Kamal Ghoumid

Wavelength-Selective Ti:LiNbO

This paper described a wavelength-selective couplers dedicated to drop functionality (spectral-selective couplers dedicated to wavelength demultiplexing). It is consist of two Y junctions: an input two drop channels and an output. The Y-branches distributors of optical power were carried out by a specific geometry of Ti:LiNbO3 waveguides. Each Y junction is composed by two identical bends jointed at one with a weak inclination angle to decrease losses. On each arm of the Y-branches, a Bragg grating (BG) is etched by Focused Ion Beam (FIB) in order to extract a specific wavelength band. A two-channel configuration is adopted which demonstrate a drop functionality of two spectral bands centered at 1123 nm and 1527 nm. The complementary spectrum is avalaible at the coupler output.

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In this paper we propose an efficient technique for micromachining lithium niobate that is used in Ti-diffused waveguides. The use of Focused Ion Beam (FIB) etching allows obtaining homogeneous periodic microstructures. Bragg gratings with a period of 1.05 μm and an aspect ratio of 6:1 (depth-to-half period ratio) have been achieved. A reflectivity greater than 95 % associated with a bandwidth at half maximum of about 100 nm within a window centered at 1550 nm, is demonstrated for a Bragg grating of period Λ = 1.8 μm and a length of 144 μm, in good agreement with theoretical predictions.

Multiple Y-Branch Coupler Based on Focused Ion Beam Milled Bragg Reflectors

The realization of a Fabry-Pérot (F-P) cavity based on a Ti:LiNbO3 optical waveguide obtained by using a concept which consists of milling the Bragg gratings (BGs) in the cavity by the focused ion beam technique is shown in this letter. This F-P cavity is formed by two BGs which represent the two reflecting mirrors of the interferometer. The length of the cavity is defined by the distance between the two BGs. Thirty-one peaks and a free spectral range (FSR)=1.75 nm have been experimentally obtained in the range of wavelengths [1505-1548] nm. The experimental results are in accordance with those of theory. The fabrication process, the experimental results, as well as improvements to increase finesse F and FSR are discussed.

Optical Performance of Bragg Gratings Fabricated in Ti:LiNbO

Numerous applications in integrated optics, especially those related to multiwavelength telecommunications, require dichroic reflectors for use as narrowband or broadband wavelength-selective filters. Bragg mirrors are excellent candidates for this purpose, and we describe a method of fabricating Bragg grating reflectors in Ti-indiffused Lithium Niobate single-mode waveguides based on holographic masking in association with proton exchange. The holographic setup is employed to record a photolithographic mask directly on the substrate, enabling the inscription of waveguides with both periodic and aperiodic distributed parameters.

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In this paper, the authors propose a novel real-time study metrics of Round Trip Time (RTT) for Multi-Hop Wireless Mesh Networks. They focus on real operational wireless networks with fixed nodes, such as industrial wireless networks. The main aim of the metric is to show the effect of the Downlink and Uplink message size (DMS and UMS) on RTT with and without Forward Error Correction (FEC), user data size without any headers, on RTT path between a source (Supervisory Control and Data Acquisition (SCADA) center) and a destination RTU (Remote Terminal Units). The metric assigns weights to links based on the RTT path of a packet size over the link path. They studied the performance of the metric by implementing it in three wireless scenarios consisting of 3, 4 and 5 nodes; each node represents a wireless radio IP router. They find that in a multi-hops environment, the real-time metric clearly shows the impact of DMS, UMS and FEC on RTT by making judicious use of the number of the hops.

Waveguides by Focused Ion Beam Milling

The number of nodes in wireless sensor networks (WSNs) is one of the fundamental parameters when it comes to developing an algorithm based on Network Coding (NC) with LDPC (Low Density Parity Check) code because it directly affects the size of the generator matrix of the LDPC code and to its dispersion. Optimizing Wireless Communication Systems by decreasing BER (Bit Error Rate) is one approach to analyze the network into clusters (at the level of their nodes). In this paper, the authors present a fully distributed clustering algorithm and they consider different node values by cluster, then they select the curves that have the best compromise. They examine the effects of SNR (Signal-to-noise ratio) quantization on system performance obtained for different scenarios (by varying the parameter corresponding to the number of the symbol during the forwarding phase). Finally, the results prove that the increased number nodes improve LDPC code properties.

Technological Implementation Fabry–Pérot Cavity in

In this paper, we focus on efficient method for improving the reliability of data retransmission in real operational wireless communications. We analyze the effects of ACK (Acknowledge) and FEC (Forward Error Correction) on practical transmission performance of different message sizes. We propose a novel idea which allows quantifying and qualifying the reliability improvement in the network remote performance by exploiting Payload bitrate and forwarding time versus average message size with/without ACK/FEC respectively.

{\rm Ti}{:}{\rm LiNbO}_{3}

Command and control in real time of renewable energy are a fast-growing trend. The development of communication platform uses energy management software (Power studio technology) as a basis design for an overall system. The proposed prototype constructs Power Quality Analyzer. The main central control system will acquire data from the remote renewable energy system. All necessary monitor data include Voltage events and variations, Flicker, Harmonics, Unbalance and other control parameters will be stored in a control unit. Monitoring data is monitored as real-time data across Wireless Communication Systems using router in bridge mode to connect multiple devices wirelessly at the Power Quality Analyzer. This paper presents the metric application of Power Quality command and control systems for smart renewable energy power of useful Information. The authors approve that the metric application, Payload bitrate/forwarding time vs average message size, offers a remarkable flexibility results and gives a quick and easy idea of the possible Bitrate/Time in the wireless bridge network performance.

Waveguide by FIB

The Traffic matrix Estimation of IP networks has become a research topic in this later 10 years, where several methods have been used to resolve this ill posed problem. This paper deals with the later and presents a comparison study on training algorithms in Artificial Neural Networks (ANN) method, namely the BFGS Quasi-Newton; the Levenberg-Marquardt and Bayesian Regularization algorithms, which yields us accurate results as outputs, the comparison between them is made on estimating the error robustness, execution time and regression. It appears that the Levenberg-Marquardt algorithm performs the best results. We have used a real data from the American well known IP Network, called the Abilene network, to validate and evaluate our comparison, our implementation shows that the chosen algorithm has earned the challenge and ensure the smallest error in the shortest time and the estimated matrix is perfect..

Bragg mirror inscription on LiNbO 3 waveguides by index microstructuration

This paper shows the potentials of Network Coding (NC) for improvement of Round Trip Time (RTT) in practical wireless Narrowband RF communications (for remote monitoring of broadcasting Television and radio FM station). We illustrate how RTT changes versus number of hops using narrow band radios modem & Routers (RipEX unit), as a means of transmission between source and destination. As well as, we will illustrate the effect of Forward Error Correction (FEC) on the RTT. The measurements and simulations results show that the applying of NC significantly improves RTT.