Noise-induced on–off intermittency in mutually coupled semiconductor lasers

Intermittent switches between low-frequency fluctuations and steady-state emission are experimentally observed in two bidirectionally coupled semiconductor lasers subject to common Gaussian noise applied to the laser pump currents. The time series analysis reveals power-law scalings typical for on–off intermittency near its onset, with critical exponents of −1 for the mean turbulent length versus noise intensity and −3/2 for probability distribution of laminar phases versus the laminar length. The same −1 power-law scaling is found by the power spectrum analysis for the signal-to-noise ratio versus the noise intensity.