Observation of a Pomeau-Manneville intermittent route to chaos in a nonlinear oscillator

For a driven nonlinear semiconductor oscillator which shows a period-doubling pitchfork bifurcation route to chaos, we report an additional route to chaos: the Pomeau-Manneville intermittency route, characterized by a periodic (laminar) phase interrupted by bursts of aperiodic behavior. This occurs near a tangent bifurcation as the system driving parameter is reduced by ε from the threshold value for a periodic window. Data are presented for the dependence of the average laminar length $〈l〉$ on ε, and also on additive random noise voltage. The results are in reasonable agreement with the intermittency theory of Hirsch, Huberman, and Scalapino. The distribution $P(l)$ is also reported.