73 research outputs found
Spontaneous parametric processes in optical fibers: a comparison
We study the processes of spontaneous four wave mixing and of third-order
spontaneous parametric downconversion in optical fibers, as the basis for the
implementation of photon-pair and photon-triplet sources. We present a
comparative analysis of the two processes including expressions for the
respective quantum states and plots of the joint spectral intensity, a
discussion of phasematching characteristics, and expressions for the conversion
efficiency. We have also included a comparative study based on numerical
results for the conversion efficiency for the two sources, as a function of
several key experimental parameters
Experimental proposal for the generation of entangled photon triplets by third-order spontaneous parametric downconversion in optical fibers
We present an experimental proposal for the generation of photon triplets
based on third-order spontaneous para- metric downconversion in thin optical
fibers. Our analysis includes expressions for the quantum state, which de-
scribes the photon triplets and for the generation rate in terms of all
experimental parameters. We also present, for a specific source design,
numerically calculated generation rates
Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source
We study the third order spontaneous parametric down conversion (TOSPDC)
process, as a means to generate entangled photon triplets. Specifically, we
consider thin optical fibers as the nonlinear medium to be used as the basis
for TOSPDC in configurations where phase matching is attained through the use
of more than one fiber transverse modes. Our analysis in this paper, which
follows from our earlier paper Optics Letters 36, 190 (2011), aims to supply
experimentalists with the details required in order to design a TOSPDC
photon-triplet source. Specifically, our analysis focuses on the photon triplet
state, on the rate of emission, and on the TOSPDC phasematching characteristics
for the cases of frequency degenerate and frequency nondegenerate TOSPDC
Conversion efficiency in the process of co-polarized spontaneous four-wave mixing
We study the process of co-polarized spontaneous four-wave mixing in
single-mode optical fibers, with an emphasis on an analysis of the conversion
efficiency. We consider both the monochromatic-pumps and pulsed-pumps regimes,
as well as both the degenerate-pumps and non-degenerate-pumps configurations.
We present analytical expressions for the conversion efficiency, which are
given in terms of double integrals. In the case of pulsed pumps we take these
expressions to closed analytical form with the help of certain approximations.
We present results of numerical simulations, and compare them to values
obtained from our analytical expressions, for the conversion efficiency as a
function of several key experimental parameters
Theory of cavity-enhanced spontaneous four wave mixing
In this paper we study the generation of photon pairs through the process of
spontaneous four wave mixing (SFWM) in a cavity. Our key interest
is the generation of photon pairs in a guided-wave configuration - fiber or
waveguide - where at least one of the photons in a given pair is matched in
frequency and bandwidth to a particular atomic transition, as required for the
implementation of photon-atom interfaces. We present expressions, along with
plots, for the two-photon joint intensity both in the spectral and temporal
domains. We also present expressions for the absolute brightness, along with
numerical simulations, and show that the presence of the cavity can result in a
flux enhancement relative to an equivalent source without a cavity
Heralded single-photon source utilizing highly nondegenerate, spectrally factorable spontaneous parametric downconversion
We report on the generation of an indistinguishable heralded single-photon
state, using highly nondegenerate spontaneous parametric downconversion (SPDC).
Spectrally factorable photon pairs can be generated by incorporating a
broadband pump pulse and a group-velocity matching (GVM) condition in a
periodically-poled potassium titanyl phosphate (PPKTP) crystal. The heralding
photon is in the near IR, close to the peak detection efficiency of
off-the-shelf Si single-photon detectors; meanwhile, the heralded photon is in
the telecom L-band where fiber losses are at a minimum. We observe spectral
factorability of the SPDC source and consequently high purity (90%) of the
produced heralded single photons by several different techniques. Because this
source can also realize a high heralding efficiency (> 90%), it would be
suitable for time-multiplexing techniques, enabling a pseudo-deterministic
single-photon source, a critical resource for optical quantum information and
communication technology
Quantum state preparation and one qubit logic from third-order nonlinear interactions
We present a study on preparing and manipulating path-like temporal-mode (TM)
qubits based on third-order nonlinear interactions. Specifically, we consider
the process of frequency conversion via difference frequency generation. To
prepare a qubit, we aim to use Gaussian input states to a nonlinear waveguide.
The coupling between the input state and a specific TM is maximized, obtaining
qubits prepared with fidelities close to one. TMs evolve linearly within the
medium; therefore, it is possible to define rotations around any axis contained
in the plane, allowing spanning the full Bloch sphere in two steps.
Particularly, we present a method to obtain any of the Pauli quantum gates by
varying geometric or user-accessible parameters in a given experimental
configuration. Our study allows for experimentally feasible proposals capable
of controllable arbitrary qubit transformations.Comment: 12 pages, 5 figure
Quantum teleportation with hybrid entangled resources prepared from heralded quantum states
In this work we propose the generation of a hybrid entangled resource (HER)
and its further application in a quantum teleportation scheme from an
experimentally feasible point of view. The source for HER preparation is based
on the four wave mixing process in a photonic crystal fiber, from which one
party of its output bipartite state is used to herald a single photon or a
single photon added coherent state. From the heralded state and linear optics
the HER is created. In the proposed teleportation protocol Bob uses the HER to
teleport qubits with different spectral properties. Bob makes a Bell
measurement in the single photon basis and characterizes the scheme with its
average quantum teleportation fidelity. Fidelities close to one are expected
for qubits in a wide spectral range. The work also includes a discussion about
the fidelity dependence on the geometrical properties of the medium through
which the HER is generated. An important remark is that no spectral filtering
is employed in the heralding process, which emphasizes the feasibility of this
scheme without compromising photon flux.Comment: 15 pages, 5 figure
Tailored photon pair preparation relying on full group velocity matching in fibre-based spontaneous four wave mixing
We study photon pair generation through scalar spontaneous four-wave mixing
in single-mode fibre and for frequency-degenerate pumps; we concentrate on
source geometries which fulfil full group velocity matching (GVM), i.e. where
the pump, signal and idler propagate at identical group velocities. We discuss
two experimental techniques which permit the attainment of full GVM, and
discuss the resulting two-photon state properties. In particular, we show that
full GVM can lead to sources which approach phasematching unconstrained by
dispersion and therefore with a remarkably large bandwidth. We also discuss the
generation of nearly-factorablestates as an application of full GVM.Comment: 12 pages, 4 figures. To appear in J. Mod. Opt; PQE-2008 special issu
Third order parametric downconversion: a stimulated approach
We study the process of seeded, or stimulated, third-order parametric
down-conversion, as an extension of our previous work on spontaneous parametric
downconversion (TOSPDC). We present general expressions for the spectra and
throughputs expected for the cases where the seed field or fields overlap
either only one or two of the TOSPDC modes, and also allow for both pump and
seed to be either monochromatic or pulsed. We present a numerical study for a
particular source design, showing that doubly-overlapped seeding can lead to a
considerably greater generated flux as compared with singly-overlapped seeding.
We furthermore show that doubly-overlapped seeding permits stimulated emission
tomography for the reconstruction of the three-photon TOSPDC joint spectral
intensity. We hope that our work will guide future experimental efforts based
on the process of third-order parametric downconversion.Comment: 14 pages, 6 figures. To be published in Physical Review
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