Spectral Tuning of the Long-Period Fiber Gratings by Using Low Birefringence Liquid Crystals

The work presented in this paper is focused on investigation of the spectral properties of the long-period fiber gratings combined with the liquid crystals, named liquid crystal long-period fiber gratings. The experiments carried out showed that the proposed designs of the liquid crystal long-period fiber gratings can offer very interesting spectral properties and can introduce a new level of sensitivity. In particular, a high-efficiency thermal tuning of the long-period fiber gratings coated with low-birefringence liquid crystal layers could be achieved and gave rise to a fast and wide switching ability of the attenuation bands within their transmission spectrum.