Electrical Addressing and Temporal Tweezing of Localized Pulses in Passively Mode-Locked Semiconductor Lasers

TL;DR

This paper demonstrates how electrical current modulation can precisely control the position and dynamics of localized pulses in passively mode-locked semiconductor lasers, revealing a new paradigm for temporal tweezing based on carrier response times.

Contribution

It introduces a novel method of manipulating localized pulses using current landscapes, supported by experimental and theoretical analysis based on delay differential equations.

Findings

Localized pulses drift dependently on local current values.

Current modulation enables writing, erasing, and repositioning pulses.

Theoretical model explains the causality-based drift behavior.

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.