This project is part of the large megajoule laser-type laser plants at CEA in France, whose aim is to ensure a high level of knowledge in the field of nuclear energy. Indeed, these gigantic lasers (100x300 m²) make it possible to generate a miniature and controlled nuclear reaction by means of a laser beam focused on a target of a few millimetres. These fundamental studies could lead to the development of clean and reliable future energy sources based on laser-induced nuclear fission. They could meet one of the major challenges we will have to face by the end of the century, namely to produce 4 times as much energy as it is at present. A technological and scientific break is necessary because this unthinkable objective with the current means of energy production. Before such systems can be developed, it is essential to secure and reduce the size of such facilities. In this project we propose to replace part of the massive lasers used in this facility, bulky and complex to maintain, with much more compact and easy-to-maintenance fibre lasers. More concretely, we propose to develop fiber optic amplifiers to amplify very short pulses temporally with unprecedented energy levels for this category of systems. They will be advantageously able to replace massive systems