A novel routing and buffering architecture in an all-optical switching node

Optical packet switching is seen as a solution to the enormous demands being put on electronic switching nodes. Usually the routing and contention resolution operations are undertaken as two sequential stages; this has the effect of increasing the node insertion loss due to the addition of optical components, and adding complexity to the associated control electronics. The proposed architecture simplifies the two functions by utilising the free-spectral range (FSR) of an arrayed-waveguide grating (AWG) to simultaneously route a packet to the desired output port of the node and optically buffering it if a contention condition arises. In addition, the inclusion of add/drop functionality does not require an increase in the size of the AWG, which is an important factor when considering the detrimental effects of optical crosstalk within the photonic switching matrix.