Distinguishing chaos from noise in an optically bistable system

We propose an operational test for chaos which leads to a straightforward experimental distinction between chaos and noise. The test involves the repeated measurement of the initial transient of a system whose initial condition is fixed. Our method does not require the collection of a time series, which is at best expensive and presently impossible for high-speed optical systems. We have experimentally verified this test with out hybrid optically bistable device. The test is limited to dissipative systems such as occur in optics.