若待耦合光信号的中心波长为1550nm，则该光栅耦合器在传输TE偏振模式的光信号时的耦合效率高，而在传输TM偏振模式的光信号的耦合效率较低，使得光栅耦合器在传输指定中心波长的TE和TM偏振模式的光信号时的耦合效率的差值较大，从而使得偏振相关损耗(Polarization Dependent Loss，PDL)较大。对于任一指定中心波长来说，这里的PDL是指在传输TE偏振模式的光信号和TM偏振模式的光信号时，较高耦合效率与较低耦合效率的比值。同样，对于TM偏振相关的光栅耦合器也会存在传输指定中心波长的TM偏振模式的光信号时的耦合效率较高的同时，不能保证在传输指定中心波长的TE偏振模式的光信号时具有较高的耦合效率。
又由于待耦合光信号通常不是完全的TE偏振模式的光信号，或者完全的TM偏振模式的光信号，而往往可以分解为相互正交的TE偏振分量 和TM偏振分量，且TE/TM偏振相关的光栅耦合器只能保证对其中一种偏振分量的光信号的耦合效率较高，而不能保证对另一种偏振分量的耦合效率也较高，即PDL较大。因而，TE/TM偏振相关的光栅耦合器对光信号的总的耦合效率较低。
情况2：
波导阵列中的波导可以包括水平极化TE偏振相关的波导和垂直极化TM偏振相关的波导，TE偏振相关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第一预设阈值，TM偏振相关的波导在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于第一预设阈值。
由情况1可知，当光栅耦合器波导阵列中宽度不同的波导包括TE偏振相关的波导时，可以提高光栅耦合器在传输指定中心波长的TE偏振模式的光信号时的耦合效率和带宽；当光栅耦合器波导阵列中宽度不同的波导包括TM偏振相关的波导时，可以提高光栅耦合器在传输指定中心波长的TM偏振相关的光信号时的耦合效率和带宽。因而在情况2中，当光栅耦合器波导阵列中宽度不同的波导同时包括TE偏振相关的波导和TM偏振相关的波导时，可以同时提高光栅耦合器在传输指定中心波长的TE偏振模式的光信号时的耦合效率和带宽，以及在传输指定中心波长的TM偏振相关的光信号时的耦合效率和带宽。且当光信号包括TE偏振分量和TM偏振分量时，该光栅耦合器能够提高在传输指定中心波长的光信号时总的耦合效率和带宽。
可见，情况2中的光栅耦合器可以提高在传输指定中心波长时的光信号的耦合带宽和耦合效率，而与偏振模式无关，因而可以称为偏振无关的光栅耦合器。
在情况2提供的偏振无关的光栅耦合器中，本发明实施例对波导阵列中TE偏振相关的波导和TM偏振相关的波导的数量和位置并不具体限定。示例性的，部分波导群中的波导可以为TE偏振相关的波导，其它波导群中的波导可以为TM偏振相关的波导；或者，任一波导链中的部分波 导可以为TE偏振相关的波导，而其余波导可以为TM偏振相关的波导。
可选地，波导阵列中的波导链为TE偏振相关的波导链或TM偏振相关的波导链，且TE偏振相关的波导链与TM偏振相关的波导链相邻排列。其中，TE偏振相关的波导链中的波导均为TE偏振相关的波导，TM偏振相关的波导链中的波导均为TM偏振相关的波导。示例性的，本发明实施例提供的一种偏振无关的光栅耦合器波导芯层的俯视图可以参见图8。其中，波导阵列6包括第三波导群73、第四波导群74、第五波导群75和第六波导群76，每个波导群中包括两条波导链，斜线填充的波导为TM偏振相关的波导，其它波导为TE偏振相关的波导。
优选地，波导阵列中TE偏振相关的波导和TM偏振相关的波导相邻排列。具体的，在任一波导链中，TE偏振相关的波导和TM偏振相关的波导可以相邻排列，且位于相邻波导链中的两个相邻波导可以分别为TE偏振相关的波导和TM偏振相关的波导。示例性的，在图5所示的波导阵列中，第一波导和第四波导可以为TM偏振相关的波导，且第二波导和第三波导可以为TE偏振相关的波导，具体可以参见图9所示的波导芯层的结构，其中，斜线填充的波导为TM偏振相关的波导，其它波导为TE偏振相关的波导。其中，在第一波导链中，相邻排列的第一波导和第二波导分别为TM偏振相关的波导和TE偏振相关的波导；在第二波导链中，相邻排列的第三波导和第四波导分别为TE偏振相关的波导和TM偏振相关的波导；第一波导链中的第一波导与第二波导链中的第三波导相邻且分别为TM偏振相关的波导和TE偏振相关的波导；第一波导链中的第二波导与第二波导链中的第四波导相邻且分别为TE偏振相关的波导和TM偏振相关的波导。
由于光信号通常可以分解为TE偏振模式和TM偏振模式，且通过光栅耦合器进行耦合时光信号的光斑很小，因而光斑与光栅耦合器对应的面积很小，当TE偏振相关的波导和TM偏振相关的波导相邻排列时，可以使得光栅耦合器在对应光斑区域内同时包括多个TE偏振相关的波导和TM偏振相关的波导，从而使得光信号中的TE偏振分量可以被多个TE偏振相关的波导耦合进光栅耦合器，而TM偏振分量可以被与TE偏振相 关的波导相邻的多个TM偏振相关的波导耦合进光栅耦合器，从而可以提高光栅耦合器对光信号的耦合效率。
