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Chaotic instabilities in modulated external-cavity semiconductor lasers

Chaotic stability of external cavity semiconductor laser under modulation is examined both theoretically and experimentally. When the modulation frequency is detuned below the cavity resonant frequency, the simulations show a two-frequency to three-frequency route to chaos, as depicted by the power spectrum and time series of the laser emission at different stages of detuning. This agrees with experimental observations of 1.3 micrometer wavelength distributed feedback (DFB) laser and ridge waveguide (RW) InGaAsP laser. The phase-space attractor of both DFB and RW lasers have well-defined structures at broadband chaotic state, which signifies the presence of dynamical determinism in this state.