Radiation-Hard Optical Link for SLHC

TL;DR

This paper explores the design and testing of a radiation-hard optical data transmission link for the SLHC ATLAS silicon tracker, demonstrating its feasibility with irradiated components and novel packaging solutions.

Contribution

It introduces a radiation-tolerant optical link architecture with tested bandwidths and irradiated components, including a new opto-pack design for SLHC conditions.

Findings

Micro twisted-pair cables achieve ~1 Gb/s bandwidth.

Fusion spliced fibres achieve ~2 Gb/s bandwidth.

PIN and VCSEL arrays operate up to SLHC radiation doses.

Abstract

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 radiation-hard/low-bandwidth SIMM fibres fusion spliced to radiation-tolerant/medium-bandwidth GRIN fibres. The link has several nice features. We have measured the bandwidths of the micro twisted-pair cables to be ~ 1 Gb/s and the fusion spliced fibre ribbon to be ~ 2 Gb/s. We have irradiated PIN and VCSEL arrays with 24 GeV protons and find the arrays can operate up to the SLHC dosage. We have also demonstrated the feasibility of fabricating a novel opto-pack for housing VCSEL and PIN arrays with BeO as the substrate.