Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Frontiers in Optics

Modal, Spectral, and Polarization Entanglement in Guided- Wave Parametric Down-Conversion

Mohammed F. Saleh, Bahaa E. A. Saleh, Malvin Carl Teich

Published Jan 1, 2009• 5 citations
Publisher

Abstract

We offer a comprehensive theoretical study of the properties and applications of modal, spectral, and polarization entanglement of biphotons generated via spontaneous parametric down-conversion in 1-D planar and 2-D circular waveguides using continuous pumping.
DOI
10.1364/fio.2009.fwj1

Related papers

Direct Generation of Hybrid Modal - Polarization Entanglement in a Lithium Niobate Channel Waveguide

Divya Bharadwaj, Krishnan Thyagarajan

We propose a scheme for direct generation of photon pairs exhibiting hybrid entanglement between spatial mode and polarization degrees of freedom in a lithium niobate channel waveguide through a spontaneous parametric down conversion process.

International conference on fiber optics and photonics•Jan 1, 2016•0 citations

Proposal for Generation of Hybrid Entangled States in Waveguide Using Polarization Convertor

Divya Bharadwaj, Krishnan Thyagarajan

In this paper we describe a scheme for generation of hybrid spatial modal–polarization entangled photon pairs using type-II spontaneous parametric down conversion process and the electro optic effect in a domain engineered KTP channel waveguide.

Frontiers in Optics•Jan 1, 2016•0 citations

Biphoton wave packets in parametric down-conversion: Spectral and temporal structure and degree of entanglement

J. M. Mikhailova, P. A. Volkov, Mikhail Vladimirovich Fedorov

We investigate spectral and temporal features and entanglement of biphoton wave packets formed in spontaneous parametric down-conversion with a pulsed laser pump. The degree of entanglement is characterized by the experimentally measurable parameter $R$ defined as the ratio of the coincidence and single-particle spectral widths. In the frequency representation, this parameter is found as a function of the pump-pulse duration $\ensuremath{\tau}$. The function $R(\ensuremath{\tau})$ is shown to have a minimum and even in the minimum, at rather natural conditions, the degree of entanglement is found to be very high $({R}_{\mathrm{min}}=73)$. The Schmidt number $K$ is found analytically for both short and long pump pulses and interpolated for arbitrary pulse durations. All functional dependences of $R$ and $K$ are found to be identical and numerical coefficients are found to be rather close. Two-time temporal wave function of a biphoton state is investigated in detail, and a rather significant difference between the cases of short and long pump pulses is found to occur. In the case of long pulses, the temporal parameter ${R}_{t}$ (defined as the ratio of durations of the single-particle and coincidence signals) is shown to be very close to the Schmidt number $K$.

Physical Review A•Dec 16, 2008•99 citations

Investigating the entanglement structure of down-converted photon pairs

Filippo M. Miatto, Alison M. Yao, Stephen Mark Barnett +2 more

We investigate the entanglement of photons produced by spontaneous parametric down-conversion. We analyse the down-converted state for any pump beam and for any detection modes in the complete Laguerre-Gauss basis.

International Conference on Quantum Information•Jan 1, 2011•1 citation

Modal, spectral, and polarization entanglement in guided-wave parametric down-conversion

Mohammed F. Saleh, Bahaa E. A. Saleh, Malvin Carl Teich

We examine the modal, spectral, and polarization entanglement properties of photon pairs generated in a nonlinear periodically poled two-mode waveguide (one-dimensional planar or two-dimensional circular) via nondegenerate spontaneous parametric down-conversion. Any of the possible degrees of freedom---mode number, frequency, or polarization---can be used to distinguish the down-converted photons while the others serve as attributes of entanglement. Distinguishing the down-converted photons based on their mode numbers enables us to efficiently generate spectral or polarization entanglement that is either narrowband or broadband. On the other hand, when the generated photons are distinguished by their frequencies in a type-0 process, modal entanglement turns out to be an efficient alternative to polarization entanglement. Moreover, modal entanglement in type-II down-conversion may be used to generate a doubly entangled state in frequency and polarization.

arXiv:0904.2923•Physical Review A•May 21, 2009•46 citations

Planar waveguide structures for production of modally entangled biphotons with spectrum broadening

A. R. Tamazyan, Gagik Yu. Kryuchkyan

We study the generation of biphoton modally entangled states in such waveguide structures that lead to spectrum broadening. The process of spontaneous parametric down conversion (SPDC) has been considered for the biphoton generation. The main subject of our study is the dependence of the biphoton spectra on the structure spatial characteristics. The representation of the core structures as definite assembles of nonlinear layers allows us to find analytical description for biphoton spectrum. We show that chirped biphotons with discrete as well as continuous spectra can be generated depending on the waveguide structure. The conditions for spectrum discretization are obtained analytically. It is shown that the biphoton entangled states can be controlled by varying the parameters of the waveguide structure.

arXiv:1707.02433•Jul 8, 2017•0 citations
We investigate spectral and temporal features and entanglement of biphoton wave packets formed in spontaneous parametric down-conversion with a pulsed laser pump. The degree of entanglement is characterized by the experimentally measurable parameter RRR defined as the ratio of the coincidence and single-particle spectral widths. In the frequency representation, this parameter is found as a function of the pump-pulse duration $\ensuremath{\tau}$. The function $R(\ensuremath{\tau})$ is shown to have a minimum and even in the minimum, at rather natural conditions, the degree of entanglement is found to be very high (Rmin=73)({R}_{\mathrm{min}}=73)(Rmin​=73). The Schmidt number KKK is found analytically for both short and long pump pulses and interpolated for arbitrary pulse durations. All functional dependences of RRR and KKK are found to be identical and numerical coefficients are found to be rather close. Two-time temporal wave function of a biphoton state is investigated in detail, and a rather significant difference between the cases of short and long pump pulses is found to occur. In the case of long pulses, the temporal parameter Rt{R}_{t}Rt​ (defined as the ratio of durations of the single-particle and coincidence signals) is shown to be very close to the Schmidt number KKK.
We examine the modal, spectral, and polarization entanglement properties of photon pairs generated in a nonlinear periodically poled two-mode waveguide (one-dimensional planar or two-dimensional circular) via nondegenerate spontaneous parametric down-conversion. Any of the possible degrees of freedom---mode number, frequency, or polarization---can be used to distinguish the down-converted photons while the others serve as attributes of entanglement. Distinguishing the down-converted photons based on their mode numbers enables us to efficiently generate spectral or polarization entanglement that is either narrowband or broadband. On the other hand, when the generated photons are distinguished by their frequencies in a type-0 process, modal entanglement turns out to be an efficient alternative to polarization entanglement. Moreover, modal entanglement in type-II down-conversion may be used to generate a doubly entangled state in frequency and polarization.
We study the generation of biphoton modally entangled states in such waveguide structures that lead to spectrum broadening. The process of spontaneous parametric down conversion (SPDC) has been considered for the biphoton generation. The main subject of our study is the dependence of the biphoton spectra on the structure spatial characteristics. The representation of the core structures as definite assembles of nonlinear layers allows us to find analytical description for biphoton spectrum. We show that chirped biphotons with discrete as well as continuous spectra can be generated depending on the waveguide structure. The conditions for spectrum discretization are obtained analytically. It is shown that the biphoton entangled states can be controlled by varying the parameters of the waveguide structure.