US Patent 7650049 - Quantum box waveguide modulator

http://www.freepatentsonline.com/7650049.html

This patent is from the Commissariat a l'Energie Atomique and teaches using photonic crystals to modulate the absorption and velocity of optical waves. Claim 1 reads:

1. A modulator comprising:

a waveguide including periodic holes and propagating an electromagnetic wave of given wavelength (λ) with absorption, and further comprising

means adapted to vary an electrical charge population in quantum boxes included in the waveguide so as to modify the residence time of the electromagnetic wave in the waveguide.