Abstract

Flying qubits encoded into single photons are fundamental resource for quantum communication and optical quantum computation. In linear-optics quantum computation [1], a crucial element for entangling two qubits is the quantum interference between two photons at a beam splitter when they bunch together via the Hong-Ou-Mandel (HOM) effect [2]. Although numerous tests were demonstrated with various photon sources over the past few decades, the HOM effect has been verified only in a similar manner, as well-known HOM dip, in a postselected fashion using click-by-click photon detections. The HOM dip only reflects a particle-like aspect of the HOM state $(|0.2〉-|2,0〉)/\sqrt{2}$, becoming manifest as phase-independent photonic bunching, while its quantum coherence and entanglement properties as phase-sensitive behavior have been only partly addressed. Moreover, for future scalable quantum computation, synchronization of statistical photon sources is desired.

© 2015 IEEE