Optically compensated polarization reciprocity in interferometric fiber-optic gyroscopes

Abstract

Polarization reciprocity is studied both theoretically and experimentally in an optically compensated configuration of interferometric fiber optic gyroscope (IFOG). In conventional IFOGs based on the minimal scheme, the output port of the coil coupler cannot be used mainly because of its polarization nonreciprocity (PN), and thus it is usually called the "nonreciprocal port". We show that the PN errors at the nonreciprocal port are effectively eliminated by optical compensation. With this unique property, the optically compensated IFOG can possess two low-PN ports for rotation sensing at the same time. From another perspective, one port IFOGs are possible to be constructed with less structural complexity.