Optical packet switches enhanced with electronic buffering and fixed wavelength conversion

Optical networks with Wavelength Division Multiplexing (WDM), especially Optical Packet Switching (OPS) networks, have attracted much attention in recent years. However, to make OPS practical, it is crucial to reduce the packet loss ratio at the switching nodes. In this paper, we study a new type of optical switching scheme for OPS which combines optical switching with electronic buffering. In the new scheme, the arrived packets that do not cause contentions are switched to the output fibers directly; other packets are switched to shared receivers and converted to electronic signals and will be stored in the buffer until being sent out by shared transmitters. Since full range wavelength converters are difficult to implement with available technology, we focus on the more practical fixed wavelength conversion, with which one wavelength can be converted to another fixed wavelength. We will show with both analytical models and simulations that the packet loss ratio can be greatly reduced with few additional receivers and transmitters. Thus, we believe that the proposed hybrid switching scheme can greatly improve the practicability of OPS networks.