The Experts below are selected from a list of 22401 Experts worldwide ranked by ideXlab platform
Amin Malekmohammadi - One of the best experts on this subject based on the ideXlab platform.
-
performance enhancement of mapping Multiplexing Technique utilising dual drive mach zehnder modulator for metropolitan area networks
Iet Optoelectronics, 2015Co-Authors: Mohamed A. Elsherif, Amin MalekmohammadiAbstract:A methodology to control the eye opening distribution of mapping Multiplexing Technique (MMT) system is proposed and presented. The authors modelled and analysed a method to enhance the receiver sensitivity of MMT system by using optimised dual-drive Mach–Zehnder modulator. The proposed method offers larger eye opening for distorted Level-3 eyes. Based on the numerical calculation, the optimisation leads toward minimal eye closure. The performance of proposed system is shown to be improved by 6.1 dB in terms of receiver sensitivity compared with the conventional MMT system. Throughout the paper, the authors also discuss a numerical comparative analysis between the proposed MMT model, conventional MMT model, 33% return-to-zero on–off-keying (33%RZ-OOK), 50% RZ-OOK, 67% carrier-suppressed RZ-OOK and 4-ary amplitude shift keying in terms of positive chromatic dispersion tolerance and spectral efficiency.
-
Power Efficiency Evaluation of Mapping Multiplexing Technique and Pulse Amplitude Modulation for Noncoherent Systems
IEEE Photonics Journal, 2015Co-Authors: Mohamed A. Elsherif, Amin MalekmohammadiAbstract:The two-, three-, and four-channel mapping Multiplexing Technique (MMT) is demonstrated to increase the data capacity of multilevel intensity-modulated transmission formats to 2, 3, and 4 bits/symbol with a substantial reduction in power penalty. This paper outlines the $N$ -channel MMT design metric consideration influence on the performance enhancement of higher order amplitude modulated systems in terms of power penalty, receiver sensitivity, and spectral efficiency. The signal space model has been developed for $N$ -channel MMT, where the average electrical and optical power expressions are derived. Transmission of 2, 3, and 4 bits/symbol using MMT system shows better performance in terms of the average optical power penalty, in comparison with pulse amplitude modulation (M-PAM) formats, with respect to the information capacity. The proposed scheme can be considered as an alternative to M-PAM systems with enhanced power efficiency.
-
Performance improvement of Mapping Multiplexing Technique (MMT) using Dual-Drive Mach-Zehnder Modulator at 40 Gb/s
2014 23rd Wireless and Optical Communication Conference (WOCC), 2014Co-Authors: Mohamed A. Elsherif, Amin MalekmohammadiAbstract:A methodology to control the eye opening distribution of Mapping Multiplexing Technique (MMT) system is proposed and presented. We modeled and analyzed a method to enhance the receiver sensitivity of MMT system by using optimized Dual-Drive Mach-Zehnder Modulator (DD-MZM). The proposed method offers larger eye opening for distorted higher-level eyes. Based on the numerical calculation, the optimization leads towards minimal eye closure in comparison to conventional MMT system. In comparison to the conventional MMT system, the optimization leads in to the 6.1 dB improvement in terms of receiver sensitivity.
-
absolute polar duty cycle division Multiplexing apdcdm Technique for wireless communications
International Conference on Computer and Communication Engineering, 2008Co-Authors: Amin Malekmohammadi, M K Abdullah, Ghafour Amouzad Mahdiraji, A F Abas, M MokhtarAbstract:A new Multiplexing and deMultiplexing Technique for wireless communications which is called Absolute Polar Duty Cycle Division Multiplexing (APDCDM) is presented in this paper. APDCDM can become an alternative Multiplexing Technique in wireless communications. The new Technique allows for better error detection, correction, clock recovery and more efficient use of time slots as well as spectrum. The principle of the APDCDM Technique has been discussed in this paper based on theoretical analysis as well as simulation studies. The performance comparison is made against time division Multiplexing Technique (TDM). The simulation has been set for wireless transmission, based on free space propagation model with adaptive white Gaussian noise (AWGN); QAM is used as modulation scheme to evaluate this Technique against data rate and number of users. The simulation result correspond with the theoretical study show that APDCDM has better performance than TDM for supporting higher number of Multiplexing users and bit rate.
Ivan B. Djordjevic - One of the best experts on this subject based on the ideXlab platform.
