Alternate paths to chaos in optical bistability

Alternate paths to chaos are observed experimentally in a hybrid optically bistable system with delayed feedback. The waveforms observed on these alternate paths are the frequency-locked waveforms seen in an earlier experiment which we find to be modified versions of the typical period-doubled waveforms. The transitions between these waveforms are discontinuous and show hysteresis loops. By the introduction of an external locking signal we are able to stabilize waveforms in the neighborhood of the discontinuous transitions. By so doing we show that the transitions among the branches are due to their lack of stability. The transition are thus not strictly first-order nonequilibrium phase transitions, since in that case the branches cease to exist at the transition point.