Abstract
We present results on optical crosstalk in the photonic integration platform developed at Fraunhofer HHI. Two fundamental mechanisms are investigated: stray light generation at butt-joints and coupling between two passive waveguides. The latter can happen in two regimes: evanescently or radiatively, depending on the gap between the waveguides. Measurements show the amount of crosstalk that is to be expected on ASPICs. Moreover, means to reduce crosstalk levels that are compatible with the existing technology are demonstrated.