Deep Trenches for Thermal Crosstalk Reduction in InP-Based Photonic Integrated Circuits

We numerically and experimentally investigate an on-chip solution to reduce the thermal crosstalk in indium phosphide-based photonic integrated circuits. We introduce deep trenches, fabricated through wet etch, between active and passive components. The current injected in active components and the geometry of the trenches are the parameters considered in our analysis. The trenches thermally isolate the passive components from the heat generated by active components. The thermal crosstalk is quantified by measuring the effects on the electro-optical response of an MZ modulator considered as a test structure. The heat sources are represented by semiconductor optical amplifiers placed at different distances with respect to the position of the MZ. Our experiments show how both the geometry and the position of the trenches, play a role in the reduction of the thermal crosstalk.