Avoid channel and network errors
Minimum amount of allowable light loss

Optical Loss Budgets

Optical loss budgets are a critical component when designing a structured cabling topology. Do you know what your optical loss budgets are? Do you know why they are important?

If you don’t know, you could be experiencing channel or network errors and not understand why. The problem may be that you’re exceeding the optical loss budgets of your hardware.

An optical loss budget is the minimum amount of light loss allowable between two connected transceivers. This amount is determined by the standards bodies as well as the manufacturers of the electronics. Optical loss is measured in decibels (dB).

There are a number of important factors about fiber optic cables and light loss to keep in mind.

  • As hardware speeds increase, optical loss budgets decrease. Many times a hardware speed upgrade leads to errors from cabling that had worked previously, but cannot meet the loss budget of the new hardware.
  • Not all cabling is created equal. Many fiber assemblies have high dB loss. They may look just like any other assembly, but not perform as well as you need them to.
  • Some manufacturers use “typical” dB loss as a measurement in marketing materials. This is useless information for a budget as the assembly may not be “typical” and have higher loss amounts.

It is important to understand the basics of optical loss budgets and how the cabling you purchase can affect the hardware that it is plugging into.