Investigation of the Dynamical Behavior of a High-Power Laser Diode Subject to Stimulated Brillouin Scattering Optical Feedback

In this work, we propose a new scheme of optical feedback using stimulated Brillouin scattering (SBS). A highpower laser diode emitting at 1450 nm stimulates Brillouin backscattering in a 4km-long optical fibre and the back-scattered light is injected back into the laser diode for optical feedback. The experimental results with RF spectrum exhibit clearly the Brillouin frequency shift at 11.46 GHz. Although the frequency shift is very large, the laser diode subject to optical feedback using SBS shows abundant dynamics. RF spectrum maps are also established with respect to the laser drive current. The results are compared with the ones for conventional optical feedback and it is clearly shown that the dynamical behaviours for both the configurations are very different. The investigation with autocorrelation functions reveals that the time-delay signature vanishes completely using the SBS feedback scheme unlike the conventional feedback one

Delay dynamics of neuromorphic optoelectronic nanoscale resonators: Perspectives and applications

With the recent exponential growth of applications using artificial intelligence (AI), the development of efficient and ultrafast brain-like (neuromorphic) systems is crucial for future information and communication technologies. While the implementation of AI systems using computer algorithms of neural networks is emerging rapidly, scientists are just taking the very first steps in the development of the hardware elements of an artificial brain, specifically neuromorphic microchips. In this review article, we present the current state of the art of neuromorphic photonic circuits based on solid-state optoelectronic oscillators formed by nanoscale double barrier quantum well resonant tunneling diodes. We address, both experimentally and theoretically, the key dynamic properties of recently developed artificial solid-state neuron microchips with delayed perturbations and describe their role in the study of neural activity and regenerative memory. This review covers our recent research work on excitable and delay dynamic characteristics of both single and autaptic (delayed) artificial neurons including all-or-none response, spike-based data encoding, storage, signal regeneration and signal healing. Furthermore, the neural responses of these neuromorphic microchips display all the signatures of extended spatio-temporal localized structures (LSs) of light, which are reviewed here in detail. By taking advantage of the dissipative nature of LSs, we demonstrate potential applications in optical data reconfiguration and clock and timing at high-speeds and with short transients. The results reviewed in this article are a key enabler for the development of high-performance optoelectronic devices in future high-speed brain-inspired optical memories and neuromorphic computing. (C) 2017 Author(s).Fundacao para a Ciencia e a Tecnologia (FCT) [UID/Multi/00631/2013]European Structural and Investment Funds (FEEI) through the Competitiveness and Internationalization Operational Program - COMPETE 2020National Funds through FCT [ALG-01-0145-FEDER-016432/POCI-01-0145-FEDER-016432]European Commission under the project iBROW [645369]project COMBINA [TEC2015-65212-C3-3-PAEI/FEDER UE]Ramon y Cajal fellowshipinfo:eu-repo/semantics/publishedVersio

All-Optical Logic Gates and Wavelength Conversion Via the Injection-Locking of a Fabry-Perot Semiconductor Laser

This work investigates the implementation of all-optical wavelength conversion and logic gates based on optical injection locking (OIL). All-optical inverting, NOR, and NAND gates are experimentally demonstrated using two distributed feedback (DFB) lasers, a multi-mode Fabry-Perot laser diode (MMFP-LD), and a optical band-pass filter (BPF). The DFB lasers are externally modulated to represent logic inputs into the cavity of the MMFP-LD slave laser. The master lasers\u27 wavelengths are aligned with the longitudinal modes of the MMFP-LD slave laser and their optical power is used to modulate the injection conditions in the slave laser. The optical BPF is used to select the longitudinal mode that is suppressed or transmitted given the logic state of the injecting master laser signals. When the input signal(s) is (are) in the on state, injection locking, and thus the suppression of the non-injected Fabry-Perot modes, is induced, yielding a dynamic system that can be used to implement photonic logic functions. Additionally, all-optical photonic processing is achieved using the cavity mode shift produced in the injected slave laser under external optical injection. The inverting logic case can also be used as a wavelength converter -- a key component in advanced wavelength-division multiplexing networks. The result of this experimental investigation is a more comprehensive understanding of the locking parameters concerning the injection of multiple lasers into a multi-mode cavity. Attention is placed on the turn-on/turn-off transition dynamics, along with the maximum achievable bit rates. The performance of optical logic computations and wavelength conversion has the potential for ultrafast operation, limited primarily by the photon decay rate in the slave laser