Maximizing Post-selected Quantum Correlations from Classical Interference in a Multi-core Fiber Beamsplitter

TL;DR

This paper demonstrates how classical light in multi-core fiber beam splitters can generate and maximize quantum correlations like discord through fourth-order interference, with potential applications in quantum communication.

Contribution

It introduces a novel multi-core fiber beam splitter setup that maximizes quantum discord from classical inputs, advancing quantum correlation control in photonic networks.

Findings

High-quality fourth-order interference observed between different cores

Quantum discord can be maximized by adjusting input intensity ratios

Self-interference of two-photon wavepackets demonstrated

Abstract

Fourth-order interference is an information processing primitive for photonic quantum technologies. When used in conjunction with post-selection, it forms the basis of photonic controlled logic gates, entangling measurements, and can be used to produce quantum correlations. Here, using classical weak coherent states as inputs, we study fourth-order interference in novel $4 \times 4$ multi-port beam splitters built within multi-core optical fibers. Using two mutually incoherent weak laser pulses as inputs, we observe high-quality fourth order interference between photons from different cores, as well as self-interference of a two-photon wavepacket. In addition, we show that quantum correlations, in the form of quantum discord, can be maximized by controlling the intensity ratio between the two input weak coherent states. This should allow for the exploitation of quantum correlations in future telecommunication networks.