  We report a direct experimental observation and provide a theory of the
distribution of trajectories along which a fluctuating system moves over a
potential barrier in escape from a metastable state. The experimental results
are obtained for a semiconductor laser with optical feedback. The distribution
of paths displays a distinct peak, which shows how the escaping system is most
likely to move. We argue that the specific features of this distribution may
give an insight into the nature of dropout events in lasers.
