Rachid Hamdi

Rachid Hamdi
Université 8 mai 1945 - Guelma · Department of Electronics and Telecommunications

Prof. (Dr.), Université 8 mai 1945 Guelma - Algeria/Télécom SudParis/Université Paris6 UPMC

About

45
Publications
10,544
Reads
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82
Citations
Citations since 2016
25 Research Items
33 Citations
201620172018201920202021202201234567
201620172018201920202021202201234567
201620172018201920202021202201234567
201620172018201920202021202201234567
Additional affiliations
January 2012 - present
Université 8 mai 1945 - Guelma
Position
  • Head of Department

Publications

Publications (45)
Article
Full-text available
We demonstrate that in addition to their role in tuning the wavelength of an N-stage hybrid liquid-crystal Šolc filter, liquid-crystal cells can also be used to vary the transmission bandwidth of such filter around any of the tuned wavelength. This bandwidth tuning is based on the variation of the number of stages by what we call here an “optical c...
Article
Full-text available
We propose the design of a multi-channel amplitude-equalizing polarization interference filter based on stacked liquid crystal birefringent blocks. Each block, which is optimized to control a predefined wavelength channel, consists of three components. The wavelength blocking/transmitting and the equalizing actions are provided by the liquid crysta...
Conference Paper
Full-text available
A novel 1times2 wavelength routing switch is introduced and analyzed. It is based on a tunable hybrid liquid-crystal Solc filter and a polarization beamsplitter. The device can be set into the bar state for an arbitrary subset of WDM channels while remaining in the cross state for the rest of channels. This is achieved via a tuning voltage applied...
Article
Full-text available
We demonstrate that the birefringence of the liquid-crystal cell (LCC) can be varied by applying different frequency values of a single applied ac square voltage. For the experimental evaluation of the birefringence, associated with a certain wavelength λ, as a function of the frequency F LCC of the electrical signal applied to the LCC, we use, for...
Conference Paper
Time-to-frequency mapping is induced on an arbitrary optical pulse by XPM using a parabolic pump pulse. The new derived condition of the peak pump pulse allows the conversion of the input pulses having different durations.
Article
Full-text available
In this paper, the proficiency of nonlinearity compensation studied on the polarization division multiplexing 0.3 return-to-zero quadrature phase-shift keying (PDM-0.3RZ-QAM) coherent optical system. The considerable nonlinear effect is the self-phase modulation (SPM) in the presence of chromatic dispersion. The nonlinearity mitigation technique ba...
Poster
Full-text available
In this work, we present a new simple method to synthesize a temporal pulse shaper using non-identical birefringent crystals. The shaper generates 2N sub-pulses to produce any temporal pulse shapes with high efficiency and fidelity. An optimization algorithm is used to optimize the amplitude of each sub-pulse and the specific time delay between the...
Conference Paper
We propose a pulse rate multiplier based on the temporal Talbot effect using a phase-only birefringent optical filter. The Opto-geometrical parameters of the filter are obtained by an optimization algorithm to achieve the desired spectral response. Preliminary results show excellent agreement with those anticipated by theory.
Conference Paper
We present a new simple method to synthesize a temporal pulse shaper using non-identical birefringent crystals. The shaper configuration consists of N crystal with appropriate length and orientation placed between a polarizer and an analyzer. The Opto-geometrical shaper parameters are achieved by an optimization algorithm. This shaper is capable of...
Article
Full-text available
In this paper, we propose a tailored dual polarization encryption scheme (T-DPES) based on a polarization encoding of input target images into a same predefined uniformly distributed noisy output image, using Mueller–Stokes's formalism. The optical encryption setup, based on a polarizer and a pixelated polarizer, uses a random image key as a first...
Article
Full-text available
In this paper, we propose a novel approach to implement a pulse rate multiplier based on the temporal self-imaging effect using, for the first time to our knowledge, a birefringent optical filter. The proposed filter, with periodic quadratic phase-only filtering induced through engineered polarization mode dispersion, contains 𝑁-stage hybrid birefr...
Conference Paper
We propose a frequency multiplying technique of a given periodic laser pulse train based on the temporal self-imaging effect using a birefringent filter which has a continuous quadratic phase over the operation bandwidth. An optimization algorithm is used to determine the opto-geometrical parameters of the filter to achieve the desired spectral res...
Conference Paper
We propose a Tailored DPES based on a tailored pixelated polarizer to encrypt target images into a predefined uniformly distributed noisy image. Relying on Mueller–Stokes formalism, it provides more robustness and flexibility than DPES
Article
In this paper, we demonstrate the efficiency of Electronic Dispersion Compensation (EDC) for coherent optical systems based on Polarization Division Multiplexed Quadrature Phase Shift Keying (PDM-QPSK). The performance of the proposed system is tested using a pulse that has been recently used in the presence of nonlinear effects.The proposed system...
