Electrical addressing and temporal tweezing of localized pulses in passively-mode-locked semiconductor lasers

Abstract

We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures (LSs), also called localized pulses, found in passively mode-locked Vertical-Cavity Surface-Emitting Lasers. While short electrical pulses can be used for writing and erasing individual LSs, we demonstrate that a current modulation introduces a temporally evolving parameter landscape allowing to control the position and the dynamics of LSs. We show that the localized pulses drifting speed in this landscape depends almost exclusively on the local parameter value instead of depending on the landscape gradient, as shown in quasi-instantaneous media. This experimental observation is theoretically explained by the causal response time of the semiconductor carriers that occurs on an finite timescale and breaks the parity invariance along the cavity, thus leading to a new paradigm for temporal tweezing of localized pulses. Different modulation waveforms are applied for describing exhaustively this paradigm. Starting from a generic model of passive mode-locking based upon delay differential equations, we deduce the effective equations of motion for these LSs in a time-dependent current landscape.

Spontaneous symmetry breaking and trapping of temporal Kerr cavity solitons by pulsed or amplitude-modulated driving fields

“…Indeed, localized structures are intuitively expected to be attracted towards non-zero parameter gradients only in systems with broken parity symmetry (e.g. in the presence of convection) [42,49,50]. On the other hand, Kerr cavities are well-known to exhibit spontaneous symmetry breaking [38][39][40][41][51][52][53], which could explain the emergence of asymmetric states consisting of CSs trapped at edges of amplitude modulations.…”

Temporal localized structures in optical resonators

“…Writing and erasure of temporal LSs is usually implemented by perturbing the system with an optical pulse injected inside the cavity, as described in Section 2.1. While addressing would be in principle feasible using optical injection, here we take advantage of the fast response of semiconductor media to pumping current modulation and we address LSs by adding electrical pulses to the laser bias [51,52]. This parameter, which is commonly used in optoelectronics for converting an electrical bit stream into an optical one at rates higher than 10 GHz [53], appears to be very convenient for LSs' applications to information processing.…”

“…Similarly, a single localized structure can be erased using a negative bias current pulse bringing locally the system in the region where only the off solution is stable (Figure 3(f)). Addressing operations can be successfully implemented starting from other initial conditions [52], provided that the separation between the writing pulse and preexisting LSs allows for sufficient gain recovery. This latency indicates that, even if the intensity profile of a LS exhibits a temporal width of approximately 10 ps, its effective width is ultimately fixed by the characteristic time of the underlying gain recovery process, which is typically about 1 ns.…”

Bound Pulse Trains in Arrays of Coupled Spatially Extended Dynamical Systems

“…Another scenario occurs in the case of monotonic repulsive interaction when either the pulse tails decay monotonically, or a strong nonlocal repulsive interaction between the pulses is present. In this case the pulses tend to distribute equidistantly in time or space leading to periodic pulse trains [15][16][17][18] which, in contrast to closely packed bound states, exhibit large distances between the consequent pulses.In this Letter we show that even in the case when the pulses in an individual system exhibit strong repulsion, the formation of bound pulse trains can be achieved by arranging several systems in an array with nearestneighbor coupling. As a result, the pulses interact not only within one system, but also with those in the neighboring ones leading to a different balance of attraction and repulsion.…”

“…Another scenario occurs in the case of monotonic repulsive interaction when either the pulse tails decay monotonically, or a strong nonlocal repulsive interaction between the pulses is present. In this case the pulses tend to distribute equidistantly in time or space leading to periodic pulse trains [15][16][17][18] which, in contrast to closely packed bound states, exhibit large distances between the consequent pulses.…”