US-12618674-B2 - Interferometric resonator optical gyroscope with optical frequency comb

US12618674B2US 12618674 B2US12618674 B2US 12618674B2US-12618674-B2

Abstract

An interferometric resonator optical gyroscope includes an optical frequency comb generator configured to generate an optical frequency comb. Optical signals representative of the optical frequency comb pass through an optical resonator in different directions, and a rotation rate is determined based on the extent of interference between the optical signals. Parameters of the optical frequency comb generator can be controlled by a control servo based on an intensity of the optical signals after propagating in the optical resonator. Utilizing an optical frequency comb generator reduces the bias error during gyroscope operation.

Inventors

Jianfeng Wu
Steven Tin
Matthew Wade Puckett
Tiequn Qiu

Assignees

HONEYWELL INTERNATIONAL INC.

Dates

Publication Date: 20260505
Application Date: 20230914

Claims (10)

1 . An interferometric resonator optical gyroscope, comprising: an optical frequency comb generator configured to generate an optical signal, wherein the optical signal is representative of an optical frequency comb; at least one optical coupler, wherein the at least one optical coupler is configured to split the optical signal into a first optical signal and a second optical signal; an optical resonator coupled to the at least one optical coupler and configured to receive the first optical signal and the second optical signal, wherein the first optical signal propagates through the optical resonator in a first direction, wherein the second optical signal propagates through the optical resonator in a second direction; and a rate calculation circuit coupled to the optical resonator, wherein the rate calculation circuit is configured to: determine phase shift between the first optical signal and the second optical signal; and determine a rotation rate based on the phase shift; a control servo comprising at least one processor coupled to the optical frequency comb generator, wherein the control servo is configured to: determine at least one parameter of the optical frequency comb generator based on an intensity noise of the first optical signal or the second optical signal, and control the optical frequency comb generator based on the at least one parameter; a first relative intensity noise (RIN) detector and a second RIN detector coupled to the optical resonator; wherein the first RIN detector is configured to receive the first optical signal after propagating in the optical resonator, and to determine the intensity noise of the first optical signal; wherein the second RIN detector is configured to receive the second optical signal after propagating in the optical resonator, and to determine the intensity noise of the second optical signal; wherein one of the first RIN detector and the second RIN detector is configured to provide the intensity noise of the first optical signal or the second optical signal to the control servo.
2 . The interferometric resonator optical gyroscope of claim 1 , comprising a first phase modulator and a second phase modulator coupled to the at least one optical coupler, wherein the first phase modulator and the second phase modulator are respectively configured to modulate a phase of the first optical signal and the second optical signal; and to provide the first optical signal and the second optical signal to the optical resonator.
3 . The interferometric resonator optical gyroscope of claim 1 , comprising a detector coupled to the control servo, wherein the detector is configured to: receive the first optical signal or the second optical signal; convert the first optical signal or the second optical signal to an electric signal; and provide the electric signal to the control servo, wherein the control servo is configured to control the optical frequency comb generator based on an intensity of the electric signal.
4 . The interferometric resonator optical gyroscope of claim 1 , wherein the at least one optical coupler is configured to: receive the first optical signal and the second optical signal after propagating in the optical resonator; combine the first optical signal and the second optical signal; and provide the combined optical signal to the rate calculation circuit.
5 . A method for operating an interferometric resonator optical gyroscope, the method comprising: generating, with an optical frequency comb generator, an optical frequency comb; transmitting a first optical signal and a second optical signal from the optical frequency comb; coupling the first optical signal into an optical resonator in a first direction; coupling the second optical signal into the optical resonator in a second direction; coupling the first and the second optical signals out of the optical resonator; determining a phase shift between the first and the second optical signals; determining a rotation rate based on the phase shift; determining an intensity of the first optical signal or the second optical signal after propagating in the optical resonator; determining that the intensity is outside a set level; determining adjusted parameters of the optical frequency comb in response to determining that the intensity is outside the set level; and controlling the optical frequency comb generator with the adjusted parameters.
6 . The method of claim 5 , further comprising: determining at least one parameter of the optical frequency comb generator based on the intensity of the first optical signal or the second optical signal; and controlling the optical frequency comb generator based on the at least one parameter.
