Broadband indistinguishability from bright parametric downconversion in a semiconductor waveguide

TL;DR

This paper demonstrates that semiconductor Bragg-reflection waveguides can generate bright, broadband, indistinguishable photon pairs with high efficiency, suitable for advanced quantum photonics applications.

Contribution

It provides the first detailed analysis of broadband indistinguishable photon pair generation in semiconductor BRWs, highlighting their potential for quantum technologies.

Findings

BRWs produce spectrally broadband, indistinguishable photon pairs

The source is bright and efficient, suitable for quantum photonics

Multi-photon contributions affect photon bunching behavior

Abstract

Parametric downconversion (PDC) in semiconductor Bragg-reflection waveguides (BRW) is routinely exploited for photon-pair generation in the telecommunication range. Contrary to many conventional PDC sources, BRWs offer possibilities to create spectrally broadband but nevertheless indistinguishable photon pairs in orthogonal polarizations that simultaneously incorporate high frequency entanglement. We explore the characteristics of co-propagating twin beams created in a type-II ridge BRW. Our PDC source is bright and efficient, which serves as a benchmark of its performance and justifies its exploitation for further use in quantum photonics. We then examine the coalescence of the twin beams and investigate the effect of their inevitable multi-photon contributions on the observed photon bunching. Our results show that BRWs have a great potential for producing broadband indistinguishable photon pairs as well as multi-photon states.