Optical gyroscope with broadband comb interrogation
Embodiments utilize an optical frequency comb generator coupled to an optical resonator of an optical gyroscope. The optical frequency comb generator generates an optical frequency comb having frequency peaks that each correspond to a respective resonance frequency of the optical resonator. A control servo can be coupled to the optical frequency comb generator and controls the optical frequency comb output from the optical frequency comb generator. In doing so, the optical frequency comb remains tuned to the resonance frequencies of the optical resonator during gyroscope operation.
1 . An optical gyroscope, comprising:
an optical resonator;
an optical frequency comb generator coupled to the optical resonator and configured to generate an optical frequency comb, wherein the optical frequency comb is locked to at least one of a plurality of resonance frequencies of the optical resonator;
wherein the optical resonator is configured to receive an optical signal from the optical frequency comb, wherein the optical signal propagates in the optical resonator in a first direction;
a reflecting element coupled to the optical resonator, wherein the reflecting element is configured to reflect the optical signal after propagating in the first direction,
wherein the optical resonator is configured to receive the reflected optical signal, wherein the reflected optical signal propagates in the optical resonator in a second direction opposite to the first direction; and
at least one processor coupled to the optical resonator, wherein the at least one processor is configured to determine an intensity corresponding to the reflected optical signal after propagating in the second direction, wherein the at least one processor is configured to determine a rotation rate based on the intensity corresponding to the reflected optical signal.
2 . The optical gyroscope of claim 1 , wherein the optical frequency comb comprises a plurality of frequency peaks, wherein each frequency peak overlaps with a respective resonance frequency of the optical resonator corresponding to propagation of the optical signal in the first direction.
3 . The optical gyroscope of claim 1 , comprising a control servo coupled to the optical resonator, wherein the control servo is configured to:
receive the optical signal after propagating in the first direction,
determine an intensity corresponding to the optical signal, and
configure the optical frequency comb generator based on the intensity corresponding to the optical signal,
wherein the optical frequency comb generator is configured to generate a modulated optical frequency comb in response to at least one control signal from the control servo.
4 . The optical gyroscope of claim 3 , wherein the optical resonator is configured for minimal frequency dispersion in a frequency range of the optical frequency comb.
5 . The optical gyroscope of claim 1 , comprising a laser source coupled to the optical frequency comb generator, wherein the laser source is configured to generate a pump signal, wherein the optical frequency comb generator is configured to generate the optical frequency comb from the pump signal.
6 . The optical gyroscope of claim 1 , wherein the optical frequency comb generator includes an electro-optic modulator or a Kerr optical comb generator.
7 . The optical gyroscope of claim 1 , comprising a Pound-Drever-Hall circuit, wherein the Pound-Drever-Hall circuit is configured to receive the optical signal from the optical resonator and to generate an error signal based on the optical signal, wherein the error signal represents a carrier frequency indicative of one of the resonance frequencies of the optical resonator, wherein the error signal causes the optical frequency comb generator to lock a frequency peak of the optical frequency comb to the carrier frequency.
8 . The optical gyroscope of claim 1 , comprising a relative intensity noise (RIN) servo coupled to the optical frequency comb generator, wherein the RIN servo is configured to receive the optical signal from the optical frequency comb generator and to modulate an intensity of the optical frequency comb based on an intensity of the optical signal.
9 . The optical gyroscope of claim 1 , comprising a phase modulator coupled to the optical resonator and the reflecting element, wherein the phase modulator is configured to generate phase-modulated optical signals from the reflected optical signals based on a phase modulation signal.
10 . A method for operating an optical gyroscope, the method comprising:
generating, from an optical frequency comb generator, an optical frequency comb, wherein the optical frequency comb is locked to at least one of a plurality of resonance frequencies of an optical resonator of the optical gyroscope;
coupling an optical signal from the optical frequency comb into the optical resonator, wherein the optical signal propagates in the optical resonator in a first direction;
reflecting the optical signal after propagating in the optical resonator in the first direction;
coupling the reflected optical signal into the optical resonator, wherein the reflected optical signal propagates in the optical resonator in a second direction opposite to the first direction;
determining a change in intensity from the optical signal and the reflected optical signal; and
determining a rotation rate based on the change in intensity.
11 . The method of claim 10 , wherein the optical frequency comb comprises a plurality of frequency peaks, wherein each frequency peak overlaps with a respective resonance frequency of the optical resonator corresponding to propagation of the optical signal in the first direction.
12 . The method of claim 10 , comprising:
receiving the optical signal after propagating through in optical resonator in the first direction,
determining an intensity corresponding to the optical signal, and
configuring the optical frequency comb generator based on the intensity corresponding to the optical signal,
wherein the optical frequency comb generator is configured to generate a modulated optical frequency comb in response to at least one control signal.
13 . The method of claim 12 , comprising controlling a repetition rate of the optical frequency comb based on the intensity corresponding to the optical signal.
14 . The method of claim 13 , comprising:
determining a free spectral range based on the intensity corresponding to the optical signal; and
setting the repetition rate of the optical frequency comb to the free spectral range.
15 . The method of claim 10 , comprising:
generating a Pound-Drever-Hall (PDH) error signal based on the optical signal, wherein the error signal represents a carrier frequency indicative of one of the resonance frequencies of the optical resonator; and
locking a tooth of the optical frequency comb to the carrier frequency.
16 . The method of claim 10 , comprising modulating an intensity of the optical frequency comb based on an intensity of the optical signal received from the optical frequency comb generator.