Excitable-like chaotic pulses in the bounded-phase regime of an opto-rf oscillator

Abstract

We report theoretical and experimental evidence of chaotic pulses with excitable-like properties in an opto-radiofrequency oscillator based on a self-injected dual-frequency laser. The chaotic attractor involved in the dynamics produces pulses that, albeit chaotic, are quite regular: They all have similar amplitudes, and are almost periodic in time. Thanks to these features, the system displays properties that are similar to those of excitable systems. In particular, the pulses exhibit a threshold-like response, of well-defined amplitude, to perturbations, and it appears possible to define a refractory time. At variance with excitability in injected lasers, here the excitable-like pulses are not accompanied by phase slips.

Delay-induced instability in phase-locked dual-polarization distributed-feedback fiber lasers

“…The injection process is accounted for by two parameters: the detuning ∆ and the injection strength Γ. The assumptions and approximations leading to this model are described in more detail in [14,15] and references therein. With respect to the equations written in [14,15], two important parameters complete the model: The equations contain the phase-amplitude coupling α and the delay τ associated with the propagation time in the fibered feedback loop.…”

“…Frequency-shifted feedback (FSF) was originally introduced to stabilize dual-frequency bulk solid-state lasers [11,12]. It fostered further developments in our group, leading to the discovery of original boundedphase [13,14], excitablelike [15], or intensity-chaotic frequency-locked [16] regimes. Other studies involved integrated pairs of semiconductor lasers [17,18], but the case of fiber lasers was left open.…”

Triple point of synchronization, phase singularity, and excitability along the transition between unbounded and bounded phase oscillations in a forced nonlinear oscillator

“…This regime is usually referred to as phase trapping [18,19] or frequency locking without phase locking [22]. In recent years, there has been an increasing interest in investigations of injection-locked oscillators discriminating oscillatory regimes with unbounded and bounded phase, especially within the field of optics [24][25][26][27][28][29]. Moreover, injection-locked oscillators constitute an important class of systems where distinct types of excitability are observed [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45].…”

“…In recent years, there has been an increasing interest in investigations of injection-locked oscillators discriminating oscillatory regimes with unbounded and bounded phase, especially within the field of optics [24][25][26][27][28][29]. Moreover, injection-locked oscillators constitute an important class of systems where distinct types of excitability are observed [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. The fact that phase oscillations can be unbounded or bounded affects the geometrical aspects that the excitability phenomenon manifests itself, as we discuss below.…”

“…While Type-I excitability with the phase dynamics exhibiting full 2π rotations is the most common situation appearing in the literature, dynamical scenarios involving experiments and simulations of excitable dynamics not accompanied by 2π phase rotations have been found in delay-coupled lasers [34] and in a dual-mode laser with self-injection [29]. These scenarios of bounded-phase dynamics are not due to the Type-I excitability mechanism.…”