Optimization of a WDM optical packet switch with wavelength converters

This paper investigates a wavelength-division-multiplexed optical packet switch with wavelength converters which can shift optical packets to any wavelength of their destined outbound links. Wavelength conversion can reduce packet dropping probability due to wavelength contentions. However, not all the packets need conversion, and hence conversion should be optimized to reduce the number of converters and improve the quality of signals by reducing unnecessary conversion. We derive the maximum number of conversions in a packet switch with l inbound/outbound links and w wavelengths per link and develop a switch control algorithm to minimize the number of wavelength conversions while maintaining the same minimum number of dropped packets. Simulation results show that the packet dropping probability decreases significantly with wavelength conversion and that fewer converters than the maximum number of conversions are needed.