Tunable wavelength filter using nano-sized droplets of liquid crystal

An electrically tunable optical filter has been developed that uses a polymer containing fine droplets of nematic liquid crystal as the active cavity in a Fahry-Perot interferometer (FPI), This FPI filter, whose finesse was 62, had a free spectral range of 37 nm in the 1.55-mu m range with a full-width at half maximum of 0.6 nm and a transmission loss of 2.4 dB, The polarization dependent loss was smaller than 0.17 dB, The transmitted peak wavelength decreased with an electric field. This resulted in a tuning range of 10 nm at 300 V. The switching time was about 370 mu s.