Integrated Quantum Photonics with Annealed and Reverse Proton Exchanged Lithium Niobate

82 Pages·2017·18.01 MB·English

Integrated Quantum Photonics
with Annealed and Reverse
Proton Exchanged Lithium
Niobate waveguides
By
Francesco Lenzini
Bachelor in Physics and Master in Physics
Submitted in fulfilment of
the requirements of the degree of
Doctor of Philosophy
Principal Supervisor:
Dr. Mirko Lobino
Prof. Robert Sang
School of Natural Sciences,
Griffith University,
Australia.
November 24, 2016
c Copyright 2016
(cid:13)
by
Francesco Lenzini
i
This work has not previously been submitted for a degree or
diploma in any university. To the best of my knowledge and
belief, the thesis contains no material previously published or
written by another person except where due reference is made
in the thesis itself.
Francesco Lenzini
ii
Acknowledgment of Papers included in this thesis
IncludedinthisthesisarepapersinChapters2, 3, 4, 5, and6, whichareco-authored
with other researchers. My contribution to each co-authored paper is outlined at the
front of the relevant chapter. The bibliographic details for these papers, including
all authors, are:
Chapter 2: F. Lenzini, S. Kasture, B. Haylock, and M. Lobino, “Anisotropic
•
modelforthefabricationofannealedandreverseprotonexchangedwaveguides
in congruent lithium niobate”, Optics Express 23, 1748-1756 (2015).
Chapter 3: F. Lenzini, A. N. Poddubny, J. Titchener, P. Fisher, A. Boes, S.
•
Kasture, B. Haylock, M. Villa, A. Mitchell, A. S. Solntsev, A. A. Sukhorukov,
and M. Lobino, “Characterization of an integrated multimode photon source
by classical sum-frequency generation”, unpublished.
Chapter 4: S. Kasture, F. Lenzini, B. Haylock, A. Boes, A. Mitchell, E.
•
Streed, and M. Lobino. “Frequency conversion between UV and telecom wave-
lengths in a lithium niobate waveguide for quantum communication with Yb+
trapped ions”, Journal of Optics, 18(10), 16 (2016).
Chapter 5: F. Lenzini, B. Haylock, J. C. Loredo, R. A. Abrahao, N. A.
•
Zakaria, S. Kasture, I. Sagnes, A. Lemaitre, H.-P. Phan, D. V. Dao, P. Senel-
lart, M. P. Almeida, A. G. White, and M. Lobino, “Active demultiplexing of
single-photons from a solid state source”, unpublished.
Chapter 6: B. Haylock, F. Lenzini, S. Kasture, P. Fisher, E. Streed, and
•
M. Lobino, “Nine-channel mid power bipolar pulse generator based on a field
programmablegatearray”,ReviewofScientificInstruments87,054709(2016).
Appropriate acknowledgements of those who contributed to the research but did not
qualify as authors are included in each paper.
iii
Included papers which have been published (Chapter 2, Chapter 4, and Chapter 6)
are versions uploaded on the preprint database arXiv.org . Copyright permissions
for these papers weren’t asked to the corresponding publishing journals.
Francesco Lenzini, November 24 2016
Supervisor:
Mirko Lobino, November 24 2016
iv
Acknowledgments
A PhD starts as a joyful and inspiring adventure where you wish to expand the
boundaries of human knowledge, but it soon reveals itself as an huge pain in the
ass. I would like therefore to acknowledge whoever gave me support during these
three years and several months for bringing my degree to completion. First of all
my supervisor Mirko Lobino, which I consider almost as an uncle, and all the people
I have been working with in the lab, Sachin Kasture, Ben Haylock, Paul Fisher,
Matteo Villa, and Glenn Walker for his patient support in the cleanroom. Thanks
also to all the people that I have met here in Brisbane, and especially to Loukeman,
Ila, Carmen, Luca, and Katt. Finally I would like to thank my lovable parents and
all the australian taxpayers for their very kind economical support (although I gave
them most of my money back buying 50 $ tobacco packs more than twice a week).
v
Abstract
This thesis describes the establishment of a new fabrication facility for the real-
ization of annealed and reverse proton exchanged waveguides in congruent lithium
niobate at Griffith University–Centre for Quantum Dynamics, and their application
in different contexts of integrated quantum photonics technologies.
