Power-dependent correction to the scale factor in the laser gyro

Scale factor experiments were performed using an internal-mirror quartz-block 1.15-μm He-Ne laser, having a cavity length of 9.868 cm. The configuration was an equilateral triangle and the nominal geometric scale factor was
1.035 \times 10^{5}
counts per revolution. To avoid lock-in (20°/s) the laser was rotated at rates of
5000-9000\deg
/s. Using an equal mixture of neon isotopes, the scale factor was measured as a function of frequency tuning and, at the peak power frequency, as a function of discharge current. At the peak power frequency, the relative scale factor was reduced by 0.3 percent over the value found off the center. The slope of the relative scale factor variation was -0.03 percent per percent gain. To explain the experimental results, both radiation trapping and a strong signal theory were needed. Calculations showed a strong scale factor variation with loss that was ∼414 times the gain variation.