Search results for "Modula"
showing 10 items of 1481 documents
Periodic time-domain modulation for the electrically tunable control of optical pulse train envelope and repetition rate multiplication
2012
An electrically tunable system for the control of optical pulse sequences is proposed and demonstrated. It is based on the use of an electrooptic modulator for periodic phase modulation followed by a dispersive device to obtain the temporal Talbot effect. The proposed configuration allows for repetition rate multiplication with different multiplication factors and with the simultaneous control of the pulse train envelope by simply changing the electrical signal driving the modulator. Simulated and experimental results for an input optical pulse train of 10 GHz are shown for different multiplication factors and envelope shapes. © 2006 IEEE.
Asymptotic properties of incoherent waves propagating in an all-optical regenerators line
2007
International audience; We present an original method to generate optical pulse trains with random time-interval values from incoherent broadband sources. More precisely, our technique relies on the remarkable properties of a line made of cascaded self-phase modulation-based optical regenerators. Depending on the regenerator parameters, various regimes with noticeably different physical behaviors can be reported.
An Effective Satellite Remote Sensing Tool Combining Hardware and Software Solutions
2019
In this paper we propose a new effective remote sensing tool combining hardware and software solutions as an extension of our previous work. In greater detail the tool consists of a low cost receiver subsystem for public weather satellites and a signal and image processing module for several tasks such as signal and image enhancement, image reconstruction and cloud detection. Our solution allows to manage data from satellites effectively with low cost components and portable software solutions. We aim at sampling and processing of the modulated signal entirely in software enabled by Software Defined Radios (SDR) and CPU computational speed overcoming hardware limitation such as high receive…
A Hybrid Frequency-Space Approach for Shape Measurement by Shadow Moiré Technique with Carrier Fringe Pattern
2006
In this paper, a novel methodology to process fringe pattern is presented. The core of the signal processing technique is the use of the direction information, a modulo 2pi quantity that locally informs about the direction along which fringes grow with maximum rate. By using this information, it was possible to perform adaptive, direction- and orientation-based operations on fringe images in order to remove unwanted effects, to enhance the contrast and to extract the phase information encoded. The method has been applied on shadow moire interferograms with carrier fringes in order to measure the surface of small objects. The developed algorithm allows to process fringes whose phase informat…
Towards an analytical framework for tailoring supercontinuum generation.
2016
A fully analytical toolbox for supercontinuum generation relying on scenarios without pulse splitting is presented. Furthermore, starting from the new insights provided by this formalism about the physical nature of direct and cascaded dispersive wave emission, a unified description of this radiation in both normal and anomalous dispersion regimes is derived. Previously unidentified physics of broadband spectra reported in earlier works is successfully explained on this basis. Finally, a foundry-compatible few-millimeters-long silicon waveguide allowing octave-spanning supercontinuum generation pumped at telecom wavelengths in the normal dispersion regime is designed, hence showcasing the p…
Optical retarder system with programmable spectral retardance.
2014
An optical system that works as a retarder waveplate with programmable spectral retardance is proposed. The system is based on a pixelated liquid crystal on silicon (LCoS) spatial light modulator (SLM). The input light beam is spectrally dispersed and different spectral components are projected onto different pixels of the LCoS-SLM. A different retardance is then addressed for each pixel, adapted to the incoming wavelength. Light reflected from the SLM is then recombined by the same setup. In this way a programmable polarization spectrum can be encoded. We illustrate the broadband characterization that is required for proper use of the system. Then several examples are shown, including spec…
A PV plant simulator for testing MPPT techniques
2013
This paper introduces a versatile and reliable photovoltaic systems simulator. It includes the main components of a photovoltaic plant: a PV string and a PWM controlled boost chooper. The key feature of this simulator is the ability to consider different and non-uniform irradiation and temperature conditions (partial shading and partial heating of the strings). All the different I-V and P-V or P-I characteristics can then be determined in such non-uniform irradiation and temperature conditions, with the aim to try different MPPT algorithms. The simulator also allows to verify an enhanced version of the Incremental Conductance algorithm (IncCond) where, in order to reach the real absolute ma…
Adjuvant volumetric-modulated arc therapy with simultaneous integrated boost in endometrial cancer. Planning and toxicity comparison
2014
Objective. To report dosimetric and acute toxicity data in prospectively enrolled high-intermediate risk endometrial cancer (HIR-EC) patients postoperatively irradiated by simultaneous integrated boost volumetric modulated arc therapy (SIB-VMAT). Methods. Thirty prospectively enrolled HIR-EC patients were postoperatively treated by SIB-VMAT. Target coverage, dose homogeneity, and sparing of organs at risk (OARs) were compared with corresponding data retrieved from an historical control (30 consecutive selected matched patients) treated by concomitant boost three-dimensional conformal radiotherapy (3D CRT CB) from a previously published study (ADA-I trial). All patients received 45 Gy on pel…
Weekly Cisplatin and Volumetric-Modulated Arc Therapy With Simultaneous Integrated Boost for Radical Treatment of Advanced Cervical Cancer in Elderly…
2016
Background: To evaluate the feasibility and clinical preliminary results of weekly cisplatin and volumetric-modulated arc therapy to the pelvis with simultaneous integrated boost to macroscopic disease in a cohort of elderly patients. Materials and Methods: Inclusion criteria of this prospective study were age ≥70 years, Karnofsky performance status 70 to 100, locally advanced histologically proven squamous cervical carcinoma, and patients unable to undergo brachytherapy. Radiation doses prescribed were 66 Gy to the macroscopic disease and 54 Gy to the pelvic nodes in 30 fractions. Weekly cisplatin dose was 40 mg/mq. Results: A total of 30 patients were recruited. Median follow-up was 32 mo…