
 This study outlines the distributed feedback laser for signal power amplitude level improvement in the long spectral band of 1550 nm wavelength within supporting pumped wavelength of 1480 nm. The bias and modulation peak currents based distributed feedback laser are varied in order to test the signal power level, peak signal amplitude variations after the fiber-optic channel and light detectors. The signal power level, peak signal amplitude is measured against spectral wavelength and time bit period variations. The study emphasis the signal power level, peak signal amplitude are enhanced for the best selection values of both a bias current at 45 mA and modulation peak current at 0.5 mA.

Distributed Feedback Laser (DFB) for Signal Power Amplitude Level Improvement in Long Spectral Band


 System performance, which depends on the data transmission rates and propagation distances between two satellites in low Earth orbit (LEO) based on wavelength division multiplexing (WDM) techniques, is thoroughly studied. This study demonstrates the effect of WDM techniques on multi transceiver inter-satellite wireless optical communications. The system performance parameters with propagation distance at a multiple transceiver system are discussed using two previous models. The system performance parameters are investigated with 250 Gb/s transmission bit rates and 5000 km propagation distances for 16 transceiver systems. The maximum quality factor (Q factor), light peak signal per noise ratio, and signal peak per noise ratio are the primary important performance parameters in this study.

Wavelength division multiplexing techniques based on multi transceiver in low earth orbit intersatellite systems

\n This work clarified the conventional/phase shift dual Mach–Zehnder modulation measured technique for upgrading radio over fiber (ROF) systems. Four levels of pulse amplitude modulation and non-return to zero code scheme are employed in different previous studies for upgrading ROF systems. The possible transmission distance is extended to 150 km and a bit rate of 40 Gb/s for achieved acceptable max. Q factor of 13.7498 and minimum bit error rates of 1.82×10–43. The total optical received power is measured at fiber cable length for maximum distance. Also, in the same way, the signal power levels are measured after fiber optic cable and avalanche photo detector optical receiver. The proposed model has presented the enhancement percentage ratio of 13.654% over the previous models in signal quality enhancement.

Conventional/phase Shift Dual Drive Mach-Zehnder Modulation Measured Type Based Radio Over Fiber Systems

Abstract The purpose of this study was to clarify the silicon-germanium dioxide (SiGeO2) and Aluminum Indium Gallium Arsenide (AlInGaAs) based acoustic optic modulators for upgrading transmission performance characteristics. The transient time response of these modulators is analyzed and discussed in detail. The 3-dB modulation signal bandwidth, diffraction signal efficiency, signal rise time, and signal quality factor with minimum data error rates are also considered. The proposed models with silicon-germanium dioxide and Aluminum Indium Gallium Arsenide acoustic optic modulators were compared to the previous model with silicon acoustic optic modulators. The results confirmed the high-performance efficiency of the proposed models when compared to the previous model, in both the lowest transient time response and the highest acoustic optic modulators speed response.

/pdf/silicon-germanium-dioxide-and-aluminum-indium-gallium-3y46a6hobq.pdf

Silicon-Germanium Dioxide and Aluminum Indium Gallium Arsenide-Based Acoustic Optic Modulators

\n Different types of laser source modulation techniques have been used in various applications depending on the objective. As optical systems extract the laws and the best solutions from experiments and simulations, the present study uses simulation software with different modulation types so the output signals can be compared. The modulators used are Mach-Zehnder, which is an external modulator, and electro-absorption modulator and laser rate equation modulator, which are direct modulators. All these types have an optical link multimode (MM) fiber with a photodiode in the receiver end that can be modeled. The input and output signals are analyzed using different types of modulations.

Different modulation schemes for direct and external modulators based on various laser sources

In this paper, the influences of thermal and spectral variations on various structures of avalanche photodiodes (APDs) have been deeply investigated. The characteristics and performance of Silicon (Si), Gallium Arsenide (GaAs) and Indium Gallium Arsenide (InGaAs) avalanche photodiodes have been evaluated under effects of different temperature degrees. The impacts of different temperature levels on the band gap energy, detector responsivity, noise equivalent power (NEP), cut-off wavelength, dark current and the photocurrent are studied and analyzed in details. The signal to noise ratio (SNR) and Bit Error Rate (BER) of these APDs are also computed and measured under the influences of different temperature levels and spectral variations. The aim of this paper is to determine the most efficient avalanche photodiode achieving the best performance according to the maximum SNR and minimum BER at high temperature environments. The analysis of the proposed model is performed by MATLAB. It was found that the experimental measured results endorse the analytical computed results. Further, it was observed that the APD (InGaAs) provides performance better than other APD structures in terms of larger SNR and less BER at higher temperature levels. Also, the temperature has a slight effect on the performance of APD (GaAs). So, it is seemed to be stable more than other APD structures and recommended to be used in warm environments and for high temperature applications.

