Abstract: A laser gyro for detecting rates of rotating the gyro having a primary dither means for eliminating lock-in at low rates of rotation and a secondary dither means for eliminating nonlinearities in the gyro output when the input rate is a harmonic of the primary dither frequency. The gyro includes a body having a polygonal shaped cavity therein with a mirror disposed at each of the corners thereof to form a closed loop path for two counter-rotating beams. The primary dither includes means for dithering two mirrors 180.degree. out of phase to maintain the cavity path length constant. The secondary dither includes a current dither for differentially modulating the current in each leg of the gyro to randomly null nonlinearities in the gyro output.

Abstract: A cathode arrangement for a ring laser gyro. A metal cathode member is sunken into a bore disposed in the gyro body to provide a low profile cathode arrangement. An annular groove is formed at the bottom of the bore around the periphery thereof. The cathode member is suspended from a cover such that the lower edge of the cathode member is disposed in the annular groove, the cover being secured to the gyro body to provide a seal therebetween.