This project relates to the calculation of the Hong-Ou-Mandel effect in 3-channel interferometers using single photons.
The Hong-Ou-Mandel effect is a 'dip' in the probability of both output channels clicking (i.e. having photons travel through them), as the time delay between the photons entering the interferometer approaches zero. If the input photons enter the interferometer simultaneously, then it is highly probable they exit through the same channels. As the time delay between the photons entering increases, the probability of them leaving through different channels at the output approaches 0.5.
The Mathematica Notebook provided extends this calculation to a 3-channel interferometer and a similar valley is plotted.