title: High-performance and compact binary blazed grating coupler based on an asymmetric subgrating structure and vertical coupling.
abstract: A high-performance and compact fiber-to-waveguide binary blazed subwavelength grating coupler was designed based on silicon-on-insulator. By the appropriate choice of waveguide/grating parameters, including thicknesses, periods, height, and fill factor, to optimize the mode matching, a relatively high coupling efficiency was obtained for the fiber and waveguide interface. Moreover, perfectly vertical fiber coupling is achieved by using an asymmetric subgrating structure in which a period consists of two subgratings with identical etching height and different widths. Coupling efficiency as high as 69% at a wavelength of 1.52 μm and 65% at a wavelength of 1.55 μm is calculated. Simultaneously, the 1 dB wavelength bandwidth is around 80 nm. The coupling efficiency can reach up to 80% or so if Bragg reflector layers are added. Finally, the device layout is simple, feasible, one-step etched, and compatible with standard complementary metal-oxide semiconductor technology processing.
authors.affiliation: State Key Laboratory on Advanced Optical Communication Systems and Networks, Peking University, Beijing 100871, China.
authors.forename: Junbo
authors.initials: J
authors.lastname: Yang
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Zhou
authors.forename: Honghui
authors.initials: H
authors.lastname: Jia
authors.forename: Xueao
authors.initials: X
authors.lastname: Zhang
authors.forename: ShiQiao
authors.initials: S
authors.lastname: Qin