Search results for "Rating"

showing 10 items of 2021 documents

Self-referenced phase reconstruction proposal of Ghz bandwidth non-periodical optical pulses by in-fiber semi-differintegration

2011

Abstract We propose two new techniques able to retrieve the phase profile of a given temporal optical pulse based on the use of in-fiber semi-differintegral operators, where by semi-differintegration we mean either a 0.5th-order differentiation or integration. In both cases, the signal's temporal phase can be obtained by simple dividing two temporal intensity profiles, namely the intensities of the input and output pulses of a spectrally shifted semi-differintegral operator. In both cases, we obtained simple analytical expressions for the phase profile. The techniques are self-referenced and well-suited for real-time applications. We numerically prove the viability of these proposals.

PhysicsMode volumePhase reconstructionMulti-mode optical fiberbusiness.industryFiber optics systemsBandwidth (signal processing)Fractional calculusPolarization-maintaining optical fiberLong-period fiber gratingAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsOpticsOperator (computer programming)Fiber Bragg gratingFiber optic sensorFiber Bragg gratingsElectrical and Electronic EngineeringPhysical and Theoretical Chemistrybusiness
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Quantized separations of phase-locked soliton pairs in fiber lasers

2003

Quantized separations of phase-locked soliton pairs in fiber lasers were presented. The relation between the Kelly sidebands and the quantized separations between solitons was confirmed. Simulation results showed that the solitons can see each other at relatively larger distances than they would in the absence of radiation.

PhysicsMode volumebusiness.industrySingle-mode optical fiberPhysics::OpticsPolarization-maintaining optical fiberAtomic and Molecular Physics and OpticsNonlinear Sciences::Exactly Solvable and Integrable SystemsOpticsFiber Bragg gratingMode-lockingFiber laserDispersion-shifted fiberSolitonbusinessNonlinear Sciences::Pattern Formation and SolitonsOptics Letters
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Optimizing the operating temperature of a transition edge sensor

2006

We discuss the theory for optimizing the operating temperature of a voltage biased superconducting transition edge sensor (TES) in terms of energy resolution and speed, considering only internal detector noise sources. The noise processes included in the modeling are the unavoidable Johnson and phonon noise. The phonon noise is calculated for the case of ballistic transport. If other external and excess internal noise sources are not dominant, an optimal operating temperature can be found to minimize the energy resolution. The detector slows down by approximately a factor of two at the optimal energy resolution point.

PhysicsNuclear and High Energy PhysicsOperating temperatureBallistic conductionDetectorTransition edge sensorPhonon noiseInstrumentationNoise (electronics)Energy (signal processing)Computational physicsVoltageNuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
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Continuously Variable Periodic Test Target

1987

CONTINUOUSLY VARIABLE PERIODIC TEST TARGETP. ANDRES*, J. OJEDA- CASTANEDAt, and J.C. BARREIRO*tINAOE, Apartado Postal 216, 72000 Puebla, Pue., Mexico*Departamento de Optica, Universidad de Valencia, 46100 Burjasot, Spain1. INTRODUCTIONThe modulus of the optical transfer function (MTF) of the eye or any other optical system is usuallyevaluated by imaging either several gratings each with different spatial frequency, or a single test tar-get having patterns with different frequencies (USAF resolution chart). In any of these two usual proce-dures, the measurement of the MTF is made at discrete values of the spatial frequency.Here we describe a method based on the self -imaging phenomenon for p…

PhysicsOptical axisOpticsbusiness.industryOptical transfer functionTalbot effectImage processingSpatial frequencyMonochromatic colorGratingbusinessImage resolutionSPIE Proceedings
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Actively Q-switched and modelocked all-fiber lasers

2010

Here we demonstrate active mode-locking (ML) and doubly-active Q-switching mode-locking (QML) of erbium-doped strictly all-fiber lasers. The active ML mechanism relies in the acoustooptic superlattice modulation (AOSLM) effect induced when longitudinal acoustic waves are launched along a fiber Bragg grating. In both regimes - ML as well as QML - we focus on the laser behavior when the AOSLM is driven by traveling acoustic waves, and next we compare these results with those obtained when the AOSLM is driven by standing acoustic waves. In the ML regime, optical pulses were obtained of 530 mW peak power, 700 ps temporal width, at a repetition rate of 4.1 MHz. On the other hand, in the QML regi…

