Two pump-frequency-stimulated Brillouin scattering ring laser gyroscope

A two-frequency ring laser gyroscope comprising:

• a pump laser;
• means for dividing the pump laser beam into two equal intensity beams;
• means for modulating the two derived beams to shift their frequencies to a different frequency from the pump beam and from each other;
• means for coupling the two-frequency-shifted beams into opposite ends of an optical fiber waveguide ring;
• an optical fiber waveguide ring to be used as a laser cavity;
• means for pumping the optical fiber waveguide cavity by the two derived beams in both the clockwise and counterclockwise directions simultaneously in order to excite stimulated Brillouin scattering in both directions around the ring;
• means for optically closing the ring on itself so that the stimulated Brillouin scattering results in two oppositely circulating Brillouin ring lasers;
• means for extracting a portion of each Brillouin ring laser beam and bringing the two extracted beams to a common point;
• means for mixing the two extracted beams together in a photodiode to produce a beat frequency proportional to the ring rotation rate about an axis perpendicular to the plane of the ring;
• means for measuring the magnitude of the beat frequency so derived;
• means for generating the electrical signals required to drive the laser beam modulators;
• and
• means for signal processing required to detect, amplify and filter the beat frequency signal.