Compounds of formula or or salts, N-oxides. Each memory element has a pair of the thin film transistors. This integrated optic Polarization Beam Splitter is broadband, has high extinction ratio, and has characteristics that are tunable. A sheet-shaped wiring board supplies a drive signal to the drive electrode and applies a bias potential which is higher than a ground potential to the common electrode. The first electrode is placed on the base and the second electrode placed in the membrane, the first and second electrodes being connected with a voltage source.