Patent ID: 8514401

Claim:
An all-fiber interferometric fiber optic gyroscope comprising: a light source; a light detector; a fiber optic loop coupler; a polarization maintaining fiber optic loop coupled to the fiber optic loop coupler; and a light source coupler coupled between the light source and the fiber optic loop coupler and coupled between the light detector and the fiber optic loop coupler, the light source coupler having a plurality of ports and further having a plurality of transmission arms and a plurality of coupling arms defined between pairs of the ports; wherein the light source coupler is constructed so as to split input light, wherein a transmission arm of the plurality of transmission arms has a first light propagation characteristic that results in polarization of an optical signal propagated along said transmission arm and wherein the coupling arms each have a second light propagation characteristic that results in no polarization of an optical signal propagated along any of the coupling arms, wherein there is no polarizer between the light source coupler and the fiber optic loop coupler along the transmission arm of the light source coupler.