Cselt-Centro Studi E Laboratori Telecomunicazioni S.p.a.

Cselt- Centro Studi E Laboratori Telecommunicazioni Spa

Telecom Italia

Agilent Technologies, Inc.

Sip - Societa Italiana Per L-Esercizio Delle Telecomunicazioni P.a.

Telecom Italia Lab S.p.a.

Giorgio Grego

Giuseppe Cocito

Luigi Tallone

Gianni Coppa

Eros Modone

Diego Roccato

Michele Lupano

Pada Regio

Luisella Chiaro

A method for inputting commands to a holographic input system, includes the steps of generating a virtual image of an input device by illuminating a hologram of the input device by means of a corresponding reference beam, the hologram being prerecorded on a holographic support; optically detecting a position of at least one actuator for operating the input device with respect to the virtual image of the input device; and issuing at least one command signal corresponding to the position of that at least one actuator as optically detected. The optical detection operation further includes providing at least one actuation hologram corresponding to the at least one actuator being placed at a specified position with respect to the virtual image of the input device, illuminating the at least one actuator with a beam, in order to obtain scattering into a corresponding object beam interacting with one actuation hologram through the corresponding object beam; generating a respective actuation detection beam through the interaction; and detecting the respective actuation detection beam to issue the command signal.

Inputting information using holographic techniques

A method and an apparatus for reading passive tags affixed to objects to be identified and tracked by a radio frequency identification system are disclosed. An interrogating station sends radio-frequency inquiry signals toward the passive tags through an antenna array and receives the response signals from the tags through the same array. Electronic circuitry for processing such response signals has a phase conjugator submitting each received signal to phase conjugation, and the phase-conjugated signals are back transmitted to the passive tags. Retrodirectivity of the antenna array obtained through the phase conjugation allows a precise object identification and tracking also at relatively long distances.

Method of and apparatus for long distance reading of passive tags in radio frequency identification systems

A controlled area (A) is configured as a telecommunications cellular system location area, connection of cellular system mobile terminals (T) to such location area (A) is checked. A detected connection indicates that the bearer of the terminal (T) accessed the controlled area, which information can thus be used both to prevent unauthorized access and to certify and document authorized access also by interrogation through the system. The fact that terminal (T) has been kept switched on inside the controlled area despite this being interdicted can also be detected and such behavior can be debited to the terminal (T) involved and/or the terminal can be inhibited by means of temporary deactivation of the terminal (T).

Method for detecting access to controlled areas and related system

To manufacture polarization-maintaining optical fibers, a fiber is directly and continuously irradiated with at least one beam of UV radiation during drawing and before application of external coatings.

Method of making polarization-maintaining optical fibers

To determine the polymerization profile of a layer of polymeric material, particular a coating of an optical waveguide, a source sends a light radiation towards the layer under test at different angles of incidence, and both the portion of radiation reflected by the layer and the portion transmitted by the layer are converted into electrical signals. The electrical signals are supplied to devices for measuring their intensity, and a processing system processes the intensity values to obtain a value of the refractive index at a different depth inside the layer and to obtain the degree of polymerization at each depth by comparison with the values of the refractive index of a precursor of the polymer and of the fully polymerized material.

Method of and device for determining the polymerization profile of a

A method and device are provided for measuring the viscoelastic characteristics of polymeric coatings of optical fibers directed on a coated fiber. The ends of the fiber are inserted into a pair of clamps which are shaped in such a way as to hold the coating without tearing it and to allow it to slide longitudinally over the fiber. The clamps impart a relative oscillating motion to the coating creating a longitudinal tensile stress of periodically varying intensity. The clamps and their support are part of a rheometer which measures the opposing stress and processes the stress data to give the desired characteristics.

Method and device for the viscoelastic properties of polymeric coatings

The radiation to be analyzed is sent onto an interference filter which selects different portions of the radiation spectrum in correspondence with different incidence angles. The intensity values of the radiation outgoing from the element are stored by a measuring and data processing unit which processes such values with the transfer function of the element to obtain the information on the spectrum.

