Near-infrared Hong-Ou-Mandel interference on a silicon quantum photonic circuit

TL;DR

This paper demonstrates near-infrared Hong-Ou-Mandel interference on a silicon photonic chip with high visibility, using bright two-photon states and analyzing factors affecting quantum interference quality for scalable quantum information applications.

Contribution

It reports the first on-chip near-infrared Hong-Ou-Mandel interference with high visibility and analyzes the sources of residual imperfections for scalable quantum photonics.

Findings

On-chip quantum interference visibility of 90.5%

Generation of spectrally-bright 1557-nm two-photon states

Analysis of multipair contributions and visibility compensation techniques

Abstract

Near-infrared Hong-Ou-Mandel quantum interference is observed in silicon nanophotonic directional couplers with raw visibilities on-chip at 90.5%. Spectrally-bright 1557-nm two-photon states are generated in a periodically-poled KTiOPO4 waveguide chip, serving as the entangled photon source and pumped with a self-injection locked laser, for the photon statistical measurements. Efficient four-port coupling in the communications C-band and in the high-index-contrast silicon photonics platform is demonstrated, with matching theoretical predictions of the quantum interference visibility. Constituents for the residual quantum visibility imperfection are examined, supported with theoretical analysis of the sequentially-triggered multipair biphoton contribution and techniques for visibility compensation, towards scalable high-bitrate quantum information processing and communications.