||The unique optical properties of photonic crystal fibers (PCFs) are mainly determined by the size and distribution of the air holes in the fiber cladding region. However, it is difficult to modulate the optical properties of fabricated PCFs due to the fixed geometries. By filling index-tunable materials into the air holes of PCFs, we can realize tunable PCFs.|
In this thesis, we simulate the optical properties of PCFs filled with index-tunable materials. The relationships between the effective index of the liquid crystal (LCs) and the external environment (illumination, electric field, temperature) are determined. We first use a 3-D beam propagation method (BPM) to simulate the transmission spectra of the photonic liquid crystal fibers (PLCFs). The results show that as the applied voltage is from 0V to 90V, the effective index of LCs raises only 0.025. As the applied voltage is from 90V to 200V, the effective index of LCs increases by 0.063. Next, we demonstrate tunable of the effective index of the LCs by changing the temperature. The effective index of LCs increases rapidly as the operation temperature is from 40oC to 59oC.
We also simulate the transmission spectra of the light-controllable PLCFs with variant 4MAB concentrations. The results show that as the blue-laser irradiation time is 5 seconds, the effective indices of LCs doped with variant concentrations of 4MAB are the same. However, as the blue-laser irradiation time is from 5 to 25 seconds, the effective index of LCs doped with 20wt% 4MAB only increases 0.002. On the contrary, the effective indices of LCs doped with 25wt% and 30wt% 4MAB increase by 0.0062 and 0.008, respectively.