Loss reduction of polymer thin-film optical waveguides

Abstract

Polymer thin films have become a major part of optical integrated circuits in the last two decades. Polymer-based optical waveguides can be easily fabricated by deposition of a polymer solution on a substrate by spin-coating. Under proper conditions, the deposited polymer films exhibit excellent optical properties. Loss quality is an important characteristic of optical waveguides, which dictates the size of the integration of the optical circuits or, in an extreme case, the applicability of the structure. A large part of the optical loss in thin-film waveguides is due to the scattering of the optical wave at the film interfaces with its substrate and cladding. The optimized processing of polymer solutions, which was mentioned earlier, results in a uniform interface at the cladding and reduces this loss. To minimize the scattering loss, other steps can be taken after the polymer film has been deposited.