Fiber optic communication method and apparatus providing mode multiplexing and holographic demultiplexing

摘要

In a fiber optic communication system, an acoustooptic modulator operates to provide a coherent light beam that is data encoded in the beam's time domain, for example by intensity modulation of the beam. A spatial light modulator then operates to address encode the beam by modulating the beam in the space domain. The resulting data and address modulated beam possesses the property of orthogonality. This beam is now transmitted to the input of a multimode optical fiber. The speckle pattern that exits the output of the optical fiber also exhibits orthogonality. This output beam is presented to a beam splitter in order to produce two spatially modulated speckle light patterns therefrom. These two beams are then focused onto photorefractive means whereat a hologram is produced. This hologram operates to address decode the beam output of the optical fiber. Detector means now operates to detect the data by receiving the beam as it is diffracted by the hologram. Ring and star interconnect networks are described.