Sparse WDM optical interconnects under wavelength-based model

Optical communication, in particular, wavelength division multiplexing (WDM) technique, has become a promising networking choice to meet ever-increasing demands on bandwidth from emerging bandwidth-intensive computing/communication applications. As optics become a major networking media in all communications needs, optical interconnects will inevitably play an important role in interconnecting processors in parallel and distributed computing systems. In this paper, we consider cost-effective designs of WDM optical interconnects for current and future generation parallel and distributed computing and communication systems. We first classify WDM optical interconnects into two different connection models based on their target applications: the wavelength-based model and the fiber-link-based model. We then focus on the wavelength-based model and present a minimum cost design for WDM optical interconnects by using sparse crossbar switches instead of full crossbar switches in combination with wavelength converters. We also show another design which can trade-off the switch cost with wavelength converter cost in this type of WDM optical interconnect.