All-Photonic Artificial Neural Network Processor Via Non-linear Optics

An all-photonic computational accelerator encodes information in the amplitudes of frequency modes stored in a ring resonator. Nonlinear optical processes enable interaction among these modes. Both the matrix multiplication and element-wise activation functions on these modes (the artificial neurons) occur through coherent processes, enabling the representation of negative and complex numbers without digital electronics. This accelerator has a lower hardware footprint than electronic and optical accelerators, as the matrix multiplication happens in a single multimode resonator on chip. Our architecture provides a unitary, reversible mode of computation, enabling on-chip analog Hamiltonianecho backpropagation for gradient descent and other selflearning tasks. Moreover, the computational speed increases with the power of the pumps to arbitrarily high rates, as long as the circuitry can sustain the higher optical power.