Our LED sources / loss test sets are Encircled Flux compliant. This applies to equipment produced since 2007.
This means they have a defined modal fill, to achieve consistent loss measurement between different items of test equipment.
Our LED source beam profile meets :
IEC 61280-4-1 Ed 3 Encircled Flux standards, at 850 nm into 50 u core fiber.
IEC 61300-1 Ed 3 "Equilibrium Modal Distribution" or "CPR or Coupled Power Ratio": Coupled Power Ratio Category 1 for 850 / 1300 nm, and 50 and 62.5u core fiber.
Simplifies loss testing, since special test leads are not required.
Avoids purchase, maintenance & management of expensive EF compliant test reference leads.
In field use, we found that with Kingfisher EF compliant LED sources, multimode test uncertainty is typically limited by randomly changing the test leads. If mandrels are also used, variability can be further improved. Expected test uncertainty is explored in further detail in Application Note.
The role of mandrel wraps
It is often wrongly assumed that a mandrel wrap can be used to create an EMD, CPR or EF modal condition. With modern multimode fiber, it does no such thing.
What a mandrel does do, is to strip off unstable edge modes, and so generally improve measurement consistency.
Kingfisher provides a pair of TIA-568-C.0 compliant mandrels with every LED source, for 50 u and 62.5 u core fiber. See brochure of mandrels for more detail.
