High-capacity channel for higher speed passive optical networks

An optical line terminal (OLT) for downstream transmission in a passive optical network (PON), comprising:

• a processing device configured to:
• generate a first downstream signal for transmission on a first channel at a first signal level;
• and
• generate a second downstream signal for transmission on a second channel at a second signal level, wherein the first signal level is greater than the second signal level;
• and
• a physical medium dependent (PMD) transmitter configured to transmit a combined downstream signal comprising the first downstream signal and the second downstream signal,
• wherein a first transmit power of the first downstream signal is selected based on a comparison to a second transmit power of the second downstream signal to facilitate reception of the first downstream signal from the combined downstream signal at an optical network unit (ONU),
• wherein the processing device is further configured to compute, at the OLT, a transmit power increase and an extinction ratio increase when the combined downstream signal is transmitted.