Robust sequence storage in bistable oscillators

International audienceNanoscale devices, like magnetic tunnel junction, have rich dynamics, including oscillatory ones. Such components may relieve us of the burden of integrating nonlinear equations. We propose a phenomenological model of bistable oscillators and we show that in a network, it achieves robust storage of sequences

Dissipative solitons in pattern-forming nonlinear optical systems : cavity solitons and feedback solitons

Many dissipative optical systems support patterns. Dissipative solitons are generally found where a pattern coexists with a stable unpatterned state. We consider such phenomena in driven optical cavities containing a nonlinear medium (cavity solitons) and rather similar phenomena (feedback solitons) where a driven nonlinear optical medium is in front of a single feedback mirror. The history, theory, experimental status, and potential application of such solitons is reviewed

Regenerative memory in time-delayed neuromorphic photonic resonators

We investigate a photonic regenerative memory based upon a neuromorphic oscillator with a delayed self-feedback (autaptic) connection. We disclose the existence of a unique temporal response characteristic of localized structures enabling an ideal support for bits in an optical buffer memory for storage and reshaping of data information. We link our experimental implementation, based upon a nanoscale nonlinear resonant tunneling diode driving a laser, to the paradigm of neuronal activity, the FitzHugh-Nagumo model with delayed feedback. This proof-of-concept photonic regenerative memory might constitute a building block for a new class of neuron-inspired photonic memories that can handle high bit-rate optical signals

Fundamentals and applications of spatial dissipative solitons in photonic devices : [Chapter 6]

We review the properties of optical spatial dissipative solitons (SDS). These are stable, self‐localized optical excitations sitting on a uniform, or quasi‐uniform, background in a dissipative environment like a nonlinear optical cavity. Indeed, in optics they are often termed “cavity solitons.” We discuss their dynamics and interactions in both ideal and imperfect systems, making comparison with experiments. SDS in lasers offer important advantages for applications. We review candidate schemes and the tremendous recent progress in semiconductor‐based cavity soliton lasers. We examine SDS in periodic structures, and we show how SDS can be quantitatively related to the locking of fronts. We conclude with an assessment of potential applications of SDS in photonics, arguing that best use of their particular features is made by exploiting their mobility, for example in all‐optical delay lines

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

Optical multi-stable operations of coupled lasers

Optical memories are optical bi(multi-)stable systems whose states can be switched all optically. Acting as a fundamental building block for digital optical signal processing, they have received considerable attention. Many types of optical memories have been explored, which all have in common that they are optical storage elements with two states. Multi-stable optical logic building blocks are interesting for applications in telecommunication systems, since they have potential to process a large number of wavelength channels in parallel. In this thesis, we present two types of multi-stable operation of coupled lasers. The first one is based on coupled ring lasers, which share a single active element and a feedback arm. A single ring laser with feedback can be regarded as an oscillator, since the intensity of the lasing light in the lasing cavity is periodically oscillating. When two such oscillators are coupled together, sharing the same active element and the same feedback arm, they synchronize in a common oscillation frequency if their individual oscillation periodicities are close to each other; otherwise they show bistability between the two oscillators. Switching between different stable states can be realized by injecting external light, in this sense, the system act as an optical memory. Moreover, this concept can easily realize multi-state operation, since only one active element is required. An eight-state optical memory is demonstrated. The second type of multi-stable operation of coupled lasers is based on serially interconnected lasers using the principle of gain quenching. The light from the dominant laser suppresses its neighboring lasers through gain saturation, but still receives amplification by the active element of the suppressed lasers, compensating for coupling losses. This light passes through each of the successive lasers, simultaneously suppressing and being amplified. By this mechanism all the other lasers are suppressed. Only one of the lasers can lase at a time, thus the state of the optical memory is determined by the wavelength of the dominant laser, as same as the first type. A five-state optical memory based on this concept is experimentally demonstrated. Moreover, we use the optical memories as a fundamental logic unit to realize sophisticated optical logic. We present an optical shift register that consists of two serially connected optical memories driven by common clock pulses. The concept is demonstrated at an operation speed of 20 kHz, which is limited by the laser cavities implemented by 10 meter long fiber pigtailed components. Furthermore, we cascade the optical shift register and an optical XOR gate to realize an optical pseudorandom number generator based on optical memories

Hybrid PUF Design using Bistable Ring PUF and Chaotic Network

Physical Unclonable Function(PUF) is lightweight hardware that provides affordable security for electronic devices and systems which can eliminate the use of the conventional cryptographic system which uses large area and storage. Among the several models, Bi-stable Ring PUF(BR-PUF) is considered as a secure and efficient PUF model since it has no mathematical model still found. In this thesis, we proposed a modified design called a hybrid model of BR-PUF and a Chaotic network to improve the BR-PUF resilience against machine learning attacks. We experimented with the current modification XOR technique to analyze the uniqueness, reliability and resource consumption. The proposed PUF was implemented on Xilinx Artix 7 FPGA and the PUF metrics were captured and compared with the results of XOR-ed based PUF integration techniques. The lightweight PUF model was achieved with 16% resource reduction when compared to XOR-ed BR PUF with no compromise in PUF quality