Time efficiency of the electric tuning of index-guiding photonic liquid crystal fiber

Photonic crystal fibers (PCFs) are special class of microstructured fibers composed of the air-holes periodically distributed in the silica cladding. Transmission properties of PCFs can be tailored in a wide range by changing the geometry of their cladding. Dynamic tuning can be obtained after infiltration of the fiber microholes with substances those optical properties could be easily modified by external fields. Liquid crystals (LCs) belong to the most interesting materials for such applications due to the high sensitivities to external physical fields. Photonic liquid crystal fibers (PLCFs) combine unique properties of both photonic crystal fibers and liquid crystals.
Index guiding in PLCFs was observed for the first time in 2006, when the thermal tuning of a guiding mechanism was obtained by using a special LC mixture with the ordinary refractive index lower than the refractive index of silica glass. Later on, low-loss index-guiding propagation was obtained in a PLCF based on a PCF made of high-index glass. The most important advantage of index-guiding propagation in the case of a PLCF is that light scattering is significantly reduced since the mode field is well localized in the fiber’s core, and thus broadband and low-loss propagation is possible. To allow index-guiding, our host fibers were specially tailored from various multicomponent glasses, which refractive index was enhanced to values as high as 1.95.
The impact of an electric field on light propagation in index-guiding PLCFs has been carefully studied and the effective tuning of phase birefringence, attenuation and polarization dependent losses has been observed experimentally.