This project deals with the design and implementation of a laser system and a dedicated focusing module for the ignition of a two-phase flow in the aerobic aeronautic chamber. The ignition, and more particularly the re-ignition of aeronautic engines in flight conditions, is a crucial point for the aeronautic and it directly impacts the volume of the combustion chamber. Aeronautic companies developing engines are actively seeking for systems making possible to ignite at high frequency (~ 100 Hz) combustion chambers requiring active re-ignition, including chambers with rotating detonation or constant combustion volume. Making available a reliable and an efficient ignition device working at high frequency is therefore of great importance for aeronautic engines manufacturers. Hence, the main idea of this project is to develop a system consisting in a laser and focusing module making possible the ignition of the two-phase kerosene / air mixture of an aeronautical injector under altitude flying conditions (-40 ° C, 0.5 bar). The development of this system is made possible thanks to the know-how and innovative results acquired during the ASTRID ECLAIR project. The optical and mechanics parts of the laser system will be designed and build by Fibercryst. A compact electronic device making possible to pump and synchronize this laser system will be designed and build by the LOMA in strong interaction with Fibercryst which will provide the key electronic parameters. This electronic device derived from a system previously designed by the LOMA will be operated under 24 V. The laser system will deliver at 100 Hz repetition rate, laser pulses of 1.5 nanoseconds with quasi-Gaussian profile (M2 <1.5) centered at 1064 nm which energy will be greater than or equal to 40 mJ. These laser pulses will be focused in the combustion chamber by a dedicated focusing module that will be designed and built by LOMA. At the point of focus, these pulses will create plasma that will generate a combustion kernel and ignite the combustion. In parallel, we will characterize the kerosene spray of SAFRAN's Ardiden trisector under different operating conditions. A better knowledge of the parameters of the kerosene spray as a function of the temperature and the pressure will improve notably the predictive character of the computation codes of the dynamics of the fluids and will make it possible to optimize the conditions of ignition of the Ardiden motors developed by SAFRAN HE. Using our laser device and focusing module, we will carry out ignition tests on the ARDIDEN trisector installed on the MERCATO bench of ONERA. This bench is the French reference for the study of the ignition of aeronautic combustion chambers under real flight conditions. The performances of our laser igniter will be determined using optical diagnostics installed on MERCATTO and compared to that of conventional spark plugs that will serve as a reference. Finally, we will also test the ability of our system to ignite a complete annular chamber installed on the bench 5 of Safran HE at Bordes. These latter experiments will make it possible to test the ability of our system to ignite an aeronautic engine under different flight operating conditions.