Methods and apparatus for achieving multiple bit rates in passive optical networks

An optical network unit (ONU) for use in a passive optical network employing multiple downstream bit rates, comprising:

• a media access control and data processing and operational control circuit;
• a serializer/deserializer operating at a clock rate compatible with a highest bit rate used in the passive optical network and producing deserialized output;
• and
• a downsampling module for translating the output of the serializer/deserializer to a lower bit rate data stream and providing the lower bit rate data stream to the media access control and data processing and operational control circuit.

A method of data communication comprising:

• performing a downstream data transmission from an optical line termination unit (OLT) to a plurality of optical network units (ONUs);
• as each of the ONUs receives a downstream transmission, achieving a phase and frequency lock of the operation of the ONU to a bit rate of the downstream transmission;
• changing the bit rate of the downstream transmission;
• and
• as the bit rate of the downstream transmission received at an ONU changes, maintaining a phase and frequency lock at the ONU to the downstream transmission.