تکامل اجزای کابل کشی فیبر نوری در سازمان اروپایی پژوهش‌های هسته‌ای (CERN): عملکرد و تجزیه و تحلیل روند تکنولوژی Evolution of optical fibre cabling components at CERN: Performance and technology trends analysis

1. Introduction The European Organization for Nuclear Research (CERN), is home to a large accelerator complex, thereunder the Large Hadron Collider (LHC). Every year a substantial volume of optical fibre cabling components (i.e. fibre cables, connectors, etc.) are supplied through an industrial support contract and installed under the responsibility of the Fibre Optics and Cabling Section (FCS) in Engineering Department, Electrical Engineering Group [1]. CERN optical fibre installations cover a wide range of connectivity applications. Apart from the internet connection network, several other services employ extensive fibre installations. For example, the accelerator Timing and Synchronization system implements a modified GPON standard which requires a substantial fibre connectivity [2]. Another example is the Electrical Network Control system, which constantly measures vital control parameters of the power distribution systems (equipment alarms and temperature) through a specific fibre infrastructure [3]. Security, Surveillance and Access Control systems have recently requested a considerable volume of fibre connectivity due to a major hardware upgrade. Above all, with new Data Centers (DC) under design and construction, the DC interconnect is expected to require a significant fibre installation [4,5]. Transmitting such a high data volume through the fibre infrastructure necessitates regular provisioning and upgrade plans [6]. One insightful approach for such planning is to study the trend of past deployed technology. In fact, analyzing the procurement data in recent years can reveal evolution of various connectivity solutions. In particular, such analysis shows the direction of dominant solutions which in turn can be used for directed market surveys and resource allocation in the forthcoming installations. On the other hand, once the fibre cabling components are installed, their reliability becomes vital for the accelerator harsh environment through their role in conveying critical data. Indeed any major defect in optical components can impose an unintended downtime, leading to a considerable maintenance cost [7]. Therefore, considering the complex procurement process, the reliability assurance of these components necessitates special provisioning which involves systematic performance monitoring of selected samples. The first part of this paper studies the evolution of various components installed by FCS during a five-year interval. These components cover the major passive elements of structured fibre cabling including conventional and microduct fibre cables, pre-terminated fibre cables and optical connectors. The analysis results will be used to predict the direction of optical fibre installation in various sectors and provide valuable feedback for future procurement and planning activities. The second part of the paper is dedicated to statistical performance analysis of the procured components in the same time interval with the focus on connector Insertion Loss (IL) and Return Loss (RL). The analysis results can be used to monitor the essential quality criteria and to provide an assessment benchmark among different connector types.