FIG. 3 illustrates, by way of example, a logical block diagram of an embodiment of control circuitry.

FIG. 4 illustrates, by way of example, a diagram of an embodiment of beat generation circuitry.

FIG. 5 illustrates, by way of example, a flow diagram of an embodiment of a method for controlling an optical frequency comb generator.

FIG. 6 illustrates, by way of example, a block diagram of an embodiment of a machine on which one or more of the methods as discussed herein can be implemented.

Embodiments in this disclosure generally relate to generation of optical frequency combs.

Optical frequency combs may be used to generate ultra-low phase noise microwave signals, however, in order to do so they need to be finely controlled, or locked. Optical frequency combs may have two degrees of freedom. The first degree of freedom may be a repetition frequency, or repetition rate. The repetition rate controls the spacing between the teeth of the comb as well as the breadth of the comb. The second degree of freedom may be the carrier envelope offset. The carrier envelope offset shifts the frequency of the optical frequency comb teeth. In order to keep the optical frequency comb locked to a continuous-wave stable optical reference, the control system may control the two degrees of freedom by regulating two signals generated from the optical frequency comb, the beat tone and the carrier envelope offset frequencies. The beat tone corresponds to the repetition rate the carrier envelope offset frequencies correspond to an offset from a nominal frequency (e.g., zero).