Rockwell International Corporation

Northrop Corporation

James P Hauck

Cecil L Hayes

Wah L Lim

James D McMullen

Jack W Raquet

A ring laser gyro, having: an envelope for an optically resonant cavity having a gain bore section, the envelope containing an active gas medium. The envelope contains electrically energizable electrode means having at least two electrodes at electrode locations within the envelope for establishing an electrical discharge in an active gas medium between the electrode locations. The electrical discharge excites a pair of light beams along a lasting path between the electrode locations. The light beams counterpropagate in the optically resonant cavity. The envelope is coupled to means for generating an output signal for the gyro by measuring a difference in the frequencies of the light beams. The active gas medium has an axial current driven gas flow and a return gas flow induced by the electrical discharge, the resultant gas flow contributing to bias errors in the output signal. The envelope also comprises a gas bypass cavity adapted to pneumatically couple the electrode locations along the gain bore. The gas bypass cavity has a length adapted to inhibit ionization of the gas medium within the bypass cavity and also has a cross-section selected to reduce axial current driven gas flow between the respective electrode locations. The gas bypass cavity reduces the tendency of the ring laser gyro to exhibit bias errors by providing an alternate path for the return gas flow. The gas bypass cavity also operates to reduce the differential pressure between the respective electrode locations. The gas bypass cavity is equipped with a means for controlling the return gas flow.

Gas bypass for bias reduction in laser gyrescopes

A ring laser gyro, having: an envelope for an optically resonant cavity having a gain bore section, the envelope containing an active gas medium. The envelope contains electrically gain bore energizable electrode means having at least two electrodes at electrode locations within the envelope for establishing an electrical discharge in an active gas medium between the electrode locations. The electrical discharge excites a pair of light beams along a lasing path between the electrode locations. The light beams counter-propagate in the optically resonant cavity. The envelope is coupled to means for generating an output signal for the gyro by measuring a difference in the frequencies of the light beams. The active gas medium has an axial current driven gas flow and a return gas flow induced by the electrical discharge in the gain bore. The resultant gas flow contributes to bias errors in the output signal. The envelope also comprises a gas bypass cavity adapted to pneumatically couple the electrode locations along the gain bore. The gas bypass cavity also has a length in excess of that of the gain bore, and second electrode means for an auxiliary discharge path within the bypass cavity to provide axial current driven gas flow between the second electrode means respective electrode locations. Adjustment of the auxiliary discharge current provides a means for adjusting the gyro bias to compensate for bias errors induced by the gain bore axial current driven gas flow. The gas bypass cavity reduces the differential pressure between the respective electrode locations.

Ring laser gyro gas bypass with auxiliary discharge

A ring laser gyroscope incorporates a resonant cavity generally shaped as an irregular pentagon having a portion thereof conformed as three legs of a rectangle closed by two symmetrical other legs to form an apex. As result the enclosed area is increased, increasing sensitivity and decreasing lock-in, while magnetic effects are reduced. Additionally, the irregular shape allows for the extension of the gain medium which therefore increases the effectiveness thereof.

Pentagonal ring laser gyro design

Apparatus for generating a high-energy temporally shaped, coherent series of laser pulses having signal components on pre-selected rotational vibrational transitions, comprising: a waveguide laser array having an output comprising a desired temporally shaped coherent series of laser pulses on one pre-selected rotational vibrational transition, a second-harmonic generator arranged to double the waveguide laser array output frequency, a line matching laser array having a plurality of outputs of another temporal shape on additional rotational vibrational transitions, and means comprising an array of difference frequency mixers responsive to synchronized reception of line matching laser array outputs and said frequency doubled waveguide laser array output to form a corresponding high-energy, coherent series of laser pulses having a waveguide laser array output-determined temporal shape and line matching laser array output-determined rotational vibrational transitions.

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Santa Ana, CA, United States of America

James P Hauck