Article
We propose a new method for the synthesis of arbitrary temporal output pulse profiles by using a birefringent laser pulse shaper. This shaper contains a series of N birefringent crystals placed between an input and output polarizers. The synthesis method starts with the LTI system theory to determine the optimal amplitudes of the replica pulses at...
Article
This paper investigates the performance of 5.12 Tbps Dense Wavelength-Division Multiplexing (DWDM) transmission using 40 channels with 128-Gbps Polarization Division Multiplexing-0.3 return to zero-quadrature phase-shift keying Quadrature Phase Shift Keying (PDM-0.3RZ-QPSK) modulation format. The prime advantage of the proposed work is improving th...
Article
Full-text available
The transmission performance of ultra-high capacity up to 1.28 Tbps dense wavelength division multiplexing system for Non-Return to Zero (NRZ) and Return to Zero (RZ) modulation formats have been analyzed in this work. The transmission of 64-channels has been achieved over the 50 km × N Span of optical linkin200, 100, and 50 GHz channel spacing. Th...
Conference Paper
The huge capacity of the coherent optical systems is restricted by fiber nonlinearity. Using digital signal processing algorithms has the opportunity to reduce this limitation. In this work, we investigate the compensation of fiber nonlinearities by digital backpropagation in both Polarization-division-multiplexed 16-level quadrature amplitude modu...
Conference Paper
Full-text available
In this work, we present a method for the synthesis of a birefringant shaper having arbitrarily ouptput pulse profiles. The shaper configuration consists of N birefringent crystals placed between a polarizer and an analyzer. The optogeometrical shaper parameters are obtained by the resolution of generalized nonlinear equation systems based on time-...
Conference Paper
Full-text available
In this paper we present a key configuration of birefringent filter structure that can be used for many optical applications such as a birefringent filtering, dispersion compensation and laser pulse shaping. The configuration consists of N hybrid stages placed between a polarizer and an analyzer, with each hybrid stage containing a birefringent pla...
Conference Paper
Full-text available
In this paper, we present a novel approach to analyze Distributed Feedback semiconductor laser with weak external optical feedback. This approach is based on Time Domain Traveling Wave Model, which extends by introducing two new fields equations in time domain to include the deviation of the forward and backward traveling optical fields as a result...
Conference Paper
Full-text available
We demonstrate a birefringent pulse shaper generating arbitrarily optimal temporal pulse profiles. The optogeometrical shaper parameters are obtained by a resolution of generalized nonlinear equation system based on time-domain Jones matrix formalism
Conference Paper
Full-text available
In this paper, we present a rigorous approach based on split-step time-domain dynamic modeling (SS-TDM) algorithm using to solve the time-dependent coupled wave equations of the time-domain traveling-wave (TDTW) model to investigate the effect of facets reflectivity on the Light-Current characteristics of (DFB) semiconductor laser for different val...
Conference Paper
Full-text available
This paper investigates the static characteristics of a multiple-phase-shift (MPS) distributed feedback DFB semiconductor laser with a distributed coupling coefficient (DCC) based on modified split-step time-domain modeling (SS-TDM) used for solving the time-dependent coupled-wave equations of time domain traveling wave (TDTW) model. The simulation...
Article
Full-text available
We propose a novel semiconductor laser structure. It is composed of three cascaded active sections: a Fabry-Pérot laser section sandwiched between two gain-coupled distributed feedback (DFB) laser sections. We have modeled this multi-section structure. The simulation results show that compared with index- and gain-coupled DFB lasers, a significant...
Article
Full-text available
We propose a novel semiconductor laser structure. It is composed of three cascaded active sections: a Fabry-Pérot laser section sandwiched between two gain-coupled distributed feedback (DFB) laser sections. We have modeled this multi-section structure. The simulation results show that compared with index- and gain-coupled DFB lasers, a significant...
Conference Paper
Full-text available
We present a time-domain traveling wave model (TDTWM) for the simulation of Fabry-Pérot laser output spectrum. We present examples of simulation of the spectrum for different drive current and facets reflectivity. The output spectrum found by the TDTWM shows an excellent agreement with the spectrum obtained by rate equations for below and at thresh...
Conference Paper
In this paper, we present a novel procedure for the synthesis of a hybrid liquid-crystal birefringent filter (HLCBF) having arbitrarily amplitude transmittance. The synthesis procedure is based on the resolution of a generalized nonlinear equation system directly deducted from a Jones matrix formulation. A typical example of a 6-stage HLCBF having...
Conference Paper
Full-text available
