AWG-based architecture for optical interconnection in asynchronous systems

We present a novel architecture for strictly non-blocking multistage photonic switches implemented using tunable wavelength converters and arrayed waveguide gratings. Clos networks, studied mostly in electronic domain, are required when the physical switching needs exceed the capacity of the largest feasible single crossbar switch. Unfortunately, straightforward extensions of these networks to the photonic domain show that the switch size has to be severely limited by the coherent crosstalk in each of the AWGs. We describe how recursive Clos networks free of coherent crosstalk can be built taking into account the current physical limitations of arrayed waveguide gratings.