Photonic Networks-On-Chip have emerged as a viable solution for interconnecting multicore computer architectures in a power-efficient manner. Current architectures focus on large messages, however, which are not compatible with the coherence traffic found on chip multiprocessor networks. In this paper, we introduce a reconfigurable optical interconnect in which the topology is adapted automatically to the evolving traffic situation. This allows a large fraction of the (short) coherence messages to use the optical links, making our technique a better match for CMP networks when compared to existing solutions. We also evaluate the performance and power efficiency of our architecture using an assumed physical implementation based on ultra-low power optical switching devices and under realistic traffic load conditions.