A novel design of bi-directional silica-based erbium-doped fibre amplifierfor broadband WDM transmissions

A new method for a broadband amplification based on erbium-doped fibre ampl ifier was developed using only a single laser diode pumped at 1480 nm. A du al-stage amplifier was employed where the first stage provides simultaneous bi-directional amplification of conventional- and long-band signals. The u tilisation of unused amplified spontaneous emission and remnant pump power from the first stage enables realisation of high gain for the long-band sig nals in the second stage. Amplification of wavelength division multiplexing systems (two and four channels) was successfully demonstrated with an aver age gain of 22 dB and a noise figure less than 7 dB. (C) 2001 Elsevier Scie nce B.V. All rights reserved.