MOHAMED MOUSA SAYED EMAM AHMED

Mohamed Abouelatta;A. Zekry;Ahmed Shaker;Fathy Z. Amer;Roaa I. Mubarak

10/11/2023

https://www.sciencedirect.com/science/article/pii/S1364032123008997?dgcid=author

MOHAMED MOUSA SAYED EMAM AHMED

Abdelhalim Zekry; Ahmed Shaker; Mohamed Abouelatta; Fathy Z. Amer; Roaa I. Mubarak; Dalia S. Louis

08/02/2023

https://www.mdpi.com/1996-1073/16/4/1676

MOHAMED MOUSA SAYED EMAM AHMED

A. ZEKRY; MOHAMED ABOUELATTA; AHMED SHAKER; FATHY Z. AMER; ROAA I. MUBARAK

31/12/2022

https://wseas.com/journals/articles.php?id=7466

MOHAMED MOUSA SAYED EMAM AHMED

A. Zekry; Mohamed Abouelatta; Ahmed Shaker; Fathy Z. Amer; Roaa I. Mubarak

14/11/2022

https://ieeexplore.ieee.org/document/9938572

MOHAMED MOUSA SAYED EMAM AHMED

AHMED SHAKER; ABDELHALIM ZEKRY; MOHAMED ABOUELATTA

30/08/2022

https://www.mdpi.com/1996-1073/15/17/6326/htm

MOHAMED MOUSA SAYED EMAM AHMED

A. Zekry; Mohamed Abouelatta; Ahmed Shaker

03/08/2022

https://link.springer.com/chapter/10.1007/978-981-19-1607-6_60

MOHAMED MOUSA SAYED EMAM AHMED

Abdelhalim Zekry , Mohamed Abouelatta , Ahmed Shaker , Fathy Z. Amer , Roaa I. Mubarak

21/06/2022

https://www.mdpi.com/2073-4352/12/7/878

MOHAMED MOUSA SAYED EMAM AHMED

Fathy Z Amer; Roaa I Mubarak

01/02/2022

https://www.sciencedirect.com/science/article/abs/pii/S0030402621019604

MOHAMED MOUSA SAYED EMAM AHMED

F. Z. Amer; R. I. Mubarak

23/10/2021

https://ieeexplore.ieee.org/abstract/document/9600501

MOHAMED MOUSA SAYED EMAM AHMED

(F. Z. Amer, R. I. Mubarak)

13/10/2021

https://ieeexplore.ieee.org/abstract/document/9631919

MOHAMED MOUSA SAYED EMAM AHMED

MARWA SAYED SALEM BASYONI; AHMED SHAKER; ABDELHALIM ZEKRY, (Member, IEEE); MOHAMED ABOUELATTA; MOHAMMAD T. ALSHAMMARI; KAWTHER A. AL-DHLAN; AND CHRISTIAN GONTRAND

13/09/2021

https://ieeexplore.ieee.org/abstract/document/9541403

MOHAMED MOUSA SAYED EMAM AHMED

Fathy Z. Amer; Roaa I. Mubarak

01/09/2020

This paper presents a study of a tandem Perovskite/CIGS cell, its performance parameters, and the effect of temperature variations on these parameters. The variation of each sub-cell short-circuit current density value with absorption thickness of perovskite (top) sub-cell has been done to find the matching point, as the two sub-cells equivalent to two series cells. The combining of two sub-cells shows the ability to absorb photons spectrum up to 1120 nm and perform a conversion efficiency about 30.5% (at room temperature) higher than each sub-cell. The variation of temperature from 260 K up to 360 K shows that the power conversion efficiency decreases almost linearly from 33.5% to 26.6%. The validity of the proposed tandem cell is proved by comparing its results with the recent published results. The proposed tandem cell shows one of the highest power conversion efficiency relative to the recent published results.

