Enhancement of power budget in RSOA based loop-back type WDM-PON by using the cascaded RSOAs

In the RSOA based remodulation WDM-PON link, the quality of the upstream performance largely depends on the downstream, such as downstream ER and the received optical power, which directly connected to the link power budget. By cascading RSOAs in the ONU, aforementioned link design constraints were alleviated; the link power budget can be increased by 10 dB when the downstream ER of 5 dB.