Fiber-optic analogs of bulk-optic wave plates

The author's discovery of an unusual fiber element that is simply a variably spun birefringent fiber with a spin rate that varies from fast to zero or vice versa is revealed. The novel fiber element can be readily made by the existing fabrication technique, with fairly loose tolerances of the structural parameters. Analytic theory predicts that such a nonuniform fiber element can function as a bulk-optic quarter-wave plate, but with the advantage of being inherently wide band. Experimental evidence confirms the theoretical prediction. With such a fiber-optic analog of a quarter-wave plate as a building block, wide-band half-wave plates and full wave plates can likewise be made in the form of variably spun birefringent fibers.