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Wolfgang Dultz

Bio: Wolfgang Dultz is an academic researcher from Goethe University Frankfurt. The author has contributed to research in topics: Interferometry & Photon. The author has an hindex of 15, co-authored 141 publications receiving 677 citations. Previous affiliations of Wolfgang Dultz include Deutsche Bundespost & Deutsche Telekom.


Papers
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Journal ArticleDOI
TL;DR: In this article, the rotation of the polarization plane of a light wave traveling in an optical fiber that lies on a space curve based on parallel transport is described and an estimation of the effect due to winding the fiber is presented.
Abstract: The rotation of the polarization plane of a light wave traveling in an optical fiber that lies on a space curve based on parallel transport is described. An estimation of the effect due to winding the fiber is presented.

54 citations

Journal ArticleDOI
TL;DR: This work presents a remarkable optical ``nonlinearity'' of certain polarizing interferometers, which is discovered by using the concept of the topological phase on the Poincar\'e sphere and is demonstrated with a simple experiment.
Abstract: Since Berry introduced topological phases to describe the adiabatic transport of the spin of particles in parameter space, they have become a practical and descriptive concept for understanding interference phenomena in many quantum mechanical systems. For the photon two different applications of this concept were found in crystal optics: (1) the optical activity of helically wound optical fibers and (2) the development of the state of polarization on the Poincar\'e sphere. We present a remarkable optical ``nonlinearity'' of certain polarizing interferometers, which we discovered by using the concept of the topological phase on the Poincar\'e sphere and we demonstrate it with a simple experiment.

48 citations

Patent
29 Apr 1998
TL;DR: In this paper, an integrated optical circuit comprising a silicon substrate and waveguides arranged thereon is described, where at least one photonic crystal is provided as a waveguide, which is formed by a mesh of needles.
Abstract: The invention relates to an integrated optical circuit comprising a silicon substrate (1) and waveguides (2, 3) arranged thereon. At least one photonic crystal is provided as a waveguide, which is formed by a mesh of needles (6). The needles (6) can be produced by corpuscular radiation deposition.

43 citations

Patent
30 Mar 2000
TL;DR: In this paper, a method and a device for reducing the speckle that is formed on a projection display when a coherent light source is used is described. But this method is not suitable for the use of a multi-modal light source.
Abstract: The invention relates to a method and a device for reducing the speckle that is formed on a projection display when a coherent light source (1) is used. Before being projected, the light coming from the light source strikes an electrically controllable optical element (4) with a spatially inhomogeneous index of refraction and penetrates said optical element, whereby the index of refraction within the period of projection is temporally altered. This leads to the averaging out of the speckle pattern on the projection screen (6). A multimode light source is preferably used for illumination and/or the light coming from the light source is split into several spatial modes in order to increase the effect. The light from the light source is preferably split by being coupled into a multimode light-conducting fibre. Said optical element is advantageously a liquid crystal element consisting of at least two liquid crystal layers, to which a position-dependent voltage is applied in order to produce a position-dependent index of refraction and whose birefringence is compensated by the appropriate alignment of the layers in relation to each other.

40 citations

Patent
17 May 1999
TL;DR: In this paper, a method for producing a choice of either single photons or pairs of photons in an optical channel was proposed, comprising the following steps: establishing a two-photon state (photon pair), physically separating said photon pair and obtaining the quantum mechanical correlation in the event that the photons are emitted collinearly.
Abstract: The invention relates to a method for producing a choice of either single photons or pairs of photons in an optical channel (16, 17), comprising the following steps: establishing a two-photon state (photon pair); physically separating said photon pair and obtaining the quantum mechanical correlation in the event that the photons are emitted collinearly; coupling each photon into one optical channel (14, 14', 14') respectively, one channel (15, 15', 15') containing an interferometer (7-13) with a variable difference in optical paths δ1F-δ1S and the other channel containing an optical retardation route (19) of optical length δ1; physically bringing the two channels together with a beam splitter (18, 31-36); matching the values δ1F, δ1S and δ1 in such a way that the probability K of coincidences between the outputs (16, 17) of the beam splitter can be either approximately K=0 or approximately K=1 or approximately a predetermined intermediate value, K=0 corresponding to a photon pair in one of the output channels (16, 17) of the beam splitter and K=1 corresponding to two single photons in the two output channels of the beam splitter. The invention provides a means of producing an optical separating filter or gate for either single photons or photon pairs which can be used in quantum cryptography and as a basic element of a quantum optical calculating machine.

