Open AccessQuantum-correlated photon-pair generation via cascaded nonlinearity in an ultra-compact lithium-niobate nano-waveguide
Author(s) -
Bradley S. Elkus,
Kamal Abdelsalam,
Sasan Fathpour,
Prem Kumar,
Gregory S. Kanter
Publication year - 2020
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.411575
Subject(s) - lithium niobate , second harmonic generation , materials science , optics , physics , laser , optoelectronics
We generate quantum-correlated photon pairs using cascaded χ (2) : χ (2) traveling-wave interactions for second-harmonic generation (SHG) and spontaneous parametric down-conversion (SPDC) in a single periodically-poled thin-film lithium-niobate (TFLN) waveguide. When pulse-pumped at 50 MHz, a 4-mm-long poled region with nearly 300%/Wcm 2 SHG peak efficiency yields a generated photon-pair probability of 7±0.2 × 10 -4 with corresponding coincidence-to-accidental ratio (CAR) of 13.6±0.7. The CAR is found to be limited by Stokes/anti-Stokes Raman-scattering noise generated primarily in the waveguide. A Raman peak of photon counts at 250 cm -1 Stokes shift from the fundamental-pump wavenumber suggests most of the noise that limits the CAR originates within the lithium niobate material of the waveguide.