Search results for "Compres"
showing 10 items of 1107 documents
Towards CEP stable sub two cycle IR pulse compression with bulk material
2010
We demonstrate both experimentally and numerically that self-steepening during propagation in a hollow-fiber followed by linear propagation through glass in the anomalous dispersion enables pulse compression down to 1.9 cycles at 1.8 micron wavelength.
Asymptotic characteristics of parabolic similariton pulses in optical fiber amplifiers
2004
The fundamental asymptotic nature of parabolic similariton pulses in normal-dispersion fiber amplifiers is experimentally demonstrated. With frequency-resolved optical gating characterization measurements with a fixed input pulse energy, the output parabolic pulse characteristics are shown to be invariant with the input pulse profile and duration and to be completely determined only by the amplifier parameters.
Regenerative 40 Gbit/s wavelength converter based on similariton generation.
2005
International audience; We present an all-optical regeneration technique based on spectral filtering of self-similar parabolic pulses (similaritons). In particular, we demonstrate numerically and experimentally that ghost pulses, which occur in the zero bit slots of telecommunication pulse trains, can be effectively suppressed. These results are obtained with a 40 Gbit/s pulse train.
All-Normal-Dispersion Photonic Crystal Fibers Under Prism of Supercontinuum Generation and Pulse Compression
2015
We discuss properties of all-normal-dispersion photonic crystal fibers in context of supercontinuum generation and compression of ultrashort pulses. The application of pump pulses typical for the state of the art Ti:Sapphire lasers allows obtaining quite flat and broad spectra extending more than one octave in this fiber. The influence of initial pump pulse parameters such as pulse energy, duration, and pump wavelength on the SC generation was investigated. It was shown that compression of pulses with such SC spectra allows obtaining a few cycle pulses up to 8.1 fs, if a simple quadratic compressor is used and single cycle pulses up to 2.5 fs, if full phase compensation is provided.
Predicting ultrafast nonlinear dynamics in optical fiber using neural networks
2021
We show how neural networks can be used to model complex and predict nonlinear propagation dynamics in optical fibres for a widerange of input conditions and fibre systems, including pulse compression, ultra-broadband supercontinuum generation, and multimode fiber systems. Our results open up novel perspectives to model and optimize complex nonlinear dynamics and systems.
Multiple four-wave mixing in optical fibers: 1.5–3.4-THz femtosecond pulse sources and real-time monitoring of a 20-GHz picosecond source
2010
International audience; In this work, we report recent progress on the design of all-fibered ultra-high repetition-rate pulse sources for telecommunication applications around 1550 nm. The sources are based on the non-linear compression of an initial beat-signal through a multiple four-wave mixing process taking place into an optical fiber. We experimentally demonstrate real-time monitoring of a 20 GHz pulse source having an integrated phase noise 0.01 radian by phase locking the initial beat note against a reference RF oscillator. Based on this technique, we also experimentally demonstrate a well-separated high-quality 110 fs pulse source having a repetition rate of 2 THz. Finally, we show…
Nonlinear repolarization dynamics in optical fibers: transient polarization attraction
2011
International audience; In this work, we present a theoretical and experimental study of the response of a lossless polarizer to a signal beam with a time-varying state of polarization (SOP). By lossless polarizer, we mean a nonlinear conservative medium (e.g., an optical fiber) that is counterpumped by an intense and fully polarized pump beam. Such a medium transforms input uniform or random distributions of the SOP of an intense signal beam into output distributions that are tightly localized around a well-defined SOP. We introduce and characterize an important parameter of a lossless polarizer--its response time. Whenever the fluctuations of the SOP of the input signal beam are slower th…
Compression of Polarized 3He
1991
This article gives a status report on the polarized 3He target development work at Mainz. It is based on the optical pumping of the 3S1 state of 3He with subsequent metastability spin exchange to the ground state atoms. This pumping scheme is very efficient at 3He pressures of about 1 Torr; for high density targets, however, a mechanical compression of the polarized gas is needed in a second step. First results with a Toepler compression pump look promising and will be discussed in the following.
He-3 spin filter for neutrons
2005
The strongly spin-dependent absorption of neutrons in nuclear spin-polarized (3)He opens up the possibility of polarizing neutrons from reactors and spallation sources over the full kinematical range of cold, thermal and hot neutrons. This paper gives a report on the neutron spin filter (NSF) development program at Mainz. The polarization technique is based on direct optical pumping of metastable (3)He atoms combined with a polarization preserving mechanical compression of the gas up to a pressure of several bar, necessary to run a NSF. The concept of a remote type of operation using detachable NSF cells is presented which requires long nuclear spin relaxation times of order 100 hours. A sh…
Scope Oriented Thermoeconomic analysis of energy systems. Part II: Formation Structure of Optimality for robust design
2010
This paper represents the Part II of a paper in two parts. In Part I the fundamentals of Scope Oriented Thermoeconomics have been introduced, showing a scarce potential for the cost accounting of existing plants; in this Part II the same concepts are applied to the optimization of a small set of design variables for a vapour compression chiller. The method overcomes the limit of most conventional optimization techniques, which are usually based on hermetic algorithms not enabling the energy analyst to recognize all the margins for improvement. The Scope Oriented Thermoeconomic optimization allows us to disassemble the optimization process, thus recognizing the Formation Structure of Optimal…