Chip-scale photonic interconnection networks have emerged as a promising technology solution that can address many of the scalability challenges facing the communication networks in next-generation high-performance multicore processors. Photonic interconnects can offer significantly higher bandwidth density, lower latencies, and better energy efficiency. Even though photonics exhibits these inherent advantages over electronics, the network designs that can successfully leverage these benefits cannot be straightforwardly extracted from typical electronic network methodologies and must consider the many unique physical-layer constraints of optical technologies. We conduct an architectural exploration of four chip-scale photonic interconnection networks in a novel simulation environment, measuring insertion loss, crosstalk, and power. We also explain and demonstrate the impact of these physical-layer metrics on the scalability, performance, and realizability of each design.