Picosecond soliton transmission by use of concatenated gain-distributed nonlinear amplifying fiber loop mirrors

Stable picosecond soliton transmission is demonstrated numerically by use of concatenated gain-distributed nonlinear amplifying fiber loop mirrors (NALMs). We show that, as compared with previous soliton transmission schemes that use conventional NALMs or nonlinear optical loop mirror and amplifier combinations, the present scheme permits a significant increase of loop-mirror (amplifier) spacing. The broad switching window of the present device and the high-quality pulses switched from it provide a reasonable stability range for soliton transmission. We also show that a soliton self-frequency shift can be suppressed by the gain-dispersion effect in the amplifying fiber loop and that soliton-soliton interactions can be partially reduced by using lowly dispersive transmission fibers.