OPTICAL TRANSMISSION SYSTEM HAVING CASCADED RAMAN AMPLIFIERSWHICH EACH HAVE A NUMBER OF PUMP SOURCES

摘要

An optical transmission system for wavelength-division multiplex (WDM) signals having cascaded Raman amplifiers (V 1,...,V N) has a number of pump sources (LD i l,...,LD i m) (i=1...N) for each Raman amplifier, each having different pump wavelengths sets (.lambda.1,..., .lambda.i m) (i=1....N) from one pump source to another pump source. This results in a flat gain spectrum for all the channels in a WDM transmission signal.