Simplified readout optics for a ring laser apparatus

Claim 1

A ring laser angular rate sensor comprising: a laser block for providing a ring laser path for first and second counter-propagating laser beams through interconnecting channels therein; and a readout having, a substrate including at least first, second, third surfaces, said first surface having portions thereof bonded to said block in proximity to said interconnecting channels, said second surface being at an acute angle relative to said first surface, beam splitter means, supported on said first surface, for reflecting a major portion of said first and second laser beams impinging on said beam splitter from one of said channels into an adjacent channel, for transmitting a smaller portion of said first beam into said substrate to exit through said third surface, and for transmitting a smaller portion of said second beam into said substrate toward said second surface, and reflection means, supported on said second surface, for reflecting a portion of said transmitted smaller portion of said second laser beam through said substrate to impinge on said beam splitter; said beam splitter means further comprising means for reflecting a portion of the beam reflected from the reflection means toward said third surface and adjacent to the portion of said first beam that is transmitted through said beam splitter means, and said acute angle is selected to cause said first and second beam portions to exit through said third surface and closely adjacent to each other to produce interference fringes.