情况3：
波导阵列中的波导包括偏振无关的波导，偏振无关的波导在传输指定中心波长的TE偏振模式的光信号和在传输指定中心波长的TM偏振模式的光信号时的偏振相关损耗小于第二预设阈值。
其中，第二预设阈值通常较小(例如可以为0.1dB)，具体可以根据实际情况进行设定，这里不做限定。PDL小于第二预设阈值，即PDL很小，可以使得偏振无关的波导在传输指定中心波长的TE偏振模式的光信号和传输指定中心波长的TM偏振模式的光信号时的耦合效率相近，即偏振模式对偏振无关的波导的耦合效率的影响不大。
进一步地，偏振无关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率可以大于第三预设阈值，且在传输指定中心波长的TM偏振模式的光信号时的耦合效率可以大于第三预设阈值。这里的第三预设阈值也较大(例如可以是80％)，但通常可以小于第一预设阈值。也就是说，偏振无关的波导可以保证在传输指定中心波长的TE偏振模式的光信号时具有较高的耦合效率，同时在传输指定中心波长的TM偏振模式的光信号时也具有较高的耦合效率。并且，当光信号包括TE偏振分量和TM偏振分量时，偏振无关的波导可以对两种偏振分量均具有较高的耦合效率。因而，当光栅耦合器包括多个偏振无关的波导时可以提高在传输光信号时耦合效率，而与光信号的偏振模式无关，因而也可以成为偏振无关的光栅耦合器。
同时，由于任一宽度的波导在传输TE偏振模式的光信号时，可以产生一个与TE偏振模式对应的耦合中心波长及子归一化透射谱；同时，在传输TM偏振模式的光信号时，还可以产生一个与TM偏振模式对应的耦合中心波长及子归一化透射谱。因而，该光栅耦合器对应的TE偏振模式的归一化透射谱是宽度不同的多个偏振无关的波导产生的子归一化透射谱的叠加；同时，该光栅耦合器对应的TM偏振模式的归一化透射谱也是宽度不同的多个偏振无关的波导产生的子归一化透射谱的叠加。因此，无 论光信号是TE偏振模式还是TM偏振模式，本发明实施例提供的光栅耦合器均可以提高光信号的耦合带宽，进而可以提高可传输的光信号的信息量。
可见，情况3中提供的光栅耦合器可以提高光信号的耦合带宽和耦合效率，而不受光信号的偏振模式的限制，因而也可以称为偏振无关的光栅耦合器。
示例性的，本发明实施例提供的一种偏振无关的光栅耦合器的俯视图可以参见图10，网格填充的狭缝波导为偏振无关的波导，斜线填充的对称波导为TM偏振相关的波导，其它波导为TE偏振相关的波导。当然，偏振无关的波导以外的波导也可以均为TE偏振相关的波导，或者均为TM偏振相关的波导。本发明实施例对光栅耦合器中偏振无关的波导的数量和位置不做限定。
优选地，波导阵列中的波导也可以均为偏振无关的波导，此时波导阵列中任一波导均可以使得TE偏振模式和TM偏振模式的光信号的耦合效率较高，从而能够更好地提高光信号的耦合效率。
示例性的，本发明实施例提供的一种偏振无关的光栅耦合器波导芯层的俯视图可以参见图11，网格填充的狭缝波导和网格填充的对称波导均为偏振无关的波导。波导芯层的厚度可以是220nm，波导阵列可以包括两个波导群，任一波导链的一个周期内可以包括两个宽度不同的波导。宽波导可以为偏振无关的狭缝波导，窄波导可以为偏振无关的对称波导。窄波导的宽度可以在220nm附近，这样的窄波导在TE偏振模式下的有效折射率与在TM偏振模式下的有效折射率相近，从而可以使得两个折射率分别对应的TE和TM偏振模式下的耦合中心波长的差值在预设阈值内，示例性的该宽度范围内偏振无关的对称波导对应的TE偏振模式和TM偏振模式的模场分布可以参见图12；狭缝波导的宽度可以在400nm附近，狭缝的宽度可以在100nm附近，这样的狭缝波导对应的TE偏振模式下的有效折射率与TM偏振模式下的有效折射率相近，从而可以使得分别对应的TE/TM偏振模式的耦合中心波长的差值在预设阈值内。示例性的，上述 宽度范围内偏振无关的狭缝波导对应的TE偏振模式和TM偏振模式的模场分布可以参见图13。当然，对于波导的具体宽度值可以根据需要进行设定，这里不做限定。
进一步地，在情况1、情况2、情况3所提供的上述光栅耦合器的基础上，波导阵列中还可以包括第二锥形波导，用于连接波导链中宽度不同的波导，从而可以减小光信号由一个波导转换到宽度不同的另一波导进行传输时的能量损耗。示例性的，包括第二锥形波导10的波导芯层的俯视图可以参见如图14。
上述光栅耦合器中，波导阵列中的波导链可以平行排列；或者，波导链还可以成一定角度排列成扇环波导阵列。当波导链成一定角度排列成扇环波导阵列再与第一锥形波导连接时，可以减小第一锥形波导的长度，从而节约第一锥形波导所占用的面积。示例性的，一种具有扇环波导阵列的光栅耦合器的波导芯层的俯视图可以参见图15。其中，扇环波导阵列的长度可以是10-15μm，半径可以是10-30μm。