PhysicsOptical fiberPhysics and Astronomy (miscellaneous)business.industryBragg's lawAcoustic waveLaserQ-switchinglaw.inventionOpticsFiber Bragg gratingMode-lockinglawFiber laserbusinessInstrumentationLaser Physics Letters
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Evaluation of all-optical demultiplexing in millimeter-wave subcarrier-system for wireless communication

2006

In this paper, a scheme for multiplexing millimeter-wave carriers on a single optical carrier and using an all-optical millimeter-wave demultiplexer is presented. The optical demultiplexing of radio-over-fiber signals is based on dual sideband modulation with suppressed optical carrier combined with the filtering properties of dual over-written fiber Bragg gratings. The performance of the system is investigated using a single optical carrier and independent data modulated millimeter-wave signals at 20 and 40 GHz. The signals are transmitted over optical fiber, demultiplexed and wirelessly distributed to a mobile unit. It is found that performance of the demultiplexing using fiber Bragg grat…

PhysicsOptical fiberSidebandbusiness.industryPhysics::OpticsMultiplexingSubcarrierAmplitude-shift keyinglaw.inventionOpticsFiber Bragg gratinglawOptical Carrier transmission ratesbusinessQuadrature amplitude modulation2006 International Topical Meeting on Microwave Photonics
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In-fiber all-optical fractional differentiator

2009

We demonstrate that an asymmetrical pi phase-shifted fiber Bragg grating operated in reflection can provide the required spectral response for implementing an all-optical fractional differentiator. There are different (but equivalent) ways to design it, e.g., by using different gratings lengths and keeping the same index modulation depth at both sides of the pi phase shift, or vice versa. Analytical expressions were found relating the fractional differentiator order with the grating parameters. The device shows a good accuracy calculating the fractional time derivatives of the complex field of an arbitrary input optical waveform. The introduced concept is supported by numerical simulations.

PhysicsOptical fiberbusiness.industryPhysics::OpticsGratingPulse shapingAtomic and Molecular Physics and Opticslaw.inventionAmplitude modulationDifferentiatorsymbols.namesakeOpticsFourier transformFiber Bragg gratinglawsymbolsWaveformbusinessOptics Letters
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Observation of Modulational Instability induced by a dynamical Bragg grating in an optical fiber

2001

We present a detailed experimental study on Bragg Modulational Instability in a highly birefringent fiber. The originality of our scheme is that the index modulation is obtained through cross phase modulation with a beating wave.

PhysicsOptical fiberbusiness.industryWave propagationCross-phase modulationPhysics::OpticsCoupled mode theorylaw.inventionModulational instabilitysymbols.namesakeOpticsFiber Bragg gratingModulationlawsymbolsbusinessRaman scatteringNonlinear Guided Waves and Their Applications
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Second-order optical phase transition in a semilinear photorefractive oscillator with two counterpropagating pump waves

2002

Soft-mode onset of coherent oscillation is revealed in a semilinear cavity with two counterpropagating pump waves. From the dynamics of the oscillation intensity and the dynamics of the grating decay with the feedback applied, critical behavior is detected: Both the characteristic time of oscillation onset and grating decay time go to infinity exactly at the threshold coupling strength. A conclusion is made about the similarity of this type of oscillator to the second-order phase transition.

PhysicsPhase transitionOscillationPhysics::OpticsStatistical and Nonlinear PhysicsPhotorefractive effectGratingAtomic and Molecular Physics and OpticsOptical pumpingQuantum electrodynamicsQuantum mechanicsPhase conjugationDiffraction gratingRefractive indexJournal of the Optical Society of America B
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Near-field optical response of a two-dimensional grating of gold nanoparticles

2001

Laboratoire de Physique, Optique Submicronique, Universite´de Bourgogne, Boite Postale 47870, F-21078 Dijon, France~Received 1 August 2000; published 4 April 2001!This article reports on the near-field optical response of a small square grating of gold nanoparticles tailoredby electron-beam lithography. The investigation of the grating is aimed at a deepened understanding ofelectromagnetic interaction among particles due to scattered light fields. Therefore, a photon scanning tunnel-ing microscope is applied to acquire near-field optical images. Two different incident wavelengths are used tocharacterize the intensity and the spatial localization of the electromagnetic near field both in and out…

PhysicsPhotonMicroscopebusiness.industryNear-field opticsNear and far fieldGratinglaw.inventionWavelengthOpticslawbusinessPlasmonExcitationPhysical Review B
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