1 Scope
This part of IEC 60793
establishes uniform requirements for measuring the cut-off wavelength of single-mode
optical fibre, thereby assisting in the inspection of fibres and cables for commercial
purposes.
This document gives methods for measuring the cut-off wavelength for uncabled or cabled
single mode telecom fibre. These procedures apply to all category B and C fibre types.
There are three methods of deployment for measuring the cut-off wavelength:
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• method A: cable cut-off using uncabled fibre 22 m long sample, λcc;
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• method B: cable cut-off using cabled fibre 22 m long sample, λcc;
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• method C: fibre cut-off using uncabled fibre 2 m long sample, λc.
All methods require a reference measurement. There are two reference-scan techniques,
either or both of which can be used with all methods:
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• bend-reference technique;
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• multimode-reference technique using category A1(OM1-OM5) multimode fibre.