Abstract

It is well known that the propagation of light pulses in optical fiber under conditions of anomalous dispersion leads to the formation of bright solitons. In this contribution we report on an experiment in which not a single soliton but rather a whole ensemble of solitons is created. The experiment is straightforward: A train of picosecond pulses from a modelocked laser is launched into a piece of fiber. The fiber forms a ring resonator; its round trip time is adjusted to be synchronous with the repetition time of the laser pulses. Thus there is interference between both contributions to the fiber input light on every round trip. In combination with pulse shaping in the fiber due to dispersion and Kerr nonlinearity, femtosecond substructure in the picosecond pulses is created. This substructure, for the case of anomalous dispersion, has been identified as an ensemble of bright solitons [1]. Mutual interaction leads to constant relative motion of all solitons in the ensemble so that the impression of a gas of particles is created (hence the name ‘soliton gas’ [1]), but under certain conditions (low drive power), the solitons also form a regular array [2]. The soliton gas is a unique test bed for the study of soliton interactions.

© 1998 Optical Society of America