In this paper we propose a new approach to study the relative intensity noise RIN of Fabry-Pérot laser based on traveling wave model TWM. The intensity is modeled for both high and low frequency noise for different injection current. Numerical results of our modeling show an excellent agreement with the rate equations model in the calculation of RI...
Conference Paper
Full-text available
Nous exposons un algorithme de synthèse d'un filtre biréfringent hybride à cristaux liquides dont la fonction de transmission peut être de forme quelconque, ce qui conduit à des coefficients qui seront en général complexes. Cette méthode de synthèse offre par conséquent une grande liberté dans le choix de la fonction de transfert pour les systèmes...
Article
Full-text available
We propose and demonstrate a new modified Lyot filter to independently ensure the channel amplitude equalization and the bandwidth tuning functions. The device consists of hybrid liquid crystal interferometers. We show numerically and experimentally that for a modified four-stage Lyot filter, the two first interferometers ensure equalization functi...
Article
Full-text available
We experimentally demonstrate the feasibility of the bandwidth tuning of a liquid-crystal based bandpass Lyot filter. This bandwidth tuning is achieved by applying a voltage to vary the birefringence of the liquid-crystal cells whose optical path difference takes predefined discrete values. We show that for a 2-stage liquid-crystal Lyot filter and...
Presentation
Full-text available
We experimentally demonstrate the feasibility of the bandwidth tuning of a liquid-crystal based bandpass Lyot filter. This bandwidth tuning is achieved by applying a voltage to vary the birefringence of the liquid-crystal cells whose optical path difference takes predefined discrete values. We show that for a 2-stage liquid-crystal Lyot filter and...
Conference Paper
Full-text available
Nous démontrons la faisabilité de reconfigurer la bande passante à mi-hauteur, autour d'une longueur d'onde particulière, d'un filtre de Lyot constitué exclusivement d'étages à cristaux liquides. Cette reconfiguration est réalisée au moyen de cellules à cristaux liquides dont la biréfringence varie lorsqu'une tension électrique est appliquée. Les t...
Article
Full-text available
We propose and demonstrate a novel optical imple- mentation to simultaneously improve the contrast and increase the finesse of a classical -stage Lyot filter. The new device based on the multiple-passage concept uses two mirrors placed at the ex- tremities of the filter. The light beam passes through the structure back and forth and each passage ha...
Conference Paper
Full-text available
The knowledge of the detailed structure of the scatterer using synthetic aperture radar (SAR) can only be possible if a complete description of the scene was available, which is impossible in practice. Therefore, it is necessary to average data to obtain estimates of useful precision. The statistical description presents a great interest since it a...
Article
Full-text available
The knowledge of the detailed structure of the scatterer using synthetic aperture radar (SAR) can only be possible if a complete description of the scene was available, which is impossible in practice. Therefore, it is necessary to average data to obtain estimates of useful precision. The statistical description presents a great interest since it a...
Conference Paper
Full-text available
One of the most important functionality in any optical network is the filtering function. High performances devices dedicated to this function are desirable, especially for DWDM (Dense wavelength Division Multiplexing) configurations. The optical filters must be adapted to the high density spectrum, and so, have a high contrast (over 40dB) and a Fu...
Article
Full-text available
This paper discusses the design of a wavelength blocker/channel equalizer (WB/CE) based on stacked liquid-crystal birefringent blocks. Each block, which is optimized to control a predefined channel wavelength, consists of three components. The wavelength blocking/transmitting and the equalizing actions are provided by the liquid-crystal cell (LCC)...
Thesis
Full-text available
The evolution of the optical network to meshed architecture led to the need to design and deploy reconfigurable optical add/drop multiplexers (ROADM) as routing nodes. The design complexity of such devices has a direct impact on their manufacturing cost. The aim of this thesis is to propose a low cost fully reconfigurable solution. We have chosen l...
Presentation
Full-text available
A novel 1×2 wavelength routing switch is introduced and analyzed. It is based on a tunable hybrid liquid-crystal Solc filter and a polarization beamsplitter. The device can be set into the bar state for an arbitrary subset of WDM channels while remaining in the cross state for the rest of channels. This is achieved via a tuning voltage applied to l...
Article
Full-text available
An electro-optically tunable erbium-doped fiber ring laser with a side mode suppression ratio of ~ 51.2 dB and a 0.062 nm linewidth is demonstrated. Wavelength tuning is achieved with a hybrid liquid crystal Solc structure used as an intracavity tunable filter. The laser wavelength is tuned over 28.6 nm with a tuning rate of 2.38 nm/V.
Article
Full-text available
This paper presents an efficient hybrid method namely spectral domain approach (S.D.A) for the analysis of dispersion characteristics of microstrip lines. The analysis is based on the Green's functions/moment method, where the electric-field integral equation, representing the boundary conditions that the total field must vanish on the perfect elec...

