Heralded preparation and distillation of entangled light

In this paper, we discuss the heralded preparation of entangled light, using ideas that bring together continuous-variable and discrete-variable approaches. At the center of this discussion are efforts to prepare and distributed entangled light in the presence of noisy, in distillation and filtering schemes that form a part of an instance of a quantum repeater. Such or similar procedures must be at the basis of any optical quantum communication scheme over long distances, such as quantum key distribution in the presence of noise.