Fringe Contrast characterization and optimization for Ring Laser Gyroscopes

TL;DR

This paper presents a model for analyzing and optimizing fringe contrast in heterolithic ring laser gyroscopes, improving their sensitivity and data quality by addressing polarization, alignment, and non-planarity issues.

Contribution

It introduces a comprehensive model for fringe contrast that accounts for polarization and alignment effects, validated on the GP2 prototype.

Findings

Polarization corrections improve fringe contrast stability.

Model accurately characterizes polarization and non-planarity effects.

Optimization enhances gyroscope sensitivity and data reliability.

Abstract

Top sensitivity Ring Laser Gyroscopes based on a simple mechanical scheme, so called heterolithic, have shown to operate on a continuous basis; since the mirror positions are not fixed, unwanted signals can occur, and data selection is necessary. For this purpose, Fringe Contrast is very useful. It depends on output beams intensity, alignment, and polarization; the model of the alignment and polarization contributions to Contrast has been implemented, and tested on the GP2 prototype. Polarization changes are corrected by acting on the output beams with plates, in order to recombine linearly polarized light. Using such model, the GP2 prototype was characterized as for polarization of the beams, inside the cavity and at their interference, and for non-planarity; as a result, the interfering beams off-axis has also been measured.