What is dark fibre?

Testing dark fibre

Testing dark fibre

Full fibre characterisation is recommended for any dark fibre contract. Richard Ednay, OTT technical Director, wrote the definition of fibre characterisation that is in ITU G.650.3

ITU-T recommendation image and link

"A comprehensive suite of measurements that is carried out on an optical fibre cable link to determine the key performance attributes of that link which may affect current or future applications that operate over that link. Fibre characterization also allows the quality of the optical fibre cable link to be assessed, including the identification of the type and grade of fibre installed. Full fibre characterization includes connector end face inspection, insertion loss measurements, return loss measurements, OTDR testing, chromatic dispersion testing, polarization mode dispersion measurement, and spectral attenuation."

Performing all these measurements to produce accurate and reliable results is a skilled task in itself. Furthermore, the analysis and interpretation of the results to report on the quality of the fibre infrastructure and the ability of the link to support different applications and technologies also requires a lot of detailed knowledge.

OTT and CFCE logos and link

Optical Technology Training's Certified Fibre Characterisation Engineer (CFCE) programme has been setting the standard for competence in fibre characterisation since 2005. You should always make sure that your dark fibre characterisation is being carried out by an OTT certified CFCE.

The CFCE training programme is now licenced by OTT to our training delivery partners:


CrossConnect logo and link

CrossConnect Training in the UK and Ireland



Fiber Insight logo and link


Fiber Insight in North America




On these courses, you'll use fibre characterisation equipment from the world's leading test equipment manufacturers like EXFO and Viavi Solutions