Broadband and gain-flattened amplifier composed of a 1.55 µm-band and a 1.58 µm-band Er3+-doped fibre amplifier in a parallel configuration

The authors construct a broadband and gain-flattened Er3+-doped fibre amplifier (EDFA) with a flat amplification bandwidth of 54 nm for wavelength division multiplexed signals. This was achieved by employing a 1.58 µm-band EDFA and a 1.55 µm-band EDFA in a parallel configuration. Excellent flat amplification characteristics were obtained for 1530–1560 nm and 1576–1600 nm signal wavelength regions, with a gain non-uniformity of <1.7 dB and a signal gain of 30 dB.