What is the power budget of the system? Wavelengths at or close to 1310nm suffer 0.4dB of attenuation
per kilometer while those at or near 1550nm experience 0.3dB of attenuation per kilometer. Bare in
mind, fiber links -particularly those that are leased- are often not a single piece of fiber but are commonly
made up of many pieces of fiber connected together through patch panels, connectors and splices.
Each patch, connector and splice attenuates the signal by approximately 0.5dB as well adding to the
total optical return loss of the system. Before designing a system the link budget and if possible the
optical return loss should be measured as theoretical attenuation values are often not representative of a
real fiber run.