A method of operating an optical device includes inserting a light signal into a waveguide positioned on a base. A light sensor is positioned on the base and is configured to receive the light signal after the light signal exits from the waveguide. The method also includes elevating the light signal relative to the base before the light signal enters the light sensor. The light signal is elevated such that the light signal enters the light-absorbing medium in a position that is elevated above the position where the light signal would enter the light-absorbing medium if the light-absorbing medium received the entire light signal directly from the waveguide.