HCIP Transmission Changed H31-341_V2.5 Questions

The EDFA (Erbium-Doped Fiber Amplifier) amplifies optical signals but also introduces Amplified Spontaneous Emission (ASE) noise, making it the primary noise source in optical transmission systems.

In an OA (Optical Amplifier) system, the lower threshold of the receive optical power for a line board with a PIN receiver or the WDM side of an OTU board is typically the optical module’s receiver sensitivity plus 3 dB, not 5 dB. Adding 3 dB accounts for margin to ensure reliable reception without unnecessary overdesign. The 5 dB margin usually applies when an APD receiver is used, which is more sensitive but also more susceptible to noise. Thus, for PIN receivers, HCIP-Transmission guidelines specify the lower threshold as sensitivity plus 3 dB to maintain signal quality while preventing false alarms or unnecessary protection switching.

All listed statements are disadvantages of FOADM compared to ROADM: it requires site visits for capacity or service changes, has poor wavelength flexibility due to fixed allocation, demands manual power budget adjustments onsite during expansion, and cannot provision wavelength services rapidly.

In OA-free systems, where no optical amplifiers are used, the lower threshold of the receive optical power of a line board or the WDM side of an OTU board is indeed the optical module’s receiver sensitivity plus 3 dB. This ensures a safety margin for stable signal reception and alarm triggering. Without optical amplifiers, signal levels are more susceptible to attenuation, so maintaining this margin helps prevent degradation due to low optical power. HCIP-Transmission highlights this threshold as a standard parameter for optical power management in non-amplified systems.