An All-Optical Artificial Neural Network

Since the dawn of digital computing, scientists have dreamed of building artificial neural network that would function like biological brain and solve difficult problems. As nanophotonic circuits became a reality, researchers have tried to create neural networks that would run at the speed of light, but translating a key mathematical component of artificial neurons, the nonlinear activation function, from the electronic to the optical realm proved elusive.

Now, a nine-member team from the Hong Kong University of Science and Technology, Hong Kong, has built an all-optical artificial neural network and applied it to a complex simulation (Optica, doi:10.1364/OPTICA.6.001132). The network incorporates both linear functions, powered by spatial light modulators, and nonlinear activation functions based on the quantum interference effect known as electromagnetically induced transparency (EIT).

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