The system includes an optical device having both optical components and one or more waveguides on a base. The system also includes a heat sink and a zone definer contacting the base and the heat sink. The zone definer is configured to conduct thermal energy from the optical device to the heat sink. The zone definer includes a thermal insulator having a lower thermal conductivity than both the heat sink and the base. The zone definer also includes a thermal via that extends through the thermal insulator. A via medium is positioned in the thermal via and has a higher thermal conductivity than the thermal insulator. The via medium is located under one of the optical components.