需要说明的是，波导阵列中也可以包括两个以上的波导群，例如图8所示的波导阵列中包括四个波导群；且波导链的任一周期中也可以包括两个以上的波导，本发明实施例不做限定。
上述光栅耦合器中，波导阵列中的波导可以为条波导、脊波导或狭缝波导或其它类型的波导，这里不做限定。此外，上述光栅耦合器中的亚微米波导也可以为条波导、脊波导或狭缝波导或其它类型的波导。
此外，上述光栅耦合器中，衬底层未与下限制层接触的一面还可以有分布式布拉格反射镜(Distributed Bragg Reflection，DBR)或金属反射层，以提高光栅耦合器内部的光信号在衬底层的反射率，避免光信号从衬底层泄露出光栅耦合器，从而可以提高光栅耦合器的耦合效率。
并且，在上述光栅耦合器中，还可以在光信号的入射面覆盖有多晶硅层，以减少外部光信号在光栅耦合器入射面的信号反射，从而可以提高能够衍射进光栅耦合器的光信号，提高光栅耦合器的耦合效率。
当然，在上述光栅耦合器的基础上，还可以结合折射率匹配液或现有技术领域的其它相关技术，以提高光栅耦合器的耦合效率，本发明实施例不做限定。
需要说明的是，本发明实施例给出的光栅耦合器中各部分的参数值只是举例说明，具体可以根据实际情况进行设定，本发明实施例并不限定。
本发明实施例提供一种光栅耦合器，在光栅耦合器波导芯层的波导阵列中包括至少两个波导群，每个波导群包括至少一条波导链，每条波导链包括至少两个宽度不同的波导，从而使得光栅耦合器中可以包括多个宽度不同的波导，可以对应多个不同的有效折射率，从而可以产生多个耦合中心波长及归一化透射谱。因而，光栅耦合器总的归一化透射谱是多个宽度不同的波导的子归一化透射谱的叠加，与通常仅包括一种宽度的波导的传统光栅耦合器的归一化透射谱相比，本发明实施例提供的光栅耦合器可以显著提高带宽，从而能够解决现有技术中传统光栅耦合器带宽小的问题。
本发明实施例提供一种光栅耦合器的制备方法，参见图16，其主要步骤可以包括：
101、制备衬底层。
102、在衬底层的基础上，制备下限制层。
103、在下限制层的基础上，制备波导芯层。
波导芯层包括亚微米波导、第一锥形波导和波导阵列；波导阵列包括至少两个波导群，波导群包括至少一条波导链，波导链包括至少两个宽度不同的波导，波导链中的波导相互连接，同一波导群包括的波导链中波导的宽度和排列结构相同，不同波导群包括的波导链中波导的宽度和/或排列结构不同。其中，波导阵列中波导链的一端与第一锥形波导宽的一端连接，第一锥形波导窄的一端与亚微米波导连接。
104、在波导芯层的基础上，制备上限制层。
通过上述制备步骤获得的光栅耦合器中，由于波导阵列可以包括至少两个不同的波导群，每个波导群可以包括至少一条波导链，每条波导链 可以包括至少两个宽度不同的波导，且同一波导群包括的波导链中波导的宽度和排列结构相同，不同波导群包括的波导链中波导的宽度和/或排列结构不同，因而光栅耦合器中可以包括多个宽度不同的波导。由于宽度不同的波导对应的光信号的有效折射率不同，因而多个宽度不同的波导可以对应多个不同的有效折射率，从而可以产生多个耦合中心波长以及多个耦合中心波长对应的归一化透射谱。因此，光栅耦合器总的归一化透射谱为多个宽度不同的波导所产生的不同耦合中心波长对应的子归一化透射谱的叠加。与通常仅包括一种宽度的波导(例如图1所示)的传统光栅耦合器的归一化透射谱相比，本发明实施例提供的光栅耦合器总的归一化透射谱中3dB波长范围明显增大，从而有效提高了光栅耦合器的带宽，进而增大了可传输的光信号的信息量。
参见图17，步骤103中制备波导芯层具体可以包括步骤201-204：
201、制备波导。
待耦合光信号通常为通信中常用的中心波长的光信号例如1550nm，在制备波导时可以首先根据待耦合光信号的中心波长设定指定中心波长。指定中心波长通常在待耦合光信号的中心波长附近，当波导的耦合中心波长在预设指定中心波长附近时，多个宽度不同的波导的子归一化透射谱叠加后的归一化透射谱对应的耦合中心波长在待耦合光信号的中心波长附近，此时光栅耦合器在传输待耦合光信号时具有较高的耦合效率。示例性的，当待耦合光信号的中心波长为1550nm时，指定中心波长可以为1520nm、1540nm、1560nm和1570nm。根据指定中心波长确定使得耦合中心波长分别与指定中心波长在一定差值范围(该差值范围通常较小)内的波导的宽度的集合。由于越靠近耦合中心波长耦合效率越高，因而当耦合中心波长在指定中心波长附近时，波导对指定中心波长的光信号的耦合效率较高。根据宽度集合内的不同宽度值制备宽度不同的波导，可以使得光栅耦合器包括多个宽度不同的波导，使得光栅耦合器的归一化透射谱为多个宽度不同的波导的子归一化透射谱的叠加，从而可以有效提高带宽。
本步骤中制备的波导可以为条波导、脊波导、狭缝波导或其它类型 的波导，这里不做限定。
202、将宽度不同的至少两个波导连接形成波导链。
