Using spread-spectrum in a high-capacity fiber-optic local network.

We propose a local fiber-optic communications network capable of supporting tens of thousands of simultaneous users, each requiring of the order of 10 Mbit/sec continuous data rate. The system uses coherent optical techniques to exploit the vase bandwidth offered by single-mode optical fibers (tens of thousands of GHz). A spread-spectrum technique is used to circumvent the problems caused by the instabilities of present-day semiconductor lasers. These include difficulty in reliably setting a laser's frequency with an accuracy better than several hundred GHz and phase noise in the laser output, which would otherwise result in excessive amounts of interference among the various users.