Thin LiNbO3 on insulator electro-optic modulator

This Letter presents a method for the fabrication and integration of a thin LiNbO3 substrate with a Si handle wafer. An inverted ridge structure guides a single optical mode in an electro-optic modulator fabricated on a mechanically thinned substrate. To define an optical waveguide, a ridge structure is first patterned on a 500 μm thick X-cut LiNbO3 wafer; then a low dielectric constant adhesive layer is used to bond the etched LiNbO3 to Si. The LiNbO3 is mechanically thinned to 4 μm, and planar electrodes are patterned. Experimental results demonstrating modulation with a V(π)L of 7.1 V-cm were shown, optical loss was low enough, and film quality high enough, to enable an interaction length of 0.8 cm.