Abstract

The exponential growing of the requested bandwidth capacity for high performance computing systems requires the development of novel backplane solutions within the rack as well as for the rack-to-rack fabric interconnections [1]. The solutions currently used are based on copper interconnections via backplane, driven by a suitable transceivers subsystem. The evolution of the transmitting and receiving interfaces, of the connectors, and of the printed board (PB) technology has allowed to increase the single interface bandwidth, limiting the power consumption and increasing the integration. While the consumption measured in W per Gb/s has had an exponential decrease, the consumption of the interface including serializer/deserializer, clock data recovery, pre-emphasis and equalization is growing. Furthermore, the complexity and density increasing is supported by evolving silicon technology able to manage more W/mm². The realization of the transmission lines in PB even if based on the most sophisticated materials available on the market, shows very significant losses at very high working frequency. Also connectors, even if now very optimized, contribute to increase loss and crosstalk. We believe that the electrical backplane is close to reach its limitation. Hence, alternative solutions have to be explored. Due to the fact that optical technologies [2-4] are able to provide higher capacity over longer distances than electrical transmission systems, a natural answer to the limitations shown by the Cu-based interconnections is to exploit fiber optical backplane [5].

© 2013 IEEE