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CD-PMD Dispersion Testing

We are fully conversant with chromatic dispersion and polarisation mode dispersion testing, all our engineers are fully trained in this subject and hold valid CFCE Certified Fibre Characterisation Engineer qualification, approved by (OTT) Optical Technology Training. ​

Today’s modern day requires high bandwidth the use of fibre optic cable has advanced and is now a cost effective solution for all businesses and organisations. With this in mind fibre optic testing has become a critical part of installation tasks and requires expensive equipment to validate the network performance.

Fibre Optic Characterisation Testing

Chromatic & Polarisation Mode Dispersion Testing (CD/PMD)

Testing for chromatic and polarisation modes in a fibre network is a complex and requires qualified staff to characterise the fibre cables within a network to ensure high bandwidths can be achieved normally on Wavelength Division Multiplexed (WDM) using higher frequencies. Specialist equipment is needed for testing these modes on dark fibre networks for high capacity demanding circuits. As our staff are fully conversant with the testing regimes we are able to identify and characterise these fibre links and determine if the circuits are capable of running high bandwidth circuits as required.

OTDR Testing

OTDR stands for Optical Time Domain Reflectometer it is used by specialist trained personnel who have the ability to operate this machinery, OTDR's are used for testing and commissioning fibre networks before handover to the client. 


There is some misconception within the industry that training is not required unfortunately that isn't the case, individuals need training to use the equipment correctly and to interpret test results, and compiling test reports for the client.


OTDR's when setting up to the clients pass/fail criteria become a valuable asset for diagnosing issues found in a testing a link within the network. Our engineers are able to interpret test results and identify faults within a fibre optic network with the correct OTDR test equipment, we use multiple vendors, Viavi and Exfo. We are able to test short, medium and long-haul fibre networks

Bi-directional vs Uni-directional

Bidirectional testing should be completed when testing this normally means two members of qualified staff with a tester each connected to the same fibre, different vendors have different solutions normally testing A to B then B to A and compile test results, another solution is Viavi FCOMP which allows two testers to communicate with each other and perform true bidirectional testing and test to approved standard. Because of this technology you get a true loss in both directions in the test report. with other vendors you have to upload/merge test results and enter the values. our preferred method is Viavi FCOMP.

Insertion Loss Measurement (ILM)​ 

Insertion loss testing (ILM) should be carried out on all optical fibre networks, this is done using specialist test equipment and performed to industry standards, we have different types of ILM test equipment depending on the type of fibre cable. 

To discuss our fibre optic characterisation testing services please contact us on 01782 914001 or email us on info@tnscomms.co.uk or use the contact us page.

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