It is commonly agreed that the next generation of wireless optical communication systems, usually referred to as fourth generation systems, will not be based on a single access technique but it will encompass a number of different complementary access technologies. Communication topics such as modulation, multiplexing, and detection are discussed in relation to optical wireless links. Negative channel effects such as dispersion and absorption are investigated with respect to their impact on the

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... channel and the associated bit error rates. The challenges posed by atmospheric disturbances are considered for free space links. As the backbone and the metropolitan area network technologies can increasingly provide unprecedented bandwidth capacities, the focus is being gradually shifted toward broadband access technologies capable of connecting the customer premises to the local exchange. Moreover, power link budgets are prepared for both fiber and wireless optical communication systems to illustrate the optical losses incurred during transmission. This paper proposed new technique for improvement the performance of voice and video signal quality over wireless optical links namely, modified Shannon technique.