Optical systems of the present invention include an add/drop device and/or cross-connect device, which is reconfigurable to add and drop signal wavelengths between one or more transmission paths. The add/drop device includes a first selective element configurable to pass a first group of signal wavelengths...http://www.google.com/patents/US6934473?utm_source=gb-gplus-sharePatent US6934473 - Optical systems including add drop devices and methods
