Contextuality in non-interacting measurement

Non-interacting measurement is a phenomenon of seemingly non-local information transfer that arises for a single photon in a cascade of two-arm interferometers. Since contextuality has been identified as a resource for quantum informational tasks, it is reasonable to posit that non-interacting measurement requires contextuality in some form. We confirm this suspicion for the case of imbalanced beam splitters and discuss the exception that admits a noncontextual model. In contrast to existing proofs of contextuality for a single qubit, this scenario involves only pure states and sharp measurements.