SINGLE HELIX CHIRAL FIBER GRATING

摘要

A chiral fiber grating, for reflecting, scattering or polarizing an optical signal, or for forming a fiber Saser feedback structure, comprises a chiral fiber having a singie heiix structure aiorsg its central longitudinal axis having a pitch equal to its period. The single heiix structure is achieved by ensuring that a chiral fiber is asymmetrical about its centra! longitudinal axis prior to twisting the fiber to produce the single helix chiral fiber grating, in an alternate embodiment of the present invention, a hybrid single heiix structure with certain double-helix properties may be produced by utilizing a fiber preform that has a 180 degree symmetrical core, that is asymmetrically offset from the preterm's longitudinal axis. Such a hybrid chiral fiber grating has a spectral response profile that includes, over certain waveSengths of Sight, spectral regions of polarization insensitivity, as well as spectra! regions of polarization sensitivity.