Abstract: A synchronous fiber optic gyroscope includes a light source, an optical coupler in optical communication with the light source, an optical modulator in optical communication with the coupler, and a fiber optic coil in optical communication with the modulator. A detector is configured to receive an optical signal from the coupler and convert the optical signal to an electrical signal. A loop closure signal processor has a first input configured to receive the electrical signal from the detector. A phase lock loop has an output operatively connected to a second input of the processor. A direct digital synthesizer is operatively coupled to an input of the phase lock loop, with the synthesizer configured to generate a low-frequency signal that is transmitted to the phase lock loop. The phase lock loop converts the low-frequency signal to a high-frequency signal that is transmitted to the second input of the processor, and the phase lock loop provides signal modulation that is synchronous with signal demodulation.

Abstract: A resonator fiber optic gyroscope includes a first light source configured to generate a light signal. A resonator element is configured to generate an optical signal based on the light signal. A photodetector is configured to generate a first electrical signal based on the optical signal. The first electrical signal includes an oscillating signal, a direct-current (DC) signal, an even-harmonic signal including components at even harmonics of the oscillating signal, and an odd-harmonic signal including components at odd harmonics of the oscillating signal. A filtering element is configured to attenuate the DC signal, at least one even-harmonic component, and an odd-harmonic component to produce a second electrical signal. An amplifier is configured to amplify the second electrical signal. An analog-to-digital converter (ADC) is configured to digitize the amplified second electrical signal.

Abstract: A synchronous fiber optic gyroscope includes a light source, an optical coupler in optical communication with the light source, an optical modulator in optical communication with the coupler, and a fiber optic coil in optical communication with the modulator. A detector is configured to receive an optical signal from the coupler and convert the optical signal to an electrical signal. A loop closure signal processor has a first input configured to receive the electrical signal from the detector. A phase lock loop has an output operatively connected to a second input of the processor. A direct digital synthesizer is operatively coupled to an input of the phase lock loop, with the synthesizer configured to generate a low-frequency signal that is transmitted to the phase lock loop. The phase lock loop converts the low-frequency signal to a high-frequency signal that is transmitted to the second input of the processor, and the phase lock loop provides signal modulation that is synchronous with signal demodulation.

Abstract: A resonator fiber optic gyroscope includes a first light source configured to generate a light signal. A resonator element is configured to generate a optical signal based on the light signal. A photodetector is configured to generate a first electrical signal based on the optical signal. The first electrical signal includes an oscillating signal, a direct-current (DC) signal, an even-harmonic signal including components at even harmonics of the oscillating signal, and an odd-harmonic signal including components at odd harmonics of the oscillating signal. A filtering element is configured to attenuate the DC signal, at least one even-harmonic component, and an odd-harmonic component to produce a second electrical signal. An amplifier is configured to amplify the second electrical signal. An analog-to-digital converter (ADC) is configured to digitize the amplified second electrical signal.