Bandwidths of micro twisted-pair cables and fusion spliced SIMM-GRIN fiber and radiation hardness of PIN/VCSEL arrays

We study the feasibility of fabricating an optical link for the SLHC ATLAS silicon tracker based on the current pixel optical link architecture. The electrical signals between the current pixel modules and the optical modules are transmitted via micro-twisted cables. The optical signals between the optical modules and the data acquisition system are transmitted via rad-hard SIMM fibers spliced to rad-tolerant GRIN fibers. The link has several nice features. We have measured the bandwidths of the transmission lines and the results indicate that the micro twisted-pair cables can transmit signals up to ∼1 Gb/s and the fusion spliced fiber ribbon can transmit signals up to ∼2 Gb/s. We have irradiated PIN and VCSEL arrays with 24 GeV protons and find at least one candidate PIN and one VCSEL array that can survive to the SLHC dosage.