Non-volatile ferroelectric actuators integrated in silicon photonic circuits

In this work, we investigate a novel approach to realize non-volatile phase- actuators integrated in silicon waveguides. We aim to exploit the ferroelectric response of polycrystalline BaTiO3 (poly-BTO), whose domain can be re-oriented by applying an external electric field so as to induce a large change of the refractive index. Owing to the polarization remanence of ferroelectric materials, such index variation is maintained when the electric field is turned off. Experimental results on poly-BTO demonstrate the possibility to achieve a non-volatile change of the poly-BTO refractive index in the order of 10-2, which is consistent with a 90° reorientation of the ferroelectric domains. We also integrated thin poly-BTO films on Si waveguides with a low additional propagation loss (<1 dB/mm), enabling the realization of PICs with the proposed poly-BTO Si-photonics platform.