Disclosed is an optical switching apparatus comprising means for converting serial optical or electrical signals into parallel signals in a time division mode, first and second time division switch groups and a space division switch group for cross connecting the signal of the optical or electrical signals,...http://www.google.com/patents/US5121381?utm_source=gb-gplus-sharePatent US5121381 - Optical switching apparatus for digital signal cross connection and method of interswitch optical transmission of digital signals
