A collimation mirror in polymeric planar waveguide formed by reactive ion etching

We fabricated and characterized an integrated optical mirror in a polymeric waveguide. A parabola-shaped cavity is etched in fluorinated polyimide using oxygen reactive ion etching. The vertically etched sidewall of the planar waveguide works as a highly reflecting total-internal-reflection mirror, which collimates a diverging beam from its focus. The estimated mirror insertion loss of the demonstrated device is 2.4 dB or less.