Abstract

Since its first observation by K. Tai et al., modulational instability (MI) has been used to generate a high repetition-rate soliton-like pulse trains in optical fibers (several THz)¹. In the scalar case. MI only occurs in the anomalous GVD regime and leads to a train of bright solitons. However, in the normal GVD regime, owing to a coupling between two modes. MI can also occur and a train of dark solitons can be generated. In weakly birefringent fibers, coupling between two counter-rotating circular polarizations is a mean to obtain this train of dark solitons². However, polarization instabilities in low-birefringence fibers set a serious limit to the practical implementation of this technique. In this work, we demonstrate that a stable source of gray and dark soliton wave-trains may be achieved by using high-birefringence fibers. MI was induced with a weak anti-Stokes wave polarized along the fast axis of a high-birefringence fiber.

© 1998 IEEE