Self-locked operation of large He-Ne ring laser gyroscopes

Helium-neon ring laser gyroscopes have been observed to produce a stable and useful Sagnac beat signal while operating with multiple longitudinal modes through a mode-locking mechanism. The parameter space pertaining to stable operation with respect to gas pressure and intra-cavity power has been explored experimentally. Two regions of stability have been identified. The stability of large ring lasers operating with mode-locking has been characterized. Mode-locked operation presents no statistically significant difference in performance compared with single-mode operation. It is shown that the time required for establishing stable mode-coupled operation can be a practical disadvantage for the ultra-large ring lasers.