Extreme Events in Quantum Cascade Lasers Enable an Optical Neuron System
upstart writes in with an IRC submission:
Recently, extreme events have been observed in quantum cascade lasers, as reported by researchers from Telecom Paris (France) in collaboration with UC Los Angeles (USA) and TU Darmstad (Germany). The giant pulses that characterize these extreme events can contribute the sudden, sharp bursts necessary for communication in neuromorphic systems inspired by the brain's powerful computational abilities. Based on a quantum cascade laser (QCL) emitting mid-infrared light, the researchers developed a basic optical neuron system operating 10,000* faster than biological neurons. Their report is published in Advanced Photonics.
Olivier Spitz, Telecom Paris research fellow and first author on the paper, notes that the giant pulses in QCLs can be triggered successfully by adding a "pulse-up excitation," a short-time small-amplitude increase of bias current. Senior author Frederic Grillot, Professor at Telecom Paris and the University of New Mexico, explains that this triggering ability is of paramount importance for applications such as optical neuron-like systems, which require optical bursts to be triggered in response to a perturbation.
The team's optical neuron system demonstrates behaviors like those observed in biological neurons, such as thresholding, phasic spiking, and tonic spiking. Fine tuning of modulation and frequency allows control of time intervals between spikes. Grillot explains, "The neuromorphic system requires a strong, super-threshold stimulus for the system to fire a spiking response, whereas phasic and tonic spiking correspond to single or continuous spike firing following the arrival of a stimulus." To replicate the various biological neuronal responses, interruption of regular successions of bursts corresponding to neuronal activity is also required.
Journal Reference:
Olivier Spitz, Jiagui Wu, Andreas Herdt, et al. Extreme events in quantum cascade lasers [open], Advanced Photonics (DOI: 10.1117/1.AP.2.6.066001)
Read more of this story at SoylentNews.