Abstract

Tine performance of soliton transmission systems is compromised by less than transform-limited input pulses; in particular, the energy shed by initially chirped pulses as so-called dispersive-wave radiation can add significantly to the noise. Although external cavity semiconductor lasers can produce trains of pulses at the required GHz rates, their pulses are chirped by refractive-index changes that always accompany the gain modulation. Actively mode-locked erbium fiber ring lasers can produce transform-limited pulses,¹ but must use harmonic mode-locking to achieve GHz repetition rates. Modelocking at high harmonics readily leads to pulse amplitude variations and instability unless unwanted modes of the ring can be suppressed.

© 1992 Optical Society of America