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.
Extended temperature performance of 120 Gbps midboard optical engine
Industrial and military requirements for optics dictate the ability to operate reliably over a myriad of extreme environmental conditions such as extended temperature, increased shock and vibration, high particulate environments, etc. While it is paramount that the transceiver be able to maintain performance over these extreme conditions, considerations for the optical interconnects in the signal path are often overlooked. In general, optical performance tends to degrade as the operating temperature drifts from nominal conditions. Likewise, optical connector performance degrades at higher shock and vibration levels. As a result, optical products are generally limited to operating at case temperatures between 0 °C – 70 °C and struggle at high shock and vibration levels. In this paper we demonstrate the performance of the Samtec 12 channel FireFlyTM at 10 Gbps, -40 °C and 85 °C case temperature coupled with the expanded beam MXCTM connector from US Conec. Optical eye diagrams and receiver sensitivity for a link that includes 100 m of OM3 fiber, reliability results for transmitters operating at extended temperature, and shock and vibration data are presented.
Parameters for low energy operation of CESR
We present a detailed design for operation of the Cornell Electron Storage Ring, CESR, in the energy range covering the /spl psi/ resonances and the Charm and Tau thresholds, as well as reaching to the upper Y resonances near 11 GeV. The addition of 18 m of super-ferric wiggler magnets will partially restore low energy beam emittance and damping times. Installation of superconducting quadrupoles in the interaction region and the addition of high performance superconducting RF cavities will enhance performance at all energies. Studies of optics, beam dynamics, wiggler and vacuum system performance, beam stability, and beam-beam effects confirm operation with a luminosity of 3/spl times/ 10/sup 32/ CM/sup -2/ sec/sup -1/ at 1.88 GeV.