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A hollow optical waveguide is proposed in which light can be confined in an air gap between a distributed Bragg reflecting (DBR) mirror and a high-index-contrast grating (HCG) mirror. Because of the combined effect of vertical (DBR) and lateral (HCG) periodicity, the proposed hollow waveguide shows a small modal birefringence on the order of 10-4 . In addition, a patterned HCG is shown to provide 2-D optical confinement, which is an important requirement for practical compact photonic devices. The proposed hollow waveguide is fabricated, and a low birefringence of 5 times 10-4 is demonstrated experimentally.