Patent ID: 7586619

Claim:
An optical gyro comprising: a sensing system configured to circulate counter-propagating light beams and further configured to produce an output light beam derived from said counter-propagating light beams; a coupler having first, second, third, and fourth ports, said coupler configured to receive an input light beam via said first port and further configured to supply said input light beam to said sensing system via said second port, said counter-propagating light beams derived from said input light beam; a first optical device having an input coupled to said third port of said coupler and having an output, said coupler further configured to direct a portion of said output light beam to said first optical device; a first detector coupled to said output of said first optical device and configured to detect a rotation rate of the optical gyro from said portion of said output light beam; a second optical device having an input coupled to said fourth port of said coupler and having an output, said coupler further configured to direct a portion of said input light beam to said second optical device; and a second detector coupled to said output of said second optical device and configured to detect noise in said portion of said input light beam, said first and second optical devices together configured to reduce a spectral mismatch between said portion of said output light beam and said portion of said input light beam.