Polarization control in optical-fiber gyroscopes

Analysis indicates that strict attention must be paid to polarization control in fiber gyroscopes in order to ensure drift stability. It is shown that the maximum drift rate that is due to faulty polarization control is proportional to the amplitude-extinction ratio for the rejected polarization channel. Consequently, in the worst circumstances which on present evidence cannot be excluded, the intensity extinction for the rejected polarization channel in a typical fiber gyroscope must approach 10 to the -6th. Options for achieving this control are indicated by the analysis.