Performance comparison of parallel optical interconnects for enterprise servers

There is an emerging need in the computing industry for higher bandwidth, longer distance, and increased density interconnections within clusters of high performance enterprise-class computer systems. Many of these servers share a common set of high level requirements which lend themselves to the use of parallel optical interconnects to either supplement or replace existing copper data buses. In this paper, we describe the results of application testing performed on 12-fiber parallel optical cables and connectors, including a relative comparison between three different multimode cable assembly sources. Assembly loss and effects of both axial and off-axis pull forces are measured for cable samples mated to a laser transmitter array. Significant variations exist in the performance of the same type of cable assembly from different manufacturing sources, particularly concerning their susceptibility to pull forces; we also investigate the effects of fiber strain relief to improve performance of these links. While currently available 12-fiber array connectors are not equivalent in performance to standard duplex connectors, this work suggests areas for future improvement and data communication application requirements which should be considered when using parallel fiber optic arrays.