Systems and methods for effective relative intensity noise subtraction for a broadband resonator optical gyroscope

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 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;
• a second optical coupler coupled to the optical resonator, wherein the second optical coupler is configured to couple optical signals out of the optical resonator after the optical signals pass through the optical resonator in the first direction;
• a phase modulator configured to apply a phase modulation to optical signals that have been coupled out of the optical resonator by the second optical coupler to generate phase-modulated optical signals;
• an optical resonator filter configured to filter a first portion of the phase-modulated optical signals to generate filtered, phase-modulated optical signals;
• wherein the second optical coupler is configured to couple a second portion of the phase-modulated optical signals into the optical resonator such that the phase-modulated optical signals propagate in a 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;
• a relative intensity noise detector configured to convert the filtered, phase-modulated optical signals to first electrical signals indicative of a power level of the filtered, phase-modulated optical signals and relative intensity noise;
• a second photodetector configured to convert the phase-modulated optical signals after passing through the optical resonator in the second direction to second electrical signals indicative of a power level of the phase-modulated optical signals;
• and
• one or more circuits configured to determine a rate of rotation based on the first electrical signals and the second electrical signals.

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;
• applying a phase modulation to the optical signals coupled out of the optical resonator by the second optical coupler to generate phase-modulated optical signals;
• filtering, with an optical filter, a first portion of the phase-modulated optical signals to generate filtered, phase-modulated optical signals;
• generating, with a relative intensity noise detector, first electrical signals indicative of a power level of the filtered, phase-modulated optical signals and relative intensity noise;
• coupling, with the second optical coupler, a second portion of the phase-modulated optical signals into the optical resonator to propagate in a second direction;
• coupling, with the first optical coupler, 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;
• generating, with a second photodetector, second electrical signals indicative of a power level of the phase-modulated optical signals after passing through the optical resonator in the second direction;
• and
• determining a rotation rate based on the first electrical signals and the second electrical signals.