Keywords: Multimode interference, MMI, Coupler, Internal Visualizer, Visualization, Photonic Integrated Circuits, PICs
Similar demonstrations are available in VPIComponentMaker Photonic Circuits and on the VPIphotonics Forum.
 M. Bachmann, P. A. Besse, and H. Melchior, "Overlapping-image multimode interference couplers with a reduced number of self-images for uniform and nonuniform power splitting", Appl. Opt., vol. 34, pp. 6898-6910, 1995.