Ahmed Nabih Zaki Rashed

Work place: Electronics and Electrical Communication Engineering Department, Faculty of Electronic Engineering, Menouf 32951, Menoufia University, EGYPT

E-mail: ahmed_733@yahoo.com


Research Interests: Physics, Computational Physics


Dr. Ahmed Nabih Zaki Rashed was born in Menouf city, Menoufia State, Egypt country in 23 July, He received the B.Sc., M.Sc., and Ph.D. scientific academic engineering degrees in the Electronics and Electrical Communications Engineering Department from Faculty of Electronic Engineering, Menoufia University in 1999, 2005, and 2010 respectively, EGYPT. Currently, his job carrier is a scientific lecturer in Electronics and Electrical Communications Engineering Department, Faculty of Electronic Engineering, Menoufia university, Menouf. Postal Menouf city code: 32951, EGYPT.
His scientific master science thesis has focused on polymer fibers in optical access communication systems.Moreover his scientific Ph. D. thesis has focused onrecent applications in linear or nonlinear passive or active in optical networks. His interesting research mainly focuses on transmission capacity, a data rate product and long transmission distances of passive and active optical communication networks, wireless communication, radio over fiber communication systems, and optical network security and management. He has published many high scientific research papers in high quality and technical international journals in the field of advanced communication systems, optoelectronic devices, and passive optical access communication networks. His areas of interest and experience in optical communication systems, advanced optical communication networks, wireless optical access networks, analog communication systems, optical filters and Sensors, digital communication systems, optoelectronics devices, and advanced material science, network management systems, multimedia data base, network security, encryption and optical access computing systems. As well as he is editorial board member in high academic scientific International research Journals. Moreover he is a reviewer member in high impact scientific research international journals in the field of electronics, electrical communication systems, optoelectronics, information technology and advanced optical communication systems and networks. His personal electronic mail: ahmed_733@yahoo.com.

Author Articles
Rigorous Progress on Algorithms Based Routing and Wavelength Assignment in Trans-Egypt Network (TEGYNET) Management

By Abd El Naser A. Mohammed Ahmed Nabih Zaki Rashed Osama S. Fragallah Mohamed G. El Abyad

DOI: https://doi.org/10.5815/ijcnis.2013.02.08, Pub. Date: 8 Feb. 2013

In simple wavelength-division multiplexed (WDM) networks, a connection must be established along a route using a common wavelength on all of the links along the route. The introduction of wavelength converters into WDM cross connects increases the hardware cost and complexity. Given a set of connection requests, the routing and wavelength assignment problem involves finding a route (routing) and assigning a wavelength to each request. This paper has presented the WDM technology is being extensively deployed on point to point links within transport networks in the EGYPT. However, WDM promises advantages for switching and routing as well as for transmission. Optical cross connects are currently being developed which can switch an entire wavelength from an input fiber to an output fiber so that large bandwidth circuits can be routed through the network according to wavelength. High speed, fixed bandwidth, end to end connections called lightpaths can then be established between different nodes. Our suggested Trans-Egypt Network (TEGYNET) which uses optical cross connects to route lightpaths through the network are referred to as wavelength routing networks. The average setup time, average link utilization, traffic load, blocking probability, and achievable link utilization in the presence of both single path and multi math routing are the major interesting parameters in the design of TEGYNET topology.

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Current Trends of High capacity Optical Interconnection Data Link in High Performance Optical Communication Systems

By Ahmed Nabih Zaki Rashed

DOI: https://doi.org/10.5815/ijisa.2013.03.10, Pub. Date: 8 Feb. 2013

Optical technologies are ubiquitous in telecommunications networks and systems, providing multiple wavelength channels of transport at 2.5 Gbit/sec to 40 Gbit/sec data rates over single fiber optic cables. Market pressures continue to drive the number of wavelength channels per fiber and the data rate per channel. This trend will continue for many years to come as electronic commerce grows and enterprises demand higher and reliable bandwidth over long distances. Electronic commerce, in turn, is driving the growth curves for single processor and multiprocessor performance in data base transaction and Web based servers. Ironically, the insatiable taste for enterprise network bandwidth, which has driven up the volume and pushed down the price of optical components for telecommunications, is simultaneously stressing computer system bandwidth increasing the need for new interconnection schemes and providing for the first time commercial opportunities for optical components in computer systems. The evolution of integrated circuit technology is causing system designs to move towards communication based architectures. We have presented the current tends of high performance system capacity of optical interconnection data transmission link in high performance optical communication and computing systems over wide range of the affecting parameters.

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Recent Advances of Distributed Optical Fiber Raman Amplifiers in Ultra Wide Wavelength Division Multiplexing Telecommunication Networks

By Abd El Naser A. Mohammed Ahmed Nabih Zaki Rashed Mahmoud M. A. Eid

DOI: https://doi.org/10.5815/ijcnis.2012.04.08, Pub. Date: 8 May 2012

Recently, many research works have been focused on the fiber optic devices for optical communication systems. One of the main interests is on the optical amplifiers to boost a weak signal in the communication systems. In order to overcome the limitations imposed by electrical regeneration, a means of optical amplification was sought. The competing technology emerged: the first was Raman amplification. One reason was that the optical pump powers required for Raman amplification were significantly higher than that for Erbium doped fiber amplifier (EDFA), and the pump laser technology could not reliably deliver the required powers. However, with the improvement of pump laser technology Raman amplification is now an important means of expanding span transmission reach and capacity. We have deeply studied an analytical model for optical distributed Raman amplifiers (DRAs) in the transmission signal power and pump power within Raman amplification technique in co-pumped, counter-pumped, and bi-directional pumping direction configurations through different types of fiber cable media. The validity of this model was confirmed by using experimental data and numerical simulations.

