SIGNAL IMPROVEMENT EFFECT IN O E-E/O CONVERSION USING AN ELECTROABSORPTION (EA) MODULATOR/

O/E-E/O conversion using an electro-absorption (EA) modulator is descr ibed from the viewpoint of noise transfer characteristics, where input optical signals are converted to electrical signals and the EA modula tor is driven by the inversely amplified electrical signals. A thresho ld property in the EA modulation characteristic suppresses signal fluc tuation in the input ''on''-state, provided that the ''on''-level volt age supplied to the modulator exceeds a threshold. Experiments in whic h amplifier ASE light was intentionally imposed on the signal light sh owed improvement in allowable ASE level, and confirmed the noise suppr ession effect.