In optical waveguide technology, the PCVD process, Plasma Activated Chemical Vapor Deposition, a chemical vapor deposition process, is used as a manufacturing process for graded-index optical waveguides
. In the PCVD manufacturing process, individual layers are vapor deposited onto a glass tube using a plasma-enhanced vacuum that causes chemical reactions. In this way, a glass fiber with almost ideal gradient characteristics is produced. Other manufacturing processes for optical fibers are Modified Chemical Vapor Deposition (MCVD) and Outside Vapor Deposition (OVD).