Applied Optics,
Journal Year:
2024,
Volume and Issue:
64(2), P. 233 - 233
Published: Dec. 10, 2024
Programmable
photonics
chips
based
on
a
versatile
structure
are
crucial
for
the
next
generation
of
advanced
systems.
In
this
paper,
we
designed
programmable
chip
with
hexagonal
waveguide
mesh
consisting
longitudinally
parallel
arranged
tunable
basic
units
thin-film
lithium
niobate.
We
fabricated
an
effective
area
5.2mm×1.5mm,
which
contains
six
units,
and
tested
its
performance.
The
extinction
ratio
both
output
ports
exceeded
15
dB,
P
π
=46mW
response
time
about
32
µs.
By
programming
through
PC,
it
can
be
configured
as
multi-channel
adjustable
optical
switch,
where
each
port
is
greater
than
dB.
This
applied
to
all-optical
networks
arbitrary
path
switching.
Physical Review Applied,
Journal Year:
2024,
Volume and Issue:
21(1)
Published: Jan. 2, 2024
Implementation
of
quantum
logic
gates
with
linear
optical
elements
plays
a
prominent
role
in
computing
due
to
their
relatively
easy
manipulation
and
realization.
We
present
efficient
schemes
implement
controlled-not
(cnot)
controlled-swap
(Fredkin)
by
using
solely
optics.
encode
the
control
qubits
target
qudits
photonic
polarization
(two-level)
spatial
degrees
freedom
($d$
level),
respectively.
On
basis
hybrid
encoding,
cnot
Fredkin
are
constructed
deterministic
way
without
any
borrowed
ancillary
photons
or
measurement-induced
nonlinearities.
Remarkably,
number
optics
required
gate
has
been
reduced
one
polarizing
beam
splitter,
while
only
$d$
splitters
necessary
generalized
gate.
The
depths
all
1
dimension
independent.
Besides,
fidelity
our
three-qubit
is
higher
than
99.7%
under
realistic
conditions,
which
previous
schemes.
Quantum
light
generated
through
spontaneous
four-wave
mixing
(SFWM)
process
in
nonlinear
materials,
such
as
entangled
photon
pairs
and
single
photons,
is
an
important
resource
for
various
emerging
quantum
applications.
Integrated
photonics
has
enabled
the
generation,
manipulation,
detection
of
states
with
steadily
increasing
scale
complexity
levels.
Importantly,
exploration
on-chip
integration
accumulated
substantial
progresses
recent
years
toward
realization
low-cost,
large-scale
photonic
circuits.
Here,
we
review
underlying
mechanism
discuss
state-of-the-art
SFWM
sources
fabricated
structures
materials
on
chip.
Furthermore,
enumerate
most
appealing
applications
heralding
single-photon
source,
system-level
integration.
Physical review. A/Physical review, A,
Journal Year:
2024,
Volume and Issue:
109(2)
Published: Feb. 20, 2024
Qudit,
a
high-dimensional
quantum
system,
can
provide
larger
Hilbert
space,
and
it
has
been
shown
that
the
space
remarkable
advantages
over
smaller
one
in
information
processing.
However,
is
great
challenge
to
realize
high-fidelity
gates
with
qudits.
Here
we
theoretically
propose
experimentally
demonstrate
four-dimensional
(including
generalized
Pauli
${X}_{4}$
gate,
${Z}_{4}$
all
of
their
integer
powers)
optical
qudits
based
on
polarization-spatial
degree
freedom
single
photon.
Furthermore,
also
polarization-controlled
eight-dimensional
controlled-${X}_{4}$
gate
its
powers.
The
experimental
results
achieve
both
ultrahigh
average
fidelity
$99.73%$
efficiency
$99.47%$,
which
are
above
error
threshold
for
fault-tolerant
computation.
Our
work
paves
way
large-scale
computation
polynomial
resource
cost.
Science Advances,
Journal Year:
2025,
Volume and Issue:
11(5)
Published: Jan. 29, 2025
Contextuality
is
a
hallmark
feature
of
the
quantum
theory
that
captures
its
incompatibility
with
any
noncontextual
hidden-variable
model.
