IBM’s optical modulator uses “silicon nanophotonic waveguides,” to control the flow of light on a silicon chip. The waveguides are made of tiny silicon strips (marked by purple color) with dimensions 200 times smaller than the diameter of a human hair, in a silicon-on-insulator (SOI) wafer.
Light is strongly confined within the silicon nanophotonic waveguide as shown by the colored concentric ellipses overlaid with the waveguide image. The strong confinement of light allows the IBM modulator to be dramatically scaled down in size.