该步骤可以使得波导链中包括多个宽度不同的波导。其中，宽度不同的波导可以周期性排列也可以伪周期性排列，这里不做限定。
203、将波导链排列成波导阵列，使得波导阵列包括至少两个波导群，波导群包括至少一条波导链，同一波导群包括的波导链中波导的宽度和排列结构相同，不同波导群包括的波导链中波导的宽度和/或排列结构不同。
其中，波导链排列成的波导阵列形成了光栅，这里的光栅可以是均匀光栅也可以是非均匀光栅，待耦合光信号可以通过光栅及衍射特性进行耦合。波导阵列中的波导链可以平行排列，也可以成一定角度排列成扇环波导阵列，以减小与之连接的第一锥形波导的长度，节约第一锥形波导所占用的面积。
204、将波导阵列中波导链的一端与第一锥形波导宽的一端连接，将第一锥形波导窄的一端与亚微米波导连接，从而形成波导芯层。
进一步地，波导阵列中波导链中相邻两个波导的宽度可以不同，位于相邻波导链上的两个相邻波导的宽度可以不同。具体的，可以在步骤202和步骤203中，将宽度不同的波导交错排列，从而可以减少面积浪费，尽可能大地利用了波导芯层的面积，使得结构更加紧凑，提高了波导的数量及在波导芯层的分布率，从而提高了光栅耦合器的耦合效率。
具体的，上述步骤201具体可以包括：
301、根据光栅方程确定指定中心波长对应的有效折射率的集合。
光栅方程表明了耦合中心波长与有效折射率的对应关系，因而可以根据光栅方程确定指定中心波长对应的有效折射率的集合。
302、根据有效折射率的集合，确定波导的宽度集合，并根据波导的宽度集合制备波导。
由于不同偏振模式的光信号的特性、边界条件及其它因素不同，同 一宽度的波导对应的不同偏振模式的有效折射率不同，即在不同偏振模式下，同一有效折射率对应的波导的宽度不同，因而步骤302具体可以包括步骤401-402以及步骤501-502两种情况：
401、在水平极化TE偏振模式下，根据有效折射率的集合确定TE偏振相关的波导的宽度集合。其中，TE偏振相关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第一预设阈值。对TE偏振相关的波导的描述具体可以参见装置实施例。
402、根据TE偏振相关的波导的宽度集合，制备TE偏振相关的波导。
在步骤401中确定TE偏振相关的波导的宽度集合后，可以根据TE偏振相关的波导的宽度集合中的宽度值，制备相应宽度的TE偏振相关的波导，从而可以使得波导阵列中包括多个宽度不同的TE偏振相关的波导，使得光栅耦合器的归一化透射谱为多个宽度不同的TE偏振相关波导的归一化透射谱的叠加，从而可以显著提高预设波长范围内TE偏振光信号的耦合带宽，有效增大可传输的TE偏振光信号的信息量。
或者，步骤302可以包括：
501、在垂直极化TM偏振模式下，根据有效折射率的集合确定TM偏振相关的波导的宽度集合。其中，TM偏振相关的波导在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于第一预设阈值。对TM偏振相关的波导的描述具体可以参见装置实施例。
502、根据TM偏振相关的波导的宽度集合，制备TM偏振相关的波导。
在步骤501中确定TM偏振相关的波导的宽度集合后，可以根据TM偏振相关的波导的宽度集合中的宽度值，制备相应宽度的TM偏振相关的波导，从而可以使得波导阵列中包括多个宽度不同的TM偏振相关的波导，使得光栅耦合器的归一化透射谱为多个宽度不同的TM偏振相关波导的归一化透射谱的叠加，从而可以显著提高预设波长范围内TM偏振光信号的耦合带宽，有效增大可传输的TM偏振光信号的信息量。
可选地，波导阵列中的波导包括TE偏振相关的波导和TM偏振相关的波导。具体的，可以在波导阵列中同时包括由步骤401、402获得的宽度不同的TE偏振相关的波导，和由步骤501、502获得的宽度不同的TM偏振相关的波导，从而可以提高光栅耦合器的耦合带宽和耦合效率以及可传输的光信号的信息量，具体可以参见装置实施例中的描述。更进一步地，还可以在波导阵列中将TE偏振相关的波导和TM偏振相关的波导相间排列，从而更好地提高光栅耦合器的耦合效率，具体可以参见装置实施例中的描述。
可选地，波导阵列中的波导包括偏振无关的波导，偏振无关的波导在传输指定中心波长的TE偏振模式的光信号和在传输指定中心波长的TM偏振模式的光信号时的偏振相关损耗PDL小于第二预设阈值。进一步地，偏振无关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第三预设阈值，且在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于第三预设阈值。具体的，在步骤201中制备偏振无关的波导具体可以包括：
601、根据光栅方程以及TE偏振模式下有效折射率与TE偏振相关的波导的宽度的对应关系，确定第一映射关系，第一映射关系为TE偏振模式下耦合中心波长与TE偏振相关的波导的宽度的映射关系。
