Data centers are now the backbone of our interconnected world. As the demand for faster and more reliable data transmission grows, the importance of fiber testing in these data centers cannot be underestimated. This blog delves into the significance of fiber testing, the different methodologies employed, and the standards that guide these processes.
Why is Fiber Testing Crucial?
Fiber testing has become increasingly important especially with the emergence of higher-speed applications that have tighter loss budgets than previous applications. As consumers hierarchy of digital needs evolves, and increasingly demanding applications start to become indispensable, accurate, fast and reliable testing needs to be a critical component within the modern data center’s tool kit. For example, the shift towards using multi-fiber connectors, such as MPO-12, was initially to expedite installation and conserve space. However, with the emergence of applications like 400GBASE-DR4(which divides 400G over eight fibers), the importance of each fiber’s performance has been magnified. A single fiber with excess loss can bring the entire link down.
Standard industry practice dictates that it is required to test every fiber post-installation. This rigorous approach ensures that the installed cabling meets the required standards and can handle current and future data transmission loads. This practice has been further re-enforced with the evolution of fiber-intense architectures like spine-leaf and the rise of AI-optimised networks. The need for higher fiber count assemblies and consequently, more testing, has surged. This increasing demand, coupled with supply chain challenges, has made efficient fiber installation and testing times even more critical.
Testing Methods
There are two commonly referred to types of testing. Tier I testing is often the go-to for in-hall data center links, whereas Tier II testing Is often required for broader connections, like those between buildings. It’s all about ensuring that every splice, every connector, and every meter of fiber is up to standard.
Tier I Testing: This involves the use of an OLTS (Optical Line Test System). A basic OLTS consists of a light source and a power meter. The light source introduces light into the fiber being tested, and the power meter gauges the received power, thereby measuring the link loss. Tier I testers measure insertion loss, polarity and length.
Tier II Testing: Carried out with an OTDR (Optical Time Domain Reflectometer), this testing method delves deeper into link performance. It provides insights into individual events along the fiber’s length, such as connectors, splices, and bends. The OTDR can also detect faults, ensuring that every part of the connection is functioning optimally. In order to ensure our customers had access to robust tier 2 testing capability, we developed the FlexScan OTDR enabling operators to pinpoint fault locations, giving deep insight into individual fault events and the true performance of their fiber networks. In conjunction with the Multi-Fiber Switch, FlexScan can be used to rapidly test data center interconnect links terminated in MPO connectors.
Lastly, there are fiber identification tools, which help identify fibers and troubleshoot faults. The MT Tracer identifies potential faults and polarity types of MPO links, while the Visual Fault Identifier 4 (VFI4), provides a similar function for single fiber links. Both use visible red laser light to check continuity. If you see that light on the other end, you know you have a connection. It’s a quick way to verify polarity and identify fiber breaks. And for identifying live fiber in crowded overhead trays, tools like the OFI-BIPMe can be used without risk of interrupting traffic.
It’s not just about having the right tools; it’s about having tools that are tailored to the challenges of modern fiber optics.
While we’ve touched upon OLTS and OTDR, it’s essential to understand that these are just a part of the broader spectrum of testing methodologies. Each method has its unique advantages and is suited for specific scenarios.
Guidance from TIA/EIA, ISO and IEC Standards
These international standards play a pivotal role in ensuring that fiber testing is consistent, reliable, and meets global benchmarks. They offer comprehensive guidance on how testing should be executed, ensuring that data centers across the world adhere to a uniform quality standard.
A few examples of this are standards such as ISO/IEC 14763 and TIA 568.3 which provide loss limits for installed optical fiber cabling and include practices for inspection and testing of optical fiber .Applications standards such as the IEEE 802.3 series provide guidelines around maximum insertion loss and channel length based on the application supported.
AFL’s contribution to Efficient Testing
AFL has been at the forefront of enabling efficient fiber testing. All of AFL’s products are in line with industry standards set by esteemed bodies like ISO/IEC and TIA/EIA. This commitment to quality ensures that data centers equipped with AFL’s offerings are always at the pinnacle of performance and reliability.
Understanding and implementing effective fiber testing is crucial to the performance of modern data centers. Our commitment to providing quality, industry-standard products and solutions empowers data centers to meet the challenges of our interconnected world. We ensure your data center is equipped to handle the demands of today and prepared for the innovations of tomorrow.