4. Conclusion
Five year evolution of CERN optical fibre cabling components was studied. The analysis of procured pre-terminated cables shows the increasing share of multi-fibre connectors and multi-fibre cable solutions This pattern is aligned with data centre segment which relays on increasing data rates by providing parallel optical paths. The analysis also shows blowing microduct is the major technique for installing nonterminated fibre cables. Moreover, it is clearly observed that the majority of conventional and microduct fibre cables are of single-mode type which is essential for interconnecting typical distances at CERN. The analysis was extended to the optical performance of various connector types by obtaining the insertion loss and return loss probability distributions. The results show E2000 and LC connectors exhibit an insertion loss around 0.1 dB. Accordingly, they are set as standard CERN connectors in distribution points. In particular, E2000 takes advantage of an extremely low return loss thanks to the angled ferrule design. Multi-fibre connectors, despite exhibiting high return loss variance, have a low average insertion loss of 0.07 dB which is determining for data centers. Finally, the newly introduced expanded beam multifibre connectors showed a very stable return loss and acceptable 0.54 dB average insertion loss when manufactured with anti-reflection coating. Expanded beam connectors have not been widely used at CERN but they seem promising for future ultra-high density connectors.
