Patent ID: 7333736

Claim:
A method of controlling a phase delay between first and second drive signals being applied to first and second arms of a dual-arm modulator of a pulse carver in an optical transmitter, the method comprising: converting a portion of an optical output signal being output by the optical transmitter to an electrical signal; multiplying the electrical signal by a ½ rate clock signal, wherein the ½ rate clock signal is synchronous to and ½ the rate of a data clock of the optical transmitter to generate a frequency component proportional to a level of the ½ rate clock present in the optical spectrum of the optical output signal; low pass filtering the frequency component proportional to the level of the ½ rate clock present in the optical spectrum to minimize high-frequency waveforms; integrating the low pass filtered frequency component to generate a phase error; and controlling the phase delay between first and second drive signals being applied to first and second arms of the dual-arm modulator of the pulse carver based on the phase error between the first and second arms of the dual-arm modulator of the pulse carver.