Correlated photon-pair generation in a periodically poled MgO doped stoichiometric lithium tantalate reverse proton exchanged waveguide

TL;DR

This paper reports on the generation of correlated photon pairs using a periodically poled MgO-doped lithium tantalate waveguide through a cascaded nonlinear process involving second harmonic generation and downconversion.

Contribution

It demonstrates a novel integrated waveguide platform for photon-pair generation via cascaded second-order nonlinear processes in lithium tantalate.

Findings

Photon pairs generated at 42 per second.

Coincidence to accidental ratio of 0.7.

Successful demonstration of cascaded nonlinear process in the waveguide.

Abstract

We demonstrate photon-pair generation in a reverse proton exchanged waveguide fabricated on a periodically poled magnesium doped stoichiometric lithium tantalate substrate. Detected pairs are generated via a cascaded second order nonlinear process where a pump laser at wavelength of 1.55 $\mu$m is first doubled in frequency by second harmonic generation and subsequently downconverted around the same spectral region. Pairs are detected at a rate of 42 per second with a coincidence to accidental ratio of 0.7. This cascaded pair generation process is similar to four-wave-mixing where two pump photons annihilate and create a correlated photon pair.