Encircled Flux explained in 60 seconds

Encircled Flux is all about controlling how the light is launched into your cabling system under test. Different sources will yield different results, even if you are using the same Test Reference Cords and testing the same link. Let's take an example:

                                                           Measurement with OLTS 1

Measurement Encircled Flux OLTS 1

                                                           Measurement with OLTS 2

Measurement Encircled Flux OLTS 2
With OLTS 1 reporting 1.06 dB and OLTS 2 reporting 0.66 dB, there will be an argument as to which one is correct. That's why ANSI/TIA and ISO/IEC standards bodies collaborated on creating a standard to define the launch from a multimode source. This controlled launch is called “Encircled Flux”. Up until recently, the only Encircled Flux compliant solution was to use expensive bulky launch conditioners. That is no longer the case with the DTX-EFM2 fiber modules and EF-TRCs.

If you use the new DTX-EFM2 with EF-TRCs in accordance with the following knowledge base articles, there will be no disputing the outcome of you fiber optic loss test - assuming you are using the correct test limits for your installation of course.

ISO/IEC 11801:2011 (ISO/IEC 14763-3)