All-fiber interferometric fiber optic gyroscope having a minimum reciprocal configuration

A fiber optic gyroscope comprising:

• a light source;
• a detection unit;
• a fiber optic loop coupler;
• a polarization maintaining fiber optic loop, wherein the fiber optic loop coupler is coupled to the polarization maintaining fiber optic loop;
• and
• a light source coupler having a plurality of ports;
• wherein a first port of the light source coupler is coupled, with polarization axis alignment, to the light source, a second port of the light source coupler of the light source coupler is coupled to the detection unit;
• wherein a third port of the light source coupler is coupled, with polarization axis alignment, to the fiber optic loop coupler;
• the light source coupler including a fused-taper section having a radius and a length, wherein the radius and the length are such that a transmission arm defined between the first and third ports is capable of translating circularly polarized light or elliptically polarized light into linearly polarized light.

A fiber optic gyroscope comprising:

• a light source;
• a light source coupler having a plurality of ports;
• wherein a first port of the light source coupler is coupled to the light source;
• a detection unit coupled to a second port of the light source coupler;
• a fiber optic loop coupler directly coupled to a third port of the light source coupler;
• and
• a polarization maintaining fiber optic loop coupled to the fiber optic loop coupler;
• wherein the light source coupler has a transmission arm defined between the first and third ports and a coupling arm defined between the second and third ports;
• wherein the transmission arm has a first light propagation characteristic that results in polarization of an optical signal propagating along the transmission arm, and the coupling arm has a second light propagation characteristic that results in no polarization of an optical signal propagating along the coupling arm.