Atlanta Fiber System Experiment: Practical 45-Mb/s Regenerator for Lightwave Transmission

An optical regenerator* is essentially a digital regenerator with optoelectronic transducers at the input and output. The transducers used here are an avalanche photodiode and a GaAlAs injection laser. The regenerator includes the usual features of amplification, filtering, automatic gain control, retiming, and regeneration. Some features peculiar to a design for a lightwave transmission system are very high gain and wide dynamic range. Also, the characteristics of the transducers must be stabilized with feedback. The optical regenerator described here is the prototype of a design for a field environment. The intended transmission medium is low-loss graded-index fiber.1-16 The regenerator was initially used in the Atlanta Experiment, a study of a lightwave transmission system in an environment simulating field conditions.2 * A regenerator is a one-way repeater.