ROBUST OPERATION OF A DUAL-CORE FIBER RING LASER

A passively mode-locked dual-core fiber ring laser, similar to that fi rst proposed by Winful and Walton [Opt. Lett. 17, 1688 (1992)], is num erically simulated, incorporating losses and higher-order effects. Ult rashort hyperbolic secantlike pulses with negligible chirp are generat ed by this laser. The laser operation is robust but not self-starting; lasing action is found even when stimulated Raman scattering and chan ges in the cavity length are included. The pulse amplitude, phase, and pulse spectrum are discussed. (C) 1995 Optical Society of America