National Physical Laboratory

OTDR Distance Scale Artefact

Distance Scale Artefact
Distance scale artefact

The artefact is based on a recirculating optical delay line, which will generate a number of calibration features along the distance scale of an OTDR. A typical OTDR trace can be seen below. A 2 km lead-in fibre together with a 12 km loop will provide features every 6 km out to about 40 km. Other combinations of lead-in and loop fibre lengths can be supplied on request. A multimode version of the distance scale artefact is also available.


Fibre Type Lead-in Fibre Length Calibration Uncertainty Recirculating Loop Fibre Length Calibration Uncertainty Measurement Wavelength
Single-mode ~2 200 m ± 0.1 m ~13 000 m ± 0.3 m 1310 and 1550 nm
Multimode ~1 000 m ± 0.3 m ~4 400 m ± 0.5 m 850 and 1300 nm

The device is packaged into one box, fitted with an FC/PC terminated patch lead for direct connection to the OTDR.

OTDR TraceTypical OTDR trace from Distance Scale Calibration Artefact 

A copy of a typical Calibration Certificate is available to download.


Customer Service tel: +44 20 8943 8637

Last Updated: 25 Mar 2010
Created: 23 Jul 2007


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