An optical device is provided that includes an active waveguide having a top electrode and a plurality of layers including a gain layer. Configurations are disclosed for the active waveguide to enable amplification of a guided optical wave profile while preserving a shape of a lateral optical intensity profile of the guided optical wave as the guided optical wave is amplified along the waveguide. The top electrode and/or one or more layers of the active optical waveguide may be tailored to provide a tailored optical gain.