Nowadays, optical fiber are become a critical communication system which able to transforming data through cities, countries, regions and oceans with characteristic of high bandwidth and low attenuation. With addition, due to increasing the data rate, speed and long distance, optical fiber become most wide use to fulfill the transforming through long distance with greater bandwidth. In conducted project, we strive to concentrate on optical (transmission and networking) system with their characteristics and techniques. Additionally, we discuss the main components of optical fiber for instance types of fiber, dispersion and types of dispersion, non-linear effects, optical sources, DFB laser and VCSEL laser, optical photodiodes, optical amplifiers, WDM networks, opaque networks, transparent networks, agile optical networks, PON and types of PON, SDH/SONET and FTTH network scenarios.