A nondestructive technique for the accurate alignment of the birefringent axes of high-birefringence optical fibers
at an arbitrary position is demonstrated by using an elasto-optic effect. Alignment accuracy of less than 0.5° is
achieved, and the slow and fast birefringent axes can be easily distinguished. A high-birefringence-fiber directional
coupler with less than -28 dB polarization cross coupling, constructed by using this technique, is described.