Two kinds of full-filled photonic crystal fibers (PCFs) with different air hole size were investigated by experiments. All
the air holes were filled with liquid crystal (LC). The full-filled part was heated to different temperatures to research the
transmission character. In different temperature conditions, below or over 65°C, the two kinds full-filled LC-PCFs had
their own performance. Mode coupling analysis and LC phase theory were used to explain their different performance.
By researching their output light spots and transmission spectra, we demonstrated that LC-PCFs could be applied in
optical switching, filter, attenuator or other optical devices.