Entraining power-dropout events in an external-cavity semiconductor laser using weak modulation of the injection current

Abstract

Abstract-We measure experimentally the effects of injection current modulation on the statistical distribution of time intervals between power-dropout events occuring in an external-cavity semiconductor laser operating in the low-frequency fluctuation regime. These statistical distributions are sensitive indicators of the presence of pump current modulation. Under most circumstances, we find that weak low-frequency (in the vicinity of 19 MHz) modulation of the current causes the dropouts to occur preferentially at intervals that are integral multiples of the modulation period. The dropout events can be entrained by the periodic perturbations when the modulation amplitude is large (peak-to-peak amplitude 8% of the dc injection current). We conjecture that modulation induces a dropout when the modulation frequency is equal to the difference in frequency between a mode of the extended cavity laser and its adjacent antimode. We also find that the statistical distribution of the dropout events is unaffected by the periodic perturbations when the modulation frequency is equal to the free spectral range of the external cavity. Numerical simulations of the extended-cavity laser display qualitatively similar behavior. The relationship of these phenomena to stochastic resonance is discussed and a possible use of the modulated laser dynamics for chaos communication is described.

Self-organized pore formation and open-loop control in semiconductor etching

“…Counterintuitively, this is possible even by nonresonant perturbations [21]. The more straightforward approach is by resonant parametric perturbations [22,23,24,25,26,27,28] which in the simplest case is a weak sinusoidal signal, but can be any periodic signal. Which orbits can be stabilized by which signals in general can be investigated only if an explicit model of the system is given.…”

Experimental and numerical study of the symbolic dynamics of a modulated external-cavity semiconductor laser

“…While the LK model has been shown to adequately reproduce the main statistical features of the LFF dynamics, such as the IDI distribution with and without modulation [19,29,30], it has also been shown that the LFFs are noise sustained in the LK model [23,24] (i.e., the LFFs are a transient dynamics that dies out when the trajectory finds a stable cavity mode, in deterministic simulations of the LK model). Therefore, it is remarkable that, in spite of the fact that the inclusion of noise is required for simulating sustained LFFs, the model adequately reproduces the symbolic dynamics, and in particular, the correlations present in the sequence of dropouts, and how they vary with the modulation amplitude.…”

“…In the LFF regime, the laser output intensity displays irregular, apparently random and sudden, dropouts. In particular, the LFF dynamics has been studied in detail when the laser current is periodically modulated [26,27], not only because the LFFs can be controlled via current modulation [28], but also, from a complex systems perspective, because the interplay of nonlinearity, noise, periodic forcing and delayed feedback leads to entrainment and synchronization [29,30], providing a controllable experimental setup for studying these phenomena. In addition, because the LFF dynamics is excitable, the influence of external forcing has also attracted attention from the point of view of improving our understanding of how excitable systems respond to external signals to encode information [31][32][33][34][35].…”

“…In this paper, we use a symbolic method of time-series analysis, referred to as ordinal analysis [1], to study the transition from the LFF dynamics of the unmodulated laser, in which the dropouts are highly stochastic and reveal only weak signatures of an underlying deterministic attractor [6], to the modulated LFF dynamics, which consists of more regular dropouts, with a periodicity that is related to external forcing period [29]. For increasing modulation amplitude there is a gradual transition from mainly stochastic to mainly deterministic behavior, and our goal is to identify in this transition characteristic features which are fingerprints of the underlying topology of the phase space of the system.…”

Nonlinear dynamics of a laser diode with optical feedback systems subject to modulation

“…Previous studies have demonstrated that introducing strong optical feedback into a frequency-modulated (direct or intracavity EOM) diode laser can enhance the modulation bandwidth [11]- [14], induce modal instabilities [14]- [17], produce mode-locked output pulses [18]- [23], frequency-locked states [24], low-frequency fluctuations [25], [26], and quasi-periodic [24] and chaotic output power [27], depending on the system operating parameters. No single study has considered the full range of parameters over which all of these states are observed.…”