7 . The method of claim 6 , wherein determining the at least one parameter comprises determining a carrier envelope offset frequency and a repetition rate of the optical frequency comb, and further comprises tuning the optical frequency comb based on the carrier envelope offset frequency and the repetition rate.
8 . The method of claim 6 , wherein determining the at least one parameter comprises determining a repetition rate of the optical frequency comb, and further comprising: setting the repetition rate of the optical frequency comb to a free spectral range of the optical resonator or an integer multiple of the free spectral range.
9 . The method of claim 5 , wherein generating the optical frequency comb comprises generating an optical frequency comb with a Kerr frequency comb generator or a single frequency laser coupled with an electro-optic modulator.
10 . The method of claim 5 , wherein generating the optical frequency comb comprises: generating an optical signal having a single frequency; and generating the optical frequency comb from the optical signal having the single frequency.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with Government support under DOTC-19-01-INIT1141 awarded by Army. The Government has certain rights in the invention. BACKGROUND Resonator fiber optic gyroscopes (RFOGs) typically utilize narrow linewidth laser sources to generate the optical signals necessary for determining rotation rate measurements. An RFOG generally operates by propagating the optical signals generated by the laser through an optical resonator in counter-propagating directions. The signals output by the optical resonator may be frequency-shifted due to the Sagnac effect when the RFOG experiences a rotation about its sense axis; this frequency-shift between the two output signals can then be used to determine the extent of rotation experienced by the RFOG. However, signals generated by narrow linewidth lasers are more susceptible to the optical Kerr effect, which is a nonlinear optical phenomenon that modifies the propagation properties of the optical signal as a function of the intensity of the optical signal. As a result of the optical Kerr effect, the optical signals may lose power in the RFOG, thereby contributing to a loss of power efficiency. Additionally, the power loss may be so great that the signals may not be detectable after propagation in the optical resonator. SUMMARY The details of one or more embodiments are set forth in the description below. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Thus, any of the various embodiments described herein can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications as identified herein to provide yet further embodiments. In one embodiment, an interferometric resonator optical gyroscope is disclosed. The interferometric resonator optical gyroscope comprises an optical frequency comb generator configured to generate an optical signal. The optical signal is representative of an optical frequency comb. The interferometric resonator optical gyroscope comprises at least one optical coupler. The at least one optical coupler is configured to split the optical signal into a first optical signal and a second optical signal. The interferometric resonator optical gyroscope comprises an optical resonator coupled to the at least one optical coupler and configured to receive the first optical signal and the second optical signal. The first optical signal propagates through the optical resonator in a first direction. The second optical signal propagates through the optical resonator in a second direction. The interferometric resonator optical gyroscope comprises a rate calculation circuit coupled to the optical resonator. The rate calculation circuit is configured to determine an extent of interference between the first optical signal and the second optical signal. The rate calculation circuit is configured to determine a rotation rate based on the extent of interference. In one embodiment, a method for operating an interferometric resonator optical gyroscope is disclosed. The method comprises generating, with an optical frequency comb generator, an optical frequency comb. The method comprises transmitting a first optical signal and a second optical signal from the optical frequency comb. The method comprises coupling the first optical signal into an optical resonator in a first direction. The method comprises coupling the second optical signal into the optical resonator in a second direction. The method comprises coupling the first and second optical signals out of the optical resonator. The method comprises determining an extent of interference between the first and second optical signals. The method comprises determining a rotation rate based on the extent of interference. In yet another embodiment, a program product is disclosed. The program product comprises a non-transitory processor-readable medium on which program instructions configured to be executed by at least one processor are embodied. By executing the program instructions, the at least one processor is configured to receive a signal corresponding to an optical signal after propagating in an optical resonator of an interferometric resonator optical gyroscope. The at least one processor is configured to determine an intensity corresponding to the signal. The at least one processor is configured to determine at least one parameter of an optical frequency comb based on the intensity. The at least one processor is configured to control an optical frequency comb generator of the interferometric resonator optical gyroscope used to generate the optical frequency comb based on the determined at least one parameter. BRIEF DESCRIPTION OF THE DRAWINGS Understanding that the drawings depict only exemplary embodiments and are not therefore to be considered