Multimode test standard compliance
What it does
Our LED sources / loss test sets provide a defined symmetrical power density profile across a typical multimode fiber core, without which multimode loss measurements are "too variable".
This applies to all our equipment produced since 2007. A very minor correction was made a few years ago to comply with the latest standards.
Our beam profile meets old & new established practice of "Equilibrium Modal Distribution" or "CPR or Coupled Power Ratio" IEC 61300-1: Ed 2 2004, and also current Encircled Flux standards IEC 61280-4-1 Ed 2 (2009).
The current standards are IEC international standard for Encircled Flux Compliance at 850 nm into 50 u core fiber, and Coupled Power Ratio Category 1 for 850 / 1300 nm, and 50 and 62.5u core fiber.
The technical objective of EF compliance is to keep loss test variability due to source geometry variation, within 10% of the measured loss value.
Improves test consistency
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 21.
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.