Tight new fibre-optic testing limits needed for higher bandwidth apps

With the ratification of 40 and 100 Gbps ethernet fibre standards, optical requirements are tighter than ever before. Yet testing methods have not caught up.

Also consider with the introduction of 10Gbps over ethernet, the maximum power loss budget for multimode fibre links has dropped significantly, and it is clear changes in testing standards are essential and urgent.

While an accuracy of 0.5 to 1dB might have been tolerable in the past, it is not acceptable with the 10Gbps or higher standards, especially as the demand for 1.5dB maximum power loss with OM4 fibers for 40 and 100Gbps applications requires precise test equipment and test procedures.

ISO/IEC 14763-3 was launched in 2006, with amendments added in 2010, in order to reflect the new tighter budget in test methods and equipment. The major changes are:

Launch and tail test cords with controlled end-faces.
Reference connectors with very low loss.
1-and 3-test cord methods for reference setting with LSPM devices.
2-test cord methods are not acceptable.
Introduction of encircled flux for accuracy of multimode light source.
Detailed procedures of LSPM and OTDR devices.

The main reason for these changes is accuracy and reliability. With a budget of 1.5dB for 40/100Gbps, a test tolerance of 1dB is not acceptable and testing with outdated or inaccurate equipment/methods doesn’t make sense.

In the end, both 1 and 3-test cord methods of reference setting provide standards-compliant results.

Synergy Telecoms courses cover testing of fibre as well as copper and utilising latest processes and technologies and latest industry info.