602、根据光栅方程以及垂直极化TM偏振模式下有效折射率与TM偏振相关的波导的宽度的对应关系，确定第二映射关系，第二映射关系为TM偏振模式下耦合中心波长与TM偏振相关的波导的宽度的映射关系。
603、根据第一映射关系以及第二映射关系，确定偏振无关的波导的宽度集合，以使得宽度在宽度集合内的偏振无关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第三预设阈值，且在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于第三预设阈值。
604、根据偏振无关的波导的宽度集合，制备偏振无关的波导。
根据步骤603确定的宽度集合制备偏振无关的波导，可以使得波导 阵列中包括多个偏振无关的波导，或者可以使得波导阵列中的波导均为偏振无关的波导，从而可以提高光栅耦合器对光信号的耦合带宽和耦合效率、以及可传输的光信号的信息量，具体可以参见装置实施例中的描述。
进一步地，上述步骤202具体可以包括：将宽度不同的至少两个波导通过第二锥形波导连接形成波导链。其中，用以连接宽度不同的波导的第二锥形波导，可以减小光信号由一个宽度波导转换到宽度不同的另一波导进行传输时的能量损耗。
此外，在本发明实施例提供的上述光栅耦合器中，还可以结合DBR、金属反射层、多晶硅层、折射率匹配液等现有技术，以提高光栅耦合器的耦合效率。
本发明实施例提供一种光栅耦合器的制备方法，制备获得的光栅耦合器波导芯层的波导阵列中包括至少两个波导群，每个波导群包括至少一条波导链，每条波导链包括至少两个宽度不同的波导，从而使得光栅耦合器中可以包括多个宽度不同的波导，可以对应多个不同的有效折射率，从而可以产生多个耦合中心波长及归一化透射谱。因而，光栅耦合器总的归一化透射谱是多个宽度不同的波导的子归一化透射谱的叠加，与通常仅包括一种宽度的波导的传统光栅耦合器的归一化透射谱相比，本发明实施例提供的光栅耦合器可以显著提高带宽，从而能够解决现有技术中传统光栅耦合器带宽小的问题。
在本申请所提供的几个实施例中，应该理解到，所揭露的光栅耦合器和制备方法，可以通过其它的方式实现。以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (20)

  1. 一种光栅耦合器，其特征在于，包括：
    依次排列的衬底层、下限制层、波导芯层和上限制层；
    所述波导芯层包括亚微米波导、第一锥形波导和波导阵列；
    所述波导阵列包括至少两个波导群，所述波导群包括至少一条波导链，所述波导链包括至少两个宽度不同的波导，所述波导链中的所述波导相互连接，同一所述波导群包括的所述波导链中波导的宽度和排列结构相同，不同所述波导群包括的所述波导链中波导的宽度和/或排列结构不同；
    其中，所述波导阵列中所述波导链的一端与所述第一锥形波导宽的一端连接，所述第一锥形波导窄的一端与所述亚微米波导连接。
  2. 根据权利要求1所述的光栅耦合器，其特征在于，所述波导链中相邻两个波导的宽度不同，位于相邻波导链上的两个相邻波导的宽度不同。
  3. 根据权利要求2所述的光栅耦合器，其特征在于，所述波导阵列包括第一波导群和第二波导群，所述第一波导群包括第一波导链，所述第二波导群包括第二波导链；
    所述第一波导链包括第一波导和第二波导，所述第一波导与所述第二波导的宽度不同且相邻排列；
    所述第二波导链包括第三波导和第四波导，所述第三波导与所述第四波导的宽度不同且相邻排列；
    所述第一波导与所述第三波导的宽度不同且相邻排列；
    所述第二波导与所述第四波导的宽度不同且相邻排列。
  4. 根据权利要求1-3任一项所述的光栅耦合器，其特征在于，所述波导阵列中的所述波导包括水平极化TE偏振相关的波导和垂直极化TM偏振相关的波导；
    其中，所述TE偏振相关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第一预设阈值；所述TM偏振相关的波导在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第 一预设阈值。
  5. 根据权利要求4所述的光栅耦合器，其特征在于，所述波导阵列中的所述波导链为TE偏振相关的波导链或TM偏振相关的波导链，且所述TE偏振相关的波导链与所述TM偏振相关的波导链相邻排列；
    其中，所述TE偏振相关的波导链中的所述波导均为所述TE偏振相关的波导，所述TM偏振相关的波导链中的所述波导均为所述TM偏振相关的波导。
  6. 根据权利要求4所述的光栅耦合器，其特征在于，所述波导阵列中所述TE偏振相关的波导和所述TM偏振相关的波导相邻排列。
