Techniques are provided for diminishing bias error, in a resonator optical gyroscope, due to an undesired, parasitic optical mode which is orthogonal to a desired optical mode. Energy levels of the undesired, parasitic mode can be diminished utilizing polarizing beam splitters each of which suppresses energy of the undesired, parasitic mode of a clockwise or a counterclockwise optical signal more than energy of the desired mode of the CW optical signal. Optionally, one or more components of a travelling wave resonator system are configured to suppress energy of the undesired, parasitic mode of a clockwise and/or a counterclockwise optical signal more than energy of the desired mode of the respective optical signal(s). Optionally, the desired optical mode is either a transverse magnetic (TM) mode or a transverse electric (TE) mode, and the undesired, parasitic optical mode is respectively the TE mode or the TM mode.

Techniques are provided for implementing and using a high quality factor travelling wave resonator configured to propagate a transverse magnetic mode optical signals and suppress transverse electric mode optical signals. The travelling wave resonator may be used in a resonator optical gyroscope.

Methods and systems for measuring low speed angular rotation of a fiber optic gyroscope. A beam of light waves is split into a first path and a second path. The light waves of the second path are directed through a fiber circulator and split into a third and a fourth path. The third path and fourth path are coupled into opposite ends of an optical fiber coil to circulate clockwise and counterclockwise. Rotation of the fiber optic gyroscope generates a phase shift between the clockwise and counterclockwise light waves, which are recombined and fed back through the fiber circulator. The recombined waves are amplified, recirculated into the second path to increase the phase shift and transmitted along the first path to an optical spectrum analyzer which generates an interferogram. A microprocessor applies an FFT, measures the spacing of frequency components, and determines the angular rotation speed of the gyroscope.

A multi-layer detachable single-axis fiber optic sensing device is provided. The device includes a first circuit board, a light source module, an optical carrier, a beam guiding module, a modulation module, a fiber coil, a second circuit board, a detection module, a third circuit board, a transceiver module, a fourth circuit board, a power supply module, a fifth circuit board, and a computing module. The first circuit board, the optical carrier, the second circuit board, the third circuit board, the fourth circuit board, and the fifth circuit board may be arranged in any order, and any two adjacent ones can be detachably assembled together.

One example includes an optical system. The system includes a laser configured to generate an optical beam and an optical modulation system comprising a plurality of optical modulators arranged in a cascaded sequence. Each of the optical modulators can be configured to provide successive modulation of the optical beam in the cascaded sequence to provide a modulated optical beam. The system further includes an optical assembly configured to receive the modulated optical beam and to implement the modulated optical beam for an optical functional application.

A photonics gyroscope comprises a light source on a photonics chip that emits a broadband beam; a waveguide resonator; a reflective component; first and second detectors, the second detector coupled to the source; a RIN servo loop coupled between the second detector and the source; and a rate calculation unit. The beam is directed into the resonator such that it propagates in a CCW direction. A portion of the CCW beam is coupled out of the resonator toward the reflective component and reflected back as a reflected beam that is coupled into the resonator such that the reflected beam propagates in a CW direction. The CW beam is coupled out of the resonator to the first detector, which detects a resonance frequency shift between the CW and CCW beams. The RIN servo loop stabilizes an intensity of the beam such that bias error and noise is reduced.

A gyroscope comprises first and second light sources that emit first and second beams with broadband spectrums, and a waveguide arrangement that communicates with the light sources. A resonator communicates with the waveguide arrangement to receive the beams. A first circulator is coupled to the waveguide arrangement between the first light source and the resonator. A second circulator is coupled to the waveguide arrangement between the second light source and the resonator. A first rate detector communicates with the resonator through the first circulator, and a second rate detector communicates with the resonator through the second circulator. The rate detectors produce rate measurements based on a detected resonance frequency shift of the beams in the resonator caused by rotation of the gyroscope. Outputs of the rate detectors are used to calculate a rotation rate that is corrected for errors due to a time varying pathlength change in the resonator.

A method comprises providing an RFOG that includes a resonator in communication with a light source emitting a first signal at a first power level in a CW direction, and a light source emitting a second signal at a second power level in a CCW direction; adding a common intensity modulation to the first signal, to produce an intensity modulated CW signal; adding the same common intensity modulation to the second signal, to produce an intensity modulated CCW signal; introducing the intensity modulated CW signal into the resonator; introducing the intensity modulated CCW signal into the resonator; detecting modulated rate signals that are output from the resonator at a common intensity modulation frequency; and adjusting a power level ratio between the first and second power levels, to determine a modified power level ratio value where a Kerr effect bias instability due to an asymmetrical loss distribution is reduced or eliminated.

An optical resonator with increased free spectral range and substantially no increase in volume is provided. The optical resonator includes N winding optical waveguides where each n1 winding optical waveguide is within a corresponding n winding optical waveguide and N is an integer greater than one. The n1 and n winding optical waveguides are optically coupled by an optical coupler having substantially one hundred percent optical coupling.

Various examples of a closed-loop optical gyroscope are disclosed. The closed-loop optical gyroscope includes a broadband light source configured to generate broadband optical signal(s). The broadband optical signal(s) propagate in an optical resonator and are coupled in and out of the optical resonator by optical couplers. A phase modulator applies phase modulation to the optical signal(s) based on a sawtooth modulation signal. The optical signal(s) repropagate in the optical resonator in a different direction. The optical signal(s) are then received and analyzed to determine parameter(s) of the phase modulator. One or more processors configure the phase modulator based on the determined parameter(s).