Thermal Aspects of Silicon Photonic Interposer Packages

Future high-performance applications require in-package optical modules to enable the high bandwidth requirements. This is enabled by the co-integration of a silicon photonics module with a host IC in a single package. Since the silicon photonic elements are very sensitive to temperature changes, the optical performance can be affected by the thermal coupling effects in these co-integrated packages.In this paper, a thermal modeling study is presented for the test case of a BGA package that contains a 300W host IC and an Si photonics optical I/O module with 32 channels. The thermal model, calibrated with global package level measurements, are well as with local device measurements, shows a large level of thermal coupling from the host IC to the optical module. Although the thermal coupling between individual photonic elements is shown to be in the order of 1%, the combined thermal coupling for the 32 channels reaches 28%, indicating the clear need for a detailed thermal analysis.