• Chinese Optics Letters
  • Vol. 23, Issue 1, 013603 (2025)
Pengfei Fan, Xiaotian Zhang, Chi Zhang, Shanshan Cheng..., Xiao-Hui Tian*, Kunpeng Jia, Hua-Ying Liu**, Shining Zhu and Zhenda Xie***|Show fewer author(s)
Author Affiliations
  • National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, School of Electronic Science and Engineering, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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    DOI: 10.3788/COL202523.013603 Cite this Article Set citation alerts
    Pengfei Fan, Xiaotian Zhang, Chi Zhang, Shanshan Cheng, Xiao-Hui Tian, Kunpeng Jia, Hua-Ying Liu, Shining Zhu, Zhenda Xie, "Mode-selective edge coupler with cladding grating for a lithium-niobate-on-insulator waveguide," Chin. Opt. Lett. 23, 013603 (2025) Copy Citation Text show less
    Schematic of the LNOI edge coupler with cladding grating. Top panel: 3D schematic structure and principle of the grating edge coupler. Bottom panel: cross-sections at different positions.
    Fig. 1. Schematic of the LNOI edge coupler with cladding grating. Top panel: 3D schematic structure and principle of the grating edge coupler. Bottom panel: cross-sections at different positions.
    Phase-matching condition and modal distributions. (a) Grating period Λ for momentum compensation at different wavelengths. (b) Modal distributions of the TM cladding mode and TM00, TE10, and TE00 core modes at 1550 nm.
    Fig. 2. Phase-matching condition and modal distributions. (a) Grating period Λ for momentum compensation at different wavelengths. (b) Modal distributions of the TM cladding mode and TM00, TE10, and TE00 core modes at 1550 nm.
    Design for TM00 coupling at 1550 nm. (a) The conversion efficiency along with the propagation at the period of 4.041 µm and the wavelength of 1550 nm. (b) Conversion spectrum at the position of 18Λ. (c) Efficiency spectra of conversions from TE cladding to TE00 and TM cladding to TM00 at the position of 18Λ. (d) The conversion efficiency evolution of TM00 at different wavelengths. Electric field evolution of the TM cladding mode in (e) x–z and (f) y–z planes.
    Fig. 3. Design for TM00 coupling at 1550 nm. (a) The conversion efficiency along with the propagation at the period of 4.041 µm and the wavelength of 1550 nm. (b) Conversion spectrum at the position of 18Λ. (c) Efficiency spectra of conversions from TE cladding to TE00 and TM cladding to TM00 at the position of 18Λ. (d) The conversion efficiency evolution of TM00 at different wavelengths. Electric field evolution of the TM cladding mode in (e) x–z and (f) y–z planes.
    Design for TE10 coupling at 1550 nm. (a) The conversion efficiency along with the propagation at the period of 3.875 µm and the wavelength of 1550 nm. (b) Conversion spectrum at the position of 75Λ. (c) The conversion efficiency evolution of TE10 at different wavelengths. Electric field evolution of the TM cladding mode in (d) x–z and (e) y–z planes.
    Fig. 4. Design for TE10 coupling at 1550 nm. (a) The conversion efficiency along with the propagation at the period of 3.875 µm and the wavelength of 1550 nm. (b) Conversion spectrum at the position of 75Λ. (c) The conversion efficiency evolution of TE10 at different wavelengths. Electric field evolution of the TM cladding mode in (d) x–z and (e) y–z planes.
    Conversion spectra at three typical grating periods Λ. (a) TM00 mode. (b) TE10 mode.
    Fig. 5. Conversion spectra at three typical grating periods Λ. (a) TM00 mode. (b) TE10 mode.
    Schematic of the LNOI edge coupler with asymmetric cladding grating. Top panel: 3D schematic structure. Bottom panel: cross-sections at different positions.
    Fig. 6. Schematic of the LNOI edge coupler with asymmetric cladding grating. Top panel: 3D schematic structure. Bottom panel: cross-sections at different positions.
    Design for TE00 coupling at 1550 nm. (a) Conversion efficiency along with the propagation at the period of 3.047 µm and the wavelength of 1550 nm. (b) Conversion spectrum at the position of 635Λ.
    Fig. 7. Design for TE00 coupling at 1550 nm. (a) Conversion efficiency along with the propagation at the period of 3.047 µm and the wavelength of 1550 nm. (b) Conversion spectrum at the position of 635Λ.
    Conversion spectra at different grating periods Λ for TE00 mode.
    Fig. 8. Conversion spectra at different grating periods Λ for TE00 mode.
    Pengfei Fan, Xiaotian Zhang, Chi Zhang, Shanshan Cheng, Xiao-Hui Tian, Kunpeng Jia, Hua-Ying Liu, Shining Zhu, Zhenda Xie, "Mode-selective edge coupler with cladding grating for a lithium-niobate-on-insulator waveguide," Chin. Opt. Lett. 23, 013603 (2025)
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