US 9,803,981 B2Granted

Optical passive resonator gyro with three beams

AssigneeThales

InventorsSylvain Schwartz, Gilles Feugnet, Fabien Bretenaker

Life of this patent

Estimating the term…

Loading patent…

Abstract

The general field of the invention is that of passive resonator gyros comprising an injection laser emitting an initial optical beam at a first frequency and a fiber optic cavity. The gyro according to the invention operates with three optical beams at three different optical frequencies. A first beam is injected in a first direction of rotation, the second and the third beam are injected in the contrary direction. The gyro includes three slaving devices maintaining each optical frequency at a specific mode of resonance of the cavity. The gyro includes means for measuring the frequency differences existing between the different frequencies. Combined together, these differences are representative of the length of the cavity and the angular rotational velocity of the cavity along an axis perpendicular to its plane.

Claims20

Dependent claims

Passive resonator gyro comprising an injection laser emitting an initial optical beam at a first frequency and a cavity,

Wherein the gyro includes:
an optical splitter configured to divide the initial optical beam into a first optical beam, into a second optical beam and into a third optical beam, the first beam being injected into the cavity in a first direction, the second and third optical beams being injected into the cavity in the opposite direction;
a first slaving device configured to slave the first frequency of the first optical beam to a first proper frequency corresponding to a first mode of resonance of the cavity or to slave a first proper frequency corresponding to a first mode of resonance of the cavity to the first frequency of the first optical beam;
a second slaving device configured to slave the second frequency of the second optical beam to a second proper frequency corresponding to a second mode of resonance of the cavity;
a third slaving device configured to slave the third frequency of the third optical beam to a third proper frequency corresponding to a third mode of resonance of the cavity, the three proper frequencies being all different from each other;
and
means for measuring a first frequency difference between the first frequency and the second frequency and for measuring a second difference between the second frequency and the third frequency, these two frequencies combined together being representative of the length of the cavity and the angular rotational velocity of the cavity along an axis perpendicular to the median plane of said cavity.

4 more elements

A method for operating a passive resonator gyro comprising an injection laser emitting an initial optical beam at a first frequency and a cavity, comprising:

using an optical splitter to divide the initial optical beam into a first, second, and third optical beams;
injecting the first beam being into the cavity in a first direction and injecting the second and third optical beams into the cavity in a second direction opposite direction the first direction;
using a first slaving device to slave the first frequency of the first optical beam to a first proper frequency corresponding to a first mode of resonance of the cavity or to slave a first proper frequency corresponding to a first mode of resonance of the cavity to the first frequency of the first optical beam;
using a second slaving device to slave a second frequency of the second optical beam to a second proper frequency corresponding to a second mode of resonance of the cavity;
using a third slaving device to slave a third frequency of the third optical beam to a third proper frequency corresponding to a third mode of resonance of the cavity, the first, second and third proper frequencies being all different from each other;
and
determining a length of the cavity and an angular rotational velocity of the cavity along an axis perpendicular to the median plane of the cavity based on a first frequency difference between the first frequency and the second frequency and a second difference between the second frequency and the third frequency.

4 more elements

Dependencies are inferred from the claim text.