  Loop Quantum Gravity is a formalism for describing the quantum mechanics of
the gravitational field based on the canonical quantization of General
Relativity. The most important result of LQG is that geometric quantities such
as area and volume are not arbitrary but are quantized in terms of a minimum
length. In this paper we investigate the effect of a minimum length in wave
propagation. We find that the minimum length, combined with the constancy of
the speed of light, induces a quantization of the energy of a gravitational
wave.
