A systematic study of the temporal evolution and of the power spectrum of the output intensity produced by a hybrid bistable system with a delay in the feedback loop has shown that self-pulsing and chaotic oscillations are the result of the nonlinear coupling among an infinite number of modes of the linearized system. The main qualitative differences observed both experimentally and in computer simulations between short-and long-delay-time regimes are caused by the emergence of progressively more unstable modes as the delay of the feedback is made larger. The fairly abrupt changes in the temporal patterns, which in earlier numerical studies havebeen interpreted as periodicity windows are, instead, the result of frequency locking among a large number of modes of the system. From this work we conclude that the short-and long-delay-time regimes do not differ fundamentally from one another, and can easily be described in terms of a common analysis.