Optical
Systems using optical substrates
Systems using Optical
Boson sampler
sampling from the permanent of a unitary matrix (classically #P-hard)
Identical single photons enter an m-mode linear optical network (beam splitters and phase shifters implementing a unitary U). Detectors at the outputs sample from a distribution whose probabilities ar...
Coherent Ising machine (OPO network)
Ising Hamiltonian ground state / combinatorial optimization (MAX-CUT, QUBO)
A network of degenerate optical parametric oscillator (DOPO) pulses circulating in a fiber ring cavity. Each pulse can oscillate in one of two phase states (0 or π), encoding a spin. Measurement-feedb...
Diffractive deep neural network (D²NN)
neural network inference / image classification (at the speed of light)
A stack of passive, 3D-printed diffraction layers implements a trained neural network entirely in the optical domain. Each layer is a mask with pixel-wise phase or amplitude modulation, trained offlin...
Optical correlator (4f / VanderLugt filter)
cross-correlation / matched filtering (pattern detection in O(1) optical time)
A 4f lens system consists of two lenses separated by twice their focal length with a holographic or spatial-light-modulator (SLM) filter at the shared Fourier plane. The first lens computes the Fourie...
Photonic integrated circuit (silicon photonics)
matrix-vector multiplication / unitary linear transforms (for neural network inference)
Arrays of Mach-Zehnder interferometers (MZIs) and microring resonators on a silicon chip implement programmable unitary matrices in the optical domain. Light encodes values as amplitude or phase; pass...
Reservoir computer
temporal pattern recognition / dynamical system computation
Fixed nonlinear dynamical system (reservoir) coupled to a trained linear readout layer. Input drives the reservoir dynamics, output layer learns to extract desired computations. Echo state networks an...