An integrated circuit may include at least one active optical device and a
waveguide coupled thereto. The waveguide may include a superlattice
including a plurality of stacked groups of layers. Each group of layers
of the superlattice may include a plurality of stacked base semiconductor
monolayers defining a base semiconductor portion and an energy
band-modifying layer thereon. The energy-band modifying layer may include
at least one non-semiconductor monolayer constrained within a crystal
lattice of adjacent base semiconductor portions.