36 citations


Cited by
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Journal ArticleDOI
TL;DR: The history, fabrication, theory, numerical modeling, optical properties, guidance mechanisms, and applications of photonic-crystal fibers are reviewed.
Abstract: The history, fabrication, theory, numerical modeling, optical properties, guidance mechanisms, and applications of photonic-crystal fibers are reviewed

1,488 citations

Journal ArticleDOI
TL;DR: In this article, the authors review the development of the q-plate idea and some of the most significant results that have originated from it, and briefly touch on many other related findings concerning the interaction of the spin and orbital angular momentum of light.
Abstract: A few years ago the possibility of coupling and inter-converting the spin and orbital angular momentum (SAM and OAM) of paraxial light beams in inhomogeneous anisotropic media was demonstrated. An important case is provided by waveplates having a singular transverse pattern of the birefringent optical axis, with a topological singularity of charge q at the plate center, hence named 'q-plates'. The introduction of q-plates has given rise in recent years to a number of new results and to significant progress in the field of orbital angular momentum of light. Particularly promising are the quantum photonic applications, because the polarization control of OAM allows the transfer of quantum information from the SAM qubit space to an OAM subspace of a photon and vice versa. In this paper, we review the development of the q-plate idea and some of the most significant results that have originated from it, and we will briefly touch on many other related findings concerning the interaction of the SAM and OAM of light.

480 citations

Journal ArticleDOI
TL;DR: This source of quantum-correlated photon pairs based on parametric fluorescence in a fiber Sagnac loop, given its spectral properties and robustness, is well suited for use in fiber-optic quantum communication and cryptography networks.
Abstract: In this letter, we present a source of quantum-correlated photon pairs based on parametric fluorescence in a fiber Sagnac loop. The photon pairs are generated in the 1550-nm fiber-optic communication band and detected with InGaAs-InP avalanche photodiodes operating in a gated Geiger mode. A generation rate > 10/sup 3/ pairs/s is observed, which is limited by the detection electronics at present. We also demonstrate the nonclassical nature of the photon correlations in the pairs. This source, given its spectral properties and robustness, is well suited for use in fiber-optic quantum communication and cryptography networks.

326 citations

Journal ArticleDOI
Franco Gori1
TL;DR: It is shown that, for a generic polarization state of the incident field, such a grating gives rise to first-order diffracted beams with counterrotating circular polarizations and can be used for measuring the Stokes parameters of a light beam in an achromatic manner.
Abstract: Ordinary gratings act on the amplitude and (or) the phase of a wave front. Polarization gratings produce instead a periodic modulation of the state of polarization. A simple grating of the latter type is constituted by a linear polarizer whose orientation varies periodically along a line. It is shown that, for a generic polarization state of the incident field, such a grating gives rise to first-order diffracted beams with counterrotating circular polarizations. It is also shown that such a grating can be used for measuring the Stokes parameters of a light beam in an achromatic manner. Several extensions are briefly discussed.

294 citations

Patent
08 Jun 1998
TL;DR: In this article, the authors proposed a highly efficient channel drop filter employing a coupling element including a resonator-system between two waveguides, which contains at least two resonant modes.
Abstract: A highly efficient channel drop filter. The filter employs a coupling element including a resonator-system between two waveguides, which contains at least two resonant modes. The resonator-system includes one or more interacting resonant cavities which in addition to being coupled to the waveguides, can also be coupled directly among themselves and indirectly among themselves via the waveguides. Each component of the coupling element can be configured or adjusted individually. The geometry and/or dielectric constant/refractive index of the resonator-system are configured so that the frequencies and decay rates of the resonant modes are made to be substantially the same. The filter can achieve 100% signal transfer between the waveguides at certain frequencies, while completely prohibiting signal transfer at other frequencies. In exemplary embodiments, the filter is configured with photonic crystals. In accordance with alternative embodiments of the invention, the filter is configured as an absorption induced on/off switch and modulator. The switching action is achieved with either electrical or optical absorption.

289 citations