Li, J.3; Gauza, S.3; Wu, S.-T.3; Alkeskjold, Thomas Tanggaard2; Lægsgaard, Jesper2; Bjarklev, Anders Overgaard4
1 Fibers & Nonlinear Optics, Department of Photonics Engineering, Technical University of Denmark2 Department of Photonics Engineering, Technical University of Denmark3 unknown4 Rector’s office, Administration, Technical University of Denmark
We have analyzed the physical origins of the temperature gradient of the ordinary refractive index (odn/dT) of liquid crystals. To achieve a large odn/dT , high birefringence (Delta n) and low clearing temperature play crucial roles. Based on these guidelines, we formulated two exemplary liquid crystal mixtures, designated as UCF-1 and UCF-2. The dn(o)/dT of UCF-1 is similar to 4x higher than that of 5CB at room temperature. By infiltrating UCF-1 into the air holes of a three-rod core photonic crystal fiber, we demonstrate a thermally tunable photonic bandgap fiber with tuning sensitivity of 27 nm/degrees C at room temperature. The insertion loss is less than 0.5 dB.
Molecular Crystals and Liquid Crystals, 2006, Vol 453, p. 355-370
high dn(o)/dT; liquid crystals; microstructure devices; photonic crystal fiber