Chiral fiber grating device and method of fabrication thereof

Abstract

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.