Two-way reflector based on two-dimensional sub-wavelength high-index contrast grating on SOI

•The proposed design of two-way reflector on SOI provides high reflectivity.•Normal and oblique/grazing angles of incidence are used.•The same reflector design can be used to make VCSEL mirror and planar waveguide.•It's large reflection bandwidth acts as an advantage for broadband photonic devices.

A two-dimensional (2D) high-index contrast grating (HCG) is proposed as a two-way reflector on Silicon-on-insulator (SOI). The proposed reflector provides high reflectivity over two (practically important) sets of angles of incidence- normal(θ=0°)(θ=0°) and oblique/grazing (θ=80°−85°/90°θ=80°−85°/90°). Analytical model of 2D HCG is presented using improved Fourier modal method. The vertical incidence is useful for application in VCSEL while oblique/grazing incidence can be utilized in high confinement (HCG mirrors based) hollow waveguides and Bragg reflectors. The proposed two-way reflector also exhibits a large reflection bandwidth (around telecom wavelength) which is an advantage for broadband photonic devices.