What does OTDR testing prove?

Detailed answer

What this means for your project

An OTDR trace is particularly useful for documenting route length and locating discrete events. It does not automatically replace every other acceptance test: projects may also require end-to-end insertion-loss measurements, polarity checks or application-specific certification. Launch and receive fibres, wavelengths, direction of testing and pass/fail criteria should be agreed before work begins. LGN provides test evidence matched to the identifiers used at each endpoint.

The appropriate specification and delivery method still depend on the site, programme and evidence available. LGN can review those constraints before recommending a practical next step.

What appears on an OTDR trace

An OTDR launches light into the fibre and measures returned energy over distance. The trace can identify connectors, splices, reflective events, bends, breaks and sections of abnormal attenuation. It also provides route-length evidence that helps locate a fault.

What OTDR does not prove by itself

• That both transmit and receive directions meet the application loss budget.
• That polarity is correct through every cassette and patching point.
• That connector end faces are clean and suitable for service.
• That the chosen optics and fibre type are compatible.

Agreeing a meaningful test plan

Wavelengths, test direction, launch and receive fibres, event thresholds and pass criteria should be defined before testing. Some projects also require light-source and power-meter insertion-loss results. LGN maps traces and results to endpoint identifiers so the evidence supports acceptance and future fault finding rather than existing as anonymous files.