Pushed by an urgent need on high-speed wireless connections, THz communications is now on fast track to be a 6G-enabler as a new wireless standard was released (IEEE 802.5.3d) in 2017. Most appealing technologies are i) photonics techniques, enabling highest data-rates and ii) solid-state technologies, enabling highest output powers. Within Europe, strong collaboration have been established between Univ of Lille and Univ Stuttgart; these two partners being world-class recognized institutes on these two afore-mentioned technologies. So far technologies exist on their own, and in SOLITONIC project we target to make a big boost ahead by co-integration of the core-chips, namely the Uni-travelling carrier photodiodes (French-side) and the solid-state amplifiers (German side). While simple association of French and German technologies already lead to state-of-the art demonstrations, co-integration will enable to target high performance integrated THz communication systems.