Objectives: The purpose of this project is to develop efficient and ultra-stable dual-frequency lasers at 1.55 µm. This laser will feed photomixers developed by ULIL and other partners to generate powerful and coherent THz radiation. Expected Results: Realization of a THz source based on a 100 mW compact and transportable Dual Frequency Laser (DFL) that will generate an optically-carried tunable THz signal by beating of the two optical IR modes, whose frequency spacing will be fixed at 280 GHz +/-3%. Also, because the two wavelengths share the same cavity in our DFL configuration, lower phase noise and smaller linewidth (< kHz) are expected. This research addresses Challenge I and V Planned secondment(s): To ULIL (Prof. Guillaume Ducournau), M24, ~2 months for generation of THz signals using photomixer developed at ULIL and telecom systems tests. To UCL (Prof. Cyril Renaud), M34, ~2 months for telecom systems tests