FIBRE LASER SOURCE OF DUAL-WAVELENGTH FEMTOSECOND PULSES

Mode-locked erbium-doped fibre soliton lasers offer a range of desirable properties e.g. tunability and high pulse quality that make them suitable for applications in future nonlinear transmission and computation systems [1-3]. In particular, energy quantization effects caused by the soliton regime of operation of such lasers results in excellent individual pulse parameter stability with regard to pump power fluctuations. This feature is a result of the specific output of fibre soliton lasers, which consists of a number of soliton pulses and a non-soliton component. The output pulse parameters i.e. duration and energy are fixed by the cavity design. The number of circulating pulses is defined by the ratio of the average intracavity intensity to average soliton intensity. Generally this ratio is not an integer, causing the formation of a non-soliton component which plays the role of an energy buffer. Any excess stored intracavity energy (caused, for example, by small fluctuations of pump power) leads to changes in the non-soliton component leaving the parameters of the solitons largely unaltered. This excellent pulse amplitude stability allows complex, amplitude-sensitive nonlinear processing to be investigated such as that reported here.