Continuously tunable all-in-fiber devices based on thermal and electrical control of negative dielectric anisotropy liquid crystal photonic bandgap fibers.

We infiltrate photonic crystal fibers with a negative dielectric anisotropy liquid crystal. A 396 nm bandgap shift is obtained in the temperature range of 22-80 degrees C, and a 67 nm shift of long-wavelength bandgap edge is achieved by applying a voltage of 200 Vrms. The polarization sensitivity and corresponding activation loss are measured using polarized light and a full broadband polarization control setup. The electrically induced phase shift on the Poincaré sphere and corresponding birefringence change are also measured. According to the results, tunable wave plates working in the wavelength range of 1520-1580 nm and a potential for realizing a polarimeter working at the 1310 nm region are experimentally demonstrated.