Collision broadening and quantum noise in a very large laser gyroscope

Abstract

The single mode and the multimode output power are studied as a function of the input power and the partial pressure in a very large (perimeter=14 m) He:Ne ring laser gyroscope and in a linear He:Ne laser (length=1.6 m). The effects of collision broadening on the single mode output power are discussed. For a sufficiently high He:Ne pressure, the gain of adjacent longitudinal modes is depleted and multimode emission is suppressed and hence the single mode output power of the ring laser is increased. The quantum noise and the long term drifts in the Earth rotation induced Sagnac frequency ( ν S=288.5 Hz) are investigated. The demonstrated advantages of operating a laser gyroscope at a large He:Ne pressure are: reduction in quantum noise and the freedom to choose the input power within a large range.