EXPERIMENTAL STUDIES ON WAVELENGTH-DIVISION BIDIRECTIONAL OPTICAL AMPLIFIERS USING AN ER(3-DOPED FIBER())

This paper presents a novel structure of an Er3+-doped fiber amplifier capable of bidirectional operation through the wavelength division mu ltiplex method. The idea is to combine an Er3+-doped fiber, pump devic es, optical isolators, and wavelength selective couplers so that two l ightwaves having different wavelengths pass each proper isolator. The suitable structure was determined from experimental studies on several basic amplifier configurations. Optical gains of more than 25 dB were attained in both wavelength regions of 1.533 mum and 1.55 mum. Succes sful bidirectional operation of the amplifier was confirmed by means o f a 2.488-Gbit/s-signal transmission experiment.