We have demonstrated that a single nonlinear optical waveguide and a spectral pulse shaper can be used to realize frequency-encoded networks with up to 64 inputs and outputs. In our experiment, a bright laser pulse with a shaped complex spectrum is used to realize networks in a so-called quantum pulse gate. The spectrum of the laser pulse defines the structure of the network as well as the output that we look at. By changing the spectrum, we implement networks of different size without having to rebuild the experiment. Our method is set apart from competing approaches to building linear networks by its simplicity, scalability, and high quality of the implemented network.
Our research has been published in Physical Review Research and is available on the arXiv.