High-resolution spectroscopy system

An optical spectroscopy system, wherein a pulse of a radiation to be analyzed is sent to a diffractive element presenting high temporal chromatic dispersion, and information relevant to the radiation spectrum is obtained from pulse broadening in the time domain.

Optical spectroscopy system

The system uses a monochromatic radiation source (1) and an acousto-optic modulator (2), which acts as a Bragg modulator and is driven by a frequency which is caused to periodically vary. The modulator emits a first beam having the same wavelength as the source and a second beam, whose wavelength and emission direction vary with the modulating frequency and which is collimated. For measuring angular displacements, the collimated beam is recombined with the first beam after traversing a plate (5) with parallel and plane faces integral for the rotation with a moving device, and a photodetector (12) generates a beat signal whose frequency depends on the angular position of the plate (5). For measuring linear displacements, the two beams are directly sent onto a detector (12) integral with the moving device.

Interferometric optical system for measuring linear or angular

A device for the correlation between optical beams having spatially modulated intensities has an active glass window, which on one side is illuminated at the same time by a reading and a pumping beam through one or a plurality of semitransparent mirrors. The reading beam has radiations with a wavelength equal to that of a transition between an intermediate and fundamental energy level. The pump beam has radiations with a wavelength corresponding to the energy of the highest power level of the material forming the active glass, obtaining on the other side of the window a light beam representing the correlation betwen the pumping and reading beams.

Device for the correlation between optical beams

An electrooptic deflector composed of a plate made of a material with a refractive index which can be modified by the application of an electrical field, whereinto a collimated optical beam can be injected in direction parallel to the electrodes deposited on a plate face. Said electrodes are parallel to one another, equally-spaced and separately connected to voltage sources apt to increase the refractive index in the material passing from an electrode to the next. The emerging optical beam is deflected in the direction wherein the refractive index increases.

Electrooptic deflector

The distributed temperature sensor employs an optical fiber as sensing element located in an ambient or near a body of which the temperature is to be monitored or measured. A source of light pulses sends into the fiber, pulses of predetermined duration. The backscattered radiation is collected for each pulse and the frequency spectrum variations in the backscattered radiation with respect to the incident radiation are analyzed. A computer obtains the temperature from said variations. The source and the spectrum variation analyzer are part of an optical time domain reflectometer which allows the temperature information to be associated with the information on the position of the backscattering point along the fiber.

Distributed temperature sensor with optical-fiber sensing element

The method of measuring viscosity of a glass body, such as an optical preform related to at least its softening temperature, exploits the scattering effects the body introduces into a substantially monochromatic radiation passing through it; more particularly, the width of the spectral line due to Brillouin scattering is measured. The temperature of the body can also be determined by measuring the width of the line generated by Rayleigh scattering. The method is of particular interest for measurements on glasses.

Method of measuring viscosity of a body

A static interferometric ellipsometer, wherein a source (3) generates a coherent light-beam with two monochromatic radiations at slightly different frequencies. A first photodetector (6) generates a first beat between the two radiations, to be used as reference. A second photodetector (9) generates a second beat between the two radiations, after they have been polarized in perpendicular planes and separated so that one of them is reflected onto the photodetector (9) by the sample under test (1,2). A measuring and computing system (11) determines the optical properties of said sample starting from the intensity of the second beat and from the relative phase between the two beats.

Static interferometric ellipsometer

A method of making optical performs from which optical fibers are drawn after collapsing of the preform, which comprises depositing by a vapor-phase reaction a plurality of layers on the inner surface of a support tube and controlling the temperature profile around the perimeter of the support so that the thickness of the deposit varies between at least one maximum and at least one minimum. Upon collapse of the support this gives rise to a core having a noncircular cross section.

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Venaria, Italy

Giorgio Grego