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US 4,422,762 AGranted
Ring laser
AssigneeLitton Systems, Inc.
InventorsThomas J. Hutchings, Gary D. Babcock
Life of this patent
Estimating the term…
Abstract
A dithered ring laser particularly adapted for use as a gyro wherein backscatter from the mirrors is minimized by servoing the mirror inward and outward positions so that the sum of the AM amplitudes of the envelopes of the counterpropagating waves is reduced to a minimum value, then further servoing the mirrors to reduce the difference between such AM amplitudes.
Claims25
In combination:
- a ring laser, including a plurality of corner mirrors defining a ring laser path, transducers to control the inward and outward position of said mirrors, apparatus for detecting the AC amplitudes of the envelopes of two frequency modulated laser traveling waves counterpropagating along said laser path, apparatus for differentially dithering the laser path length, servo means for controlling the position of at least one said transducer and mirror to control and tune the length of the path of said laser;
- apparatus connected to said detecting apparatus for producing two signals which are measures of the AC amplitudes of the envelopes of said counterpropagating waves;
- summing means connected to receive said AC amplitude signals and to produce a sum signal which is a measure of the sum of said AC amplitude signals;
- and
- means for servoing the position of at least one of said transducers and mirrors to minimize said sum signal.
2 more elements
A method for reducing backscattering in dithered ring lasers having adjustable corner mirrors and
- transducers for positioning said mirrors, and having means for producing electrical signals which are measures of the low frequency AC component of the envelope of counterpropagating frequency modulated laser waves comprising;
- measuring the amplitudes of said electrical signals;
- additively combining said amplitudes;
- and
- adjusting the position of at least one of said transducers and mirrors to minimize the amplitude of the sum of said combined amplitudes.
2 more elements
Dependencies are inferred from the claim text.