Experimental Spreading and Despreading of the Optical Spectrum.

We report on an experimental realization of Direct-Sequence spreading and despreading of the optical spectrum using off- the-shelf electro-optic modulators. This capability is required to implement a fiber-optic network originally devised by G. J. Forschini and G. Vannucci. The network exploits spread spectrum techniques on the electromagnetic spectrum, together with coherent signal detection, to accommodate a very large number of simultaneous users, for a total throughput measured in hundreds of Gbit/sec. The excellent results obtained in this experiment provide confidence that a network built around this idea would perform according to theoretical calculations. Coherent spectral spreading and despreading is thus established as a promising communication technique for fiber-optic-systems.