In Embodiment 4, the subject matter of any one or more of Embodiments 1-3 optionally include wherein the repetition rate control circuit includes: integral-lead control circuitry configured to apply integral-lead control to the beat tone error and provide an integral-lead repetition rate control; fast repetition rate control circuitry configured to apply proportional gain control and a frequency-to-voltage conversion to the integral-lead repetition rate control to provide the fast repetition rate control; and slow repetition rate control circuitry configured to apply proportional gain control, integration control, and a frequency-to-voltage conversion to the integral-lead repetition rate control to provide the slow repetition rate control.

In Embodiment 5, the subject matter of any one or more of Embodiments 1-4 optionally include wherein the carrier envelope offset control circuit includes: integral-lead control circuitry configured to apply integral-lead control to the beat tone error and provide an integral-lead carrier envelope offset control; fast carrier envelope offset control circuitry configured to apply proportional gain control and a frequency-to-voltage conversion to the integral-lead carrier envelope offset control to provide the fast carrier envelope offset control; and slow carrier envelope offset control circuitry configured to apply proportional gain control, integration control, and a frequency-to-voltage conversion to the integral-lead carrier envelope offset control to provide the slow carrier envelope offset control.

In Embodiment 6, the subject matter of any one or more of Embodiments 1-5 optionally include an optical frequency comb generator to use the fast repetition rate control, the slow repetition rate control, the fast carrier envelope offset control, and the slow carrier envelope offset control to provide a locked optical frequency comb.