-
Physical-Layer Security in Orbital Angular Momentum Multiplexing Free-Space Optical Communications
IEEE Photonics Journal, 2016Co-Authors: Xiaole Sun, Ivan B. DjordjevicAbstract:The physical-layer security of a line-of-sight (LOS) free-space optical (FSO) link using orbital angular momentum (OAM) Multiplexing is studied. We discuss the effect of atmospheric turbulence to OAM-multiplexed FSO channels. We numerically simulate the propagation of OAM-multiplexed beam and study the secrecy capacity. We show that, under certain conditions, the OAM Multiplexing Technique provides higher security over a single-mode transmission channel in terms of the total secrecy capacity and the probability of achieving a secure communication. We also study the power cost effect at the transmitter side for both fixed system power and equal channel power scenarios.
W H Chung - One of the best experts on this subject based on the ideXlab platform.
-
fiber laser based wavelength division multiplexed fiber bragg grating sensor system
IEEE Photonics Technology Letters, 2001Co-Authors: Youlong Yu, W H ChungAbstract:A wavelength-division-Multiplexing Technique for interrogating 10-cascaded fiber Bragg grating sensing elements based on a ring-compounded-cavity fiber laser is reported. A feedback control Technique was introduced to a tunable Fabry-Perot filter that tracks the wavelength-shift of the sensor. The sensors were demodulated using an unbalanced scanning Michelson interferometer and a sensitivity of 1.682/spl deg///spl mu//spl epsi/ has been demonstrated.
Jordi Mompart - One of the best experts on this subject based on the ideXlab platform.
-
free space optical polarization de Multiplexing and Multiplexing by means of conical refraction
arXiv: Optics, 2013Co-Authors: Alex Turpin, Todor K. Kalkandjiev, Yurii V. Loiko, Jordi MompartAbstract:Polarization de-Multiplexing and Multiplexing by means of conical refraction is proposed to increase the channel capacity for free space optical communication applications. The proposed Technique is based on the forward-backward optical transform occurring when a light beam propagates consecutively along the optic axes of two identical biaxial crystals with opposite orientations of their conical refraction characteristic vectors. We present experimental proof of usefulness of the conical refraction de-Multiplexing and Multiplexing Technique by increasing in one order of magnitude the channel capacity at optical frequencies in a propagation distance of 4m.
-
free space optical polarization deMultiplexing and Multiplexing by means of conical refraction
Optics Letters, 2012Co-Authors: Alex Turpin, Todor K. Kalkandjiev, Yurii V. Loiko, Jordi MompartAbstract:Polarization deMultiplexing and Multiplexing by means of conical refraction is proposed to increase the channel capacity for free-space optical communication applications. The proposed Technique is based on the forward-backward optical transform occurring when a light beam propagates consecutively along the optic axes of two identical biaxial crystals with opposite orientations of their conical refraction characteristic vectors. We present an experimental proof of usefulness of the conical refraction deMultiplexing and Multiplexing Technique by increasing in one order of magnitude the channel capacity at optical frequencies in a propagation distance of 4 m.
Tengyun Chen - One of the best experts on this subject based on the ideXlab platform.
-
long distance transmission of quantum key distribution coexisting with classical optical communication over a weakly coupled few mode fiber
Optics Express, 2020Co-Authors: Bixiao Wang, Yingqiu Mao, Lei Shen, Lei Zhang, Xiaobo Lan, Yuyang Gao, Yanlin Tang, Shibiao Tang, Jun Zhang, Tengyun ChenAbstract:Quantum key distribution (QKD) is one of the most practical applications in quantum information processing, which can generate information-theoretical secure keys between remote parties. With the help of the wavelength-division Multiplexing Technique, QKD has been integrated with the classical optical communication networks. The wavelength-division Multiplexing can be further improved by the mode-wavelength dual Multiplexing Technique with few-mode fiber (FMF), which has additional modal isolation and large effective core area of mode, and particularly is practical in fabrication and splicing technology compared with the multi-core fiber. Here, we present for the first time a QKD implementation coexisting with classical optical communication over weakly-coupled FMF using all-fiber mode-selective couplers. The co-propagation of QKD with one 100 Gbps classical data channel at -2.60 dBm launched power is achieved over 86 km FMF with 1.3 kbps real-time secure key generation. Compared with single-mode fiber using wavelength-division Multiplexing, given the same fiber-input power, the Raman noise in FMF using the mode-wavelength dual Multiplexing is reduced by 86% in average. Our work implements an important approach to the integration between QKD and classical optical communication and previews the compatibility of quantum communications with the next-generation mode division Multiplexing networks.
