A chiral fiber grating for reflecting, scattering or polarizing an optical
signal, or for forming a fiber laser feedback structure is disclosed. The
chiral fiber grating is fabricated by fusing and then twisting/drawing
two tapered optical fibers in accordance with a predetermined fabrication
protocol. In one embodiment of the invention, the chiral fiber grating
includes two single helix structure end-regions, with a double helix
structure therebetween, providing the grating with apodizing properties.
In another embodiment of invention, the pitch profile along a portion of
the grating is configured to produce desired chiral fiber grating
properties. In yet another embodiment of the invention, the chiral fiber
grating, comprising two single helix end regions and a middle double
helix region, may be separated into two or more portions after
fabrication, for example to provide one or more single helix chiral fiber
gratings and one or more double helix chiral fiber gratings. In an
alternate embodiment of the invention, a double helix structure chiral
fiber grating is provided by twisting two parallel optical fibers around
a longitudinal central axis positioned therebetween.