Ferroelectric liquid crystal driving method for optical switching devices in communication networks

The requirements that must be met by ferroelectric liquid crystal (FLC) cells in long-wavelength optical switches in communication networks are clarified with respect to the differences from display technology. A new driving method in which low sustain voltage is stored in active-matrix FLC cell was presented and demonstrated experimentally. The memory ratio, extinction ratio and response time of cells 4-5 μm thick were investigated to use at wavelength of 1.3-1.6 μm. Thick cells driven with this new method show response time less than 100 μsec, extinction ratios greater than 30 dB and memory ratios about 98%. The initial aging characteristics of cells driven with the new method indicate that this will result in longer cell lifetime.