Micro-engineered integrated electro-optic modulators in LiNbO3

Recent developments on micro‐structuring of ferroelectric crystals, such as LiNbO3, have opened up new possibilities for several devices in nonlinear and electro optics. In this paper, after describing the basics of LiNbO3 based integrated electro‐optic modulators, we will show how techniques such as etching, domain inversion and thin film processing can be used to realize new geometries which can take the performance to unprecedented levels. In particular we will report recent results on the use of domain inversion on a micron scale to tailor and improve the electro‐optic response of LiNbO3 waveguide modulators, showing that these applications for domain inversion techniques might be even more important and commercially valuable than those in nonlinear optics (e.g. quasi‐phase‐matched optical parametric devices). With respect to standard single‐domain structures, larger bandwidths and lower driving voltages can be obtained, thus achieving figure of merits for the electro‐optic response that are up to 50%...