CABLExpress® Cable Talk™ #25 - Facts vs. Hype on fiber optic assemblies
Many a cable professional is submitted to a barrage of stats and specs and test results on how a manufacturer’s fiber optic assemblies are the best. Well, we can’t all be the best, can we?
Well, today we’re gonna get down to the nitty-gritty on fiber optic test results and separate the hype from the facts. To supplement your understanding on what we’re about to cover be sure to cover Episode #11 where we talk about fiber optic link loss, because once you understand the basics this is easy.
Insertion loss is the most critical measurement for data center fiber optic cabling. Insertion loss is the amount of light lost measured in dB (or decibels) from the transmitting signal to the receiver. If too much light is lost in that channel you’ll have downtime. And nobody wants that.
On a fiber jumper, results will be given for each end: A and B. Each end has a duplex connection containing two fibers, one and two. Sometimes the results will be noted as an assembly loss and that’s when you have the loss of the entire assembly, it will be added up. Otherwise it would be insertion loss and that’s the loss measured on just one connector.
The numbers you see are measured in dB. Be sure to see Episode #24 where we talk about loss budget. That will really help you get a great understanding of the entire concept. When comparing manufacturing specs, be sure to note whether it’s a typical loss or if it’s a maximum value. Typical loss is no way to balance a budget because it could be much higher than that. But if you know what the maximum loss value is that’s the best way to budget because you’re sure to be under that.