Low-loss c-axis oriented ZnMgO nonlinear planar optical waveguides on silicon.

A material platform of highly c-axis oriented ZnMgO thin films is developed for nonlinear planar waveguides and electro-optic modulators on Si. Mg content in the film greatly influences the quality of film growth. The second harmonic generation measurement and Maker-fringe analysis reveal that the second-order nonlinear susceptibility tensor element χ of the annealed ZnMgO is approximately 4.2 times larger than that of ZnO. The propagation loss of 633 nm wavelength light in the annealed air/ZnMgO/SiO slab waveguide is 0.68 ± 0.09 dB/cm and 0.48 ± 0.03 dB/cm for the TE0 and TM0 modes, respectively. These results suggest the great potential of the c-axis oriented ZnMgO nonlinear planar waveguides for applications in on-chip optical interconnects.