All-optical nonlinear activation based on sound waves enables synthetic frequency dimensional neural networks/ machine learning accelerators

https://www.eurekalert.org/news-releases/1080406

"simple neural network of weighted sum of bits of incoming information/ nonlinear activation functions ReLU, sigmoid, or tanh functions, transforming inputs' weighted sum into artificial neural network... optical information does not leave optical domain, directly processed in optical fibers or photonic waveguides... stimulated Brillouin scattering causes optical nonlinear change in input information depending on optical intensity... preserves optical data bandwidth, avoids electro-optic conversion, maintains signal coherence"