Fabrication-constrained inverse design and demonstration of high-performance grating couplers

【摘要】 A high-performance grating coupler(GC) operating at a wavelength of 1550 nm is proposed by utilizing the adjoint-based inverse design algorithm on a 220 nm silicon-on-insulator(SOI) substrate. The grating scheme offers several advantages,including simple structure, large minimum feature size(MFS), manufacturing friendliness, support for large-scale production and multi-project wafer (MPW) runs, etc., while simultaneously maintaining exceptional coupling performance and fabrication tolerance. The design process incorporates various fabrication constraints to satisfy the specifications of different foundry processes. The optimized GC demonstrates excellent coupling performance and 3 d B bandwidth within the MFS range of 60 to 180 nm. The simulated coupling efficiency(CE) of the GC with 130 nm MFS is-1.69 dB, whereas the experimentally measured CE of the fabricated GC using electron beam lithography(EBL) is-2.83 dB. Notably, the experimental CE of the GC with 180 nm MFS fabricated using 248 nm deep ultraviolet(DUV) lithography is-2.77 dB, representing the highest experimental CE ever reported for a single-layer etching C-Band GC supported by MPW runs fabricated on 220 nm SOI without utilizing any back reflector, multi-etch layer, or overlay. The manufacturing outcomes of the same GC structure employing different manufacturing processes are discussed and analyzed, providing valuable insights for the fabrication of silicon photonics devices.更多还原

【Abstract】 A high-performance grating coupler(GC) operating at a wavelength of 1550 nm is proposed by utilizing the adjoint-based inverse design algorithm on a 220 nm silicon-on-insulator(SOI) substrate. The grating scheme offers several advantages,including simple structure, large minimum feature size(MFS), manufacturing friendliness, support for large-scale production and multi-project wafer(MPW) runs, etc., while simultaneously maintaining exceptional coupling performance and fabrication tolerance. The design process incorporates various fabrication constraints to satisfy the specifications of different foundry processes. The optimized GC demonstrates excellent coupling performance and 3 d B bandwidth within the MFS range of 60 to 180 nm. The simulated coupling efficiency(CE) of the GC with 130 nm MFS is-1.69 dB, whereas the experimentally measured CE of the fabricated GC using electron beam lithography(EBL) is-2.83 dB. Notably, the experimental CE of the GC with 180 nm MFS fabricated using 248 nm deep ultraviolet(DUV) lithography is-2.77 dB, representing the highest experimental CE ever reported for a single-layer etching C-Band GC supported by MPW runs fabricated on 220 nm SOI without utilizing any back reflector, multi-etch layer, or overlay. The manufacturing outcomes of the same GC structure employing different manufacturing processes are discussed and analyzed, providing valuable insights for the fabrication of silicon photonics devices.更多还原