Organic electro-optic modulator using transparent conducting oxides as electrodes

A novel organic electro-optic (EO) modulator using transparent conducting oxides (ZnO and In₂O₃) as electrodes is demonstrated for the first time. The modulator employs the poled guest-host chromophore/polymer material AJL8/APC having r₃₃=35pm/V and is able to achieve a low V_π=2.8 V switching voltage for an 8mm-long device at a wavelength of 1.31μm. This corresponds to a V_π=1.1 V switching voltage for a 1cm-long device in a push-pull configuration. The push-pull V _πL figure of merit normalized for the EO coefficient is thus 1.1V-cm/(35 pm/V), which is 3-4x lower than that can be achieved with a convetional modulator structure. The bottom electrode is ZnO grown by Metal-Organic Vapor Deposition (MOCVD) and top electrode In₂O ₃ deposited using ion-beam assisted deposition. The top electrode is directly deposited on the guest-host organic material. The design and fabrication considerations for the modulator are also discussed.