Microfluidic Cooling of Photonic Integrated Circuits (PICS)

It is widely believed that the current telecommunications network is required to grow by more than 10X in the coming years to satisfy the demands placed on it by an increasing number of connected devices, in particular content streaming to mobile devices. To enable this growth, significant enhancement in the bandwidth capacity of Photonics Integrated Circuits (PICs) is necessary. Contemporary high density PICs represent a significant thermal management challenge particularly for active optical components such as laser arrays. Each individual laser operates under tight, sub ambient temperature limits (0.1C) and extremely high heat fluxes (over 1kW / cm2). In addition, adjacent lasers require different operating temperatures, meaning local tuning of the thermal management solution. Thermoelectric modules (TEMs) and resistive heaters are currently used to achieve thermal control, however this method is limited by the packages environment and poor efficiency. In order to enable the next generations of PICs, Bell Labs Thermal Management Research Group in collaboration with the CTVR Telecommunications Research Centre has identified the need to move to a liquid based micro Fluidics cooling solution that can tackle the high heat fluxes while providing thermal control of individual optical devices within the photonics package. In this paper, the ongoing activities surrounding the integration of microfluidics within photonics packages are presented. This includes novel microscale pump and heat exchanger designs that are being developed to address key areas that currently limit the practical implementation of microfluidics cooling.