Mode Field Diameter (MFD) Reference Fibre
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The mode field diameter, MFD, is a measure of the width of the fundamental guided mode and is used to predict joint and bend losses within optical fibre links. NPL can supply reference fibres, which include measurements for Mode Field Diameter and Effective Area that can provide network system designers and engineers with a traceable artefact for their own test equipment.
The artefact consists of the cleaved end of an approximate 12 m length of matched clad or dispersion shifted single-mode optical fibre. The fibre can be supplied bare or mounted in a retractable holder. When mounted in the holder, the cleaved end is held in a zirconia ferrule that is itself fitted into a brass barrel. The brass barrel is fitted inside an aluminium holder such that the cleaved end can be retracted inside the housing or exposed through a small hole for measurement.
The certified MFD corresponds to the MFD of the cleaved fibre end and is the measurement of the width of the fundamental guided mode within the fibre. The fibre is used for calibrating instruments that measure the mode field diameter (MFD) of optical fibres.
A copy of a typical Calibration Certificate for a fibre mounted in a holder is available to download.
Specification
| Mode field diameter | MFD Value in the range (µm) | Typical Uncertainty (µm) | Aeff Value in the range (µm2) | Typical Uncertainty (µm2) |
| G.652 fibre @ 1310 nm | G.652 fibre @ 1310 nm | ± 0.07 | 60 – 70 | ± 1.4 |
| G.652 fibre @ 1550 nm | 9.9 – 10.9 | ± 0.07 | 75 – 85 | ± 1.7 |
| G.653 fibre @ 1310 nm | 6.6 - 6.9 | ± 0.06 | 30 – 40 | ± 0.8 |
| G.653 fibre @ 1550 nm | 8.5 - 8.8 | ± 0.06 | 50 – 60 | ± 1.2 |
Calibration at other wavelengths is available on request.