Oxide superconductors are classified as ''interstitial'' or ''substitu
tional'' depending on the site of the dopant oxygen which causes super
conductivity. Only substitutional oxide superconductors normally exhib
it photoinduced superconductivity. High-temperature superconductivity
originates with dopant oxygen, as has been demonstrated in BSCCO, wher
e the cuprate planes are insulating, but the Bi-O layers superconduct.