A system for rotationally biasing a fiber optic gyroscope includes a fiber optic gyroscope assembly comprising a light source that emits an optical signal, an optical coupler in optical communication with the light source, and a fiber optic coil in optical communication with the light source. The fiber optic coil receives the optical signal through the optical coupler and imparts a phase shift proportional to rotation. A rate sensing detector in optical communication with the fiber optic coil receives the optical signal from the fiber optic coil through the optical coupler. A motor coupled to the fiber optic coil applies a periodic rotation to the fiber optic coil to impart a biasing phase modulation to the optical signal. A signal processing unit is coupled to the fiber optic gyroscope assembly and the motor. The signal processing unit converts a measured intensity of the optical signal to rotation rate data.

Embodiments described herein provide for a method of modulating an input light beam of an interferometric fiber optic gyroscope (IFOG). The method includes intermittently jumping a phase step to suppress dead band. During a first cycle, a first cycle raw rate is stored and a feedback signal is generated based on a jumped phase step. During a second cycle, a second cycle raw rate is stored and a feedback signal is generated based on the jumped phase step. During a third cycle, a third cycle phase step is generated by accumulating the first cycle raw rate with a second cycle phase step, and a feedback signal is generated from the third cycle phase step. During a fourth cycle, a fourth cycle phase step is generated by accumulating the second cycle raw rate with the third cycle phase step, and a feedback signal is generated from the fourth cycle phase step.

Embodiments described herein provide for a method of modulating an input light beam of an interferometric fiber optic gyroscope (IFOG). The method includes intermittently jumping a phase step to suppress dead band. If a bit flip was clocked into a digital to analog converter generating the feedback signal at the beginning of a cycle in which the jumped phase step is implemented, the method includes at least one of re-introducing a rate difference corresponding to the bit flip, altering the timing of the bit flip, or altering the timing of the generating a feedback signal based on the jumped phase step.

An optical gyroscope assembly for measuring a rotation rate. The optical gyroscope assembly includes a first multimode interferometer with an input for receiving light and two outputs, each connected to a second light guide; a ring resonator on each of the second light guides; a second multimode interferometer with two inputs, each connected to one of the second light guides, and two outputs, each connected to a third light guide; and a third multimode interferometer with two inputs, each connected to one of the third light guides, and two outputs, each connected to a fourth light guide.

A gyroscopic sensor unit detects a phase drift between a demodulated output signal and demodulation signal during output of a quadrature test signal. A delay calculator detects the phase drift based on changes in the demodulated output signal during application of the quadrature test signal. A delay compensation circuit compensates for the phase drift by delaying the demodulation signal by the phase drift value.

According to an embodiment, a circuit for quadrate error correction is proposed. The circuit includes a set of first resistors receiving a demodulated low-voltage differential signal from gyroscope sense electrodes; an ICMFB circuit with adjustable current sinks maintaining a low-voltage input level by controlling current; an HV driver circuit creating a high-voltage differential output from the low-voltage input, supplied to gyroscope correction electrodes; a set of second resistors where the input-to-output differential gain is defined by their relative resistances; and an output common-mode feedback circuit adapting the high-voltage output to a low-voltage for the HV driver.

A gyroscope comprises a source emitting a broadband beam, and a first waveguide arrangement that splits the beam into CCW and CW beams. First and second phase modulators are coupled to the waveguide arrangement and provide phase modulations or frequency shifts to the CCW and CW beams. An optical resonator is in communication with the phase modulators such that the CCW and CW beams are optically coupled into the resonator. A second waveguide arrangement receives the CCW and CW beams transmitted from the resonator. First and second RIN detectors are coupled to the second waveguide arrangement and respectively receive the CCW and CW beams. A rate detector receives the CCW and CW beams. A rate calculation unit receives intensity noise signals from the RIN detectors, and rate and intensity noise signals from the rate detector. The rate calculation unit performs a RIN subtraction technique to reduce intensity noise limited ARW.