Fiber Testing in Data Centers – Bringing Theory and Practice Workshop#

Svetoslav Nikolov, Jürgen Rummelsberger (EXFO), Kimberley Rotolo, Markus Eilers

• Why: As speeds increase past 400G, fiber plant testing and transceiver validation become critical. The workshop also introduces measurement techniques for hollow-core fiber (HCF) — an emerging technology for ultra-low-latency DCI that the PM should be tracking as it matures.
• What: A theoretical and hands-on workshop covering: essential fiber testing principles (insertion loss, return loss), verification of link stability via Pre-FEC BER monitoring, host-to-module interoperability testing via CMIS, transceiver validation (proactive before install, reactive during troubleshooting), and high-speed breakout cable testing. Also introduces HCF measurement techniques — HCF is emerging for ultra-low latency and high-capacity applications, and the testing challenges differ from standard SMF.
• How: Testing methodologies use EXFO platforms (FTBx-88480 series and above, 800G HW-ready) for 400G/800G Ethernet, DCO BERT for 400ZR/OpenZR+ coherent modules, and CMIS testers for host-to-module interoperability. Transceiver validation distinguishes between proactive (pre-install) and reactive (troubleshooting) scenarios.
• Where applicable: DC operators deploying 400G+ where fiber plant quality directly impacts link margin and where transceiver validation catches defects before installation. HCF content is forward-looking for latency-critical DCI. EXFO vendor workshop but the testing principles are standards-based (IEEE, MSA, CMIS).