Broadband resonator optical gyroscope with efficient optical power management for low shot noise

A resonator optical gyroscope, comprising:

• a broadband light source configured to generate optical signals having a broadband frequency range;
• an optical resonator;
• a first optical coupler coupled to the optical resonator, wherein the first optical coupler is configured to receive the optical signals from the broadband light source and couple the optical signals into the optical resonator such that the optical signals propagate in a first direction through the optical resonator, wherein the first optical coupler is also configured to couple the optical signals out of the optical resonator after the optical signals pass through the optical resonator in a second direction;
• a second optical coupler coupled to the optical resonator, wherein the second optical coupler is configured to couple the optical signals out of the optical resonator after the optical signals pass through the optical resonator in the first direction, wherein the second optical coupler is also configured to couple the optical signals into the optical resonator such that the optical signals propagate in the second direction through the optical resonator;
• one or more gain elements configured to amplify the optical signals that have been coupled out of the optical resonator by the second optical coupler and passed through the optical resonator in the first direction and/or the optical signals that have been coupled out of the optical resonator by the first optical coupler and passed through the optical resonator in the second direction;
• a photodetector configured to convert amplified optical signals to corresponding electrical signals based on a power level of the amplified optical signals;
• one or more circuits configured to determine a rate of rotation based on the corresponding electrical signals;
• a phase modulator;
• and
• either:
• (a) wherein the one or more gain elements include a first gain element configured to receive the optical signals coupled out of the optical resonator by the second optical coupler and to amplify the optical signals coupled out of the optical resonator by the second optical coupler to generate the amplified optical signals;
• wherein the phase modulator is configured to receive the amplified optical signals from the first gain element and apply a phase modulation to the amplified optical signals to generate phase-modulated, amplified optical signals;
• wherein the second optical coupler is configured to couple the phase-modulated, amplified optical signals into the optical resonator such that the phase-modulated, amplified optical signals propagate in the second direction through the optical resonator;
• wherein the first optical coupler is configured to couple the phase-modulated, amplified optical signals out of the optical resonator after the phase-modulated, amplified optical signals pass through the optical resonator in the second direction;
• (b) wherein the phase modulator is configured to receive the optical signals coupled out of the optical resonator by the second optical coupler and apply the phase modulation to the optical signals to generate phase-modulated optical signals;
• wherein the second optical coupler is configured to couple the phase-modulated optical signals into the optical resonator such that the phase-modulated optical signals propagate in the second direction through the optical resonator;
• wherein the first optical coupler is configured to couple the phase-modulated optical signals out of the optical resonator after the phase-modulated optical signals pass through the optical resonator in the second direction;
• wherein the one or more gain elements include the first gain element configured to receive the phase-modulated optical signals coupled out of the optical resonator by the first optical coupler and to amplify the phase-modulated optical signals to generate the phase-modulated, amplified optical signals;
• or
• (c) wherein the phase modulator is configured to receive the optical signals coupled out of the optical resonator by the second optical coupler and apply the phase modulation to the optical signals to generate the phase-modulated optical signals;
• wherein the one or more gain elements include a first gain element configured to receive the phase-modulated optical signals from the phase modulator and to amplify the phase-modulated optical signals to generate the phase-modulated, amplified optical signals;
• wherein the second optical coupler is configured to couple the phase-modulated, amplified optical signals into the optical resonator such that the phase-modulated, amplified optical signals propagate in the second direction through the optical resonator;
• wherein the first optical coupler is configured to couple the phase-modulated, amplified optical signals out of the optical resonator after the phase-modulated, amplified optical signals pass through the optical resonator in the second direction.

A method of operating a resonator optical gyroscope, comprising:

• generating, with a broadband light source, optical signals having a broadband frequency range;
• coupling, with a first optical coupler, the optical signals into an optical resonator to propagate in a first direction;
• coupling, with a second optical coupler, the optical signals out of the optical resonator after the optical signals pass through the optical resonator in the first direction;
• amplifying, with one or more gain elements, the optical signals coupled out of the optical resonator by the second optical coupler to generate amplified optical signals;
• coupling, with the second optical coupler, the amplified optical signals into the optical resonator to propagate in a second direction;
• coupling, with the first optical coupler, the amplified optical signals out of the optical resonator after the optical signals pass through the optical resonator in the second direction;
• generating, with a photodetector, electrical signals corresponding to the amplified optical signals;
• and
• determining a rotation rate based on the electrical signals.