Scalable and programmable three-dimensional photonic processor

Three-dimensional photonic chips are superior in handling $N\phantom{\rule{0}{0ex}}P$-complete problems, but their large-scale application is hindered by the difficulty of programming them. The authors experimentally demonstrate a programmable three-dimensional photonic processor capable of solving the maximum clique problem by encoding injection conditions of photons. The prototype shows the potential of photonic computing, and is applied to solve molecular docking problems. The combination of non-von Neumann parallel computing architectures with fully programmable capabilities paves the way for wider practical applications and photonic computational advantages.