Thin-film waveguide with lens effect terminal for optical sensing device

We have developed a thin-film optical waveguide, which is capable of condensing light at an input terminal of the waveguide. This effect was achieved by shaping an end of the waveguide with a curvature. The input terminal works as a lens by this curvature. The curvature of the lens is controllable by changing a radius of the terminal. The waveguides are composed of under-cladding, core, and over-cladding layers. All of them have been made of fluorinated polyimides. The lens effect of the waveguide improved the resolution. The resolutions of the waveguides with circular terminal (radii of 500, 800 [μm]) were superior to the one with flat terminal by about 20%.