  7. 根据权利要求3所述的光栅耦合器，其特征在于，所述第一波导和所述第四波导为TM偏振相关的波导，且所述第二波导和所述第三波导为TE偏振相关的波导。
  8. 根据权利要求1-3任一项所述的光栅耦合器，其特征在于，所述波导阵列中的所述波导包括偏振无关的波导，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号和在传输指定中心波长的TM偏振模式的光信号时的偏振相关损耗PDL小于第二预设阈值。
  9. 根据权利要求8所述的光栅耦合器，其特征在于，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第三预设阈值，且在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第三预设阈值。
  10. 根据权利要求9所述的光栅耦合器，其特征在于，所述波导阵列中的所述波导均为所述偏振无关的波导。
  11. 根据权利要求1-10任一项所述的光栅耦合器，其特征在于，还包括：
    第二锥形波导，用于连接所述波导链中宽度不同的所述波导。
  12. 根据权利要求1-11任一项所述的光栅耦合器，其特征在于，所述波导链平行排列；
    或者，所述波导链成一定角度排列成扇环波导阵列。
  13. 根据权利要求1-12任一项所述的光栅耦合器，其特征在于， 所述波导阵列中的所述波导为条波导、脊波导或狭缝波导。
  14. 一种光栅耦合器的制备方法，其特征在于，包括：
    制备衬底层；
    在所述衬底层的基础上，制备下限制层；
    在所述下限制层的基础上，制备波导芯层，所述波导芯层包括亚微米波导、第一锥形波导和波导阵列；所述波导阵列包括至少两个波导群，所述波导群包括至少一条波导链，所述波导链包括至少两个宽度不同的波导，所述波导链中的所述波导相互连接，同一所述波导群包括的所述波导链中波导的宽度和排列结构相同，不同所述波导群包括的所述波导链中波导的宽度和/或排列结构不同；
    其中，所述波导阵列中所述波导链的一端与所述第一锥形波导宽的一端连接，所述第一锥形波导窄的一端与所述亚微米波导连接；
    在所述波导芯层的基础上，制备上限制层。
  15. 根据权利要求14所述的方法，其特征在于，所述制备波导芯层包括：
    制备所述波导；
    将宽度不同的至少两个所述波导连接形成所述波导链；
    将所述波导链排列成所述波导阵列，使得所述波导阵列包括至少两个所述波导群，所述波导群包括至少一条波导链，同一所述波导群包括的所述波导链中波导的宽度和排列结构相同，不同所述波导群包括的所述波导链中波导的宽度和/或排列结构不同；
    将所述波导阵列中所述波导链的一端与所述第一锥形波导宽的一端连接，将所述第一锥形波导窄的一端与所述亚微米波导连接，从而形成所述波导芯层。
  16. 根据权利要求14或15所述的方法，其特征在于，所述波导链中相邻两个波导的宽度不同，位于相邻波导链上的两个相邻波导的宽度不同。
  17. 根据权利要求14-16任一项所述的方法，其特征在于，所述波导阵列中的所述波导包括水平极化TE偏振相关的波导和垂直极化TM 偏振相关的波导；
    其中，所述TE偏振相关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第一预设阈值；所述TM偏振相关的波导在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第一预设阈值。
  18. 根据权利要求14-16任一项所述的方法，其特征在于，所述波导阵列中的所述波导包括偏振无关的波导，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号和在传输指定中心波长的TM偏振模式的光信号时的偏振相关损耗PDL小于第二预设阈值。
  19. 根据权利要求18所述的方法，其特征在于，所述偏振无关的波导在传输指定中心波长的TE偏振模式的光信号时的耦合效率大于第三预设阈值，且在传输指定中心波长的TM偏振模式的光信号时的耦合效率大于所述第三预设阈值。
  20. 根据权利要求14-19任一项所述的方法，其特征在于，所述波导链中宽度不同的所述波导通过第二锥形波导连接。
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110389407A (zh) * 2018-04-19 2019-10-29 北京万集科技股份有限公司 光学天线、相控阵激光雷达及光学天线的制备方法
US11428869B2 (en) * 2019-04-22 2022-08-30 The Chinese University Of Hong Kong Multimode waveguide grating coupler

