High efficiency electro-optic polymer/TiO2 waveguide modulators

In this work, we have demonstrated a phase modulator and a ring resonator modulator by using a thin TiO2 and electrooptic (EO) polymer derived hybrid waveguide structure. This TiO2 layer enables the modulators to be constituted without a top cladding, and also can enhance in-device EO coefficient from 70 to 120 pm/V. We utilized the high refractive index TiO2 to confine a large fraction of light in the relatively low refractive index EO polymer layer. As a result, the phase modulator has a VπL of 3.3 V·cm, corresponding to 1.65 V·cm in a push-pull Mach-Zehnder interferometer structure. For the ring modulator, the resonance was observed to shift by 0.02 nm/V, and a modulation depth of 3dB was observed at the frequency response function at 20 kHz using 2 Vp-p clock signal.