Polarization mode coupling in circularly birefringent gratings.

Polarization mode coupling in circularly birefringent gratings is analyzed. It is numerically found that efficient LP01x-LP02y mode coupling (where LP is linear polarization) is possible in a 50-cm-long circularly birefringent fiber grating formed in a terbium-doped borosilicate glass fiber and that complete LP01x-LP02y and LP01x-LP03y mode couplings result after a few-centimeter-long circularly birefringent grating that is formed in a bismuth-substitute iron garnet waveguide. Various parameters of polarization mode coupling in a number of circularly birefringent gratings are also computed.