Certification of genuine time-bin and energy-time entanglement with integrated photonics

TL;DR

This paper introduces an integrated photonic chip capable of certifying genuine time-bin and energy-time entanglement, successfully closing the post-selection loophole and demonstrating Bell inequality violations.

Contribution

The work presents the first integrated photonic device that certifies genuine TB and ET entanglement without post-selection loopholes, using a novel hug interferometric scheme.

Findings

Bell inequality violated by over 10 standard deviations

Device confirms the hug scheme's versatility for TB and ET entanglement

Demonstrates feasibility of compact, integrated quantum entanglement certification

Abstract

Time-bin (TB) and energy-time (ET) entanglement are crucial resources for long-distance quantum information processing. Recently, major efforts have been made to produce compact high-quality sources of TB/ET entangled photons based on solid-state integrated technologies. However, these attempts failed to close the so-called "post-selection loophole". Here, we present an integrated photonic general Bell-test chip for genuine (i.e., free of the post-selection loophole) TB and ET entanglement certification. We report a violation of a Bell inequality by more than 10 standard deviations using our device based on the "hug" interferometric scheme. The experiment also demonstrates that the hug scheme, previously exploited for ET entanglement, can also be used for genuine TB entanglement.