Tunable photonic oscillator for efficient frequency generation

A frequency generation method comprising:

• coupling pump light into a coupled optical resonator, wherein the coupled optical resonator includes three or more coupled individual resonators supporting three or more split-resonant frequencies distributed with a split-frequency spacing, wherein the split-frequency spacing is determined by intracavity coupling between the three or more coupled individual resonators;
• generating comb light with the coupled optical resonator, wherein the comb light includes optical frequencies corresponding to the three or more split-resonant frequencies;
• and
• illuminating a photodetector with the comb light to generate an electrical signal with a frequency corresponding to the split-frequency spacing.

A frequency generator comprising:

• a coupled optical resonator, wherein the coupled optical resonator includes three or more coupled individual resonators supporting three or more split-resonant frequencies distributed with a split-frequency spacing, wherein the split-frequency spacing is determined by intracavity coupling between the three or more coupled individual resonators, wherein the coupled optical resonator includes one or more phase shifters to tune the split-frequency spacing by controlling the intracavity coupling between the three or more coupled individual resonators;
• at least one laser source to generate pump light having optical frequencies corresponding to at least one of the three or more split-resonant frequencies, wherein the coupled optical resonator receives the pump light and generates comb light having optical frequencies corresponding to the three or more split-resonant frequencies;
• a photodetector, wherein the photodetector receives the comb light and generates an electrical signal having a frequency corresponding to the split-frequency spacing of the coupled optical resonator;
• and
• a controller including one or more processors configured to execute program instructions causing the one or more processors to control the frequency of the electrical signal by generating control signals for the one or more phase shifters.