Patent ID: 8582975

Claim:
An optical network unit (ONU) comprising: a port that receives a first optical signal and outputs a second optical signal; a first tap having first and second outputs, the first tap receiving the first optical signal from the port, the first output of the first tap supplying a first portion of the first optical signal, the second output of the first tap supplying a second portion of the first optical signal; an optical receiver circuit configured to receive the first portion of the first optical signal; a transmitter supplying an output optical signal, the output optical signal having a wavelength; a second optical tap having an input and first and second outputs, the first output of the second optical tap supplying a first portion of the output optical signal as the second optical signal, and the second output of the second optical tap supplying a second portion of the output optical signal; an optical coupler having first and second inputs and an output, the first input of the optical coupler receiving the second portion of the first optical signal and the second input of optical coupler receiving the second portion of the output optical signal, the output of the optical coupler supplying a combined optical signal including the second portion of the first optical signal and the second portion of the output optical signal; and a photodetector circuit configured to receive the combined optical signal and generate an electrical signal in response thereto; and a control circuit configured to adjust the wavelength of the output optical signal in response to the electrical signal.