TL;DR: In this paper, a monolithically-integrated optical waveguide device formed on a substantially planar substrate was proposed. But the design of the waveguide was not discussed.
Abstract: The invention provides a monolithically-integrated optical waveguide device formed on a substantially planar substrate. Two types of optical components are formed on the same substrate: at least one first type of waveguide device component having a silica-based core; and at least one second type of waveguide device component having a substantially non-silica-based core. The first and second types of waveguide device components are in optical communication with each other and are arranged to perform different optical signal processing functions. Examples of functions which can be performed by the first type of component include multiplexing, de-multiplexing, gain equalisation, or optical attenuation. Examples of functions which can be performed by the second type of component include optical power modulation, optical amplification, and light emission.