Integrated triad optical rate sensor apparatus

A rate sensor for use in inertial reference systems to detect angular rotations and measure magnitudes and directional sense of the rates of angular rotations along a plurality of orthogonal axes, said rate sensor comprising:

• optical source means for generating an incoming optical source wave signal having a predetermined nominal wavelength;
• a plurality of gyroscope channels, each of said channels corresponding to one of said orthogonal axes and comprising:
• a passive ring path;
• splitting means for splitting said source wave signal into a pair of counter-propagating optical waves;
• path means for applying said counter-propagating optical waves through said associated ring path, wherein said counter-propagating optical waves emerge therefrom with a relative Sagnac phase shift indicative of the rate of angular rotation of said ring path;
• and
• combining means for recombining said counter-propagating waves into an outgoing optical wave signal, wherein the resultant low order fringe pattern is representative of the relative phases of said counter-propagating waves;
• detection circuit means connected to said gyroscope channels for generating an intensity signal indicative of said resultant low order fringe patterns;
• signal processing means connected to said detection circuit means and responsive to said intensity signal for generating output signals corresponding to said rates of angular rotation for each of said axes;
• and
• switch means connected to said gyroscope channels, said optical source means and said detection circuit means for selectively applying said source wave signal to a first one of said gyroscope channels during a first predetermined time period, and for applying said outgoing optical wave signal associated with a second one of said gyroscope channels to said detection circuit means during said first predetermined time period.