Single-polarization fiber optic resonator for gyro applications

A novel fiber-optic resonant ring has been demonstrated that eliminates one of the orthogonal resonances in the cavity. Standard birefringent fiber resonators support two resonances, associated with the fast and slow eigenmodes of the resonator. The addition of an intercavity device increases the loss in one of the eigenmodes, thus squelching that resonance. We have fabricated resonant rings from birefringent fiber polished couplers with a length of polarizing fiber spliced into the cavity, which eliminates the orthogonal resonance, even for moderate amounts of subcomponent polarization cross-coupling. Resonators with deep, symmetric dips and with finesse of about 25 have been obtained, fabricated from adjustable and fixed polarization-maintaining couplers.