Faculty Electronic Engineering

Minūf, Egypt

Faculty Electronic Engineering

Minūf, Egypt

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Mohamed A.E.-N.A.,Faculty Electronic Engineering | Ayad N.A.,Egypt Atomic Energy Authority | Rashed A.N.Z.,Faculty Electronic Engineering | El-Hageen H.M.,Faculty Electronic Engineering | El-Hageen H.M.,Egypt Atomic Energy Authority
Nonlinear Optics Quantum Optics | Year: 2011

In the present paper we have been investigated the harmful neutrons and thermal effects on soliton transmission bit rates of vertical cavity surface emitting lasers (VCSELs) based different materials such as aluminum gallium arsenide (AlGaAs), and polymer over wide range of the affecting parameters. Thermo-irradiated penalties were computed and fitted as nonlinear relationships of useful impact in the design model for the device. Analysis of laser characteristics after irradiation showed that the main effect of radiation damage is an increase in bulk recombination that increases loss within the laser cavity. The device performance degradation is proportional to the fluence. Both the ambient temperature and irradiation dose as well as the spectral wavelength possess serve reduction effects on the transmission characteristics (dispersion, and bandwidth) and consequently the transmitted bit rates and products. The fluence rate is also relevant for degradation in electron irradiation. Low fluence rate leads to larger degradation compared to those associated with high fluence rate resulting from heat impact in bulk. The radiation damage of neutron is larger than irradiation damage of electron, which is caused by the difference in mass and the possibility of nuclear collision for the formation of lattice defects. © 2011 Old City Publishing, Inc.


Mohamed A.E.-N.A.,Faculty Electronic Engineering | Ayad N.A.,Egypt Atomic Energy Authority | Rashed A.N.Z.,Faculty Electronic Engineering | El-Hageen H.M.,Faculty Electronic Engineering | El-Hageen H.M.,Egypt Atomic Energy Authority
Advanced Science Letters | Year: 2012

In the present paper, we have been investigated deeply and parametrically the speed response of Si PIN photodiodes employed in high temperature-irradiated environment. The radiation-induced photodiodes defects can modify the initial doping concentrations, creating generation-recombination centres and introducing trapping of carriers. Additionally, rate of the lattice defects is thermally activated and reduces for increasing irradiation temperature as a result of annealing of the damage. Nonlinear relations are correlated to investigate the current-voltage and capacitance-voltage dependences of the Si PIN photodiodes, where thermal and gamma irradiation effects are considered over the practical ranges of interest. Both the ambient temperature and the irradiation dose possess sever effects on the electro-optical characteristics and consequently the photo-response time and SNR of Si PIN photodiodes. In this paper, we derive the transient response of a Si PIN photodiode for photogeneration currents, when it is exposed to gamma radiation at high temperature. An exact model is obtained, which may be used to optimize the responsivity and speed of these irradiated devices over wide range of the affecting parameters. © 2012 American Scientific Publishers. All rights reserved.


Mohamed A.E.-N.A.,Faculty Electronic Engineering | El-Halawany M.M.,Faculty Electronic Engineering | El-Hageen H.M.,Faculty Electronic Engineering | El-Hageen H.M.,Egypt Atomic Energy Authority
Nonlinear Optics Quantum Optics | Year: 2010

In the present paper, they have analyzed deeply and parametrically the performance of PIN photodiodes employed in high temperature-irradiated environment. The radiation-induced photodiodes defects can modify the initial doping concentrations, creating generation-recombination centres and introducing trapping of signal charge carriers. Additionally, introduction rate of the lattice defects is thermally activated and decreases with increasing irradiation temperature as a result of annealing of the damage. The present work aims at a comparison of the behaviour of differently constructed Si and InGaAs PIN photodiodes after exposure to deferent conditions (ionizing gamma rays doses and electrons particles fluences respectively) of radiation with increasing temperature. Nonlinear relations are correlated to investigate the current-voltage and capacitance-voltage dependences based on the equivalent circuit of the PIN photodiodes where thermal and irradiation effects are considered. Thermal and irradiation effects are modelled and investigated over the practical ranges of interest. Both the ambient temperature and irradiation dose as well as the spectral power of incident light possess several effects on the electro-optical PIN photodiode characteristics (dark current, photocurrent, absorption coefficient, responsivity, quantum efficiency and directivity) and consequently SNR and BER for analog and digital optical link systems.

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