Butt coupling process for InP based photonic integrated circuits

Photonic integrated circuits (PICs) require at least one integration between active sections and low loss passive sections. Among the different possible integration schemes such as evanescent coupling, selective area growth, MQW intermixing, butt coupling has the advantage of a completely separate optimisation of each section in terms of thickness, composition and electrical properties. This paper reports on a butt coupling technology, which can be considered as a building block for photonic integration. The main characteristics of the process-based on RIE and GSMBE-are described and the demonstration of low coupling losses is made.