Temperature effects on characteristics and performance of near-infrared wide bandwidth for different avalanche photodiodes structures

The recent progress in optical computing outlines the fact that electronic computing has almost failed to cope with the international optical computation and communication traffic demand. Thanks to the non-linear material (NLM) which pave the way to new designs of new optical devices. A proposal for developing the most basic element in the optical computer such as optical switch, optical gates like OR gate, AND gate, XOR gate, flip-flops…. etc. has been introduced in recent research papers, also a proposal of the optical logic and arithmetic processor (OLAP) and the all-optical a-stable multi-vibrator has been introduced. Here some proposal developments are presented in this track, three components which they are most important in any new optical project those are optical switch, optical oscillator, and optical trap, the optical oscillator was introduced using an electro-optical modulator and, in this study, the oscillator design has no electro-optical elements, also the optical trap here works as an optical memory of binary data.

The switching of optoelectronics to full optical computing operations based on nonlinear metamaterials


 This study has presented spatial continuous wave laser and spatiotemporal vertical cavity surface emitting laser (VCSEL) for high speed long haul optical wireless communication channels. Possible data rates range from 40 Gb/s to 250 Gb/s over propagation distance ranges from 500 km to 2500 km. The optical wireless communication (OWC) system performance is tested through the measurement of maximum Q-factor, minimum bit error rate (BER) and signal to noise ratio (SNR). It is observed that spatiotemporal VCSEL has presented better performance than CW laser in the OWC system, especially for long haul transmission applications. It is observed that SNR improvement ratio ranges from 8.15 % to 19 % by using spatiotemporal VCSEL than CW laser for bit rate of 40 Gb/s over propagation distance ranges from 500 km to 2500 km. Max. Q-factor improvement ratio ranges from 4.62 % to 13.71 % by using spatiotemporal VCSEL than CW laser for data rate of 40 Gb/s over propagation distance ranges from 500 km to 2500 km. So it is clear that spatiotemporal VCSEL is more suitable for long haul OWC applications than other optical sources.

Spatial Continuous Wave Laser and Spatiotemporal VCSEL for High-Speed Long Haul Optical Wireless Communication Channels

\n This work clarified the performance enhancement of transceiver system based (IS-OWC) link by using both vertical cavity surface emitting laser diode (VCSEL) and continuous wave (CW) laser sources. The proposed model has been investigated and discussed. The inter satellite link has been modelled by using optisystem simulator at 10 Gb/s and 40 Gb/s for long distance up to 5000 km by using return to zero (RZ) and non return to zero (NRZ) schemes. The performance of IS-OWC system has been investigated by estimating the evaluation parameters such as Q-factor and bit error rate (BER). The results revealed that the NRZ is superior to RZ due to its reduced bandwidth. The BER obtained at 5000 km distance for NRZ scheme is 10−12 and 10−10 when using VCSEL and CW laser source respectively. The Q-factor records higher values at different distances when using VCSEL.

Performance enhancement of transceiver system based inter satellite optical wireless channel (IS-OWC) for ultra long distances

\n The most powerful computer is in a very big need for a reliable random access memory (RAM) which can buffer digital data in. All optical RAM design is introduced in three phases. Those are the loading process phase which describes how data will be entering the closed trap from the line bus. The regeneration process phase which describes how data trapped are regenerated to not to lose its power or get a distortion. As well as the recalling process which describes how trapped data be handled to the line bus is also introduced.

Abd El-Naser A. Mohammed

Papers

Temperature effects on characteristics and performance of near-infrared wide bandwidth for different avalanche photodiodes structures

The switching of optoelectronics to full optical computing operations based on nonlinear metamaterials

Spatial Continuous Wave Laser and Spatiotemporal VCSEL for High-Speed Long Haul Optical Wireless Communication Channels

Performance enhancement of transceiver system based inter satellite optical wireless channel (IS-OWC) for ultra long distances

Influence of Loading, Regeneration and Recalling Elements Processes on the System Behavior of All Optical Data Bus Line System Random Access Memory