Single-mode optical waveguide fabricated by oxidization of selectively doped titanium porous silicon

Metal-organic compound molecules were selectively doped into the larger pores of a two-layered porous silicon (PS) which had different pore sizes. PS with a graded pore-size distribution was area-selectively formed by utilizing a thin film mask. Titanium-organic compound molecules were doped into the larger pores and the PS was oxidized to form an optical waveguide. Single-mode transmission of 1.55 μm wavelength laser light was successfully observed.