1 Scope
This technical report describes two methods for the measurement of the sensitivity
of single-mode optical fibres to high-power damage at bends:
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• test method 1 – Failure time characterisation as a function of the launch power and bend conditions (bend angle and bend diameter);
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• test method 2 – Equilibrium temperature measurement.
Results from the two methods can only be compared qualitatively.
The results in this report are predominantly on un-cabled and un-buffered fibres.
Cabled and buffered fibres are expected to respond differently, because the outer
layers can affect the ageing process. Note also that test method 2 testing cannot
be applied to buffered or cabled fibres.
These methods do not constitute a routine test to be used in the evaluation of optical
fibre.
The parameters derived from the two methods are not intended to be specified within
a detailed fibre specification.
The catastrophic failure modes arising and which are described in this document in
general occur at bending radii much smaller than specified in the single-mode fibre
specification IEC 60793‑2‑50 or than would be recommended based on mechanical reliability considerations alone.
This report includes several annexes, including a discussion on the rationale for
the approaches adopted, metrics for assessment, guidance, examples and some conclusions
from initial studies.