Results obtained are reported and discussed for Deformed Helix Ferroelectric Liquid Crystal (DHFLC) Fabry Perot etalons which have improved cavity finesse using highly reflective dielectric mirrors. We show that, by the use of the cavities, the response times can be reduced to the order of 10 mu s with <10V applied voltages when the devices are used as optical switches. This is however only true for responses where the transmissions are switched from high to low, i.e. switching out of resonance. Moreover, a shorter pitch DHFLC, Roche FLC 9848, with higher tilt angle has also been used which has faster intrinsic response times and also improves the wavelength tuning range.