Test at different wavelengths: Fibre loss can vary depending on the wavelength used. Measure at 850nm (for short-range) and 1310nm or 1550nm (for longer distances). Use a reference cable: This helps ensure your measurements are accurate by compensating for any inherent. To be able to judge whether a fiber optic cable plant is good, one does a insertion loss test with a light source and power meter and compares that to an estimate of what is a reasonable loss for that cable plant. The estimate, called a "loss budget" is calculated using typical component losses for. An Optical Time Domain Reflectometer (OTDR) sends light pulses through a fibre optic cable. These pulses travel down the fibre and reflect when they encounter inconsistencies, like breaks, splices, or bends. The longer the cable, the more a signal is reduced (or attenuated) by the time it reaches the far end. There are various causes of fiber optic loss, such as absorption/scattering of light energy by fiber material, bending loss, connector loss, etc.
[PDF Version]