الفهرس 
CHAPTER ONE : INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
decade, due to the increasing needs to the applications it is used in. The high band width, and agility of use plus the security characteristics, attracts companies and researchers to develop the technologies related to it. The main applications used in (OWC) systems are wide, as an example of use is Last mile access is used to bridge the bandwidth gap (last mile bottleneck) that exists between the end-users and the fiber optic backbone Links ranging from 50 m up to a few km are readily available in the market with data rates covering 1 Mbps to 10 Gbps., back-up link are used to provide back-up against loss of data or communication breakdown in the event of damage or unavailability of the main optical fiber link. Link range could be up to 10 km with data rates up to 10 Gbps, High-definition television In view of the huge bandwidth requirement of high-definition cameras and television signals, (WOC) is increasingly being used in the broadcast industry to transport live signals from high-definition cameras in remote locations to a central office. Cellular communication backhaul Can be used to backhaul traffic between base stations and switching centers in the third/fourth-generation (3G/4G) networks, as well as transporting IS-95 CDMA signals from macro- and microcell sites to the base stations. Disaster recovery/temporary links This technology finds application where a temporary link is needed, be it for a conference or ad hoc connectivity in the event of a collapse of an existing communication network. Multicampus communication network FSO has found application in interconnecting campus networks and providing back-up links at fast-Ethernet or gigabit-Ethernet speeds Systems with data rates up to a few gigabits per second covering a link span of 1–2 km are already available in the market. Difficult terrains FSO is an attractive data bridge in instances such as across a river, a very busy street, rail tracks or where right of way is not available or too expensive to pursue. Military applications FSO can be used in military applications in secure – high band width communication between military bases and submarines, satellites and or missiles controls. The thesis is devided into chapters where each chapter talks about area of interest in the work done.
Chapter One had presented the introduction to this work and what area of interest of our study is covering the wireless optical communication systems.
Chapter Two was the literature review and related work for the study
Chapter Three was the mathematical model
Chapter Four has presented the results of study for wireless underwater communications, discussing the enhancing the input parameters such input power , operating wave length, distances between transmitters and receivers, optical antenna (lens) diameter, on the output parameters such as bit error rate (BER), signal to noise ratio (SWR) and output power , plotting the results and conclusion.
Also, was shown the careful balancing of single mode fiber attributes. Commercial single mode optical fibers are employed for this task, which that are namely Vascade® L1000 fiber, Vascade® LS+ fiber, Vascade® LEAF® fiber, Vascade® S1000 fiber, Vascade® EX 1000 fiber, and Vascade® EX 3000 fiber, High transmission capacity and long distance repeated submarine systems are achieved with attenuation and dispersion managed solutions as well as the effects of water depth, water pressure, and water temperature are taken into account in this study. The importance of minimizing dispersion slope within choosing suitable hybrid commercial submarine optical fibers to ensure good channel performance and wide system bandwidth. Vascade® R1000 fiber (mixed Vascade® L1000 fiber plus Vascade® S1000 fiber) that is namely dispersion managed fiber (DMF) offers a solution for high submarine system capacity. The figure of merit, cost planning budget, average repeater spacing, and possible transmission bit rate are the key solution for the tradeoff different commercial submarine optical fibers.
It was presented also, 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 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.
Also, discussed has presented optical wireless communication systems performance prediction based on different visibility levels for indoor, local, and wide area network applications s over wide range of the affecting parameters. Optical wireless links provide high bandwidth solution to the last mile access bottleneck. However, an appreciable availability of the link is always a concern. Wireless optical links are highly weather dependent and fog is the major attenuating factor reducing the link availability. Maximum permissible exposure, signal to noise ratio (SNR), atmospheric attenuation limitations, laser intensity fluctuations, and bit error rate (BER) are the major interesting design parameters in the current study.
Deep analytical study of free space and under water optical wireless communication systems performance parameters estimation over wide range of the affecting parameters. The effect of fog attenuation on optical wireless communication link is deeply investigated. Scattering coefficient, signal attenuation, receiver signal power, signal transmission, optical thickness or optical depth, link margin, data rate, signal to noise ratio (SNR), and bit error rate (BER) are the major interesting performance parameters in the current study for free space optics. On the other underwater optical wireless communication systems are also deeply investigated. 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.
Then the effect of erbium doped fiber amplifier (EDFA) as a pre and post amplifier in inter satellite wireless optical communication system and it is compared with semiconductor optical amplifier (SOA) as pre and post amplifiers in the same communication system design. The study is analyzed the effect of changing propagation distances between satellites spacing. Gain and bit error rate are investigated against the transmitter input power increase in both systems. The comparison between EDFA and SOA in inter satellite optical wireless communication system with different input parameters (input power and physical amplifier dimensions) is demonstrated. We are building information security management system using forward error correction (FEC), which is a digital signal processing technique used to enhance data reliability.
Lastly, building information security management system in organizations having optical wireless communication systems, the design was for optical communication system that can be implemented in military submarines or satellite base stations or satellite orbit to orbit systems. The management system is built to offer policies, processes and technologies proposed to secure the communication system. The polices were designed based on the proposed technologies, to ensure the compatibility between the systems components. And ensuring to cover the maximum threats known today. It was shown in this paper that the information security system was not negatively impact the performance of the system.
In chapter five was the final conclusion and future work.