Bistability of quasi periodicity and period doubling in a delay-induced system

Sustained periodic relaxation oscillations (soft mode) and periodic spiking oscillations (hard mode) leading to chaotic oscillations with different bifurcation situations are found to coexist in lasers with incoherent delayed feedback that can be modeled by particle motion in a Toda-like potential with retarded interaction. Bistability of the soft-mode attractor (quasi periodicity) and the hard-mode attractor (period doubling) and their combined attraction are predicted theoretically. (C) 1999 Optical Society of America [S0740-3224(99)01012-7].