A novel design for broadband fiber amplifier

A new method for a broadband amplification based on an Er doped fiber amplifier was developed using only a single laser diode pumped at 1480 nm. A dual-stage amplifier was employed where the first stage provides simultaneous bi-directional amplification of conventional- and long-band signals. The utilization of unused amplified spontaneous emission and remnant pump power from the first stage enables realization of high gain for the long-band signals in the second stage. Amplification of wavelength division multiplexing systems (2 and 4 channels) was successfully demonstrated with an average gain of 22 dB and a noise figure less than 7 dB.