how does it work?

OTDR testing at a glance

Mapping your fibre plant

• Unlike the optical loss reports that you would obtain through insertion-loss testing (which provide accurate information about the attentuation, length and polarity of a fibre span) OTDR testing is used to certify the integrity of fibre plant.
• An OTDR device does this by sending a pulse down a fibre, and measuring return signals from fibre backscatter, reflections from connectors and loss from splices.
• The resulting "trace" or "signature" is represented by a series of events (e.g. spikes) on a visual display (see below for a typical example).
• What you're left with is a profile of your fibre length, where link components such as connectors and splices (as well as irregularities caused by the cable itself) are mapped for simplified location if remedial action is required.

when is OTDR testing used?

Practical examples of OTDR

Testing for faults in existing cabling

• You know you've got a problem somewhere along a cable... but, is it the cable itself? If yes, which part of it? Perhaps one of those bends is too sharp or there's a kink? Maybe it's a connector, or a splice where the signal is dropping off?
• OTDR testing turns a fault finding exercise from a tiresome, time-consuming guessing game, into a logical process. Following an OTDR trace, you'll be able to see what's happening where, right along the fibre length, allowing you to get straight to the source of the degradation.

Setting a quality benchmark for new cabling

• When you've completed an installation (or had one carried out for you) OTDR testing will provide certification of the integrity of your new cabling — that it's fault free, and delivers the performance that you need for the job it's going to do.
• Typically, these baseline traces are then archived for future reference.