We propose a new structure of the PLZT thin film optical TIR (Total Internal Reflection) switches with strip loaded type waveguides. Using these switches, we have achieved 2 GHz intensity modulation of LD light (0.83 µm) and 1 km optical fiber transmission. Both lumped constant electrode and traveling wave electrode were examined up to 26.5 GHz. From the calculation of velocity mismatch between the modulating wave and the light wave, it is estimated that the modulation bandwidth of these switches will be more than 100 GHz.