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Radiation Damage Effects in Heterostructure Light Emitting Diodes (HLEDs) under Proton Irradiation Fields

By Ahmed Nabih Zaki Rashed

DOI: https://doi.org/10.5815/ijisa.2012.05.07, Pub. Date: 8 May 2012

In the present paper, we have been analyzed the high temperature variations testing in order to be used to determine light emitting diode lifetime, even though laser diode failure mechanisms are more sensitive to increases in current density. As a measured parameter of degradation, the current density is of great significance when searching for failure modes in a laser diode. Raising the current density however, is not really indicative of lifetime since it is more likely a situation to be avoided than one that simulates normal lifetime degradation. The reliability of semiconductor sources is very dependent on the degradation modes. This paper has investigated some of the degradation modes and capabilities of typical LEDs currently used in many communication and sensing systems over wide range of the affecting parameters. LED’s are typically used in multimode transmission systems where data rates no larger than 50 Mbit/sec are required. They have larger spectral widths and can add to the problem of dispersion in communications systems. Laser diodes are used in systems that require coherent and often single mode light such as high data rate communications and sensing applications.

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Under Water Optical Wireless Communications Technology for Short and Very Short Ranges

By Abd ElNaser A. Mohamed Ahmed Nabih Zaki Rashed Amina E. M. El-Nabawy

DOI: https://doi.org/10.5815/ijitcs.2012.05.07, Pub. Date: 8 May 2012

This paper has presented our interest in wireless underwater optical communications. Recent interest in ocean exploration has brought about a desire for developing wireless communication techniques in this challenging environment. Due to its high attenuation in water, a radio frequency (RF) carrier is not the optimum choice. Acoustic techniques have made tremendous progress in establishing wireless underwater links, but they are ultimately limited in bandwidth. In traditional communication systems, constructing a link budget is often relatively straight forward. In the case of underwater optical systems the variations in the optical properties of sea water lead to interesting problems when considering the feasibility and reliability of underwater optical links. The main focus of this paper is to construct an underwater link budget which includes the effects of scattering and absorption of realistic sea water. As well as we have developed the underwater optical wireless communication systems to have shorter ranges, that can provide higher bandwidth (up to several hundred Mbit/sec) communications by the assistant of exciting high brightness blue LED sources, and laser diodes suggest that high speed optical links can be viable for short range application.

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Very Large Scale Optical Interconnect Systems for Different Types of Optical Interconnection Networks

By Ahmed Nabih Zaki Rashed

DOI: https://doi.org/10.5815/ijcnis.2012.03.08, Pub. Date: 8 Apr. 2012

The need for scalable systems in market demands in terms of lower computing costs and protection of customer investment in computing: scaling up the system to quickly meet business growth is obviously a better way of protecting investment: hardware, software, and human resources. A scalable system should be incrementally expanded, delivering linear incremental performance with a near linear cost increase, and with minimal system redesign (size scalability), additionally, it should be able to use successive, faster processors with minimal additional costs and redesign (generation scalability). On the architecture side, the key design element is the interconnection network. The interconnection network must be able to increase in size using few building blocks and with minimum redesign, deliver a bandwidth that grows linearly with the increase in system size, maintain a low or (constant) latency, incur linear cost increase, and readily support the use of new faster processors. The major problem is the ever-increasing speed of the processors themselves and the growing performance gap between processor technology and interconnect technology. Increased central processing unit (CPU) speeds and effectiveness of memory latency-tolerating techniques.

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Ultra Wide Wavelength Multiplexing/Demultiplexing Conventional Arrayed Waveguide Grating (AWG) Devices for Multi Band Applications

By Abd El Naser A. Mohammed Ahmed Nabih Zaki Rashed Mahmoud M. A. Eid

DOI: https://doi.org/10.5815/ijisa.2012.02.02, Pub. Date: 8 Mar. 2012

This paper has proposed new materials based conventional arrayed waveguide grating (AWG) devices such as pure silica glass (SiO2), Lithium niobate (LiNbO3) , and gallium aluminum arsenide (Ga(1-x)Al(x)As) materials for multiplexing and demultiplexing applications in interval of 1.45 μm to 1.65 μm wavelength band, which including the short, conventional, long, and ultra long wavelength band. Moreover we have taken into account a comparison between these new materials within operating design parameters of conventional AWG devices such as diffraction order, length difference of adjacent waveguides, focal path length, free spectral range or region, maximum number of input/output wavelength channels, and maximum number of arrayed waveguides. As well as we have employed these materials based AWG to include Multi band applications under the effect of ambient temperature variations.

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