High-performance packet switches are costly, bulky and power-hungry. Their scalability is constrained by the limits of electronic technology at high binary rates. In this paper we study the benefits of introducing optical technology in the switch fabric architecture, to cope with this bottleneck. In particular, we study the replacement of the switch fabric boards in the Cisco 12816 architecture, by two optical architectures based on arrayed waveguide gratings (AWGs) and tunable wavelength converters (TWCs). The results illustrate the potential benefits in terms of power consumption and system scalability that these optical architectures could bring to commercial routers.