In California, Bookham Inc. of San Jose has nonexclusively licensed patents on silicon photonics to Kotura Inc., a Monterey Park supplier of silicon photonic components. The technology covered by the patents involves the fabrication of multifunctional optical silicon chips, and the design and manufacture of such silicon waveguide devices as variable optical attenuators and modulators. Bookham withdrew from the silicon photonics market in 2003.