All of the information in the world is natively analog. Optical computing, a branch of analog computing, uses photons rather than traditional electronic signals to perform computing operations. Propagation of photons through optical elements performs computation intrinsically by offering fundamental operations like Fourier transform, matrix multiplication, and convolution. Thus, optical computing has a rich history closely following the evolution of neural networks and AI. In this talk, I will present the field of photonic neural networks and our efforts to provide scalable, energy-efficient nonlinear optical computing frameworks for machine learning studies.