Polarization-independent optical fiber modulator by use of polymer-dispersed liquid crystals

Ultrasmall light modulators have been made by sandwiching a polymer-dispersed liquid crystal (PDLC) between two ferrules with optical fibers. The device can modulate light independent of the state of polarization, because the PDLC becomes transparent or opaque when either sufficient or no voltage is applied to the film. The PDLC was prepared by mixing and annealing a prepolymer and nematic liquid crystal with large anisotropy. An optical fiber modulator with a 30-mu m thick PDLC film had an extinction ratio of 8:1-33:1, an insertion loss of 1.3 dB, and rise and decay times of 4 ms at a wavelength of 1.3 mu m. (C) 1998 Optical Society of America.