Comparison of Quasi-four-frequency and Four-frequency Zeeman Laser Gyros with Different Types of Biasing

Among laser gyros, being the most precise inertial sensors nowadays, multi-oscillator laser gyros of a new generation are especially promising. Instead of mechanical biasing for eliminating frequency lock-in, they use physical optical methods, increasing their accuracy and resistance to external mechanical impacts. Here we consider Zeeman laser gyros, whose important advantage is the "pure optical path" (without intra-cavity elements). Two modifications of such laser gyros are considered – quasi-four-frequency and four-frequency. The results of experimental measurements of the input-output characteristics with different types of rectangular alternating frequency biasing are presented: with a single biasing (meander) and with a combined biasing (two different meanders). Comparative results confirm the advantages of the combined frequency biasing, improving the linearity of the input-output characteristic by 4 times.