A resonator fiber optic gyroscope, comprising: a first mode-locked light source configured to produce a first light beam having a first frequency comb spectrum; a second mode-locked light source configured to produce a second light beam having a second frequency comb spectrum; a first optical filter in optical communication with the first mode-locked light source and configured to pass a first frequency comb portion of the first frequency comb spectrum, the first frequency comb portion having a free spectral range value, wherein the first frequency comb portion is modulated at a first frequency; a second optical filter in optical communication with the second mode-locked light source and configured to pass a second frequency comb portion of the second frequency comb spectrum, the second frequency comb portion having a free spectral range value, wherein the second frequency comb portion is spectrally separated apart from the first frequency comb portion, wherein the second frequency comb portion is modulated at a second frequency that is different from the first frequency; and an optical resonator in optical communication with the first and second optical filters, the optical resonator having a plurality of resonances with a free spectral range value, the optical resonator comprising an optical fiber coil and configured to: circulate the first frequency comb portion through the optical fiber coil in a first counter-propagating direction; and circulate the second frequency comb portion through the optical fiber coil in a second counter-propagating direction; wherein the first frequency comb portion is locked to clockwise resonances of the optical resonator; wherein the second frequency comb portion is locked to counter-clockwise resonances of the optical resonator that are different from the clockwise resonances; wherein a first signal based on the modulated first frequency comb portion, from the optical resonator, is detected and demodulated, wherein a second signal based on the modulated second frequency comb portion, from the optical resonator, is detected and demodulated; wherein the free spectral range values of the first and second frequency comb portions are substantially the same and are adjusted to be an odd integer multiple of the free spectral range value of the resonances; wherein a frequency difference between the counter-propagating first and second frequency comb portions is proportional to a rotation rate of the gyroscope; wherein the second frequency comb portion is spectrally separated apart from the first frequency comb portion by a multiple of the free spectral range value of the resonances plus a frequency value proportional to the rotation rate. a first mode-locked light source configured to produce a first light beam having a first frequency comb spectrum; a second mode-locked light source configured to produce a second light beam having a second frequency comb spectrum; a first optical filter in optical communication with the first mode-locked light source and configured to pass a first frequency comb portion of the first frequency comb spectrum, the first frequency comb portion having a free spectral range value, wherein the first frequency comb portion is modulated at a first frequency; a second optical filter in optical communication with the second mode-locked light source and configured to pass a second frequency comb portion of the second frequency comb spectrum, the second frequency comb portion having a free spectral range value, wherein the second frequency comb portion is spectrally separated apart from the first frequency comb portion, wherein the second frequency comb portion is modulated at a second frequency that is different from the first frequency; and an optical resonator in optical communication with the first and second optical filters, the optical resonator having a plurality of resonances with a free spectral range value, the optical resonator comprising an optical fiber coil and configured to: circulate the first frequency comb portion through the optical fiber coil in a first counter-propagating direction; and circulate the second frequency comb portion through the optical fiber coil in a second counter-propagating direction; circulate the first frequency comb portion through the optical fiber coil in a first counter-propagating direction; and circulate the second frequency comb portion through the optical fiber coil in a second counter-propagating direction; wherein the first frequency comb portion is locked to clockwise resonances of the optical resonator; wherein the second frequency comb portion is locked to counter-clockwise resonances of the optical resonator that are different from the clockwise resonances; wherein a first signal based on the modulated first frequency comb portion, from the optical resonator, is detected and demodulated, wherein a second signal based on the modulated second frequency comb portion, from the optical resonator, is detected and demodulated; wherein the free spectral range values of the first and second frequency comb portions are substantially the same and are adjusted to be an odd integer multiple of the free spectral range value of the resonances; wherein a frequency difference between the counter-propagating first and second frequency comb portions is proportional to a rotation rate of the gyroscope; wherein the second frequency comb portion is spectrally separated apart from the first frequency comb portion by a multiple of the free spectral range value of the resonances plus a frequency value proportional to the rotation rate.