Systems and methods for providing intensity stabilization for a resonator fiber optic gyroscope

Patent metadata

Field	Value
Publication number	US-9354063-B2
Application number	US-201414266356-A
Country	US
Kind code	B2
Filing date	Apr 30, 2014
Priority date	Apr 30, 2014
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

Systems and methods for an intensity stabilized resonator fiber optic gyroscope are provided. In one embodiment, a method for providing optical intensity stabilization system for a resonator fiber optic gyroscope (RFOG) is provided. The method comprises: injecting a phase modulated light beam into a fiber optic ring resonator coil; measuring a DC component of the phase modulated light beam at an output of the fiber optic ring resonator coil; generating a feedback control signal based on the DC component; and attenuating the phase modulated light beam prior to injection into the fiber optic ring resonator coil by controlling a variable optical attenuator with the feedback control signal.

First claim

What is claimed is:

1. An optical intensity stabilization system for a resonator fiber optic gyroscope (RFOG), the system comprising:
a first variable optical attenuator configured to receive a first phase modulated light beam, wherein the first phase modulated light beam is phase modulated at a first modulation frequency, f m1 ;
a second variable optical attenuator configured to receive a second phase modulated light beam, wherein the second phase modulated light beam is phase modulated at a second modulation frequency, f m2 ;
a resonator ring coupled to receive the first phase modulated light beam from the first variable optical attenuator, and coupled to receive the second phase modulated light beam from the second variable optical attenuator;
a first intensity servo electrically coupled to the first variable optical attenuator, wherein the first intensity servo controls an attenuation applied by the first variable optical attenuator on the first phase modulated light beam based on an optical DC component of the first phase modulated light beam as measured by a first DC detector from a first output of the resonator ring; and
a second intensity servo electrically coupled to the second variable optical attenuator, wherein the second intensity servo controls an attenuation applied by the second variable optical attenuator on the second phase modulated light beam based on an optical DC component of the second phase modulated light beam as measured by a second DC detector from a second output of the resonator ring.

2. The system of claim 1 , wherein the resonator ring inputs the first phase modulated light beam at a first end of the resonator ring and inputs the second phase modulated light beam at a second end of the resonator ring such that the first phase modulated light beam and the second phase modulated light beam are counter propagating within the resonator ring.

3. The system of claim 1 , wherein the first detector is optically coupled to the first output of the ring resonator by a first polarization maintaining (PM) optical coupler and electrically coupled to the first intensity servo;
wherein the first DC detector outputs an electrical signal to the first intensity servo that varies as a function of the optical DC component of the first phase modulated light beam as measured from the first output of the resonator ring.

4. The system of claim 3 , wherein the second detector is optically coupled to the second output of the ring resonator by a second polarization maintaining (PM) optical coupler and electrically coupled to the second intensity servo;
wherein the second DC detector outputs an electrical signal to the second intensity servo that varies as a function of the optical DC component of the second phase modulated light beam as measured from the second output of the resonator ring.

5. The system of claim 1 , further comprising:
a first photo detector optically coupled to the first output of the ring resonator by a first polarization maintaining (PM) optical circulator;
a first trans-impedance amplifier coupled to the first photo detector; and
a first mixer coupled to the first trans-impedance amplifier and the first intensity servo;
wherein the first mixer outputs an electrical signal to the first intensity servo that varies as a function of the optical DC component of the first phase modulated light beam as measured by the first photo detector.

6. The system of claim 5 , wherein the first mixer demodulates a signal from the first trans-impedance amplifier at 2f m1 , twice the first modulation frequency, to generate the electrical signal to the first intensity servo.

7. The system of claim 5 , further comprising:
a second photo detector optically coupled to the second output of the ring resonator by a second polarization maintaining (PM) optical circulator;
a second trans-impedance amplifier coupled to the second photo detector; and
a second mixer coupled to the second trans-impedance amplifier and the second intensity servo;
wherein the second mixer outputs an electrical signal to the second intensity servo that varies as a function of the optical DC component of the second phase modulated light beam as measured by the second photo detector.

8. The system of claim 7 , wherein the second mixer demodulates a signal from the second trans-impedance amplifier at 2f m2 , twice the second modulation frequency, to generate the electrical signal to the second intensity servo.

9. The system of claim 5 , further comprising a second mixer coupled to the first trans-impedance amplifier and the second intensity servo;
wherein the second mixer outputs an electrical signal to the second intensity servo that varies as a function of the optical DC component of the second phase modulated light beam as measured by the first photo detector.

10. The system of claim 9 , wherein the second mixer demodulates the signal from the first trans-impedance amplifier at 2f m2 , twice the second modulation frequency, to generate the electrical signal to the second intensity servo.

11. The system of claim 1 , wherein the first intensity servo determines a first error between a desired reference optical DC light intensity and the optical DC component as measured from the first output of the resonator ring, and wherein the first intensity servo controls the attenuation applied by the first variable optical attenuator to drive the first error towards zero; and
wherein the second intensity servo determines a second error between a desired reference optical DC light intensity and the optical DC component as measured from the second output of the resonator ring, and wherein the second intensity servo controls the attenuation applied by the second variable optical attenuator to drive the second error towards zero.

Assignees

• Honeywell Int Inc

Inventors

• Sanders Glen A
• Strandjord Lee K
• Wu Jianfeng
• Qiu Tiequn

Classifications

• G01C19/727 Primary

  using a passive ring resonator · CPC title

• G01C19/721

  Details, e.g. optical or electronical details · CPC title