Today, the optical fiber is widely used in France, Europe and in the world. In France and Europe, we can mention the network that LDCOM comprises 11,000 km of fiber connecting 60 cities. By using WDM and SDH, it and can reach speeds of several hundreds of Gbit / s. Extended ends by MAN, the network now extends Spain, Italy and Switzerland. At the global level, the intercontinental routes are in perpetual changes to withstand the ever-changing traffic. Today, the recent work of the CNET (National Center for Studies in Telecommunications) on the show that soliton transmission can be push the limits inter-amplifiers. A soliton a very short light pulse which propagates without remarkable deformation of its shape or change its speed. This phenomenon has been noticed for the first time as a wave in a channel, but it exists in many fields, including light. Thus, one can use a very wide bandwidth with transmission speeds Agenda pétrabit per second or one million gigabit per second. The pulse modulation is based on the coding of the pulse corresponding to a logic with two or three levels. This technology has been used by MCI-WorldCom, which reached a speed 10 Gbit / s over 900 kilometers and CNET, in March 1999, which transferred data at a rate greater than one terabit per second 1000 km via a conventional optical fiber. The fiber seems to be the medium of the future in the relationship long distances.