Hybrid amorphous silicon (a-Si:H)–LiNbO3 electro-optic modulator

Here we report the demonstration of a GHz-speed Lithium Niobate (LiNbO3) modulator that uses an amorphous Silicon waveguide to strongly confine light. The compact (<1 mm) modulator is realized by low-temperature deposition of hydrogenated amorphous Silicon (a-Si:H) onto a x-cut LiNbO3 substrate. The a-Si:H provides tight waveguide mode confinement while allowing strong evanescent coupling to the underlying LiNbO3 substrate which, in turn, enables efficient electro-optic modulation. This approach overcomes the traditional drawbacks of low-index contrast LiNbO3 waveguides and consequently is able to realize a strong Pockels effect in a densely integrated Silicon photonics platform. It is expected that this new Si–LiNbO3 platform will enable a multitude of devices and circuits for RF Photonics, nonlinear optics and quantum optics.