Fiber optic gyroscope with front end polarizer

摘要

A fiber optic gyroscope (FOG) is provided. The FOG comprises a depolarizer that receives light from a light source, a multifunction integrated optic chip (MIOC) and a sensing coil coupled to outputs of the MIOC. The FOG also includes a polarizer coupled between an output of the depolarizer and an input of the MIOC. The polarizer mitigates polarization non-reciprocity (PNR) bias error and enhances the polarization extinction ratio (PER) of the FOG.

主权项

1. A fiber optic gyroscope (FOG) comprising: a depolarizer that receives light from a light source;
a multifunction integrated optic chip (MIOC); a sensing coil coupled to outputs of the MIOC; and an inline fiber polarizer comprising a fiber polarizer and a secondary polarizer, wherein the fiber polarizer is pigtailed to an output of the depolarizer and an input of the secondary polarizer, the secondary polarizer being pigtailed to an input of the MIOC, wherein a length of the secondary polarizer is selected based on a length of the depolarizer and a number of cross-couplings of the depolarizer such that a length of the optical path of the FOG corresponds to a minimum of a coherency function to reduce large amplitude polarization non-reciprocity (PNR) bias error associated with decoherent light waves from the depolarizer by minimizing effects on the FOG from the cross coupling and birefringence temperature sensitivities introduced by the depolarizer and to enhance the polarization extinction ratio (PER) of the FOG, and wherein the length of the secondary polarizer is selected such that the square root of the PER associated with the secondary polarizer is proportional to a reduction factor in PNR bias error based on the cross couplings and birefringence temperature sensitivities introduced by the depolarizer.