Crystalline organic semiconductor optical directional couplers and switches using an index-matching layer

A directional coupler using crystalline organic semiconductor waveguides grown by the vacuum process of organic molecular beam deposition is demonstrated. An index-matching layer placed between two coupled waveguides separated by a 1 mu m gap greatly increases the coupling coefficient, significantly decreasing the coupling length and making the device very compact. Switching of 1.06 mu m wavelength light from one guide to another in the coupler has been observed by pumping the surface of one guide in the coupling region with 0.514 mu m.>