Four-Photon Quantum Interferometry at a Telecom Wavelength

TL;DR

This paper demonstrates four-photon quantum interference at telecom wavelengths, advancing quantum information processing by developing a suitable photon source and observing interference effects with potential practical applications.

Contribution

The study introduces an efficient telecom-wavelength photon source and experimentally demonstrates four-photon interference with reduced fringe intervals, enabling progress in quantum computing.

Findings

Successful demonstration of four-photon quantum interference at telecom wavelengths

Observation of reduced fringe intervals corresponding to four-photon NOON states

Development of a high-quality photon source for quantum experiments

Abstract

We report the experimental demonstration of four-photon quantum interference using telecom-wavelength photons. Realization of multi-photon quantum interference is essential to linear optics quantum information processing and measurement-based quantum computing. We have developed a source that efficiently emits photon pairs in a pure spectrotemporal mode at a telecom wavelength region, and have demonstrated the quantum interference exhibiting the reduced fringe intervals that correspond to the reduced de Broglie wavelength of up to the four photon `NOON' state. Our result should open a path to practical quantum information processing using telecom-wavelength photons.