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105874314B (zh) * 2014-04-15 2018-12-07 华为技术有限公司 光波导群速度延时测量装置及方法
US10935720B2 (en) 2019-04-29 2021-03-02 Ii-Vi Delaware, Inc. Laser beam product parameter adjustments
ES2872650B2 (es) * 2020-04-29 2022-03-11 Univ Malaga Guia de onda periodica sub-longitud de onda enladrillada, adaptador modal, divisor de potencia y divisor de polarizacion que hacen uso de dicha guia de onda
US11448828B2 (en) * 2021-02-22 2022-09-20 Taiwan Semiconductor Manufacturing Company, Ltd. Optical device for coupling light
US11754784B2 (en) 2021-09-08 2023-09-12 Cisco Technology, Inc. Grating coupler
CN114089482B (zh) * 2021-12-02 2022-10-18 清华大学 一种光栅耦合器

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101106164A (zh) * 2007-06-29 2008-01-16 中国电子科技集团公司第十三研究所 一种用于量子阱红外探测器的交叉组合式双周期光栅
CN101556356A (zh) * 2009-04-17 2009-10-14 北京大学 一种光栅耦合器及其在偏振和波长分束上的应用
CN101833138A (zh) * 2010-04-30 2010-09-15 华中科技大学 一种偏振无关光栅耦合器的制作方法
CN101995609A (zh) * 2010-09-15 2011-03-30 中国科学院半导体研究所 绝缘体上硅的缓变阶梯型波导光栅耦合器及制作方法
CN103197386A (zh) * 2013-04-01 2013-07-10 北京工业大学 一种金属键合的垂直耦合光栅耦合器及其制作方法
US20140169739A1 (en) * 2012-12-17 2014-06-19 Hon Hai Precision Industry Co., Ltd. Waveguide lens for coupling laser light source and optical element
CN103901563A (zh) * 2014-03-31 2014-07-02 北京工业大学 一种折射率可调的光栅耦合器及其制作方法
CN104090333A (zh) * 2014-06-23 2014-10-08 天津工业大学 一种二元闪耀光栅耦合器及其在硅基混合集成光探测器上的应用

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07128530A (ja) * 1993-10-29 1995-05-19 Oki Electric Ind Co Ltd 光波長フィルタ
US6823111B2 (en) * 2000-07-31 2004-11-23 Spectalis Corp. Optical waveguide filters
US6853769B2 (en) * 2001-03-16 2005-02-08 Lightwave Microsystems Corporation Arrayed waveguide grating with waveguides of unequal widths
US6912331B2 (en) * 2002-03-12 2005-06-28 Cambrius Inc. Periodic electromagnetic waveguide structures with controlled polarization properties
AU2003265243A1 (en) * 2002-05-30 2003-12-19 Massachusetts Institute Of Technology Optical waveguide with non-uniform sidewall gratings
CA2489898C (en) * 2003-12-19 2009-08-18 Nec Corporation Low loss awg muliplexer
