Lightwave transmission system having remotely pumped quasi- distributed amplifying fibers

摘要

Near uniform optical amplification is achieved in a lightwave transmission system in which a plurality of short lengths of rare earth doped silica-based fibers and a corresponding plurality of long lengths of substantially undoped silica-based fibers are interleaved to form a fiber span having alternating sections of compensated (moderate gain) and uncompensated lightwave transmission media. Pumping of the amplifying fiber sections is performed remotely from either end of the fiber span. Bidirectional pumping, that is, pumping from each end of the fiber span, enhances the uniformity of the optical amplification for signals over the entire span. Amplifying fiber section lengths are variable in substantially inverse proportion to dopant concentration within the particular section.