MOHAMED MOUSA SAYED EMAM AHMED

Abdelrahman Afifi, M. Abouelatta-Ebrahim

01/11/2019

Generation of a high quality microwave signal based on optical electronic components using oscillation or using filtration have been investigated and implemented experimentally. The experimental results of signal generation using optoelectronic oscillator (OEO) are taken for three different long delay optical fiber lengths. The generated signal has a narrow bandwidth (less than 200 Hz) at carrier frequency of 2.31 GHz with phase noise less than −80 dBc/Hz at 1 kHz offset. Second proposed scheme to improve the quality of an RF signal is presented (optoelectronic Brillouin filter). The 6 dB linewidth of the filter output is reduced to sub hertz and the low frequency noise below 1 kHz is reduced about 10 dB. The scheme consists of a Brillouin-semiconductor optical amplifier (SOA), ring laser fitted with an RF intensity modulator and an APD detector. The optical loop acts as a cavity filter to the RF signal. A jitter in the cavity resonances due to temperature variations is completely eliminated from the output beat signal. There is a 10 dB increase in the phase noise at the FSR frequency and its harmonics. The setup is tested with signals generated by two different microwave sources and at frequencies up to 10 GHz, the limit of the used APD. Sources with RF linewidth less than the optical FSR produces one output mode with sub-hertz line width. For larger line width signals more than one RF frequency is produced, separated by the FSR, each showing the Brillouin linewidth proposed models for both systems are given.

MOHAMED MOUSA SAYED EMAM AHMED

Mohamed, Afifi, Abdelrahman, Abouelatta-Ebrahim, M

01/07/2018

An optoelectronic oscillator based on long fibre delay line to generate high stable microwave signal has been investigated and implemented experimentally. Mathematical model for this oscillator has been proposed. The experimental results are taken for different delay line lengths (2.1 Km, 4.2 Km and 6.6 Km respectively). The generated signal has a narrow bandwidth (less than 200 Hz) at carrier frequency 2.31 GHz and its phase noise is less than -80 dBc/Hz at 1 KHz offset. Comparison of the experimental results and analytical ones has been done. A critical length (Lc) concept of the used fibre delay line has been introduced as a design parameter for the proposed optoelectronic oscillator.

MOHAMED MOUSA SAYED EMAM AHMED

Abouelatta, Mohamed. Afifi, Abdelrahman E.

01/05/2018

Brillouin beam generation from a tuned pump laser source with large spectral width using double fiber loop mirror is proposed. Synthesize of a microwave signal using this simple technique is presented. This technique has been verified experimentally using a tunable laser source. The results show the generation of Brillouin beam using pump laser of output Power 15mW, and fiber loop mirror length 6.6 Km. Then the generated Brillouin beam is injected to the second loop to make a tunable Brillouin opto-electronic oscillator. The second loop consists of signal laser source, electro-optic modulator, 2 Km single mode fiber, optical detector and microwave amplifier (the microwave amplifier is introduced to achieve the required gain to start oscillation, as a result of the low allowed input power to thedetector used, which is 1 mw in this case). The output oscillation frequency is determined by the difference between the signal frequencies of the generated Brillouin beam and the signal laser source in the second loop.

MOHAMED MOUSA SAYED EMAM AHMED

Mahmoud H. Ahmed, Mohamed Abouelatta, and Abdelrahman E. Afifi

01/09/2016

An optical scheme to improve the quality of an RF signal is proposed. The 6 dB linewidth is reduced to sub hertz and the low frequency noise below 1 KHz is reduced about 10 dB. The scheme utilizes a Brillouin-semiconductor optical amplifier (SOA) ring laser fitted with an RF intensity modulator and an APD detector. The experimental results show cavity modes with FSR of 30.57 KHz due to Brillouin fiber length of 6.6 km and 6 dB bandwidth of 780 mHz typical of Brillouin lasers. The gain of the SOA balances out most of the losses in the ring mainly that due to the RF modulator. The modulated optical signal beats at the APD. The optical loop acts as a cavity filter to the RF signal. A jitter in the cavity resonances due to temperature variations is completely eliminated from the output beat signal. There is a 10 dB increase in the phase noise at the FSR frequency and its harmonics. The setup is tested with signals generated by different sources and to frequencies up to 10 GHz, the limit of the APD. Sources with RF linewidth less than the optical FSR produces one output mode with sub-hertz line width. For larger line width signals more than one RF frequency is produced, separated by the FSR, each showing the Brillouin linewidth.