Monolithic Semiconductor Chips as a Source for Broadband Wavelength-Multiplexed Polarization Entangled Photons

TL;DR

This paper reports the first direct generation of broadband wavelength-multiplexed polarization entangled photons from a monolithic semiconductor chip, achieving high concurrence without on-chip compensation, advancing integrated quantum photonics.

Contribution

It introduces a novel method for generating ultrabroadband polarization entangled photons directly from a semiconductor chip with record-high concurrence.

Findings

Achieved entangled photons with 95 nm separation in telecom band.

Recorded highest concurrence of 0.98±0.01 among semiconductor sources.

Demonstrated a fully integrated, ultrabroadband entangled photon source.

Abstract

Generating entangled photons from a monolithic chip is a major milestone towards real-life applications of optical quantum information processing including quantum key distribution and quantum computing. Ultrabroadband entangled photons are of particular interest to various applications such as quantum metrology and multi-party entanglement distribution. In this work, we demonstrate the direct generation of broadband wavelength multiplexed polarization entangled photons from a semiconductor chip for the first time. Without the use of any on-chip compensation, interferometry, entangled photons with a signal-idler separation as large as 95 nm in the telecom band were observed. The highest concurrence of 0.98$\pm$0.01 achieved in this work is also the highest, to the best of our knowledge, comparing to all previously demonstrated semiconductor waveguide sources. This work paves the way for fully integrated, ultrabroadband sources of polarization entangled photons.