Synchronization of optical photons for quantum information processing

TL;DR

This paper demonstrates the synchronization of two heralded, pure optical photons using quantum memories, enabling high-visibility Hong-Ou-Mandel interference essential for quantum information processing.

Contribution

It introduces the first demonstration of synchronized pure optical photons via independent quantum memories for quantum interference.

Findings

Achieved controlled storage times up to 1.8 microseconds.

Observed high-purity HOM interference with negative Wigner function.

Processed about 90 events per second with preserved photon purity.

Abstract

A fundamental element of quantum information processing with photonic qubits is the nonclassical quantum interference between two photons when they bunch together via the Hong-Ou-Mandel (HOM) effect. Ultimately, many such pure photons must be processed in complex interferometric networks, and for this it is essential to synchronize the arrival times of the flying photons preserving their purity. Here we demonstrate for the first time the HOM interference of two heralded, pure optical photons synchronized through two independent quantum memories. Controlled storage times up to 1.8 microseconds for about 90 events per second were achieved with purities sufficiently high for a negative Wigner function confirmed with homodyne measurements.