Mutually unbiased measurements for high-dimensional time-bin–based photonic states

The task of measuring in two mutually unbiased bases is central to many quantum information protocols, as well as being of fundamental interest. Increasingly, there is an experimental focus on generating and controlling high-dimensional photonic states. One approach is to use the arrival time of a photon, which can be split into discrete time bins. An important problem associated with such states is the difficulty in experimentally realizing a measurement that is mutually unbiased with respect to the time of arrival. We propose a simple and compact scheme to measure in both the time-of-arrival basis and a basis that is approximately mutually unbiased with respect to the arrival time