FR2922031B1 (fr) 2007-10-03 2011-07-29 Commissariat Energie Atomique Dispositif optique a circuits photoniques superposes, pour couplage avec un ou plusieurs guides optiques.
JP4448199B2 (ja) * 2008-02-29 2010-04-07 株式会社フジクラ 基板型光導波路素子、波長分散補償素子、光フィルタならびに光共振器、およびそれらの設計方法
WO2009107808A1 (ja) * 2008-02-29 2009-09-03 株式会社フジクラ 基板型光導波路素子、波長分散補償素子およびその設計方法、光フィルタおよびその設計方法、ならびに光共振器およびその設計方法
EP2103974A1 (en) * 2008-03-21 2009-09-23 Nitto Denko Corporation Optical waveguide having grating and method of forming the same
WO2013058769A1 (en) 2011-10-21 2013-04-25 Hewlett-Packard Development Company, L.P. Grating couplers with deep-groove non-uniform gratings
US9091827B2 (en) * 2012-07-09 2015-07-28 Luxtera, Inc. Method and system for grating couplers incorporating perturbed waveguides
WO2017189857A1 (en) * 2016-04-28 2017-11-02 Analog Photonics LLC Optical phase shifter device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101106164A (zh) * 2007-06-29 2008-01-16 中国电子科技集团公司第十三研究所 一种用于量子阱红外探测器的交叉组合式双周期光栅
CN101556356A (zh) * 2009-04-17 2009-10-14 北京大学 一种光栅耦合器及其在偏振和波长分束上的应用
CN101833138A (zh) * 2010-04-30 2010-09-15 华中科技大学 一种偏振无关光栅耦合器的制作方法
CN101995609A (zh) * 2010-09-15 2011-03-30 中国科学院半导体研究所 绝缘体上硅的缓变阶梯型波导光栅耦合器及制作方法
US20140169739A1 (en) * 2012-12-17 2014-06-19 Hon Hai Precision Industry Co., Ltd. Waveguide lens for coupling laser light source and optical element
CN103197386A (zh) * 2013-04-01 2013-07-10 北京工业大学 一种金属键合的垂直耦合光栅耦合器及其制作方法
CN103901563A (zh) * 2014-03-31 2014-07-02 北京工业大学 一种折射率可调的光栅耦合器及其制作方法
CN104090333A (zh) * 2014-06-23 2014-10-08 天津工业大学 一种二元闪耀光栅耦合器及其在硅基混合集成光探测器上的应用

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3296782A4 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110389407A (zh) * 2018-04-19 2019-10-29 北京万集科技股份有限公司 光学天线、相控阵激光雷达及光学天线的制备方法
CN110389407B (zh) * 2018-04-19 2021-02-02 北京万集科技股份有限公司 光学天线、相控阵激光雷达及光学天线的制备方法
US11428869B2 (en) * 2019-04-22 2022-08-30 The Chinese University Of Hong Kong Multimode waveguide grating coupler

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