Ferroelectric Liquid Crystal Mixture Integrated Into Optical Waveguides

We report an on-chip integrated ferroelectric liquid crystal (FLC) waveguide structure suitable for telecommunication applications. Single gaps with different widths of 5, 10, and 20 μ m inside individual silica waveguides were filled with an FLC mixture. The waveguide devices operate as a binary switch or an attenuator in a temperature range from 30 ^° C to 60 ^° C. The FLC mixture exhibited a good alignment quality in these gaps without alignment layers. A good extinction ratio of up to 33.9 dB and a low insertion loss of <; 4.3 dB at λ = 1550 nm were observed. Switching times of <; 100 μs were obtained for the low electric fields applied in this experiment.