The
Greenberger-Horne-Zeilinger
(GHZ)–type
paradoxes
are
proofs
contextuality
reveal
this
deterministic
logical
arguments.
However,
GHZ-type
paradox
whose
events
can
be
included
in
fewest
contexts
and
brings
strongest
nonclassicality
remains
elusive.
Here,
we
derive
context-cover
number
3
show
saturates
lower
bound
posed
by
theory.
We
demonstrate
time-domain
fiber
optical
platform
recover
prediction
37-dimensional
setup
based
on
high-speed
modulation,
convolution,
homodyne
detection
time-multiplexed
pulsed
coherent
light.
By
proposing
studying
strong
form
high-dimensional
Hilbert
space,
our
results
pave
way
for
exploration
exotic
correlations
systems.
Physical review. A/Physical review, A,
Journal Year:
2024,
Volume and Issue:
109(4)
Published: April 2, 2024
Entangled
photons
(biphotons)
in
the
time-frequency
degree
of
freedom
play
a
crucial
role
both
foundational
physics
and
advanced
quantum
technologies.
Fully
characterizing
them
poses
key
scientific
challenge.
Here,
we
propose
theoretical
approach
to
achieving
complete
tomography
biphotons
by
introducing
frequency
shift
one
arm
combination
interferometer.
Our
method,
generalized
interferometer,
enables
reconstruction
full
complex
joint
spectral
amplitude
associated
with
sum
difference
single
In
contrast,
Hong-Ou-Mandel
N00N
state
interferometers
only
allow
for
partial
biphotons,
either
or
sum.
This
provides
an
alternative
method
characterization
arbitrary
two-photon
exchange
symmetry
holds
potential
applications
high-dimensional
information
processing.
Acta Physica Sinica,
Journal Year:
2024,
Volume and Issue:
73(7), P. 074201 - 074201
Published: Jan. 1, 2024
In
recent
years,
the
high-dimensional
properties
of
orbital
angular
momentum
degree
freedom
light
have
attracted
extensive
attention.
This
has
been
studied
and
used
in
many
scientific
fields,
especially
optical
communication
quantum
information.
order
to
fully
utilize
momentum,
non-destructive
separation
different
states
become
a
fundamental
requirement.
However,
existing
beam-splitting
systems
either
lack
stability
cascade
expansibility,
or
separated
are
seriously
damaged,
thus
failing
participate
further
interaction
processes.
this
work,
we
construct
miniature
Mach-Zehnder
interferometer
based
on
beam
displacer,
design
an
splitter,
thereby
realizing
splitting
mode.
theoretical
energy
loss
is
zero
because
there
exists
only
total
reflection
beam.
The
passes
through
same
element,
spatial
deviation
small,
so
splitter
good
stability.
addition,
state
propagation
direction
as
incident
state,
extensibility
easy
use
cascade.
Our
research
result
great
significance
using
other
related
fields.
Physical review. A/Physical review, A,
Journal Year:
2024,
Volume and Issue:
109(3)
Published: March 29, 2024
Quantum
state
engineering,
namely,
the
generation
and
control
of
arbitrary
quantum
states,
is
drawing
more
attention
due
to
its
wide
applications
in
information
computation.
However,
there
no
general
method
theory,
existing
schemes
also
depend
heavily
on
selected
experimental
platform.
In
this
article,
we
give
two
for
generating
task
$c$-partite
$d$-dimensional
system,
both
which
are
based
a
discrete-time
walk
with
${2}^{c}$-dimensional
time-
position-dependent
coin.
The
first
procedure
$d$-step
where
all
$d$
coins
nonidentity,
while
second
an
$O(d)$-step
only
$O(logd)$
nonidentity.
A
concrete
example
preparing
generalized
Bell
states
given
demonstrate
scheme
proposed.
Furthermore,
can
be
applied
alternative
approach
preparation
problem
one
fundamental
tasks
processing.
We
design
circuits
help
our
engineering
that
match
best
current
result
size
depth
circuit
asymptotically.
