Litton Systems, Inc.

Laurence G Cote

Donald A Frederick

Edward Kanegsberg

Disclosed herein is an apertureless ring laser gyroscope which achieves higher order transverse mode suppression without the use or need for a restrictive aperture that can be a source of unwanted scatter. Such mode suppression is achieved by operating the ring laser gyroscope in a higher pressure range (from 12 to 18 torr) than the range normally considered for ring laser gyroscope operation. Through the mechanism of pressure broadening and mode competition, the lower order TEM.sub.00 mode remains the only transverse mode present in the optical cavity of the ring laser gyroscope.

Ring laser gyroscope with a non-loss inducing mode suppression mechanism

Disclosed herein is a ring laser gyroscope having a non-reciprocal polarization rotation device such as a Faraday rotator configured to provide, through use of a Faraday magnet, a relatively uniform magnetic field across the profile of the Faraday rotator. By providing a uniform magnetic field across the diameter of the Faraday rotator, the magnetic lensing effects are reduced and the thermal sensitivity of the gyroscope's bias is substantially reduced.

Faraday magnet for the reduction of multi-oscillator bias thermal

A ring laser gyro is shown having a mirror designed for maximum reflectivity of parallel and perpendicularly polarized light at a frequency slightly greater or less than the frequency of the laser. In this configuration, the reflection of the preferred perpendicularly polarized light is reduced but slightly, while the reflection of the less desirable parallel polarized light is reduced significantly.

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Thousand Oaks, CA, United States of America

Laurence G Cote