Devices and methods are provided that spatially restrict online communications to persons from a real world meeting. The optical waveguide is a circuit being able to keep radiation light in a certain region and to transmit the radiation light in such a way that the energy flow thereof is guided in parallel with an axis of the channel. The light receiving surface has different refraction angles according to the wavelengths of the input light and demultiplexes the input light wavelength by wavelength. Over successive generations existing solutions are modified, and an identified solution in the population is removed at each successive generation.