What is Fiber Polarity
Fiber polarity fundamentally revolves around the alignment of transmit and receive channels in cabling systems. While it may seem straightforward, the management of polarity is essential for achieving peak performance and ensuring continuous service in data centers irrespective of their size.
Defining and maintaining best practices around fiber polarity during both installation phases and as a part of ongoing maintenance operations is essential for maintaining uptime.
The Consequences of Polarity Mismatches
Why is polarity such an important topic ? Consider a situation where fibers are not in the correct order . Such mismatches don’t just disrupt light transmission; they can compromise an entire network’s functionality. These issues are compounded if mismatches are only identified during live operation , as resolving them becomes a complex challenge. Ensuring correct polarity can be difficult for simple duplex systems; and has become an order of magnitude more so with the introduction of multi-fiber connectors such as the MPO-12 and MPO-24. And the fact that industry standards recognize multiple polarity “types” (A, B, C and U) adds to the complexity.
The repercussions of polarity mismatches in expansive data center environments are not just a matter of inconvenience. They can have a significant impact on meeting operational uptime SLA’s. Also consider the operational effort and cost involved in identifying and resolving issues, they can be significant. Worse case scenarios can be that mismatches can result in equipment damage as well as loss of customers due to not meeting uptime requirements.
Polarity Testing: A Comprehensive Approach
When it comes to checking polarity, those in the hyperscale domain must incorporate polarity testing throughout their operations. This includes the design phase, where polarity in diagrams and cable specifications is confirmed, when new equipment is received, during staging, throughout the installation process, and during routine maintenance.
Additionally, when issues arise, having polarity identifiers on hand is crucial for quick troubleshooting. AFL provides a number of tools to ensure engineers are able to test for and address challenges quickly as they arise to ensure impact is minimised.
Testing Methods
Visual Inspection: Before using any tools, a visual inspection should be done to check if the connectors and adapters are clean and free of any physical damage. Dirty or damaged connectors can cause issues even if the polarity is correct.
Use a Fiber Tracer or Visual Fault Locator (VFL): A VFL is a device that injects visible light into the fiber. By looking at where the light emerges you can determine if the fibers are connected in the correct order. If there’s a break or sharp bend in the fiber, the VFL will show light leakage at that point.
Use an Optical Power Meter and Light Source: Connect the light source to one end of the fiber link and the power meter to the other end. Transmit light through the fiber. If the polarity is correct and there are no breaks in the fiber, the power meter will detect the light at the expected power level.
Use a Polarity Test Kit: Some manufacturers offer polarity test kits specifically designed to check polarity, especially for MPO/MTP connectors which have multiple fibers in a single connector. These kits can be used to identify the polarity type (A, B or C) of trunk cables as well as to identify duplex break-outs.
Documented Procedures for Consistency
Beyond just testing, there’s a need for a systematic approach. Every data center should ensure they have a documented procedure for polarity verification. This documentation then ensures uniformity in practices, with every technician adhering to the same standards. By centralising the results of these tests, data centers can gain insights into their infrastructure’s polarity status and identify any recurring challenges.
Partnering for Success
AFL has a made significant investment in ensuring they are able to provide comprehensive solutions for test and inspection within the data center, Backed by extensive expertise and a rich history of supporting our valued customers, we pride ourselves on being more than just a solutions provider. We act as your partner ensuring that every aspect of your data center operates at peak efficiency.