Integration of non-volatile ferroelectric actuators in silicon photonics circuits

In this work, we investigate a novel approach to realize non-volatile phase-actuators integrated in silicon photonic waveguides. We aim to exploit the ferroelectric response of polycrystalline BaTiO3 (poly-BTO) grown by pulsed laser deposition (PLD), 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 refractive index variation is partially 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 degrees reorientation of the ferroelectric domains. We also integrated thin poly-BTO films in Si waveguides with a low additional propagation loss (<1 dB/mm), enabling the realization of photonic integrated circuits (PICs) with the proposed poly-BTO Si-photonics platform.