We demonstrated the development of an accurate numerical model for the design
of waveguides in X-cut and Z-cut substrates and high quality fabrication of both
quasi-phase matched quadratic nonlinear waveguides and fast electro-optic waveg-
uide modulators.
Within the context of nonlinear optical processes, we demonstrated a newly pro-
posed method which efficiently reconstruct the biphoton state produced through
spontaneous parametric down-conversion by the use of only classical measurements.
The validity of the method is tested by a direct comparison with photon-coincidence
counting measurements in a multi-channel integrated nonlinear device fabricated in
our facility.
We also implemented the first frequency conversion of 369.5 nm light –resonant with
the transition of Yb+ trapped ions– to the 1550 nm telecom wavelength range with
a periodically poled waveguide fabricated by the reverse proton exchange technique.
Within the context of electro-optical processes, we showed the first active demulti-
plexingofsingle-photonsemittedfromaquantumdotsourcewithasingleintegrated
device made of a network of electro-optically tunable directional couplers.
The results of this work constitute a relevant contribution in several fields of quan-
tum information science, including development of efficient techniques for the char-
acterization of quantum states, quantum communication with trapped ions, and the
realization of multi-photon sources for intermediate quantum computing protocols.
vi
Contents
Acknowledgment of Papers included in this thesis iii
Acknowledgments v
Abstract vi
Contents vi
List of Figures ix
1 Introduction 2
1.1 Properties of Lithium Niobate . . . . . . . . . . . . . . . . . . . . . . 4
1.1.1 Parametric optical nonlinear processes in Lithium Niobate
crystals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Lithium Niobate waveguides . . . . . . . . . . . . . . . . . . . . . . . 10
1.2.1 Integrated Quantum Photonics with Lithium Niobate waveg-
uides: literature review . . . . . . . . . . . . . . . . . . . . . . 11
1.3 Fabrication methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.3.1 Proton Exchange . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.3.2 Fabrication of quasi-phase matched nonlinear waveguides . . . 17
1.3.3 Fabrication of electro-optic circuits . . . . . . . . . . . . . . . 18
1.4 Structure of the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2 Anisotropic model for the fabrication of Annealed and Reversed
Proton Exchanged waveguides in congruent Lithium Niobate 22
3 Characterization of an integrated multimode photon source by clas-
sical sum-frequency generation 33
vii
4 Frequency conversion between UV and telecom wavelengths in a
lithium niobate waveguide for quantum communication with Yb+
trapped ions 42
5 Active demultiplexing of single-photons from a solid-state source 50
6 Nine Channel Mid-Power Bipolar Pulse Generator Based on a Field
Programmable Gate Array 56
7 Conclusion 62
References 65
viii
List of Figures
1.1 Crystalline structure of lithium niobate in the ferroelectric phase.
The permanent displacement of lithium and niobium ions causes a
spontaneous electric polarization along the Z direction. The figure is
inspired from Ref. [1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 SPDC: a pump photon with frequency ω is annihilated and gener-
p
ates two photons with frequencies ω ,ω spontaneously created from
s i
the vacuum state. DFG: similarly to SPDC, DFG is a parametric
down-conversion process where a a pump photon with frequency ω
p
is annihilated and generates two photons with frequencies ω ,ω .
s DFG
Unlike SPDC, the photon with frequency ω is created by stimulated
s
emission. SFG: two photons with frequencies ω ,ω are annihilated
s i
and generate a photon with frequency ω . Second-harmonic gener-
SFG
ation (SHG) is a particular case of SFG where the two input photons
have a same energy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3 (a): Inverted domains in a periodically poled lithium niobate crystal.
(b): Schematic of a typical experimental setup for standard electric
field poling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.4 Schematic of the three diffusion processes used for the fabrication of
APE and RPE LN waveguides. . . . . . . . . . . . . . . . . . . . . . 15
1.5 (a): Schematic of the PE reactor. A metal beaker containing benzoic
acid isheated upwith anoil-based heatingmantle. Theoil is pumped
in the canals surrounding the beaker with a temperature controlled
oil bath circulator. The stirring bar is controlled by a magnetic stir-
rer placed under the reactor (b): Photograph of the oven used for
annealing and RPE processes. Annealing is performed by placing the
wafer on a metal holder (shown in the figure) on top of the aluminium
block. RPE is performed in a stainless steel cylindrical beaker (not
shown in the figure) placed on top of the aluminium block. . . . . . . 16
ix