Publicaties
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Monostable multivibrators as novel artificial neurons Vrije Universiteit Brussel
Retriggerable and non-retriggerable monostable multivibrators are simple timers with a single characteristic, their period. Motivated by the fact that monostable multivibrators are implementable in large quantities as counters in digital programmable hardware, we set out to investigate their applicability as building blocks of artificial neural networks. Wederive the nonlinear input-output firing rate relations for single multivibrator neurons ...
Bistability in a system of two species interacting through mutualism as well as competition Vrije Universiteit Brussel KU Leuven
We theoretically study the dynamics of two interacting microbial species in the chemostat. These species are competitors for a common resource, as well as mutualists due to cross-feeding. In line with previous studies (Assaneo, et al., 2013; Holland, et al., 2010; Iwata, et al., 2011), we demonstrate that this system has a rich repertoire of dynamical behavior, including bistability. Standard Lotka-Volterra equations are not capable to describe ...
Random number generator based on an integrated laser with on-chip optical feedback Vrije Universiteit Brussel
We discuss the design and testing of a laser integrated with a long on-chip optical feedback section. The device and feedback section have been fabricated on a generic photonic integration platform using only standard building blocks. We have been able to integrate a 10 cm feedback length on a footprint of 5.5 mm2. By controlling the amount of feedback, we achieve chaotic dynamics in the long-cavity regime and show that the resulting dynamics is ...
Speckle reduction in laser projection using microlens-array screens Vrije Universiteit Brussel
We report on a novel speckle reduction scheme using microlens arrays as screen material for application in laser-based projection systems. The scheme is based on properly adjusting the coherence properties on the screen: when the coherence area on the microlens-array screen is smaller than the microlens footprint, there is no interference between the fields emitted by the di erent microlenses and as a result no speckle is formed. We measured ...
Stability of steady and periodic states through the bifurcation bridge mechanism in semiconductor ring lasers subject to optical feedback Vrije Universiteit Brussel
With the development of new applications using semiconductor ring lasers (SRLs)
subject to optical feedback, the stability properties of their outputs becomes a crucial issue. We
propose a systematic bifurcation analysis in order to properly identify the best parameter ranges
for either steady or self-pulsating periodic regimes. Unlike conventional semiconductor lasers,
we show that SRLs exhibit both types of outputs ...
subject to optical feedback, the stability properties of their outputs becomes a crucial issue. We
propose a systematic bifurcation analysis in order to properly identify the best parameter ranges
for either steady or self-pulsating periodic regimes. Unlike conventional semiconductor lasers,
we show that SRLs exhibit both types of outputs ...
Parallel processing using an optical delay-based reservoir computer Vrije Universiteit Brussel
Delay systems subject to delayed optical feedback have recently shown great potential in solving computationally hard tasks. By implementing a neuro-inspired computational scheme relying on the transient response to optical data injection, high processing speeds have been demonstrated. However, reservoir computing systems based on delay dynamics discussed in the literature are designed by coupling many different stand-alone components which lead ...
Semiconductor Ring Lasers Subject to Both On-Chip Filtered Optical Feedback and External Conventional Optical Feedback Vrije Universiteit Brussel
Dynamics of quantum cascade lasers: numerics Vrije Universiteit Brussel
Since the original demonstration of terahertz quantum-cascade lasers (QCLs), the performance of these devices has shown rapid improvement. QCLs can now deliver milliwatts or more of continuous-wave radiation throughout the terahertz frequency range (300 GHz to 10 THz). Therefore, QCLs have become widely used in various applications such as spectroscopy, metrology or free-space telecommunications. For many of these applications there is a need ...