Apparatus for communication in a fiberoptic LAN includes a first transmitter of an electromagnetic wave of a first wavelength, a second detector of an electromagnetic wave of a second wavelength, and an optical coupler coupled to the first transmitter, the second detector, and the fiberoptic LAN....http://www.google.de/patents/US5978118?utm_source=gb-gplus-sharePatent US5978118 - Guided optical communication
