Methods and apparatus provide for birefringent waveguides suitable for
optical systems exhibiting polarization dependence such as interferometer
sensors including Sagnac interferometric fiber optic gyroscopes (IFOG).
The waveguides, for some embodiments, may offer single polarization
performance over lengths of about a kilometer or more due to polarization
dependent attenuation. According to some embodiments, the waveguides
incorporate a pure silica core for resistance to radiation-induced
attenuation (RIA).