Photonic crystal fibers (PCF) have been selectively filled with a cholesteric liquid crystal (ChLC) with special interest in
the blue phase (BP) of the liquid crystal. It has been observed thermal tuning of the guided light in the visible region. A
dramatically enhance appears when the phase of the liquid crystal changes from cholesteric to blue phase I (BPI). When
a thermal range of the blue phase I is achieved, no changes are observed while increasing temperature from BPI through
BPII and to the isotropic phase.