The Optical Time Domain Reflectometer (OTDR), both single and multimode, is one of the most versatile and widely used pieces of fibre optic test equipment. The instrument is used in both the laboratory and in the field to probe the attenuation along a length of fibre and to locate breaks in fibres. The usefulness of an OTDR depends on the accuracy of its attenuation and distance scales.

NPL has developed calibraton artefacts for the calibration of OTDRs. Further information can be found by downloading this data sheet ( PDF, 99 kB) and from these links:

• Attenuation or loss scale calibration
• Length and Distance scale calibration
• Return Loss

Also available is the NPL Good Practice Guide "Calibration and use of Optical Time Domain Reflectometers (OTDR)".