Fabrication of large-core, high-Δ optical waveguides in polymers

The realization of polymer optical waveguides that have a large core size and high refractive-index difference (LCHD) Δ transmission characteristics is presented. A fabrication procedure for the waveguide based on vertical dip coating and reactive ion etching has been studied. To achieve the lower propagation loss, this procedure includes two original techniques, i.e., the lamination of thick polymer films and sidewall flattening. With these techniques, Δ of 5.4% and a 80 µm × 83 µm core polymer waveguide with 1.4-dB/cm propagation loss were achieved at 680 nm. The LCHD polymer waveguides are useful for practical power-transmission devices.