The ultra-long-haul optical transmission technology increases the span between optical sites. This will reduce the number of optical relay sites, which can lower engineering cost and OPEX, and improve system reliability.
In optical network design, the total loss of optical power must be calculated to ensure that performance of the optical transmission span meets requirements.
- Optical power budget (dB) + Design margin (3 dB) <= Pout (dB) - Pin(dB)
- L(km) x a (dB/km) + Design margin (3 dB) <= Pout (dBm) -Pin (dBm)
a = the optical fiber loss coefficient. For a G652/G655 optical fiber, a takes the value of 0.275 dB/km (generally, the value ranges from 0.2 to 0.3 dB/km).