Questions

Question (1)
Question
I am looking for the Non linear optical parameters of Calcite and Quartz crystals in the telecom window (1.2 - 1.7 micrometer).

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Projects

Projects (2)
Project
Les progrès dans les télécommunications optiques sont alimentés par une explosion de nouveaux services et applications. Comme on s’approche de la capacité théorique de la fibre optique dans les réseaux longues distances et métropolitains, les acteurs du marché des télécommunications utilisent désormais des technologies qui semblaient impossibles il y a quelques années et ne ménagent aucun effort pour répondre aux exigences en bande passante dans les réseaux d'accès. Pendant ce temps et pour de nombreux pays, garantir des communications large-bandes pour presque tous les foyers est un but en soi. La couche optique dans les réseaux gagne plus d'intelligence qui induira une plus grande efficacité et améliorera les services, mais il en résulte aussi une plus grande complexité dans le fonctionnement du réseau. Au niveau des réseaux d'accès, les opérateurs cherchent, à terme, une évolution vers des plates-formes d'accès avec allocation flexible de bande passante ainsi que des PON utilisant des formats de modulation avancés, de l’amplification optique sensible à la phase et des techniques de la détection cohérente. Par ailleurs, les réseaux de transport sont en constante évolution en réponse à l'augmentation incessante du trafic et les innovations dans les services. Le déploiement des ROADM Multi-degrés et la normalisation des systèmes WDM à grille flexible permet une meilleure efficacité spectrale en raison de l'affectation de la bande passante du canal aux données de transport demandées. Néanmoins, des efforts sont nécessaires pour étudier son impact sur les performances du système, le routage, la transmission et les technologies des composants et dispositifs correspondants. Aussi, un intérêt mondial est porté sur le contournement des limites de capacité des fibres optiques actuelles en développant radicalement de nouvelles formes de fibres de transmission, en particulier des fibres multi-cœurs et des fibres multi-modes destinées au multiplexage par répartition spatiale en conjonction avec des amplificateurs opérants en dehors de la bande C et L. Cela pourrait augmenter sensiblement le nombre de canaux d'information dans un seul brin de fibre, ce qui nécessite de nouvelles approches pour la conception, la fabrication et la caractérisation de ces fibres, des sources Lasers et des amplificateurs.