All-optical neuromorphic binary convolution with a spiking VCSEL neuron for image gradient magnitudes

Abstract

All-optical binary convolution with a photonic spiking vertical-cavity surface-emitting laser (VCSEL) neuron is proposed and demonstrated experimentally for the first time, to the best of our knowledge. Optical inputs, extracted from digital images and temporally encoded using rectangular pulses, are injected in the VCSEL neuron, which delivers the convolution result in the number of fast (<100 ps long) spikes fired. Experimental and numerical results show that binary convolution is achieved successfully with a single spiking VCSEL neuron and that alloptical binary convolution can be used to calculate image gradient magnitudes to detect edge features and separate vertical and horizontal components in source images. We also show that this all-optical spiking binary convolution system is robust to noise and can operate with high-resolution images. Additionally, the proposed system offers important advantages such as ultrafast speed, high-energy efficiency, and simple hardware implementation, highlighting the potentials of spiking photonic VCSEL neurons for high-speed neuromorphic image processing systems and future photonic spiking convolutional neural networks.

Photonic matrix multiplication lights up photonic accelerator and beyond

“…And the microring resonators with PCMs were also demonstrated as effective all-optical activation functions 89 . The active optical devices are also promising candidates for activation functions 144 , 155 – 157 . A reconfigurable photonic activation function was also demonstrated using injection-locked Fabry–Perot semiconductor lasers 155 .…”

“…The neuronlike excitable behavior in a micropillar laser with saturable absorber was experimentally demonstrated by introducing optical perturbations 144 . And the vertical-cavity surface-emitting laser with an embedded saturable absorber was employed as a spiking neuron 156 , 157 . The semiconductor optical amplifiers were also demonstrated for all-optical activation functions 158 – 161 .…”

Photonic neuromorphic computing using vertical cavity semiconductor lasers

“…It is only very recently that the first experimental demonstrators of spike processing systems, with VCSEL neurons for ultrafast neuromorphic photonic computing, have started to emerge [74][75][76][77][78][79] . Using VCSEL spiking neurons, several processing tasks, typical of artificial intelligence (AI) implementations, have been reported (e.g.…”

Ultrafast neuromorphic photonic image processing with a VCSEL neuron

“…Furthermore, theoretical spin flip model (SFM) studies 36 indicate that VCSELs have the potential to present a pathway to unsupervised learning, via the neuron-inspired spike-timing dependent plasticity (STDP) technique. Also very recently, the authors have outlined the potentials of VCSEL neurons for image processing 37 , 38 and encoding functionalities 39 . However, in these early image processing reports, the VCSEL neurons acted as spike thresholding elements, requiring the image pixel information to be pre-processed offline.…”