How to calculate the total fiber line loss?
1- In the DWDM system, the power loss introduced by line fiber, optical modules, and optical components is needed to be compensated for by the optical amplifier (Erbium-doped fiber amplifier or Raman amplifier).
2- The method of counting fiber attenuation greatly affects system design. The following defines six rules of counting fiber attenuation, based on bidding documents.
3- If the margin is no less than 3 dB, neglect FIU insertion loss during power calculation.
There are 6 conditions to calculate the line loss :
1- If specific formula to calculate the fiber loss is provided, we use the following formula to calculate the fiber loss:Line loss = f(x) + FIU insertion loss and We consider FIU insertion loss = 0.9dB
2- If only line loss X is provided, we use following procedure to find the attenuation:Line loss = X + Margin + FIU insertion loss and Default Margin = 3dB.but If Margin≥3dB, neglect FIU insertion loss.
3- If the maximum loss of the fiber at the end of life is provided:Line loss = Max. loss + FIU insertion loss
4- If the distance and the attenuation coefficient with margin are provided:Line loss = Length x Coefficient + FIU insertion loss and Coefficient provided by customer.
5- If only the actual distance is provided:Line loss = Length x Default Attenuation Coefficient + Margin
+ Flange loss + FIU insertion loss and Default Attenuation Coefficient = 0.22dB/km, Default Margin = 3dB, Flange loss = 0.5dB/two flanges
6- If the actual distance less than 40km:Line loss = Length x Default Attenuation Coefficient + Margin
+ Flange loss + FIU insertion loss and Default Margin = 1.5dB
