Customized nonlinearity shaping in imperfect or variable waveguides
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Date
2019-05-31
Authors
Kelly-Massicotte, Jérémy
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Generation of high-quality single photons via heralded parametric downconversion re-
quires careful design of spectral correlations in down-converted photon pairs. One step in
this design process involves customized engineering of ferroelectric domains. In this thesis,
we explore two aspects of such customized domain engineering.
We first explore the impact of fabrication imperfections on two main domain engineering
methods, by simulating domain variations in domain engineered structures. We quantify
the impact by calculating the purity and amplitude of the generated photon. We conclude
that realistic fabrication imperfections do not impair purity and amplitude significantly for
the studied methods. However, high variations of the dispersion relations in the crystal
impact purity and amplitude significantly.
We then introduce two new domain engineering methods designed for mediums with
varying dispersion relations. The first is a generalization of an existing algorithm used to
design the domain configurations. The second method relies on varying the domain sizes.
We show that the first method yields modest improvement, while the second one works
remarkably well, even in conditions with extreme change in dispersion.
Description
Keywords
purity, parametric downconversion, heralded single photons, varying dispersion