Graphene Optical Modulator (IMAGE) University of California - Berkeley Caption This is a schematic illustration of the graphene-based optical modulator. A layer of graphene (black fishnet) is placed on top of a silicon waveguide (blue), which is used as an optical fiber to guide light. Electrical signals are sent in from the side of the graphene to alter the amount of photons the graphene absorbs. Credit Graphic by Ming Liu, UC Berkeley Usage Restrictions Creditline: Ming Liu, UC Berkeley License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.